Painting and Drawing

There are two ways to create graphics on a computer: by painting or by drawing. The difference has to do with how the computer thinks of your art. In the case of painting programs, the PalmPilot thinks in one-dot units. To display a “painting” (such as a photo), the PalmPilot must memorize the exact status—black, white, or one of the gray shades—of each pixel (screen dot) on its screen. In other words, it stores a map of your screen. Painting programs, it’s therefore said, generate bitmapped graphics.

When you lay down some “paint,” you turn white pixels some other color. You can erase them, but you can’t change the original shape you painted—a circle, say, or a letter of the alphabet—because the PalmPilot no longer thinks of them as a circle or a letter of the alphabet. On the other hand, you have control over each individual dot.

Drawing programs, on the other hand, create what are called object-oriented graphics (sometimes called vector drawings). When you draw a circle in one of these programs, the PalmPilot doesn’t store it as a map of black dots; instead, it remembers that you drew a circle of a fixed shading and size. In a drawing program, objects remain objects; after you draw a circle, you can return to it later and move it by dragging it. You can overlap another object on top of it—and later change your mind. You can change a circle’s shading long after you drew it.

Both kinds of programs are available on the PalmPilot; here are some of the best. ...

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