Atari ST series Technical Reference Manual page 153

Table 7-2. Input Values for Filled Rectangle Function (continued)
Offset Name
WMODE
XI
Yl
X2
Y2
PATPTR
PATMSK
MFILL
CLIP
XMINCL
YMINCL
XMAXCL
YMAXCL
These inputs are the same for Horizontal Line, with the
addition of the clipping rectangle variables. XMINCL,
YMINCL, XMAXCL, and YMAXCL are used to designate the
borders of the clipping rectangle. The CLIP variable is used
to indicate whether the clipping actually takes place. If CLIP
is set to 0, clipping is turned off, and the rectangle desig­
nated by the other four variables is ignored. If CLIP is not 0,
clipping is turned on, and only the portion of the filled rec­
tangle that lies within the clipping rectangle will be drawn.
A similar call to Filled Rectangle is Filled Polygon
($A006). Instead of drawing a filled box, this call draws a
filled shape with an arbitrary number of sides. It does this by
drawing a series of filled horizontal lines of unequal size.
The input values used by Filled Polygon are shown in Table
7-3.
Table 7-3. Input Values Used by Filled Polygon
Offset Name
CONTRL
PTSIN
COLBITO
COLBIT1
COLBIT2
Line A Routines
Offset
Writing mode
$24
$26 Starting x coordinate
Starting y coordinate
$28
Ending x coordinate
$2A
Ending y coordinate
$2C
$2E Pointer to fill pattern array
Pattern index (length - 1)
$32
$34 Multi-color fill pattern flag (zero = single
plane, nonzero = multiplane)
Clipping flag (zero = off, nonzero = on)
$36
Coordinate of left side of clip rectangle
$38
$3A Coordinate of top of clip rectangle
Coordinate of right side of clip rectangle
$3C
Coordinate of bottom of clip rectangle
$3E
Offset
Pointer to a word array. The second
$04
member of the array, CONTRL[l], contains
the number of polygon vertices
Pointer to a word array. This array
$0C
contains polygon vertex pairs in the format
(xl, yl), (x2, y2), and so on.
Bit value for color plane 0
$18
$1A Bit value for color plane 1
$1C Bit value for color plane 2
Description
Description
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