path: root/libraries/elementary/src/lib/elm_layout.h

/**
 * @defgroup Layout Layout
 * @ingroup Elementary
 *
 * @image html img/widget/layout/preview-00.png
 * @image latex img/widget/layout/preview-00.eps width=\textwidth
 *
 * @image html img/layout-predefined.png
 * @image latex img/layout-predefined.eps width=\textwidth
 *
 * This is a container widget that takes a standard Edje design file and
 * wraps it very thinly in a widget.
 *
 * An Edje design (theme) file has a very wide range of possibilities to
 * describe the behavior of elements added to the Layout. Check out the Edje
 * documentation and the EDC reference to get more information about what can
 * be done with Edje.
 *
 * Just like @ref List, @ref Box, and other container widgets, any
 * object added to the Layout will become its child, meaning that it will be
 * deleted if the Layout is deleted, move if the Layout is moved, and so on.
 *
 * The Layout widget can contain as many Contents, Boxes or Tables as
 * described in its theme file. For instance, objects can be added to
 * different Tables by specifying the respective Table part names. The same
 * is valid for Content and Box.
 *
 * The objects added as child of the Layout will behave as described in the
 * part description where they were added. There are 3 possible types of
 * parts where a child can be added:
 *
 * @section secContent Content (SWALLOW part)
 *
 * Only one object can be added to the @c SWALLOW part (but you still can
 * have many @c SWALLOW parts and one object on each of them). Use the @c
 * elm_object_content_set/get/unset functions to set, retrieve and unset
 * objects as content of the @c SWALLOW. After being set to this part, the
 * object size, position, visibility, clipping and other description
 * properties will be totally controlled by the description of the given part
 * (inside the Edje theme file).
 *
 * One can use @c evas_object_size_hint_* functions on the child to have some
 * kind of control over its behavior, but the resulting behavior will still
 * depend heavily on the @c SWALLOW part description.
 *
 * The Edje theme also can change the part description, based on signals or
 * scripts running inside the theme. This change can also be animated. All of
 * this will affect the child object set as content accordingly. The object
 * size will be changed if the part size is changed, it will animate move if
 * the part is moving, and so on.
 *
 * The following picture demonstrates a Layout widget with a child object
 * added to its @c SWALLOW:
 *
 * @image html layout_swallow.png
 * @image latex layout_swallow.eps width=\textwidth
 *
 * @section secBox Box (BOX part)
 *
 * An Edje @c BOX part is very similar to the Elementary @ref Box widget. It
 * allows one to add objects to the box and have them distributed along its
 * area, accordingly to the specified @a layout property (now by @a layout we
 * mean the chosen layouting design of the Box, not the Layout widget
 * itself).
 *
 * A similar effect for having a box with its position, size and other things
 * controlled by the Layout theme would be to create an Elementary @ref Box
 * widget and add it as a Content in the @c SWALLOW part.
 *
 * The main difference of using the Layout Box is that its behavior, the box
 * properties like layouting format, padding, align, etc. will be all
 * controlled by the theme. This means, for example, that a signal could be
 * sent to the Layout theme (with elm_object_signal_emit()) and the theme
 * handled the signal by changing the box padding, or align, or both. Using
 * the Elementary @ref Box widget is not necessarily harder or easier, it
 * just depends on the circumstances and requirements.
 *
 * The Layout Box can be used through the @c elm_layout_box_* set of
 * functions.
 *
 * The following picture demonstrates a Layout widget with many child objects
 * added to its @c BOX part:
 *
 * @image html layout_box.png
 * @image latex layout_box.eps width=\textwidth
 *
 * @section secTable Table (TABLE part)
 *
 * Just like the @ref secBox, the Layout Table is very similar to the
 * Elementary @ref Table widget. It allows one to add objects to the Table
 * specifying the row and column where the object should be added, and any
 * column or row span if necessary.
 *
 * Again, we could have this design by adding a @ref Table widget to the @c
 * SWALLOW part using elm_object_part_content_set(). The same difference happens
 * here when choosing to use the Layout Table (a @c TABLE part) instead of
 * the @ref Table plus @c SWALLOW part. It's just a matter of convenience.
 *
 * The Layout Table can be used through the @c elm_layout_table_* set of
 * functions.
 *
 * The following picture demonstrates a Layout widget with many child objects
 * added to its @c TABLE part:
 *
 * @image html layout_table.png
 * @image latex layout_table.eps width=\textwidth
 *
 * @section secPredef Predefined Layouts
 *
 * Another interesting thing about the Layout widget is that it offers some
 * predefined themes that come with the default Elementary theme. These
 * themes can be set by the call elm_layout_theme_set(), and provide some
 * basic functionality depending on the theme used.
 *
 * Most of them already send some signals, some already provide a toolbar or
 * back and next buttons.
 *
 * These are available predefined theme layouts. All of them have class = @c
 * layout, group = @c application, and style = one of the following options:
 *
 * @li @c toolbar-content - application with toolbar and main content area
 * @li @c toolbar-content-back - application with toolbar and main content
 * area with a back button and title area
 * @li @c toolbar-content-back-next - application with toolbar and main
 * content area with a back and next buttons and title area
 * @li @c content-back - application with a main content area with a back
 * button and title area
 * @li @c content-back-next - application with a main content area with a
 * back and next buttons and title area
 * @li @c toolbar-vbox - application with toolbar and main content area as a
 * vertical box
 * @li @c toolbar-table - application with toolbar and main content area as a
 * table
 *
 * Supported elm_object common APIs.
 * @li @ref elm_object_signal_emit
 * @li @ref elm_object_signal_callback_add
 * @li @ref elm_object_signal_callback_del
 * @li @ref elm_object_part_text_set
 * @li @ref elm_object_part_text_get
 * @li @ref elm_object_part_content_set
 * @li @ref elm_object_part_content_get
 * @li @ref elm_object_part_content_unset
 *
 * @section secExamples Examples
 *
 * Some examples of the Layout widget can be found here:
 * @li @ref layout_example_01
 * @li @ref layout_example_02
 * @li @ref layout_example_03
 * @li @ref layout_example_edc
 *
 */

