Struct gdk4::DmabufTextureBuilder

pub struct DmabufTextureBuilder { /* private fields */ }

Available on crate feature v4_14 only.

DmabufTextureBuilder is a builder used to construct Texture objects from DMA buffers.

DMA buffers are commonly called dma-bufs.

DMA buffers are a feature of the Linux kernel to enable efficient buffer and memory sharing between hardware such as codecs, GPUs, displays, cameras and the kernel drivers controlling them. For example, a decoder may want its output to be directly shared with the display server for rendering without a copy.

Any device driver which participates in DMA buffer sharing, can do so as either the exporter or importer of buffers (or both).

The memory that is shared via DMA buffers is usually stored in non-system memory (maybe in device’s local memory or something else not directly accessible by the CPU), and accessing this memory from the CPU may have higher-than-usual overhead.

In particular for graphics data, it is not uncommon that data consists of multiple separate blocks of memory, for example one block for each of the red, green and blue channels. These blocks are called planes. DMA buffers can have up to four planes. Even if the memory is a single block, the data can be organized in multiple planes, by specifying offsets from the beginning of the data.

DMA buffers are exposed to user-space as file descriptors allowing to pass them between processes. If a DMA buffer has multiple planes, there is one file descriptor per plane.

The format of the data (for graphics data, essentially its colorspace) is described by a 32-bit integer. These format identifiers are defined in the header file drm_fourcc.h and commonly referred to as fourcc values, since they are identified by 4 ASCII characters. Additionally, each DMA buffer has a modifier, which is a 64-bit integer that describes driver-specific details of the memory layout, such as tiling or compression.

For historical reasons, some producers of dma-bufs don’t provide an explicit modifier, but instead return DMA_FORMAT_MOD_INVALID to indicate that their modifier is implicit. GTK tries to accommodate this situation by accepting DMA_FORMAT_MOD_INVALID as modifier.

The operation of DmabufTextureBuilder is quite simple: Create a texture builder, set all the necessary properties, and then call build() to create the new texture.

The required properties for a dma-buf texture are

• The width and height in pixels

• The fourcc code and modifier which identify the format and memory layout of the dma-buf

• The file descriptor, offset and stride for each of the planes

DmabufTextureBuilder can be used for quick one-shot construction of textures as well as kept around and reused to construct multiple textures.

For further information, see

• The Linux kernel documentation

• The header file drm_fourcc.h

Properties

display

The display that this texture will be used on.

Readable | Writeable

fourcc

The format of the texture, as a fourcc value.

Readable | Writeable

height

The height of the texture.

Readable | Writeable

modifier

The modifier.

Readable | Writeable

n-planes

The number of planes of the texture.

Note that you can set properties for other planes, but they will be ignored when constructing the texture.

Readable | Writeable

premultiplied

Whether the alpha channel is premultiplied into the others.

Only relevant if the format has alpha.

Readable | Writeable

update-region

The update region for update-texture.

Readable | Writeable

update-texture

The texture update-region is an update for.

Readable | Writeable

width

The width of the texture.

Readable | Writeable

Implementations

impl DmabufTextureBuilder

pub fn new() -> DmabufTextureBuilder

Creates a new texture builder.

Returns

the new GdkTextureBuilder

pub fn display(&self) -> Display

Returns the display that this texture builder is associated with.

Returns

the display

pub fn fd(&self, plane: u32) -> i32

Gets the file descriptor for a plane.

plane

the plane to get the fd for

Returns

the file descriptor

pub fn fourcc(&self) -> u32

Gets the format previously set via gdk_dmabuf_texture_builder_set_fourcc() or 0 if the format wasn’t set.

The format is specified as a fourcc code.

Returns

The format

pub fn height(&self) -> u32

Gets the height previously set via gdk_dmabuf_texture_builder_set_height() or 0 if the height wasn’t set.

Returns

The height

pub fn modifier(&self) -> u64

Gets the modifier value.

Returns

the modifier

pub fn n_planes(&self) -> u32

Gets the number of planes.

Returns

The number of planes

pub fn offset(&self, plane: u32) -> u32

Gets the offset value for a plane.

plane

the plane to get the offset for

Returns

the offset

pub fn is_premultiplied(&self) -> bool

Whether the data is premultiplied.

Returns

whether the data is premultiplied

pub fn stride(&self, plane: u32) -> u32

Gets the stride value for a plane.

plane

the plane to get the stride for

Returns

the stride

pub fn update_region(&self) -> Option<Region>

Gets the region previously set via gdk_dmabuf_texture_builder_set_update_region() or None if none was set.

Returns

The region

pub fn update_texture(&self) -> Option<Texture>

Gets the texture previously set via gdk_dmabuf_texture_builder_set_update_texture() or None if none was set.

