Circle in Font not completely round when font is used

Rae2J
Rae2J Posts: 1
in Type Design Technique & Theory
Hello there,

i am completely new to Font design. I work in IT and in my free time i am designing and producing adapted products for blind and visually impaired people. My wife is blind, so i have some experience in that field.

There is a Truetype font for wrtiting in Braille. That means i type the text like here and the font creates the dots according to the Braille dots.
I am based in Switzerland, so my native tongue is german and the font i use is the german standard Braille Truetype font.

The problem i am facing now, is that if i write with that font, the dots in the font are not perfectly round. If i want to use them in a 3D Software i face some problems.

So i thought i am a smart guy, and downladed FontForge. installed it, opened the Braille font and saw that the circles where not really exact circles. So i made a test with the letter A and replaced the dot (circle) with a circle i made, holding the shift key while drawing it. So i assume it must be precisely round. I checked it with the position coordinates i saw in Fontforge and it seemed very round. I made a Screenshot and tested it within a Vector Program with an overlayed circle and its completely round.

Then i saved the font and installed it.

When i now use the font in the vector program, the dot (circle) is not a 100% round anymore.
When i overlay it with a perfect round circle i see that there are (very tiny) differences between the font and my circle.

The picture shows the fonts circle in yellow and my reference circle in the back in red. 



I know this is practically no difference, but to my workflow it really IS a big difference.
In other words -  the 3D software still gives me a hard time using the font and much time of work to correct this.

So with no clue where to start i searched the net and found your page here.
And now i am hoping that you guys know whats wrong and how to correct it.

I am not bound to FontForge. If there is a program that does the job, that would be good too.
I only rather fix the font, than to fix every dot manually in the 3D software.

Thank you in advance for your help and your time. I really apreciate it!

Greetings
Reto

Tagged:

Answers

  • Georg Seifert
    Georg Seifert Posts: 688
    Try exporting as CFF based OpenType. You drew the circle using postscript curves and the conversion to TrueType curves will introduce those tiny changes. 
  • John Hudson
    John Hudson Posts: 3,768
    edited September 1
    In addition  to Georg’s suggestion, and in case your workflow requires a TrueType font: increase the font UPM value and scale your outline accordingly. This increases the native resolution of the outline geometry.
    In a CFF font, you also have the option to use fractional coordinates, but in TTF all coordinates are unitised so the higher the UPM the more accurate the geometry.
  • John Savard
    John Savard Posts: 1,243
    It should also be noted that because True Type uses Bezier curves, it is impossible to draw a mathematically exact circle. I believe that's also true for the Adobe alternative that's fallen into disuse. If you need mathematically exact circles - and not a closer approximation, which more points can achieve, you may have to do something different.

Categories