An alternative technique for positioning and moving things on screen is to change the screen coordinate system. For example, you can move a shape 50 pixels to the right, or you can move the location of coordinate (0,0) 50 pixels to the right—the visual result on screen is the same.
By modifying the default coordinate system, we can create different transformations including translation, rotation, and scaling.
Working with transformations can be tricky, but the
translate() function is the most straightforward, so we’ll start with that. As Figure 6-1 shows, this function can shift the coordinate system left, right, up, and down.