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Work Specification (WORK): When drawing is performed at rendering coordinates with
POLYGON4 commands, the WORK bit can be used to select, on an individual drawing command
basis, whether or not binary work data is to be referenced.
When binary work data referencing is selected, drawing is performed if the work data for the pixel
corresponding to the rendering coordinates is 1, but not if the work data is 0. Drawing can thus be
performed at the rendering coordinates in the same form as the figure drawn at the work
coordinates. Drawing at work coordinates can be performed by either of two methods: drawing by
means of the FTRAP command or drawing by the SuperH. Work coordinates should be drawn so
that there is no collision between drawing by command and drawing by the SuperH.
With the PLINE and RPLINE commands, this attribute is specified but work references are not
performed. The commands that can be used are POLYGON4A, POLYGON4B, and POLYGON4C;
with other commands, the work specification bit should be cleared to 0.
Clipping Specification (CLIP): The Q2 can perform clipping area management. There are
two kinds of clipping area: a system clipping area designated by the SCLIP command, and a user
clipping area designated by the UCLIP command.
The system clipping area is a rectangular area for prescribing a valid drawing range as the display
range when the Q2 performs double-buffering control. Thus the system clipping area is used to
prohibit drawing outside the area. The system clipping area is valid when the CLIP bit is cleared to
0.
The user clipping area is valid when the CLIP bit is set to 1. When the user clipping area is made
valid, the system clipping area becomes invalid. Thus, to prohibit drawing outside the system
clipping area, ensure that the user clipping area fits inside the system clipping area.
In both the system clipping area and the user clipping area, drawing points are drawn even when on
the clipping area boundary.
An example of a clipping specification is shown in figure 4-13.
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