Page 100 Table of Contents Index Page 102
Chapters
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30
A, B, C, D, E



CHAPTER 12. GRAPHICS




Figure 12.7: Two possible definitions of horizontal lines. Left figure is X11 definition.

the rectangular slice above the coordinates, since those pixels are the ones whose centers have
the figure immediately above them. This definition makes it simpler to draw rectilinear borders
around rectilinear areas.

12.5 Drawing Functions

Each drawing function takes keyword arguments allowing any drawing option or suboption to
be supplied separately in the call to the function. In some implementations of CLIM, the
drawing functions may ignore drawing options that are irrelevant to that function; in other
implementations, an error may be signalled. See Chapter 10 for a more complete discussion of
the drawing options. An error will be signalled if any drawing function is called on a sheet that
is mute for output.

While the functions in this section are specified to be called on sheets, they can also be called
on streams and mediums.

Implementation note: The drawing functions are all specified as ordinary functions, not as
generic functions. This is intended to ease the task of writing compile-time optimizations that
avoid keyword argument taking, check for such things as constant drawing options, and so forth.
If you need to specialize any of the drawing methods, use define-graphics-method.

Each drawing function comes in two forms, a "structured" version and a "spread" version. The
structured version passes points, whereas the spread version passes coordinates. See Section 2.3
for more information on this.

Any drawing functions may create an output record that corresponds to the figure being drawn.
See Chapter 15 for a complete discussion of output recording. During output recording, none of
these functions capture any arguments that are points, point sequences, coordinate sequences,
or text strings. Line styles, text styles, transformations, and clipping regions may be captured.


Page 100 Table of Contents Index Page 102
Chapters
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30
A, B, C, D, E