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# Xfc::Gtk::IconTheme Class Reference

A GtkIconTheme C++ wrapper class. More...

`#include <xfc/gtk/icontheme.hh>`

Inheritance diagram for Xfc::Gtk::IconTheme:

List of all members.

## Signal Prototypes

- const ChangedSignalType changed_signal
    Changed signal (see signal_changed()).

## Public Member Functions

Constructors

- IconTheme ()
    Constructs a new icon theme object with a reference count of 1 that the caller owns.
- virtual ~IconTheme ()
    Destructor.

Accessors

- GtkIconTheme * gtk_icon_theme () const
    Get a pointer to the GtkIconTheme structure.
- operator GtkIconTheme * () const
    Conversion operator; safely converts an IconTheme to a GtkIconTheme pointer.
- std::vector< String > get_search_path () const
    Gets the current search path (see set_search_path()).
- String get_example_icon_name () const
    Gets the name of an icon that is representative of the current theme (for instance, to use when presenting a list of themes to the user).
- bool has_icon (const String &icon_name) const
    Checks whether an icon theme includes an icon for a particular name.
- std::vector< int > get_icon_sizes (const String &icon_name) const
    Returns a vector of integers describing the sizes at which the icon is available without scaling.

Methods

- void set_screen (Gdk::Screen *screen)
    Sets the screen for an icon theme.
- void set_search_path (const std::vector< String > &path)
    Sets the search path for the icon theme object.
- void append_search_path (const String &path)
    Appends a directory to the search path (see set_search_path()).
- void prepend_search_path (const String &path)
    Prepends a directory to the search path (see set_search_path()).
- void set_custom_theme (const String &theme_name)
    Sets the name of the icon theme that the IconTheme object uses, overriding system configuration.
- Pointer< IconInfo > lookup_icon (const String &icon_name, int size, IconLookupFlagsField flags)
    Looks up a named icon and returns a structure containing information such as the filename of the icon.
- Pointer< Gdk::Pixbuf > load_icon (const String &icon_name, int size, IconLookupFlagsField flags, G::Error *error=0)
    Looks up an icon in an icon theme, scales it to the given size and renders it into a pixbuf.
- std::vector< String > list_icons (const String &context)
    Lists the icons in the current icon theme.
- bool rescan_if_needed ()
    Checks to see if the icon theme has changed; if it has, any currently cached information is discarded and will be reloaded next time the icon theme is accessed.

Signal Proxies

- const ChangedSignalProxy signal_changed ()
    Connect to the changed_signal; emitted when the current icon theme is switched or GTK+ detects that a change has occurred in the contents of the current icon theme.

## Static Public Member Functions

Accessors

- IconTheme * get_for_screen (const Gdk::Screen *screen=0)
    Gets the icon theme object associated with screen.

Methods

- void add_builtin_icon (const String &icon_name, int size, Gdk::Pixbuf &pixbuf)
    Registers a built-in icon for icon theme lookups.

## Protected Member Functions

Constructors

- IconTheme (GtkIconTheme *icon_theme, bool owns_reference=true)
    Construct a new IconTheme from an existing GtkIconTheme.

## Detailed Description

A GtkIconTheme C++ wrapper class.

IconTheme acts as a database of information about an icon theme. Normally, you retrieve the icon theme for a particular screen using Gtk::IconTeme::get_for_screen() and it will contain information about current icon theme for that screen, but you can also create a new IconTheme object and set the icon theme name explicitely using Gtk::IconTheme::set_custom_theme().

IconTheme provides a facility for looking up icons by name and size. The main reason for using a name rather than simply providing a filename is to allow different icons to be used depending on what icon theme is seleceted by the user. The operation of icon themes on Linux and Unix follows the Icon Theme Specification. There is a default icon theme, named hicolor where applications should install their icons, but more additional application themes can be installed as operating system vendors and users choose.

Named icons are similar to the Themeable Stock Images, and the distinction between the two may be a bit confusing. A few things to keep in mind: Stock images usually are used in conjunction with stock items, such as Gtk::StockId::OK or Gtk::StockId::OPEN. Named icons are easier to set up and therefore are more useful for new icons that an application wants to add, such as application icons or window icons.

Stock images can only be loaded at the symbolic sizes defined by the Gtk::IconSize enumeration, or by custom sizes defined by Gtk::icon_size_register(), while named icons are more flexible and any pixel size can be specified. Because stock images are closely tied to stock items, and thus to actions in the user interface, stock images may come in multiple variants for different widget states or writing directions.

