2 * @defgroup Theme Theme
4 * Elementary uses Edje to theme its widgets, naturally. But for the most
5 * part this is hidden behind a simpler interface that lets the user set
6 * extensions and choose the style of widgets in a much easier way.
8 * Instead of thinking in terms of paths to Edje files and their groups
9 * each time you want to change the appearance of a widget, Elementary
10 * works so you can add any theme file with extensions or replace the
11 * main theme at one point in the application, and then just set the style
12 * of widgets with elm_object_style_set() and related functions. Elementary
13 * will then look in its list of themes for a matching group and apply it,
14 * and when the theme changes midway through the application, all widgets
15 * will be updated accordingly.
17 * There are three concepts you need to know to understand how Elementary
18 * theming works: default theme, extensions and overlays.
20 * Default theme, obviously enough, is the one that provides the default
21 * look of all widgets. End users can change the theme used by Elementary
22 * by setting the @c ELM_THEME environment variable before running an
23 * application, or globally for all programs using the @c elementary_config
24 * utility. Applications can change the default theme using elm_theme_set(),
25 * but this can go against the user wishes, so it's not an adviced practice.
27 * Ideally, applications should find everything they need in the already
28 * provided theme, but there may be occasions when that's not enough and
29 * custom styles are required to correctly express the idea. For this
30 * cases, Elementary has extensions.
32 * Extensions allow the application developer to write styles of its own
33 * to apply to some widgets. This requires knowledge of how each widget
34 * is themed, as extensions will always replace the entire group used by
35 * the widget, so important signals and parts need to be there for the
36 * object to behave properly (see documentation of Edje for details).
37 * Once the theme for the extension is done, the application needs to add
38 * it to the list of themes Elementary will look into, using
39 * elm_theme_extension_add(), and set the style of the desired widgets as
40 * he would normally with elm_object_style_set().
42 * Overlays, on the other hand, can replace the look of all widgets by
43 * overriding the default style. Like extensions, it's up to the application
44 * developer to write the theme for the widgets it wants, the difference
45 * being that when looking for the theme, Elementary will check first the
46 * list of overlays, then the set theme and lastly the list of extensions,
47 * so with overlays it's possible to replace the default view and every
48 * widget will be affected. This is very much alike to setting the whole
49 * theme for the application and will probably clash with the end user
50 * options, not to mention the risk of ending up with not matching styles
51 * across the program. Unless there's a very special reason to use them,
52 * overlays should be avoided for the resons exposed before.
54 * All these theme lists are handled by ::Elm_Theme instances. Elementary
55 * keeps one default internally and every function that receives one of
56 * these can be called with NULL to refer to this default (except for
57 * elm_theme_free()). It's possible to create a new instance of a
58 * ::Elm_Theme to set other theme for a specific widget (and all of its
59 * children), but this is as discouraged, if not even more so, than using
60 * overlays. Don't use this unless you really know what you are doing.
62 * But to be less negative about things, you can look at the following
64 * @li @ref theme_example_01 "Using extensions"
65 * @li @ref theme_example_02 "Using overlays"
72 * Opaque handler for the list of themes Elementary looks for when
75 * Stay out of this unless you really know what you are doing. For most
76 * cases, sticking to the default is all a developer needs.
78 typedef struct _Elm_Theme Elm_Theme;
81 * Create a new specific theme
83 * This creates an empty specific theme that only uses the default theme. A
84 * specific theme has its own private set of extensions and overlays too
85 * (which are empty by default). Specific themes do not fall back to themes
86 * of parent objects. They are not intended for this use. Use styles, overlays
87 * and extensions when needed, but avoid specific themes unless there is no
88 * other way (example: you want to have a preview of a new theme you are
89 * selecting in a "theme selector" window. The preview is inside a scroller
90 * and should display what the theme you selected will look like, but not
91 * actually apply it yet. The child of the scroller will have a specific
92 * theme set to show this preview before the user decides to apply it to all
95 EAPI Elm_Theme *elm_theme_new(void);
98 * Free a specific theme
100 * @param th The theme to free
102 * This frees a theme created with elm_theme_new().
104 EAPI void elm_theme_free(Elm_Theme *th);
107 * Copy the theme fom the source to the destination theme
109 * @param th The source theme to copy from
110 * @param thdst The destination theme to copy data to
112 * This makes a one-time static copy of all the theme config, extensions
113 * and overlays from @p th to @p thdst. If @p th references a theme, then
114 * @p thdst is also set to reference it, with all the theme settings,
115 * overlays and extensions that @p th had.
