use special-image for imagefilters and save/restore layer

src/core/SkSpecialImage.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file
  */
 #include "SkSpecialImage.h"
 
 #if SK_SUPPORT_GPU
 #include "GrTexture.h"
 #include "GrTextureParams.h"
 #include "SkGr.h"
 #endif
 
 #include "SkBitmapCache.h"
 #include "SkCanvas.h"
 #include "SkImage_Base.h"
 #include "SkSpecialSurface.h"
 #include "SkSurfacePriv.h"
 
+// Currently the raster imagefilters can only handle certain imageinfos. Call this to know if
+// a given info is supported.
+static bool valid_for_imagefilters(const SkImageInfo& info) {
+    // no support for other swizzles/depths yet
+    return info.colorType() == kN32_SkColorType;
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 class SkSpecialImage_Base : public SkSpecialImage {
 public:
     SkSpecialImage_Base(const SkIRect& subset, uint32_t uniqueID, const SkSurfaceProps* props)
         : INHERITED(subset, uniqueID, props) {
     }
     ~SkSpecialImage_Base() override { }
 
     virtual void onDraw(SkCanvas*, SkScalar x, SkScalar y, const SkPaint*) const = 0;
 
@@ skipping 277 matching lines @@
            rect.fTop >= 0 && rect.fTop < height && rect.fTop < rect.fBottom &&
            rect.fBottom >= 0 && rect.fBottom <= height;
 }
 #endif
 
 sk_sp<SkSpecialImage> SkSpecialImage::MakeFromImage(const SkIRect& subset,
                                                     sk_sp<SkImage> image,
                                                     const SkSurfaceProps* props) {
     SkASSERT(rect_fits(subset, image->width(), image->height()));
 
-    return sk_make_sp<SkSpecialImage_Image>(subset, image, props);
+    if (valid_for_imagefilters(as_IB(image.get())->onImageInfo())) {
+        return sk_make_sp<SkSpecialImage_Image>(subset, image, props);
+    } else {
+        return nullptr;
+    }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 #include "SkBitmap.h"
 #include "SkImageInfo.h"
 #include "SkPixelRef.h"
 
 class SkSpecialImage_Raster : public SkSpecialImage_Base {
 public:
     SkSpecialImage_Raster(const SkIRect& subset, const SkBitmap& bm, const SkSurfaceProps* props)
@@ skipping 76 matching lines @@
 
     typedef SkSpecialImage_Base INHERITED;
 };
 
 sk_sp<SkSpecialImage> SkSpecialImage::MakeFromRaster(const SkIRect& subset,
                                                      const SkBitmap& bm,
                                                      const SkSurfaceProps* props) {
     SkASSERT(nullptr == bm.getTexture());
     SkASSERT(rect_fits(subset, bm.width(), bm.height()));
 
-    return sk_make_sp<SkSpecialImage_Raster>(subset, bm, props);
+    const SkBitmap* srcBM = &bm;
+    SkBitmap tmpStorage;
+    // ImageFilters only handle N32 at the moment, so force our src to be that
+    if (!valid_for_imagefilters(bm.info())) {
+        if (!bm.copyTo(&tmpStorage, kN32_SkColorType)) {
+            return nullptr;
+        }
+        srcBM = &tmpStorage;
+    }
+    return sk_make_sp<SkSpecialImage_Raster>(subset, *srcBM, props);
 }
 
 #if SK_SUPPORT_GPU
 ///////////////////////////////////////////////////////////////////////////////
 #include "GrTexture.h"
 #include "SkImage_Gpu.h"
 
 class SkSpecialImage_Gpu : public SkSpecialImage_Base {
 public:
     SkSpecialImage_Gpu(const SkIRect& subset,
@@ skipping 134 matching lines @@
 sk_sp<SkSpecialImage> SkSpecialImage::MakeFromGpu(const SkIRect& subset,
                                                   uint32_t uniqueID,
                                                   sk_sp<GrTexture> tex,
                                                   const SkSurfaceProps* props,
                                                   SkAlphaType at) {
     SkASSERT(rect_fits(subset, tex->width(), tex->height()));
     return sk_make_sp<SkSpecialImage_Gpu>(subset, uniqueID, std::move(tex), at, props);
 }
 
 #endif