Trait gdk4::prelude::PaintableExt

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pub trait PaintableExt: 'static {
    // Required methods
    fn compute_concrete_size(
        &self,
        specified_width: f64,
        specified_height: f64,
        default_width: f64,
        default_height: f64
    ) -> (f64, f64);
    fn current_image(&self) -> Paintable;
    fn flags(&self) -> PaintableFlags;
    fn intrinsic_aspect_ratio(&self) -> f64;
    fn intrinsic_height(&self) -> i32;
    fn intrinsic_width(&self) -> i32;
    fn invalidate_contents(&self);
    fn invalidate_size(&self);
    fn snapshot(&self, snapshot: &impl IsA<Snapshot>, width: f64, height: f64);
    fn connect_invalidate_contents<F: Fn(&Self) + 'static>(
        &self,
        f: F
    ) -> SignalHandlerId;
    fn connect_invalidate_size<F: Fn(&Self) + 'static>(
        &self,
        f: F
    ) -> SignalHandlerId;
}
Expand description

Trait containing all Paintable methods.

Implementors

GLTexture, MemoryTexture, Paintable, Texture

Required Methods§

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fn compute_concrete_size( &self, specified_width: f64, specified_height: f64, default_width: f64, default_height: f64 ) -> (f64, f64)

Compute a concrete size for the Paintable.

Applies the sizing algorithm outlined in the CSS Image spec to the given @self. See that link for more details.

It is not necessary to call this function when both @specified_width and @specified_height are known, but it is useful to call this function in GtkWidget:measure implementations to compute the other dimension when only one dimension is given.

specified_width

the width @self could be drawn into or 0.0 if unknown

specified_height

the height @self could be drawn into or 0.0 if unknown

default_width

the width @self would be drawn into if no other constraints were given

default_height

the height @self would be drawn into if no other constraints were given

Returns
concrete_width

will be set to the concrete width computed

concrete_height

will be set to the concrete height computed

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fn current_image(&self) -> Paintable

Gets an immutable paintable for the current contents displayed by @self.

This is useful when you want to retain the current state of an animation, for example to take a screenshot of a running animation.

If the @self is already immutable, it will return itself.

Returns

An immutable paintable for the current contents of @self

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fn flags(&self) -> PaintableFlags

Get flags for the paintable.

This is oftentimes useful for optimizations.

See PaintableFlags for the flags and what they mean.

Returns

The PaintableFlags for this paintable

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fn intrinsic_aspect_ratio(&self) -> f64

Gets the preferred aspect ratio the @self would like to be displayed at.

The aspect ratio is the width divided by the height, so a value of 0.5 means that the @self prefers to be displayed twice as high as it is wide. Consumers of this interface can use this to preserve aspect ratio when displaying the paintable.

This is a purely informational value and does not in any way limit the values that may be passed to snapshot().

Usually when a @self returns nonzero values from intrinsic_width() and intrinsic_height() the aspect ratio should conform to those values, though that is not required.

If the @self does not have a preferred aspect ratio, it returns 0. Negative values are never returned.

Returns

the intrinsic aspect ratio of @self or 0 if none.

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fn intrinsic_height(&self) -> i32

Gets the preferred height the @self would like to be displayed at.

Consumers of this interface can use this to reserve enough space to draw the paintable.

This is a purely informational value and does not in any way limit the values that may be passed to snapshot().

If the @self does not have a preferred height, it returns 0. Negative values are never returned.

Returns

the intrinsic height of @self or 0 if none.

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fn intrinsic_width(&self) -> i32

Gets the preferred width the @self would like to be displayed at.

Consumers of this interface can use this to reserve enough space to draw the paintable.

This is a purely informational value and does not in any way limit the values that may be passed to snapshot().

If the @self does not have a preferred width, it returns 0. Negative values are never returned.

Returns

the intrinsic width of @self or 0 if none.

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fn invalidate_contents(&self)

Called by implementations of Paintable to invalidate their contents.

Unless the contents are invalidated, implementations must guarantee that multiple calls of snapshot() produce the same output.

This function will emit the invalidate-contents signal.

If a @self reports the PaintableFlags::CONTENTS flag, it must not call this function.

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fn invalidate_size(&self)

Called by implementations of Paintable to invalidate their size.

As long as the size is not invalidated, @self must return the same values for its intrinsic width, height and aspect ratio.

This function will emit the invalidate-size signal.

If a @self reports the PaintableFlags::SIZE flag, it must not call this function.

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fn snapshot(&self, snapshot: &impl IsA<Snapshot>, width: f64, height: f64)

Snapshots the given paintable with the given @width and @height.

The paintable is drawn at the current (0,0) offset of the @snapshot. If @width and @height are not larger than zero, this function will do nothing.

snapshot

a Snapshot to snapshot to

width

width to snapshot in

height

height to snapshot in

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fn connect_invalidate_contents<F: Fn(&Self) + 'static>( &self, f: F ) -> SignalHandlerId

Emitted when the contents of the @paintable change.

Examples for such an event would be videos changing to the next frame or the icon theme for an icon changing.

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fn connect_invalidate_size<F: Fn(&Self) + 'static>( &self, f: F ) -> SignalHandlerId

Emitted when the intrinsic size of the @paintable changes.

This means the values reported by at least one of intrinsic_width(), intrinsic_height() or intrinsic_aspect_ratio() has changed.

Examples for such an event would be a paintable displaying the contents of a toplevel surface being resized.

Implementors§