Read .ppm into One Dimensional Arrays For Red Green and Blue Values

[Remync]

I am writing a program to store a ppm into one dimensional arrays in order to manipulate the data. The image that is being read is not correct. The code is as follows:

if (strcmp (str, "P6") == 0)
 {
 fscanf(fp, "%d %d ", &(I->NCols), &(I->NRows));
  printf("\n\n******In the input image:******\n");
 printf("\nColumns=%d and Rows=%d\n", (I->NCols),(I->NRows));
 pixels =(I->NCols)*(I->NRows);
 printf("There are %d pixels\n", pixels);
 fscanf(fp, "%d ", &temp) ;
 printf("%d\n", temp);
 I->R = (int *) malloc(pixels*sizeof(int));
 I->G = (int *) malloc(pixels*sizeof(int));
 I->B = (int *) malloc(pixels*sizeof(int));
 for (row=0; row < I->NRows; row++)
 {
     for (col=0; col < I->NCols; col++)
     {
         (I->R[row*I->NCols+col]) = (unsigned char) (getc(fp));
         (I->G[row*I->NCols+col]) = (unsigned char) (getc(fp));
         (I->B[row*I->NCols+col]) = (unsigned char) (getc(fp));
 
     }
 }
 

I think that the problem lies in this portion of the above code

(I->R[row*I->NCols+col]) = (unsigned char) (getc(fp));
         (I->G[row*I->NCols+col]) = (unsigned char) (getc(fp));
         (I->B[row*I->NCols+col]) = (unsigned char) (getc(fp));
 

I'm not sure if I am using getc correctly. Now, I know that there are easier ways to do this. This method of one dimensional arrays is required by the assignment however. Essentially, there is a struct with items red, green and blue. Each of these is a pointer to a one dimensional array which contains only the red, green or blue values in the image. Anyway, let me know if I need to clarify and I thank anyone who can help in advance.

remync

[Flugeldorph]

remync ,

Give more details on the structure of 'I' I can probably help.

Larry

[manontheedge]

In your loop you have to adjust the COLUMN value, the value from the header, that you have in your variable is the number of PIXELS ... there are 3 values per pixel, so you have to multiply the column by 3 to properly get the data.