Add Sixel Support

Related to #1806

sem-ver: feature

Author: theCapypara

guake/data/org.guake.gschema.xml

@@ -171,6 +171,11 @@
             <summary>Audible bell</summary>
             <description>If true, the system alert sound will be played on a bell character.</description>
         </key>
+        <key name="use-sixel" type="b">
+            <default>false</default>
+            <summary>Use Sixel</summary>
+            <description>If true, terminals will render sixel escape sequences.</description>
+        </key>
         <key name="window-width" type="i">
             <default>100</default>
             <summary>Window width.</summary>

guake/data/prefs.glade

@@ -342,7 +342,7 @@
                                     <property name="top-padding">12</property>
                                     <property name="left-padding">12</property>
                                     <child>
-                                      <!-- n-columns=3 n-rows=5 -->
+                                      <!-- n-columns=3 n-rows=6 -->
                                       <object class="GtkGrid">
                                         <property name="visible">True</property>
                                         <property name="can-focus">False</property>
@@ -533,6 +533,28 @@
                                             <property name="top-attach">4</property>
                                           </packing>
                                         </child>
+                                        <child>
+                                          <object class="GtkCheckButton" id="use_sixel">
+                                            <property name="label" translatable="yes">Render sixel escape sequences (images)</property>
+                                            <property name="visible">True</property>
+                                            <property name="can-focus">True</property>
+                                            <property name="receives-default">False</property>
+                                            <property name="halign">start</property>
+                                            <property name="use-underline">True</property>
+                                            <property name="draw-indicator">True</property>
+                                            <signal name="toggled" handler="on_use_sixel_toggled" swapped="no"/>
+                                          </object>
+                                          <packing>
+                                            <property name="left-attach">0</property>
+                                            <property name="top-attach">5</property>
+                                          </packing>
+                                        </child>
+                                        <child>
+                                          <placeholder/>
+                                        </child>
+                                        <child>
+                                          <placeholder/>
+                                        </child>
                                         <child>
                                           <placeholder/>
                                         </child>

guake/prefs.py

@@ -481,6 +481,10 @@ def on_use_audible_bell_toggled(self, chk):
         """Changes the value of use_audible_bell in dconf"""
         self.settings.general.set_boolean("use-audible-bell", chk.get_active())
 
+    def on_use_sixel_toggled(self, chk):
+        """Changes the value of enable_sixel in dconf"""
+        self.settings.general.set_boolean("use-sixel", chk.get_active())
+
     # scrolling tab
 
     def on_use_scrollbar_toggled(self, chk):
@@ -1182,6 +1186,10 @@ def load_configs(self):
         value = self.settings.general.get_boolean("use-audible-bell")
         self.get_widget("use_audible_bell").set_active(value)
 
+        # use sixel
+        value = self.settings.general.get_boolean("use-sixel")
+        self.get_widget("use_sixel").set_active(value)
+
         self._load_screen_settings()
 
         value = self.settings.general.get_boolean("quick-open-enable")

guake/terminal.py

@@ -211,6 +211,15 @@ def configure_terminal(self):
         if hasattr(self, "set_alternate_screen_scroll"):
             self.set_alternate_screen_scroll(True)
 
+        enable_sixel = client.get_boolean("use-sixel")
+        if enable_sixel:
+            # TODO: Once Sixel support is stable and there's a release with it built-in by default,
+            # we can use a version check like done above for other features.
+            try:
+                self.set_enable_sixel(True)
+            except:  # pylint: disable=bare-except
+                log.warn("set_enable_sixel is not supported by your version of VTE")
+
         self.set_can_default(True)
         self.set_can_focus(True)
 

releasenotes/notes/sixel_support-467783a27379bbe2.yaml

@@ -0,0 +1,9 @@
+release_summary: >
+  Add experimental support for displaying Sixels. This can be enabled with a new setting.
+
+features:
+  - add sixel support #1806
+
+known_issues:
+  - sixel support requires VTE to be compiled with `-Dsixel=true`, since support for it is still experimental.
+