Greatly enhanced thumbnail scrolling logic/simplified it

src/new-src/core/containers/image_list_scroll.py

@@ -14,8 +14,14 @@ class ImageListScroll(Gtk.ScrolledWindow):
     def __init__(self):
         super(ImageListScroll, self).__init__()
 
+        self.image_list_widget = None
+        self.size  = 0
+        self.start = 0
+        self.end   = 9
+
         self._setup_styling()
         self._setup_signals()
+        self._subscribe_to_events()
         self._load_widgets()
 
         self.show_all()
@@ -28,34 +34,37 @@ class ImageListScroll(Gtk.ScrolledWindow):
         self.connect("edge-reached", self._handle_edge_reached)
         self.connect("edge-overshot", self._handle_edge_reached)
 
+    def _subscribe_to_events(self):
+        event_system.subscribe("update_list_size_constraints", self._update_list_size_constraints)
+
     def _load_widgets(self):
-        self.add(ImageList())
+        self.image_list_widget = ImageList()
+        self.add(self.image_list_widget)
+
+    # TODO: Setup to load range start/end values from settings,
+    # NOTE: Must align with ImageList start/end limits too
+    def _update_list_size_constraints(self, size):
+        self.size  = size
+        self.start = 0
+        self.end   = 9
 
     def _handle_edge_reached(self, widget, edge):
         img_list = widget.get_children()[0].get_children()[0]
-        children   = img_list.get_children()
-        start, end = None, None
-        size       = len(children)
-
-        for i, child in enumerate(children):
-            if start in (None, "") and child.is_visible():
-                start = i
-
-            if end in (None, "") and not start in (None, "") and not \
-                child.is_visible():
-                    end = (i - 1)
-                    break
-
-        if not end:
-            end = size - 1
+        children = self.image_list_widget.get_children()
 
         if edge == Gtk.PositionType.TOP:
-            if start >= 1 and not end in (None, ""):
-                start -= 1
-                children[end].hide()
-                children[start].show()
+            if self.start >= 1:
+                self.start -= 1
+                children[self.end].hide()
+                children[self.start].show()
+                self.end -= 1
         if edge == Gtk.PositionType.BOTTOM:
-            if not end in (None, "") and not (end + 1) == size:
-                end += 1
-                children[start].hide()
-                children[end].show()
+            if (self.end + 1) < self.size:
+                self.end += 1
+                children[self.start].hide()
+
+                if not children[self.end].is_loaded:
+                    children[self.end].load_pixbuf()
+
+                children[self.end].show()
+                self.start += 1

src/new-src/core/widgets/image.py

@@ -23,6 +23,7 @@ class Image(Gtk.EventBox):
 
         self._thumbnail_with   = settings.get_thumbnail_with()
         self._thumbnail_height = settings.get_thumbnail_height()
+        self.is_loaded = False
         self.image     = None
         self.path      = path
 
@@ -56,6 +57,7 @@ class Image(Gtk.EventBox):
         self.set_from_pixbuf( self.get_pixbuf_data(self.path, \
                                                     self._thumbnail_with, \
                                                     self._thumbnail_height) )
+        self.is_loaded = True
 
     def get_pixbuf_data(self, path, w = 126, h = 126):
         path   = self.path if not path else path

src/new-src/core/widgets/image_list.py

@@ -63,29 +63,21 @@ class ImageList(Gtk.Box):
         for file in paths:
             self.add( Image(file) )
 
-        self.pre_fill_gtkimgs()
+        event_system.emit("update_list_size_constraints", (len(paths),))
         self.show_range()
 
-    def pre_fill_gtkimgs(self):
-        children = self.get_children()
-        for child in children:
-            self.load_pixbuf_to_target(child)
-
-    @daemon_threaded
-    def load_pixbuf_to_target(self, child):
-        child.load_pixbuf()
-
+    # TODO: Setup to load range start/end values from settings
     def show_range(self, i = 0, j = 9):
         children = self.get_children()
         if len(children) <= j:
             j = len(children) - 1
 
         while i <= j:
-            self.show_at_index(children[i])
+            child = children[i]
+            self.load_pixbuf_threaded(child)
+            child.show()
             i += 1
 
-    def show_at_index(self, child = None):
-        if not child:
-            return
-
-        child.show()
+    @daemon_threaded
+    def load_pixbuf_threaded(self, child):
+        child.load_pixbuf()