Add output format properties to SkImageFilter::Context

src/core/SkBlurImageFilter.cpp

 /*
  * Copyright 2011 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 "SkAutoPixmapStorage.h"
 #include "SkColorPriv.h"
 #include "SkGpuBlurUtils.h"
@@ skipping 139 matching lines @@
             offset->fX = inputBounds.x();
             offset->fY = inputBounds.y();
             return input->makeSubset(inputBounds.makeOffset(-inputOffset.x(),
                                                             -inputOffset.y()));
         }
 
         offset->fX = dstBounds.fLeft;
         offset->fY = dstBounds.fTop;
         inputBounds.offset(-inputOffset);
         dstBounds.offset(-inputOffset);
+        // We intentionally use the source's color space, not the destination's (from ctx). We
+        // always blur in the source's config, so we need a compatible color space. We also want to
+        // avoid doing gamut conversion on every fetch of the texture.
         sk_sp<GrDrawContext> drawContext(SkGpuBlurUtils::GaussianBlur(
                                                                 context,
                                                                 inputTexture.get(),
                                                                 sk_ref_sp(source->getColorSpace()),
                                                                 dstBounds,
                                                                 &inputBounds,
                                                                 sigma.x(),
                                                                 sigma.y()));
         if (!drawContext) {
             return nullptr;
@@ skipping 117 matching lines @@
     str->appendf("SkBlurImageFilterImpl: (");
     str->appendf("sigma: (%f, %f) input (", fSigma.fWidth, fSigma.fHeight);
 
     if (this->getInput(0)) {
         this->getInput(0)->toString(str);
     }
 
     str->append("))");
 }
 #endif