Atari Graphics 2 Vs. 0
I have an Atari 1200XL. I have trouble seeing, so I prefer to use the largest size text mode, GRAPHICS 2. Is it possible to use this mode in place of GRAPHICS 0 for entering, editing, and running programs?
First, you should be aware that GRAPHICS 2 interprets text characters differently than GRAPHICS 0. As set up, only uppercase characters are permitted. Lowercase characters, inverse characters, and inverse lowercase characters all appear in distinctly different colors than uppercase text, but still appear as uppercase. The screen editor is set up to work with GRAPHICS 0, which has 40 columns and 24 lines. GRAPHICS 2 has 20 columns and 12 lines. It is possible to use GRAPHICS 2 in place of GRAPHICS 0, in a limited way. Enter this line to see the technique:
GR.2 + 16 : POKE 87, 0
The + 16 disables the text window, and POKE 87,0 fools the Atari into thinking it is in GRAPHICS 0. In this mode you will be able to type lines and even cursor around and make changes. The bottom half of the screen will be invisible, so scrolling will be tricky. Also, the cursor will only be visible when resting on a character. It wouldn't be too hard to write a machine language editor for using large size characters (perhaps with GRAPHICS 7).
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