Method ToneBlit

src/bitmap.cpp:859–1012

}

void Bitmap::ToneBlit(int x, int y, Bitmap const& src, Rect const& src_rect, const Tone &tone, Opacity const& opacity) {
	if (opacity.IsTransparent()) {
		return;
	}

	// Optimisations based on Opacity:
	// Transparent: Nothing to do
	// Opaque: Alpha check can be skipped
	// 1 Bit: Premultiplied Alpha can be skipped
	// 8 Bit: No optimisations possible

	auto src_opacity = src.GetImageOpacity();

	if (src_opacity == ImageOpacity::Transparent) {
		return;
	}

	if (tone == Tone(128,128,128,128)) {
		if (&src != this) {
			Blit(x, y, src, src_rect, opacity);
		}
		return;
	}

	// Only needed here, other codepaths are sanity checked by pixman
	if (x < 0 || y < 0 || x >= width() || y >= height()) {
		return;
	}

	if (&src != this) {
		pixman_image_composite32(src.GetOperator(),
		src.bitmap.get(), nullptr, bitmap.get(),
		src_rect.x, src_rect.y,
		0, 0,
		x, y,
		src_rect.width, src_rect.height);
	}

	const int as = pixel_format.a.shift;
	const int rs = pixel_format.r.shift;
	const int gs = pixel_format.g.shift;
	const int bs = pixel_format.b.shift;
	int next_row = pitch() / sizeof(uint32_t);
	uint32_t* pixels = (uint32_t*)this->pixels();
	pixels = pixels + (y - 1) * next_row + x;

	const uint16_t limit_height = std::min<uint16_t>(src_rect.height, height());
	const uint16_t limit_width = std::min<uint16_t>(src_rect.width, width());

	const bool apply_sat = tone.gray != 128;
	const bool apply_tone = (tone.red != 128 || tone.green != 128 || tone.blue != 128);

	// If Saturation + Color:
	if (apply_sat && apply_tone) {
		int sat = tone.gray > 128 ? 1024 + (tone.gray - 128) * 16 : tone.gray * 8;

		if (src_opacity == ImageOpacity::Opaque) {
			for (uint16_t i = 0; i < limit_height; ++i) {