获取BMP文件的像素值

Question

获取BMP文件的像素值

我有一个关于读取bmp图像的问题.如何获取bmp图像中的像素值(R,G,B值)？任何人都可以帮我使用C编程语言吗？

Answer 1

注意:如果您的BMP具有Alpha通道,则可能需要为alpha值获取额外的字节.在那种情况下,图像将是image[pixelcount][4],并且您将添加另一getc(streamIn)行来保存第四个索引.我的BMP结果证明不需要那样做.

 // super-simplified BMP read algorithm to pull out RGB data
 // read image for coloring scheme
 int image[1024][3]; // first number here is 1024 pixels in my image, 3 is for RGB values
 FILE *streamIn;
 streamIn = fopen("./mybitmap.bmp", "r");
 if (streamIn == (FILE *)0){
   printf("File opening error ocurred. Exiting program.\n");
   exit(0);
 }

 int byte;
 int count = 0;
 for(i=0;i<54;i++) byte = getc(streamIn);  // strip out BMP header

 for(i=0;i<1024;i++){    // foreach pixel
    image[i][2] = getc(streamIn);  // use BMP 24bit with no alpha channel
    image[i][1] = getc(streamIn);  // BMP uses BGR but we want RGB, grab byte-by-byte
    image[i][0] = getc(streamIn);  // reverse-order array indexing fixes RGB issue...
    printf("pixel %d : [%d,%d,%d]\n",i+1,image[i][0],image[i][1],image[i][2]);
 }

 fclose(streamIn);

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