[Coco] Saving and Restoring Cursor position in Basic09.
L. Curtis Boyle
curtisboyle at sasktel.net
Mon Jul 6 15:21:32 EDT 2020
Much to my surprise, unfortunately, that call only works with VDG (32x16) screens. I thought that we had put it in for Level II, but apparently not. We plan on rectifying that by the Beta 6 release. Right now, figuring out what to do on a graphics window; as in what to do with 1) 6 bit fonts, 2) proportional fonts. For 1), we can return the pixel position or some way of returning the character X position based on pixel position, but if one has switched font widths in the middle of line, it may not line up properly for either 6 or 8 pixel wide fonts. And proportional is a crap shoot; there is no table of sizes, as it is is calculated on the fly based on pixel data within each character in the font. So setting a flag bit indicating “I am return pixel position, not a text position”, along with a pixel X position, my be smarter that “guessing”. I *think* the original version 3.0 Level II upgrade only supported hardware text screens, so they didn’t have to worry about it. I would like to extend that; just exactly what method is best (closest position to a basic 8x8 cel, so that it returns a “text” position, or the special bit flags+pixel position. Tim, if you have time on Discord, it might be worth a chat.
> On Jul 6, 2020, at 1:10 PM, tim lindner <tlindner at macmess.org> wrote:
> In this document:
>
> https://colorcomputerarchive.com/repo/Documents/Manuals/Operating%20Systems/OS-9%20Level%201%20(Tandy).pdf
>
> At the very end, there is an addendum that talks about the SS.Cursr
> get status call. It will return the X and Y position of the cursor.
>
> I think it only works in true text modes.
>
> To set the cursor position there should be documentation in the main
> manual DISPLAY hex codes that will accomplish that.
>
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