Commit 16b9e826 authored by Daniel Boles's avatar Daniel Boles

ScrolledWindow: Streamline/clarify the intro docs

 • intro: Clarify that external policy and/or adjustments can be used.
 • add(): Don’t waffle on about having to add a ViewPort since we handle
          that transparently for the user, so they can add() any widget.
 • Adjustment stuff: most of this was repeating the docs for Scrollbar,
                     so just refer the user to that. Also, mention how
                     policies NEVER and EXTERNAL interact with all this.
parent 3178a7a3
......@@ -56,31 +56,21 @@
* @Title: GtkScrolledWindow
* @See_also: #GtkScrollable, #GtkViewport, #GtkAdjustment
* GtkScrolledWindow is a #GtkBin subclass: it’s a container
* the accepts a single child widget. GtkScrolledWindow adds scrollbars
* to the child widget and optionally draws a beveled frame around the
* child widget.
* GtkScrolledWindow is a container that accepts a single child widget, makes
* that child scrollable using either internally added scrollbars or externally
* associated adjustments, and optionally draws a frame around the child.
* The scrolled window can work in two ways. Some widgets have native
* scrolling support; these widgets implement the #GtkScrollable interface.
* Widgets with native scroll support include #GtkTreeView, #GtkTextView,
* and #GtkLayout.
* For widgets that lack native scrolling support, the #GtkViewport
* widget acts as an adaptor class, implementing scrollability for child
* widgets that lack their own scrolling capabilities. Use #GtkViewport
* to scroll child widgets such as #GtkGrid, #GtkBox, and so on.
* If a widget has native scrolling abilities, it can be added to the
* GtkScrolledWindow with gtk_container_add(). If a widget does not, you
* must first add the widget to a #GtkViewport, then add the #GtkViewport
* to the scrolled window. gtk_container_add() will do this for you for
* widgets that don’t implement #GtkScrollable natively, so you can
* ignore the presence of the viewport.
* 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_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_add() has added a #GtkViewport for you, you can remove
* both your added child widget from the #GtkViewport and the #GtkViewport
* from the GtkScrolledWindow with either of the calls
* both your added child widget from the #GtkViewport, and the #GtkViewport
* from the GtkScrolledWindow, with either of these calls:
* |[<!-- language="C" -->
* gtk_container_remove (GTK_CONTAINER (scrolled_window),
* child_widget);
......@@ -89,15 +79,13 @@
* gtk_bin_get_child (GTK_BIN (scrolled_window)));
* ]|
* The position of the scrollbars is controlled by the scroll adjustments.
* See #GtkAdjustment for the fields in an adjustment — for
* #GtkScrollbar, used by GtkScrolledWindow, the “value” field
* represents the position of the scrollbar, which must be between the
* “lower” field and “upper - page_size.” The “page_size” field
* represents the size of the visible scrollable area. The
* “step_increment” and “page_increment” fields are used when the user
* asks to step down (using the small stepper arrows) or page down (using
* for example the PageDown key).
* 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
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