Cogl-18 ▶ Cogl ▶ Texture2D

Explicitly allocates the storage for the given texture which allows you to be sure that there is enough memory for the texture and if not then the error can be handled gracefully.

Normally applications don't need to use this api directly since the texture will be implicitly allocated when data is set on the texture, or if the texture is attached to a Cogl.Offscreen framebuffer and rendered too.

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

Whenever the source_property is changed the target_property is updated using the same value. For instance:

  g_object_bind_property (action, "active", widget, "sensitive", 0);
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Will result in the "sensitive" property of the widget GObject.Object instance to be updated with the same value of the "active" property of the action GObject.Object instance.

If flags contains GObject.BindingFlags.BIDIRECTIONAL then the binding will be mutual: if target_property on target changes then the source_property on source will be updated as well.

The binding will automatically be removed when either the source or the target instances are finalized. To remove the binding without affecting the source and the target you can just call g_object_unref() on the returned GObject.Binding instance.

Removing the binding by calling g_object_unref() on it must only be done if the binding, source and target are only used from a single thread and it is clear that both source and target outlive the binding. Especially it is not safe to rely on this if the binding, source or target can be finalized from different threads. Keep another reference to the binding and use g_binding_unbind() instead to be on the safe side.

A GObject.Object can have multiple bindings.

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.

This function is the language bindings friendly version of g_object_bind_property_full(), using GClosures instead of function pointers.

Blocks a handler of an instance so it will not be called during any signal emissions

Disconnects a handler from an instance so it will not be called during any future or currently ongoing emissions of the signal it has been connected to.

This function is intended for GObject.Object 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 g_object_ref_sink().

Allows you to manually iterate the low-level textures that define a given region of a high-level Cogl.Texture.

For example cogl_texture_2d_sliced_new_with_size() can be used to create a meta texture that may slice a large image into multiple, smaller power-of-two sized textures. These high level textures are not directly understood by a GPU and so this API must be used to manually resolve the underlying textures for drawing.

All high level textures (Cogl.AtlasTexture, Cogl.SubTexture and Cogl.Texture2DSliced) can be handled consistently using this interface which greately simplifies implementing primitives that support all texture types.

For example if you use the cogl_rectangle() API then Cogl will internally use this API to resolve the low level textures of any meta textures you have associated with CoglPipeline layers.

The low level drawing APIs such as cogl_primitive_draw() don't understand the Cogl.Texture interface and so it is your responsibility to use this API to resolve all CoglPipeline textures into low-level textures before drawing.

For each low-level texture that makes up part of the given region of the meta_texture, callback is called specifying how the low-level texture maps to the original region.

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.Object::notify signal is emitted for each property modified while the object is frozen.

This is necessary for accessors that modify multiple properties to prevent premature notification while the object is still being modified.

Queries what components the given texture stores internally as set via cogl_texture_set_components().

For textures created by the ‘_with_size’ constructors the default is Cogl.TextureComponents.RGBA. The other constructors which take a %CoglBitmap or a data pointer default to the same components as the pixel format of the data.

Copies the pixel data from a cogl texture to system memory.

Don't pass the value of cogl_texture_get_rowstride() as the rowstride argument, the rowstride should be the rowstride you want for the destination data buffer not the rowstride of the source texture

Queries the GL handles for a GPU side texture through its Cogl.Texture.

If the texture is spliced the data for the first sub texture will be queried.

Queries the height of a cogl texture.

Queries the pre-multiplied alpha status for internally stored red, green and blue components for the given texture as set by cogl_texture_set_premultiplied().

By default the pre-multiplied state is TRUE.

Gets a property of an object.

The value can be:

• an empty GObject.Value initialized by G_VALUE_INIT, which will be automatically initialized with the expected type of the property (since GLib 2.60)
• a GObject.Value initialized with the expected type of the property
• a GObject.Value initialized with a type to which the expected type of the property can be transformed

In general, a copy is made of the property contents and the caller is responsible for freeing the memory by calling GObject.Value.unset.

Note that GObject.Object.get_property is really intended for language bindings, GObject.Object.get is much more convenient for C programming.

This function gets back user data pointers stored via g_object_set_qdata().

Queries the width of a cogl texture.

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.

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

Queries if a texture is sliced (stored as multiple GPU side tecture objects).

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

When possible, eg. when signaling a property change from within the class that registered the property, you should use g_object_notify_by_pspec() instead.