117 EAPI void elm_theme_copy(Elm_Theme *th, Elm_Theme *thdst);
120 * Tell the source theme to reference the ref theme
122 * @param th The theme that will do the referencing
123 * @param thref The theme that is the reference source
125 * This clears @p th to be empty and then sets it to refer to @p thref
126 * so @p th acts as an override to @p thref, but where its overrides
127 * don't apply, it will fall through to @p thref for configuration.
129 EAPI void elm_theme_ref_set(Elm_Theme *th, Elm_Theme *thref);
132 * Return the theme referred to
134 * @param th The theme to get the reference from
135 * @return The referenced theme handle
137 * This gets the theme set as the reference theme by elm_theme_ref_set().
138 * If no theme is set as a reference, NULL is returned.
140 EAPI Elm_Theme *elm_theme_ref_get(Elm_Theme *th);
143 * Return the default theme
145 * @return The default theme handle
147 * This returns the internal default theme setup handle that all widgets
148 * use implicitly unless a specific theme is set. This is also often use
149 * as a shorthand of NULL.
151 EAPI Elm_Theme *elm_theme_default_get(void);
154 * Prepends a theme overlay to the list of overlays
156 * @param th The theme to add to, or if NULL, the default theme
157 * @param item The Edje file path to be used
159 * Use this if your application needs to provide some custom overlay theme
160 * (An Edje file that replaces some default styles of widgets) where adding
161 * new styles, or changing system theme configuration is not possible. Do
162 * NOT use this instead of a proper system theme configuration. Use proper
163 * configuration files, profiles, environment variables etc. to set a theme
164 * so that the theme can be altered by simple confiugration by a user. Using
165 * this call to achieve that effect is abusing the API and will create lots
168 * @see elm_theme_extension_add()
170 EAPI void elm_theme_overlay_add(Elm_Theme *th, const char *item);
173 * Delete a theme overlay from the list of overlays
175 * @param th The theme to delete from, or if NULL, the default theme
176 * @param item The name of the theme overlay
178 * @see elm_theme_overlay_add()
180 EAPI void elm_theme_overlay_del(Elm_Theme *th, const char *item);
183 * Appends a theme extension to the list of extensions.
185 * @param th The theme to add to, or if NULL, the default theme
186 * @param item The Edje file path to be used
188 * This is intended when an application needs more styles of widgets or new
189 * widget themes that the default does not provide (or may not provide). The
190 * application has "extended" usage by coming up with new custom style names
191 * for widgets for specific uses, but as these are not "standard", they are
192 * not guaranteed to be provided by a default theme. This means the
193 * application is required to provide these extra elements itself in specific
194 * Edje files. This call adds one of those Edje files to the theme search
195 * path to be search after the default theme. The use of this call is
196 * encouraged when default styles do not meet the needs of the application.
197 * Use this call instead of elm_theme_overlay_add() for almost all cases.
199 * @see elm_object_style_set()
201 EAPI void elm_theme_extension_add(Elm_Theme *th, const char *item);
204 * Deletes a theme extension from the list of extensions.
206 * @param th The theme to delete from, or if NULL, the default theme
207 * @param item The name of the theme extension
209 * @see elm_theme_extension_add()
211 EAPI void elm_theme_extension_del(Elm_Theme *th, const char *item);
214 * Set the theme search order for the given theme
216 * @param th The theme to set the search order, or if NULL, the default theme
217 * @param theme Theme search string
219 * This sets the search string for the theme in path-notation from first
220 * theme to search, to last, delimited by the : character. Example:
222 * "shiny:/path/to/file.edj:default"
224 * See the ELM_THEME environment variable for more information.
226 * @see elm_theme_get()
227 * @see elm_theme_list_get()
229 EAPI void elm_theme_set(Elm_Theme *th, const char *theme);
232 * Return the theme search order
234 * @param th The theme to get the search order, or if NULL, the default theme
235 * @return The internal search order path
237 * This function returns a colon separated string of theme elements as
238 * returned by elm_theme_list_get().
240 * @see elm_theme_set()
241 * @see elm_theme_list_get()
243 EAPI const char *elm_theme_get(Elm_Theme *th);
246 * Return a list of theme elements to be used in a theme.
