1/*
2 * Copyright (C) 2006, 2007, 2008 Apple Inc.  All rights reserved.
3 * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
15 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
17 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
18 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
19 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
20 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
21 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
22 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include "config.h"
28#include "Pattern.h"
29
30#include "AffineTransform.h"
31#include "GraphicsContext.h"
32
33#include <CoreGraphics/CoreGraphics.h>
34#include <wtf/MainThread.h>
35
36#if PLATFORM(COCOA)
37#include "WebCoreSystemInterface.h"
38#endif
39
40#if PLATFORM(WIN)
41#include <WebKitSystemInterface/WebKitSystemInterface.h>
42#endif
43
44namespace WebCore {
45
46static void patternCallback(void* info, CGContextRef context)
47{
48    CGImageRef platformImage = static_cast<CGImageRef>(info);
49    if (!platformImage)
50        return;
51
52    CGRect rect = GraphicsContext(context).roundToDevicePixels(
53        FloatRect(0, 0, CGImageGetWidth(platformImage), CGImageGetHeight(platformImage)));
54    CGContextDrawImage(context, rect, platformImage);
55}
56
57static void patternReleaseOnMainThreadCallback(void* info)
58{
59    CGImageRelease(static_cast<CGImageRef>(info));
60}
61
62static void patternReleaseCallback(void* info)
63{
64    callOnMainThread(patternReleaseOnMainThreadCallback, info);
65}
66
67CGPatternRef Pattern::createPlatformPattern(const AffineTransform& userSpaceTransformation) const
68{
69    FloatRect tileRect = tileImage()->rect();
70
71    AffineTransform patternTransform = userSpaceTransformation * m_patternSpaceTransformation;
72    patternTransform.scaleNonUniform(1, -1);
73    patternTransform.translate(0, -tileRect.height());
74
75    // If we're repeating in both directions, we can use image-backed patterns
76    // instead of custom patterns, and avoid tiling-edge pixel cracks.
77    if (m_repeatX && m_repeatY)
78        return wkCGPatternCreateWithImageAndTransform(tileImage()->getCGImageRef(), patternTransform, wkPatternTilingConstantSpacing);
79
80    // If FLT_MAX should also be used for xStep or yStep, nothing is rendered. Using fractions of FLT_MAX also
81    // result in nothing being rendered.
82    // INT_MAX is almost correct, but there seems to be some number wrapping occurring making the fill
83    // pattern is not filled correctly.
84    // To make error of floating point less than 0.5, we use the half of the number of mantissa of float (1 << 22).
85    CGFloat xStep = m_repeatX ? tileRect.width() : (1 << 22);
86    CGFloat yStep = m_repeatY ? tileRect.height() : (1 << 22);
87
88    // The pattern will release the CGImageRef when it's done rendering in patternReleaseCallback
89    CGImageRef platformImage = CGImageRetain(tileImage()->getCGImageRef());
90
91    const CGPatternCallbacks patternCallbacks = { 0, patternCallback, patternReleaseCallback };
92    return CGPatternCreate(platformImage, tileRect, patternTransform, xStep, yStep, kCGPatternTilingConstantSpacing, TRUE, &patternCallbacks);
93}
94
95}
96