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Forum Index : Microcontroller and PC projects : MMBasic Question
| Author | Message | ||||
| toml_12953 Guru  Joined: 13/02/2015 Location: United StatesPosts: 733 |
I'm using PicoMite MMBasic 7.00RC2. Is it possible to read the screen for a value? I'd like to be able to have the user type a value and press a function key to store that number into a variable. Sort of like a TI-59 or HP-67 does. It would make translating calculator programs so much easier than having INPUT statements. |
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Martin H. Guru Joined: 04/06/2022 Location: GermanyPosts: 1569 |
If I understand you correctly, you want to be able to determine which character is displayed at a given position on the screen. Bad news The Picomite does not have a real “text screen” The image you see is always a graphical screen(like back then, for example, on the ZX Spectrum). Therefore, you cannot simply read from a memory location to retrieve the character displayed at the desired position. Of course, you can write a program or a SUB that emulates such a function by creating an array that, when written to the screen, simultaneously fills a string array with the characters, from which you can later read the value. The downside is (Except that it's a hassle and takes longer) that you lose the pixel-precise placement of the letters, since they must then always be aligned with the grid. Another approach would be to write a basic OCR program in which you first read the bit patterns of all characters (32–127) and then compare those with bit patterns on the screen. Edited 2026-10-19 17:19 by Martin H. 'no comment |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 9217 |
I'd use a Sub. On entry you provide the x and y coordinates for the string clear a local string zero local character position counter z run a loop. take a key via Inkey$ test it if it's a function key return that and the string converted to a number if it's a number print it at x+z,y, add MM.INFO(FONTWIDTH) to z and add it to the local string loop back You could polish this up in several ways. You may want a cancel key for example or self-clearing on exit or a limit on the number of characters. Mick Zilog Inside! nascom.info for Nascom & Gemini |
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| Martin H. Guru Joined: 04/06/2022 Location: GermanyPosts: 1569 |
Tiny OCR (Just an idea) Put simply, it might look something like this Preparations at Start of the the Program DIM REF%(95, 11) ' 96 chars (ASCII 32..127), 12 lines Dim integer c,bits,row,col, BG=0 'Background Color FOR c = 32 TO 127 ' Print a character at a known position, z.B. (0,0) PRINT @(0,0) CHR$(c); ' Read in the 8x12 bit mask and store it in REF% FOR row = 0 TO 11 bits = 0 FOR col = 0 TO 7 IF PIXEL(col, row) <> BG THEN bits = bits OR (1 << col) NEXT col REF%(c-32, row) = bits NEXT row NEXT c character recognition function (untested) FUNCTION RECOGNIZE$(x0, y0) Of course, this only works if all characters are aligned to the fixed grid.local zelle(11) FOR row = 0 TO 11 bits = 0 FOR col = 0 TO 7 IF PIXEL(x0+col, y0+row) <> BG THEN bits = bits OR (1 << col) NEXT col zelle(row) = bits NEXT row FOR c = 32 TO 127 hit = 1 FOR row = 0 TO 11 IF zelle(row) <> REF%(c-32, row) THEN hit = 0 : EXIT FOR NEXT row IF hit THEN RECOGNIZE$ = CHR$(c) : EXIT FUNCTION NEXT c RECOGNIZE$ = "?" ' unknown END FUNCTION Edited 2026-10-19 17:43 by Martin H. 'no comment |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 4389 |
If the user is typing the value just keep track of what they type (in a string variable, most likely). No need to read the screen and very simple code. John |
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twofingers Guru Joined: 02/06/2014 Location: GermanyPosts: 1782 |
Hi toml_12953, another possible solution - the one I use in FM - involves a "shadow array" for the screen (to store characters and colors) combined with a print routine (called "Prat()" in FM) that writes to the screen and the array simultaneously. This approach is highly reliable and fast, and it ensures you always know exactly what is stored at any given position. A prerequisite is that all write operations must follow a fixed grid. Regards Michael |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 9217 |
There are many ways to skin a cat. Especially in MMBasic. :) Mick Zilog Inside! nascom.info for Nascom & Gemini |
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