Editing QuickDraw GX (section)

====Shape types====
GX shapes could be of various types:
* a straight line defined by its end points.
* a rectangle defined by its left, right, upper and lower bounds.
* a polygon defined by a sequence of vertex coordinates.
* a ''curve'' shape was a single quadratic [[Bézier curve]] defined by three control points.
* a ''path'' shape which was a sequence of quadratic [[Bézier curve]]s. Each control point had an associated flag indicating whether it was "on-curve" or "off-curve". An on-curve point was a Bézier endpoint, while an off-curve point was a Bézier midpoint. If two successive off-curve points were encountered, then an implicit on-curve point was assumed to lie halfway between them. Two successive on-curve points defined a straight-line segment.
* a ''bitmap'' shape contained raster data in any of the supported pixel formats.
* a ''picture'' shape was a grouping of other shapes (possibly including recursive picture shapes), with the option of specifying additional transformations applying to the whole group.
* the various types of ''typographic'' shapes are described in the GX Typography section below.
* additional types which were perhaps not directly useful for drawing, but could be combined with other shapes in geometry calculations: the ''empty'' shape (drawing of which did nothing); the ''point'' shape consisting of a single point; and the ''full'' shape (of infinite extent).