add SkBitmap::installPixelRef()

BUG=
R=scroggo@google.com

Review URL: https://codereview.chromium.org/129423002

git-svn-id: http://skia.googlecode.com/svn/trunk@13055 2bbb7eff-a529-9590-31e7-b0007b416f81

15 files changed, 114 insertions, 46 deletions

diff --git a/include/core/SkBitmap.h b/include/core/SkBitmap.h
index b8117bd76f..1cb4fd7f35 100644
--- a/include/core/SkBitmap.h
+++ b/include/core/SkBitmap.h
@@ -268,6 +268,16 @@ public:
     */
     void setPixels(void* p, SkColorTable* ctable = NULL);
 
+    /**
+     *  Install the specified pixelref into the bitmap, with an optional rect
+     *  for referencing a subset of the pixels in the pixelref. This sets the
+     *  config/width/height/alphatype of the bitmap to match the pixelref.
+     *
+     *  The subset rect, if not null, is intersected with the bounds of the
+     *  pixelref (taken from its SkImageInfo).
+     */
+    SkPixelRef* installPixelRef(SkPixelRef*, const SkIRect* subset = NULL);
+
     /** Copies the bitmap's pixels to the location pointed at by dst and returns
         true if possible, returns false otherwise.
 
diff --git a/include/core/SkImageInfo.h b/include/core/SkImageInfo.h
index 1165479f74..e0bce2a7c0 100644
--- a/include/core/SkImageInfo.h
+++ b/include/core/SkImageInfo.h
@@ -109,6 +109,60 @@ struct SkImageInfo {
     SkColorType fColorType;
     SkAlphaType fAlphaType;
 
+    static SkImageInfo Make(int width, int height, SkColorType ct, SkAlphaType at) {
+        SkASSERT(width >= 0);
+        SkASSERT(height >= 0);
+        SkImageInfo info = {
+            width, height, ct, at
+        };
+        return info;
+    }
+
+    /**
+     *  Sets colortype to the native ARGB32 type.
+     */
+    static SkImageInfo MakeN32(int width, int height, SkAlphaType at) {
+        SkASSERT(width >= 0);
+        SkASSERT(height >= 0);
+        SkImageInfo info = {
+            width, height, kPMColor_SkColorType, at
+        };
+        return info;
+    }
+
+    /**
+     *  Sets colortype to the native ARGB32 type, and the alphatype to premul.
+     */
+    static SkImageInfo MakeN32Premul(int width, int height) {
+        SkASSERT(width >= 0);
+        SkASSERT(height >= 0);
+        SkImageInfo info = {
+            width, height, kPMColor_SkColorType, kPremul_SkAlphaType
+        };
+        return info;
+    }
+
+    /**
+     *  Sets colortype to the native ARGB32 type, and the alphatype to opaque.
+     */
+    static SkImageInfo MakeN32Opaque(int width, int height) {
+        SkASSERT(width >= 0);
+        SkASSERT(height >= 0);
+        SkImageInfo info = {
+            width, height, kPMColor_SkColorType, kOpaque_SkAlphaType
+        };
+        return info;
+    }
+    
+    static SkImageInfo MakeA8(int width, int height) {
+        SkASSERT(width >= 0);
+        SkASSERT(height >= 0);
+        SkImageInfo info = {
+            width, height, kAlpha_8_SkColorType, kPremul_SkAlphaType
+        };
+        return info;
+    }
+    
     bool isOpaque() const {
         return SkAlphaTypeIsOpaque(fAlphaType);
     }
diff --git a/src/core/SkBitmap.cpp b/src/core/SkBitmap.cpp
index f950e28cdc..6615b1c52b 100644
--- a/src/core/SkBitmap.cpp
+++ b/src/core/SkBitmap.cpp
@@ -333,6 +333,30 @@ bool SkBitmap::setAlphaType(SkAlphaType alphaType) {
     return true;
 }
 
