hydra.src/hydra/RotateCode.h

/*
 * Copyright (c) 2010 Aleksander B. Demko
 * This source code is distributed under the MIT license.
 * See the accompanying file LICENSE.MIT.txt for details.
 */

#ifndef __INCLUDED_HYDRA_ROTATETAG_H__
#define __INCLUDED_HYDRA_ROTATETAG_H__

#include <QImage>
#include <QPixmap>

#include <hydra/Records.h>

namespace hydra
{
  /**
   * Converts a rotate code to degrees, for display.
   *
   * @author Aleksander Demko
   */ 
  inline int rotateCodeToDegrees(int rotateCode) { return rotateCode * 90; }

  /**
   * Converts degrees to a rotate code.
   * Returns -1 on invalid codes.
   *
   * @author Aleksander Demko
   */
  int rotateDegreesToCode(int degrees);

  /**
   * Adds the given amount (which can be negative)o to the rotateCode
   * and returns the result.
   * The returned result is always valid (0..3)
   *
   * @author Aleksander Demko
   */ 
  int rotateCodeAdd(int rotateCode, int deltaCode);

  /**
   * Detects the auto rotation information in the file, if any.
   * -1 error/no exif found.
   * 0 do not rotate
   * 1 rotate 90 degrees cw
   * 2 rotate 180 degrees cw
   * 3 rotate 270 degrees cw
   *
   * If exif detection support is not compiled, this function will always return 0.
   *
   * @author Aleksander Demko
   */ 
  short detectTagRotate(const hydra::FileItemRecord::tags_t &tags);

  /**
   * Converts the given coordinates to the final coordinates, as if it where rotated by the given exif rotation
   * code. Node, the variables can the same (&origW == newW, etc)
   *
   * @author Aleksander Demko
   */ 
  void rotateSizeByCode(short rotatecode, unsigned long origW, unsigned long origH, unsigned long &newW, unsigned long &newH);

  /**
   * Rotates an image as per the given rotate code.
   * 0 do not rotate
   * 1 rotate 90 degrees cw
   * 2 rotate 180 degrees cw
   * 3 rotate 270 degrees cw
   * rotatecode must be >=0
   *
   * @author Aleksander Demko
   */
  QImage rotateImageByCode(short rotatecode, QImage &img);

  /**
   * Rotates an pixmap as per the given rotate code.
   * 0 do not rotate
   * 1 rotate 90 degrees cw
   * 2 rotate 180 degrees cw
   * 3 rotate 270 degrees cw
   * rotatecode must be >=0
   *
   * @author Aleksander Demko
   */
  QPixmap rotatePixmapByCode(short rotatecode, QPixmap &pix);

  /**
   * Uses both detectExifRotate and detectTagRotate to come up with a reasonable default.
   * Will never return -1 (will return 0 instead).
   *
   * @author Aleksander Demko
   */ 
  short detectMultiRotate(const QString &filename, const hydra::FileItemRecord::tags_t &tags);
}

#endif