funnel all constant colors through append_constant_color()

My next step is to change the uniform_color context to

    struct {
       float r,g,b,a;
       uint32_t rgba;
    };

so that it's trivial to load in both float and 8-bit pipelines.

Change-Id: If9bdde353ced3bf9eb0c63204b4770ed614ad16b
Reviewed-on: https://skia-review.googlesource.com/30481
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Mike Klein <mtklein@chromium.org>

bench/SkRasterPipelineBench.cpp

@@ -123,8 +123,9 @@ public:
 
         SkColorSpaceTransferFn from_2dot2 = gamma(  2.2f),
                                  to_2dot2 = gamma(1/2.2f);
-        SkRasterPipeline_<256> p;
-        p.append(SkRasterPipeline::uniform_color, &c);
+        SkSTArenaAlloc<256> alloc;
+        SkRasterPipeline p(&alloc);
+        p.append_constant_color(&alloc, c);
         p.append(SkRasterPipeline::parametric_r, &from_2dot2);
         p.append(SkRasterPipeline::parametric_g, &from_2dot2);
         p.append(SkRasterPipeline::parametric_b, &from_2dot2);

src/core/SkPM4fPriv.h

@@ -167,8 +167,9 @@ static inline SkColor4f to_colorspace(const SkColor4f& c, SkColorSpace* src, SkC
 
         float scratch_matrix_3x4[12];
 
-        SkRasterPipeline_<256> p;
-        p.append(SkRasterPipeline::uniform_color, &color4f);
+        SkSTArenaAlloc<256> alloc;
+        SkRasterPipeline p(&alloc);
+        p.append_constant_color(&alloc, color4f);
         append_gamut_transform(&p, scratch_matrix_3x4, src, dst, kUnpremul_SkAlphaType);
         p.append(SkRasterPipeline::store_f32, &color4f_ptr);
 

src/core/SkRasterPipeline.cpp

@@ -19,7 +19,8 @@ void SkRasterPipeline::reset() {
 }
 
 void SkRasterPipeline::append(StockStage stage, void* ctx) {
-    SkASSERT(stage != from_srgb);
+    SkASSERT(stage != from_srgb);      // Please use append_from_srgb().
+    SkASSERT(stage != uniform_color);  // Please use append_constant_color().
     this->unchecked_append(stage, ctx);
 }
 void SkRasterPipeline::unchecked_append(StockStage stage, void* ctx) {
@@ -78,17 +79,17 @@ void SkRasterPipeline::dump() const {
     #define INC_COLOR
 #endif
 
-void SkRasterPipeline::append_constant_color(SkArenaAlloc* alloc, const SkPM4f& c) {
-    if (c.r() == 0 && c.g() == 0 && c.b() == 0 && c.a() == 1) {
+void SkRasterPipeline::append_constant_color(SkArenaAlloc* alloc, const float rgba[4]) {
+    if (rgba[0] == 0 && rgba[1] == 0 && rgba[2] == 0 && rgba[3] == 1) {
         this->append(black_color);
         INC_BLACK;
-    } else if (c.r() == 1 && c.g() == 1 && c.b() == 1 && c.a() == 1) {
+    } else if (rgba[0] == 1 && rgba[1] == 1 && rgba[2] == 1 && rgba[3] == 1) {
         this->append(white_color);
         INC_WHITE;
     } else {
         float* storage = alloc->makeArray<float>(4);
-        memcpy(storage, c.fVec, 4 * sizeof(float));
-        this->append(uniform_color, storage);
+        memcpy(storage, rgba, 4 * sizeof(float));
+        this->unchecked_append(uniform_color, storage);
         INC_COLOR;
     }
 

src/core/SkRasterPipeline.h

@@ -11,6 +11,7 @@
 #include "SkArenaAlloc.h"
 #include "SkImageInfo.h"
 #include "SkNx.h"
+#include "SkPM4f.h"
 #include "SkTArray.h"
 #include "SkTypes.h"
 #include <functional>
@@ -18,7 +19,6 @@
 
 struct SkJumper_constants;
 struct SkJumper_Engine;
-struct SkPM4f;
 
 /**
  * SkRasterPipeline provides a cheap way to chain together a pixel processing pipeline.
@@ -135,7 +135,14 @@ public:
 
     // Appends a stage for a constant uniform color.
     // Tries to optimize the stage based on the color.
-    void append_constant_color(SkArenaAlloc*, const SkPM4f& color);
+    void append_constant_color(SkArenaAlloc*, const float rgba[4]);
+
+    void append_constant_color(SkArenaAlloc* alloc, const SkPM4f& color) {
+        this->append_constant_color(alloc, color.fVec);
+    }
+    void append_constant_color(SkArenaAlloc* alloc, const SkColor4f& color) {
+        this->append_constant_color(alloc, color.vec());
+    }
 
     bool empty() const { return fStages == nullptr; }
 

tests/SRGBTest.cpp

@@ -71,8 +71,9 @@ DEF_TEST(sk_pipeline_srgb_edge_cases, r) {
 
     SkJumper_MemoryCtx dst = { &color, 0 };
 
-    SkRasterPipeline_<256> p;
-    p.append(SkRasterPipeline::uniform_color, &color);
+    SkSTArenaAlloc<256> alloc;
+    SkRasterPipeline p(&alloc);
+    p.append_constant_color(&alloc, color);
     p.append(SkRasterPipeline::to_srgb);
     p.append(SkRasterPipeline::store_f32, &dst);
     p.run(0,0,4,1);

tests/SkRasterPipelineTest.cpp

@@ -282,8 +282,9 @@ DEF_TEST(SkRasterPipeline_repeat_tiling, r) {
     float out[4 * SkJumper_kMaxStride];
     SkJumper_TileCtx tile = { 9.0f, 1/9.0f };
 
-    SkRasterPipeline_<256> p;
-    p.append(SkRasterPipeline::uniform_color, in);
+    SkSTArenaAlloc<256> alloc;
+    SkRasterPipeline p(&alloc);
+    p.append_constant_color(&alloc, in);
     p.append(SkRasterPipeline::repeat_x, &tile);
     p.append(SkRasterPipeline::store_rgba, out);
     p.run(0,0,1,1);