This can cause lagging when scrolling as it causes us to repaint
on every scroll event. This wasn't historically a great problem,
but with smooth scrolling we get a lot more events, so this
now creates visible lagging on slower machines.
This makes kinetic scrolling work with viewports where the
content does not otherwise select for button or touch events,
such as testscrolledwindow's label.
With the changes in default CSS to make the default background transparent
we ran into issues where intermediate GdkWindow (for instance the
view_window in GtkViewport) where we didn't set an explicit background
(because before they were always covered). So instead of showing throught
the transparent windows were showing the default backgroind of the intermediate
window (i.e. black).
With this change we also needed to fix GtkViewport, as it was previously
relying on the bin and view windows to cover widget->window so that the
border was not visible if shadow_type was NONE.
This patch adds the GtkScrollablePolicy type property to GtkScrollable
and implements it in all subclasses. GtkScrolledWindow observes this
property to make a good guess about when to show/hide scrollbars for
height-for-width content.
Most scrollable children do not do height-for-width *yet* but
most certainly will (toolpalette, treeview, iconview, textview
widgets all TODO), for scrollable widgets that do have a minimum
and natural size, it's important for them to observe the state
of this property in order to properly drive the scroll adjustments
according to the desired GtkScrollablePolicy. This patch makes
GtkViewport do this.
Patch also adds tests/testscrolledwindow.c to display the effects
of this property.
It is just too annoying to have to implement these properties in
every scrollable. Instead, we now have ::min-content-height/width
in GtkScrolledWindow.
We also add GtkScrollablePolicy to determine how to size the
scrollable content.
The GtkScrollable interface provides "hadjustment" and "vadjustment"
properties that are used by GtkScrolledWindow. It replaces
the ::set_scroll_adjustment signal. The scrollable interface
also has ::min-display-width/height properties that can be
used to control the minimally visible part inside a scrolled window.
It doesn't make sense to keep them separate as GtkSizeRequest requires a
GtkWidget and GtkWidget implements GtkSizeRequest, so you can never have
one without the other.
It also makes the code a lot easier because no casts are required when
calling functions.
Also, the names would translate to gtk_widget_get_width() and people
agreed that this would be a too generic name, so a "preferred" was added
to the names.
So this patch moves the functions:
gtk_size_request_get_request_mode() => gtk_widget_get_request_mode()
gtk_size_request_get_width() => gtk_widget_get_preferred_width()
gtk_size_request_get_height() => gtk_widget_get_preferred_height()
gtk_size_request_get_size() => gtk_widget_get_preferred_size()
gtk_size_request_get_width_for_height() =>
gtk_widget_get_preferred_width_for_height()
gtk_size_request_get_height_for_width() =>
gtk_widget_get_preferred_height_for_width()
... and moves the corresponding vfuncs to the GtkWidgetClass.
The patch also renames the implementations of the vfuncs in widgets to
include the word "preferrred".
Make GtkViewport calculate widget-for-height as well as height-for-width
cases when setting the scroll adjustment values, also base the scrolling
on the minimum size instead of the natural size in the interest of showing
as much content as possible when the viewport is smaller than the natural
size.
