.section Architecture
.topic api.overview
.title DVX GUI API Reference
.toc 0 DVX GUI API Reference
.default
.index DVX API
.index API Reference

.h1 DVX GUI API Reference

DOS Visual eXecutive -- Complete public API documentation generated from source headers.

The DVX GUI is built as a five-layer architecture. Each layer is defined in its own header file. This reference covers every public function, type, and constant.

.h2 Layers

.list
.item dvxTypes.h -- Shared type definitions
.item dvxCursor.h -- Cursor definitions
.item dvxVideo.h -- Layer 1: VESA VBE Video Backend
.item dvxDraw.h -- Layer 2: Drawing Primitives
.item dvxComp.h -- Layer 3: Dirty Rectangle Compositor
.item dvxWm.h -- Layer 4: Window Manager
.item dvxApp.h -- Layer 5: Application API
.item dvxWidget.h -- Widget System
.endlist

.link api.types dvxTypes.h -- Shared Type Definitions
.link api.cursor dvxCursor.h -- Cursor Definitions
.link api.video dvxVideo.h -- Layer 1: VESA VBE Video Backend
.link api.draw dvxDraw.h -- Layer 2: Drawing Primitives
.link api.comp dvxComp.h -- Layer 3: Dirty Rectangle Compositor
.link api.wm dvxWm.h -- Layer 4: Window Manager
.link api.app dvxApp.h -- Layer 5: Application API
.link api.widget dvxWidget.h -- Widget System

.topic api.types
.title dvxTypes.h -- Shared Type Definitions
.toc 1 dvxTypes.h -- Shared Type Definitions
.index dvxTypes.h
.index PixelFormatT
.index DisplayT
.index RectT
.index BlitOpsT
.index BevelStyleT
.index BitmapFontT
.index ColorSchemeT
.index ColorIdE
.index DirtyListT
.index WindowT
.index WindowStackT
.index MenuT
.index MenuItemT
.index MenuBarT
.index ScrollbarT
.index AccelTableT
.index AccelEntryT
.index VideoModeInfoT
.index CursorT

.h1 dvxTypes.h -- Shared Type Definitions

Central type definitions shared across all five layers of the DVX GUI stack. Every header includes this file. Contains no function definitions -- only structs, enums, typedefs, and compile-time constants.

.h2 Core Structures

.h3 PixelFormatT

Describes the pixel encoding for the active VESA video mode. Populated once at startup from the VBE mode info block, then treated as read-only.

.table
  Field                                        Description
  -----                                        -----------
  int32_t bitsPerPixel                         8, 15, 16, or 32
  int32_t bytesPerPixel                        1, 2, 2, or 4
  uint32_t redMask, greenMask, blueMask        Bitmasks for each color channel
  int32_t redShift, greenShift, blueShift      Bit position of each color field
  int32_t redBits, greenBits, blueBits         Number of bits per channel
.endtable

.h3 DisplayT

Single display context passed by pointer through every layer. All drawing targets the backBuf; only dirty rects are flushed to lfb.

.table
  Field                                  Description
  -----                                  -----------
  int32_t width, height                  Screen dimensions in pixels
  int32_t pitch                          Bytes per scanline
  PixelFormatT format                    Active pixel format
  uint8_t *lfb                           Mapped linear framebuffer (VESA LFB)
  uint8_t *backBuf                       System RAM backbuffer
  uint8_t *palette                       768 bytes for 8-bit mode, NULL otherwise
  int32_t clipX, clipY, clipW, clipH     Current clip rectangle
.endtable

.h3 RectT

Rectangle in origin + extent form. Used throughout the compositor, window manager, and widget layout engine.

.table
  Field              Description
  -----              -----------
  int32_t x, y       Top-left corner
  int32_t w, h       Width and height
.endtable

.h3 BlitOpsT

Vtable for hot-path span operations. Resolved at init time based on pixel depth. On DOS, these dispatch to hand-written asm (rep stosl / rep movsd).

.table
  Field                    Description
  -----                    -----------
  SpanFillFnT spanFill     Fill a horizontal span with a solid color
  SpanCopyFnT spanCopy     Copy a horizontal span between buffers
  int32_t bytesPerPixel    Bytes per pixel for the active mode
  int32_t pitch            Bytes per scanline
.endtable

.h3 BevelStyleT

Bevel drawing parameters. Swapping highlight/shadow flips raised vs. sunken appearance.

.table
  Field                  Description
  -----                  -----------
  uint32_t highlight     Lighter color (top/left edges)
  uint32_t shadow        Darker color (bottom/right edges)
  uint32_t face          Interior fill color (0 = no fill)
  int32_t width          Border thickness in pixels (typically 2)
.endtable

.h3 BitmapFontT

Fixed-width 8-pixel-wide bitmap font descriptor. One size provided: 8x16 (standard VGA ROM font, CP437 encoding).

.table
  Field                          Description
  -----                          -----------
  int32_t charWidth              Fixed width per glyph (always 8)
  int32_t charHeight             Glyph height (14 or 16)
  int32_t firstChar              ASCII code of first glyph (typically 0)
  int32_t numChars               Number of glyphs (typically 256)
  const uint8_t *glyphData       Packed 1bpp data, charHeight bytes per glyph
.endtable

.h3 ColorSchemeT

All UI colors pre-packed into display pixel format at init time. Theme support is achieved by swapping this struct.

.table
  Field                                              Description
  -----                                              -----------
  uint32_t desktop                                   Desktop background color
  uint32_t windowFace                                Window body / chrome face
  uint32_t windowHighlight                           Bevel highlight (top/left edge)
  uint32_t windowShadow                              Bevel shadow (bottom/right edge)
  uint32_t activeTitleBg, activeTitleFg              Focused window title bar
  uint32_t inactiveTitleBg, inactiveTitleFg          Unfocused window title bar
  uint32_t contentBg, contentFg                      Window content area default colors
  uint32_t menuBg, menuFg                            Menu bar and popup background/text
  uint32_t menuHighlightBg, menuHighlightFg          Menu item highlight
  uint32_t buttonFace                                Button face color
  uint32_t scrollbarBg, scrollbarFg, scrollbarTrough Scrollbar element colors
  uint32_t cursorFg, cursorBg                        Mouse cursor colors
.endtable

.h3 ColorIdE

Enum for addressing individual colors in ColorSchemeT. Order matches struct field order.

Values: ColorDesktopE, ColorWindowFaceE, ColorWindowHighlightE, ColorWindowShadowE, ColorActiveTitleBgE, ColorActiveTitleFgE, ColorInactiveTitleBgE, ColorInactiveTitleFgE, ColorContentBgE, ColorContentFgE, ColorMenuBgE, ColorMenuFgE, ColorMenuHighlightBgE, ColorMenuHighlightFgE, ColorButtonFaceE, ColorScrollbarBgE, ColorScrollbarFgE, ColorScrollbarTroughE, ColorCursorFgE, ColorCursorBgE, ColorCountE.

.h3 DirtyListT

Fixed-capacity list of dirty rectangles. Dynamic array, grows on demand.

.table
  Field              Description
  -----              -----------
  RectT *rects       Dynamic array of dirty rectangles
  int32_t count      Current number of dirty rects
  int32_t cap        Allocated capacity
.endtable

.h3 WindowT

Central window object. Each window owns a persistent content backbuffer and receives events through callback function pointers.

.table
  Field                                                          Description
  -----                                                          -----------
  int32_t id                                                     Unique window identifier
  int32_t appId                                                  Shell app ID (0 = shell itself)
  int32_t x, y, w, h                                            Outer frame position and dimensions
  int32_t contentX, contentY, contentW, contentH                 Content area inset from frame
  char title[MAX_TITLE_LEN]                                      Window title text (max 128 chars)
  bool visible, focused, minimized, maximized, resizable, modal  Window state flags
  bool iconNeedsRefresh                                          true when contentBuf changed (for minimized icon refresh)
  bool needsPaint                                                true until first onPaint call
  int32_t maxW, maxH                                             Maximum dimensions
  int32_t preMaxX, preMaxY, preMaxW, preMaxH                    Saved geometry before maximize
  uint8_t *contentBuf                                            Per-window content backbuffer
  int32_t contentPitch                                           Content buffer bytes per row
  uint8_t *iconData                                              Icon pixel data, NULL if none
  int32_t iconW, iconH, iconPitch                                Icon image dimensions and pitch
  MenuBarT *menuBar                                              Menu bar (NULL if no menus)
  ScrollbarT *vScroll, *hScroll                                  Scrollbars (NULL if not present)
  struct WidgetT *widgetRoot                                     Widget tree root (NULL if none)
  MenuT *contextMenu                                             Right-click context menu
  AccelTableT *accelTable                                        Keyboard accelerator table
  void *userData                                                 Application-defined data pointer
.endtable

Callbacks:

.table
  Callback                                                     Description
  --------                                                     -----------
  onPaint(WindowT *win, RectT *dirtyArea)                      Content repaint requested
  onKey(WindowT *win, int32_t key, int32_t mod)                Key press
  onKeyUp(WindowT *win, int32_t scancode, int32_t mod)         Key release
  onMouse(WindowT *win, int32_t x, int32_t y, int32_t btn)    Mouse event (content-relative)
  onResize(WindowT *win, int32_t newW, int32_t newH)           Window resized
  onClose(WindowT *win)                                        Close requested
  onMenu(WindowT *win, int32_t menuId)                         Menu item or accelerator activated
  onScroll(WindowT *win, ScrollbarOrientE orient, int32_t val) Scrollbar value changed
  onCursorQuery(WindowT *win, int32_t x, int32_t y)            Return CURSOR_* for hit position
  onFocus(WindowT *win)                                        Window gained focus
  onBlur(WindowT *win)                                         Window lost focus
.endtable

.h3 WindowStackT

Z-ordered window stack (front-to-back: index count-1 is topmost). Owns system-wide drag/resize/scroll interaction state.

.table
  Field                                        Description
  -----                                        -----------
  WindowT **windows                            Dynamic array of window pointers
  int32_t count, cap                           Current count and allocated capacity
  int32_t focusedIdx                           Stack index of focused window
  int32_t dragWindow, dragOffX, dragOffY       Active drag state
  int32_t resizeWindow, resizeEdge             Active resize state
  int32_t scrollWindow, scrollOrient, scrollDragOff  Active scroll drag state
.endtable

.h3 MenuT / MenuItemT / MenuBarT

Menu system types. Fixed-size label buffers (MAX_MENU_LABEL = 32). Cascading submenus supported via MenuItemT.subMenu pointer.

.table
  Field                        Description
  -----                        -----------
  MenuItemT.label              Item text (supports & accelerator markers)
  MenuItemT.id                 Application-defined command ID
  MenuItemT.type               MenuItemNormalE, MenuItemCheckE, or MenuItemRadioE
  MenuItemT.separator          true = horizontal divider line
  MenuItemT.enabled, checked   Item state
  MenuItemT.subMenu            Child menu for cascading (NULL if leaf)
  MenuBarT.activeIdx           Open popup index (-1 = none)
.endtable

.h3 ScrollbarT

Window-level scrollbar state. Managed by the WM layer, drawn after content.

.table
  Field                        Description
  -----                        -----------
  ScrollbarOrientE orient      ScrollbarVerticalE or ScrollbarHorizontalE
  int32_t min, max             Scroll range
  int32_t value                Current position
  int32_t pageSize             Visible portion (for proportional thumb sizing)
  int32_t x, y, length         Computed screen position and track length
.endtable

.h3 AccelTableT / AccelEntryT

Per-window keyboard accelerator table. Entries are matched against keystrokes in the event loop and fire onMenu(cmdId) on match.

