DVX_GUI/dvx/widgets/widgetCore.c

// widgetCore.c — Core widget infrastructure (alloc, tree ops, helpers)

#include "widgetInternal.h"

// ============================================================
// Global state for drag and popup tracking
// ============================================================

bool     sDebugLayout   = false;
WidgetT *sOpenPopup     = NULL;
WidgetT *sDragSlider    = NULL;
WidgetT *sDrawingCanvas = NULL;
int32_t  sDragOffset    = 0;


// ============================================================
// widgetAddChild
// ============================================================

void widgetAddChild(WidgetT *parent, WidgetT *child) {
    child->parent      = parent;
    child->nextSibling = NULL;

    if (parent->lastChild) {
        parent->lastChild->nextSibling = child;
        parent->lastChild = child;
    } else {
        parent->firstChild = child;
        parent->lastChild  = child;
    }
}


// ============================================================
// widgetAlloc
// ============================================================

WidgetT *widgetAlloc(WidgetT *parent, WidgetTypeE type) {
    WidgetT *w = (WidgetT *)malloc(sizeof(WidgetT));

    if (!w) {
        return NULL;
    }

    memset(w, 0, sizeof(*w));
    w->type    = type;
    w->visible = true;
    w->enabled = true;

    if (parent) {
        w->window = parent->window;
        widgetAddChild(parent, w);
    }

    return w;
}


// ============================================================
// widgetCountVisibleChildren
// ============================================================

int32_t widgetCountVisibleChildren(const WidgetT *w) {
    int32_t count = 0;

    for (const WidgetT *c = w->firstChild; c; c = c->nextSibling) {
        if (c->visible) {
            count++;
        }
    }

    return count;
}


// ============================================================
// widgetDestroyChildren
// ============================================================

void widgetDestroyChildren(WidgetT *w) {
    WidgetT *child = w->firstChild;

    while (child) {
        WidgetT *next = child->nextSibling;
        widgetDestroyChildren(child);

        if (child->type == WidgetTextInputE) {
            free(child->as.textInput.buf);
        } else if (child->type == WidgetTextAreaE) {
            free(child->as.textArea.buf);
        } else if (child->type == WidgetComboBoxE) {
            free(child->as.comboBox.buf);
        } else if (child->type == WidgetImageE) {
            free(child->as.image.data);
        } else if (child->type == WidgetCanvasE) {
            free(child->as.canvas.data);
        }

        // Clear popup/drag references if they point to destroyed widgets
        if (sOpenPopup == child) {
            sOpenPopup = NULL;
        }

        if (sDragSlider == child) {
            sDragSlider = NULL;
        }

        if (sDrawingCanvas == child) {
            sDrawingCanvas = NULL;
        }

        free(child);
        child = next;
    }

    w->firstChild = NULL;
    w->lastChild  = NULL;
}


// ============================================================
// widgetDropdownPopupRect
// ============================================================
//
// Calculate the rectangle for a dropdown/combobox popup list.

void widgetDropdownPopupRect(WidgetT *w, const BitmapFontT *font, int32_t contentH, int32_t *popX, int32_t *popY, int32_t *popW, int32_t *popH) {
    int32_t itemCount = 0;

    if (w->type == WidgetDropdownE) {
        itemCount = w->as.dropdown.itemCount;
    } else if (w->type == WidgetComboBoxE) {
        itemCount = w->as.comboBox.itemCount;
    }

    int32_t visibleItems = itemCount;

    if (visibleItems > DROPDOWN_MAX_VISIBLE) {
        visibleItems = DROPDOWN_MAX_VISIBLE;
    }

    if (visibleItems < 1) {
        visibleItems = 1;
    }

    *popX = w->x;
    *popW = w->w;
    *popH = visibleItems * font->charHeight + 4; // 2px border each side

    // Try below first, then above if no room
    if (w->y + w->h + *popH <= contentH) {
        *popY = w->y + w->h;
    } else {
        *popY = w->y - *popH;

        if (*popY < 0) {
            *popY = 0;
        }
    }
}


// ============================================================
// widgetFrameBorderWidth
// ============================================================

int32_t widgetFrameBorderWidth(const WidgetT *w) {
    if (w->type != WidgetFrameE) {
        return 0;
    }

    if (w->as.frame.style == FrameFlatE) {
        return FRAME_FLAT_BORDER;
    }

    return FRAME_BEVEL_BORDER;
}


// ============================================================
// widgetHitTest
// ============================================================

WidgetT *widgetHitTest(WidgetT *w, int32_t x, int32_t y) {
    if (!w->visible) {
        return NULL;
    }

    if (x < w->x || x >= w->x + w->w || y < w->y || y >= w->y + w->h) {
        return NULL;
    }

    // Check children — take the last match (topmost in Z-order)
    WidgetT *hit = NULL;

    for (WidgetT *c = w->firstChild; c; c = c->nextSibling) {
        WidgetT *childHit = widgetHitTest(c, x, y);

        if (childHit) {
            hit = childHit;
        }
    }

    return hit ? hit : w;
}


// ============================================================
// widgetIsBoxContainer
// ============================================================
//
// Returns true for widget types that use the generic box layout.

bool widgetIsBoxContainer(WidgetTypeE type) {
    return type == WidgetVBoxE || type == WidgetHBoxE || type == WidgetFrameE ||
           type == WidgetRadioGroupE || type == WidgetTabPageE ||
           type == WidgetStatusBarE || type == WidgetToolbarE;
}


// ============================================================
// widgetIsHorizContainer
// ============================================================
//
// Returns true for container types that lay out children horizontally.

bool widgetIsHorizContainer(WidgetTypeE type) {
    return type == WidgetHBoxE || type == WidgetStatusBarE || type == WidgetToolbarE;
}


// ============================================================
// widgetRemoveChild
// ============================================================

void widgetRemoveChild(WidgetT *parent, WidgetT *child) {
    WidgetT *prev = NULL;

    for (WidgetT *c = parent->firstChild; c; c = c->nextSibling) {
        if (c == child) {
            if (prev) {
                prev->nextSibling = c->nextSibling;
            } else {
                parent->firstChild = c->nextSibling;
            }

            if (parent->lastChild == child) {
                parent->lastChild = prev;
            }

            child->nextSibling = NULL;
            child->parent      = NULL;
            return;
        }

        prev = c;
    }
}