Table of Contents
Advertisement
CLIP bit = 1
(0, 0)
CLIP bit = 0
System clipping area
Designated user clipping area
(359,239)
Figure 4-13
Example of Clipping Specification
Transparency Specification (TRNS): When color expansion of binary source data is
performed, transparency or non-transparency can be selected on an individual drawing command
basis with the TRNS bit. When transparency is selected, a 0 in the binary source data is
transparent and a 1 has the value of the COLOR1 parameter. When non-transparency is selected, a
binary data 0 has the value of the COLOR0 parameter, and a 1 has the value of the COLOR1
parameter. With multi-valued source data, "all-0" data becomes a transparent color, and those pixels
are not drawn. The transparency specification can be used with the POLYGON4A, POLYGON4B,
PLINE, and RPLINE commands; it is invalid for other commands.
Source Style Specification (STYL): When drawing a rectangle, the STYL bit can be used
to select, on an individual drawing command basis, whether the source data is to be enlarged or
reduced, or referenced repeatedly. If no style specification is made, the source data is enlarged or
reduced in proportion to the size of the rendering area. When a style specification is made, the
source data is referenced repeatedly in proportion to the size of the rendering area. This attribute is
therefore used when drawing repeated patterns such as hatch patterns. The source style specification
can be used with the POLYGON4A, and POLYGON4B commands; it is invalid for other
commands.
An example of a source style specification is shown in figure 4-14.
72
Advertisement
Table of Contents
