Add function to return an unpremuled version of a GrColor

include/gpu/GrColor.h

 
 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 
 #ifndef GrColor_DEFINED
 #define GrColor_DEFINED
 
 #include "GrTypes.h"
+#include "SkColor.h"
+#include "SkColorPriv.h"
+#include "SkUnPreMultiply.h"
 
 /**
  * GrColor is 4 bytes for R, G, B, A, in a specific order defined below. The components are stored
  * premultiplied.
  */
 typedef uint32_t GrColor;
 
 // shift amount to assign a component to a GrColor int
 // These shift values are chosen for compatibility with GL attrib arrays
 // ES doesn't allow BGRA vertex attrib order so if they were not in this order
@@ skipping 67 matching lines @@
 static inline float GrNormalizeByteToFloat(uint8_t value) {
     static const float ONE_OVER_255 = 1.f / 255.f;
     return value * ONE_OVER_255;
 }
 
 /** Determines whether the color is opaque or not. */
 static inline bool GrColorIsOpaque(GrColor color) {
     return (color & (0xFFU << GrColor_SHIFT_A)) == (0xFFU << GrColor_SHIFT_A);
 }
 
+/** Returns an unpremuled version of the GrColor. */
+static inline GrColor GrUnPreMulColor(GrColor color) {
+    unsigned r = GrColorUnpackR(color);
+    unsigned g = GrColorUnpackG(color); 
+    unsigned b = GrColorUnpackB(color);
+    unsigned a = GrColorUnpackA(color);
+    SkPMColor colorPM = SkPackARGB32(a, r, g, b);
+    SkColor colorUPM = SkUnPreMultiply::PMColorToColor(colorPM);
+
+    r = SkGetPackedR32(colorUPM);
+    g = SkGetPackedG32(colorUPM);
+    b = SkGetPackedB32(colorUPM);
+    a = SkGetPackedA32(colorUPM);
+
+    return GrColorPackRGBA(r, g, b, a);
+}
+
 /**
  * Flags used for bitfields of color components. They are defined so that the bit order reflects the
  * GrColor shift order.
  */
 enum GrColorComponentFlags {
     kR_GrColorComponentFlag = 1 << (GrColor_SHIFT_R / 8),
     kG_GrColorComponentFlag = 1 << (GrColor_SHIFT_G / 8),
     kB_GrColorComponentFlag = 1 << (GrColor_SHIFT_B / 8),
     kA_GrColorComponentFlag = 1 << (GrColor_SHIFT_A / 8),
 
@@ skipping 48 matching lines @@
     GR_STATIC_ASSERT(6  == kBGRA_8888_GrPixelConfig);
     GR_STATIC_ASSERT(7  == kETC1_GrPixelConfig);
     GR_STATIC_ASSERT(8  == kLATC_GrPixelConfig);
     GR_STATIC_ASSERT(9  == kR11_EAC_GrPixelConfig);
     GR_STATIC_ASSERT(10 == kASTC_12x12_GrPixelConfig);
     GR_STATIC_ASSERT(11 == kRGBA_float_GrPixelConfig);
     GR_STATIC_ASSERT(SK_ARRAY_COUNT(kFlags) == kGrPixelConfigCnt);
 }
 
 #endif