Add a preference to zoom only the focused terminal

guake/data/org.guake.gschema.xml

@@ -136,6 +136,11 @@
 		  <summary>Hide tab bar if there is only one tab</summary>
 		  <description>When true, the tab bar will hide when there is only one tab</description>
 		</key>
+        <key name="per-terminal-zoom" type="b">
+            <default>false</default>
+            <summary>Zoom only the focused terminal</summary>
+            <description>When true, the zoom in/out shortcuts change the font size of the focused terminal only, and each terminal keeps its own zoom level. When false, they change the configured font size, zooming every terminal at once.</description>
+        </key>
         <key name="quick-open-enable" type="b">
             <default>false</default>
             <summary>Enable Quick Open feature.</summary>

guake/data/prefs.glade

@@ -2261,6 +2261,23 @@
                                     <property name="top-attach">3</property>
                                   </packing>
                                 </child>
+                                <child>
+                                  <object class="GtkCheckButton" id="per_terminal_zoom">
+                                    <property name="label" translatable="yes">Zoom in/out affects only the focused terminal</property>
+                                    <property name="visible">True</property>
+                                    <property name="can-focus">True</property>
+                                    <property name="receives-default">False</property>
+                                    <property name="tooltip-text" translatable="yes">Each terminal keeps its own zoom level. When disabled, zooming changes the configured font size and every terminal at once.</property>
+                                    <property name="halign">start</property>
+                                    <property name="use-underline">True</property>
+                                    <property name="draw-indicator">True</property>
+                                    <signal name="toggled" handler="on_per_terminal_zoom_toggled" swapped="no"/>
+                                  </object>
+                                  <packing>
+                                    <property name="left-attach">0</property>
+                                    <property name="top-attach">5</property>
+                                  </packing>
+                                </child>
                                 <child>
                                   <object class="GtkBox">
                                     <property name="visible">True</property>

guake/guake_app.py

@@ -950,22 +950,47 @@ def accel_reset_terminal(self, *args):
         HidePrevention(self.window).allow()
         return True
 
+    def zoom(self, step):
+        """Zoom in or out by one step.
+
+        A zoom level is a scale a terminal applies on top of the configured font size.
+        With per-terminal zoom, only the focused terminal is zoomed and each terminal
+        keeps its own level. Otherwise every terminal ends up the same size as the
+        focused one: their individual levels are dropped, and the configured font size
+        is changed instead, so the zoom is remembered across restarts.
+        """
+        notebook = self.get_notebook()
+        terminal = notebook.get_current_terminal()
+
+        if self.settings.general.get_boolean("per-terminal-zoom"):
+            if terminal:
+                terminal.font_scale += step
+            return
+
+        if self.settings.general.get_boolean("use-default-font"):
+            # The font size follows the desktop setting, so there is no configured size
+            # to change here: zoom every terminal to the same level instead.
+            scale = (terminal.font_scale if terminal else 0) + step
+            for term in notebook.iter_terminals():
+                term.font_scale = scale
+            return
+
+        font, _, size = self.settings.styleFont.get_string("style").rpartition(" ")
+        # Start from the size the focused terminal shows, so a terminal zoomed on its
+        # own is the one the others snap to.
+        size = round(int(size) * terminal.font_scale_factor) if terminal else int(size)
+        self.settings.styleFont.set_string("style", f"{font} {max(1, size + step)}")
+        for term in notebook.iter_terminals():
+            term.font_scale = 0
+
     def accel_zoom_in(self, *args):
         """Callback to zoom in."""
-        font = " ".join(self.settings.styleFont.get_string("style").split(" ")[:-1])
-        new_size = int(self.settings.styleFont.get_string("style").split(" ")[-1]) + 1
-        self.settings.styleFont.set_string("style", f"{font} {new_size}")
-        for term in self.get_notebook().iter_terminals():
-            term.set_font_scale(new_size / (new_size - 1))
+        self.zoom(1)
         return True
 
     def accel_zoom_out(self, *args):
         """Callback to zoom out."""
-        font = " ".join(self.settings.styleFont.get_string("style").split(" ")[:-1])
-        new_size = int(self.settings.styleFont.get_string("style").split(" ")[-1]) - 1
-        self.settings.styleFont.set_string("style", f"{font} {new_size}")
-        for term in self.get_notebook().iter_terminals():
-            term.set_font_scale((new_size - 1) / new_size)
+        self.zoom(-1)
         return True
 
     def accel_increase_height(self, *args):

guake/prefs.py

@@ -534,6 +534,10 @@ def on_bold_is_bright_toggled(self, chk):
         """Changes the value of bold_is_bright in dconf"""
         self.settings.styleFont.set_boolean("bold-is-bright", chk.get_active())
 
+    def on_per_terminal_zoom_toggled(self, chk):
+        """Changes the activity of per_terminal_zoom in dconf"""
+        self.settings.general.set_boolean("per-terminal-zoom", chk.get_active())
+
     def on_cell_height_scale_value_changed(self, scale):
         value = scale.get_value()
         self.settings.styleFont.set_double("cell-height-scale", value)
@@ -1290,6 +1294,10 @@ def load_configs(self):
         value = self.settings.styleFont.get_boolean("bold-is-bright")
         self.get_widget("bold_is_bright").set_active(value)
 
+        # zoom only the focused terminal
+        value = self.settings.general.get_boolean("per-terminal-zoom")
+        self.get_widget("per_terminal_zoom").set_active(value)
+
         # cell height scale
         value = self.settings.styleFont.get_double("cell-height-scale")
         self.get_widget("cell_height_scale_adjustment").set_value(value)

guake/terminal.py

@@ -513,8 +513,7 @@ def set_font_scale_index(self, scale_index):
         self.font_scale_index = clamp(scale_index, -6, 12)
 
         font = Pango.FontDescription(self.font.to_string())
-        scale_factor = 2 ** (self.font_scale_index / 6)
-        new_size = int(scale_factor * font.get_size())
+        new_size = int(self.font_scale_factor * font.get_size())
 
         if font.get_size_is_absolute():
             font.set_absolute_size(new_size)
@@ -525,6 +524,11 @@ def set_font_scale_index(self, scale_index):
 
     font_scale = property(fset=set_font_scale_index, fget=lambda self: self.font_scale_index)
 
+    @property
+    def font_scale_factor(self):
+        """Factor the zoom level applies to the configured font size."""
+        return 2 ** (self.font_scale_index / 6)
+
     def increase_font_size(self):
         self.font_scale += 1
 

releasenotes/notes/per_terminal_zoom-102c01144c94d613.yaml

@@ -0,0 +1,17 @@
+release_summary: >
+  Zoom in and out can now apply to the focused terminal only, letting each terminal
+  keep its own zoom level.
+
+features:
+  - |
+      - New "Zoom in/out affects only the focused terminal" preference, in Appearance.
+        When enabled, each terminal keeps its own zoom level, applied on top of the
+        configured font size. When disabled (the default, as before), zooming changes
+        the configured font size and every terminal with it.
+
+fixes:
+  - |
+      - Zooming every terminal no longer applies the new font size twice, once as a
+        font size and once as a terminal font scale, which made a zoom step larger
+        than intended and zoom out a different size than zoom in.
+      - Zooming out repeatedly no longer reaches a font size of zero.