.table
  Field                      Description
  -----                      -----------
  AccelEntryT.key            ASCII character or KEY_Fxx constant
  AccelEntryT.modifiers      Bitmask of ACCEL_CTRL, ACCEL_SHIFT, ACCEL_ALT
  AccelEntryT.cmdId          Command ID passed to onMenu
.endtable

.h3 VideoModeInfoT

Describes an available video mode (enumerated at init).

.table
  Field            Description
  -----            -----------
  int32_t w, h     Resolution
  int32_t bpp      Bits per pixel
.endtable

.h3 CursorT

Software-rendered 16x16 cursor using AND/XOR mask encoding.

.table
  Field                          Description
  -----                          -----------
  int32_t width, height          Cursor dimensions (always 16x16)
  int32_t hotX, hotY             Hot spot coordinates
  const uint16_t *andMask        AND mask (0 = draw pixel, 1 = transparent)
  const uint16_t *xorData        XOR data (0 = black, 1 = white where AND = 0)
.endtable

.h2 Bevel Convenience Macros

.table
  Macro                      Description
  -----                      -----------
  BEVEL_RAISED(cs, bw)       Raised bevel style from ColorSchemeT ptr and border width
  BEVEL_SUNKEN(cs, face, bw) Sunken bevel style with explicit face color
  BEVEL_TROUGH(cs)           1px sunken trough (for scrollbar tracks)
  BEVEL_SB_BUTTON(cs)        1px raised scrollbar button
.endtable

.h2 Chrome Constants

.table
  Define                  Value   Description
  ------                  -----   -----------
  CHROME_BORDER_WIDTH     4       Outer frame border width
  CHROME_TITLE_HEIGHT     20      Title bar height
  CHROME_TITLE_PAD        4       Title text padding
  CHROME_INNER_BORDER     2       Inner chrome border
  CHROME_MENU_HEIGHT      20      Menu bar height
  CHROME_TOTAL_TOP        26      Total inset from top of frame to content
  CHROME_TOTAL_SIDE       6       Total inset from side of frame to content
  CHROME_TOTAL_BOTTOM     6       Total inset from bottom of frame to content
  CHROME_CLOSE_BTN_SIZE   16      Close button gadget size
.endtable

.h2 Hit Test Constants

.table
  Define          Value   Description
  ------          -----   -----------
  HIT_CONTENT     0       Content area
  HIT_TITLE       1       Title bar
  HIT_CLOSE       2       Close gadget
  HIT_RESIZE      3       Resize border
  HIT_MENU        4       Menu bar
  HIT_VSCROLL     5       Vertical scrollbar
  HIT_HSCROLL     6       Horizontal scrollbar
  HIT_MINIMIZE    7       Minimize gadget
  HIT_MAXIMIZE    8       Maximize gadget
  HIT_NONE        -1      No window hit (desktop)
.endtable

.h2 Mouse Button Flags

.table
  Define          Value   Description
  ------          -----   -----------
  MOUSE_LEFT      1       Left mouse button
  MOUSE_RIGHT     2       Right mouse button
  MOUSE_MIDDLE    4       Middle mouse button
.endtable

.h2 Accelerator Modifier Flags

.table
  Define          Value   Description
  ------          -----   -----------
  ACCEL_SHIFT     0x03    Shift key (matches BIOS shift state bits)
  ACCEL_CTRL      0x04    Ctrl key
  ACCEL_ALT       0x08    Alt key
.endtable

.h2 Extended Key Codes

.table
  Define                  Description
  ------                  -----------
  KEY_F1 .. KEY_F12       Function keys (scancode | 0x100)
  KEY_INSERT              Insert key
  KEY_DELETE              Delete key
  KEY_HOME                Home key
  KEY_END                 End key
  KEY_PGUP                Page Up key
  KEY_PGDN                Page Down key
.endtable

.h2 Resize Edge Flags

.table
  Define          Value   Description
  ------          -----   -----------
  RESIZE_NONE     0       No resize edge
  RESIZE_LEFT     1       Left edge
  RESIZE_RIGHT    2       Right edge
  RESIZE_TOP      4       Top edge
  RESIZE_BOTTOM   8       Bottom edge (combinable via OR for corners)
.endtable

.h2 Utility Macros

.table
  Macro           Description
  -----           -----------
  DVX_MIN(a, b)   Return the smaller of two values
  DVX_MAX(a, b)   Return the larger of two values
.endtable

.topic api.cursor
.title dvxCursor.h -- Cursor Definitions
.toc 1 dvxCursor.h -- Cursor Definitions
.index dvxCursor.h
.index Cursor Shapes
.index CURSOR_ARROW
.index CURSOR_BUSY

.h1 dvxCursor.h -- Cursor Definitions

Embedded 16x16 mouse cursor bitmaps compiled as static const data. No external cursor files. Uses the standard AND/XOR mask encoding from the IBM VGA hardware cursor spec.

.h2 Cursor Shape IDs

.table
  Define                      Value   Description
  ------                      -----   -----------
  CURSOR_ARROW                0       Standard arrow (hot spot at tip)
  CURSOR_RESIZE_H             1       Horizontal resize (left/right arrows)
  CURSOR_RESIZE_V             2       Vertical resize (up/down arrows)
  CURSOR_RESIZE_DIAG_NWSE     3       NW-SE diagonal resize
  CURSOR_RESIZE_DIAG_NESW     4       NE-SW diagonal resize
  CURSOR_BUSY                 5       Hourglass (wait)
  CURSOR_CROSSHAIR            6       Crosshair for placement
  CURSOR_COUNT                7       Total number of cursor shapes
.endtable

.h2 Data

.h3 dvxCursors[CURSOR_COUNT]

Static const array of CursorT structs, indexed by CURSOR_xxx constants. Each entry includes the AND mask, XOR data, dimensions, and hot spot coordinates.

.topic api.video
.title dvxVideo.h -- Layer 1: VESA VBE Video Backend
.toc 1 dvxVideo.h -- Layer 1: Video Backend
.index dvxVideo.h
.index videoInit
.index videoShutdown
.index packColor
.index setClipRect
.index resetClipRect
.index VESA
.index LFB

.h1 dvxVideo.h -- Layer 1: VESA VBE Video Backend

The lowest layer. Responsible for VESA VBE mode negotiation, LFB mapping via DPMI, system RAM backbuffer allocation, pixel format discovery, and color packing. LFB-only design: bank switching is deliberately unsupported.

.h2 videoInit

.code
int32_t videoInit(DisplayT *d, int32_t requestedW, int32_t requestedH, int32_t preferredBpp);
.endcode

Probe VBE for a mode matching the requested resolution and depth, enable it, map the LFB into DPMI linear address space, and allocate a system RAM backbuffer. preferredBpp is a hint; the closest available depth is used if an exact match is not found.

.table
  Parameter        Description
  ---------        -----------
  d                Display context to initialize
  requestedW/H     Desired screen resolution
  preferredBpp     Preferred bits per pixel (8, 15, 16, or 32)
.endtable

Returns: 0 on success, negative on failure.

.h2 videoShutdown

.code
void videoShutdown(DisplayT *d);
.endcode

Restore VGA text mode (mode 3), unmap the LFB, and free the backbuffer. Safe to call even if videoInit() failed.

.table
  Parameter   Description
  ---------   -----------
  d           Display context to shut down
.endtable

.h2 packColor

.code
uint32_t packColor(const DisplayT *d, uint8_t r, uint8_t g, uint8_t b);
.endcode

Pack an RGB triplet into the display's native pixel format. For direct-color modes (15/16/32 bpp), returns a packed pixel value using shift/mask fields. For 8-bit mode, returns the nearest palette index via Euclidean distance in RGB space.

.table
  Parameter   Description
  ---------   -----------
  d           Display context (provides pixel format)
  r, g, b     Color components (0-255)
.endtable

Returns: Native pixel value suitable for direct framebuffer write.

.h2 setClipRect

.code
void setClipRect(DisplayT *d, int32_t x, int32_t y, int32_t w, int32_t h);
.endcode

Set the clip rectangle on the display. All subsequent draw operations clip to this rectangle. The caller must save and restore the clip rect around scoped operations.

.table
  Parameter   Description
  ---------   -----------
  d           Display context
  x, y, w, h Clip rectangle in screen coordinates
.endtable

.h2 resetClipRect

.code
void resetClipRect(DisplayT *d);
.endcode

Reset the clip rectangle to the full display dimensions.

.table
  Parameter   Description
  ---------   -----------
  d           Display context
.endtable

.topic api.draw
.title dvxDraw.h -- Layer 2: Drawing Primitives
.toc 1 dvxDraw.h -- Layer 2: Drawing Primitives
.index dvxDraw.h
.index drawInit
.index rectFill
.index rectCopy
.index rectCopyGrayscale
.index drawBevel
.index drawChar
.index drawText
.index drawTextN
.index textWidth
.index accelParse
.index drawTextAccel
.index textWidthAccel
.index drawMaskedBitmap
.index drawTermRow
.index drawFocusRect
.index drawHLine
.index drawVLine

.h1 dvxDraw.h -- Layer 2: Drawing Primitives

All 2D drawing operations: rectangle fills, bitmap blits, text rendering, bevels, lines, and cursor rendering. Every function draws into the display's backbuffer and clips to the current clip rectangle. This layer is stateless beyond the clip rect on DisplayT.

.h2 drawInit

.code
void drawInit(BlitOpsT *ops, const DisplayT *d);
.endcode

Populate a BlitOpsT with the correct span functions for the display's pixel depth. Must be called once after videoInit().

.table
  Parameter   Description
  ---------   -----------
  ops         BlitOpsT to populate
  d           Initialized display context
.endtable

.h2 rectFill

.code
void rectFill(DisplayT *d, const BlitOpsT *ops, int32_t x, int32_t y, int32_t w, int32_t h, uint32_t color);
.endcode

Fill a rectangle with a solid color. Clips to the display clip rect. Workhorse for backgrounds, window fills, and clear operations.

.table
  Parameter   Description
  ---------   -----------
  d           Display context
  ops         Blit operations vtable
  x, y, w, h Rectangle to fill
  color       Packed pixel color
.endtable

.h2 rectCopy

.code
void rectCopy(DisplayT *d, const BlitOpsT *ops, int32_t dstX, int32_t dstY, const uint8_t *srcBuf, int32_t srcPitch, int32_t srcX, int32_t srcY, int32_t w, int32_t h);
.endcode

Copy a rectangle from an arbitrary source buffer into the backbuffer. Used to blit per-window content buffers during compositing.

.table
  Parameter     Description
  ---------     -----------
  d             Display context
  ops           Blit operations vtable
  dstX, dstY    Destination position in backbuffer
  srcBuf        Source pixel buffer
  srcPitch      Source buffer bytes per row
  srcX, srcY    Origin within source buffer
  w, h          Rectangle dimensions to copy
.endtable

.h2 rectCopyGrayscale

.code
void rectCopyGrayscale(DisplayT *d, const BlitOpsT *ops, int32_t dstX, int32_t dstY, const uint8_t *srcBuf, int32_t srcPitch, int32_t srcX, int32_t srcY, int32_t w, int32_t h);
.endcode

Copy a rectangle with grayscale conversion. Each pixel's RGB is converted to luminance (0.299R + 0.587G + 0.114B) for a disabled/grayed appearance.

