BreakpointBin

A widget that changes layout based on available size.

<picture> <source srcset="breakpoint-bin-dark.png" media="(prefers-color-scheme: dark)"> <img src="breakpoint-bin.png" alt="breakpoint-bin"> </picture>

`AdwBreakpointBin` provides a way to use breakpoints without [class@Window] or [class@ApplicationWindow]. It can be useful for limiting breakpoints to a single page and similar purposes. Most applications shouldn't need it.

`AdwBreakpointBin` is similar to [class@Bin]. It has one child, set via the [property@BreakpointBin:child] property.

When `AdwBreakpointBin` is resized, its child widget can rearrange its layout at specific thresholds.

The thresholds and layout changes are defined via [class@Breakpoint] objects. They can be added using [method@BreakpointBin.add_breakpoint].

Each breakpoint has a condition, specifying the bin's size and/or aspect ratio, and setters that automatically set object properties when that happens. The [signal@Breakpoint:AdwBreakpointBin:apply] and [signal@Breakpoint:AdwBreakpointBin:unapply] can be used instead for more complex scenarios.

Breakpoints are only allowed to modify widgets inside the `AdwBreakpointBin`, but not on the `AdwBreakpointBin` itself or any other widgets.

If multiple breakpoints can be used for the current size, the last one is always picked. The current breakpoint can be tracked using the [ property@BreakpointBin:current-breakpoint] property.

If none of the breakpoints can be used, that property will be set to `NULL`, and the original property values will be used instead.

Minimum Size

Adding a breakpoint to `AdwBreakpointBin` will result in it having no minimum size. The [property@Gtk.Widget:width-request] and [ property@Gtk.Widget:height-request] properties must always be set when using breakpoints, indicating the smallest size you want to support.

The minimum size and breakpoint conditions must be carefully selected so that the child widget completely fits. If it doesn't, it will overflow and a warning message will be printed.

When choosing minimum size, consider translations and text scale factor changes. Make sure to leave enough space for text labels, and enable ellipsizing or wrapping if they might not fit.

For [class@Gtk.Label] this can be done via [property@Gtk.Label:ellipsize], or via [property@Gtk.Label:wrap] together with [ property@Gtk.Label:wrap-mode].

For buttons, use [property@Gtk.Button:can-shrink], [property@Gtk.MenuButton:can-shrink], [property@Adw.SplitButton:can-shrink], or [ property@Adw.ButtonContent:can-shrink].

Example

```c GtkWidget *bin, *child; AdwBreakpoint *breakpoint;

bin = adw_breakpoint_bin_new (); gtk_widget_set_size_request (bin, 150, 150);

child = gtk_label_new ("Wide"); gtk_label_set_ellipsize (GTK_LABEL (label), PANGO_ELLIPSIZE_END); gtk_widget_add_css_class (child, "title-1"); adw_breakpoint_bin_set_child (ADW_BREAKPOINT_BIN (bin), child);

breakpoint = adw_breakpoint_new (adw_breakpoint_condition_parse ("max-width: 200px")); adw_breakpoint_add_setters (breakpoint, G_OBJECT (child ), "label", "Narrow", NULL); adw_breakpoint_bin_add_breakpoint (ADW_BREAKPOINT_BIN (bin), breakpoint); ```

The bin has a single label inside it, displaying "Wide". When the bin's width is smaller than or equal to 200px, it changes to "Narrow".

`AdwBreakpointBin` as `GtkBuildable`

`AdwBreakpointBin` allows adding `AdwBreakpoint` objects as children.

Example of an `AdwBreakpointBin` UI definition:

```xml <object class="AdwBreakpointBin"> <property name="width-request">150</property> <property name="height-request" >150</property> <property name="child"> <object class="GtkLabel" id="child"> <property name="label">Wide< /property> <property name="ellipsize">end</property> <style> <class name="title-1"/> </style> </object > </property> <child> <object class="AdwBreakpoint"> <condition>max-width: 200px</condition> <setter object="child" property="label">Narrow</setter> </object> </child> </object> ```

See [class@Breakpoint] documentation for details.