commit 267e00addb5e7d0a8ae837a71232619560e32058
author Carl Woffenden <cwoffenden@gmail.com> Sat Oct 05 11:47:46 2019 +0200
committer Carl Woffenden <cwoffenden@gmail.com> Sat Oct 05 11:47:46 2019 +0200
tree 9c67fc08aa7f349ce1c5a38d4901d768acd19516
parent a88ff8b9ac5ef4548a1f994ce4d433478cf2a320

Minor performance tweak to the DIB creation loop

contrib/previewers/win/helpers.cpp

diff --git a/contrib/previewers/win/helpers.cpp b/contrib/previewers/win/helpers.cpp
index 937601c..d4236de 100644
--- a/contrib/previewers/win/helpers.cpp
+++ b/contrib/previewers/win/helpers.cpp
@@ -41,13 +41,11 @@
 	 */
 	if (hbmp && pixels) {
 		uint32_t* dst = static_cast<uint32_t*>(pixels);
-		for (unsigned y = 0; y < imgH; y++) {
-			for (unsigned x = 0; x < imgW; x++) {
-				uint32_t rgba = *src++;
-				*dst++ = ((rgba & 0x000000FF) << 16)
-					   | ((rgba & 0xFF00FF00)      )
-					   | ((rgba & 0x00FF0000) >> 16);
-			}
+		for (unsigned xy = imgW * imgH; xy > 0; xy--) {
+			uint32_t rgba = *src++;
+			*dst++ = ((rgba & 0x000000FF) << 16)
+				   | ((rgba & 0xFF00FF00)      )
+				   | ((rgba & 0x00FF0000) >> 16);
 		}
 		GdiFlush();
 	}