.table
  Parameter       Description
  ---------       -----------
  d               Display context
  ops             Blit operations vtable
  dstX, dstY      Destination position
  srcBuf, srcPitch Source buffer and pitch
  srcX, srcY      Source origin
  w, h            Rectangle dimensions
.endtable

.h2 drawBevel

.code
void drawBevel(DisplayT *d, const BlitOpsT *ops, int32_t x, int32_t y, int32_t w, int32_t h, const BevelStyleT *style);
.endcode

Draw a beveled frame. Top/left edges in highlight color, bottom/right in shadow. Interior filled with face color if non-zero.

.table
  Parameter   Description
  ---------   -----------
  d           Display context
  ops         Blit operations vtable
  x, y, w, h Outer bevel rectangle
  style       Bevel colors and width
.endtable

.h2 drawChar

.code
int32_t drawChar(DisplayT *d, const BlitOpsT *ops, const BitmapFontT *font, int32_t x, int32_t y, char ch, uint32_t fg, uint32_t bg, bool opaque);
.endcode

Draw a single character glyph. When opaque is true, the background fills the entire cell; when false, only foreground pixels are drawn (transparent background).

.table
  Parameter   Description
  ---------   -----------
  d           Display context
  ops         Blit operations vtable
  font        Bitmap font
  x, y        Character position
  ch          Character to draw
  fg, bg      Foreground and background packed colors
  opaque      true = fill background, false = transparent
.endtable

Returns: Advance width (always charWidth).

.h2 drawText

.code
void drawText(DisplayT *d, const BlitOpsT *ops, const BitmapFontT *font, int32_t x, int32_t y, const char *text, uint32_t fg, uint32_t bg, bool opaque);
.endcode

Draw a null-terminated string. Calls drawChar per character.

.table
  Parameter   Description
  ---------   -----------
  d           Display context
  ops         Blit operations vtable
  font        Bitmap font
  x, y        Start position
  text        Null-terminated string
  fg, bg      Foreground and background packed colors
  opaque      true = fill background, false = transparent
.endtable

.h2 drawTextN

.code
void drawTextN(DisplayT *d, const BlitOpsT *ops, const BitmapFontT *font, int32_t x, int32_t y, const char *text, int32_t count, uint32_t fg, uint32_t bg, bool opaque);
.endcode

Optimized batch text rendering for a known character count. Computes clip bounds once, fills background in a single rectFill, then overlays glyph foreground pixels. Significantly faster than per-character drawChar for long runs (terminal rows, list items).

.table
  Parameter   Description
  ---------   -----------
  d           Display context
  ops         Blit operations vtable
  font        Bitmap font
  x, y        Start position
  text        Character buffer (not required to be null-terminated)
  count       Number of characters to render
  fg, bg      Foreground and background packed colors
  opaque      true = fill background, false = transparent
.endtable

.h2 textWidth

.code
int32_t textWidth(const BitmapFontT *font, const char *text);
.endcode

Return the pixel width of a null-terminated string (strlen(text) * charWidth).

.table
  Parameter   Description
  ---------   -----------
  font        Bitmap font
  text        Null-terminated string
.endtable

Returns: Width in pixels.

.h2 accelParse

.code
char accelParse(const char *text);
.endcode

Scan text for an & prefix and return the following character as a lowercase accelerator key. "&File" returns 'f', "E&xit" returns 'x'.

.table
  Parameter   Description
  ---------   -----------
  text        Text with optional & accelerator marker
.endtable

Returns: Lowercase accelerator character, or 0 if none.

.h2 drawTextAccel

.code
void drawTextAccel(DisplayT *d, const BlitOpsT *ops, const BitmapFontT *font, int32_t x, int32_t y, const char *text, uint32_t fg, uint32_t bg, bool opaque);
.endcode

Draw text with & accelerator markers. The character after & is drawn underlined to indicate the keyboard shortcut. && produces a literal &. Used for menu items and button labels.

.table
  Parameter   Description
  ---------   -----------
  d           Display context
  ops         Blit operations vtable
  font        Bitmap font
  x, y        Start position
  text        Text with & markers
  fg, bg      Foreground and background packed colors
  opaque      true = fill background, false = transparent
.endtable

.h2 textWidthAccel

.code
int32_t textWidthAccel(const BitmapFontT *font, const char *text);
.endcode

Measure text width excluding & markers (so "&File" measures as 4 chars).

.table
  Parameter   Description
  ---------   -----------
  font        Bitmap font
  text        Text with optional & markers
.endtable

Returns: Width in pixels.

.h2 drawMaskedBitmap

.code
void drawMaskedBitmap(DisplayT *d, const BlitOpsT *ops, int32_t x, int32_t y, int32_t w, int32_t h, const uint16_t *andMask, const uint16_t *xorData, uint32_t fgColor, uint32_t bgColor);
.endcode

Draw a 1-bit AND/XOR masked bitmap. Used for software-rendered mouse cursors.

.table
  Parameter       Description
  ---------       -----------
  d               Display context
  ops             Blit operations vtable
  x, y            Screen position
  w, h            Bitmap dimensions
  andMask         AND transparency mask (one uint16_t per row)
  xorData         XOR color data
  fgColor, bgColor Cursor foreground and background packed colors
.endtable

.h2 drawTermRow

.code
void drawTermRow(DisplayT *d, const BlitOpsT *ops, const BitmapFontT *font, int32_t x, int32_t y, int32_t cols, const uint8_t *lineData, const uint32_t *palette, bool blinkVisible, int32_t cursorCol);
.endcode

Render an entire row of terminal character cells (ch/attr byte pairs) in a single pass. Colors looked up from a 16-color palette. Attribute bit 7 controls blink.

.table
  Parameter       Description
  ---------       -----------
  d               Display context
  ops             Blit operations vtable
  font            Bitmap font
  x, y            Row start position
  cols            Number of columns
  lineData        Packed ch/attr byte pairs (2 bytes per cell)
  palette         16-entry packed color palette
  blinkVisible    false = hide blinking characters
  cursorCol       Column for inverted text cursor (-1 = none)
.endtable

.h2 drawFocusRect

.code
void drawFocusRect(DisplayT *d, const BlitOpsT *ops, int32_t x, int32_t y, int32_t w, int32_t h, uint32_t color);
.endcode

Draw a 1px dotted rectangle (alternating pixels). Used for keyboard focus indicators, matching the Windows 3.x focus rectangle convention.

.table
  Parameter   Description
  ---------   -----------
  d           Display context
  ops         Blit operations vtable
  x, y, w, h Focus rectangle bounds
  color       Dot color (packed)
.endtable

.h2 drawHLine

.code
void drawHLine(DisplayT *d, const BlitOpsT *ops, int32_t x, int32_t y, int32_t w, uint32_t color);
.endcode

Draw a horizontal line (1px tall).

.table
  Parameter   Description
  ---------   -----------
  d           Display context
  ops         Blit operations vtable
  x, y        Start position
  w           Width in pixels
  color       Packed pixel color
.endtable

.h2 drawVLine

.code
void drawVLine(DisplayT *d, const BlitOpsT *ops, int32_t x, int32_t y, int32_t h, uint32_t color);
.endcode

Draw a vertical line (1px wide).

.table
  Parameter   Description
  ---------   -----------
  d           Display context
  ops         Blit operations vtable
  x, y        Start position
  h           Height in pixels
  color       Packed pixel color
.endtable

.topic api.comp
.title dvxComp.h -- Layer 3: Dirty Rectangle Compositor
.toc 1 dvxComp.h -- Layer 3: Compositor
.index dvxComp.h
.index dirtyListInit
.index dirtyListAdd
.index dirtyListMerge
.index dirtyListClear
.index flushRect
.index rectIntersect
.index rectIsEmpty

.h1 dvxComp.h -- Layer 3: Dirty Rectangle Compositor

Tracks changed screen regions and ensures only dirty regions are redrawn and flushed to video memory. The compositing pipeline: mark dirty, merge overlapping rects, redraw desktop + windows (back-to-front, painter's algorithm), flush to LFB.

.h2 dirtyListInit

.code
void dirtyListInit(DirtyListT *dl);
.endcode

Zero the dirty rect count. Called at the start of each frame.

.table
  Parameter   Description
  ---------   -----------
  dl          Dirty list to initialize
.endtable

.h2 dirtyListAdd

.code
void dirtyListAdd(DirtyListT *dl, int32_t x, int32_t y, int32_t w, int32_t h);
.endcode

Enqueue a dirty rectangle. Grows dynamically; triggers merge at a soft capacity limit.

.table
  Parameter   Description
  ---------   -----------
  dl          Dirty list
  x, y, w, h Dirty rectangle in screen coordinates
.endtable

.h2 dirtyListMerge

.code
void dirtyListMerge(DirtyListT *dl);
.endcode

Consolidate the dirty list by merging overlapping and adjacent rects. Uses iterative pairwise merge: if combining two rects does not increase total area beyond a threshold, they are merged. Reduces compositor passes and LFB flush operations.

.table
  Parameter   Description
  ---------   -----------
  dl          Dirty list to merge
.endtable

.h2 dirtyListClear

.code
void dirtyListClear(DirtyListT *dl);
.endcode

Reset the dirty list to empty (sets count to 0).

.table
  Parameter   Description
  ---------   -----------
  dl          Dirty list to clear
.endtable

.h2 flushRect

.code
void flushRect(DisplayT *d, const RectT *r);
.endcode

Copy a rectangle from the system RAM backbuffer to the LFB (video memory). This is the only place the real framebuffer is written. Uses platform-specific fast copy (rep movsd on DOS) for each scanline.

.table
  Parameter   Description
  ---------   -----------
  d           Display context
  r           Rectangle to flush
.endtable

.h2 rectIntersect

.code
bool rectIntersect(const RectT *a, const RectT *b, RectT *result);
.endcode

Compute the intersection of two rectangles.

.table
  Parameter   Description
  ---------   -----------
  a, b        Input rectangles
  result      Output: intersection rectangle (valid only when return is true)
.endtable

Returns: true if the rectangles overlap, false if disjoint.

.h2 rectIsEmpty

.code
bool rectIsEmpty(const RectT *r);
.endcode

Test whether a rectangle has zero or negative area.

.table
  Parameter   Description
  ---------   -----------
  r           Rectangle to test
.endtable

Returns: true if w <= 0 or h <= 0.

.topic api.wm
.title dvxWm.h -- Layer 4: Window Manager
.toc 1 dvxWm.h -- Layer 4: Window Manager
.index dvxWm.h
.index wmInit
.index wmCreateWindow
.index wmDestroyWindow
.index wmRaiseWindow
.index wmSetFocus
.index wmUpdateContentRect
.index wmReallocContentBuf
.index wmMinWindowSize
.index wmAddMenuBar
.index wmAddMenu
.index wmAddMenuItem
.index wmAddSubMenu
.index wmCreateMenu
.index wmDrawChrome
.index wmHitTest
.index wmDragBegin
.index wmResizeBegin
.index wmMaximize
.index wmMinimize
.index wmRestore

.h1 dvxWm.h -- Layer 4: Window Manager

Manages the window lifecycle, Z-order stack, chrome drawing, hit testing, and interactive operations (drag, resize, scroll). The WM owns window geometry and chrome; content is owned by the application via callbacks or the widget system.

.h2 Initialization

.h3 wmInit

.code
void wmInit(WindowStackT *stack);
.endcode

Zero the window stack. Must be called before any other WM function.

.table
  Parameter   Description
  ---------   -----------
  stack       Window stack to initialize
.endtable

.h2 Window Lifecycle

.h3 wmCreateWindow

.code
WindowT *wmCreateWindow(WindowStackT *stack, DisplayT *d, const char *title, int32_t x, int32_t y, int32_t w, int32_t h, bool resizable);
.endcode

Allocate a new window, initialize its geometry and content buffer, and push it to the top of the Z-order stack. Returns with all callbacks NULL; the caller should set onPaint/onKey/etc. before the next event loop iteration.

