gui: hook up a zoom slider

The default size of the drawings is a bit small now, good for an overview but
not for identifying which drawing to use now. Add a zoom slider for that.

tuhigui/data/ui/MainWindow.ui

@@ -2,6 +2,12 @@
 <!-- Generated with glade 3.22.1 -->
 <interface>
   <requires lib="gtk+" version="3.20"/>
+  <object class="GtkAdjustment" id="adjustment_zoom">
+    <property name="upper">15</property>
+    <property name="step_increment">1.0000000002235174</property>
+    <property name="page_increment">1</property>
+    <signal name="value-changed" handler="_on_zoom_changed" swapped="no"/>
+  </object>
   <template class="MainWindow" parent="GtkApplicationWindow">
     <property name="can_focus">False</property>
     <property name="default_width">1000</property>
@@ -25,6 +31,9 @@
             <property name="can_focus">False</property>
             <property name="margin_left">10</property>
           </object>
+          <packing>
+            <property name="position">1</property>
+          </packing>
         </child>
         <child type="title">
           <placeholder/>
@@ -59,6 +68,55 @@
             <property name="position">2</property>
           </packing>
         </child>
+        <child>
+          <object class="GtkBox">
+            <property name="visible">True</property>
+            <property name="can_focus">False</property>
+            <child>
+              <object class="GtkImage">
+                <property name="visible">True</property>
+                <property name="can_focus">False</property>
+                <property name="icon_name">zoom-out-symbolic</property>
+              </object>
+              <packing>
+                <property name="expand">False</property>
+                <property name="fill">True</property>
+                <property name="position">0</property>
+              </packing>
+            </child>
+            <child>
+              <object class="GtkScale" id="scale_zoom">
+                <property name="width_request">100</property>
+                <property name="visible">True</property>
+                <property name="can_focus">True</property>
+                <property name="adjustment">adjustment_zoom</property>
+                <property name="round_digits">0</property>
+                <property name="draw_value">False</property>
+              </object>
+              <packing>
+                <property name="expand">False</property>
+                <property name="fill">True</property>
+                <property name="position">1</property>
+              </packing>
+            </child>
+            <child>
+              <object class="GtkImage">
+                <property name="visible">True</property>
+                <property name="can_focus">False</property>
+                <property name="icon_name">zoom-in-symbolic</property>
+              </object>
+              <packing>
+                <property name="expand">False</property>
+                <property name="fill">True</property>
+                <property name="position">2</property>
+              </packing>
+            </child>
+          </object>
+          <packing>
+            <property name="pack_type">end</property>
+            <property name="position">3</property>
+          </packing>
+        </child>
       </object>
     </child>
     <child>

tuhigui/drawing.py

@@ -38,6 +38,7 @@ class Drawing(Gtk.Box):
         Config.instance().connect('notify::orientation', self._on_orientation_changed)
 
         self.json_data = json_data
+        self._zoom = 0
         self.refresh()  # sets self.svg
 
         self.timestamp = self.svg.timestamp
@@ -47,18 +48,34 @@ class Drawing(Gtk.Box):
         self.refresh()
 
     def refresh(self):
-        self.svg = svg = JsonSvg(self.json_data, self.orientation)
+        self.svg = JsonSvg(self.json_data, self.orientation)
+        self.pixbuf = GdkPixbuf.Pixbuf.new_from_file_at_scale(filename=self.svg.filename,
+                                                              width=1000,
+                                                              height=1000,
+                                                              preserve_aspect_ratio=True)
+        self.redraw()
 
-        pixbuf = GdkPixbuf.Pixbuf.new_from_file_at_scale(filename=svg.filename,
-                                                         width=250,
-                                                         height=250,
-                                                         preserve_aspect_ratio=True)
-        self.image_svg.set_from_pixbuf(pixbuf)
+    def redraw(self):
+        pb = self.pixbuf.scale_simple(250 + (self.zoom * 50),
+                                 250 + (self.zoom * 50),
+                                 GdkPixbuf.InterpType.BILINEAR)
+        self.image_svg.set_from_pixbuf(pb)
 
     @GObject.Property
     def name(self):
         return "drawing"
 
+    @GObject.Property
+    def zoom(self):
+        return self._zoom
+
+    @zoom.setter
+    def zoom(self, zoom):
+        if zoom == self._zoom:
+            return
+        self._zoom = zoom
+        self.redraw()
+
     @Gtk.Template.Callback('_on_download_button_clicked')
     def _on_download_button_clicked(self, button):
         dialog = Gtk.FileChooserDialog(_('Please choose a file'),

tuhigui/drawingperspective.py

@@ -101,6 +101,7 @@ class DrawingPerspective(Gtk.Stack):
         super().__init__(*args, **kwargs)
         self.known_drawings = {}  # type {timestamp: Drawing()}
         self.flowboxes = {}
+        self._zoom = 0
 
     def _cache_drawings(self, device, pspec):
         # The config backend filters duplicates anyway, so don't care here
@@ -176,6 +177,19 @@ class DrawingPerspective(Gtk.Stack):
     def name(self):
         return "drawing_perspective"
 
+    @GObject.Property
+    def zoom(self):
+        return self._zoom
+
+    @zoom.setter
+    def zoom(self, zoom):
+        if zoom == self._zoom:
+            return
+
+        self._zoom = zoom
+        for ts, drawing in self.known_drawings.items():
+            drawing.zoom = zoom
+
     def _on_connected(self, device, pspec):
         # Turns out we don't really care about whether the device is
         # connected or not, it has little effect on how we work here

tuhigui/window.py

@@ -237,3 +237,8 @@ class MainWindow(Gtk.ApplicationWindow):
     def _on_orientation_changed(self, action, label):
         action.set_state(label)
         Config.instance().orientation = label.get_string()  # this is a GVariant
+
+    @Gtk.Template.Callback('_on_zoom_changed')
+    def _on_zoom_changed(self, adjustment):
+        dp = self._get_child('drawing_perspective')
+        dp.zoom = int(adjustment.get_value())