Returns

The texture

pub fn width(&self) -> u32

Gets the width previously set via gdk_dmabuf_texture_builder_set_width() or 0 if the width wasn’t set.

Returns

The width

pub fn set_display(&self, display: &impl IsA<Display>)

Sets the display that this texture builder is associated with.

The display is used to determine the supported dma-buf formats.

display

the display

pub fn set_fd(&self, plane: u32, fd: i32)

Sets the file descriptor for a plane.

plane

the plane to set the fd for

fd

the file descriptor

pub fn set_fourcc(&self, fourcc: u32)

Sets the format of the texture.

The format is specified as a fourcc code.

The format must be set before calling GLTextureBuilder::build().

fourcc

the texture’s format or 0 to unset

pub fn set_height(&self, height: u32)

Sets the height of the texture.

The height must be set before calling GLTextureBuilder::build().

height

the texture’s height or 0 to unset

pub fn set_modifier(&self, modifier: u64)

Sets the modifier.

modifier

the modifier value

pub fn set_n_planes(&self, n_planes: u32)

Sets the number of planes of the texture.

n_planes

the number of planes

pub fn set_offset(&self, plane: u32, offset: u32)

Sets the offset for a plane.

plane

the plane to set the offset for

offset

the offset value

pub fn set_premultiplied(&self, premultiplied: bool)

Sets whether the data is premultiplied.

Unless otherwise specified, all formats including alpha channels are assumed to be premultiplied.

premultiplied

whether the data is premultiplied

pub fn set_stride(&self, plane: u32, stride: u32)

Sets the stride for a plane.

The stride must be set for all planes before calling GLTextureBuilder::build().

plane

the plane to set the stride for

stride

the stride value

pub fn set_update_region(&self, region: Option<&Region>)

Sets the region to be updated by this texture. Together with update-texture this describes an update of a previous texture.

When rendering animations of large textures, it is possible that consecutive textures are only updating contents in parts of the texture. It is then possible to describe this update via these two properties, so that GTK can avoid rerendering parts that did not change.

An example would be a screen recording where only the mouse pointer moves.

region

the region to update

pub fn set_update_texture(&self, texture: Option<&impl IsA<Texture>>)

Sets the texture to be updated by this texture. See set_update_region() for an explanation.

texture

the texture to update

pub fn set_width(&self, width: u32)

Sets the width of the texture.

The width must be set before calling GLTextureBuilder::build().

width

The texture’s width or 0 to unset

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

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

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

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

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

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

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

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

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

impl DmabufTextureBuilder

pub unsafe fn build(self) -> Result<Texture, Error>

Builds a new Texture with the values set up in the builder.

It is a programming error to call this function if any mandatory property has not been set.

Not all formats defined in the drm_fourcc.h header are supported. You can use DisplayExt::dmabuf_formats() to get a list of supported formats. If the format is not supported by GTK, None will be returned and @error will be set.

The destroy function gets called when the returned texture gets released.

It is the responsibility of the caller to keep the file descriptors for the planes open until the created texture is no longer used, and close them afterwards (possibly using the @destroy notify).

It is possible to call this function multiple times to create multiple textures, possibly with changing properties in between.

Returns

a newly built Texture or NULL if the format is not supported

pub unsafe fn build_with_release_func<F: FnOnce() + Send + 'static>( self, release_func: F ) -> Result<Texture, Error>

Trait Implementations

impl Clone for DmabufTextureBuilder

fn clone(&self) -> Self

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for DmabufTextureBuilder

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for DmabufTextureBuilder

fn default() -> Self

Returns the “default value” for a type.

impl HasParamSpec for DmabufTextureBuilder

type ParamSpec = ParamSpecObject

type SetValue = DmabufTextureBuilder

Preferred value to be used as setter for the associated ParamSpec.

type BuilderFn = fn(_: &str) -> ParamSpecObjectBuilder<'_, DmabufTextureBuilder>

fn param_spec_builder() -> Self::BuilderFn

impl Hash for DmabufTextureBuilder

fn hash<H>(&self, state: &mut H)

where H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for DmabufTextureBuilder

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized + PartialOrd,

Restrict a value to a certain interval.

impl ParentClassIs for DmabufTextureBuilder

type Parent = Object

impl<OT: ObjectType> PartialEq<OT> for DmabufTextureBuilder

fn eq(&self, other: &OT) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<OT: ObjectType> PartialOrd<OT> for DmabufTextureBuilder

fn partial_cmp(&self, other: &OT) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl StaticType for DmabufTextureBuilder

fn static_type() -> Type

Returns the type identifier of Self.

impl Eq for DmabufTextureBuilder