Edit-json: add kerning filter (#3499)

* edit-json: add kerning filter
* fix missing kerning pairs

3 files changed, 80 insertions, 5 deletions

diff --git a/lib/gui/edit_json/combo_prompt.py b/lib/gui/edit_json/combo_prompt.py
new file mode 100644
index 00000000..bebb1947
--- /dev/null
+++ b/lib/gui/edit_json/combo_prompt.py
@@ -0,0 +1,49 @@
+import wx
+
+
+class PromptingComboBox(wx.ComboBox):
+    def __init__(self, parent, choices=[], style=0, **kwargs):
+        if choices is None:
+            choices = []
+        wx.ComboBox.__init__(self, parent, wx.ID_ANY, style=style, choices=choices, **kwargs)
+        self.choices = choices
+        self.Bind(wx.EVT_KEY_DOWN, self.on_button_down)
+        self.Bind(wx.EVT_TEXT, self.on_text_edit)
+        self.Bind(wx.EVT_TEXT_ENTER, self.on_text_edit)
+        self.ignore_text_event = False
+        self.delete_key = False
+        self.found_choice = False
+        self.parent = parent
+
+    def update_choices(self, choices):
+        self.choices = choices
+
+    def on_button_down(self, event):
+        if event.GetKeyCode() == 8:
+            self.delete_key = True
+        event.Skip()
+
+    def on_text_edit(self, event):
+        current_text = event.GetString()
+        if len(current_text) == 0 or current_text == " ":
+            self.delete_key = False
+            self.parent.on_combobox_change(event)
+            return
+        if self.ignore_text_event:
+            self.ignore_text_event = False
+            return
+        if self.delete_key:
+            self.delete_key = False
+            if self.found_choice:
+                current_text = current_text[:-1]
+
+        self.found_choice = False
+        for i, choice in enumerate(self.choices):
+            if choice.startswith(current_text.strip()):
+                self.ignore_text_event = True
+                self.SetValue(choice)
+                self.SetInsertionPoint(len(current_text))
+                self.SetTextSelection(len(current_text), len(choice))
+                self.found_choice = True
+                self.parent.on_combobox_change(event)
+                break
diff --git a/lib/gui/edit_json/main_panel.py b/lib/gui/edit_json/main_panel.py
index 8b896629..895baef4 100644
--- a/lib/gui/edit_json/main_panel.py
+++ b/lib/gui/edit_json/main_panel.py
@@ -1,6 +1,6 @@
 # Authors: see git history
 #
-# Copyright (c) 2023 Authors
+# Copyright (c) 2025 Authors
 # Licensed under the GNU GPL version 3.0 or later.  See the file LICENSE for details.
 
 import json
@@ -41,7 +41,7 @@ class LetteringEditJsonPanel(wx.Panel):
         self.font = None
         self.default_variant = None
         self.font_meta = defaultdict(list)
-        self.glyphs = None
+        self.glyphs = []
         self.kerning_pairs = None
         self.kerning_combinations = []
         self.horiz_adv_x = {}
@@ -240,14 +240,17 @@ class LetteringEditJsonPanel(wx.Panel):
         self.horiz_adv_x = self.font.horiz_adv_x
 
         kerning_combinations = combinations_with_replacement(self.glyphs, 2)
-        self.kerning_combinations = [' '.join(combination) for combination in kerning_combinations]
-        self.kerning_combinations.extend([f'{combination[1]} {combination[0]}' for combination in kerning_combinations])
+        self.kerning_combinations = []
+        for combination in kerning_combinations:
+            self.kerning_combinations.append(f'{combination[0]} {combination[1]}')
+            self.kerning_combinations.append(f'{combination[1]} {combination[0]}')
         self.kerning_combinations = list(set(self.kerning_combinations))
         self.kerning_combinations.sort()
 
         self.update_legacy_kerning_pairs()
         self.update_settings()
         self.update_kerning_list()
+        self.update_filter_list()
         self.update_glyph_list()
         self.update_preview()
 
@@ -314,7 +317,14 @@ class LetteringEditJsonPanel(wx.Panel):
             self.settings_panel.font_kerning.horiz_adv_x_default.SetValue(self.font.horiz_adv_x_default)
         self.settings_panel.font_kerning.horiz_adv_x_space.SetValue(self.font.word_spacing)
 
-    def update_kerning_list(self):
+    def update_filter_list(self):
+        # Update filter list
+        self.settings_panel.kerning_filter.Clear()
+        choices = [' '] + self.glyphs
+        self.settings_panel.kerning_filter.AppendItems(choices)
+        self.settings_panel.kerning_filter.update_choices(choices)
+
+    def update_kerning_list(self, filter_value=None):
         kerning_list = self.settings_panel.kerning_list
         # Add the rows
         kerning_list.ClearAll()
@@ -323,6 +333,8 @@ class LetteringEditJsonPanel(wx.Panel):
         kerning_list.AppendColumn("Current kerning", width=wx.LIST_AUTOSIZE_USEHEADER)
         kerning_list.AppendColumn("New kerning", width=wx.LIST_AUTOSIZE_USEHEADER)
         for kerning_pair in self.kerning_combinations:
+            if filter_value is not None and filter_value.strip() not in kerning_pair:
+                continue
             if self.font_meta['text_direction'] == 'rtl':
                 pair = kerning_pair.split()
                 kerning_pair = ' '.join(pair[::-1])
diff --git a/lib/gui/edit_json/settings_panel.py b/lib/gui/edit_json/settings_panel.py
index 8c51a3d0..b4fd51d9 100644
--- a/lib/gui/edit_json/settings_panel.py
+++ b/lib/gui/edit_json/settings_panel.py
@@ -7,6 +7,7 @@ import wx
 
 from ...i18n import _
 from ...lettering.categories import FONT_CATEGORIES
+from .combo_prompt import PromptingComboBox
 from .editable_list import EditableListCtrl
 
 
@@ -56,6 +57,7 @@ class SettingsPanel(wx.Panel):
         kerning_pairs = KerningPairs(self.notebook)
         self.notebook.AddPage(kerning_pairs, _("Kerning pairs"))
         self.kerning_list = kerning_pairs.kerning_list
+        self.kerning_filter = kerning_pairs.filter_kerning
 
         apply_sizer = wx.BoxSizer(wx.HORIZONTAL)
         self.cancel_button = wx.Button(self, label=_("Cancel"))
@@ -285,9 +287,21 @@ class KerningPairs(wx.Panel):
 
         sizer = wx.BoxSizer(wx.VERTICAL)
 
+        choices = [' '] + self.parent.glyphs
+        self.filter_kerning = PromptingComboBox(self, choices=choices, style=wx.TE_PROCESS_ENTER)
+        sizer.Add(self.filter_kerning, 0, wx.EXPAND | wx.TOP | wx.BOTTOM, 5)
+
         self.kerning_list = EditableListCtrl(self, style=wx.LC_REPORT | wx.SUNKEN_BORDER)
         self.kerning_list.Bind(wx.EVT_LIST_ITEM_SELECTED, self.parent.on_kerning_list_select)
         self.kerning_list.Bind(wx.EVT_LIST_END_LABEL_EDIT, self.parent.on_kerning_update)
 
         sizer.Add(self.kerning_list, 1, wx.EXPAND, 0)
         self.SetSizer(sizer)
+
+    def on_combobox_change(self, event):
+        combobox = event.GetEventObject()
+        value = combobox.GetValue().strip()
+        if value and value != " ":
+            self.parent.update_kerning_list(value)
+        else:
+            self.parent.update_kerning_list()