Add m-esr52 at 52.6.0

1 files changed, 285 insertions, 0 deletions

diff --git a/gfx/2d/image_operations.h b/gfx/2d/image_operations.h
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+// Copyright (c) 2006-2011 The Chromium Authors. All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions
+// are met:
+//  * Redistributions of source code must retain the above copyright
+//    notice, this list of conditions and the following disclaimer.
+//  * Redistributions in binary form must reproduce the above copyright
+//    notice, this list of conditions and the following disclaimer in
+//    the documentation and/or other materials provided with the
+//    distribution.
+//  * Neither the name of Google, Inc. nor the names of its contributors
+//    may be used to endorse or promote products derived from this
+//    software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+// COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+// OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+// AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+// OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+// SUCH DAMAGE.
+
+#ifndef SKIA_EXT_IMAGE_OPERATIONS_H_
+#define SKIA_EXT_IMAGE_OPERATIONS_H_
+
+#include "skia/include/core/SkTypes.h"
+#include "Types.h"
+#include "convolver.h"
+#include "skia/include/core/SkRect.h"
+
+class SkBitmap;
+struct SkIRect;
+
+namespace skia {
+
+class ImageOperations {
+ 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,
+
+    // 1-cycle Hamming filter. This is tall is the middle and falls off towards
+    // the window edges but without going to 0. This is about 40% faster than
+    // a 2-cycle Lanczos.
+    RESIZE_HAMMING1,
+
+    // 2-cycle Lanczos filter. This is tall in the middle, goes negative on
+    // each side, then returns to zero. Does not provide as good a frequency
+    // response as a 3-cycle Lanczos but is roughly 30% faster.
+    RESIZE_LANCZOS2,
+
+    // 3-cycle Lanczos filter. This is tall in the middle, goes negative on
+    // each side, then oscillates 2 more times. It gives nice sharp edges.
+    RESIZE_LANCZOS3,
+
+    // Lanczos filter + subpixel interpolation. If subpixel rendering is not
+    // appropriate we automatically fall back to Lanczos.
+    RESIZE_SUBPIXEL,
+
+    // 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_SUBPIXEL,
+  };
+
+  // Resizes the given source bitmap using the specified resize method, so that
+  // the entire image is (dest_size) big. The dest_subset is the rectangle in
+  // this destination image that should actually be returned.
+  //
+  // The output image will be (dest_subset.width(), dest_subset.height()). This
+  // will save work if you do not need the entire bitmap.
+  //
+  // The destination subset must be smaller than the destination image.
+  static SkBitmap Resize(const SkBitmap& source,
+                         ResizeMethod method,
+                         int dest_width, int dest_height,
+                         const SkIRect& dest_subset,
+                         void* dest_pixels = nullptr);
+
+  // Alternate version for resizing and returning the entire bitmap rather than
+  // a subset.
+  static SkBitmap Resize(const SkBitmap& source,
+                         ResizeMethod method,
+                         int dest_width, int dest_height,
+                         void* dest_pixels = nullptr);
+
+ private:
+  ImageOperations();  // Class for scoping only.
+
+  // Supports all methods except RESIZE_SUBPIXEL.
+  static SkBitmap ResizeBasic(const SkBitmap& source,
+                              ResizeMethod method,
+                              int dest_width, int dest_height,
+                              const SkIRect& dest_subset,
+                              void* dest_pixels = nullptr);
+
+  // Subpixel renderer.
+  static SkBitmap ResizeSubpixel(const SkBitmap& source,
+                                 int dest_width, int dest_height,
+                                 const SkIRect& dest_subset);
+};
+
+// Returns the ceiling/floor as an integer.
+inline int CeilInt(float val) {
+  return static_cast<int>(ceil(val));
+}
+inline int FloorInt(float val) {
+  return static_cast<int>(floor(val));
+}
+
+// Filter function computation -------------------------------------------------
+
+// Evaluates the box filter, which goes from -0.5 to +0.5.
+inline float EvalBox(float x) {
+  return (x >= -0.5f && x < 0.5f) ? 1.0f : 0.0f;
+}
+
+// Evaluates the Lanczos filter of the given filter size window for the given
+// position.
+//
+// |filter_size| is the width of the filter (the "window"), outside of which
+// the value of the function is 0. Inside of the window, the value is the
+// normalized sinc function:
+//   lanczos(x) = sinc(x) * sinc(x / filter_size);
+// where
+//   sinc(x) = sin(pi*x) / (pi*x);
+inline float EvalLanczos(int filter_size, float x) {
+  if (x <= -filter_size || x >= filter_size)
+    return 0.0f;  // Outside of the window.