/**
 * Add a new layout to the parent
 *
 * @param parent The parent object
 * @return The new object or NULL if it cannot be created
 *
 * @see elm_layout_file_set()
 * @see elm_layout_theme_set()
 *
 * @ingroup Layout
 */
EAPI Evas_Object                 *elm_layout_add(Evas_Object *parent);

/**
 * Set the file that will be used as layout
 *
 * @param obj The layout object
 * @param file The path to file (edj) that will be used as layout
 * @param group The group that the layout belongs in edje file
 *
 * @return (1 = success, 0 = error)
 *
 * @ingroup Layout
 */
EAPI Eina_Bool                    elm_layout_file_set(Evas_Object *obj, const char *file, const char *group);

/**
 * Set the edje group from the elementary theme that will be used as layout
 *
 * @param obj The layout object
 * @param clas the class of the group
 * @param group the group
 * @param style the style to used
 *
 * @return (1 = success, 0 = error)
 *
 * @ingroup Layout
 */
EAPI Eina_Bool                    elm_layout_theme_set(Evas_Object *obj, const char *clas, const char *group, const char *style);

/**
 * Append child to layout box part.
 *
 * @param obj the layout object
 * @param part the box part to which the object will be appended.
 * @param child the child object to append to box.
 * @return @c EINA_TRUE on success, @c EINA_FALSE otherwise
 *
 * Once the object is appended, it will become child of the layout. Its
 * lifetime will be bound to the layout, whenever the layout dies the child
 * will be deleted automatically. One should use elm_layout_box_remove() to
 * make this layout forget about the object.
 *
 * @see elm_layout_box_prepend()
 * @see elm_layout_box_insert_before()
 * @see elm_layout_box_insert_at()
 * @see elm_layout_box_remove()
 *
 * @ingroup Layout
 */
EAPI Eina_Bool                    elm_layout_box_append(Evas_Object *obj, const char *part, Evas_Object *child);

/**
 * Prepend child to layout box part.
 *
 * @param obj the layout object
 * @param part the box part to prepend.
 * @param child the child object to prepend to box.
 * @return @c EINA_TRUE on success, @c EINA_FALSE otherwise
 *
 * Once the object is prepended, it will become child of the layout. Its
 * lifetime will be bound to the layout, whenever the layout dies the child
 * will be deleted automatically. One should use elm_layout_box_remove() to
 * make this layout forget about the object.
 *
 * @see elm_layout_box_append()
 * @see elm_layout_box_insert_before()
 * @see elm_layout_box_insert_at()
 * @see elm_layout_box_remove()
 *
 * @ingroup Layout
 */
EAPI Eina_Bool                    elm_layout_box_prepend(Evas_Object *obj, const char *part, Evas_Object *child);

