VDU Variables
Programmer's Reference Manuals
» VDU Variables
VDU Variables
| # | Hex # | Name | Meaning | Co-ordinates 4 |
|---|---|---|---|---|
| 0-127 | &0-&7F | See Mode Variable Numbers | ||
| 128 | &80 | GWLCol | Graphics Window – Lefthand Column | (ic) |
| 129 | &81 | GWBRow | Graphics Window – Bottom Row | (ic) |
| 130 | &82 | GWRCol | Graphics Window – Righthand Column | (ic) |
| 131 | &83 | GWTRow | Graphics Window – Top Row | (ic) |
| 132 | &84 | TWLCol | Text Window – Lefthand Column | |
| 133 | &85 | TWBRow | Text Window – Bottom Row | |
| 134 | &86 | TWRCol | Text Window – Righthand Column | |
| 135 | &87 | TWTRow | Text Window – Top Row | |
| 136 | &88 | OrgX | X coord of graphics Origin | (ec) |
| 137 | &89 | OrgY | Y coord of graphics Origin | (ec) |
| 138 | &8A | GCsX | Graphics Cursor X coord | (ec) |
| 139 | &8B | GCsY | Graphics Cursor Y coord | (ec) |
| 140 | &8C | OlderCsX | Oldest gr. Cursor X coord | (ic) |
| 141 | &8D | OlderCsY | Oldest gr. Cursor Y coord | (ic) |
| 142 | &8E | OldCsX | Previous gr. Cursor X coord | (ic) |
| 143 | &8F | OldCsY | Previous gr. Cursor Y coord | (ic) |
| 144 | &90 | GCsIX | Graphics Cursor X coord | (ic) |
| 145 | &91 | GCsIY | Graphics Cursor Y coord | (ic) |
| 146 | &92 | NewPtX | New point X coord | (ic) |
| 147 | &93 | NewPtY | New point Y coord | (ic) |
| 148 | &94 | ScreenStart | As used by VDU drivers | |
| 149 | &95 | DisplayStart | As used by display hardware | |
| 150 | &96 | TotalScreenSize | Memory allocated to screen | |
| 151 | &97 | GPLFMD | GCOL action for foreground col | |
| 152 | &98 | GPLBMD | GCOL action for background col | |
| 153 | &99 | GFCOL | Graphics foreground col | |
| 154 | &9A | GBCOL | Graphics background col | |
| 155 | &9B | TForeCol | Text foreground col | |
| 156 | &9C | TBackCol | Text background col | |
| 157 | &9D | GFTint | Graphics foreground tint | |
| 158 | &9E | GBTint | Graphics background tint | |
| 159 | &9F | TFTint | Text foreground tint | |
| 160 | &A0 | TBTint | Text background tint | |
| 161 | &A1 | MaxMode | Highest built-in numbered mode known to kernel | |
| 162 | &A2 | GCharSizeX | X size of VDU5 chars (pixels) | |
| 163 | &A3 | GCharSizeY | Y size of VDU5 chars (pixels) | |
| 164 | &A4 | GCharSpaceX | X spacing of VDU5 chars (pixels) | |
| 165 | &A5 | GCharSpaceY | Y spacing of VDU5 chars (pixels) | |
| 166 | &A6 | HLineAddr | Address of horizontal line-draw routine | |
| 167 | &A7 | TCharSizeX | X size of VDU4 chars (pixels) | |
| 168 | &A8 | TCharSizeY | Y size of VDU4 chars (pixels) | |
| 169 | &A9 | TCharSpaceX | X spacing of VDU4 chars (pixels) | |
| 170 | &AA | TCharSpaceY | Y spacing of VDU4 chars (pixels) | |
| 171 | &AB | GcolOraEorAddr | Addr of colour blocks for current GCOLs | |
| 172 | &AC | VIDCClockSpeed | VIDC clock speed in kHz3 | |
| 174 | &AE | Left border size1 | ||
| 175 | &AF | Bottom border size1 | ||
| 176 | &B0 | Right border size1 | ||
| 177 | &B1 | Top border size1 | ||
| 192 | &C0 | Current GraphicsV driver number2 | ||
| 256 | &100 | WindowWidth | Width of text window in chars | |
| 257 | &101 | WindowHeight | Height of text window in chars |
Notes
Unlike the Mode Variables, many of the VDU variables represent changeable properties of the video system.
1 Available from RISC OS 5.07 onwards
2 Available from RISC OS 5.21 onwards. Also available in RISC OS Select, for the current VideoV driver number.
3 Introduced in RISC OS 3, removed in RISC OS 5
4 (ic) indicates values which are stored in internal coordinates: 0,0 is the top-left pixel of the screen, with positive X pointing right and positive Y pointing down.
(ec) indicates values which are stored in external coordinates, i.e. OS units. Positive X points right, and positive Y points up. Most external coordinates are relative to the graphics origin, except the graphics origin itself (variables 136 and 137), which is a coordinate relative to the bottom-left pixel of the screen. The XEig and YEig mode variables can be used to apply the scale conversion between OS units and pixels.
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