Function GfxFillRect

src/gfx.cpp:115–161

* Applies a certain FillRectMode-operation to a rectangle [left, right] x [top, bottom] on the screen. * * @pre dpi->zoom == ZoomLevel::Min, right >= left, bottom >= top * @param left Minimum X (inclusive) * @param top Minimum Y (inclusive) * @param right Maximum X (inclusive) * @param bottom Maximum Y (inclusive) * @param colour A 8 bit palette index (FILLRECT_OPAQUE and FILLRECT_CHECKER)

 *         FILLRECT_RECOLOUR:  Apply a recolour sprite to every pixel in the rectangle currently on screen
 */
void GfxFillRect(int left, int top, int right, int bottom, const std::variant<PixelColour, PaletteID> &colour, FillRectMode mode)
{
	Blitter *blitter = BlitterFactory::GetCurrentBlitter();
	const DrawPixelInfo *dpi = _cur_dpi;
	void *dst;
	const int otop = top;
	const int oleft = left;

	if (dpi->zoom != ZoomLevel::Min) return;
	if (left > right || top > bottom) return;
	if (right < dpi->left || left >= dpi->left + dpi->width) return;
	if (bottom < dpi->top || top >= dpi->top + dpi->height) return;

	if ( (left -= dpi->left) < 0) left = 0;
	right = right - dpi->left + 1;
	if (right > dpi->width) right = dpi->width;
	right -= left;
	assert(right > 0);

	if ( (top -= dpi->top) < 0) top = 0;
	bottom = bottom - dpi->top + 1;
	if (bottom > dpi->height) bottom = dpi->height;
	bottom -= top;
	assert(bottom > 0);

	dst = blitter->MoveTo(dpi->dst_ptr, left, top);

	switch (mode) {
		default: // FILLRECT_OPAQUE
			blitter->DrawRect(dst, right, bottom, std::get<PixelColour>(colour));
			break;

		case FILLRECT_RECOLOUR:
			blitter->DrawColourMappingRect(dst, right, bottom, GB(std::get<PaletteID>(colour), 0, PALETTE_WIDTH));
			break;

		case FILLRECT_CHECKER: {
			uint8_t bo = (oleft - left + dpi->left + otop - top + dpi->top) & 1;
			PixelColour pc = std::get<PixelColour>(colour);
			do {
				for (int i = (bo ^= 1); i < right; i += 2) blitter->SetPixel(dst, i, 0, pc);
				dst = blitter->MoveTo(dst, 0, 1);
			} while (--bottom > 0);
			break;
		}
	}
}

typedef std::pair<Point, Point> LineSegment;