.table
  Parameter   Description
  ---------   -----------
  stack       Window stack
  d           Display context
  title       Window title text
  x, y        Initial position
  w, h        Initial outer frame dimensions
  resizable   true = allow user resize
.endtable

Returns: Pointer to new WindowT, or NULL on failure.

.h3 wmDestroyWindow

.code
void wmDestroyWindow(WindowStackT *stack, WindowT *win);
.endcode

Free the window's content buffer and all attached resources (menu bar, scrollbars, widget tree), remove it from the stack, and dirty the vacated region.

.table
  Parameter   Description
  ---------   -----------
  stack       Window stack
  win         Window to destroy
.endtable

.h2 Z-Order and Focus

.h3 wmRaiseWindow

.code
void wmRaiseWindow(WindowStackT *stack, DirtyListT *dl, int32_t idx);
.endcode

Move window at stack index idx to the top of the Z-order. Dirties both old and new top positions so overlapping windows get repainted.

.table
  Parameter   Description
  ---------   -----------
  stack       Window stack
  dl          Dirty list for repaint marking
  idx         Stack index of window to raise
.endtable

.h3 wmSetFocus

.code
void wmSetFocus(WindowStackT *stack, DirtyListT *dl, int32_t idx);
.endcode

Transfer keyboard focus to the window at stack index idx. Unfocuses the previously focused window and dirties both title bars.

.table
  Parameter   Description
  ---------   -----------
  stack       Window stack
  dl          Dirty list
  idx         Stack index of window to focus
.endtable

.h2 Geometry

.h3 wmUpdateContentRect

.code
void wmUpdateContentRect(WindowT *win);
.endcode

Recompute contentX/Y/W/H from the window's outer frame dimensions, accounting for chrome borders, title bar, menu bar, and scrollbars. Must be called after any change to frame size or chrome configuration.

.table
  Parameter   Description
  ---------   -----------
  win         Window to update
.endtable

.h3 wmReallocContentBuf

.code
int32_t wmReallocContentBuf(WindowT *win, const DisplayT *d);
.endcode

Reallocate the per-window content backbuffer to match current contentW/H. Old buffer contents are lost; caller should trigger a full repaint via onPaint afterward.

.table
  Parameter   Description
  ---------   -----------
  win         Window to reallocate
  d           Display context (for bytes-per-pixel)
.endtable

Returns: 0 on success, -1 on allocation failure.

.h3 wmMinWindowSize

.code
void wmMinWindowSize(const WindowT *win, int32_t *minW, int32_t *minH);
.endcode

Get the minimum window size. Accounts for chrome, gadgets, and menu bar.

.table
  Parameter    Description
  ---------    -----------
  win          Window
  minW, minH   Output: minimum width and height
.endtable

.h2 Menu Bar

.h3 wmAddMenuBar

.code
MenuBarT *wmAddMenuBar(WindowT *win);
.endcode

Allocate and attach a menu bar to a window. Adjusts content area to make room (CHROME_MENU_HEIGHT pixels). One menu bar per window.

.table
  Parameter   Description
  ---------   -----------
  win         Window to add menu bar to
.endtable

Returns: Pointer to the new MenuBarT.

.h3 wmDestroyMenuBar

.code
void wmDestroyMenuBar(WindowT *win);
.endcode

Free the menu bar and reclaim the content area.

.table
  Parameter   Description
  ---------   -----------
  win         Window to remove menu bar from
.endtable

.h3 wmAddMenu

.code
MenuT *wmAddMenu(MenuBarT *bar, const char *label);
.endcode

Append a dropdown menu to the menu bar. The label supports & accelerator markers (e.g. "&File").

.table
  Parameter   Description
  ---------   -----------
  bar         Menu bar
  label       Menu label text
.endtable

Returns: Pointer to the new MenuT to populate with items.

.h3 wmAddMenuItem

.code
void wmAddMenuItem(MenuT *menu, const char *label, int32_t id);
.endcode

Append a clickable item to a menu. The id is passed to the window's onMenu callback when selected.

.table
  Parameter   Description
  ---------   -----------
  menu        Menu to append to
  label       Item label (supports & markers)
  id          Application-defined command ID
.endtable

.h3 wmAddMenuCheckItem

.code
void wmAddMenuCheckItem(MenuT *menu, const char *label, int32_t id, bool checked);
.endcode

Add a checkbox-style menu item. Check state toggles on click; rendered with a checkmark glyph.

.table
  Parameter   Description
  ---------   -----------
  menu        Menu to append to
  label       Item label
  id          Command ID
  checked     Initial checked state
.endtable

.h3 wmAddMenuRadioItem

.code
void wmAddMenuRadioItem(MenuT *menu, const char *label, int32_t id, bool checked);
.endcode

Add a radio-style menu item. Radio groups are defined implicitly by consecutive radio items; selecting one unchecks the others in the group.

.table
  Parameter   Description
  ---------   -----------
  menu        Menu to append to
  label       Item label
  id          Command ID
  checked     Initial checked state
.endtable

.h3 wmAddMenuSeparator

.code
void wmAddMenuSeparator(MenuT *menu);
.endcode

Insert a horizontal separator line. Separators are not interactive.

.table
  Parameter   Description
  ---------   -----------
  menu        Menu to append separator to
.endtable

.h3 wmMenuItemIsChecked

.code
bool wmMenuItemIsChecked(MenuBarT *bar, int32_t id);
.endcode

Query the checked state of a menu item by command ID. Searches all menus in the bar.

.table
  Parameter   Description
  ---------   -----------
  bar         Menu bar
  id          Command ID to query
.endtable

Returns: true if checked.

.h3 wmMenuItemSetChecked

.code
void wmMenuItemSetChecked(MenuBarT *bar, int32_t id, bool checked);
.endcode

Set the checked state of a menu item by command ID. For radio items, setting checked=true also unchecks other radio items in the same group.

.table
  Parameter   Description
  ---------   -----------
  bar         Menu bar
  id          Command ID
  checked     New checked state
.endtable

.h3 wmMenuItemSetEnabled

.code
void wmMenuItemSetEnabled(MenuBarT *bar, int32_t id, bool enabled);
.endcode

Enable or disable a menu item by command ID.

.table
  Parameter   Description
  ---------   -----------
  bar         Menu bar
  id          Command ID
  enabled     true = enabled, false = grayed out
.endtable

.h3 wmAddSubMenu

.code
MenuT *wmAddSubMenu(MenuT *parentMenu, const char *label);
.endcode

Create a cascading submenu attached to a parent menu. The child MenuT is heap-allocated and freed when the parent window is destroyed.

.table
  Parameter    Description
  ---------    -----------
  parentMenu   Parent menu to attach submenu to
  label        Submenu label text
.endtable

Returns: Pointer to the child MenuT, or NULL on allocation failure.

.h3 wmCreateMenu

.code
MenuT *wmCreateMenu(void);
.endcode

Allocate a heap-resident MenuT for use as a context menu (right-click). Unlike menu bar menus, context menus are standalone allocations. Free with wmFreeMenu().

Returns: Pointer to the new MenuT.

.h3 wmFreeMenu

.code
void wmFreeMenu(MenuT *menu);
.endcode

Free a standalone menu allocated with wmCreateMenu(). Also frees any heap-allocated submenu children recursively.

.table
  Parameter   Description
  ---------   -----------
  menu        Menu to free
.endtable

.h2 Scrollbars

.h3 wmAddVScrollbar

.code
ScrollbarT *wmAddVScrollbar(WindowT *win, int32_t min, int32_t max, int32_t pageSize);
.endcode

Attach a vertical scrollbar to the right edge of the window's content area. Shrinks contentW by SCROLLBAR_WIDTH pixels.

.table
  Parameter   Description
  ---------   -----------
  win         Window
  min, max    Scroll value range
  pageSize    Visible portion (controls thumb size)
.endtable

Returns: Pointer to the new ScrollbarT.

.h3 wmAddHScrollbar

.code
ScrollbarT *wmAddHScrollbar(WindowT *win, int32_t min, int32_t max, int32_t pageSize);
.endcode

Attach a horizontal scrollbar to the bottom edge. Shrinks contentH by SCROLLBAR_WIDTH pixels.

.table
  Parameter   Description
  ---------   -----------
  win         Window
  min, max    Scroll value range
  pageSize    Visible portion
.endtable

Returns: Pointer to the new ScrollbarT.

.h2 Drawing

.h3 wmDrawChrome

.code
void wmDrawChrome(DisplayT *d, const BlitOpsT *ops, const BitmapFontT *font, const ColorSchemeT *colors, WindowT *win, const RectT *clipTo);
.endcode

Draw the window frame: outer bevel, title bar with text, close/minimize/maximize gadgets, and menu bar if present. Drawing is clipped to the intersection with clipTo.

.table
  Parameter   Description
  ---------   -----------
  d           Display context
  ops         Blit operations vtable
  font        Bitmap font for title text
  colors      Color scheme
  win         Window to draw chrome for
  clipTo      Dirty rectangle to clip drawing to
.endtable

.h3 wmDrawContent

.code
void wmDrawContent(DisplayT *d, const BlitOpsT *ops, WindowT *win, const RectT *clipTo);
.endcode

Blit the window's content backbuffer into the display backbuffer, clipped to the dirty rect. Pure copy operation (no drawing).

.table
  Parameter   Description
  ---------   -----------
  d           Display context
  ops         Blit operations vtable
  win         Window
  clipTo      Dirty rectangle
.endtable

.h3 wmDrawScrollbars

.code
void wmDrawScrollbars(DisplayT *d, const BlitOpsT *ops, const ColorSchemeT *colors, WindowT *win, const RectT *clipTo);
.endcode

Draw scrollbars (track, arrows, proportional thumb) for a window. Drawn after content so scrollbars overlay the content area edge.

.table
  Parameter   Description
  ---------   -----------
  d           Display context
  ops         Blit operations vtable
  colors      Color scheme
  win         Window
  clipTo      Dirty rectangle
.endtable

.h3 wmDrawMinimizedIcons

.code
void wmDrawMinimizedIcons(DisplayT *d, const BlitOpsT *ops, const ColorSchemeT *colors, const WindowStackT *stack, const RectT *clipTo);
.endcode

Draw icons for all minimized windows along the bottom of the screen. Each icon shows a scaled preview of the window's content with a beveled border.

.table
  Parameter   Description
  ---------   -----------
  d           Display context
  ops         Blit operations vtable
  colors      Color scheme
  stack       Window stack
  clipTo      Dirty rectangle
.endtable

.h2 Hit Testing

.h3 wmHitTest

.code
int32_t wmHitTest(const WindowStackT *stack, int32_t mx, int32_t my, int32_t *hitPart);
.endcode

Determine which window and chrome region is under the given screen coordinates. Iterates front-to-back (highest Z first) so the topmost window wins.

.table
  Parameter   Description
  ---------   -----------
  stack       Window stack
  mx, my      Screen coordinates
  hitPart     Output: HIT_CONTENT, HIT_TITLE, HIT_CLOSE, etc.
.endtable

Returns: Stack index of hit window, or -1 for desktop.

.h3 wmResizeEdgeHit

.code
int32_t wmResizeEdgeHit(const WindowT *win, int32_t mx, int32_t my);
.endcode

Determine which edge(s) of a window's border zone are targeted for resize.

.table
  Parameter   Description
  ---------   -----------
  win         Window
  mx, my      Screen coordinates
.endtable

Returns: Bitmask of RESIZE_LEFT / RESIZE_RIGHT / RESIZE_TOP / RESIZE_BOTTOM.

