#include <npic.h>

void my_draw (Npic_image *np2, Npic_image *np1, double c1, double c2)
{
    if (NpicImageIsOK_DS1 (np2, np1, __func__) != NPIC_SUCCESS)
        return;
        
    if (NpicSameImage (np2, np1, NPIC_TYPE | NPIC_SIZE) != NPIC_SUCCESS) {
        np2->gen.ok = NpicError (__func__, NPIC_ERR_INCOMPAT, ""); 
        return; 
    }
        
    switch (np2->type) {
    
        case NPIC_IMAGE_2L : {
            Npic_image_2l *p2 = NpicCastImage (np2),
                          *p1 = NpicCastImage (np1); 
            int x, y;
        
            for (y = 0; y < p2->ymax; y++)
            for (x = 0; x < p2->xmax; x++)
                p2->pix[y][x] = p1->pix[y][x]*c1 + c2;
        
            return;
        } 
                
        case NPIC_IMAGE_3L : {
            Npic_image_3l *p2 = NpicCastImage (np2),
                          *p1 = NpicCastImage (np1); 
            int x, y, z;
        
            for (z = 0; z < p2->zmax; z++)
            for (y = 0; y < p2->ymax; y++)
            for (x = 0; x < p2->xmax; x++)
                p2->pix[z][y][x] = p1->pix[z][y][x]*c1 + c2;
        
            return;
        } 
        
        default : 
            np2->gen.ok = NpicError (__func__, NPIC_ERR_UNEX_NPIC, "");
    }
} 

int main ()
{
    Npic_image *np1, *np2;
    Npic_image_2l *p1;
    int x, y;

    /* Create a 2L image = 2D image with signed long pixels (4 bytes). height 
       is ymax=12, width is xmax=20, external borders are ybor=0, xbor=0. */
    np1 = NpicCreateImage_2l (12, 20, 0, 0);
    if (np1 == NULL) exit (1);
    
    /* Assign values to pixels */
    p1 = NpicCastImage (np1);
    for (y = 0; y < p1->ymax; y++)
    for (x = 0; x < p1->xmax; x++)
        p1->pix[y][x] = (x + y) % 16;
  
    /* Create a second image with same size and type than np1 */
    np2 = NpicDupImage (np1);
    if (np2 == NULL) exit (1);

    /* Compute np2 pixels values */
    my_draw (np2, np1, 2, 4);
  
    /* Print image */
    NpicPrintImage (np2);
    
    /* Destroy image */
    NpicDestroyImage (np1);
    NpicDestroyImage (np2);
    exit(0);
}