1 /*
2 * Copyright (c) 2008, Google Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are
6 * met:
7 *
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions and the following disclaimer
12 * in the documentation and/or other materials provided with the
13 * distribution.
14 * * Neither the name of Google Inc. nor the names of its
15 * contributors may be used to endorse or promote products derived from
16 * this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31 #include "config.h"
32
33 #if !PLATFORM(ANDROID)
34 #include "skia/ext/image_operations.h"
35 #endif
36
37 #include "NativeImageSkia.h"
38 #include "SkiaUtils.h"
39
NativeImageSkia()40 NativeImageSkia::NativeImageSkia()
41 : m_isDataComplete(false),
42 m_lastRequestSize(0, 0),
43 m_resizeRequests(0)
44 {
45 }
46
decodedSize() const47 int NativeImageSkia::decodedSize() const
48 {
49 return getSize() + m_resizedImage.getSize();
50 }
51
hasResizedBitmap(int w,int h) const52 bool NativeImageSkia::hasResizedBitmap(int w, int h) const
53 {
54 if (m_lastRequestSize.width() == w && m_lastRequestSize.height() == h)
55 m_resizeRequests++;
56 else {
57 m_lastRequestSize = WebCore::IntSize(w, h);
58 m_resizeRequests = 0;
59 }
60
61 return m_resizedImage.width() == w && m_resizedImage.height() == h;
62 }
63
64 // FIXME: don't cache when image is in-progress.
65
resizedBitmap(int w,int h) const66 SkBitmap NativeImageSkia::resizedBitmap(int w, int h) const
67 {
68 #if !PLATFORM(ANDROID)
69 if (m_resizedImage.width() != w || m_resizedImage.height() != h)
70 m_resizedImage = skia::ImageOperations::Resize(*this, skia::ImageOperations::RESIZE_LANCZOS3, w, h);
71 #endif
72
73 return m_resizedImage;
74 }
75
shouldCacheResampling(int destWidth,int destHeight,int destSubsetWidth,int destSubsetHeight) const76 bool NativeImageSkia::shouldCacheResampling(int destWidth,
77 int destHeight,
78 int destSubsetWidth,
79 int destSubsetHeight) const
80 {
81 // We can not cache incomplete frames. This might be a good optimization in
82 // the future, were we know how much of the frame has been decoded, so when
83 // we incrementally draw more of the image, we only have to resample the
84 // parts that are changed.
85 if (!m_isDataComplete)
86 return false;
87
88 // If the destination bitmap is small, we'll always allow caching, since
89 // there is not very much penalty for computing it and it may come in handy.
90 static const int kSmallBitmapSize = 4096;
91 if (destWidth * destHeight <= kSmallBitmapSize)
92 return true;
93
94 // If "too many" requests have been made for this bitmap, we assume that
95 // many more will be made as well, and we'll go ahead and cache it.
96 static const int kManyRequestThreshold = 4;
97 if (m_lastRequestSize.width() == destWidth &&
98 m_lastRequestSize.height() == destHeight) {
99 if (m_resizeRequests >= kManyRequestThreshold)
100 return true;
101 } else {
102 // When a different size is being requested, count this as a query
103 // (hasResizedBitmap) and reset the counter.
104 m_lastRequestSize = WebCore::IntSize(destWidth, destHeight);
105 m_resizeRequests = 0;
106 }
107
108 // Otherwise, use the heuristic that if more than 1/4 of the image is
109 // requested, it's worth caching.
110 int destSize = destWidth * destHeight;
111 int destSubsetSize = destSubsetWidth * destSubsetHeight;
112 return destSize / 4 < destSubsetSize;
113 }
114