wine-staging/patches/windowscodecs-32bppGrayFloat/0004-windowscodecs-Fix-32bppGrayFloat-to-8bppGray-convers.patch

From 6d2db3592f0eccdef65691c51d16e3bb7558e8ae Mon Sep 17 00:00:00 2001
From: Dmitry Timoshkov <dmitry@baikal.ru>
Date: Mon, 7 Mar 2016 17:36:39 +0800
Subject: windowscodecs: Fix 32bppGrayFloat to 8bppGray conversion.

Intermediate conversion from 32bppGrayFloat to 24bppBGR applies sRGB gamma.
---
 dlls/windowscodecs/converter.c       | 7 ++++++-
 dlls/windowscodecs/tests/converter.c | 1 +
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/dlls/windowscodecs/converter.c b/dlls/windowscodecs/converter.c
index 322b2d1..bd5e978 100644
--- a/dlls/windowscodecs/converter.c
+++ b/dlls/windowscodecs/converter.c
@@ -1167,7 +1167,12 @@ static HRESULT copypixels_to_8bppGray(struct FormatConverter *This, const WICRec
             {
                 float gray = (bgr[2] * 0.2126f + bgr[1] * 0.7152f + bgr[0] * 0.0722f) / 255.0f;
 
-                gray = to_sRGB_component(gray) * 255.0f;
+                /* conversion from 32bppGrayFloat to 24bppBGR has already applied sRGB gamma */
+                if (source_format == format_32bppGrayFloat)
+                    gray *= 255.0f;
+                else
+                    gray = to_sRGB_component(gray) * 255.0f;
+
                 dst[x] = (BYTE)floorf(gray + 0.51f);
                 bgr += 3;
             }
diff --git a/dlls/windowscodecs/tests/converter.c b/dlls/windowscodecs/tests/converter.c
index 9dd77a5..80766ea 100644
--- a/dlls/windowscodecs/tests/converter.c
+++ b/dlls/windowscodecs/tests/converter.c
@@ -825,6 +825,7 @@ START_TEST(converter)
     test_conversion(&testdata_24bppBGR, &testdata_8bppGray, "24bppBGR -> 8bppGray", FALSE);
     test_conversion(&testdata_32bppBGR, &testdata_8bppGray, "32bppBGR -> 8bppGray", FALSE);
     test_conversion(&testdata_32bppGrayFloat, &testdata_24bppBGR_gray, "32bppGrayFloat -> 24bppBGR gray", FALSE);
+    test_conversion(&testdata_32bppGrayFloat, &testdata_8bppGray, "32bppGrayFloat -> 8bppGray", FALSE);
 
     test_invalid_conversion();
     test_default_converter();
-- 
2.7.1