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| author | jacqueline <me@jacqueline.id.au> | 2024-06-12 17:54:40 +1000 |
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| committer | jacqueline <me@jacqueline.id.au> | 2024-06-12 17:54:40 +1000 |
| commit | 64bd9053a25297f7a442ca831c7da5b44bd33f84 (patch) | |
| tree | a90c6cad25a12028302ab1a5334510fba0229bae /lib/lvgl/docs/widgets/obj.md | |
| parent | 611176ed667c4ed7ee9f609e958f9404f4aee91d (diff) | |
| download | tangara-fw-64bd9053a25297f7a442ca831c7da5b44bd33f84.tar.gz | |
Update LVGL to v9.1.0
Diffstat (limited to 'lib/lvgl/docs/widgets/obj.md')
| -rw-r--r-- | lib/lvgl/docs/widgets/obj.md | 198 |
1 files changed, 0 insertions, 198 deletions
diff --git a/lib/lvgl/docs/widgets/obj.md b/lib/lvgl/docs/widgets/obj.md deleted file mode 100644 index c6354682..00000000 --- a/lib/lvgl/docs/widgets/obj.md +++ /dev/null @@ -1,198 +0,0 @@ -# Base object (lv_obj) - -## Overview - -The 'Base Object' implements the basic properties of widgets on a screen, such as: -- coordinates -- parent object -- children -- contains the styles -- attributes like *Clickable*, *Scrollable*, etc. - -In object-oriented thinking, it is the base class from which all other objects in LVGL are inherited. - -The functions and functionalities of the Base object can be used with other widgets too. For example `lv_obj_set_width(slider, 100)` - -The Base object can be directly used as a simple widget: it's nothing more than a rectangle. In HTML terms, think of it as a `<div>`. - -### Coordinates - -Only a small subset of coordinate settings is described here. To see all the features of LVGL (padding, coordinates in styles, layouts, etc) visit the [Coordinates](/overview/coords) page. - -#### Size -The object size can be modified on individual axes with `lv_obj_set_width(obj, new_width)` and `lv_obj_set_height(obj, new_height)`, or both axes can be modified at the same time with `lv_obj_set_size(obj, new_width, new_height)`. - -#### Position -You can set the position relative to the parent with `lv_obj_set_x(obj, new_x)` and `lv_obj_set_y(obj, new_y)`, or both axes at the same time with `lv_obj_set_pos(obj, new_x, new_y)`. - -#### Alignment -You can align the object on its parent with `lv_obj_set_align(obj, LV_ALIGN_...)`. After this every x and y setting will be relative to the set alignment mode. -For example, this will shift the object by 10;20 px from the center of its parent: -```c -lv_obj_set_align(obj, LV_ALIGN_CENTER); -lv_obj_set_pos(obj, 10, 20); - -//Or in one function -lv_obj_align(obj, LV_ALIGN_CENTER, 10, 20); -``` - -To align one object to another use: `lv_obj_align_to(obj_to_align, obj_referece, LV_ALIGN_..., x, y)` - -For example, to align a text below an image: `lv_obj_align_to(text, image, LV_ALIGN_OUT_BOTTOM_MID, 0, 10)`. - -The following align types exist: - - - -### Parents and children -You can set a new parent for an object with `lv_obj_set_parent(obj, new_parent)`. To get the current parent, use `lv_obj_get_parent(obj)`. - -To get a specific child of a parent use `lv_obj_get_child(parent, idx)`. Some examples for `idx`: -- `0` get the child created first -- `1` get the child created second -- `-1` get the child created last - -The children can be iterated lke this: -```c -uint32_t i; -for(i = 0; i < lv_obj_get_child_cnt(parent); i++) { - lv_obj_t * child = lv_obj_get_child(parent, i); - /*Do something with child*/ -} -``` - -`lv_obj_get_index(obj)` returns the index of the object in its parent. It is equivalent to the number of younger children in the parent. - -You can bring an object to the foreground or send it to the background with `lv_obj_move_foreground(obj)` and `lv_obj_move_background(obj)`. - -You can change the index of an object in its parent using `lv_obj_move_to_index(obj, index)`. - -You can swap the position of two objects with `lv_obj_swap(obj1, obj2)`. - -### Display and Screens - -At the highest level of the LVGL object hierarchy is the *display* which represents the driver for a display device (physical display or simulator). A display can have one or more screens associated with it. Each screen contains a hierarchy of objects for graphical widgets representing a layout that covers the entire display. - -When you have created a screen like `lv_obj_t * screen = lv_obj_create(NULL)`, you can make it active with `lv_scr_load(screen)`. The `lv_scr_act()` function gives you a pointer to the active screen. - -If you have multiple displays, it's important to know that the screen functions operate on the most recently created display or the one explicitly selected with `lv_disp_set_default`. - -To get an object's screen use the `lv_obj_get_screen(obj)` function. - -### Events - -To set an event callback for an object, use `lv_obj_add_event_cb(obj, event_cb, LV_EVENT_..., user_data)`, - -To manually send an event to an object, use `lv_event_send(obj, LV_EVENT_..., param)` - -Read the [Event overview](/overview/event) to learn more about events. - - -### Styles -Be sure to read the [Style overview](/overview/style). Here only the most essential functions are described. - -A new style can be added to an object with the `lv_obj_add_style(obj, &new_style, selector)` function. -`selector` is an ORed combination of part and state(s). E.g. `LV_PART_SCROLLBAR | LV_STATE_PRESSED`. - -The base objects use `LV_PART_MAIN` style properties and `LV_PART_SCROLLBAR` with the typical background style properties. - - -### Flags -There are some attributes which can be enabled/disabled by `lv_obj_add/clear_flag(obj, LV_OBJ_FLAG_...)`: - -- `LV_OBJ_FLAG_HIDDEN` Make the object hidden. (Like it wasn't there at all) -- `LV_OBJ_FLAG_CLICKABLE` Make the object clickable by input devices -- `LV_OBJ_FLAG_CLICK_FOCUSABLE` Add focused state to the object when clicked -- `LV_OBJ_FLAG_CHECKABLE` Toggle checked state when the object is clicked -- `LV_OBJ_FLAG_SCROLLABLE` Make the object scrollable -- `LV_OBJ_FLAG_SCROLL_ELASTIC` Allow scrolling inside but with slower speed -- `LV_OBJ_FLAG_SCROLL_MOMENTUM` Make the object scroll further when "thrown" -- `LV_OBJ_FLAG_SCROLL_ONE` Allow scrolling only one snappable children -- `LV_OBJ_FLAG_SCROLL_CHAIN_HOR` Allow propagating the horizontal scroll to a parent -- `LV_OBJ_FLAG_SCROLL_CHAIN_VER` Allow propagating the vertical scroll to a parent -- `LV_OBJ_FLAG_SCROLL_CHAIN` Simple packaging for (`LV_OBJ_FLAG_SCROLL_CHAIN_HOR | LV_OBJ_FLAG_SCROLL_CHAIN_VER`) -- `LV_OBJ_FLAG_SCROLL_ON_FOCUS` Automatically scroll object to make it visible when focused -- `LV_OBJ_FLAG_SCROLL_WITH_ARROW` Allow scrolling the focused object with arrow keys -- `LV_OBJ_FLAG_SNAPPABLE` If scroll snap is enabled on the parent it can snap to this object -- `LV_OBJ_FLAG_PRESS_LOCK` Keep