third_party/WebKit/Source/platform/graphics/ImageOrientation.h

   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 blink {
  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 blink
  93
  94 #endif // ImageOrientation_h