The Glyph Transformer Bold function

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The Glyph Transformer Bold function

Post by William » Sat Nov 17, 2007 6:03 pm

An interesting matter has arisen.

Some readers may have been enjoying the following thread.


Well, this morning I went back to the whiteboard and managed (as I thought at the time) to align a pair of lines for baseline and capitals height guidelines and then drew artwork for seventeen capital letters and two digits for the font, carefully saving print screen images to a series of bmp files.

I then tried to start importing bmp files into FontCreator so as to add the seventeen capitals to the Whiteboard Venetian font.

Yet I found that they were much too large. Investigation found that I had not managed "to align a pair of lines for baseline and capitals height guidelines" but had managed to align a pair of lines for descender and capitals height guidelines.

My first thoughts were that I would need to draw all of the letters again. Upon reflection I wondered if I could adjust the glyphs in the font.

The thing is, FontCreator allows me to scale the whole glyph by a percentage (the figure will need to be about 70%) and allows me to make the lines bold.

I am thinking of doing the bold before the 70% scaling so as to reduce rounding errors.

Looking at the Bold function in the Glyph Transformer I noticed that there are values for horizontal and vertical.

I did a few tests and am thinking that it is worth a try to see if the glyphs can be adjusted, maybe to avoid needing to redraw the artwork, maybe just to play with finding out what happens before needing to redraw the artwork anyway.

So, the Glyph Transformer has values for horizontal and vertical: what happens when going round a curve, like for an O?

So, I tried a test and was delighted and left wondering how it is done by what I found!


Here is a transcript of my notes.

Saturday 17 November 2007.

5:20 pm

Make a copy of the Stardisc font as BOLDTEST.TTF Bold Test.

Copy the disc at 0 to 1 and 2.

Glyph transform the glyph for 1 by 75% horizontal and vertical and the glyph for 2 by 50% horizontal and vertical, in each case about 1024, 1024.

Adjust advance widths to 2048 and the left side bearings and save so that circles centred on (1024, 1024) are produced.

Copy the contour from 2 into 1, reverse its direction.

Copy the whole glyph 1 into 2.

Now, on 2, try Bold 256, 256.

Copy the contour from 0 onto 2 and see whether they align.

Yes, they do.


I am wondering just how complex the algorithm behind that function is!

William Overington

17 November 2007

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