FLASH [#ch,] switch
This command turns on or off flashing in the specified window channel (default #1). Switch can only have the values 0 (to enable flashing) and 1 (to turn flashing on).
This command will only have any effect in MODE 8.
If flashing is enabled, then any characters PRINTed to the given window afterwards will be shown to flash - it is first written out as normal, but then the parts of the character which would normally be shown in the current INK colour will alternate with the colour of the background.
The colour of the background can in fact be different for each row of pixels - this is calculated by the colour of the left-most pixel on each row for each character PRINTed.
This short listing shows the effect of the FLASH command - note that the display is not actually changed back to its original form.
100 PAPER 2: INK 1 120 CSIZE 3,1: MODE 8: CLS 130 FOR i=0 TO 50: LINE 80+i,80 TO 15+i,10 140 INK 7: CURSOR 100,120 150 OVER 1: FLASH 1: PRINT 'This is flashing' 160 CSIZE 1,0: FLASH 0
This command only affects characters PRINTed to the screen after the FLASH 1. There is no effect on graphics commands, or BLOCK or LINE.
Spurious results may occur if you write over part of a flashing character (with OVER -1).
This command does not work on the Amiga-QDOS Emulator or ST/QL Emulators.