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      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 
     31 namespace WebCore {
     32 
     33 class AffineTransform;
     34 class 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
     38 enum 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 
     52 enum RespectImageOrientationEnum {
     53     DoNotRespectImageOrientation = 0,
     54     RespectImageOrientation = 1
     55 };
     56 
     57 class PLATFORM_EXPORT ImageOrientation {
     58 public:
     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 
     87 private:
     88     // FIXME: This only needs to be one byte.
     89     ImageOrientationEnum m_orientation;
     90 };
     91 
     92 } // namespace WebCore
     93 
     94 #endif // ImageOrientation_h
     95