Set maximum output size for scaled-image-cache images

include/core/SkGraphics.h

 
 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkGraphics_DEFINED
@@ skipping 66 matching lines @@
      *  does not change the limit, but will cause subsequent font measures and
      *  draws to be recreated, since they will no longer be in the cache.
      */
     static void PurgeFontCache();
 
     static size_t GetImageCacheBytesUsed();
     static size_t GetImageCacheByteLimit();
     static size_t SetImageCacheByteLimit(size_t newLimit);
 
     /**
+     *  Scaling bitmaps with the SkPaint::kHigh_FilterLevel setting is
+     *  expensive, so the result is saved in the global Scaled Image
+     *  Cache.  When the resulting bitmap is too large, this can
+     *  overload the cache.  If the ImageCacheSingleAllocationByteLimit
+     *  is set to a non-zero number, and the resulting bitmap would be
+     *  larger than that value, the bitmap scaling algorithm falls
+     *  back onto a cheaper algorithm and does not cache the result.
+     *  Zero is the default value.
+     */
+    static size_t GetImageCacheSingleAllocationByteLimit();
+    static size_t SetImageCacheSingleAllocationByteLimit(size_t newLimit);

[reveman, 2014/07/16 20:38:04]

I know this only affects pre-scaling of images and the comment also makes it
clear. The name of the function itself doesn't make this clear though.
SetImageCacheSingleAllocationByteLimit sounds like it might affect more than
pre-scaling. For example, decoded images and I wouldn't want to set this limit
in chrome if that was the case.

Maybe we just need some general comment making it clear that all these
"ImageCache" functions control caching of pre-scaled images.

Not a big deal, just wanted to point it out. As long as this does what we need,
I'm OK with it.

+
+    /**
      *  Applications with command line options may pass optional state, such
      *  as cache sizes, here, for instance:
      *  font-cache-limit=12345678
      *
      *  The flags format is name=value[;name=value...] with no spaces.
      *  This format is subject to change.
      */
     static void SetFlags(const char* flags);
 
     /**
@@ skipping 28 matching lines @@
 public:
     SkAutoGraphics() {
         SkGraphics::Init();
     }
     ~SkAutoGraphics() {
         SkGraphics::Term();
     }
 };
 
 #endif