Move SkGammaColorFilter to tools, limit to sRGB

Similarly, limit GrGammaEffect to sRGB (and rename it).

BUG=skia:

Change-Id: I88feef11ab7040bca2fa4c2eed71923ded87a0d0
Reviewed-on: https://skia-review.googlesource.com/7375
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>

3 files changed, 51 insertions, 2 deletions

diff --git a/tools/sk_tool_utils.cpp b/tools/sk_tool_utils.cpp
index 93f5b107f2..0383897bd8 100644
--- a/tools/sk_tool_utils.cpp
+++ b/tools/sk_tool_utils.cpp
@@ -22,6 +22,38 @@
 
 DEFINE_bool(portableFonts, false, "Use portable fonts");
 
+#if SK_SUPPORT_GPU
+#include "effects/GrSRGBEffect.h"
+#include "SkColorFilter.h"
+
+// Color filter that just wraps GrSRGBEffect
+class SkSRGBColorFilter : public SkColorFilter {
+public:
+    static sk_sp<SkColorFilter> Make(GrSRGBEffect::Mode mode) {
+        return sk_sp<SkColorFilter>(new SkSRGBColorFilter(mode));
+    }
+
+    sk_sp<GrFragmentProcessor> asFragmentProcessor(GrContext*, SkColorSpace*) const override {
+        return GrSRGBEffect::Make(fMode);
+    }
+
+    void filterSpan(const SkPMColor src[], int count, SkPMColor dst[]) const override {
+        SK_ABORT("SkSRGBColorFilter is only implemented for GPU");
+    }
+    Factory getFactory() const override { return nullptr; }
+
+#ifndef SK_IGNORE_TO_STRING
+    void toString(SkString* str) const override {}
+#endif
+
+private:
+    SkSRGBColorFilter(GrSRGBEffect::Mode mode) : fMode(mode) {}
+
+    GrSRGBEffect::Mode fMode;
+    typedef SkColorFilter INHERITED;
+};
+#endif
+
 namespace sk_tool_utils {
 
 /* these are the default fonts chosen by Chrome for serif, sans-serif, and monospace */
@@ -586,4 +618,14 @@ void copy_to_g8(SkBitmap* dst, const SkBitmap& src) {
     }
 }
 
+#if SK_SUPPORT_GPU
+sk_sp<SkColorFilter> MakeLinearToSRGBColorFilter() {
+    return SkSRGBColorFilter::Make(GrSRGBEffect::Mode::kLinearToSRGB);
+}
+
+sk_sp<SkColorFilter> MakeSRGBToLinearColorFilter() {
+    return SkSRGBColorFilter::Make(GrSRGBEffect::Mode::kSRGBToLinear);
+}
+#endif
+
 }  // namespace sk_tool_utils
diff --git a/tools/sk_tool_utils.h b/tools/sk_tool_utils.h
index ffe8084f7f..e319411349 100644
--- a/tools/sk_tool_utils.h
+++ b/tools/sk_tool_utils.h
@@ -19,6 +19,7 @@
 
 class SkBitmap;
 class SkCanvas;
+class SkColorFilter;
 class SkPaint;
 class SkPath;
 class SkRRect;
@@ -254,6 +255,11 @@ namespace sk_tool_utils {
 
     void copy_to_g8(SkBitmap* dst, const SkBitmap& src);
 
+#if SK_SUPPORT_GPU
+    sk_sp<SkColorFilter> MakeLinearToSRGBColorFilter();
+    sk_sp<SkColorFilter> MakeSRGBToLinearColorFilter();
+#endif
+
 }  // namespace sk_tool_utils
 
 #endif  // sk_tool_utils_DEFINED
diff --git a/tools/viewer/sk_app/mac/RasterWindowContext_mac.cpp b/tools/viewer/sk_app/mac/RasterWindowContext_mac.cpp
index fd2f2effb1..4749bc79a2 100644
--- a/tools/viewer/sk_app/mac/RasterWindowContext_mac.cpp
+++ b/tools/viewer/sk_app/mac/RasterWindowContext_mac.cpp
@@ -8,7 +8,8 @@
 
 #include "../GLWindowContext.h"
 #include "SkCanvas.h"
-#include "SkGammaColorFilter.h"
+#include "SkColorFilter.h"
+#include "sk_tool_utils.h"
 #include "WindowContextFactory_mac.h"
 
 #include "SDL.h"
@@ -123,7 +124,7 @@ void RasterWindowContext_mac::onSwapBuffers() {
         SkPaint gammaPaint;
         gammaPaint.setBlendMode(SkBlendMode::kSrc);
         if (doGamma) {
-            gammaPaint.setColorFilter(SkGammaColorFilter::Make(1.0f / 2.2f));
+            gammaPaint.setColorFilter(sk_tool_utils::MakeLinearToSRGBColorFilter());
         }
 
         sk_sp<SkSurface> gpuSurface = INHERITED::getBackbufferSurface();