advanceFactor method
How far this codePoint index is within the glyph.
Implementation
double advanceFactor(int index, bool inv) {
if (index >= indices.length) {
return 0;
}
var glyphIndex = indices[index];
int start = index;
while (start > 0) {
if (indices[start - 1] != glyphIndex) {
break;
}
start--;
}
int end = index;
while (end < indices.length - 1) {
if (indices[end + 1] != glyphIndex) {
break;
}
end++;
}
var f = (index - start) / (end - start + 1);
if (inv) {
return 1.0 - f;
}
return f;
}