// da completare...
#define IDX(x,y,destWidth) x+y*w

__kernel void shear45(__global char* sourceImage,
                    __global char* destImage,
                    char backColor,
                    int destWidth,
                    int destHeight){

    /* getting coordinates */
    int x = get_global_id(0);
    int y = get_global_id(1);

    if(x > destWidth or y > destHeight) return;

    int h = destHeight;
    int w = destWidth - destHeight;
    destImage[IDX(x,y,destWidth)] = (x < y || x >= w+y) ? gray : in[IDX(x-y, y, w)];
}