Question

How do you get the pixel data of a bmp image in C?

I can read the structure of the image but is there a way to display the pixel data?

Answer 1

In my opinion, the easiest way of doing it in C, and not C++ is using OpenCV. This library contains a C API that will make your life easier. You can see more details on the documentation, but your code to do a simple task like that would looks like this piece of code:

IplImage* img = 0; 
uchar *data;

// load an image  
img=cvLoadImage("filename.bmp");
if(!img)
{
   printf("Could not load image file: %s\n",argv[1]);
   exit(0);
}

// create a window
cvNamedWindow("mainWin", CV_WINDOW_AUTOSIZE); 
cvMoveWindow("mainWin", 100, 100);

// show the image
while(1)
{
   cvShowImage("mainWin", img );
   if(cvWaitKey(30) > 0)
   break;
}

// release the image
cvReleaseImage(&img);