Atari ST series Technical Reference Manual page 156

same as the hardware color registers numbers. The corre­
spondence between the two is shown in Table 7-5.
Table 7-5. Correspondence Between Hardware Color Registers and
VDI Color Indices
Color Color
Index
Register
0 0
1 15*
2 1
2
3
4 4
5 6
6 3
7 5
8 7
9
8
10
9
11 10
12 12
14
13
14 11
15 13
* Color register 3 in medium resolution (4-color) mode
The fill pattern and writing mode used for fill are deter­
mined by the same variables as the other line A fill routines.
The color of the filled object is not specified by the COLBIT
variables, however. The fill color is taken from the current
VDI virtual screen workstation. If you haven't opened a VDI
workstation, however, you can still use the Seed Fill function
by creating a dummy virtual workstation variable table. This
is just an array of 16 words, the last of which contains the
VDI color index of the fill color. A pointer to this array must
be stored in the CUR__WORK variable.
There are two final points to note about the Seed Fill
routine. This routine always evaluates the XMINCL,
YMINCL, XMAXCL and YMAXCL variables, whether or not
you've set CLIP on. Therefore, make sure your clipping rec­
tangle is set correctly before making this call. Secondly, this
function calls a user-defined subroutine after each horizontal
line has been filled. Since a complex fill can be a lengthy pro­
cess, this hook was added to allow the programmer to abort
the Seed Fill function before it finishes. If the subroutine re­
148
CHAPTER 7
Default Color
White
Black
Red
Green
Blue
Cyan
Yellow
Magenta
Low White
Gray
Light Red
Light Green
Light Blue
Light Cyan
Light Yellow
Light Magenta