About Paths

Paths provide several useful drawing techniques including:

• An alternate means of generating filled or outlined irregular figures and nonrectangular shapes

• An efficient means of producing hollow text in an outline font

• The only means of clipping (restricting the area of interest of a picture) to circular, elliptical, or other nonrectangular figures

• The only means of drawing lines with a thickness that can be transformed

These techniques are respectively illustrated in the following figures:

Drawing Techniques Achieved with Paths

A path is similar to an area, but there are fundamental differences between the two. The following table describes their similarities and contrasts.

┌──────────────────────────────┬──────────────────────────────┐│Paths                         │Areas                         │
├──────────────────────────────┼──────────────────────────────┤
│Functions that define a path  │Functions that define an area │
│are bracketed by GpiBeginPath │are bracketed by GpiBeginArea │
│and GpiEndPath.               │and GpiEndArea.               │
├──────────────────────────────┼──────────────────────────────┤
│Paths are defined in world    │Areas are defined in world    │
│coordinates.                  │coordinates.                  │
├──────────────────────────────┼──────────────────────────────┤
│Paths can be modified before  │Areas are displayed           │
│being displayed or used for   │immediately on completion.    │
│clipping.                     │                              │
├──────────────────────────────┼──────────────────────────────┤
│Paths can be used by          │Areas cannot be used as       │
│applications to perform       │clipping regions.             │
│clipping.                     │                              │
├──────────────────────────────┼──────────────────────────────┤
│Paths can be converted into   │Areas cannot be converted into│
│graphics objects called       │regions.                      │
│regions.                      │                              │
├──────────────────────────────┼──────────────────────────────┤
│Six operations can be         │Only two operations can be    │
│performed on paths, each      │performed on areas (specified │
│requiring a separate function:│with options when creating the│
│                              │area):                        │
│Outline                       │                              │
│Fill                          │Outline                       │
│Modify                        │Fill                          │
│Stroke                        │                              │
│Convert to clip path          │                              │
│Convert to region             │                              │
└──────────────────────────────┴──────────────────────────────┘