From 7398ed2977ec495fcd074e4c98d434b05304f19d Mon Sep 17 00:00:00 2001 From: Zhiyi Zhang Date: Wed, 25 Aug 2021 14:24:31 +0800 Subject: [PATCH] uxtheme: Use TransparentBlt() for bitmaps with all alpha values being 0xff. Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=51553 Signed-off-by: Zhiyi Zhang Signed-off-by: Alexandre Julliard (cherry picked from commit 96b7a8a317a859dd6f9bf9a0e03d303e7d3503b3) Signed-off-by: Michael Stefaniuc --- dlls/uxtheme/msstyles.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/dlls/uxtheme/msstyles.c b/dlls/uxtheme/msstyles.c index cd7677e5783..3624bb2d4a6 100644 --- a/dlls/uxtheme/msstyles.c +++ b/dlls/uxtheme/msstyles.c @@ -1074,11 +1074,18 @@ static BOOL prepare_alpha (HBITMAP bmp, BOOL* hasAlpha) if (!bmp || GetObjectW( bmp, sizeof(dib), &dib ) != sizeof(dib)) return FALSE; - if(dib.dsBm.bmBitsPixel != 32) + if (dib.dsBm.bmBitsPixel != 32 || dib.dsBmih.biCompression != BI_RGB) /* nothing to do */ return TRUE; - *hasAlpha = TRUE; + /* If all alpha values are 0xff, don't use alpha blending */ + for (n = 0, p = dib.dsBm.bmBits; n < dib.dsBmih.biWidth * dib.dsBmih.biHeight; n++, p += 4) + if ((*hasAlpha = (p[3] != 0xff))) + break; + + if (!*hasAlpha) + return TRUE; + p = dib.dsBm.bmBits; n = dib.dsBmih.biHeight * dib.dsBmih.biWidth; /* AlphaBlend() wants premultiplied alpha, so do that now */