Update SkSpecialImage to be able to create tight SkImages and SkSurfaces

tests/SpecialImageTest.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 "SkAutoPixmapStorage.h"
 #include "SkBitmap.h"
 #include "SkCanvas.h"
 #include "SkImage.h"
 #include "SkPixmap.h"
 #include "SkSpecialImage.h"
 #include "SkSpecialSurface.h"
+#include "SkSurface.h"
 #include "Test.h"
 #include "TestingSpecialImageAccess.h"
 
 #if SK_SUPPORT_GPU
 #include "GrContext.h"
 #endif
 
 
 // This test creates backing resources exactly sized to [kFullSize x kFullSize].
 // It then wraps them in an SkSpecialImage with only the center (red) region being active.
@@ skipping 27 matching lines @@
 static void test_image(const sk_sp<SkSpecialImage>& img, skiatest::Reporter* reporter,
                        bool peekPixelsSucceeds, bool peekTextureSucceeds,
                        int offset, int size) {
     const SkIRect subset = TestingSpecialImageAccess::Subset(img.get());
     REPORTER_ASSERT(reporter, offset == subset.left());
     REPORTER_ASSERT(reporter, offset == subset.top());
     REPORTER_ASSERT(reporter, kSmallerSize == subset.width());
     REPORTER_ASSERT(reporter, kSmallerSize == subset.height());
 
     //--------------
+    // Test that peekTexture reports the correct backing type
     REPORTER_ASSERT(reporter, peekTextureSucceeds ==
                                         !!TestingSpecialImageAccess::PeekTexture(img.get()));
 
     //--------------
+    // Test that peekPixels reports the correct backing type
     SkPixmap pixmap;
     REPORTER_ASSERT(reporter, peekPixelsSucceeds ==
                               !!TestingSpecialImageAccess::PeekPixels(img.get(), &pixmap));
     if (peekPixelsSucceeds) {
         REPORTER_ASSERT(reporter, size == pixmap.width());
         REPORTER_ASSERT(reporter, size == pixmap.height());
     }
 
     //--------------
+    // Test that draw restricts itself to the subset
     SkImageInfo info = SkImageInfo::MakeN32(kFullSize, kFullSize, kOpaque_SkAlphaType);
 
     sk_sp<SkSpecialSurface> surf(img->makeSurface(info));
 
     SkCanvas* canvas = surf->getCanvas();
 
     canvas->clear(SK_ColorBLUE);
     img->draw(canvas, SkIntToScalar(kPad), SkIntToScalar(kPad), nullptr);
 
     SkBitmap bm;
     bm.allocN32Pixels(kFullSize, kFullSize, true);
 
     bool result = canvas->readPixels(bm.info(), bm.getPixels(), bm.rowBytes(), 0, 0);
     SkASSERT_RELEASE(result);
 
     // Only the center (red) portion should've been drawn into the canvas
     REPORTER_ASSERT(reporter, SK_ColorBLUE == bm.getColor(kPad-1, kPad-1));
     REPORTER_ASSERT(reporter, SK_ColorRED  == bm.getColor(kPad, kPad));
     REPORTER_ASSERT(reporter, SK_ColorRED  == bm.getColor(kSmallerSize+kPad-1,
                                                           kSmallerSize+kPad-1));
     REPORTER_ASSERT(reporter, SK_ColorBLUE == bm.getColor(kSmallerSize+kPad,
                                                           kSmallerSize+kPad));
+
+    //--------------
+    // Test that makeTightSubset & makeTightSurface return appropriately sized objects
+    // of the correct backing type
+    SkIRect newSubset = SkIRect::MakeWH(subset.width(), subset.height());
+    {
+        sk_sp<SkImage> tightImg(img->makeTightSubset(newSubset));
+
+        REPORTER_ASSERT(reporter, tightImg->width() == subset.width());
+        REPORTER_ASSERT(reporter, tightImg->height() == subset.height());
+        REPORTER_ASSERT(reporter, peekTextureSucceeds == !!tightImg->getTexture());
+        SkPixmap tmpPixmap;
+        REPORTER_ASSERT(reporter, peekPixelsSucceeds == !!tightImg->peekPixels(&tmpPixmap));
+    }
+    {
+        SkImageInfo info = SkImageInfo::MakeN32(subset.width(), subset.height(),
+                                                kPremul_SkAlphaType);
+        sk_sp<SkSurface> tightSurf(img->makeTightSurface(info));
+
+        REPORTER_ASSERT(reporter, tightSurf->width() == subset.width());
+        REPORTER_ASSERT(reporter, tightSurf->height() == subset.height());
+        REPORTER_ASSERT(reporter, peekTextureSucceeds ==
+                     !!tightSurf->getTextureHandle(SkSurface::kDiscardWrite_BackendHandleAccess));
+        SkPixmap tmpPixmap;
+        REPORTER_ASSERT(reporter, peekPixelsSucceeds == !!tightSurf->peekPixels(&tmpPixmap));
+    }
 }
 
 DEF_TEST(SpecialImage_Raster, reporter) {
     SkBitmap bm = create_bm();
 
     sk_sp<SkSpecialImage> fullSImage(SkSpecialImage::MakeFromRaster(
                                                             nullptr,
                                                             SkIRect::MakeWH(kFullSize, kFullSize),
                                                             bm));
 
@@ skipping 174 matching lines @@
         test_image(subSImg1, reporter, false, true, kPad, kFullSize);
     }
 
     {
         sk_sp<SkSpecialImage> subSImg2(fullSImg->makeSubset(subset));
         test_image(subSImg2, reporter, false, true, kPad, kFullSize);
     }
 }
 
 #endif