starter procs for blending with pm4f

include/core/SkColor.h

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkColor_DEFINED
 #define SkColor_DEFINED
 
@@ skipping 92 matching lines @@
 */
 SK_API void SkRGBToHSV(U8CPU red, U8CPU green, U8CPU blue, SkScalar hsv[3]);
 
 /** Convert the argb color to its HSV components.
         hsv[0] is Hue [0 .. 360)
         hsv[1] is Saturation [0...1]
         hsv[2] is Value [0...1]
     @param color the argb color to convert. Note: the alpha component is ignored.
     @param hsv  3 element array which holds the resulting HSV components.
 */
-static inline void SkColorToHSV(SkColor color, SkScalar hsv[3])
-{
+static inline void SkColorToHSV(SkColor color, SkScalar hsv[3]) {
     SkRGBToHSV(SkColorGetR(color), SkColorGetG(color), SkColorGetB(color), hsv);
 }
 
 /** Convert HSV components to an ARGB color. The alpha component is passed through unchanged.
         hsv[0] is Hue [0 .. 360)
         hsv[1] is Saturation [0...1]
         hsv[2] is Value [0...1]
     If hsv values are out of range, they are pinned.
     @param alpha the alpha component of the returned argb color.
     @param hsv  3 element array which holds the input HSV components.
     @return the resulting argb color
 */
 SK_API SkColor SkHSVToColor(U8CPU alpha, const SkScalar hsv[3]);
 
 /** Convert HSV components to an ARGB color. The alpha component set to 0xFF.
         hsv[0] is Hue [0 .. 360)
         hsv[1] is Saturation [0...1]
         hsv[2] is Value [0...1]
     If hsv values are out of range, they are pinned.
     @param hsv  3 element array which holds the input HSV components.
     @return the resulting argb color
 */
-static inline SkColor SkHSVToColor(const SkScalar hsv[3])
-{
+static inline SkColor SkHSVToColor(const SkScalar hsv[3]) {
     return SkHSVToColor(0xFF, hsv);
 }
 
 ////////////////////////////////////////////////////////////////////////
 
 /** 32 bit ARGB color value, premultiplied. The byte order for this value is
     configuration dependent, matching the format of kARGB32 bitmaps. This is different
     from SkColor, which is nonpremultiplied, and is always in the same byte order.
 */
 typedef uint32_t SkPMColor;
@@ skipping 10 matching lines @@
 /** Define a function pointer type for combining two premultiplied colors
 */
 typedef SkPMColor (*SkXfermodeProc)(SkPMColor src, SkPMColor dst);
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 
 /*
  *  The float values are 0...1 premultiplied
  */
 struct SkPM4f {
+    enum {
+        A = SK_A32_SHIFT/8,
+        R = SK_R32_SHIFT/8,
+        G = SK_G32_SHIFT/8,
+        B = SK_B32_SHIFT/8,
+    };

[mtklein, 2016/01/29 15:23:00]

+1

     float fVec[4];
 
-    float a() const { return fVec[SK_A32_SHIFT/8]; }
+    float a() const { return fVec[3]; }

[mtklein, 2016/01/29 15:23:00]

Ahem, fVec[A];

[reed1, 2016/01/29 22:35:27]

Doh

 
     static SkPM4f FromPMColor(SkPMColor);
+
+    bool isUnit() const;
 };
 
 /*
  *  The float values are 0...1 unpremultiplied
  */
 struct SkColor4f {
     float fA;
     float fR;
     float fG;
     float fB;
@@ skipping 12 matching lines @@
     static SkColor4f FromColor(SkColor);
 
     SkColor4f pin() const {
         return Pin(fA, fR, fG, fB);
     }
 
     SkPM4f premul() const;
 };
 
 #endif