|Syntax||PAN [#ch,] distance [,area]|
This command is very similar to SCROLL except that this enables you to move a window left and right as opposed to up and down. In its most simple form, PAN allows you to move the specified window (default #1) a given number of pixels sideways. If a positive value for the distance is given, the window will move to the right, whereas a negative distance will move the window to the left. Again, as with SCROLL, the gap left behind from the move will be coloured in the current PAPER colour, and any contents of the window moved off the screen will be lost. The additional parameter allowed by PAN lets you specify an area of the given window to be moved. This can have one of the following values:
|0||This moves the whole window (this is the default).|
|3||This moves the whole of the text cursor line.|
|4||This moves everything on the text cursor line to the right of the cursor (including the character under the cursor).|
A short procedure to scroll a given text message across the screen:
100 DEFine PROCedure SCROLL_TEXT(line$) 110 LOCal l$,loop 120 l$=line$ 130 OPEN #3,scr_448x10a32x246 140 PAPER#3,2:INK#3,0:CSIZE#3,1,0:CLS#3 150 AT #3,0,0:PRINT#3,'INCOMING MESSAGE:' 160 INK#3,7 170 REPeat loop 180 IF LEN(l$)=0:EXIT loop 190 AT #3,0,55:PRINT#3,l$(1) 200 BEEP 100,10 210 IF LEN(l$)<=1:EXIT loop 220 l$=l$(2 TO) 230 AT #3,0,18:PAN #3,-8,4 240 PAUSE 30 250 END REPeat loop 260 END DEFine
In low-resolution mode (8 or 12), the distance will always be rounded down to an even number of pixels.
As with SCROLL, odd values for area and distance allow you to access machine code routines (unless you have a THOR XVI, SMS, or Minerva ROM (v1.63 or v1.64). To access these machine code routines:
- Take the TRAP #3 value for D0 and deduct 27.
- If the figure is less than 27, then take the negative result and add to 128.
For example, PAN 0,115 turns on cursor in #1 (TRAP #3,D0=$E).
This is in fact more useful than SCROLL or CLS as area can be used to pass a parameter to D1, thus allowing you for example, to access IOF.POSR - use PAN #3,n%,40 - to move the file pointer.
On pre MG ROMs, this command may fail if the window is smaller than the cursor.
On SMSQ/E pre v2.88, PAN in MODE 8 could ruin the screen display if an odd parameter was specified, since SMSQ/E tried to move the screen by an odd number of pixels (not supported in MODE 8). Although annoying, this only had small effects.
Also please see SCROLL and PAPER. THORs allow you to use IO_TRAP to access additional system calls. Most system calls can be accessed using Toolkit II in any event. Otherwise, see BTRAP, QTRAP, TTET3 and MTRAP. The QDOS/SMS Reference Manual Section 15 contains full details of the TRAP #3 calls.