Compositing pictures

Compositing is the process of combining two (or more) pictures by placing one over the other. When you add backgrounds, text, and special effects to existing images, you can treat each element as a separate canvas, then composite the individual canvases to create the final picture.

Layering multiple pictures

VizPaint2D's unique layer tool lets you see how your completed composition will look as you work on each individual canvas. With it, you can:

• display two canvases at the same time, in the order that you will be compositing them
• preview the combined result of the images you will be compositing
• modify layers while they are displayed
• instantly see the results of changes you make

Using the alpha channel in compositing

When you place one image over another, the picture on the top must include some transparent areas or the bottom picture will not show through.

You use the alpha channel to control which portions of a picture are visible when composited and which portions are hidden.

You use the paint mode tool to access the alpha channel. For information on using the paint mode tool, see "Choosing paint and display modes" on page 386.