直接上代码
enum PixelFlip{__NoFlip = 0,__Horizontally,__Vertically,__Diagonally,};enum PixelChannel{__U8 = 1, // 8 bit__U24 = 3, // 8:8:8 bit};void flip(uint8_t *data, int width, int height, PixelFlip state, PixelChannel channel){if( state == PixelFlip::__NoFlip ) {return;}int cx = width / 2;int cy = height / 2;uint8_t *front = NULL;uint8_t *back = NULL;uint8_t d;switch (state) {case PixelFlip::__Horizontally: {for(int i = 0; i < height; i ++) {front = data + (width * i * channel);back = data + (width * (i + 1) * channel - channel);for(int j = 0; j < cx; j ++) {for(int c = 0; c < channel; c ++) {d = front[c];front[c] = back[c];back[c] = d;}front += channel;back -= channel;}}}break;case PixelFlip::__Vertically: {front = data;for(int i = 0; i < cy; i ++) {back = data + (width * (height - i - 1) * channel);for(int j = 0; j < width; j ++) {for(int c = 0; c < channel; c ++) {d = *front;*front = *back;*back = d;front ++;back ++;}}}}break;case PixelFlip::__Diagonally: {front = data;back = data + (width * height * channel - channel);int count = width * height / 2;for(int i = 0; i < count; i ++) {for(int c = 0; c < channel; c ++) {d = front[c];front[c] = back[c];back[c] = d;}front += channel;back -= channel;}}break;default: break;}}
因为现在做的项目图像是单通道和三通道的，所以写的比较复杂
代码其实还可以优化
如果通道数为偶数，可以看下面的例子
typedef unsigned char U8;typedef unsigned char U24;typedef unsigned int U32;void horizontally_u32(uint8_t *data, int width, int height){int cx = width / 2;U32 *u32 = reinterpret_cast<uint32_t *>(data);U32 *front = NULL;U32 *back = NULL;U32 d;for(int i = 0; i < height; i ++) {front = u32 + (width * i);back = u32 + (width * i + width - 1);for(int j = 0; j < cx; j ++) {d = *front;*front = *back;*back = d;front ++;back --;}}}void horizontally_u24(uint8_t *data, int width, int height){const int channel = 3;int cx = width / 2;int offset;U24 *front = NULL;U24 *back = NULL;U24 d;for(int i = 0; i < height; i ++) {offset = width * channel * i;front = data + offset;back = data + (offset + width * channel - channel);for(int j = 0; j < cx; j ++) {for(int c = 0; c < channel; c ++) {d = front[c];front[c] = back[c];back[c] = d;}front += channel;back -= channel;}front += (cx * channel + channel);back += (cx * channel + width * channel);}}void horizontally_u8(uint8_t *data, int width, int height){int cx = width / 2;U8 *front = NULL;U8 *back = NULL;U8 d;for(int i = 0; i < height; i ++) {front = data + (width * i);back = data + (width * i + width - 1);for(int j = 0; j < cx; j ++) {d = *front;*front = *back;*back = d;front ++;back --;}front += cx + 1;back += (cx + width);}}
垂直翻转比较特殊，不管多少通道，代码也可以通用的
对角线翻转就是 水平翻转 + 垂直翻转
