Tweak distance field path renderer behavior in gamma-correct mode to match

recent changes to text rendering.

Uses linear coverage falloff. Produces results that are perceptually more
similar to L32 (raster and gpu). Smoothstep + sRGB was too soft.

Plumb the gamma-correctness via DrawPathArgs, which also paves the way for
other path rendering implementations to easily make decisions about rendering
technique based on that flag.

Fix a few typos and formatting issues from my most recent change.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1889453002

Review URL: https://codereview.chromium.org/1889453002

1 files changed, 3 insertions, 0 deletions

diff --git a/src/gpu/GrPathRenderer.h b/src/gpu/GrPathRenderer.h
index 85b3275e89..cc149061ed 100644
--- a/src/gpu/GrPathRenderer.h
+++ b/src/gpu/GrPathRenderer.h
@@ -119,6 +119,7 @@ public:
      * fPath                  the path to draw.
      * fStroke                the stroke information (width, join, cap)
      * fAntiAlias             true if anti-aliasing is required.
+     * fGammaCorrect          true if gamma-correct rendering is to be used.
      */
     struct DrawPathArgs {
         GrDrawTarget*               fTarget;
@@ -129,6 +130,7 @@ public:
         const SkPath*               fPath;
         const GrStrokeInfo*         fStroke;
         bool                        fAntiAlias;
+        bool                        fGammaCorrect;
 
         void validate() const {
             SkASSERT(fTarget);
@@ -281,6 +283,7 @@ private:
         drawArgs.fPath = args.fPath;
         drawArgs.fStroke = args.fStroke;
         drawArgs.fAntiAlias = false;
+        drawArgs.fGammaCorrect = false;
         this->drawPath(drawArgs);
     }