.h3 wmMinimizedIconHit

.code
int32_t wmMinimizedIconHit(const WindowStackT *stack, const DisplayT *d, int32_t mx, int32_t my);
.endcode

Hit-test minimized icons at the bottom of the screen.

.table
  Parameter   Description
  ---------   -----------
  stack       Window stack
  d           Display context
  mx, my      Screen coordinates
.endtable

Returns: Stack index of the minimized window, or -1.

.h2 Drag and Resize

.h3 wmDragBegin

.code
void wmDragBegin(WindowStackT *stack, int32_t idx, int32_t mouseX, int32_t mouseY);
.endcode

Begin a window drag operation. Records the mouse offset from the window origin.

.table
  Parameter     Description
  ---------     -----------
  stack         Window stack
  idx           Stack index of window to drag
  mouseX/Y      Current mouse position
.endtable

.h3 wmDragMove

.code
void wmDragMove(WindowStackT *stack, DirtyListT *dl, int32_t mouseX, int32_t mouseY, int32_t screenW, int32_t screenH);
.endcode

Update window position during an active drag. Dirties both old and new positions.

.table
  Parameter      Description
  ---------      -----------
  stack          Window stack
  dl             Dirty list
  mouseX/Y       Current mouse position
  screenW/H      Screen dimensions (for clamping)
.endtable

.h3 wmDragEnd

.code
void wmDragEnd(WindowStackT *stack);
.endcode

End the current drag operation. Clears dragWindow state.

.table
  Parameter   Description
  ---------   -----------
  stack       Window stack
.endtable

.h3 wmResizeBegin

.code
void wmResizeBegin(WindowStackT *stack, int32_t idx, int32_t edge, int32_t mouseX, int32_t mouseY);
.endcode

Begin a window resize operation. Records which edge(s) are being dragged.

.table
  Parameter   Description
  ---------   -----------
  stack       Window stack
  idx         Stack index
  edge        Bitmask of RESIZE_xxx flags
  mouseX/Y    Current mouse position
.endtable

.h3 wmResizeMove

.code
void wmResizeMove(WindowStackT *stack, DirtyListT *dl, const DisplayT *d, int32_t *mouseX, int32_t *mouseY);
.endcode

Update window dimensions during an active resize. Enforces MIN_WINDOW_W/H and maxW/maxH constraints. Reallocates content buffer and calls onResize if size changed. mouseX/mouseY are in/out: clamped on return for cursor warping.

.table
  Parameter   Description
  ---------   -----------
  stack       Window stack
  dl          Dirty list
  d           Display context
  mouseX/Y    In/out: mouse position (clamped on return)
.endtable

.h3 wmResizeEnd

.code
void wmResizeEnd(WindowStackT *stack);
.endcode

End the current resize operation. Clears resizeWindow state.

.table
  Parameter   Description
  ---------   -----------
  stack       Window stack
.endtable

.h2 Scrollbar Interaction

.h3 wmScrollbarClick

.code
void wmScrollbarClick(WindowStackT *stack, DirtyListT *dl, int32_t idx, int32_t orient, int32_t mx, int32_t my);
.endcode

Handle an initial click on a scrollbar. Determines what was hit (arrows, trough, or thumb) and either adjusts the value immediately or begins a thumb drag.

.table
  Parameter   Description
  ---------   -----------
  stack       Window stack
  dl          Dirty list
  idx         Stack index of window
  orient      SCROLL_VERTICAL or SCROLL_HORIZONTAL
  mx, my      Click screen coordinates
.endtable

.h3 wmScrollbarDrag

.code
void wmScrollbarDrag(WindowStackT *stack, DirtyListT *dl, int32_t mx, int32_t my);
.endcode

Update the scroll value during an active thumb drag. Maps mouse position along the track to a proportional scroll value.

.table
  Parameter   Description
  ---------   -----------
  stack       Window stack
  dl          Dirty list
  mx, my      Current mouse position
.endtable

.h3 wmScrollbarEnd

.code
void wmScrollbarEnd(WindowStackT *stack);
.endcode

End an active scrollbar thumb drag.

.table
  Parameter   Description
  ---------   -----------
  stack       Window stack
.endtable

.h2 Minimize / Maximize / Restore

.h3 wmMaximize

.code
void wmMaximize(WindowStackT *stack, DirtyListT *dl, const DisplayT *d, WindowT *win);
.endcode

Maximize a window. Saves current geometry, then expands to screen or maxW/maxH bounds.

.table
  Parameter   Description
  ---------   -----------
  stack       Window stack
  dl          Dirty list
  d           Display context
  win         Window to maximize
.endtable

.h3 wmMinimize

.code
void wmMinimize(WindowStackT *stack, DirtyListT *dl, WindowT *win);
.endcode

Minimize a window. Hides the window and shows an icon at the bottom of the screen.

.table
  Parameter   Description
  ---------   -----------
  stack       Window stack
  dl          Dirty list
  win         Window to minimize
.endtable

.h3 wmRestore

.code
void wmRestore(WindowStackT *stack, DirtyListT *dl, const DisplayT *d, WindowT *win);
.endcode

Restore a maximized window to its pre-maximize geometry.

.table
  Parameter   Description
  ---------   -----------
  stack       Window stack
  dl          Dirty list
  d           Display context
  win         Maximized window to restore
.endtable

.h3 wmRestoreMinimized

.code
void wmRestoreMinimized(WindowStackT *stack, DirtyListT *dl, const DisplayT *d, WindowT *win);
.endcode

Restore a minimized window (show it again and remove the icon).

.table
  Parameter   Description
  ---------   -----------
  stack       Window stack
  dl          Dirty list
  d           Display context
  win         Minimized window to restore
.endtable

.h2 Minimized Icon Layout

.h3 wmMinimizedIconPos

.code
void wmMinimizedIconPos(const DisplayT *d, int32_t index, int32_t *x, int32_t *y);
.endcode

Compute the screen position of a minimized icon by ordinal index. Icons wrap into rows from bottom to top when the screen fills up.

.table
  Parameter   Description
  ---------   -----------
  d           Display context
  index       Ordinal index of the minimized icon
  x, y        Output: screen position
.endtable

.h3 wmMinimizedIconRect

.code
void wmMinimizedIconRect(const WindowStackT *stack, const DisplayT *d, int32_t *y, int32_t *h);
.endcode

Compute the screen rect covering all minimized icon rows. Used to dirty the icon area when windows are minimized or restored.

.table
  Parameter   Description
  ---------   -----------
  stack       Window stack
  d           Display context
  y, h        Output: vertical extent of icon area
.endtable

.h2 Miscellaneous

.h3 wmSetTitle

.code
void wmSetTitle(WindowT *win, DirtyListT *dl, const char *title);
.endcode

Set the window title and dirty the title bar for repaint.

.table
  Parameter   Description
  ---------   -----------
  win         Window
  dl          Dirty list
  title       New title text
.endtable

.h3 wmSetIcon

.code
int32_t wmSetIcon(WindowT *win, const char *path, const DisplayT *d);
.endcode

Load an icon image for a window from a file. Converts to display pixel format.

.table
  Parameter   Description
  ---------   -----------
  win         Window
  path        Image file path
  d           Display context
.endtable

Returns: 0 on success, -1 on failure.

.topic api.app
.title dvxApp.h -- Layer 5: Application API
.toc 1 dvxApp.h -- Layer 5: Application API
.index dvxApp.h
.index AppContextT
.index dvxInit
.index dvxShutdown
.index dvxRun
.index dvxUpdate
.index dvxQuit
.index dvxCreateWindow
.index dvxCreateWindowCentered
.index dvxDestroyWindow
.index dvxRaiseWindow
.index dvxFitWindow
.index dvxResizeWindow
.index dvxMinimizeWindow
.index dvxMaximizeWindow
.index dvxHideWindow
.index dvxShowWindow
.index dvxInvalidateRect
.index dvxInvalidateWindow
.index dvxSetTitle
.index dvxSetWindowIcon
.index dvxSetBusy
.index dvxGetFont
.index dvxGetColors
.index dvxGetDisplay
.index dvxGetBlitOps
.index dvxGetVideoModes
.index dvxSetColor
.index dvxGetColor
.index dvxApplyColorScheme
.index dvxResetColorScheme
.index dvxLoadTheme
.index dvxSaveTheme
.index dvxColorName
.index dvxColorLabel
.index dvxSetWallpaper
.index dvxSetWallpaperMode
.index dvxSetMouseConfig
.index dvxCreateAccelTable
.index dvxFreeAccelTable
.index dvxAddAccel
.index dvxCascadeWindows
.index dvxTileWindows
.index dvxLoadImage
.index dvxFreeImage
.index dvxImageInfo
.index dvxSaveImage
.index dvxScreenshot
.index dvxWindowScreenshot
.index dvxClipboardCopy
.index dvxClipboardGet
.index dvxResLoadIcon
.index dvxResLoadText
.index dvxResLoadData
.index dvxTextHash
.index dvxChangeVideoMode

.h1 dvxApp.h -- Layer 5: Application API

The topmost layer and the public-facing API. Aggregates all lower layers into a single AppContextT. Applications interact exclusively through dvx*() functions and window callbacks. The event loop follows a cooperative model: poll, dispatch, composite, yield.

.h2 AppContextT

Single monolithic context that owns all GUI state. Contains the display, window stack, dirty list, blit ops, font, color scheme, popup state, cursor state, mouse/keyboard state, tooltip state, wallpaper buffer, video mode list, and various configuration fields. Allocated on the caller's stack or statically.

.h2 Initialization and Shutdown

.h3 dvxInit

.code
int32_t dvxInit(AppContextT *ctx, int32_t requestedW, int32_t requestedH, int32_t preferredBpp);
.endcode

Initialize the entire GUI stack: video mode, input devices, font, color scheme, cursor shapes, and internal state. Single entry point for starting a DVX application.

.table
  Parameter        Description
  ---------        -----------
  ctx              Application context to initialize
  requestedW/H     Desired screen resolution
  preferredBpp     Preferred bits per pixel
.endtable

Returns: 0 on success, negative on failure.

.h3 dvxShutdown

.code
void dvxShutdown(AppContextT *ctx);
.endcode

Tear down the GUI stack in reverse order: destroy all windows, restore text mode, release input devices. Safe to call after a failed dvxInit().

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
.endtable

.h3 dvxChangeVideoMode

.code
int32_t dvxChangeVideoMode(AppContextT *ctx, int32_t requestedW, int32_t requestedH, int32_t preferredBpp);
.endcode

Switch to a new video mode live. Reallocates the backbuffer, all window content buffers, repacks colors, rescales wallpaper, and repositions off-screen windows.

.table
  Parameter        Description
  ---------        -----------
  ctx              Application context
  requestedW/H     New resolution
  preferredBpp     New bits per pixel
.endtable

Returns: 0 on success, -1 on failure (old mode restored).

.h2 Event Loop

.h3 dvxRun

.code
void dvxRun(AppContextT *ctx);
.endcode

Enter the main event loop. Polls input, dispatches events, composites dirty regions, and yields on each iteration. Returns when ctx->running becomes false.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
.endtable

.h3 dvxUpdate

.code
bool dvxUpdate(AppContextT *ctx);
.endcode

Process exactly one frame of the event loop. For applications that integrate the GUI into their own main loop (e.g. polling serial ports between frames).

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
.endtable

Returns: false when the GUI wants to exit.

.h3 dvxQuit

.code
void dvxQuit(AppContextT *ctx);
.endcode

Request exit from the main event loop (sets ctx->running = false).

