Arabic Fonts has a set of marks and it can not meet with each other only in nine cases and is explained below:
See that all marks associated with the shadda work well in ccmp property except fathatan and kasratan because it was suffering from a problem in truetype: when we write: fatha followed fatha … first father disappear behind “The second fatha” and will not be: above or underneath
To solve this problem: This marks the encoding in Unicode, and put it in the keyboard, but opentype ended the previous solution
Can adjust these marks in Glyphs App
In this way, relying on the Anchor option in the compilation of these marks and their work?
By ‘reset anchors’, do you mean the Reset Anchors command (Cmd-Opt-U) in the Glyph menu (Layers menu in Glyphs 1.x)? You can select all 63 glyphs and press Cmd-Opt-U, and all anchors are reset for all glyphs at once.
If the anchors are already there, you will likely not have to change them, or not much, when you change the mark.
With "points", you mean the anchors? You can use my script Anchor Mover 2 to batch process all anchor positions. E.g., if you need to move all "_top" anchors up by 10 units, you select the diacritics, run the script, and choose the appropriate settings in the Anchor Mover window.
Anchor positions are also interpolated, just make sure they are all there in all weights. In Glyphs 2, a glyph is marked as incompatible if the anchors are not in sync between all masters.