Improve drawing scaled image with raster using SSE2

That codepath is taken in qml when an Image specify with and hight and
is not smooth, and the image contains alpha contents

The changes in qdrawingprimitive_sse2_p.h just put some code from the
BLEND_SOURCE_OVER_ARGB32_SSE2 macro into a sub macro to allow its reuse

The code that is not SSE2 in qt_scale_image_argb32_on_argb32_sse2 comes
from the qt_scale_image_argb32_on_argb32 in qblendfunctions.cpp

Change-Id: I071a040af4514fb21777dead9f7c5baf16071d59
Reviewed-by: Samuel Rødal <samuel.rodal@nokia.com>

1 files changed, 28 insertions, 22 deletions

diff --git a/src/gui/painting/qdrawingprimitive_sse2_p.h b/src/gui/painting/qdrawingprimitive_sse2_p.h
index 4c66d90bf1..dad8f6cb5d 100644
--- a/src/gui/painting/qdrawingprimitive_sse2_p.h
+++ b/src/gui/painting/qdrawingprimitive_sse2_p.h
@@ -128,6 +128,33 @@ QT_BEGIN_NAMESPACE
     result = _mm_or_si128(finalAG, finalRB); \
 }
 
+// same as BLEND_SOURCE_OVER_ARGB32_SSE2, but for one vector srcVector
+#define BLEND_SOURCE_OVER_ARGB32_SSE2_helper(dst, srcVector, nullVector, half, one, colorMask, alphaMask) { \
+        const __m128i srcVectorAlpha = _mm_and_si128(srcVector, alphaMask); \
+        if (_mm_movemask_epi8(_mm_cmpeq_epi32(srcVectorAlpha, alphaMask)) == 0xffff) { \
+            /* all opaque */ \
+            _mm_store_si128((__m128i *)&dst[x], srcVector); \
+        } else if (_mm_movemask_epi8(_mm_cmpeq_epi32(srcVectorAlpha, nullVector)) != 0xffff) { \
+            /* not fully transparent */ \
+            /* extract the alpha channel on 2 x 16 bits */ \
+            /* so we have room for the multiplication */ \
+            /* each 32 bits will be in the form 0x00AA00AA */ \
+            /* with A being the 1 - alpha */ \
+            __m128i alphaChannel = _mm_srli_epi32(srcVector, 24); \
+            alphaChannel = _mm_or_si128(alphaChannel, _mm_slli_epi32(alphaChannel, 16)); \
+            alphaChannel = _mm_sub_epi16(one, alphaChannel); \
+ \
+            const __m128i dstVector = _mm_load_si128((__m128i *)&dst[x]); \
+            __m128i destMultipliedByOneMinusAlpha; \
+            BYTE_MUL_SSE2(destMultipliedByOneMinusAlpha, dstVector, alphaChannel, colorMask, half); \
+ \
+            /* result = s + d * (1-alpha) */\
+            const __m128i result = _mm_add_epi8(srcVector, destMultipliedByOneMinusAlpha); \
+            _mm_store_si128((__m128i *)&dst[x], result); \
+        } \
+    }
+
+
 // Basically blend src over dst with the const alpha defined as constAlphaVector.
 // nullVector, half, one, colorMask are constant across the whole image/texture, and should be defined as:
 //const __m128i nullVector = _mm_set1_epi32(0);
@@ -153,28 +180,7 @@ QT_BEGIN_NAMESPACE
 \
     for (; x < length-3; x += 4) { \
         const __m128i srcVector = _mm_loadu_si128((__m128i *)&src[x]); \
-        const __m128i srcVectorAlpha = _mm_and_si128(srcVector, alphaMask); \
-        if (_mm_movemask_epi8(_mm_cmpeq_epi32(srcVectorAlpha, alphaMask)) == 0xffff) { \
-            /* all opaque */ \
-            _mm_store_si128((__m128i *)&dst[x], srcVector); \
-        } else if (_mm_movemask_epi8(_mm_cmpeq_epi32(srcVectorAlpha, nullVector)) != 0xffff) { \
-            /* not fully transparent */ \
-            /* extract the alpha channel on 2 x 16 bits */ \
-            /* so we have room for the multiplication */ \
-            /* each 32 bits will be in the form 0x00AA00AA */ \
-            /* with A being the 1 - alpha */ \
-            __m128i alphaChannel = _mm_srli_epi32(srcVector, 24); \
-            alphaChannel = _mm_or_si128(alphaChannel, _mm_slli_epi32(alphaChannel, 16)); \
-            alphaChannel = _mm_sub_epi16(one, alphaChannel); \
- \
-            const __m128i dstVector = _mm_load_si128((__m128i *)&dst[x]); \
-            __m128i destMultipliedByOneMinusAlpha; \
-            BYTE_MUL_SSE2(destMultipliedByOneMinusAlpha, dstVector, alphaChannel, colorMask, half); \
- \
-            /* result = s + d * (1-alpha) */\
-            const __m128i result = _mm_add_epi8(srcVector, destMultipliedByOneMinusAlpha); \
-            _mm_store_si128((__m128i *)&dst[x], result); \
-        } \
+        BLEND_SOURCE_OVER_ARGB32_SSE2_helper(dst, srcVector, nullVector, half, one, colorMask, alphaMask) \
     } \
     for (; x < length; ++x) { \
         uint s = src[x]; \