Accelerators work with additional keys

I am affected, and think this is linked to https://bugs.launchpad.net/sakura/+bug/1673068

actually, I'm not affected, I just proofread my sakura.conf with the
cheat sheet I posted in https://bugs.launchpad.net/sakura/+bug/689572
And every thing looks in order now.

I think this is caused by checking if the modifier key is pressed, instead of checking if *only* that modifier key is pressed.

Based on https://developer.gnome.org/gdk3/stable/gdk3-Windows.html#GdkModifierType, we can't check if they match exactly, we have to mask out reserved masks, which we do using GDK_MODIFIER_MASK.

The attached patch should do this. It also lets me set

copy_accelerator=4

and have
Ctrl+C = copy
Ctrl+Shift+C = interrupt

Hmm, that doesn't work if e.g. Num Lock is pressed.

Next thought: try doing gdk_keymap_add_virtual_modifiers then mask out everything except SHIFT, CONTROL, SUPER, HYPER, and META (and maybe LOCK). Hopefully there is already a library for this, or there is a better approach.

Something using gtk_accelerator_get_default_mod_mask seems right.
https://developer.gnome.org/gtk3/stable/checklist-modifiers.html

I fixed this by editing ~/.config/sakura/sakura.conf to change font size with ctrl-shift-minus and ctrl-shift-equals (plus) - at that point ctrl-minus results in the ctrl-underscore key, which is what I wanted:

font_size_accelerator=5
increase_font_size_key=plus
decrease_font_size_key=minus