Create fragment processor for performing input color blend with child processor

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.
  */
 
 
 
@@ skipping 59 matching lines @@
 #define GrColorUnpackB(color)   (((color) >> GrColor_SHIFT_B) & 0xFF)
 #define GrColorUnpackA(color)   (((color) >> GrColor_SHIFT_A) & 0xFF)
 
 /**
  *  Since premultiplied means that alpha >= color, we construct a color with
  *  each component==255 and alpha == 0 to be "illegal"
  */
 #define GrColor_ILLEGAL     (~(0xFF << GrColor_SHIFT_A))
 
 #define GrColor_WHITE 0xFFFFFFFF
-#define GrColor_TRANS_BLACK 0x0
+#define GrColor_TRANSPARENT_BLACK 0x0
 
 /**
  * Assert in debug builds that a GrColor is premultiplied.
  */
 static inline void GrColorIsPMAssert(GrColor SkDEBUGCODE(c)) {
 #ifdef SK_DEBUG
     unsigned a = GrColorUnpackA(c);
     unsigned r = GrColorUnpackR(c);
     unsigned g = GrColorUnpackG(c);
     unsigned b = GrColorUnpackB(c);
 
     SkASSERT(r <= a);
     SkASSERT(g <= a);
     SkASSERT(b <= a);
 #endif
 }
 
+/** Inverts each color channel. */
+static inline GrColor GrInvertColor(GrColor c) {
+    U8CPU a = GrColorUnpackA(c);
+    U8CPU r = GrColorUnpackR(c);
+    U8CPU g = GrColorUnpackG(c);
+    U8CPU b = GrColorUnpackB(c);
+    return GrColorPackRGBA(0xff - r, 0xff - g, 0xff - b, 0xff - a);
+}
+
+static inline GrColor GrColorMul(GrColor c0, GrColor c1) {
+    U8CPU r = SkMulDiv255Round(GrColorUnpackR(c0), GrColorUnpackR(c1));
+    U8CPU g = SkMulDiv255Round(GrColorUnpackG(c0), GrColorUnpackG(c1));
+    U8CPU b = SkMulDiv255Round(GrColorUnpackB(c0), GrColorUnpackB(c1));
+    U8CPU a = SkMulDiv255Round(GrColorUnpackA(c0), GrColorUnpackA(c1));
+    return GrColorPackRGBA(r, g, b, a);
+}
+
+static inline GrColor GrColorSatAdd(GrColor c0, GrColor c1) {
+    unsigned r = SkTMin<unsigned>(GrColorUnpackR(c0) + GrColorUnpackR(c1), 0xff);
+    unsigned g = SkTMin<unsigned>(GrColorUnpackG(c0) + GrColorUnpackG(c1), 0xff);
+    unsigned b = SkTMin<unsigned>(GrColorUnpackB(c0) + GrColorUnpackB(c1), 0xff);
+    unsigned a = SkTMin<unsigned>(GrColorUnpackA(c0) + GrColorUnpackA(c1), 0xff);
+    return GrColorPackRGBA(r, g, b, a);
+}
+
 /** Converts a GrColor to an rgba array of GrGLfloat */
 static inline void GrColorToRGBAFloat(GrColor color, float rgba[4]) {
     static const float ONE_OVER_255 = 1.f / 255.f;
     rgba[0] = GrColorUnpackR(color) * ONE_OVER_255;
     rgba[1] = GrColorUnpackG(color) * ONE_OVER_255;
     rgba[2] = GrColorUnpackB(color) * ONE_OVER_255;
     rgba[3] = GrColorUnpackA(color) * ONE_OVER_255;
 }
 
 /** Normalizes and coverts an uint8_t to a float. [0, 255] -> [0.0, 1.0] */
 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);
 }
 
+static inline GrColor GrPremulColor(GrColor color) {
+    unsigned r = GrColorUnpackR(color);
+    unsigned g = GrColorUnpackG(color);
+    unsigned b = GrColorUnpackB(color);
+    unsigned a = GrColorUnpackA(color);
+    return GrColorPackRGBA(SkMulDiv255Round(r, a),
+                           SkMulDiv255Round(g, a),
+                           SkMulDiv255Round(b, a),
+                           a);
+}
 /** Returns an unpremuled version of the GrColor. */
-static inline GrColor GrUnPreMulColor(GrColor color) {
+static inline GrColor GrUnpremulColor(GrColor color) {
+    GrColorIsPMAssert(color);
     unsigned r = GrColorUnpackR(color);
     unsigned g = GrColorUnpackG(color); 
     unsigned b = GrColorUnpackB(color);
     unsigned a = GrColorUnpackA(color);
     SkPMColor colorPM = SkPackARGB32(a, r, g, b);

[egdaniel, 2015/09/15 20:59:28]

maybe use your new helper GrColorToSkPMColor here?

[bsalomon, 2015/09/15 21:12:07]

now that is moved out I think the minor code duplication is better than
including all of SkGr.h in here.

     SkColor colorUPM = SkUnPreMultiply::PMColorToColor(colorPM);
 
     r = SkColorGetR(colorUPM);
     g = SkColorGetG(colorUPM);
     b = SkColorGetB(colorUPM);
     a = SkColorGetA(colorUPM);
 
     return GrColorPackRGBA(r, g, b, a);
 }
 
+static inline SkPMColor GrColorToSkPMColor(GrColor c) {
+    GrColorIsPMAssert(c);
+    return SkPackARGB32(GrColorUnpackA(c), GrColorUnpackR(c), GrColorUnpackG(c), GrColorUnpackB(c));
+}
+
+static inline GrColor SkPMColorToGrColor(SkPMColor c) {
+    return GrColorPackRGBA(SkGetPackedR32(c), SkGetPackedG32(c), SkGetPackedB32(c),
+                           SkGetPackedA32(c));
+}
+
 /**
  * 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 58 matching lines @@
     GR_STATIC_ASSERT(9  == kLATC_GrPixelConfig);
     GR_STATIC_ASSERT(10  == kR11_EAC_GrPixelConfig);
     GR_STATIC_ASSERT(11 == kASTC_12x12_GrPixelConfig);
     GR_STATIC_ASSERT(12 == kRGBA_float_GrPixelConfig);
     GR_STATIC_ASSERT(13 == kAlpha_half_GrPixelConfig);
     GR_STATIC_ASSERT(14 == kRGBA_half_GrPixelConfig);
     GR_STATIC_ASSERT(SK_ARRAY_COUNT(kFlags) == kGrPixelConfigCnt);
 }
 
 #endif