DmabufTextureBuilder

gdk.dmabuf_texture_builder.DmabufTextureBuilder is a builder used to construct gdk.texture.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 gdk.dmabuf_texture_builder.DmabufTextureBuilder is quite simple: Create a texture builder, set all the necessary properties, and then call gdk.dmabuf_texture_builder.DmabufTextureBuilder.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

gdk.dmabuf_texture_builder.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

Constructors

this
this()

Creates a new texture builder.

Members

Functions

build
gdk.texture.Texture build(glib.types.DestroyNotify destroy, void* data)

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

getDisplay
gdk.display.Display getDisplay()

Returns the display that this texture builder is associated with.

getFd
int getFd(uint plane)

Gets the file descriptor for a plane.

getFourcc
uint getFourcc()

Gets the format previously set via gdk.dmabuf_texture_builder.DmabufTextureBuilder.setFourcc or 0 if the format wasn't set.

getHeight
uint getHeight()

Gets the height previously set via gdk.dmabuf_texture_builder.DmabufTextureBuilder.setHeight or 0 if the height wasn't set.

getModifier
ulong getModifier()

Gets the modifier value.

getNPlanes
uint getNPlanes()

Gets the number of planes.

getOffset
uint getOffset(uint plane)

Gets the offset value for a plane.

getPremultiplied
bool getPremultiplied()

Whether the data is premultiplied.

getStride
uint getStride(uint plane)

Gets the stride value for a plane.

getUpdateRegion
cairo.region.Region getUpdateRegion()

Gets the region previously set via gdk.dmabuf_texture_builder.DmabufTextureBuilder.setUpdateRegion or null if none was set.

getUpdateTexture
gdk.texture.Texture getUpdateTexture()

Gets the texture previously set via gdk.dmabuf_texture_builder.DmabufTextureBuilder.setUpdateTexture or null if none was set.

getWidth
uint getWidth()

Gets the width previously set via gdk.dmabuf_texture_builder.DmabufTextureBuilder.setWidth or 0 if the width wasn't set.

setDisplay
void setDisplay(gdk.display.Display display)

Sets the display that this texture builder is associated with.

setFd
void setFd(uint plane, int fd)

Sets the file descriptor for a plane.

setFourcc
void setFourcc(uint fourcc)

Sets the format of the texture.

setHeight
void setHeight(uint height)

Sets the height of the texture.

setModifier
void setModifier(ulong modifier)

Sets the modifier.

setNPlanes
void setNPlanes(uint nPlanes)

Sets the number of planes of the texture.

setOffset
void setOffset(uint plane, uint offset)

Sets the offset for a plane.

setPremultiplied
void setPremultiplied(bool premultiplied)

Sets whether the data is premultiplied.

setStride
void setStride(uint plane, uint stride)

Sets the stride for a plane.

setUpdateRegion
void setUpdateRegion(cairo.region.Region region)

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

setUpdateTexture
void setUpdateTexture(gdk.texture.Texture texture)

Sets the texture to be updated by this texture. See gdk.dmabuf_texture_builder.DmabufTextureBuilder.setUpdateRegion for an explanation.

setWidth
void setWidth(uint width)

Sets the width of the texture.

Inherited Members

From ObjectG

setGObject
void setGObject(void* cObj, Flag!"Take" take)

Set the GObject of a D ObjectG wrapper.

cPtr
void* cPtr(Flag!"Dup" dup)

Get a pointer to the underlying C object.

ref_
void* ref_(void* gObj)

Calls g_object_ref() on a GObject.

unref
unref(void* gObj)

Calls g_object_unref() on a GObject.

getType
GType getType()

Get the GType of an object.

gType
GType gType [@property getter]

GObject GType property.

self
ObjectG self()

Convenience method to return this cast to a type. For use in D with statements.

getDObject
T getDObject(void* cptr, Flag!"Take" take)

Template to get the D object from a C GObject and cast it to the given D object type.

connectSignalClosure
ulong connectSignalClosure(string signalDetail, DClosure closure, Flag!"After" after)

