Make "alpha only" be a property of GrTextureProducer

src/gpu/GrImageIDTextureAdjuster.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrImageIDTextureAdjuster.h"
 
 #include "GrContext.h"
 #include "GrGpuResourcePriv.h"
 #include "SkBitmap.h"
 #include "SkGrPriv.h"
 #include "SkImage_Base.h"
 #include "SkImageCacherator.h"
 #include "SkPixelRef.h"
 
+static bool bmp_is_alpha_only(const SkBitmap& bm) { return kAlpha_8_SkColorType == bm.colorType(); }
+
 GrBitmapTextureAdjuster::GrBitmapTextureAdjuster(const SkBitmap* bmp)
-    : INHERITED(bmp->getTexture(), SkIRect::MakeWH(bmp->width(), bmp->height()))
+    : INHERITED(bmp->getTexture(),
+                SkIRect::MakeWH(bmp->width(), bmp->height()),
+                bmp_is_alpha_only(*bmp))
     , fBmp(bmp) {}
 
 void GrBitmapTextureAdjuster::makeCopyKey(const CopyParams& params, GrUniqueKey* copyKey) {
     if (fBmp->isVolatile()) {
         return;
     }
     // The content area must represent the whole bitmap. Texture-backed bitmaps don't support
     // extractSubset(). Therefore, either the bitmap and the texture are the same size or the
     // content's dimensions are the bitmap's dimensions which is pinned to the upper left
     // of the texture.
     GrUniqueKey baseKey;
     GrMakeKeyFromImageID(&baseKey, fBmp->getGenerationID(),
                          SkIRect::MakeWH(fBmp->width(), fBmp->height()));
     MakeCopyKeyFromOrigKey(baseKey, params, copyKey);
 }
 
 void GrBitmapTextureAdjuster::didCacheCopy(const GrUniqueKey& copyKey) {
     GrInstallBitmapUniqueKeyInvalidator(copyKey, fBmp->pixelRef());
 }
 
 //////////////////////////////////////////////////////////////////////////////
 
+// SkImage's don't have a way of communicating whether they're alpha-only. So we fallback to
+// inspecting the texture.
+static bool tex_image_is_alpha_only(const SkImage_Base& img) {
+    return GrPixelConfigIsAlphaOnly(img.peekTexture()->config());
+}
+
 GrImageTextureAdjuster::GrImageTextureAdjuster(const SkImage_Base* img)
-    : INHERITED(img->peekTexture(), SkIRect::MakeWH(img->width(), img->height()))
+    : INHERITED(img->peekTexture(), SkIRect::MakeWH(img->width(), img->height()),
+                tex_image_is_alpha_only(*img))
     , fImageBase(img) {}
 
 void GrImageTextureAdjuster::makeCopyKey(const CopyParams& params, GrUniqueKey* copyKey) {
     // By construction this texture adjuster always represents an entire SkImage, so use the
     // image's width and height for the key's rectangle.
     GrUniqueKey baseKey;
     GrMakeKeyFromImageID(&baseKey, fImageBase->uniqueID(),
                          SkIRect::MakeWH(fImageBase->width(), fImageBase->height()));
     MakeCopyKeyFromOrigKey(baseKey, params, copyKey);
 }
 
 void GrImageTextureAdjuster::didCacheCopy(const GrUniqueKey& copyKey) {
     // We don't currently have a mechanism for notifications on Images!
 }
 
 //////////////////////////////////////////////////////////////////////////////
 
 GrBitmapTextureMaker::GrBitmapTextureMaker(GrContext* context, const SkBitmap& bitmap)
-    : INHERITED(context, bitmap.width(), bitmap.height())
+    : INHERITED(context, bitmap.width(), bitmap.height(), bmp_is_alpha_only(bitmap))
     , fBitmap(bitmap) {
     SkASSERT(!bitmap.getTexture());
     if (!bitmap.isVolatile()) {
         SkIPoint origin = bitmap.pixelRefOrigin();
         SkIRect subset = SkIRect::MakeXYWH(origin.fX, origin.fY, bitmap.width(),
                                            bitmap.height());
         GrMakeKeyFromImageID(&fOriginalKey, bitmap.pixelRef()->getGenerationID(), subset);
     }
 }
 
@@ skipping 19 matching lines @@
     if (fOriginalKey.isValid()) {
         MakeCopyKeyFromOrigKey(fOriginalKey, copyParams, copyKey);
     }
 }
 
 void GrBitmapTextureMaker::didCacheCopy(const GrUniqueKey& copyKey) {
     GrInstallBitmapUniqueKeyInvalidator(copyKey, fBitmap.pixelRef());
 }
 
 //////////////////////////////////////////////////////////////////////////////
-
+static bool cacher_is_alpha_only(const SkImageCacherator& cacher) {
+    return kAlpha_8_SkColorType == cacher.info().colorType();
+}
 GrImageTextureMaker::GrImageTextureMaker(GrContext* context, SkImageCacherator* cacher,
                                          const SkImage* client, SkImage::CachingHint chint)
-    : INHERITED(context, cacher->info().width(), cacher->info().height())
+    : INHERITED(context, cacher->info().width(), cacher->info().height(),
+                cacher_is_alpha_only(*cacher))
     , fCacher(cacher)
     , fClient(client)
     , fCachingHint(chint) {
     if (client) {
         GrMakeKeyFromImageID(&fOriginalKey, client->uniqueID(),
                              SkIRect::MakeWH(this->width(), this->height()));
     }
 }
 
 GrTexture* GrImageTextureMaker::refOriginalTexture() {
     return fCacher->lockTexture(this->context(), fOriginalKey, fClient, fCachingHint);
 }
 
 void GrImageTextureMaker::makeCopyKey(const CopyParams& stretch, GrUniqueKey* paramsCopyKey) {
     if (fOriginalKey.isValid() && SkImage::kAllow_CachingHint == fCachingHint) {
         MakeCopyKeyFromOrigKey(fOriginalKey, stretch, paramsCopyKey);
     }
 }
 
 void GrImageTextureMaker::didCacheCopy(const GrUniqueKey& copyKey) {
     if (fClient) {
         as_IB(fClient)->notifyAddedToCache();
     }
 }