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GSX-86: Graphics for the
APe
Input
Output
contr1(I)
contr1(2)
contr1(4)
contr1(6)
contr1(7)
contr1(8)
contr1(9)
intin( I)
ptsin(l)
ptsin(2)
ptsin(3)
ptsin( 4)
contr1(3)
Opcode
=
10
2
Length of color index array
Length of each row in color index array
Number of elements used in each row of
color index array
Number of rows in color index array
Pixel operation to be performed
I -- Replace
2 -- Overstrike
3 -- Complement (xor)
4 -- Erase
Color index array (stored one row at time)
X-coordinate oflower left corner in device
units
Y -coordinate oflower left corner in device
units
X -coordina te of upper righ t corner in device
units
Y -coordina te of upper right corner in device
units
o
GENERALIZED DRAWING PRIMITIVE (GDP)
The Generalized Drawing Primitive (GDP) operation allows you to take advantage
of the intrinsic dra wing ca pabili ties of your graphics device. Special elements such as
arcs and circles can be accessed through this mechanism. Several primitive identifi-
ers are predefined and others are available for expansion.
The control and data arrays are dependent on the nature of the primitive.
In some GDPs (Are, Circle, Pie Slice) redundant but consistent information is
provided. Use only the necessary information for a particular device. Note that all
angle specifications assume that 0 degrees is 90 degrees to the right of vertical, with
values increasing in the counterclockwise direction.
9-27
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