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cb1

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2008/09/29 08:37

Re:Unrelated LCD question

By itself - the font table will not be sufficient.

Say you're drawing your 1st 6 pixel wide char @ the upper left of the screen. It will fit - in its entirety - into byte 0 of the external frame buffer. Now you wish to place (6 pixel wide) "char 2" - into the next 6 pixels. (pixels 7-12 of that same, top row)

How do you place the new, 2 left-most pixels of "char 2" into frame buffer byte 0 without spoiling the original? (char 1) Can you do this with a font table?

This is why I described the necessity to R-M-W - for "every" screen transaction. With this method you recover, temporarily store, then logically combine the old/original char with the new "intruder."

My old post covered this...

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jrmymllr

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2008/09/29 11:22

Re:Unrelated LCD question

Ahh, I see what you're referring to. In my application, I'll mainly be writing an entire line at once, so there won't be issues with having to overwrite just part of the line. In those rare cases where I need to rewrite just part of the line, I'll simply design it to work out. In reality however this won't be much of an issue.

Now, on to how I'm using a font table. I wrote a nested loop, which is surprisingly short and simple, that takes in the desired text to be written, and using the font table, writes the pixels out to the display in the annoying format (8 bits horizontal) the SED1330 uses. Annoying for writing text using the most common font table format, anyway. Currently it'll support any font up to 8 pixels high, but it will be easy to expand this to any number of pixels high. I suppose I could post the code for anyone who might find it useful. I have a little work to do on it first, though.

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