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
.endtable

.h2 Window Management

.h3 dvxCreateWindow

.code
WindowT *dvxCreateWindow(AppContextT *ctx, const char *title, int32_t x, int32_t y, int32_t w, int32_t h, bool resizable);
.endcode

Create a window at an explicit screen position. The window is raised to the top, focused, and its entire region is dirtied.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  title       Window title
  x, y        Screen position
  w, h        Outer frame dimensions
  resizable   true = allow user resize
.endtable

Returns: Pointer to new WindowT.

.h3 dvxCreateWindowCentered

.code
WindowT *dvxCreateWindowCentered(AppContextT *ctx, const char *title, int32_t w, int32_t h, bool resizable);
.endcode

Convenience wrapper that centers the window on screen.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  title       Window title
  w, h        Outer frame dimensions
  resizable   true = allow user resize
.endtable

Returns: Pointer to new WindowT.

.h3 dvxDestroyWindow

.code
void dvxDestroyWindow(AppContextT *ctx, WindowT *win);
.endcode

Destroy a window, free all its resources, and dirty its former region.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  win         Window to destroy
.endtable

.h3 dvxRaiseWindow

.code
void dvxRaiseWindow(AppContextT *ctx, WindowT *win);
.endcode

Raise a window to the top of the Z-order and give it focus.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  win         Window to raise
.endtable

.h3 dvxFitWindow

.code
void dvxFitWindow(AppContextT *ctx, WindowT *win);
.endcode

Resize a window to exactly fit its widget tree's computed minimum size (plus chrome). Used for dialog boxes and fixed-layout windows.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  win         Window to fit
.endtable

.h3 dvxFitWindowW

.code
void dvxFitWindowW(AppContextT *ctx, WindowT *win);
.endcode

Resize window width only to fit widget tree's minimum width (plus chrome).

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  win         Window to fit
.endtable

.h3 dvxFitWindowH

.code
void dvxFitWindowH(AppContextT *ctx, WindowT *win);
.endcode

Resize window height only to fit widget tree's minimum height (plus chrome).

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  win         Window to fit
.endtable

.h3 dvxResizeWindow

.code
void dvxResizeWindow(AppContextT *ctx, WindowT *win, int32_t newW, int32_t newH);
.endcode

Programmatically resize a window to the specified outer dimensions.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  win         Window to resize
  newW, newH  New outer frame dimensions
.endtable

.h3 dvxMinimizeWindow

.code
void dvxMinimizeWindow(AppContextT *ctx, WindowT *win);
.endcode

Minimize a window (show as icon at bottom of screen).

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  win         Window to minimize
.endtable

.h3 dvxMaximizeWindow

.code
void dvxMaximizeWindow(AppContextT *ctx, WindowT *win);
.endcode

Maximize a window (expand to fill screen or maxW/maxH).

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  win         Window to maximize
.endtable

.h3 dvxHideWindow

.code
void dvxHideWindow(AppContextT *ctx, WindowT *win);
.endcode

Hide a window without destroying it. Marks the exposed region dirty.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  win         Window to hide
.endtable

.h3 dvxShowWindow

.code
void dvxShowWindow(AppContextT *ctx, WindowT *win);
.endcode

Show a previously hidden window. Marks its region dirty for repaint.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  win         Window to show
.endtable

.h2 Invalidation

.h3 dvxInvalidateRect

.code
void dvxInvalidateRect(AppContextT *ctx, WindowT *win, int32_t x, int32_t y, int32_t w, int32_t h);
.endcode

Mark a sub-region of a window's content area as needing repaint. Coordinates are relative to the content area, not the screen. Triggers onPaint during the next composite pass.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  win         Window
  x, y, w, h Dirty rectangle in content-relative coordinates
.endtable

.h3 dvxInvalidateWindow

.code
void dvxInvalidateWindow(AppContextT *ctx, WindowT *win);
.endcode

Mark the entire window content area as dirty.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  win         Window to invalidate
.endtable

.h2 Window Properties

.h3 dvxSetTitle

.code
void dvxSetTitle(AppContextT *ctx, WindowT *win, const char *title);
.endcode

Set a window's title text and dirty the title bar.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  win         Window
  title       New title text
.endtable

.h3 dvxSetWindowIcon

.code
int32_t dvxSetWindowIcon(AppContextT *ctx, WindowT *win, const char *path);
.endcode

Load an icon for a window from an image file.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  win         Window
  path        Image file path
.endtable

Returns: 0 on success, -1 on failure.

.h3 dvxSetBusy

.code
void dvxSetBusy(AppContextT *ctx, bool busy);
.endcode

Set or clear busy state. While busy, the hourglass cursor is shown and input is blocked.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  busy        true = show hourglass, false = normal
.endtable

.h2 Accessors

.h3 dvxGetFont

.code
const BitmapFontT *dvxGetFont(const AppContextT *ctx);
.endcode

Get a pointer to the default font.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
.endtable

Returns: Pointer to the active BitmapFontT.

.h3 dvxGetColors

.code
const ColorSchemeT *dvxGetColors(const AppContextT *ctx);
.endcode

Get a pointer to the current color scheme.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
.endtable

Returns: Pointer to the active ColorSchemeT.

.h3 dvxGetDisplay

.code
DisplayT *dvxGetDisplay(AppContextT *ctx);
.endcode

Get a pointer to the display context.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
.endtable

Returns: Pointer to the DisplayT.

.h3 dvxGetBlitOps

.code
const BlitOpsT *dvxGetBlitOps(const AppContextT *ctx);
.endcode

Get a pointer to the blit operations vtable.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
.endtable

Returns: Pointer to the active BlitOpsT.

.h3 dvxGetVideoModes

.code
const VideoModeInfoT *dvxGetVideoModes(const AppContextT *ctx, int32_t *count);
.endcode

Return the list of available video modes enumerated at init time.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  count       Output: number of mode entries
.endtable

Returns: Pointer to the VideoModeInfoT array.

.h2 Color Scheme

.h3 dvxSetColor

.code
void dvxSetColor(AppContextT *ctx, ColorIdE id, uint8_t r, uint8_t g, uint8_t b);
.endcode

Set a single color by ID. Repacks to native pixel format and invalidates the entire screen.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  id          Color ID (ColorIdE)
  r, g, b     RGB values (0-255)
.endtable

.h3 dvxGetColor

.code
void dvxGetColor(const AppContextT *ctx, ColorIdE id, uint8_t *r, uint8_t *g, uint8_t *b);
.endcode

Get a color's RGB values by ID.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  id          Color ID (ColorIdE)
  r, g, b     Output: RGB values
.endtable

.h3 dvxApplyColorScheme

.code
void dvxApplyColorScheme(AppContextT *ctx);
.endcode

Apply all colors from ctx->colorRgb[] at once (repack + full repaint).

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
.endtable

.h3 dvxResetColorScheme

.code
void dvxResetColorScheme(AppContextT *ctx);
.endcode

Reset all colors to the built-in defaults and repaint.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
.endtable

.h3 dvxLoadTheme

.code
bool dvxLoadTheme(AppContextT *ctx, const char *filename);
.endcode

Load a theme file (INI format with [colors] section) and apply it.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  filename    Path to theme INI file
.endtable

Returns: true on success.

.h3 dvxSaveTheme

.code
bool dvxSaveTheme(const AppContextT *ctx, const char *filename);
.endcode

Save the current color scheme to a theme file.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  filename    Output file path
.endtable

Returns: true on success.

.h3 dvxColorName

.code
const char *dvxColorName(ColorIdE id);
.endcode

Return the INI key name for a color ID (e.g. "desktop", "windowFace").

.table
  Parameter   Description
  ---------   -----------
  id          Color ID
.endtable

Returns: Static string.

.h3 dvxColorLabel

.code
const char *dvxColorLabel(ColorIdE id);
.endcode

Return a human-readable display label (e.g. "Desktop", "Cursor Color").

.table
  Parameter   Description
  ---------   -----------
  id          Color ID
.endtable

Returns: Static string.

.h2 Wallpaper

.h3 dvxSetWallpaper

.code
bool dvxSetWallpaper(AppContextT *ctx, const char *path);
.endcode

Load and apply a wallpaper image using the current wallpaperMode (stretch/tile/center). Pass NULL to clear the wallpaper.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  path        Image file path, or NULL to clear
.endtable

Returns: true on success.

.h3 dvxSetWallpaperMode

.code
void dvxSetWallpaperMode(AppContextT *ctx, WallpaperModeE mode);
.endcode

Change the wallpaper display mode and re-render. No effect if no wallpaper is loaded.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  mode        WallpaperStretchE, WallpaperTileE, or WallpaperCenterE
.endtable

.h2 Mouse Configuration

.h3 dvxSetMouseConfig

.code
void dvxSetMouseConfig(AppContextT *ctx, int32_t wheelDir, int32_t dblClickMs, int32_t accelThreshold);
.endcode

Configure mouse behavior.

.table
  Parameter        Description
  ---------        -----------
  ctx              Application context
  wheelDir         1 = normal, -1 = reversed
  dblClickMs       Double-click speed in milliseconds (e.g. 500)
  accelThreshold   Double-speed threshold in mickeys/sec (0 = don't change)
.endtable

.h2 Accelerators

.h3 dvxCreateAccelTable

.code
AccelTableT *dvxCreateAccelTable(void);
.endcode

Allocate a new accelerator table. Attach to a window via win->accelTable.

Returns: Pointer to new AccelTableT.

.h3 dvxFreeAccelTable

.code
void dvxFreeAccelTable(AccelTableT *table);
.endcode

Free an accelerator table and its entries.

.table
  Parameter   Description
  ---------   -----------
  table       Table to free
.endtable

.h3 dvxAddAccel

.code
void dvxAddAccel(AccelTableT *table, int32_t key, int32_t modifiers, int32_t cmdId);
.endcode

Register a keyboard shortcut. On match, fires the window's onMenu callback with cmdId.

.table
  Parameter   Description
  ---------   -----------
  table       Accelerator table
  key         ASCII character or KEY_Fxx constant
  modifiers   Bitmask of ACCEL_CTRL / ACCEL_SHIFT / ACCEL_ALT
  cmdId       Command ID passed to onMenu
.endtable

.h2 Window Arrangement

.h3 dvxCascadeWindows

.code
void dvxCascadeWindows(AppContextT *ctx);
.endcode

Cascade all visible, non-minimized windows. Each is offset diagonally by the title bar height.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
.endtable

.h3 dvxTileWindows

.code
void dvxTileWindows(AppContextT *ctx);
.endcode

Arrange visible windows in an NxM grid filling the screen.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
.endtable

.h3 dvxTileWindowsH

.code
void dvxTileWindowsH(AppContextT *ctx);
.endcode

Tile windows horizontally (side by side, equal width, full height).

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
.endtable

.h3 dvxTileWindowsV

.code
void dvxTileWindowsV(AppContextT *ctx);
.endcode

Tile windows vertically (stacked, full width, equal height).

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
.endtable

.h2 Image I/O

.h3 dvxLoadImage

.code
uint8_t *dvxLoadImage(const AppContextT *ctx, const char *path, int32_t *outW, int32_t *outH, int32_t *outPitch);
.endcode

Load an image file (BMP, PNG, JPEG, GIF) and convert to the display's native pixel format. Caller must free with dvxFreeImage().

.table
  Parameter     Description
  ---------     -----------
  ctx           Application context
  path          Image file path
  outW, outH    Output: image dimensions
  outPitch      Output: row pitch in bytes
.endtable

Returns: Pixel buffer, or NULL on failure.

