1/*
2 * Copyright (C) 2010 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
6 * are met:
7 *
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 AND ITS CONTRIBUTORS "AS IS" AND ANY
15 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
16 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
17 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
18 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
19 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
20 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
21 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef ImageOrientation_h
27#define ImageOrientation_h
28
29#include "platform/PlatformExport.h"
30
31namespace blink {
32
33class AffineTransform;
34class FloatSize;
35
36// This enum intentionally matches the orientation values from the EXIF spec.
37// See JEITA CP-3451, page 18. http://www.exif.org/Exif2-2.PDF
38enum ImageOrientationEnum {
39    // "TopLeft" means that the 0 row starts at the Top, the 0 column starts at the Left.
40    OriginTopLeft = 1, // default
41    OriginTopRight = 2, // mirror along y-axis
42    OriginBottomRight = 3, // 180 degree rotation
43    OriginBottomLeft = 4, // mirror along the x-axis
44    OriginLeftTop = 5, // mirror along x-axis + 270 degree CW rotation
45    OriginRightTop = 6, // 90 degree CW rotation
46    OriginRightBottom = 7, // mirror along x-axis + 90 degree CW rotation
47    OriginLeftBottom = 8, // 270 degree CW rotation
48    // All other values are "reserved" as of EXIF 2.2
49    DefaultImageOrientation = OriginTopLeft,
50};
51
52enum RespectImageOrientationEnum {
53    DoNotRespectImageOrientation = 0,
54    RespectImageOrientation = 1
55};
56
57class PLATFORM_EXPORT ImageOrientation {
58public:
59    ImageOrientation(ImageOrientationEnum orientation = DefaultImageOrientation)
60        : m_orientation(orientation)
61    {
62    }
63
64    bool usesWidthAsHeight() const
65    {
66        // Values 5 through 8 all flip the width/height.
67        return m_orientation >= OriginLeftTop;
68    }
69
70    // ImageOrientationEnum currently matches EXIF values, however code outside
71    // this function should never assume that.
72    static ImageOrientation fromEXIFValue(int exifValue)
73    {
74        // Values direct from images may be invalid, in which case we use the default.
75        if (exifValue < OriginTopLeft || exifValue > OriginLeftBottom)
76            return DefaultImageOrientation;
77        return static_cast<ImageOrientationEnum>(exifValue);
78    }
79
80    // This transform can be used for drawing an image according to the orientation.
81    // It should be used in a right-handed coordinate system.
82    AffineTransform transformFromDefault(const FloatSize& drawnSize) const;
83
84    inline bool operator==(const ImageOrientation& other) const { return other.m_orientation == m_orientation; }
85    inline bool operator!=(const ImageOrientation& other) const { return !(*this == other); }
86
87private:
88    // FIXME: This only needs to be one byte.
89    ImageOrientationEnum m_orientation;
90};
91
92} // namespace blink
93
94#endif // ImageOrientation_h
95