Don't crash if the book have bookmarks saved, but can't open the preview

If the preview can't be opened or created, create a image with a number
showing the page number.

Signed-off-by: Gonzalo Odiard <gonzalo@laptop.org>

2 files changed, 41 insertions, 1 deletions

diff --git a/linkbutton.py b/linkbutton.py
index 3fd4579..075fdb3 100644
--- a/linkbutton.py
+++ b/linkbutton.py
@@ -50,7 +50,11 @@ class LinkButton(TrayButton, GObject.GObject):
         # it as single byte string:
         if isinstance(color, unicode):
             color = str(color)
-        self.set_image(buf, color.split(',')[1], color.split(',')[0])
+        if buf is not None:
+            self.set_image(buf, color.split(',')[1], color.split(',')[0])
+        else:
+            self.set_empty_image(page, color.split(',')[1],
+                                 color.split(',')[0])
 
         self.page = int(page)
         info = title + '\n' + owner
@@ -87,6 +91,39 @@ class LinkButton(TrayButton, GObject.GObject):
         self.set_icon_widget(img)
         img.show()
 
+    def set_empty_image(self, page, fill='#0000ff', stroke='#4d4c4f'):
+        img = Gtk.Image()
+
+        bg_width, bg_height = style.zoom(120), style.zoom(110)
+        bg_surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, bg_width,
+                                        bg_height)
+        context = cairo.Context(bg_surface)
+        # draw a rectangle in the background with the selected colors
+        context.set_line_width(style.zoom(10))
+        context.set_source_rgba(*style.Color(fill).get_rgba())
+        context.rectangle(0, 0, bg_width, bg_height)
+        context.fill_preserve()
+        context.set_source_rgba(*style.Color(stroke).get_rgba())
+        context.stroke()
+
+        # add the page number
+        context.set_font_size(style.zoom(60))
+        text = str(page)
+        x, y = bg_width / 2, bg_height / 2
+
+        xbearing, ybearing, width, height, xadvance, yadvance = \
+            context.text_extents(text)
+        context.move_to(x - width / 2, y + height / 2)
+        context.show_text(text)
+        context.stroke()
+
+        pixbuf_bg = Gdk.pixbuf_get_from_surface(bg_surface, 0, 0,
+                                                bg_width, bg_height)
+
+        img.set_from_pixbuf(pixbuf_bg)
+        self.set_icon_widget(img)
+        img.show()
+
     def setup_rollover_options(self, info):
         palette = Palette(info, text_maxlen=50)
         self.set_palette(palette)
diff --git a/readactivity.py b/readactivity.py
index 2714ccc..1aed546 100644
--- a/readactivity.py
+++ b/readactivity.py
@@ -1202,6 +1202,9 @@ class ReadActivity(activity.Activity):
             return None
 
         window = self.canvas.get_window()
+        if window is None:
+            return None
+
         alloc = self.canvas.get_allocation()
 
         dummy_cr = Gdk.cairo_create(window)