void drawCoordinates(Bmp* this, int resolution, int offset)
{
    drawLine(this,BLACK,offset,offset,this->width-offset,offset);
    drawLine(this,BLACK,offset,offset-1,this->width-offset,offset-1);
    drawLine(this,BLACK,offset,offset-2,this->width-offset,offset-2);
    drawLine(this,BLACK,offset,offset,offset,this->height-offset);
    drawLine(this,BLACK,offset-1,offset,offset-1,this->height-offset);
    drawLine(this,BLACK,offset-2,offset,offset-2,this->height-offset);

    int i;

    for(i=offset+resolution;i<=this->width-offset;i=i+resolution)
    {
        drawLine(this,BLACK,i-1,offset+10,i-1,offset-10);
        drawLine(this,BLACK,i,offset+10,i,offset-10);
        drawLine(this,BLACK,i+1,offset+10,i+1,offset-10);
    }

    for(i=offset+resolution;i<=this->width-offset;i=i+resolution)
    {
        drawLine(this,BLACK,offset+10,i-1,offset-10,i-1);
        drawLine(this,BLACK,offset+10,i,offset-10,i);
        drawLine(this,BLACK,offset+10,i+1,offset-10,i+1);
    }
}