A good rule of thumb is that if there is a stock image for what you want to use, use it, otherwise use a named icon. It turns out that internally stock images are generally defined in terms of one or more named icons. (An example of the more than one case is icons that depend on writing direction; Gtk::StockId::GO_FORWARD uses the two themed icons "gtk-stock-go-forward-ltr" and "gtk-stock-go-forward-rtl".)

In many cases, named themes are used indirectly, via Gtk::Image or stock items, rather than directly, but looking up icons directly is also simple. The IconTheme object acts as a database of all the icons in the current theme. You can create new IconTheme objects, but its much more efficient to use the standard icon theme for the Gdk::Screen so that the icon information is shared with other people looking up icons. In the case where the default screen is being used, looking up an icon can be as simple as:

        G::Error error;
        Gtk::IconTheme *icon_theme = Gtk::IconTheme::get_for_screen();
        Pointer<Gdk::Pixbuf> pixbuf = icon_theme->load_icon("my-icon-name", 48, 0, &error);

        if (!pixbuf)
        {
            g_warning("Couldn't load icon: %s", error.message());
        }
        else
        {
            // Use the pixbuf
        }

## Constructor & Destructor Documentation

Xfc::Gtk::IconTheme::IconTheme | ( | GtkIconTheme * | icon_theme,
|  | bool | owns_reference = `true`
| ) | `[explicit, protected]`

  | Construct a new IconTheme from an existing GtkIconTheme. Parameters:
  | icon_theme | A pointer to a GtkIconTheme.
  | owns_reference | Set false if the initial reference count is floating, set true if it's not.
The icon_theme can be a newly created GtkIconTheme or an existing GtkIconTheme (see G::Object::Object).

Xfc::Gtk::IconTheme::IconTheme | ( |  | ) |

| Constructs a new icon theme object with a reference count of 1 that the caller owns. Icon theme objects are used to lookup up an icon by name in a particular icon theme Usually, you'll want to use get_for_screen() rather than creating a new icon theme object for scratch.

## Member Function Documentation

void Xfc::Gtk::IconTheme::add_builtin_icon | ( | const String & | icon_name,
|  | int | size,
|  | Gdk::Pixbuf & | pixbuf
| ) | `[static]`

  | Registers a built-in icon for icon theme lookups. Parameters:
  | icon_name | The name of the icon to register.
  | size | The size at which to register the icon.
  | pixbuf | A Gdk::Pixbuf that contains the image to use for icon_name.
The idea of built-in icons is to allow an application or library that uses themed icons to function requiring files to be present in the file system. For instance, the default images for all of GTK+'s stock icons are registered as built-in icons. In general, if you use add_builtin_icon() you should also install the icon in the icon theme, so that the icon is generally available. Note different images can be registered for the same icon name at different sizes. This method will generally be used with pixbufs loaded inline (see Gdk::Pixbuf::create(int, const unsigned char*, bool, G::Error*));

void Xfc::Gtk::IconTheme::append_search_path | ( | const String & | path | ) |

  | Appends a directory to the search path (see set_search_path()). Parameters:
  | path | The directory name to append to the icon path.

String Xfc::Gtk::IconTheme::get_example_icon_name | ( |  | ) | const

| Gets the name of an icon that is representative of the current theme (for instance, to use when presenting a list of themes to the user). Returns: The name of an example icon or null.

IconTheme* Xfc::Gtk::IconTheme::get_for_screen | ( | const Gdk::Screen * | screen = `0` | ) | `[static]`

  | Gets the icon theme object associated with screen. Parameters:
  | screen | A Gdk::Screen, or null for the default screen.
Returns: A unique IconTheme associated with the given screen. If screen is null the icon theme for the default screen is returned. The icon theme is associated with the screen and can be used as long as the screen is open. If this method has not previously been called for the given screen, a new icon theme object will be created and associated with the screen. Icon theme objects are fairly expensive to create, so using this method is usually a better choice than constructing a new icon theme object and setting the screen yourself. By using this method a single icon theme object will be shared between users.

std::vector<int> Xfc::Gtk::IconTheme::get_icon_sizes | ( | const String & | icon_name | ) | const

  | Returns a vector of integers describing the sizes at which the icon is available without scaling. Parameters:
  | icon_name | The name of an icon.
Returns: A vector of int describing the sizes at which the icon is available. A size of -1 means that the icon is available in a scalable format.

std::vector<String> Xfc::Gtk::IconTheme::get_search_path | ( |  | ) | const

| Gets the current search path (see set_search_path()). Returns: A list of icon theme path directories.