248 * @param th Theme to get the list of theme elements from.
249 * @return The internal list of theme elements
251 * This returns the internal list of theme elements (will only be valid as
252 * long as the theme is not modified by elm_theme_set() or theme is not
253 * freed by elm_theme_free(). This is a list of strings which must not be
254 * altered as they are also internal. If @p th is NULL, then the default
255 * theme element list is returned.
257 * A theme element can consist of a full or relative path to a .edj file,
258 * or a name, without extension, for a theme to be searched in the known
259 * theme paths for Elemementary.
261 * @see elm_theme_set()
262 * @see elm_theme_get()
264 EAPI const Eina_List *elm_theme_list_get(const Elm_Theme *th);
267 * Return the full patrh for a theme element
269 * @param f The theme element name
270 * @param in_search_path Pointer to a boolean to indicate if item is in the search path or not
271 * @return The full path to the file found.
273 * This returns a string you should free with free() on success, NULL on
274 * failure. This will search for the given theme element, and if it is a
275 * full or relative path element or a simple searchable name. The returned
276 * path is the full path to the file, if searched, and the file exists, or it
277 * is simply the full path given in the element or a resolved path if
278 * relative to home. The @p in_search_path boolean pointed to is set to
279 * EINA_TRUE if the file was a searchable file andis in the search path,
280 * and EINA_FALSE otherwise.
282 EAPI char *elm_theme_list_item_path_get(const char *f, Eina_Bool *in_search_path);
285 * Flush the current theme.
287 * @param th Theme to flush
289 * This flushes caches that let elementary know where to find theme elements
290 * in the given theme. If @p th is NULL, then the default theme is flushed.
291 * Call this function if source theme data has changed in such a way as to
292 * make any caches Elementary kept invalid.
294 EAPI void elm_theme_flush(Elm_Theme *th);
297 * This flushes all themes (default and specific ones).
299 * This will flush all themes in the current application context, by calling
300 * elm_theme_flush() on each of them.
302 EAPI void elm_theme_full_flush(void);
305 * Set the theme for all elementary using applications on the current display
307 * @param theme The name of the theme to use. Format same as the ELM_THEME
308 * environment variable.
310 EAPI void elm_theme_all_set(const char *theme);
313 * Return a list of theme elements in the theme search path
315 * @return A list of strings that are the theme element names.
317 * This lists all available theme files in the standard Elementary search path
318 * for theme elements, and returns them in alphabetical order as theme
319 * element names in a list of strings. Free this with
320 * elm_theme_name_available_list_free() when you are done with the list.
322 EAPI Eina_List *elm_theme_name_available_list_new(void);
325 * Free the list returned by elm_theme_name_available_list_new()
327 * This frees the list of themes returned by
328 * elm_theme_name_available_list_new(). Once freed the list should no longer
329 * be used. a new list mys be created.
331 EAPI void elm_theme_name_available_list_free(Eina_List *list);
334 * Set a specific theme to be used for this object and its children
336 * @param obj The object to set the theme on
337 * @param th The theme to set
339 * This sets a specific theme that will be used for the given object and any
340 * child objects it has. If @p th is NULL then the theme to be used is
341 * cleared and the object will inherit its theme from its parent (which
342 * ultimately will use the default theme if no specific themes are set).
344 * Use special themes with great care as this will annoy users and make
345 * configuration difficult. Avoid any custom themes at all if it can be
349 elm_object_theme_set(Evas_Object *obj, Elm_Theme *th)
353 * Get the specific theme to be used
355 * @param obj The object to get the specific theme from
356 * @return The specifc theme set.
358 * This will return a specific theme set, or NULL if no specific theme is
359 * set on that object. It will not return inherited themes from parents, only
360 * the specific theme set for that specific object. See elm_object_theme_set()
361 * for more information.
363 EAPI Elm_Theme *elm_object_theme_get(const Evas_Object *obj) EINA_ARG_NONNULL(1);
366 * Get a data item from a theme
368 * @param th The theme, or NULL for default theme
369 * @param key The data key to search with
370 * @return The data value, or NULL on failure
372 * This function is used to return data items from edc in @p th, an overlay, or an extension.
373 * It works the same way as edje_file_data_get() except that the return is stringshared.
375 EAPI const char *elm_theme_data_get(Elm_Theme *th, const char *key) EINA_ARG_NONNULL(2);