Note that emission of the notify signal may be blocked with g_object_freeze_notify(). In this case, the signal emissions are queued and will be emitted (in reverse order) when g_object_thaw_notify() is called.

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

This function omits the property name lookup, hence it is faster than g_object_notify().

One way to avoid using g_object_notify() from within the class that registered the properties, and using g_object_notify_by_pspec() instead, is to store the GParamSpec used with g_object_class_install_property() inside a static array, e.g.:

  typedef enum
  {
    PROP_FOO = 1,
    PROP_LAST
  } MyObjectProperty;

  static GParamSpec *properties[PROP_LAST];

  static void
  my_object_class_init (MyObjectClass *klass)
  {
    properties[PROP_FOO] = g_param_spec_int ("foo", NULL, NULL,
                                             0, 100,
                                             50,
                                             G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS);
    g_object_class_install_property (gobject_class,
                                     PROP_FOO,
                                     properties[PROP_FOO]);
  }
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and then notify a change on the "foo" property with:

  g_object_notify_by_pspec (self, properties[PROP_FOO]);
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Increases the reference count of object.

Since GLib 2.56, if GLIB_VERSION_MAX_ALLOWED is 2.56 or greater, the type of object will be propagated to the return type (using the GCC typeof() extension), so any casting the caller needs to do on the return type must be explicit.

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

In other words, if the object is floating, then this call "assumes ownership" of the floating reference, converting it to a normal reference by clearing the floating flag while leaving the reference count unchanged. If the object is not floating, then this call adds a new normal reference increasing the reference count by one.

Since GLib 2.56, the type of object will be propagated to the return type under the same conditions as for g_object_ref().

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

This function should only be called from object system implementations.

Sets multiple properties of an object at once. The properties argument should be a dictionary mapping property names to values.

Affects the internal storage format for this texture by specifying what components will be required for sampling later.

This api affects how data is uploaded to the GPU since unused components can potentially be discarded from source data.

For textures created by the ‘_with_size’ constructors the default is Cogl.TextureComponents.RGBA. The other constructors which take a %CoglBitmap or a data pointer default to the same components as the pixel format of the data.

Note that the Cogl.TextureComponents.RG format is not available on all drivers. The availability can be determined by checking for the Cogl.FeatureID.OGL_FEATURE_ID_TEXTURE_RG feature. If this format is used on a driver where it is not available then Cogl.TextureError.FORMAT will be raised when the texture is allocated. Even if the feature is not available then Cogl.PixelFormat.RG_88 can still be used as an image format as long as Cogl.TextureComponents.RG isn't used as the texture's components.

texture a Cogl.Texture. Sets all the pixels for a given mipmap level by copying the pixel data pointed to by the data argument into the given texture.

data should point to the first pixel to copy corresponding to the top left of the mipmap level being set.

If rowstride equals 0 then it will be automatically calculated from the width of the mipmap level and the bytes-per-pixel for the given format.

A mipmap level of 0 corresponds to the largest, base image of a texture and level 1 is half the width and height of level 0. If dividing any dimension of the previous level by two results in a fraction then round the number down (floor()), but clamp to 1 something like this:

 next_width = MAX (1, floor (prev_width));
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You can determine the number of mipmap levels for a given texture like this:

 n_levels = 1 + floor (log2 (max_dimension));
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Where %max_dimension is the larger of cogl_texture_get_width() and cogl_texture_get_height().

It is an error to pass a level number >= the number of levels that texture can have according to the above calculation.

Since the storage for a Cogl.Texture is allocated lazily then if the given texture has not previously been allocated then this api can return false and throw an exceptional error if there is not enough memory to allocate storage for texture.

Affects the internal storage format for this texture by specifying whether red, green and blue color components should be stored as pre-multiplied alpha values.

This api affects how data is uploaded to the GPU since Cogl will convert source data to have premultiplied or unpremultiplied components according to this state.

For example if you create a texture via cogl_texture_2d_new_with_size() and then upload data via cogl_texture_set_data() passing a source format of Cogl.PixelFormat.RGBA_8888 then Cogl will internally multiply the red, green and blue components of the source data by the alpha component, for each pixel so that the internally stored data has pre-multiplied alpha components. If you instead upload data that already has pre-multiplied components by passing Cogl.PixelFormat.RGBA_8888_PRE as the source format to cogl_texture_set_data() then the data can be uploaded without being converted.