bool Xfc::Gtk::IconTheme::has_icon | ( | const String & | icon_name | ) | const

  | Checks whether an icon theme includes an icon for a particular name. Parameters:
  | icon_name | The name of an icon.
Returns: true if icon theme includes an icon for icon_name.

std::vector<String> Xfc::Gtk::IconTheme::list_icons | ( | const String & | context | ) |

  | Lists the icons in the current icon theme. Returns: A vector of String holding the names of all the icons in the theme. Only a subset of the icons can be listed by providing a context string. The set of values for the context string is system dependent, but will typically include such values as 'apps' and 'mimetypes'. Parameters:
  | context | A string identifying a particular type of icon, or null to list all icons.

Pointer<Gdk::Pixbuf> Xfc::Gtk::IconTheme::load_icon | ( | const String & | icon_name,
|  | int | size,
|  | IconLookupFlagsField | flags,
|  | G::Error * | error = `0`
| ) |

  | Looks up an icon in an icon theme, scales it to the given size and renders it into a pixbuf. Parameters:
  | icon_name | The name of the icon to lookup.
  | size | The desired icon size.
  | flags | The Gtk::IconLookupFlags modifying the behavior of the icon lookup.
  | error | The location to store error information on failure, or null.
Returns: A smart pointer to the rendered icon, or null if the icon isn't found. This is a convenience method; if more details about the icon are needed, use lookup_icon() followed by Gtk::IconInfo::load_icon(). Note the size of the resulting icon may not be exactly the requested size (see load_icon()). The rendered icon may be a newly created icon or a new reference to an internal icon, so you must not modify the icon.

Pointer<IconInfo> Xfc::Gtk::IconTheme::lookup_icon | ( | const String & | icon_name,
|  | int | size,
|  | IconLookupFlagsField | flags
| ) |

  | Looks up a named icon and returns a structure containing information such as the filename of the icon. Parameters:
  | icon_name | The name of the icon to lookup.
  | size | The desired icon size.
  | flags | The Gtk::IconLookupFlags modifying the behavior of the icon lookup.
Returns: An IconInfo object containing information about the icon, or null if no icon was found. The icon can then be rendered into a pixbuf using Gtk::IconInfo::load_icon(). Gtk::IconTheme::load_icon() combines these two steps if all you need is the pixbuf.

void Xfc::Gtk::IconTheme::prepend_search_path | ( | const String & | path | ) |

  | Prepends a directory to the search path (see set_search_path()). Parameters:
  | path | The directory name to prepend to the icon path.

bool Xfc::Gtk::IconTheme::rescan_if_needed | ( |  | ) |

| Checks to see if the icon theme has changed; if it has, any currently cached information is discarded and will be reloaded next time the icon theme is accessed. Returns: true if the icon theme has changed and needed to be reloaded.

void Xfc::Gtk::IconTheme::set_custom_theme | ( | const String & | theme_name | ) |

  | Sets the name of the icon theme that the IconTheme object uses, overriding system configuration. Parameters:
  | theme_name | The name of icon theme to use instead of the configured theme.
This method cannot be called on the icon theme objects returned from get_for_screen().

void Xfc::Gtk::IconTheme::set_screen | ( | Gdk::Screen * | screen | ) |

  | Sets the screen for an icon theme. Parameters:
  | screen | A Gdk::Screen.
The screen is used to track the user's currently configured icon theme, which might be different for different screens.

void Xfc::Gtk::IconTheme::set_search_path | ( | const std::vector< String > & | path | ) |

  | Sets the search path for the icon theme object. Parameters:
  | path | A vector of directories that are searched for icon themes.
When looking for an icon theme, GTK+ will search for a subdirectory of one or more of the directories in path with the same name as the icon theme. Note, themes from multiple of the path elements are combined to allow themes to be extended by adding icons in the user's home directory. In addition if an icon found isn't found either in the current icon theme or the default icon theme, and an image file with the right name is found directly in one of the elements of path, then that image will be used for the icon name. (This is legacy feature, and new icons should be put into the default icon theme, which is called DEFAULT_THEME_NAME, rather than directly on the icon path.)

## Member Data Documentation

const ChangedSignalType Xfc::Gtk::IconTheme::changed_signal`[static, protected]`

| Changed signal (see signal_changed()). Calls a slot with the signature:
                 void function();

The documentation for this class was generated from the following file:

- icontheme.hh

Xfce Foundation Classes

Copyright © 2004-2005 The XFC Development Team | XFC 4.3