+SkPixelRef* SkBitmap::installPixelRef(SkPixelRef* pr, const SkIRect* subset) {
+    if (NULL == pr) {
+        this->reset();
+        return NULL;
+    }
+
+    const SkImageInfo& info = pr->info();
+
+    fConfig = SkColorTypeToBitmapConfig(info.fColorType);
+    fAlphaType = info.fAlphaType;
+    fBytesPerPixel = info.bytesPerPixel();
+    // not known until we're locked
+    fRowBytes = 0;
+    
+    SkIRect bounds = { 0, 0, info.fWidth, info.fHeight };
+    if (subset && !bounds.intersect(*subset)) {
+        bounds.setEmpty();
+    }
+
+    fWidth = bounds.width();
+    fHeight = bounds.height();
+    return this->setPixelRef(pr, bounds.left(), bounds.top());
+}
+
 void SkBitmap::updatePixelsFromRef() const {
     if (NULL != fPixelRef) {
         if (fPixelLockCount > 0) {
diff --git a/src/core/SkImageFilterUtils.cpp b/src/core/SkImageFilterUtils.cpp
index 92fe67e84c..076ef9bb91 100644
--- a/src/core/SkImageFilterUtils.cpp
+++ b/src/core/SkImageFilterUtils.cpp
@@ -15,14 +15,8 @@
 #include "SkGr.h"
 
 bool SkImageFilterUtils::WrapTexture(GrTexture* texture, int width, int height, SkBitmap* result) {
-    SkImageInfo info = {
-        width,
-        height,
-        kPMColor_SkColorType,
-        kPremul_SkAlphaType,
-    };
-    result->setConfig(info);
-    result->setPixelRef(SkNEW_ARGS(SkGrPixelRef, (info, texture)))->unref();
+    SkImageInfo info = SkImageInfo::MakeN32Premul(width, height);
+    result->installPixelRef(SkNEW_ARGS(SkGrPixelRef, (info, texture)))->unref();
     return true;
 }
 
diff --git a/src/core/SkScaledImageCache.cpp b/src/core/SkScaledImageCache.cpp
index fc3148bdd8..68663f03b0 100644
--- a/src/core/SkScaledImageCache.cpp
+++ b/src/core/SkScaledImageCache.cpp
@@ -293,14 +293,10 @@ bool SkScaledImageCacheDiscardableAllocator::allocPixelRef(SkBitmap* bitmap,
         return false;
     }
 
-    SkImageInfo info = {
-        bitmap->width(),
-        bitmap->height(),
-        kPMColor_SkColorType,
-        bitmap->alphaType()
-    };
-
-    bitmap->setPixelRef(SkNEW_ARGS(SkOneShotDiscardablePixelRef,
+    SkImageInfo info = SkImageInfo::MakeN32(bitmap->width(), bitmap->height(),
+                                            bitmap->alphaType());
+
+    bitmap->installPixelRef(SkNEW_ARGS(SkOneShotDiscardablePixelRef,
                                    (info, dm, bitmap->rowBytes())))->unref();
     bitmap->lockPixels();
     return bitmap->readyToDraw();
diff --git a/src/effects/gradients/SkGradientShader.cpp b/src/effects/gradients/SkGradientShader.cpp
index 6925ad2e4b..8ed40a7dda 100644
--- a/src/effects/gradients/SkGradientShader.cpp
+++ b/src/effects/gradients/SkGradientShader.cpp
@@ -583,8 +583,7 @@ void SkGradientShaderBase::getGradientTableBitmap(SkBitmap* bitmap) const {
     if (fMapper) {
         // force our cahce32pixelref to be built
         (void)this->getCache32();
-        bitmap->setConfig(SkBitmap::kARGB_8888_Config, kCache32Count, 1);
-        bitmap->setPixelRef(fCache32PixelRef);
+        bitmap->installPixelRef(fCache32PixelRef);
         return;
     }
 
@@ -624,8 +623,7 @@ void SkGradientShaderBase::getGradientTableBitmap(SkBitmap* bitmap) const {
     if (!gCache->find(storage.get(), size, bitmap)) {
         // force our cahce32pixelref to be built
         (void)this->getCache32();
-        bitmap->setConfig(SkBitmap::kARGB_8888_Config, kCache32Count, 1);
-        bitmap->setPixelRef(fCache32PixelRef);
+        bitmap->installPixelRef(fCache32PixelRef);
 
         gCache->add(storage.get(), size, *bitmap);
     }
diff --git a/src/image/SkImagePriv.cpp b/src/image/SkImagePriv.cpp
index 43cc44b2fa..af15a7599b 100644
--- a/src/image/SkImagePriv.cpp
+++ b/src/image/SkImagePriv.cpp
@@ -74,7 +74,7 @@ SkImage* SkNewImageFromBitmap(const SkBitmap& bm, bool canSharePixelRef) {
 
