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

The Linux kernel documentation
The header file drm_fourcc.h

class DmabufTextureBuilder : ObjectG {

this();

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

gdk.display.Display getDisplay();

int getFd(uint plane);

uint getFourcc();

uint getHeight();

ulong getModifier();

uint getNPlanes();

uint getOffset(uint plane);

bool getPremultiplied();

uint getStride(uint plane);

cairo.region.Region getUpdateRegion();

gdk.texture.Texture getUpdateTexture();

uint getWidth();

void setDisplay(gdk.display.Display display);

void setFd(uint plane, int fd);

void setFourcc(uint fourcc);

void setHeight(uint height);

void setModifier(ulong modifier);

void setNPlanes(uint nPlanes);

void setOffset(uint plane, uint offset);

void setPremultiplied(bool premultiplied);

void setStride(uint plane, uint stride);

void setUpdateRegion(cairo.region.Region region);

void setUpdateTexture(gdk.texture.Texture texture);

void setWidth(uint width);

}

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.

gdk dmabuf_texture_builder classes