Not overwriting pre-existing powerline glyphs

[Finii]

I just noticed this:

Source

I am working on not overwriting powerline glyphs if they are already present in the font to be patched.

Technically the foundation is there:

            # check if a glyph already exists in this location
            if careful or 'careful' in sym_attr['params']:

careful is the command line option --careful, and the other careful can be specified here for example:

        SYM_ATTR_POWERLINE = {
            'default': {'align': 'c', 'valign': 'c', 'stretch': 'pa', 'params': ''},

            # Arrow tips
            0xe0b0: {'align': 'l', 'valign': 'c', 'stretch': 'xy', 'params': {'overlap': 0.02}},
            0xe0b1: {'align': 'l', 'valign': 'c', 'stretch': 'xy', 'params': {'overlap': 0.02}},

-            0xe0b0: {'align': 'l', 'valign': 'c', 'stretch': 'xy', 'params': {'overlap': 0.02}},
+            0xe0b0: {'align': 'l', 'valign': 'c', 'stretch': 'xy', 'params': {'overlap': 0.02, 'careful': True}},

But then, for this to consistently work, we would need to take our box size from the preexisting glyphs, i.e. self.font_dim. That part is missing. The possible overlap must then also be taken into account.

Is this something we want (to try out at least)?
Shall a PR be created?

I patch Cascadia Code without replacing the Poweline Glyphs since they got them originally, and that is quite ok.
But, as far as I recall, the 'small colored line' (i.e. #29) is already present in Cascadia Code Powerline ;-)

P.S. Maybe rather

             # check if a glyph already exists in this location
-            if careful or 'careful' in sym_attr['params']:
+            if careful or sym_attr['params'].get('careful'):

as this would evaluate the 'careful': False to not be careful :->

Edit: Strikeout one line

[Finii]

Strangeness....

Font in top window is patched with --careful, while the lower one is Cascadia Code PL 'original'.

This is a starting point for investigation of that ugly small line..,.

Edit: Add 'PL' to font name

[Finii]

Hmm, can not reproduce my own font....

fontforge font-patcher --careful --makegroups --complete ~/Downloads/CascadiaCode-2110.31/ttf/static/CascadiaCodePL-Regular.ttf

and the resultant font does not have the small line?

But without --careful it does have the line. Lets examine the differences in that glyph:

Left: Nerd Font E0B0, right: Cascadia Code E0B0 😬

Negative left side bearing to cover up the gap 🎉