     SkImage* image = NULL;
     if (canSharePixelRef || bm.isImmutable()) {
-        image = SkNewImageFromPixelRef(info, bm.pixelRef(), bm.rowBytes());
+        image = SkNewImageFromPixelRef(bm.pixelRef());
     } else {
         bm.lockPixels();
         if (bm.getPixels()) {
diff --git a/src/image/SkImagePriv.h b/src/image/SkImagePriv.h
index 7c19c734c2..2812a8f72d 100644
--- a/src/image/SkImagePriv.h
+++ b/src/image/SkImagePriv.h
@@ -18,8 +18,7 @@ extern SkBitmap::Config SkColorTypeToBitmapConfig(SkColorType);
 extern bool SkBitmapConfigToColorType(SkBitmap::Config, SkColorType* ctOut);
 
 // Call this if you explicitly want to use/share this pixelRef in the image
-extern SkImage* SkNewImageFromPixelRef(const SkImageInfo&, SkPixelRef*,
-                                       size_t rowBytes);
+extern SkImage* SkNewImageFromPixelRef(SkPixelRef*);
 
 /**
  *  Examines the bitmap to decide if it can share the existing pixelRef, or
diff --git a/src/image/SkImage_Base.h b/src/image/SkImage_Base.h
index 7bd1f7e6c9..5574f451fe 100644
--- a/src/image/SkImage_Base.h
+++ b/src/image/SkImage_Base.h
@@ -13,6 +13,7 @@
 class SkImage_Base : public SkImage {
 public:
     SkImage_Base(int width, int height) : INHERITED(width, height) {}
+    SkImage_Base(const SkImageInfo& info) : INHERITED(info.fWidth, info.fHeight) {}
 
     virtual void onDraw(SkCanvas*, SkScalar x, SkScalar y, const SkPaint*) = 0;
     virtual void onDrawRectToRect(SkCanvas*, const SkRect* src,
diff --git a/src/image/SkImage_Raster.cpp b/src/image/SkImage_Raster.cpp
index 32d53fc52e..b80fbb3a54 100644
--- a/src/image/SkImage_Raster.cpp
+++ b/src/image/SkImage_Raster.cpp
@@ -58,7 +58,7 @@ public:
     virtual bool getROPixels(SkBitmap*) const SK_OVERRIDE;
 
     // exposed for SkSurface_Raster via SkNewImageFromPixelRef
-    SkImage_Raster(const SkImageInfo&, SkPixelRef*, size_t rowBytes);
+    SkImage_Raster(SkPixelRef*);
 
     SkPixelRef* getPixelRef() const { return fBitmap.pixelRef(); }
 
@@ -84,18 +84,16 @@ SkImage* SkImage_Raster::NewEmpty() {
 
 SkImage_Raster::SkImage_Raster(const Info& info, SkData* data, size_t rowBytes)
         : INHERITED(info.fWidth, info.fHeight) {
-    fBitmap.setConfig(info, rowBytes);
     SkAutoTUnref<SkPixelRef> ref(
         SkMallocPixelRef::NewWithData(info, rowBytes, NULL, data, 0));
-    fBitmap.setPixelRef(ref);
+    fBitmap.installPixelRef(ref);
     fBitmap.setImmutable();
 }
 
-SkImage_Raster::SkImage_Raster(const Info& info, SkPixelRef* pr, size_t rowBytes)
-    : INHERITED(info.fWidth, info.fHeight)
+SkImage_Raster::SkImage_Raster(SkPixelRef* pr)
+    : INHERITED(pr->info())
 {
-    fBitmap.setConfig(info, rowBytes);
-    fBitmap.setPixelRef(pr);
+    fBitmap.installPixelRef(pr);
 }
 
 SkImage_Raster::~SkImage_Raster() {}
@@ -155,9 +153,8 @@ SkImage* SkImage::NewRasterData(const SkImageInfo& info, SkData* pixelData, size
     return SkNEW_ARGS(SkImage_Raster, (info, data, rowBytes));
 }
 
-SkImage* SkNewImageFromPixelRef(const SkImageInfo& info, SkPixelRef* pr,
-                                size_t rowBytes) {
-    return SkNEW_ARGS(SkImage_Raster, (info, pr, rowBytes));
+SkImage* SkNewImageFromPixelRef(SkPixelRef* pr) {
+    return SkNEW_ARGS(SkImage_Raster, (pr));
 }
 
