Understanding canvases

This is an introduction to CANVAS drawing.

A canvas element defines a drawing area in a form, to show basic colored shapes.

Canvas can draw lines, rectangles, ovals, circles, texts, arcs, and polygons. Keys can be bound to graphical elements for selection with a right or left mouse click.

In programs, you select a given canvas area by name and you create the shapes in the abstract user interface tree by using the built-in DOM API, or helper functions.

The painted canvas is automatically displayed on the front-end when an interactive instruction is executed, such as MENU or INPUT.

Each canvas element is identified by a unique number (id). You can use this identifier to bind mouse clicks to canvas elements.