/**
 * Insert child to layout box part before a reference object.
 *
 * @param obj the layout object
 * @param part the box part to insert.
 * @param child the child object to insert into box.
 * @param reference another reference object to insert before in box.
 * @return @c EINA_TRUE on success, @c EINA_FALSE otherwise
 *
 * Once the object is inserted, it will become child of the layout. Its
 * lifetime will be bound to the layout, whenever the layout dies the child
 * will be deleted automatically. One should use elm_layout_box_remove() to
 * make this layout forget about the object.
 *
 * @see elm_layout_box_append()
 * @see elm_layout_box_prepend()
 * @see elm_layout_box_insert_before()
 * @see elm_layout_box_remove()
 *
 * @ingroup Layout
 */
EAPI Eina_Bool                    elm_layout_box_insert_before(Evas_Object *obj, const char *part, Evas_Object *child, const Evas_Object *reference);

/**
 * Insert child to layout box part at a given position.
 *
 * @param obj the layout object
 * @param part the box part to insert.
 * @param child the child object to insert into box.
 * @param pos the numeric position >=0 to insert the child.
 * @return @c EINA_TRUE on success, @c EINA_FALSE otherwise
 *
 * Once the object is inserted, it will become child of the layout. Its
 * lifetime will be bound to the layout, whenever the layout dies the child
 * will be deleted automatically. One should use elm_layout_box_remove() to
 * make this layout forget about the object.
 *
 * @see elm_layout_box_append()
 * @see elm_layout_box_prepend()
 * @see elm_layout_box_insert_before()
 * @see elm_layout_box_remove()
 *
 * @ingroup Layout
 */
EAPI Eina_Bool                    elm_layout_box_insert_at(Evas_Object *obj, const char *part, Evas_Object *child, unsigned int pos);

/**
 * Remove a child of the given part box.
 *
 * @param obj The layout object
 * @param part The box part name to remove child.
 * @param child The object to remove from box.
 * @return The object that was being used, or NULL if not found.
 *
 * The object will be removed from the box part and its lifetime will
 * not be handled by the layout anymore. This is equivalent to
 * elm_object_part_content_unset() for box.
 *
 * @see elm_layout_box_append()
 * @see elm_layout_box_remove_all()
 *
 * @ingroup Layout
 */
EAPI Evas_Object                 *elm_layout_box_remove(Evas_Object *obj, const char *part, Evas_Object *child);

/**
 * Remove all children of the given part box.
 *
 * @param obj The layout object
 * @param part The box part name to remove child.
 * @param clear If EINA_TRUE, then all objects will be deleted as
 *        well, otherwise they will just be removed and will be
 *        dangling on the canvas.
 * @return @c EINA_TRUE on success, @c EINA_FALSE otherwise
 *
 * The objects will be removed from the box part and their lifetime will
 * not be handled by the layout anymore. This is equivalent to
 * elm_layout_box_remove() for all box children.
 *
 * @see elm_layout_box_append()
 * @see elm_layout_box_remove()
 *
 * @ingroup Layout
 */
EAPI Eina_Bool                    elm_layout_box_remove_all(Evas_Object *obj, const char *part, Eina_Bool clear);

/**
 * Insert child to layout table part.
 *
 * @param obj the layout object
 * @param part the box part to pack child.
 * @param child_obj the child object to pack into table.
 * @param col the column to which the child should be added. (>= 0)
 * @param row the row to which the child should be added. (>= 0)
 * @param colspan how many columns should be used to store this object. (>=
 *        1)
 * @param rowspan how many rows should be used to store this object. (>= 1)
 * @return @c EINA_TRUE on success, @c EINA_FALSE otherwise
 *
 * Once the object is inserted, it will become child of the table. Its
 * lifetime will be bound to the layout, and whenever the layout dies the
 * child will be deleted automatically. One should use
 * elm_layout_table_remove() to make this layout forget about the object.
 *
 * If @p colspan or @p rowspan are bigger than 1, that object will occupy
 * more space than a single cell. For instance, the following code:
 * @code
 * elm_layout_table_pack(layout, "table_part", child, 0, 1, 3, 1);
 * @endcode
 *
 * Would result in an object being added like the following picture:
 *
 * @image html layout_colspan.png
 * @image latex layout_colspan.eps width=\textwidth
 *
 * @see elm_layout_table_unpack()
 * @see elm_layout_table_clear()
 *
 * @ingroup Layout
 */
EAPI Eina_Bool                    elm_layout_table_pack(Evas_Object *obj, const char *part, Evas_Object *child_obj, unsigned short col, unsigned short row, unsigned short colspan, unsigned short rowspan);

