Cairo/Pango: compute character widths fast and string widths accurately

This commit has Fl_Cairo_Graphics_Driver compute string widths in 2 ways:
1) when the string contains several unicode characters, the width of the
whole string is computed, accounting for kerning when it occurs;
2) when the string contains a single unicode character, its width is
computed, memorised, and re-used next time it's necessary.

The effect of this approach is
- Fl_Text_Display is fast because it uses memorised single character widths repeatedly
- Fl_Input is drawn accurately because the cursor position is determined
by string widths, not by sums of character widths.

0 files changed, 0 insertions, 0 deletions