// Drawing primitives.
//
// All primitives clip to the surface rectangle. Out-of-bounds draws are
// silent no-ops, not errors. samplePixel returns 0 for off-surface reads.
// Primitives operate on color indices; per-scanline palette resolution
// happens only at display time.

#ifndef JOEYLIB_DRAW_H
#define JOEYLIB_DRAW_H

#include "asset.h"
#include "platform.h"
#include "surface.h"
#include "types.h"

// Fill the entire surface with a single color index. Writes color 0 is
// a legitimate clear-to-black and does not skip.
void surfaceClear(SurfaceT *s, uint8_t colorIndex);

// Plot a single pixel. Off-surface coordinates are no-ops.
void drawPixel(SurfaceT *s, int16_t x, int16_t y, uint8_t colorIndex);

// Read a pixel value. Off-surface coordinates return 0.
uint8_t samplePixel(const SurfaceT *s, int16_t x, int16_t y);

// Plot a line from (x0, y0) to (x1, y1) using Bresenham. Endpoints
// are inclusive. Off-surface pixels are skipped per-pixel; lines that
// pass entirely off-surface draw nothing. Horizontal and vertical
// runs hit fast paths.
void drawLine(SurfaceT *s, int16_t x0, int16_t y0, int16_t x1, int16_t y1, uint8_t colorIndex);

// Outline a rectangle (1-pixel-wide border). 1xN / Nx1 degenerate
// to vertical / horizontal lines; 1x1 to a single pixel. Negative or
// zero dimensions are no-ops.
void drawRect(SurfaceT *s, int16_t x, int16_t y, uint16_t w, uint16_t h, uint8_t colorIndex);

// Fill a solid rectangle. Negative or zero dimensions are no-ops.
void fillRect(SurfaceT *s, int16_t x, int16_t y, uint16_t w, uint16_t h, uint8_t colorIndex);

// Outline a circle of radius r centered at (cx, cy) using Bresenham
// midpoint. r == 0 plots a single pixel.
void drawCircle(SurfaceT *s, int16_t cx, int16_t cy, uint16_t r, uint8_t colorIndex);

// Fill a disk of radius r centered at (cx, cy). r == 0 plots a single
// pixel. Spans are emitted per scanline using midpoint symmetry.
void fillCircle(SurfaceT *s, int16_t cx, int16_t cy, uint16_t r, uint8_t colorIndex);

// Flood fill a 4-connected region starting at (x, y). Replaces every
// pixel of the original color reached via N/S/E/W steps. No-op if
// (x, y) is off-surface or already matches newColor.
void floodFill(SurfaceT *s, int16_t x, int16_t y, uint8_t newColor);

// Flood fill a 4-connected region starting at (x, y), stopping at
// boundary pixels of color boundaryColor. Replaces every reachable
// pixel that is not boundaryColor with newColor. Used for vector-art
// rendering (e.g. Sierra-style picture playback): outline a closed
// region with drawLine in boundaryColor, then fill with this.
void floodFillBounded(SurfaceT *s, int16_t x, int16_t y, uint8_t newColor, uint8_t boundaryColor);

// Blit an asset onto the surface at (x, y). Source nibbles overwrite
// destination nibbles verbatim -- the caller is responsible for
// matching the asset's palette to the destination palette (typically
// via joeyAssetApplyPalette). Clipped to the surface; off-surface
// rows / columns are skipped.
void surfaceBlit(SurfaceT *dst, const JoeyAssetT *src, int16_t x, int16_t y);

// Like surfaceBlit, but source pixels equal to transparentIndex are
// skipped, leaving the destination pixel unchanged at that position.
// The standard convention is transparentIndex = 0.
void surfaceBlitMasked(SurfaceT *dst, const JoeyAssetT *src, int16_t x, int16_t y, uint8_t transparentIndex);

#endif