/**
 * Unpack (remove) a child of the given part table.
 *
 * @param obj The layout object
 * @param part The table part name to remove child.
 * @param child_obj The object to remove from table.
 * @return The object that was being used, or NULL if not found.
 *
 * The object will be unpacked from the table part and its lifetime
 * will not be handled by the layout anymore. This is equivalent to
 * elm_object_part_content_unset() for table.
 *
 * @see elm_layout_table_pack()
 * @see elm_layout_table_clear()
 *
 * @ingroup Layout
 */
EAPI Evas_Object                 *elm_layout_table_unpack(Evas_Object *obj, const char *part, Evas_Object *child_obj);

/**
 * Remove all the child objects of the given part table.
 *
 * @param obj The layout object
 * @param part The table part name to remove child.
 * @param clear If EINA_TRUE, then all objects will be deleted as
 *        well, otherwise they will just be removed and will be
 *        dangling on the canvas.
 * @return @c EINA_TRUE on success, @c EINA_FALSE otherwise
 *
 * The objects will be removed from the table part and their lifetime will
 * not be handled by the layout anymore. This is equivalent to
 * elm_layout_table_unpack() for all table children.
 *
 * @see elm_layout_table_pack()
 * @see elm_layout_table_unpack()
 *
 * @ingroup Layout
 */
EAPI Eina_Bool                    elm_layout_table_clear(Evas_Object *obj, const char *part, Eina_Bool clear);

/**
 * Get the edje layout
 *
 * @param obj The layout object
 *
 * @return A Evas_Object with the edje layout settings loaded
 * with function elm_layout_file_set
 *
 * This returns the edje object. It is not expected to be used to then
 * swallow objects via edje_object_part_swallow() for example. Use
 * elm_object_part_content_set() instead so child object handling and sizing is
 * done properly.
 *
 * @note This function should only be used if you really need to call some
 * low level Edje function on this edje object. All the common stuff (setting
 * text, emitting signals, hooking callbacks to signals, etc.) can be done
 * with proper elementary functions.
 *
 * @see elm_object_signal_callback_add()
 * @see elm_object_signal_emit()
 * @see elm_object_part_text_set()
 * @see elm_object_part_content_set()
 * @see elm_layout_box_append()
 * @see elm_layout_table_pack()
 * @see elm_layout_data_get()
 *
 * @ingroup Layout
 */
EAPI Evas_Object                 *elm_layout_edje_get(const Evas_Object *obj);

/**
 * Get the edje data from the given layout
 *
 * @param obj The layout object
 * @param key The data key
 *
 * @return The edje data string
 *
 * This function fetches data specified inside the edje theme of this layout.
 * This function return NULL if data is not found.
 *
 * In EDC this comes from a data block within the group block that @p
 * obj was loaded from. E.g.
 *
 * @code
 * collections {
 *   group {
 *     name: "a_group";
 *     data {
 *       item: "key1" "value1";
 *       item: "key2" "value2";
 *     }
 *   }
 * }
 * @endcode
 *
 * @ingroup Layout
 */
EAPI const char                  *elm_layout_data_get(const Evas_Object *obj, const char *key);

/**
 * Eval sizing
 *
 * @param obj The layout object
 *
 * Manually forces a sizing re-evaluation. This is useful when the minimum
 * size required by the edje theme of this layout has changed. The change on
 * the minimum size required by the edje theme is not immediately reported to
 * the elementary layout, so one needs to call this function in order to tell
 * the widget (layout) that it needs to reevaluate its own size.
 *
 * The minimum size of the theme is calculated based on minimum size of
 * parts, the size of elements inside containers like box and table, etc. All
 * of this can change due to state changes, and that's when this function
 * should be called.
 *
 * Also note that a standard signal of "size,eval" "elm" emitted from the
 * edje object will cause this to happen too.
 *
 * @ingroup Layout
 */
EAPI void                         elm_layout_sizing_eval(Evas_Object *obj);

/**
 * Sets a specific cursor for an edje part.
 *
 * @param obj The layout object.
 * @param part_name a part from loaded edje group.
 * @param cursor cursor name to use, see Elementary_Cursor.h
 *
 * @return EINA_TRUE on success or EINA_FALSE on failure, that may be
 *         part not exists or it has "mouse_events: 0".
 *
 * @ingroup Layout
 */
EAPI Eina_Bool                    elm_layout_part_cursor_set(Evas_Object *obj, const char *part_name, const char *cursor);

/**
 * Get the cursor to be shown when mouse is over an edje part
 *
 * @param obj The layout object.
 * @param part_name a part from loaded edje group.
 * @return the cursor name.
 *
 * @ingroup Layout
 */
EAPI const char                  *elm_layout_part_cursor_get(const Evas_Object *obj, const char *part_name);

