ขั้นตอนการเขียนโค้ด · ออฟเซ็ตแถว RGB24 ที่จัดแนว

def bitmap_row_offset(width, height, row, top_down=False):
    if any(type(v) is not int for v in (width, height, row)) or type(top_down) is not bool:
        raise ValueError("bitmap.type")
    if not 1 <= width <= 4096 or not 1 <= height <= 4096 or not 0 <= row < height:
        raise ValueError("bitmap.range")
    stride = ((3*width+3)//4)*4
    physical_row = row if top_down else height-1-row
    return physical_row*stride, stride