Use threshold of 1 texture coord value per pixel w/ nearest neighbor.

src/core/SkXfermode.cpp

 
 /*
  * 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.
  */
 
 #include "SkXfermode.h"
 #include "SkXfermode_opts_SSE2.h"
@@ skipping 1208 matching lines @@
         typedef GrGLFragmentProcessor INHERITED;
     };
 
     GR_DECLARE_FRAGMENT_PROCESSOR_TEST;
 
 private:
     XferEffect(SkXfermode::Mode mode, GrTexture* background)
         : fMode(mode) {
         this->initClassID<XferEffect>();
         if (background) {
-            fBackgroundTransform.reset(kLocal_GrCoordSet, background);
+            fBackgroundTransform.reset(kLocal_GrCoordSet, background, 
+                                       GrTextureParams::kNone_FilterMode);
             this->addCoordTransform(&fBackgroundTransform);
             fBackgroundAccess.reset(background);
             this->addTextureAccess(&fBackgroundAccess);
         } else {
             this->setWillReadDstColor();
         }
     }
     virtual bool onIsEqual(const GrFragmentProcessor& other) const SK_OVERRIDE {
         const XferEffect& s = other.cast<XferEffect>();
         return fMode == s.fMode;
@@ skipping 712 matching lines @@
         } else {
             proc16 = rec.fProc16_General;
         }
     }
     return proc16;
 }
 
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_START(SkXfermode)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkProcCoeffXfermode)
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_END