Inverted glyph: bitmap > SVG via autotrace > glyph via fontforge

solved this simply by using potrace instead of autotrace.

for reference, these are the steps:

convert bitmap to svg (linux command line):

potrace -s sourceimg.bmp

use svg as glyph (python):

import fontforge
font = fontforge.open('blank.sfd')
glyph = font.createMappedChar('A')
glyph.importOutlines('sourceimg.svg')
font.generate('testfont.ttf')

That's it, result below for use on a website:

css:

@font-face
{
font-family: testfont;
src: url('testfont.ttf');
}

html:

<span style="font-family:testfont; font-weight:normal; color:green;">A</span>
<span style="font-family:testfont; font-weight:bold; color:green;">A</span>