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Features/Optimize TreeViews (view source)
Revision as of 07:28, 17 November 2014
, 07:28, 17 November 2014→Detailed Description
* Sugar CellRendererIcon has too much logic inside. It should only handle how to render itself.
* 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.
* Sugar CellRendererIcon is connected to many signals. Just detaching them while scrolling provides a performance boost.
* Sugar CellRendererIcon could benefit from caching values instead of calculating them on each render.
* Sugar CellRendererIcon could benefit from caching values instead of calculating them on each render.
* 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 ===
=== GTK+ concepts ===
* GtkCellRenderer — An object for rendering a single cell https://developer.gnome.org/gtk3/stable/GtkCellRenderer
* GtkCellRenderer — An object for rendering a single cell https://developer.gnome.org/gtk3/stable/GtkCellRenderer
== Benefit to Sugar ==
== Benefit to Sugar ==