Connect a D closure to an object signal.

setProperty
void setProperty(string propertyName, T val)

Template for setting a GObject property.

getProperty
T getProperty(string propertyName)

Template for getting a GObject property.

compatControl
size_t compatControl(size_t what, void* data)
bindProperty
gobject.binding.Binding bindProperty(string sourceProperty, gobject.object.ObjectG target, string targetProperty, gobject.types.BindingFlags flags)

Creates a binding between source_property on source and target_property on target.

bindPropertyFull
gobject.binding.Binding bindPropertyFull(string sourceProperty, gobject.object.ObjectG target, string targetProperty, gobject.types.BindingFlags flags, gobject.closure.Closure transformTo, gobject.closure.Closure transformFrom)

Creates a binding between source_property on source and target_property on target, allowing you to set the transformation functions to be used by the binding.

forceFloating
void forceFloating()

This function is intended for #GObject implementations to re-enforce a floating[floating-ref] object reference. Doing this is seldom required: all #GInitiallyUnowneds are created with a floating reference which usually just needs to be sunken by calling gobject.object.ObjectG.refSink.

freezeNotify
void freezeNotify()

Increases the freeze count on object. If the freeze count is non-zero, the emission of "notify" signals on object is stopped. The signals are queued until the freeze count is decreased to zero. Duplicate notifications are squashed so that at most one #GObject::notify signal is emitted for each property modified while the object is frozen.

getData
void* getData(string key)

Gets a named field from the objects table of associations (see gobject.object.ObjectG.setData).

getProperty
void getProperty(string propertyName, gobject.value.Value value)

Gets a property of an object.

getQdata
void* getQdata(glib.types.Quark quark)

This function gets back user data pointers stored via gobject.object.ObjectG.setQdata.

getv
void getv(string[] names, gobject.value.Value[] values)

Gets n_properties properties for an object. Obtained properties will be set to values. All properties must be valid. Warnings will be emitted and undefined behaviour may result if invalid properties are passed in.

isFloating
bool isFloating()

Checks whether object has a floating[floating-ref] reference.

notify
void notify(string propertyName)

Emits a "notify" signal for the property property_name on object.

notifyByPspec
void notifyByPspec(gobject.param_spec.ParamSpec pspec)

Emits a "notify" signal for the property specified by pspec on object.

refSink
gobject.object.ObjectG refSink()

Increase the reference count of object, and possibly remove the floating[floating-ref] reference, if object has a floating reference.

runDispose
void runDispose()

Releases all references to other objects. This can be used to break reference cycles.

setData
void setData(string key, void* data)

Each object carries around a table of associations from strings to pointers. This function lets you set an association.

setProperty
void setProperty(string propertyName, gobject.value.Value value)

Sets a property on an object.

stealData
void* stealData(string key)

Remove a specified datum from the object's data associations, without invoking the association's destroy handler.

stealQdata
void* stealQdata(glib.types.Quark quark)

This function gets back user data pointers stored via gobject.object.ObjectG.setQdata and removes the data from object without invoking its destroy() function (if any was set). Usually, calling this function is only required to update user data pointers with a destroy notifier, for example:

thawNotify
void thawNotify()

Reverts the effect of a previous call to gobject.object.ObjectG.freezeNotify. The freeze count is decreased on object and when it reaches zero, queued "notify" signals are emitted.

watchClosure
void watchClosure(gobject.closure.Closure closure)

This function essentially limits the life time of the closure to the life time of the object. That is, when the object is finalized, the closure is invalidated by calling gobject.closure.Closure.invalidate on it, in order to prevent invocations of the closure with a finalized (nonexisting) object. Also, gobject.object.ObjectG.ref_ and gobject.object.ObjectG.unref are added as marshal guards to the closure, to ensure that an extra reference count is held on object during invocation of the closure. Usually, this function will be called on closures that use this object as closure data.

connectNotify
ulong connectNotify(string detail, T callback, Flag!"After" after)

Connect to Notify signal.