Exact Ganesh Gradients for Special Cases

src/effects/gradients/SkSweepGradient.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkSweepGradient.h"
 
 static SkMatrix translate(SkScalar dx, SkScalar dy) {
@@ skipping 200 matching lines @@
 
 void GrSweepGradient::GLSLSweepProcessor::emitCode(EmitArgs& args) {
     const GrSweepGradient& ge = args.fFp.cast<GrSweepGradient>();
     this->emitUniforms(args.fUniformHandler, ge);
     SkString coords2D = args.fFragBuilder->ensureFSCoords2D(args.fCoords, 0);
     SkString t;
     // 0.1591549430918 is 1/(2*pi), used since atan returns values [-pi, pi]
     // On Intel GPU there is an issue where it reads the second arguement to atan "- %s.x" as an int
     // thus must us -1.0 * %s.x to work correctly
     if (args.fGLSLCaps->mustForceNegatedAtanParamToFloat()){
-        t.printf("atan(- %s.y, -1.0 * %s.x) * 0.1591549430918 + 0.5",
+        t.printf("(atan(- %s.y, -1.0 * %s.x) * 0.1591549430918 + 0.5)",
                  coords2D.c_str(), coords2D.c_str());
     } else {
-        t.printf("atan(- %s.y, - %s.x) * 0.1591549430918 + 0.5",
+        t.printf("(atan(- %s.y, - %s.x) * 0.1591549430918 + 0.5)",
                  coords2D.c_str(), coords2D.c_str());
     }
     this->emitColor(args.fFragBuilder,
                     args.fUniformHandler,
                     args.fGLSLCaps,
                     ge, t.c_str(),
                     args.fOutputColor,
                     args.fInputColor,
                     args.fTexSamplers);
 }
@@ skipping 29 matching lines @@
     str->appendScalar(fCenter.fX);
     str->append(", ");
     str->appendScalar(fCenter.fY);
     str->append(") ");
 
     this->INHERITED::toString(str);
 
     str->append(")");
 }
 #endif