GtkScrolledWindow is a container that accepts a single child widget and makes
that child scrollable using either internally added scrollbars or externally
associated adjustments.
Widgets with native scrolling support, i.e. those whose classes implement the
#GtkScrollable interface, are added directly. For other types of widget, the
class #GtkViewport acts as an adaptor, giving scrollability to other widgets.
GtkScrolledWindow’s implementation of gtk.container.Container.add intelligently
accounts for whether or not the added child is a #GtkScrollable. If it isn’t,
#GtkScrolledWindow wraps the child in a #GtkViewport and adds that for you.
Therefore, you can just add any child widget and not worry about the details.
If gtk.container.Container.add has added a #GtkViewport for you, you can remove
both your added child widget from the #GtkViewport, and the #GtkViewport
from the GtkScrolledWindow, like this:
GtkWidget *scrolled_window = gtk_scrolled_window_new (NULL, NULL);
GtkWidget *child_widget = gtk_button_new ();
// GtkButton is not a GtkScrollable, so GtkScrolledWindow will automatically// add a GtkViewport.
gtk_container_add (GTK_CONTAINER (scrolled_window),
child_widget);
// Either of these will result in child_widget being unparented:
gtk_container_remove (GTK_CONTAINER (scrolled_window),
child_widget);
// or
gtk_container_remove (GTK_CONTAINER (scrolled_window),
gtk_bin_get_child (GTK_BIN (scrolled_window)));
Unless #GtkScrolledWindow:policy is GTK_POLICY_NEVER or GTK_POLICY_EXTERNAL,
GtkScrolledWindow adds internal #GtkScrollbar widgets around its child. The
scroll position of the child, and if applicable the scrollbars, is controlled
by the #GtkScrolledWindow:hadjustment and #GtkScrolledWindow:vadjustment
that are associated with the GtkScrolledWindow. See the docs on #GtkScrollbar
for the details, but note that the “step_increment” and “page_increment”
fields are only effective if the policy causes scrollbars to be present.
If a GtkScrolledWindow doesn’t behave quite as you would like, or
doesn’t have exactly the right layout, it’s very possible to set up
your own scrolling with #GtkScrollbar and for example a #GtkGrid.
Touch support
GtkScrolledWindow has built-in support for touch devices. When a
touchscreen is used, swiping will move the scrolled window, and will
expose 'kinetic' behavior. This can be turned off with the
#GtkScrolledWindow:kinetic-scrolling property if it is undesired.
GtkScrolledWindow also displays visual 'overshoot' indication when
the content is pulled beyond the end, and this situation can be
captured with the #GtkScrolledWindow::edge-overshot signal.
If no mouse device is present, the scrollbars will overlayed as
narrow, auto-hiding indicators over the content. If traditional
scrollbars are desired although no mouse is present, this behaviour
can be turned off with the #GtkScrolledWindow:overlay-scrolling
property.
CSS nodes
GtkScrolledWindow has a main CSS node with name scrolledwindow.
It uses subnodes with names overshoot and undershoot to
draw the overflow and underflow indications. These nodes get
the .left, .right, .top or .bottom style class added depending
on where the indication is drawn.
GtkScrolledWindow also sets the positional style classes (.left,
.right, .top, .bottom) and style classes related to overlay
scrolling (.overlay-indicator, .dragging, .hovering) on its scrollbars.
If both scrollbars are visible, the area where they meet is drawn
with a subnode named junction.
GtkScrolledWindow is a container that accepts a single child widget and makes that child scrollable using either internally added scrollbars or externally associated adjustments.
Widgets with native scrolling support, i.e. those whose classes implement the #GtkScrollable interface, are added directly. For other types of widget, the class #GtkViewport acts as an adaptor, giving scrollability to other widgets. GtkScrolledWindow’s implementation of gtk.container.Container.add intelligently accounts for whether or not the added child is a #GtkScrollable. If it isn’t, #GtkScrolledWindow wraps the child in a #GtkViewport and adds that for you. Therefore, you can just add any child widget and not worry about the details.
If gtk.container.Container.add has added a #GtkViewport for you, you can remove both your added child widget from the #GtkViewport, and the #GtkViewport from the GtkScrolledWindow, like this:
Unless #GtkScrolledWindow:policy is GTK_POLICY_NEVER or GTK_POLICY_EXTERNAL, GtkScrolledWindow adds internal #GtkScrollbar widgets around its child. The scroll position of the child, and if applicable the scrollbars, is controlled by the #GtkScrolledWindow:hadjustment and #GtkScrolledWindow:vadjustment that are associated with the GtkScrolledWindow. See the docs on #GtkScrollbar for the details, but note that the “step_increment” and “page_increment” fields are only effective if the policy causes scrollbars to be present.
If a GtkScrolledWindow doesn’t behave quite as you would like, or doesn’t have exactly the right layout, it’s very possible to set up your own scrolling with #GtkScrollbar and for example a #GtkGrid.
Touch support
GtkScrolledWindow has built-in support for touch devices. When a touchscreen is used, swiping will move the scrolled window, and will expose 'kinetic' behavior. This can be turned off with the #GtkScrolledWindow:kinetic-scrolling property if it is undesired.
GtkScrolledWindow also displays visual 'overshoot' indication when the content is pulled beyond the end, and this situation can be captured with the #GtkScrolledWindow::edge-overshot signal.
If no mouse device is present, the scrollbars will overlayed as narrow, auto-hiding indicators over the content. If traditional scrollbars are desired although no mouse is present, this behaviour can be turned off with the #GtkScrolledWindow:overlay-scrolling property.
CSS nodes
GtkScrolledWindow has a main CSS node with name scrolledwindow.
It uses subnodes with names overshoot and undershoot to draw the overflow and underflow indications. These nodes get the .left, .right, .top or .bottom style class added depending on where the indication is drawn.
GtkScrolledWindow also sets the positional style classes (.left, .right, .top, .bottom) and style classes related to overlay scrolling (.overlay-indicator, .dragging, .hovering) on its scrollbars.
If both scrollbars are visible, the area where they meet is drawn with a subnode named junction.