Breakpoint

Added in version 1.4.

class Breakpoint(**properties: Any)

Superclasses: Object

Implemented Interfaces: Buildable

Describes a breakpoint for Window or Dialog.

Breakpoints are used to create adaptive UI, allowing to change the layout depending on available size.

Breakpoint is a size threshold, specified by its condition, as well as one or more setters.

Each setter has a target object, a property and a value. When a breakpoint is applied, each setter sets the target property on their target object to the specified value, and reset it back to the original value when it’s unapplied.

For more complicated scenarios, apply and unapply can be used instead.

Breakpoints can be used within Window, ApplicationWindow, Dialog or BreakpointBin.

AdwBreakpoint as GtkBuildable:

AdwBreakpoint supports specifying its condition via the <condition> element. The contents of the element must be a string in a format accepted by parse.

It also supports adding setters via the <setter> element. Each <setter> element must have the object attribute specifying the target object, and the property attribute specifying the property name. The contents of the element are used as the setter value.

For G_TYPE_OBJECT and G_TYPE_BOXED derived properties, empty contents are treated as NULL.

Setter values can be translated with the usual translatable, context and comments attributes.

Example of an AdwBreakpoint UI definition:

<object class="AdwBreakpoint">
  <condition>max-width: 400px</condition>
  <setter object="button" property="visible">True</setter>
  <setter object="box" property="orientation">vertical</setter>
  <setter object="page" property="title" translatable="yes">Example</setter>
</object>

Constructors

class Breakpoint

classmethod new(condition: BreakpointCondition) → Breakpoint

Creates a new AdwBreakpoint with condition.

Added in version 1.4.

Parameters:

condition – the condition

Methods

class Breakpoint

add_setter(object: Object, property: str, value: Any) → None

Adds a setter to self.

The setter will automatically set property on object to value when applying the breakpoint, and set it back to its original value upon unapplying it.

::: note

Setting properties to their original values does not work for properties that have irreversible side effects. For example, changing label while icon_name is set will reset the icon. However, resetting the label will not set icon-name to its original value.

Use the apply and unapply signals for those properties instead, as follows:

static void
breakpoint_apply_cb (MyWidget *self)
{
  gtk_button_set_icon_name (self->button, "go-previous-symbolic");
}

static void
breakpoint_apply_cb (MyWidget *self)
{
  gtk_button_set_label (self->button, _("_Back"));
}

// ...

g_signal_connect_swapped (breakpoint, "apply",
                          G_CALLBACK (breakpoint_apply_cb), self);
g_signal_connect_swapped (breakpoint, "unapply",
                          G_CALLBACK (breakpoint_unapply_cb), self);

Added in version 1.4.

Parameters:

• object – the target object

• property – the target property

• value – the value to set

add_setters(objects: Sequence[Object], names: Sequence[str], values: Sequence[Any]) → None

Adds multiple setters to self.

See add_setter.

Example:

adw_breakpoint_add_setters (breakpoint,
                            G_OBJECT (box), "orientation", GTK_ORIENTATION_VERTICAL,
                            G_OBJECT (button), "halign", GTK_ALIGN_FILL,
                            G_OBJECT (button), "valign", GTK_ALIGN_END,
                            NULL);

Added in version 1.4.

Parameters:

• objects

• names

• values

get_condition() → BreakpointCondition | None

Gets the condition for self.

Added in version 1.4.

set_condition(condition: BreakpointCondition | None = None) → None

Sets the condition for self.

Added in version 1.4.

Parameters:

condition – the new condition

Properties

class Breakpoint

props.condition: BreakpointCondition

The breakpoint’s condition.

Added in version 1.4.

Signals

class Breakpoint.signals

apply() → None

Emitted when the breakpoint is applied.

This signal is emitted after the setters have been applied.

Added in version 1.4.

unapply() → None

Emitted when the breakpoint is unapplied.

This signal is emitted before resetting the setter values.

Added in version 1.4.