/**
 * Unsets a cursor previously set with elm_layout_part_cursor_set().
 *
 * @param obj The layout object.
 * @param part_name a part from loaded edje group, that had a cursor set
 *        with elm_layout_part_cursor_set().
 * @return @c EINA_TRUE on success, @c EINA_FALSE otherwise
 *
 * @ingroup Layout
 */
EAPI Eina_Bool                    elm_layout_part_cursor_unset(Evas_Object *obj, const char *part_name);

/**
 * Sets a specific cursor style for an edje part.
 *
 * @param obj The layout object.
 * @param part_name a part from loaded edje group.
 * @param style the theme style to use (default, transparent, ...)
 *
 * @return EINA_TRUE on success or EINA_FALSE on failure, that may be
 *         part not exists or it did not had a cursor set.
 *
 * @ingroup Layout
 */
EAPI Eina_Bool                    elm_layout_part_cursor_style_set(Evas_Object *obj, const char *part_name, const char *style);

/**
 * Gets a specific cursor style for an edje part.
 *
 * @param obj The layout object.
 * @param part_name a part from loaded edje group.
 *
 * @return the theme style in use, defaults to "default". If the
 *         object does not have a cursor set, then NULL is returned.
 *
 * @ingroup Layout
 */
EAPI const char                  *elm_layout_part_cursor_style_get(const Evas_Object *obj, const char *part_name);

/**
 * Sets if the cursor set should be searched on the theme or should use
 * the provided by the engine, only.
 *
 * @note before you set if should look on theme you should define a
 * cursor with elm_layout_part_cursor_set(). By default it will only
 * look for cursors provided by the engine.
 *
 * @param obj The layout object.
 * @param part_name a part from loaded edje group.
 * @param engine_only if cursors should be just provided by the engine (EINA_TRUE)
 *        or should also search on widget's theme as well (EINA_FALSE)
 *
 * @return EINA_TRUE on success or EINA_FALSE on failure, that may be
 *         part not exists or it did not had a cursor set.
 *
 * @ingroup Layout
 */
EAPI Eina_Bool                    elm_layout_part_cursor_engine_only_set(Evas_Object *obj, const char *part_name, Eina_Bool engine_only);

/**
 * Gets a specific cursor engine_only for an edje part.
 *
 * @param obj The layout object.
 * @param part_name a part from loaded edje group.
 *
 * @return whenever the cursor is just provided by engine or also from theme.
 *
 * @ingroup Layout
 */
EAPI Eina_Bool                    elm_layout_part_cursor_engine_only_get(const Evas_Object *obj, const char *part_name);

/**
 * @def elm_layout_icon_set
 * Convenience macro to set the icon object in a layout that follows the
 * Elementary naming convention for its parts.
 *
 * @ingroup Layout
 */
#define elm_layout_icon_set(_ly, _obj)                                 \
  do {                                                                 \
       const char *sig;                                                \
       elm_object_part_content_set((_ly), "elm.swallow.icon", (_obj)); \
       if ((_obj)) sig = "elm,state,icon,visible";                     \
       else sig = "elm,state,icon,hidden";                             \
       elm_object_signal_emit((_ly), sig, "elm");                      \
    } while (0)

/**
 * @def elm_layout_icon_get
 * Convenience macro to get the icon object from a layout that follows the
 * Elementary naming convention for its parts.
 *
 * @ingroup Layout
 */
#define elm_layout_icon_get(_ly) \
  elm_object_part_content_get((_ly), "elm.swallow.icon")

/**
 * @def elm_layout_end_set
 * Convenience macro to set the end object in a layout that follows the
 * Elementary naming convention for its parts.
 *
 * @ingroup Layout
 */
#define elm_layout_end_set(_ly, _obj)                                 \
  do {                                                                \
       const char *sig;                                               \
       elm_object_part_content_set((_ly), "elm.swallow.end", (_obj)); \
       if ((_obj)) sig = "elm,state,end,visible";                     \
       else sig = "elm,state,end,hidden";                             \
       elm_object_signal_emit((_ly), sig, "elm");                     \
    } while (0)

/**
 * @def elm_layout_end_get
 * Convenience macro to get the end object in a layout that follows the
 * Elementary naming convention for its parts.
 *
 * @ingroup Layout
 */
#define elm_layout_end_get(_ly) \
  elm_object_part_content_get((_ly), "elm.swallow.end")

/* smart callbacks called:
 * "theme,changed" - when elm theme is changed.
 */

/**
 * @}
 */