 SkPixelRef* SkBitmapImageGetPixelRef(SkImage* image) {
diff --git a/src/image/SkSurface_Raster.cpp b/src/image/SkSurface_Raster.cpp
index 1b218eb446..7010b5fb2a 100644
--- a/src/image/SkSurface_Raster.cpp
+++ b/src/image/SkSurface_Raster.cpp
@@ -85,15 +85,12 @@ SkSurface_Raster::SkSurface_Raster(const SkImageInfo& info, void* pixels, size_t
 }
 
 SkSurface_Raster::SkSurface_Raster(SkPixelRef* pr)
-    : INHERITED(pr->info().fWidth, pr->info().fHeight)
+    : INHERITED(pr->info())
 {
-    const SkImageInfo& info = pr->info();
-
-    fBitmap.setConfig(info, info.minRowBytes());
-    fBitmap.setPixelRef(pr);
+    fBitmap.installPixelRef(pr);
     fWeOwnThePixels = true;
 
-    if (!info.isOpaque()) {
+    if (!pr->info().isOpaque()) {
         fBitmap.eraseColor(SK_ColorTRANSPARENT);
     }
 }
diff --git a/src/lazy/SkCachingPixelRef.cpp b/src/lazy/SkCachingPixelRef.cpp
index f1510fb67c..f5026c7365 100644
--- a/src/lazy/SkCachingPixelRef.cpp
+++ b/src/lazy/SkCachingPixelRef.cpp
@@ -12,15 +12,13 @@ bool SkCachingPixelRef::Install(SkImageGenerator* generator,
                                 SkBitmap* dst) {
     SkImageInfo info;
     SkASSERT(dst != NULL);
-    if ((NULL == generator)
-        || !(generator->getInfo(&info))
-        || !dst->setConfig(info, 0)) {
+    if (!generator || !generator->getInfo(&info)) {
         SkDELETE(generator);
         return false;
     }
     SkAutoTUnref<SkCachingPixelRef> ref(SkNEW_ARGS(SkCachingPixelRef,
                                            (info, generator, dst->rowBytes())));
-    dst->setPixelRef(ref);
+    dst->installPixelRef(ref);
     return true;
 }
 
diff --git a/src/lazy/SkDiscardablePixelRef.cpp b/src/lazy/SkDiscardablePixelRef.cpp
index abd80f2e0a..eb5c2f9ab3 100644
--- a/src/lazy/SkDiscardablePixelRef.cpp
+++ b/src/lazy/SkDiscardablePixelRef.cpp
@@ -94,6 +94,6 @@ bool SkInstallDiscardablePixelRef(SkImageGenerator* generator,
     SkAutoTUnref<SkDiscardablePixelRef> ref(
         SkNEW_ARGS(SkDiscardablePixelRef,
                    (info, autoGenerator.detach(), dst->rowBytes(), factory)));
-    dst->setPixelRef(ref);
+    dst->installPixelRef(ref);
     return true;
 }
diff --git a/tests/MallocPixelRefTest.cpp b/tests/MallocPixelRefTest.cpp
index e169763dad..62d1e9d687 100644
--- a/tests/MallocPixelRefTest.cpp
+++ b/tests/MallocPixelRefTest.cpp
@@ -23,7 +23,7 @@ static void set_to_one_proc(void*, void* context) {
  */
 DEF_TEST(MallocPixelRef, reporter) {
     REPORTER_ASSERT(reporter, true);
-    SkImageInfo info = {10, 13, kPMColor_SkColorType, kPremul_SkAlphaType};
+    SkImageInfo info = SkImageInfo::MakePMPremul(10, 13);
     {
         SkAutoTUnref<SkMallocPixelRef> pr(
             SkMallocPixelRef::NewAllocate(info, info.minRowBytes() - 1, NULL));
diff --git a/tests/PixelRefTest.cpp b/tests/PixelRefTest.cpp
index e0ffd7a601..3486898239 100644
--- a/tests/PixelRefTest.cpp
+++ b/tests/PixelRefTest.cpp
@@ -51,7 +51,7 @@ private:
 }  // namespace
 
 DEF_TEST(PixelRef_GenIDChange, r) {
-    SkImageInfo info = { 10, 10, kPMColor_SkColorType, kPremul_SkAlphaType };
+    SkImageInfo info = SkImageInfo::MakePMPremul(10, 10);
 
     SkAutoTUnref<SkPixelRef> pixelRef(SkMallocPixelRef::NewAllocate(info, 0, NULL));