.h3 dvxLoadImageFromMemory

.code
uint8_t *dvxLoadImageFromMemory(const AppContextT *ctx, const uint8_t *data, int32_t dataLen, int32_t *outW, int32_t *outH, int32_t *outPitch);
.endcode

Load an image from a memory buffer. Same output format as dvxLoadImage(). Caller must free with dvxFreeImage().

.table
  Parameter     Description
  ---------     -----------
  ctx           Application context
  data          Image data buffer
  dataLen       Buffer size in bytes
  outW, outH    Output: image dimensions
  outPitch      Output: row pitch in bytes
.endtable

Returns: Pixel buffer, or NULL on failure.

.h3 dvxFreeImage

.code
void dvxFreeImage(uint8_t *data);
.endcode

Free a pixel buffer returned by dvxLoadImage() or dvxLoadImageFromMemory().

.table
  Parameter   Description
  ---------   -----------
  data        Buffer to free
.endtable

.h3 dvxImageInfo

.code
bool dvxImageInfo(const char *path, int32_t *outW, int32_t *outH);
.endcode

Query image dimensions without decoding the full file.

.table
  Parameter     Description
  ---------     -----------
  path          Image file path
  outW, outH    Output: image dimensions
.endtable

Returns: true on success.

.h3 dvxSaveImage

.code
int32_t dvxSaveImage(const AppContextT *ctx, const uint8_t *data, int32_t w, int32_t h, int32_t pitch, const char *path);
.endcode

Save native-format pixel data to a PNG file.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  data        Pixel data in display native format
  w, h        Image dimensions
  pitch       Row pitch in bytes
  path        Output file path
.endtable

Returns: 0 on success, -1 on failure.

.h2 Screenshots

.h3 dvxScreenshot

.code
int32_t dvxScreenshot(AppContextT *ctx, const char *path);
.endcode

Save the entire screen (backbuffer contents) to a PNG file. Converts from native pixel format to RGB.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  path        Output PNG file path
.endtable

Returns: 0 on success, -1 on failure.

.h3 dvxWindowScreenshot

.code
int32_t dvxWindowScreenshot(AppContextT *ctx, WindowT *win, const char *path);
.endcode

Save a window's content to a PNG file.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  win         Window
  path        Output PNG file path
.endtable

Returns: 0 on success, -1 on failure.

.h2 Clipboard

.h3 dvxClipboardCopy

.code
void dvxClipboardCopy(const char *text, int32_t len);
.endcode

Copy text to the process-wide clipboard buffer. Simple static buffer (not inter-process).

.table
  Parameter   Description
  ---------   -----------
  text        Text to copy
  len         Length in bytes
.endtable

.h3 dvxClipboardGet

.code
const char *dvxClipboardGet(int32_t *outLen);
.endcode

Retrieve the current clipboard contents. Returns a pointer to the internal buffer (valid until the next dvxClipboardCopy), or NULL if empty.

.table
  Parameter   Description
  ---------   -----------
  outLen      Output: length of clipboard text
.endtable

Returns: Clipboard text, or NULL.

.h2 Resource Loading

.h3 dvxResLoadIcon

.code
uint8_t *dvxResLoadIcon(AppContextT *ctx, const char *dxePath, const char *resName, int32_t *outW, int32_t *outH, int32_t *outPitch);
.endcode

Load an icon/image resource from a DXE file and decode to native pixel format. Caller must free with dvxFreeImage().

.table
  Parameter     Description
  ---------     -----------
  ctx           Application context
  dxePath       Path to DXE file
  resName       Resource name within the DXE
  outW, outH    Output: image dimensions
  outPitch      Output: row pitch
.endtable

Returns: Pixel buffer, or NULL if not found.

.h3 dvxResLoadText

.code
bool dvxResLoadText(const char *dxePath, const char *resName, char *buf, int32_t bufSize);
.endcode

Load a text resource from a DXE file into a caller-provided buffer. Null-terminated and truncated to fit bufSize.

.table
  Parameter   Description
  ---------   -----------
  dxePath     Path to DXE file
  resName     Resource name
  buf         Output buffer
  bufSize     Buffer capacity
.endtable

Returns: true on success.

.h3 dvxResLoadData

.code
void *dvxResLoadData(const char *dxePath, const char *resName, uint32_t *outSize);
.endcode

Load a raw binary resource from a DXE file. Returns a malloc'd buffer that the caller must free.

.table
  Parameter   Description
  ---------   -----------
  dxePath     Path to DXE file
  resName     Resource name
  outSize     Output: data size in bytes
.endtable

Returns: Data buffer, or NULL if not found.

.h2 Utilities

.h3 dvxTextHash

.code
uint32_t dvxTextHash(const char *text);
.endcode

Compute a djb2-xor hash for cheap dirty detection. Compare at save time with the current hash to detect changes without a shadow copy. Not cryptographic.

.table
  Parameter   Description
  ---------   -----------
  text        Null-terminated string to hash
.endtable

Returns: 32-bit hash value.

.topic api.widget
.title dvxWidget.h -- Widget System
.toc 1 dvxWidget.h -- Widget System
.index dvxWidget.h
.index WidgetT
.index WidgetClassT
.index wgtInitWindow
.index wgtGetContext
.index wgtInvalidate
.index wgtInvalidatePaint
.index wgtSetText
.index wgtGetText
.index wgtSetEnabled
.index wgtSetReadOnly
.index wgtSetFocused
.index wgtGetFocused
.index wgtSetVisible
.index wgtSetName
.index wgtFind
.index wgtDestroy
.index wgtSetTooltip
.index wgtResolveSize
.index wgtLayout
.index wgtPaint
.index wgtSetDebugLayout
.index wgtRegisterClass
.index wgtRegisterApi
.index wgtGetApi
.index wgtRegisterIface
.index wgtGetIface
.index wgtFindByBasName
.index wgtPixels
.index wgtChars
.index wgtPercent

.h1 dvxWidget.h -- Widget System

Retained-mode widget toolkit layered on the DVX window manager. Widgets form a tree (parent-child) rooted at a per-window VBox container. Layout is automatic: measure minimum sizes bottom-up, then allocate space top-down with flexbox-like weighted distribution. Widget types are registered dynamically at runtime via DXE plugins.

.h2 WidgetT Structure

Core widget structure. Generic across all widget types; type-specific data lives in the void *data pointer managed by each widget's DXE.

.table
  Field                                       Description
  -----                                       -----------
  int32_t type                                Widget type ID (assigned by wgtRegisterClass)
  const WidgetClassT *wclass                  Vtable for this widget type
  char name[MAX_WIDGET_NAME]                  Widget name for lookup via wgtFind
  parent, firstChild, lastChild, nextSibling  Tree linkage pointers
  WindowT *window                             Owning window
  int32_t x, y, w, h                         Computed geometry (relative to content area)
  int32_t calcMinW, calcMinH                  Computed minimum size (from layout pass)
  int32_t minW, minH, maxW, maxH, prefW, prefH  Size hints (tagged sizes)
  int32_t weight                              Extra-space distribution weight (0=fixed, 100=normal)
  WidgetAlignE align                          Main-axis alignment for children
  int32_t spacing, padding                    Tagged sizes for child spacing and padding
  uint32_t fgColor, bgColor                   Custom colors (0 = use scheme defaults)
  bool visible, enabled, readOnly             State flags
  bool swallowTab                             Tab key goes to widget, not focus navigation
  char accelKey                               Accelerator character (0 = none)
  void *userData, *data                       Application data and widget-private data
  const char *tooltip                         Tooltip text (NULL = none)
  MenuT *contextMenu                          Right-click menu (NULL = none)
.endtable

Universal Callbacks:

.table
  Callback                                           Description
  --------                                           -----------
  onClick(WidgetT *w)                                Widget clicked
  onDblClick(WidgetT *w)                             Widget double-clicked
  onChange(WidgetT *w)                               Value changed
  onFocus(WidgetT *w)                                Widget gained focus
  onBlur(WidgetT *w)                                 Widget lost focus
  onKeyPress(WidgetT *w, int32_t keyAscii)           ASCII key press
  onKeyDown(WidgetT *w, int32_t keyCode, int32_t shift)  Key down
  onKeyUp(WidgetT *w, int32_t keyCode, int32_t shift)    Key up
  onMouseDown(WidgetT *w, int32_t btn, int32_t x, int32_t y)  Mouse button pressed
  onMouseUp(WidgetT *w, int32_t btn, int32_t x, int32_t y)    Mouse button released
  onMouseMove(WidgetT *w, int32_t btn, int32_t x, int32_t y)  Mouse moved
  onScroll(WidgetT *w, int32_t delta)                Mouse wheel
  onValidate(WidgetT *w)                             Return false to cancel a write
.endtable

.h2 Size Specification Macros

.table
  Macro            Description
  -----            -----------
  wgtPixels(v)     Size in pixels
  wgtChars(v)      Size in character widths (multiplied by charWidth at layout)
  wgtPercent(v)    Size as percentage of parent dimension
.endtable

.h2 Widget Class Flags

.table
  Flag                        Description
  ----                        -----------
  WCLASS_FOCUSABLE            Can receive keyboard focus (Tab navigation)
  WCLASS_HORIZ_CONTAINER      Lays out children horizontally (vs. vertical)
  WCLASS_PAINTS_CHILDREN      Widget handles child rendering itself
  WCLASS_NO_HIT_RECURSE       Hit testing stops here, no child recursion
  WCLASS_FOCUS_FORWARD        Accel hit forwards focus to next focusable sibling
  WCLASS_HAS_POPUP            Has dropdown popup overlay
  WCLASS_SCROLLABLE           Accepts mouse wheel events
  WCLASS_SCROLL_CONTAINER     Scroll container (ScrollPane)
  WCLASS_NEEDS_POLL           Needs periodic polling
  WCLASS_SWALLOWS_TAB         Tab key goes to widget, not focus navigation
  WCLASS_RELAYOUT_ON_SCROLL   Full relayout on scrollbar drag
  WCLASS_PRESS_RELEASE        Click = press + release (Button, ImageButton)
  WCLASS_ACCEL_WHEN_HIDDEN    Accelerator matching works even when invisible
.endtable

.h2 Window Integration

.h3 wgtInitWindow

.code
WidgetT *wgtInitWindow(AppContextT *ctx, WindowT *win);
.endcode

Initialize the widget system for a window. Creates a root VBox container that fills the content area, and installs callback handlers (onPaint, onMouse, onKey, onResize) for widget-based event dispatch. The window's userData is set to the AppContextT pointer.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  win         Window to initialize
.endtable

Returns: Root VBox widget (add children to this).

.h2 Widget Operations

.h3 wgtGetContext

.code
AppContextT *wgtGetContext(const WidgetT *w);
.endcode

Walk from any widget up the tree to the root, then retrieve the AppContextT stored in the window's userData. Lets any widget access the full application context.

.table
  Parameter   Description
  ---------   -----------
  w           Any widget in the tree
.endtable

Returns: Pointer to the AppContextT.

.h3 wgtInvalidate

.code
void wgtInvalidate(WidgetT *w);
.endcode

Mark a widget as needing both re-layout (measure + position) and repaint. Propagates upward to ancestors. Use after structural changes (adding/removing children, text changes that affect size).

.table
  Parameter   Description
  ---------   -----------
  w           Widget to invalidate
.endtable

.h3 wgtInvalidatePaint

.code
void wgtInvalidatePaint(WidgetT *w);
.endcode

Mark a widget as needing repaint only, without re-layout. Use for visual-only changes (checkbox toggle, selection highlight, cursor blink).

