Features/Optimize TreeViews: Difference between revisions

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* Sugar CellRendererIcon has too much logic inside. It should only handle how to render itself.

In particular, a CellRenderer is not a Widget, then do not have event to know when the mouse interact,

then needed attach to the events on the treeview [https://github.com/sugarlabs/sugar-toolkit-gtk3/blob/master/src/sugar3/graphics/icon.py#L826]

* Sugar CellRendererIcon is connected to many signals. Just detaching them while scrolling provides a performance boost.

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* Sugar CellRendererIcon could benefit from caching values instead of calculating them on each render.

~~We couldn't find what's wrong with~~ the Journal. We guess there is a DBus blocking call, but we could't confirm that.

* There are a additional block in the Journal. That is not addressed by this feature, we guess there is a DBus blocking call,

but we could't confirm that.

=== Implementation ===

* ScrollingDetector: A new class ScrollingDetector allow simplify slow operations while the treeview is scrolling.

To use it, just do:

scrolling_detector = ScrollingDetector(self._scrolled_window)

scrolling_detector.connect_treeview(self._tree_view)

* CellRendererIcon changes:

The CellRendererIcon is not a widget, then, do not receive events when the mouse

enter or leaves, and all the logic in the CellRendererInvoker is more complex than should be.

Worst, we had 6 different CellRendererIcons in the Journal, then we simplified (and solved issues) implementing a

TreeViewInvoker. The TreeView knows where is every cell then the code is much more simple.

The ObjectPalettes was created in the mouse enter callback, then if a user moved

the mouse cursor over the activity icons, many palettes were created, and that palette creation is expensive [http://bugs.sugarlabs.org/ticket/4343].

Moving the palette creation to the treeview, we can create the palette when the mouse was in a cell for a specified timeout and not before.

=== GTK+ concepts ===

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* GtkCellRenderer — An object for rendering a single cell https://developer.gnome.org/gtk3/stable/GtkCellRenderer

== Benefit to Sugar ==

@@ Line 25: / Line 25: @@
 * Sugar CellRendererIcon has too much logic inside.  It should only handle how to render itself.
+In particular, a CellRenderer is not a Widget, then do not have event to know when the mouse interact,
+then needed attach to the events on the treeview [https://github.com/sugarlabs/sugar-toolkit-gtk3/blob/master/src/sugar3/graphics/icon.py#L826]
 * Sugar CellRendererIcon is connected to many signals.  Just detaching them while scrolling provides a performance boost.
@@ Line 30: / Line 32: @@
 * Sugar CellRendererIcon could benefit from caching values instead of calculating them on each render.
-We couldn't find what's wrong with the Journal.  We guess there is a DBus blocking call, but we could't confirm that.
+* There are a additional block in the Journal. That is not addressed by this feature, we guess there is a DBus blocking call,
+but we could't confirm that.
+=== Implementation ===
+* ScrollingDetector: A new class ScrollingDetector allow simplify slow operations while the treeview is scrolling.
+To use it, just do:
+ scrolling_detector = ScrollingDetector(self._scrolled_window)
+ scrolling_detector.connect_treeview(self._tree_view)
+* CellRendererIcon changes:
+The CellRendererIcon is not a widget, then, do not receive events when the mouse
+enter or leaves, and all the logic in the CellRendererInvoker is more complex than should be.
+Worst, we had 6 different CellRendererIcons in the Journal, then we simplified (and solved issues) implementing a
+TreeViewInvoker. The TreeView knows where is every cell then the code is much more simple.
+The ObjectPalettes was created in the mouse enter callback, then if a user moved
+the mouse cursor over the activity icons, many palettes were created, and that palette creation is expensive [http://bugs.sugarlabs.org/ticket/4343].
+Moving the palette creation to the treeview, we can create the palette when the mouse was in a cell for a specified timeout and not before.
 === GTK+ concepts ===
@@ Line 39: / Line 61: @@
 * GtkCellRenderer — An object for rendering a single cell https://developer.gnome.org/gtk3/stable/GtkCellRenderer
 == Benefit to Sugar ==