+  if (x > -std::numeric_limits<float>::epsilon() &&
+      x < std::numeric_limits<float>::epsilon())
+    return 1.0f;  // Special case the discontinuity at the origin.
+  float xpi = x * static_cast<float>(M_PI);
+  return (sinf(xpi) / xpi) *  // sinc(x)
+          sinf(xpi / filter_size) / (xpi / filter_size);  // sinc(x/filter_size)
+}
+
+// Evaluates the Hamming filter of the given filter size window for the given
+// position.
+//
+// The filter covers [-filter_size, +filter_size]. Outside of this window
+// the value of the function is 0. Inside of the window, the value is sinus
+// cardinal multiplied by a recentered Hamming function. The traditional
+// Hamming formula for a window of size N and n ranging in [0, N-1] is:
+//   hamming(n) = 0.54 - 0.46 * cos(2 * pi * n / (N-1)))
+// In our case we want the function centered for x == 0 and at its minimum
+// on both ends of the window (x == +/- filter_size), hence the adjusted
+// formula:
+//   hamming(x) = (0.54 -
+//                 0.46 * cos(2 * pi * (x - filter_size)/ (2 * filter_size)))
+//              = 0.54 - 0.46 * cos(pi * x / filter_size - pi)
+//              = 0.54 + 0.46 * cos(pi * x / filter_size)
+inline float EvalHamming(int filter_size, float x) {
+  if (x <= -filter_size || x >= filter_size)
+    return 0.0f;  // Outside of the window.
+  if (x > -std::numeric_limits<float>::epsilon() &&
+      x < std::numeric_limits<float>::epsilon())
+    return 1.0f;  // Special case the sinc discontinuity at the origin.
+  const float xpi = x * static_cast<float>(M_PI);
+
+  return ((sinf(xpi) / xpi) *  // sinc(x)
+          (0.54f + 0.46f * cosf(xpi / filter_size)));  // hamming(x)
+}
+
+// ResizeFilter ----------------------------------------------------------------
+
+// Encapsulates computation and storage of the filters required for one complete
+// resize operation.
+
+namespace resize {
+
+  // Returns the number of pixels that the filer spans, in filter space (the
+  // destination image).
+  inline float GetFilterSupport(ImageOperations::ResizeMethod method,
+                                float scale) {
+    switch (method) {
+      case ImageOperations::RESIZE_BOX:
+        // The box filter just scales with the image scaling.
+        return 0.5f;  // Only want one side of the filter = /2.
+      case ImageOperations::RESIZE_HAMMING1:
+        // The Hamming filter takes as much space in the source image in
+        // each direction as the size of the window = 1 for Hamming1.
+        return 1.0f;
+      case ImageOperations::RESIZE_LANCZOS2:
+        // The Lanczos filter takes as much space in the source image in
+        // each direction as the size of the window = 2 for Lanczos2.
+        return 2.0f;
+      case ImageOperations::RESIZE_LANCZOS3:
+        // The Lanczos filter takes as much space in the source image in
+        // each direction as the size of the window = 3 for Lanczos3.
+        return 3.0f;
+      default:
+        return 1.0f;
+    }
+  }
+
+  // Computes one set of filters either horizontally or vertically. The caller
+  // will specify the "min" and "max" rather than the bottom/top and
+  // right/bottom so that the same code can be re-used in each dimension.
+  //
+  // |src_depend_lo| and |src_depend_size| gives the range for the source
+  // depend rectangle (horizontally or vertically at the caller's discretion
+  // -- see above for what this means).
+  //
+  // Likewise, the range of destination values to compute and the scale factor
+  // for the transform is also specified.
+  void ComputeFilters(ImageOperations::ResizeMethod method,
+                      int src_size, int dst_size,
+                      int dest_subset_lo, int dest_subset_size,
+                      ConvolutionFilter1D* output);
+
+  // Computes the filter value given the coordinate in filter space.
+  inline float ComputeFilter(ImageOperations::ResizeMethod method, float pos) {
+    switch (method) {
+      case ImageOperations::RESIZE_BOX:
+        return EvalBox(pos);
+      case ImageOperations::RESIZE_HAMMING1:
+        return EvalHamming(1, pos);
+      case ImageOperations::RESIZE_LANCZOS2:
+        return EvalLanczos(2, pos);
+      case ImageOperations::RESIZE_LANCZOS3:
+        return EvalLanczos(3, pos);
+      default:
+        return 0;
+    }
+  }
+}
+
+}  // namespace skia
+
+#endif  // SKIA_EXT_IMAGE_OPERATIONS_H_