Displaying Text and Decimal numbers reflected or backwards.

Frank70

Has anyone been able to display text & decimal numbers reflected on a tv display or monitor?

I am trying to reflect a display, therefore the info on the screen has to be reflected or backwards.
i would appreciate any input on this problem.

Thanks, Frank

StefanL38

hello Frank,

in the Prop-manual page 32 is a description how the characters are defined.
With that it should be possible to turnaround the bitpattern

best regards

Stefan

RinksCustoms

With respects to the Hydra manual, this isn't possible with the internal ROM font, (or near impossible). However, a bitmapped "reverse" font is very possible and would be easy to implement, providing you have the memory for a bitmapped font. The ROM font uses an equivalent of the total main memory, 16,384 KB (calculated). You could use less space than that if you omit all the special characters like schematic symbols, special language characters, and any other non-needed characters.

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E³ = Thought

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tpw_man

You MIGHT be able to modify the TV driver to read from right to left so anything you do using the default TV driver will show a mirrored image.

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I am 1011, so be surprised!


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Paul Baker

It is possible but it will require modification to the assembly driver. When the long is loaded frrom the character map you perform a REV on the data which will flip it. You will also have to modify the color table to redistinguish the character. The character map is interleaved (refer to the manual which does a good job explaining this) and they are teased apart into the individual·character through the color map. If the color map were left as it is a chronological steping through the character map whose values are REVed would produce BADCFE instead of the desired ABCDEF. The color map should have the 4 colors in each color entry (LONG)·reversed (0,1,2,3 to 3,2,1,0).

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Paul Baker
Propeller Applications Engineer

Parallax, Inc.

Post Edited (Paul Baker (Parallax)) : 9/29/2008 12:06:57 AM GMT

Rayman

Well, I'm planning on rotating the ROM font 90 degrees for a project...

Haven't actually done it yet...

But, the plan is to copy the ROM font into HUB RAM and then bitwise manipulate it to be rotated.

Then, it's pretty easy to change the base address that the display routines use from that ROM font to the RAM one.

Backwards is even easier because the two tiles used by a character are the same...

As RinksCustoms points out, I would only do the first half of the font to save space...

One trick to keep in mind is that the new font probably has to be 16 long aligned, but I do this all the time for custom graphics tiles...

Post Edited (Rayman) : 9/29/2008 2:07:40 AM GMT

Frank70

Thanks for all the ideas. I will try them sometime this week when I get a chance.
Tanks again to all.

Rayman

Actually, now that I think about your particular question... Paul's idea of inserting a REV instruction in the driver and reversing the colors would save a ton of memory...

Paul Baker

I've thought about my advice and I think that the color mapping should be from 0,1,2,3 to 0,2,1,3 since a bit reversal (00->00, 01->10, 10->01, 11->11) instead of flipping all of the color values.

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Paul Baker
Propeller Applications Engineer

Parallax, Inc.