class GdkPixbuf::PixbufModule

• GdkPixbuf::PixbufModule
• Reference
• Object

Overview

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

If Gdk::Pixbuf 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 Gdk::Pixbuf 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 Gdk::Pixbuf API. To underline this fact, they are protected by the GDK_PIXBUF_ENABLE_BACKEND pre-processor symbol.

Each loadable module must contain a Gdk::PixbufModuleFillVtableFunc function named fill_vtable, which will get called when the module is loaded and must set the function pointers of the Gdk::PixbufModule.

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 Gdk::Pixbuf to obtain the list of available loaders and their signatures.

Modules may only implement a subset of the functionality available via Gdk::PixbufModule. If a particular functionality is not implemented, the fill_vtable function will simply not set the corresponding function pointers of the Gdk::PixbufModule 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 Gdk::Pixbuf 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)

Defined in:

lib/gi-crystal/src/auto/gdk_pixbuf-2.0/pixbuf_module.cr

Constructors

• .new(pointer : Pointer(Void), transfer : GICrystal::Transfer)
• .new(data : LibGdkPixbuf::PixbufModule, transfer : GICrystal::Transfer)
• .new(load : GdkPixbuf::PixbufModuleLoadFunc | Nil = nil, load_xpm_data : GdkPixbuf::PixbufModuleLoadXpmDataFunc | Nil = nil, stop_load : GdkPixbuf::PixbufModuleStopLoadFunc | Nil = nil, load_increment : GdkPixbuf::PixbufModuleIncrementLoadFunc | Nil = nil, load_animation : GdkPixbuf::PixbufModuleLoadAnimationFunc | Nil = nil, save : GdkPixbuf::PixbufModuleSaveFunc | Nil = nil, is_save_option_supported : GdkPixbuf::PixbufModuleSaveOptionSupportedFunc | Nil = nil)

Instance Method Summary

• #==(other : self) : Bool

  Returns true if this reference is the same as other.

• #_reserved1 : Pointer(Void) | Nil
• #_reserved1!
• #_reserved2 : Pointer(Void) | Nil
• #_reserved2!
• #_reserved3 : Pointer(Void) | Nil
• #_reserved3!
• #_reserved4 : Pointer(Void) | Nil
• #_reserved4!
• #begin_load : Pointer(Void) | Nil
• #begin_load!
• #info : GdkPixbuf::PixbufFormat | Nil
• #info!
• #is_save_option_supported : GdkPixbuf::PixbufModuleSaveOptionSupportedFunc
• #is_save_option_supported=(value : GdkPixbuf::PixbufModuleSaveOptionSupportedFunc)
• #load : GdkPixbuf::PixbufModuleLoadFunc
• #load=(value : GdkPixbuf::PixbufModuleLoadFunc)
• #load_animation : GdkPixbuf::PixbufModuleLoadAnimationFunc
• #load_animation=(value : GdkPixbuf::PixbufModuleLoadAnimationFunc)
• #load_increment : GdkPixbuf::PixbufModuleIncrementLoadFunc
• #load_increment=(value : GdkPixbuf::PixbufModuleIncrementLoadFunc)
• #load_xpm_data : GdkPixbuf::PixbufModuleLoadXpmDataFunc
• #load_xpm_data=(value : GdkPixbuf::PixbufModuleLoadXpmDataFunc)
• #module : GModule::Module | Nil
• #module!
• #module_name : String | Nil
• #module_name!
• #module_path : String | Nil
• #module_path!
• #save : GdkPixbuf::PixbufModuleSaveFunc
• #save=(value : GdkPixbuf::PixbufModuleSaveFunc)
• #save_to_callback : Pointer(Void) | Nil
• #save_to_callback!
• #stop_load : GdkPixbuf::PixbufModuleStopLoadFunc
• #stop_load=(value : GdkPixbuf::PixbufModuleStopLoadFunc)
• #to_unsafe

Constructor Detail

Instance Method Detail