PixbufModule

open class PixbufModule : PixbufModuleProtocol

A GdkPixbufModule contains the necessary functions to load and save images in a certain file format.

If GdkPixbuf has been compiled with GModule support, it can be extended by modules which can load (and perhaps also save) new image and animation formats.

Implementing modules

The GdkPixbuf interfaces needed for implementing modules are contained in gdk-pixbuf-io.h (and gdk-pixbuf-animation.h if the module supports animations). They are not covered by the same stability guarantees as the regular GdkPixbuf API. To underline this fact, they are protected by the GDK_PIXBUF_ENABLE_BACKEND pre-processor symbol.

Each loadable module must contain a GdkPixbufModuleFillVtableFunc function named fill_vtable, which will get called when the module is loaded and must set the function pointers of the GdkPixbufModule.

In order to make format-checking work before actually loading the modules (which may require calling dlopen to load image libraries), modules export their signatures (and other information) via the fill_info function. An external utility, gdk-pixbuf-query-loaders, uses this to create a text file containing a list of all available loaders and their signatures. This file is then read at runtime by GdkPixbuf to obtain the list of available loaders and their signatures.

Modules may only implement a subset of the functionality available via GdkPixbufModule. If a particular functionality is not implemented, the fill_vtable function will simply not set the corresponding function pointers of the GdkPixbufModule structure. If a module supports incremental loading (i.e. provides begin_load, stop_load and load_increment), it doesn’t have to implement load, since GdkPixbuf can supply a generic load implementation wrapping the incremental loading.

Installing modules

Installing a module is a two-step process:

  • copy the module file(s) to the loader directory (normally $libdir/gdk-pixbuf-2.0/$version/loaders, unless overridden by the environment variable GDK_PIXBUF_MODULEDIR)
  • call gdk-pixbuf-query-loaders to update the module file (normally $libdir/gdk-pixbuf-2.0/$version/loaders.cache, unless overridden by the environment variable GDK_PIXBUF_MODULE_FILE)

The PixbufModule type acts as an owner of an underlying GdkPixbufModule instance. It provides the methods that can operate on this data type through PixbufModuleProtocol conformance. Use PixbufModule as a strong reference or owner of a GdkPixbufModule instance.

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  • ptr 
    Untyped pointer to the underlying `GdkPixbufModule` instance.

    For type-safe access, use the generated, typed pointer _ptr property instead.

    Declaration

    Swift

    public let ptr: UnsafeMutableRawPointer!
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  • Designated initialiser from the underlying C data type. This creates an instance without performing an unbalanced retain i.e., ownership is transferred to the PixbufModule instance.

    Declaration

    Swift

    @inlinable
public init(_ op: UnsafeMutablePointer<GdkPixbufModule>)

    Parameters

    op

    pointer to the underlying object
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  • Designated initialiser from a constant pointer to the underlying C data type. This creates an instance without performing an unbalanced retain i.e., ownership is transferred to the PixbufModule instance.

    Declaration

    Swift

    @inlinable
public init(_ op: UnsafePointer<GdkPixbufModule>)

    Parameters

    op

    pointer to the underlying object
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  • Optional initialiser from a non-mutating gpointer to the underlying C data type. This creates an instance without performing an unbalanced retain i.e., ownership is transferred to the PixbufModule instance.

    Declaration

    Swift

    @inlinable
public init!(gpointer op: gpointer?)

    Parameters

    op

    gpointer to the underlying object
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  • Optional initialiser from a non-mutating gconstpointer to the underlying C data type. This creates an instance without performing an unbalanced retain i.e., ownership is transferred to the PixbufModule instance.

    Declaration

    Swift

    @inlinable
public init!(gconstpointer op: gconstpointer?)

    Parameters

    op

    pointer to the underlying object
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  • Optional initialiser from a constant pointer to the underlying C data type. This creates an instance without performing an unbalanced retain i.e., ownership is transferred to the PixbufModule instance.

    Declaration

    Swift

    @inlinable
public init!(_ op: UnsafePointer<GdkPixbufModule>?)

    Parameters

    op

    pointer to the underlying object
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  • Optional initialiser from the underlying C data type. This creates an instance without performing an unbalanced retain i.e., ownership is transferred to the PixbufModule instance.

    Declaration

    Swift

    @inlinable
public init!(_ op: UnsafeMutablePointer<GdkPixbufModule>?)

    Parameters

    op

    pointer to the underlying object
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  • Designated initialiser from the underlying C data type. GdkPixbufModule does not allow reference counting, so despite the name no actual retaining will occur. i.e., ownership is transferred to the PixbufModule instance.

    Declaration

    Swift

    @inlinable
public init(retaining op: UnsafeMutablePointer<GdkPixbufModule>)

    Parameters

    op

    pointer to the underlying object
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  • Reference intialiser for a related type that implements PixbufModuleProtocol GdkPixbufModule does not allow reference counting.

    Declaration

    Swift

    @inlinable
public init<T>(_ other: T) where T : PixbufModuleProtocol

    Parameters

    other

    an instance of a related type that implements PixbufModuleProtocol
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  • Unsafe typed initialiser. Do not use unless you know the underlying data type the pointer points to conforms to PixbufModuleProtocol.

    Declaration

    Swift

    @inlinable
public init<T>(cPointer p: UnsafeMutablePointer<T>)

    Parameters

    cPointer

    pointer to the underlying object
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  • Unsafe typed, retaining initialiser. Do not use unless you know the underlying data type the pointer points to conforms to PixbufModuleProtocol.

    Declaration

    Swift

    @inlinable
public init<T>(retainingCPointer cPointer: UnsafeMutablePointer<T>)

    Parameters

    cPointer

    pointer to the underlying object
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  • Unsafe untyped initialiser. Do not use unless you know the underlying data type the pointer points to conforms to PixbufModuleProtocol.

    Declaration

    Swift

    @inlinable
public init(raw p: UnsafeRawPointer)

    Parameters

    p

    raw pointer to the underlying object
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  • Unsafe untyped, retaining initialiser. Do not use unless you know the underlying data type the pointer points to conforms to PixbufModuleProtocol.

    Declaration

    Swift

    @inlinable
public init(retainingRaw raw: UnsafeRawPointer)
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  • Unsafe untyped initialiser. Do not use unless you know the underlying data type the pointer points to conforms to PixbufModuleProtocol.

    Declaration

    Swift

    @inlinable
public required init(raw p: UnsafeMutableRawPointer)

    Parameters

    p

    mutable raw pointer to the underlying object
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  • Unsafe untyped, retaining initialiser. Do not use unless you know the underlying data type the pointer points to conforms to PixbufModuleProtocol.

    Declaration

    Swift

    @inlinable
public init(retainingRaw raw: UnsafeMutableRawPointer)

    Parameters

    raw

    mutable raw pointer to the underlying object
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  • Unsafe untyped initialiser. Do not use unless you know the underlying data type the pointer points to conforms to PixbufModuleProtocol.

    Declaration

    Swift

    @inlinable
public init(opaquePointer p: OpaquePointer)

    Parameters

    p

    opaque pointer to the underlying object
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  • Unsafe untyped, retaining initialiser. Do not use unless you know the underlying data type the pointer points to conforms to PixbufModuleProtocol.

    Declaration

    Swift

    @inlinable
public init(retainingOpaquePointer p: OpaquePointer)

    Parameters

    p

    opaque pointer to the underlying object
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