The Tor Browser: comparison gfx/2d/image

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+:c770e8a1280b
+// 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/SkTypes.h"
+#include "Types.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);
+};
+}  // namespace skia
+#endif  // SKIA_EXT_IMAGE_OPERATIONS_H_

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comparison: gfx/2d/image_operations.h

gfx/2d/image_operations.h