scale.h

著名的 helix realplayer 基于手机 symbian 系统的 播放器全套源代码

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 * Version: RCSL 1.0/RPSL 1.0 
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#ifndef __SCALE_H__
#define __SCALE_H__   1

/*
 * Internal types of scale algorithms:
 *
 *  SHRINK          dest < src
 *  COPY            dest == src
 *  STRETCH         src < dest < 2 * src
 *  STRETCH2X       dest == 2 * src
 *  STRETCH2XPLUS   dest > 2 * src
 */
#define SHRINK_ID           0
#define COPY_ID             1
#define STRETCH_ID          2
#define STRETCH2X_ID        3
#define STRETCH2XPLUS_ID    4

#define SCALE_FUNCS         5

/*
 * Get type of scale algorithm
 */
#define GET_SCALE_TYPE(dest,src,scale)                      \
    {                                                       \
        scale = 1; /* COPY_ID */                            \
        if (dest != src) {                                  \
            if (dest < src)                                 \
                scale --; /* SHRINK_ID */                   \
            else {                                          \
                scale ++; /* STRETCH_ID */                  \
                if (dest >= 2 * src) {                      \
                    scale ++; /* STRETCH2X_ID */            \
                    if (dest > 2 * src)                     \
                        scale ++; /* STRETCH2XPLUS_ID */    \
                }                                           \
            }                                               \
        }                                                   \
    }

#endif /* __SCALE_H__ */