.table
  Parameter   Description
  ---------   -----------
  w           Widget to repaint
.endtable

.h3 wgtSetText

.code
void wgtSetText(WidgetT *w, const char *text);
.endcode

Set widget text content (dispatches to the widget class's SET_TEXT handler).

.table
  Parameter   Description
  ---------   -----------
  w           Widget
  text        New text
.endtable

.h3 wgtGetText

.code
const char *wgtGetText(const WidgetT *w);
.endcode

Get the widget's current text content.

.table
  Parameter   Description
  ---------   -----------
  w           Widget
.endtable

Returns: Text string (empty string if no handler).

.h3 wgtSetEnabled

.code
void wgtSetEnabled(WidgetT *w, bool enabled);
.endcode

Enable or disable a widget. Disabled widgets are grayed out and do not receive input.

.table
  Parameter   Description
  ---------   -----------
  w           Widget
  enabled     true = enabled, false = disabled
.endtable

.h3 wgtSetReadOnly

.code
void wgtSetReadOnly(WidgetT *w, bool readOnly);
.endcode

Set read-only mode. Allows scrolling and selection but blocks editing.

.table
  Parameter   Description
  ---------   -----------
  w           Widget
  readOnly    true = read-only
.endtable

.h3 wgtSetFocused

.code
void wgtSetFocused(WidgetT *w);
.endcode

Set keyboard focus to a widget.

.table
  Parameter   Description
  ---------   -----------
  w           Widget to focus
.endtable

.h3 wgtGetFocused

.code
WidgetT *wgtGetFocused(void);
.endcode

Get the currently focused widget.

Returns: Focused widget, or NULL.

.h3 wgtSetVisible

.code
void wgtSetVisible(WidgetT *w, bool visible);
.endcode

Show or hide a widget.

.table
  Parameter   Description
  ---------   -----------
  w           Widget
  visible     true = visible, false = hidden
.endtable

.h3 wgtSetName

.code
void wgtSetName(WidgetT *w, const char *name);
.endcode

Set a widget's name for lookup via wgtFind().

.table
  Parameter   Description
  ---------   -----------
  w           Widget
  name        Name string (max MAX_WIDGET_NAME chars)
.endtable

.h3 wgtFind

.code
WidgetT *wgtFind(WidgetT *root, const char *name);
.endcode

Find a widget by name. Searches the subtree rooted at root.

.table
  Parameter   Description
  ---------   -----------
  root        Root of subtree to search
  name        Widget name to find
.endtable

Returns: Matching widget, or NULL.

.h3 wgtDestroy

.code
void wgtDestroy(WidgetT *w);
.endcode

Destroy a widget and all its children. Removes from parent's child list.

.table
  Parameter   Description
  ---------   -----------
  w           Widget to destroy
.endtable

.h3 wgtSetTooltip

.code
void wgtSetTooltip(WidgetT *w, const char *text);
.endcode

Set tooltip text for a widget. Pass NULL to remove. Caller owns the string and it must outlive the widget.

.table
  Parameter   Description
  ---------   -----------
  w           Widget
  text        Tooltip text, or NULL
.endtable

.h3 widgetOnResize

.code
void widgetOnResize(WindowT *win, int32_t newW, int32_t newH);
.endcode

Default window resize handler installed by wgtInitWindow(). Re-evaluates scrollbars and relayouts the widget tree. Call from custom onResize handlers to chain to the widget system.

.table
  Parameter    Description
  ---------    -----------
  win          Window being resized
  newW, newH   New content dimensions
.endtable

.h2 Layout

.h3 wgtResolveSize

.code
int32_t wgtResolveSize(int32_t taggedSize, int32_t parentSize, int32_t charWidth);
.endcode

Decode a tagged size value (WGT_SIZE_PIXELS/CHARS/PERCENT) into a concrete pixel count. Returns 0 for a raw 0 input (meaning "auto").

.table
  Parameter     Description
  ---------     -----------
  taggedSize    Tagged size value
  parentSize    Parent dimension (for PERCENT mode)
  charWidth     Font character width (for CHARS mode)
.endtable

Returns: Size in pixels.

.h3 wgtLayout

.code
void wgtLayout(WidgetT *root, int32_t availW, int32_t availH, const BitmapFontT *font);
.endcode

Execute the full two-pass layout algorithm. Pass 1 (bottom-up): compute minimum sizes. Pass 2 (top-down): allocate space with weighted distribution. Normally called automatically; exposed for cases where layout must be forced before the next paint.

.table
  Parameter     Description
  ---------     -----------
  root          Root widget
  availW/H      Available space
  font          Bitmap font (for character-based sizing)
.endtable

.h3 wgtPaint

.code
void wgtPaint(WidgetT *root, DisplayT *d, const BlitOpsT *ops, const BitmapFontT *font, const ColorSchemeT *colors);
.endcode

Paint the entire widget tree by depth-first traversal. Each widget's clip rect is set to its bounds. Overlays (popups, tooltips) are painted in a second pass on top.

.table
  Parameter   Description
  ---------   -----------
  root        Root widget
  d           Display context
  ops         Blit operations vtable
  font        Bitmap font
  colors      Color scheme
.endtable

.h2 Debug

.h3 wgtSetDebugLayout

.code
void wgtSetDebugLayout(AppContextT *ctx, bool enabled);
.endcode

Draw colored borders around layout containers for debugging.

.table
  Parameter   Description
  ---------   -----------
  ctx         Application context
  enabled     true = draw debug borders
.endtable

.h2 Dynamic Widget Registration

.h3 wgtRegisterClass

.code
int32_t wgtRegisterClass(const WidgetClassT *wclass);
.endcode

Register a new widget class at runtime. Appends to widgetClassTable. The WidgetClassT must remain valid for the lifetime of the process (typically static const in a DXE).

.table
  Parameter   Description
  ---------   -----------
  wclass      Widget class vtable to register
.endtable

Returns: Assigned type ID.

.h3 wgtRegisterApi

.code
void wgtRegisterApi(const char *name, const void *api);
.endcode

Register a widget API struct under a name. Each widget DXE registers its API during initialization. Callers retrieve it via wgtGetApi() and cast to the widget-specific type.

.table
  Parameter   Description
  ---------   -----------
  name        Widget type name (e.g. "button", "listbox")
  api         Pointer to the widget's API struct
.endtable

.h3 wgtGetApi

.code
const void *wgtGetApi(const char *name);
.endcode

Retrieve a registered widget API struct by name.

.table
  Parameter   Description
  ---------   -----------
  name        Widget type name
.endtable

Returns: Pointer to the API struct, or NULL if not found.

.h2 Widget Interface Descriptors

.h3 wgtRegisterIface

.code
void wgtRegisterIface(const char *name, const WgtIfaceT *iface);
.endcode

Register an interface descriptor for a widget type. Used by the BASIC form runtime and IDE for generic property/method dispatch.

.table
  Parameter   Description
  ---------   -----------
  name        Widget type name
  iface       Interface descriptor
.endtable

.h3 wgtGetIface

.code
const WgtIfaceT *wgtGetIface(const char *name);
.endcode

Retrieve an interface descriptor by widget type name.

.table
  Parameter   Description
  ---------   -----------
  name        Widget type name
.endtable

Returns: Interface descriptor, or NULL.

.h3 wgtFindByBasName

.code
const char *wgtFindByBasName(const char *basName);
.endcode

Find a widget type name by its VB-style name (e.g. "CommandButton" -> "button"). Case-insensitive search.

.table
  Parameter   Description
  ---------   -----------
  basName     VB-style widget name
.endtable

Returns: Internal type name, or NULL.

.h3 wgtIfaceCount

.code
int32_t wgtIfaceCount(void);
.endcode

Return the number of registered widget interfaces.

Returns: Count of registered interfaces.

.h3 wgtIfaceAt

.code
const WgtIfaceT *wgtIfaceAt(int32_t idx, const char **outName);
.endcode

Get a registered widget interface by index.

.table
  Parameter   Description
  ---------   -----------
  idx         Index (0-based)
  outName     Output: type name
.endtable

Returns: Interface descriptor.

.h3 wgtIfaceGetPath

.code
const char *wgtIfaceGetPath(const char *name);
.endcode

Get the .wgt DXE file path for a registered widget.

.table
  Parameter   Description
  ---------   -----------
  name        Widget type name
.endtable

Returns: File path string.

.h3 wgtIfaceSetPath

.code
void wgtIfaceSetPath(const char *name, const char *path);
.endcode

Set the .wgt DXE file path for a registered widget (called by the loader).

.table
  Parameter   Description
  ---------   -----------
  name        Widget type name
  path        DXE file path
.endtable

.h3 wgtIfaceGetPathIndex

.code
int32_t wgtIfaceGetPathIndex(const char *name);
.endcode

Get the 1-based index of this widget within its .wgt file. Used to construct suffixed resource names (e.g. "name-2", "icon16-2").

.table
  Parameter   Description
  ---------   -----------
  name        Widget type name
.endtable

Returns: 1-based index within the DXE file.

.h2 Typed Dispatch Helpers

The following inline functions provide type-safe dispatch through the WidgetClassT handler table. Each checks for a non-NULL handler before calling.

.table
  Function                                Method ID                          Description
  --------                                ---------                          -----------
  wclsHas(w, methodId)                    --                                 Check if handler exists
  wclsPaint(w, d, ops, font, colors)      WGT_METHOD_PAINT                   Paint the widget
  wclsPaintOverlay(w, d, ops, font, colors) WGT_METHOD_PAINT_OVERLAY         Paint overlay (popups)
  wclsCalcMinSize(w, font)                WGT_METHOD_CALC_MIN_SIZE           Compute minimum size
  wclsLayout(w, font)                     WGT_METHOD_LAYOUT                  Layout children
  wclsGetLayoutMetrics(w, font, ...)      WGT_METHOD_GET_LAYOUT_METRICS      Get pad, gap, extraTop, borderW
  wclsOnMouse(w, root, vx, vy)           WGT_METHOD_ON_MOUSE                Handle mouse event
  wclsOnKey(w, key, mod)                  WGT_METHOD_ON_KEY                  Handle key event
  wclsOnAccelActivate(w, root)            WGT_METHOD_ON_ACCEL_ACTIVATE       Handle accelerator
  wclsDestroy(w)                          WGT_METHOD_DESTROY                 Destroy widget data
  wclsOnChildChanged(parent, child)       WGT_METHOD_ON_CHILD_CHANGED        Notify parent of change
  wclsGetText(w)                          WGT_METHOD_GET_TEXT                Get widget text
  wclsSetText(w, text)                    WGT_METHOD_SET_TEXT                Set widget text
  wclsClearSelection(w)                   WGT_METHOD_CLEAR_SELECTION         Clear text selection
  wclsClosePopup(w)                       WGT_METHOD_CLOSE_POPUP             Close dropdown popup
  wclsGetPopupRect(w, font, ...)          WGT_METHOD_GET_POPUP_RECT          Get popup screen rect
  wclsOnDragUpdate(w, root, x, y)         WGT_METHOD_ON_DRAG_UPDATE          Update during drag
  wclsOnDragEnd(w, root, x, y)            WGT_METHOD_ON_DRAG_END             End drag operation
  wclsGetCursorShape(w, vx, vy)           WGT_METHOD_GET_CURSOR_SHAPE        Get cursor for position
  wclsPoll(w, win)                        WGT_METHOD_POLL                    Periodic polling
  wclsQuickRepaint(w, outY, outH)         WGT_METHOD_QUICK_REPAINT           Fast partial repaint
  wclsScrollChildIntoView(parent, child)  WGT_METHOD_SCROLL_CHILD_INTO_VIEW  Scroll child visible
.endtable
