Reland DeferredTextureImageData low-bit-depth/dithering support

Cause DeferredTextureImageData functionality to support low bit depth
(4444, 565) image formats (with dithering).

Updated to handle colorspace + 4444 colortype correctly.

Bug: 720105
Change-Id: Ib7e14d937849f4f6b08fda6992a240bb203d0089
Reviewed-on: https://skia-review.googlesource.com/19094
Commit-Queue: Eric Karl <ericrk@chromium.org>
Reviewed-by: Brian Salomon <bsalomon@google.com>

2 files changed, 15 insertions, 0 deletions

diff --git a/src/core/SkAutoPixmapStorage.cpp b/src/core/SkAutoPixmapStorage.cpp
index 865b3a6029..5ad19390c6 100644
--- a/src/core/SkAutoPixmapStorage.cpp
+++ b/src/core/SkAutoPixmapStorage.cpp
@@ -14,6 +14,16 @@ SkAutoPixmapStorage::~SkAutoPixmapStorage() {
     this->freeStorage();
 }
 
+SkAutoPixmapStorage& SkAutoPixmapStorage::operator=(SkAutoPixmapStorage&& other) {
+    this->fStorage = other.fStorage;
+    this->INHERITED::reset(other.info(), this->fStorage, other.rowBytes(), other.ctable());
+
+    other.fStorage = nullptr;
+    other.INHERITED::reset();
+
+    return *this;
+}
+
 size_t SkAutoPixmapStorage::AllocSize(const SkImageInfo& info, size_t* rowBytes) {
     size_t rb = info.minRowBytes();
     if (rowBytes) {
diff --git a/src/core/SkAutoPixmapStorage.h b/src/core/SkAutoPixmapStorage.h
index 66c5655e54..6342a41deb 100644
--- a/src/core/SkAutoPixmapStorage.h
+++ b/src/core/SkAutoPixmapStorage.h
@@ -17,6 +17,11 @@ public:
     ~SkAutoPixmapStorage();
 
     /**
+    * Leave the moved-from object in a free-but-valid state.
+    */
+    SkAutoPixmapStorage& operator=(SkAutoPixmapStorage&& other);
+
+    /**
     *  Try to allocate memory for the pixels needed to match the specified Info. On success
     *  return true and fill out the pixmap to point to that memory. The storage will be freed
     *  when this object is destroyed, or if another call to tryAlloc() or alloc() is made.