Inside Macintosh: QuickDraw GX Graphics /

Chapter 5 - Bitmap Shapes / Applying Functions Described Elsewhere to Bitmap Shapes

Functions That Post Errors or Warnings When Applied to Bitmap Shapes

Some QuickDraw GX functions that operate on other types of shapes only post an error or a warning if you try to apply them to a bitmap shape.

For example, the shape-editing functions listed in Table 5-1 operate on the geometric shape types, but not on bitmap shapes. These functions are described in Chapter 2, "Geometric Shapes,"

Shape-editing functions that post errors or warnings when applied to bitmaps

Function name	Error or warning posted
GXGetShapeParts	shape_operator_may_not_be_a_bitmap
GXSetShapeParts	shape_operator_may_not_be_a_bitmap

in this book.

Although you cannot apply the functions listed in Table 5-1 to a bitmap shape, you can use the GXGetBitmapParts and GXSetBitmapParts functions to edit sections of a bitmap. These functions are described in "Editing Bitmaps" beginning on page 5-71.

There are also a number of geometric operations that you cannot apply to bitmap shapes. Table 5-2 lists these functions, which are described in Chapter 4, "Geometric Operations,"

Geometric operations that post errors or warnings when applied to bitmaps

Function name	Error or warning posted
GXBreakShape	graphic_type_does_not_contain_points
GXContainsShape	shape_operator_may_not_be_a_bitmap
GXDifferenceShape	shape_operator_may_not_be_a_bitmap
GXExcludeShape	shape_operator_may_not_be_a_bitmap
GXGetShapeCenter	illegal_type_for_shape
GXGetShapeDirection	graphic_type_does_not_have_multiple_contours
GXGetShapeLength	shape_does_not_have_length
GXInsetShape	graphic_type_cannot_be_inset
GXIntersectShape	shape_operator_may_not_be_a_bitmap
GXInvertShape	shape_cannot_be_inverted
GXReduceShape	graphic_type_cannot_be_reduced
GXReverseDifferenceShape	shape_operator_may_not_be_a_bitmap
GXReverseShape	contour_out_of_range
GXShapeLengthToPoint	shape_does_not_have_length
GXTouchesShape	shape_operator_may_not_be_a_bitmap
GXUnionShape	shape_operator_may_not_be_a_bitmap

in this book.

Most of these geometric operations do not apply to bitmap shapes because the geometry of a bitmap is substantially different from the geometry of a geometric shape.

You can apply a few of the geometric operations to bitmaps, however. These functions are discussed in "Geometric Operations Applicable to Bitmap Shapes" beginning on page 5-58.

Main | Page One | What's New | Apple Computer, Inc. | Find It | Contact Us | Help