Any ideas on scaled Font smoothing

Peter Jakacki · 2011-08-01 07:15

Hi everyone, I know I've been really quiet on the forum lately, haven't really had much of a chance to lurk either :frown:
Anyway, I'm not sure if I'm reinventing the wheel here but I wanted scaled VGA characters so I got stuck into some PASM tonight and although I'm really rusty I managed to get the basics of scaling the Prop font onto a VGA monitor. So far so good....

What I'd like to do is smooth the font especially when it's scaled up. Any ideas (any code) anyone?

Cheers,
Peter

Ale · 2011-08-01 07:28

It just occurred to me that using a line algorithm between the "points" could do... but maybe just adding a triangle-shaped filling character may do:

 0
00

would be filled to

/0
00

a small scanning algorithm could do these fillings

Peter Jakacki · 2011-08-01 17:56

Hi Ale,

I'm looking at a pixel by pixel smoothing during rendering as this is a bit-mapped display and I am drawing the scaled characters straight from the Prop's ROM. I was thinking of an algorithm that worked a bit like molasses in that the stickiness of it would be determined by the scaling factor. You with me so far??? A bit like we smooth out waveforms with capacitors.

If there is a lookahead to what the next non-repeat row of pixels are then we can (depending upon the scaling factor of course) make gradual adjustments in each repeat row of the old data.

Take is un-smoothed sample for instance:

****
        ****
        ****
        ****
    ********
    ********
    ********
    ********
    ****
    ****
    ****
    ****
    ********
    ********
    ********
    ********


Adding pixels (#) and subtracting pixels (.) to approach the next non-repeat row (every 4th here) will smooth out the shape.

        ****
       #****
      ##****
     ###****
    ********
    *******.
    ******..
    *****...
    ****
    ****#
    ****##
    ****###
    ********
    ********
    ********
    ********

So we end up with:

        ****
       *****
      ******
     *******
    ********
    *******
    ******
    *****
    ****
    *****
    ******
    *******
    ********
    ********
    ********
    ********

Okay, I'm probably talking more than doing at the moment but I did ask. I will have to try this out on the same display and compare the difference.

Ale wrote: »
It just occurred to me that using a line algorithm between the "points" could do... but maybe just adding a triangle-shaped filling character may do:
 0
00

would be filled to

/0
00
a small scanning algorithm could do these fillings

Any ideas on scaled Font smoothing

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