Backport: Extract image conversion from RGBA to BGRA premultiplied into common function.

Backport of changeset 7987:beeac488af4d.

1 files changed, 6 insertions, 21 deletions

diff --git a/win32/PlatWin.cxx b/win32/PlatWin.cxx
index 3c5a5adf3..27d40fe22 100644
--- a/win32/PlatWin.cxx
+++ b/win32/PlatWin.cxx
@@ -784,15 +784,10 @@ void SurfaceGDI::DrawRGBAImage(PRectangle rc, int width, int height, const unsig
 			HBITMAP hbmOld = SelectBitmap(hMemDC, hbmMem);
 
 			for (int y=height-1; y>=0; y--) {
-				for (int x=0; x<width; x++) {
-					unsigned char *pixel = static_cast<unsigned char *>(image) + (y*width+x) * 4;
-					const unsigned char alpha = pixelsImage[3];
-					// Input is RGBA, output is BGRA with premultiplied alpha
-					pixel[2] = static_cast<unsigned char>((*pixelsImage++) * alpha / 255);
-					pixel[1] = static_cast<unsigned char>((*pixelsImage++) * alpha / 255);
-					pixel[0] = static_cast<unsigned char>((*pixelsImage++) * alpha / 255);
-					pixel[3] = *pixelsImage++;
-				}
+				// Bits flipped vertically
+				unsigned char *pixel = static_cast<unsigned char *>(image) + RGBAImage::bytesPerPixel * y * width;
+				RGBAImage::BGRAFromRGBA(pixel, pixelsImage, width);
+				pixelsImage += RGBAImage::bytesPerPixel * width;
 			}
 
 			const BLENDFUNCTION merge = { AC_SRC_OVER, 0, 255, AC_SRC_ALPHA };
@@ -1436,18 +1431,8 @@ void SurfaceD2D::DrawRGBAImage(PRectangle rc, int width, int height, const unsig
 			rc.top += std::floor((rc.Height() - height) / 2);
 		rc.bottom = rc.top + height;
 
-		std::vector<unsigned char> image(height * width * 4);
-		for (int yPixel=0; yPixel<height; yPixel++) {
-			for (int xPixel = 0; xPixel<width; xPixel++) {
-				unsigned char *pixel = &image[0] + (yPixel*width + xPixel) * 4;
-				const unsigned char alpha = pixelsImage[3];
-				// Input is RGBA, output is BGRA with premultiplied alpha
-				pixel[2] = (*pixelsImage++) * alpha / 255;
-				pixel[1] = (*pixelsImage++) * alpha / 255;
-				pixel[0] = (*pixelsImage++) * alpha / 255;
-				pixel[3] = *pixelsImage++;
-			}
-		}
+		std::vector<unsigned char> image(RGBAImage::bytesPerPixel * height * width);
+		RGBAImage::BGRAFromRGBA(image.data(), pixelsImage, static_cast<ptrdiff_t>(height) * width);
 
 		ID2D1Bitmap *bitmap = nullptr;
 		const D2D1_SIZE_U size = D2D1::SizeU(width, height);