By default the premultipled state is TRUE.

Sets a property on an object.

Sets the pixels in a rectangular subregion of texture from an in-memory buffer containing pixel data.

The region set can't be larger than the source data

Copies a specified source region from bitmap to the position (src_x, src_y) of the given destination texture handle.

The region updated can't be larger than the source bitmap

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

This function gets back user data pointers stored via g_object_set_qdata() 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:

void
object_add_to_user_list (GObject     *object,
                         const gchar *new_string)
{
  // the quark, naming the object data
  GQuark quark_string_list = g_quark_from_static_string ("my-string-list");
  // retrieve the old string list
  GList *list = g_object_steal_qdata (object, quark_string_list);

  // prepend new string
  list = g_list_prepend (list, g_strdup (new_string));
  // this changed 'list', so we need to set it again
  g_object_set_qdata_full (object, quark_string_list, list, free_string_list);
}
static void
free_string_list (gpointer data)
{
  GList *node, *list = data;

  for (node = list; node; node = node->next)
    g_free (node->data);
  g_list_free (list);
}
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Using g_object_get_qdata() in the above example, instead of g_object_steal_qdata() would have left the destroy function set, and thus the partial string list would have been freed upon g_object_set_qdata_full().

Stops a signal's emission by the given signal name. This will prevent the default handler and any subsequent signal handlers from being invoked.

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

Duplicate notifications for each property are squashed so that at most one GObject.Object::notify signal is emitted for each property, in the reverse order in which they have been queued.

It is an error to call this function when the freeze count is zero.

Unblocks a handler so it will be called again during any signal emissions

Decreases the reference count of object. When its reference count drops to 0, the object is finalized (i.e. its memory is freed).

If the pointer to the GObject.Object may be reused in future (for example, if it is an instance variable of another object), it is recommended to clear the pointer to null rather than retain a dangling pointer to a potentially invalid GObject.Object instance. Use g_clear_object() for this.

the constructed function is called by g_object_new() as the final step of the object creation process. At the point of the call, all construction properties have been set on the object. The purpose of this call is to allow for object initialisation steps that can only be performed after construction properties have been set. constructed implementors should chain up to the constructed call of their parent class to allow it to complete its initialisation.

emits property change notification for a bunch of properties. Overriding dispatch_properties_changed should be rarely needed.

the dispose function is supposed to drop all references to other objects, but keep the instance otherwise intact, so that client method invocations still work. It may be run multiple times (due to reference loops). Before returning, dispose should chain up to the dispose method of the parent class.

instance finalization function, should finish the finalization of the instance begun in dispose and chain up to the finalize method of the parent class.

the generic getter for all properties of this type. Should be overridden for every type with properties.

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

When possible, eg. when signaling a property change from within the class that registered the property, you should use g_object_notify_by_pspec() instead.

Note that emission of the notify signal may be blocked with g_object_freeze_notify(). In this case, the signal emissions are queued and will be emitted (in reverse order) when g_object_thaw_notify() is called.

the generic setter for all properties of this type. Should be overridden for every type with properties. If implementations of set_property don't emit property change notification explicitly, this will be done implicitly by the type system. However, if the notify signal is emitted explicitly, the type system will not emit it a second time.

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 g_closure_invalidate() on it, in order to prevent invocations of the closure with a finalized (nonexisting) object. Also, g_object_ref() and g_object_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.

Find the GObject.ParamSpec with the given name for an interface. Generally, the interface vtable passed in as g_iface will be the default vtable from g_type_default_interface_ref(), or, if you know the interface has already been loaded, g_type_default_interface_peek().

Add a property to an interface; this is only useful for interfaces that are added to GObject-derived types. Adding a property to an interface forces all objects classes with that interface to have a compatible property. The compatible property could be a newly created GObject.ParamSpec, but normally g_object_class_override_property() will be used so that the object class only needs to provide an implementation and inherits the property description, default value, bounds, and so forth from the interface property.

This function is meant to be called from the interface's default vtable initialization function (the class_init member of GObject.TypeInfo.) It must not be called after after class_init has been called for any object types implementing this interface.

If pspec is a floating reference, it will be consumed.

Lists the properties of an interface.Generally, the interface vtable passed in as g_iface will be the default vtable from g_type_default_interface_ref(), or, if you know the interface has already been loaded, g_type_default_interface_peek().