simplify bitmap scaler and cache

src/core/SkBitmapScaler.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkBitmapScaler_DEFINED
 #define SkBitmapScaler_DEFINED
 
 #include "SkBitmap.h"
 #include "SkConvolver.h"
 
 /** \class SkBitmapScaler
 
     Provides the interface for high quality image resampling.
  */
 
 class SK_API SkBitmapScaler {
 public:
     enum ResizeMethod {
-        // Quality Methods
-        //
-        // Those enumeration values express a desired quality/speed tradeoff.
-        // They are translated into an algorithm-specific method that depends
-        // on the capabilities (CPU, GPU) of the underlying platform.
-        // It is possible for all three methods to be mapped to the same
-        // algorithm on a given platform.
-
-        // Good quality resizing. Fastest resizing with acceptable visual quality.
-        // This is typically intended for use during interactive layouts
-        // where slower platforms may want to trade image quality for large
-        // increase in resizing performance.
-        //
-        // For example the resizing implementation may devolve to linear
-        // filtering if this enables GPU acceleration to be used.
-        //
-        // Note that the underlying resizing method may be determined
-        // on the fly based on the parameters for a given resize call.
-        // For example an implementation using a GPU-based linear filter
-        // in the common case may still use a higher-quality software-based
-        // filter in cases where using the GPU would actually be slower - due
-        // to too much latency - or impossible - due to image format or size
-        // constraints.
-        RESIZE_GOOD,
-
-        // Medium quality resizing. Close to high quality resizing (better
-        // than linear interpolation) with potentially some quality being
-        // traded-off for additional speed compared to RESIZE_BEST.
-        //
-        // This is intended, for example, for generation of large thumbnails
-        // (hundreds of pixels in each dimension) from large sources, where
-        // a linear filter would produce too many artifacts but where
-        // a RESIZE_HIGH might be too costly time-wise.
-        RESIZE_BETTER,
-
-        // High quality resizing. The algorithm is picked to favor image quality.
-        RESIZE_BEST,
-
-        //
-        // Algorithm-specific enumerations
-        //
-
-        // Box filter. This is a weighted average of all of the pixels touching
-        // the destination pixel. For enlargement, this is nearest neighbor.
-        //
-        // You probably don't want this, it is here for testing since it is easy to
-        // compute. Use RESIZE_LANCZOS3 instead.
         RESIZE_BOX,
         RESIZE_TRIANGLE,
         RESIZE_LANCZOS3,
         RESIZE_HAMMING,
         RESIZE_MITCHELL,
 
-        // enum aliases for first and last methods by algorithm or by quality.
-        RESIZE_FIRST_QUALITY_METHOD = RESIZE_GOOD,
-        RESIZE_LAST_QUALITY_METHOD = RESIZE_BEST,
-        RESIZE_FIRST_ALGORITHM_METHOD = RESIZE_BOX,
-        RESIZE_LAST_ALGORITHM_METHOD = RESIZE_MITCHELL,
+        RESIZE_FirstMethod = RESIZE_BOX,
+        RESIZE_LastMethod = RESIZE_MITCHELL,
     };
 
     static bool Resize(SkBitmap* result, const SkPixmap& src, ResizeMethod method,
-                       float dest_width, float dest_height, SkBitmap::Allocator* = nullptr);
+                       int dest_width, int dest_height, SkBitmap::Allocator* = nullptr);
 
      /** Platforms can also optionally overwrite the convolution functions
         if we have SIMD versions of them.
       */
 
     static void PlatformConvolutionProcs(SkConvolutionProcs*);
 };
 
 #endif