the object pressed even if the press slid from the object -- `LV_OBJ_FLAG_EVENT_BUBBLE` Propagate the events to the parent too -- `LV_OBJ_FLAG_GESTURE_BUBBLE` Propagate the gestures to the parent -- `LV_OBJ_FLAG_ADV_HITTEST` Allow performing more accurate hit (click) test. E.g. accounting for rounded corners -- `LV_OBJ_FLAG_IGNORE_LAYOUT` Make the object positionable by the layouts -- `LV_OBJ_FLAG_FLOATING` Do not scroll the object when the parent scrolls and ignore layout -- `LV_OBJ_FLAG_OVERFLOW_VISIBLE` Do not clip the children's content to the parent's boundary - -- `LV_OBJ_FLAG_LAYOUT_1` Custom flag, free to use by layouts -- `LV_OBJ_FLAG_LAYOUT_2` Custom flag, free to use by layouts - -- `LV_OBJ_FLAG_WIDGET_1` Custom flag, free to use by widget -- `LV_OBJ_FLAG_WIDGET_2` Custom flag, free to use by widget - -- `LV_OBJ_FLAG_USER_1` Custom flag, free to use by user -- `LV_OBJ_FLAG_USER_2` Custom flag, free to use by user -- `LV_OBJ_FLAG_USER_3` Custom flag, free to use by user -- `LV_OBJ_FLAG_USER_4` Custom flag, free to use by user - -Some examples: -```c -/*Hide on object*/ -lv_obj_add_flag(obj, LV_OBJ_FLAG_HIDDEN); - -/*Make an object non-clickable*/ -lv_obj_clear_flag(obj, LV_OBJ_FLAG_CLICKABLE); -``` - -### Groups - -Read the [Input devices overview](/overview/indev) to learn more about *Groups*. - -Objects are added to a *group* with `lv_group_add_obj(group, obj)`, and you can use `lv_obj_get_group(obj)` to see which group an object belongs to. - -`lv_obj_is_focused(obj)` returns if the object is currently focused on its group or not. If the object is not added to a group, `false` will be returned. - - -### Extended click area -By default, the objects can be clicked only within their bounding area. However, this can be extended with `lv_obj_set_ext_click_area(obj, size)`. - -## Events -- `LV_EVENT_VALUE_CHANGED` when the `LV_OBJ_FLAG_CHECKABLE` flag is enabled and the object clicked (on transition to/from the checked state) -- `LV_EVENT_DRAW_PART_BEGIN` and `LV_EVENT_DRAW_PART_END` is sent for the following types: - - `LV_OBJ_DRAW_PART_RECTANGLE` The main rectangle - - `part`: `LV_PART_MAIN` - - `rect_dsc` - - `draw_area`: the area of the rectangle - - `LV_OBJ_DRAW_PART_BORDER_POST` The border if the `border_post` style property is `true` - - `part`: `LV_PART_MAIN` - - `rect_dsc` - - `draw_area`: the area of the rectangle - - `LV_OBJ_DRAW_PART_SCROLLBAR` the scrollbars - - `part`: `LV_PART_SCROLLBAR` - - `rect_dsc` - - `draw_area`: the area of the rectangle - -Learn more about [Events](/overview/event). - -## Keys -If `LV_OBJ_FLAG_CHECKABLE` is enabled, `LV_KEY_RIGHT` and `LV_KEY_UP` make the object checked, and `LV_KEY_LEFT` and `LV_KEY_DOWN` make it unchecked. - -If `LV_OBJ_FLAG_SCROLLABLE` is enabled, but the object is not editable (as declared by the widget class), the arrow keys (`LV_KEY_UP`, `LV_KEY_DOWN`, `LV_KEY_LEFT`, `LV_KEY_RIGHT`) scroll the object. If the object can only scroll vertically, `LV_KEY_LEFT` and `LV_KEY_RIGHT` will scroll up/down instead, making it compatible with an encoder input device. See [Input devices overview](/overview/indev) for more on encoder behaviors and the edit mode. - - -Learn more about [Keys](/overview/indev). - -## Example - -```eval_rst - -.. include:: ../../examples/widgets/obj/index.rst - -``` - -## API - -```eval_rst - -.. doxygenfile:: lv_obj.h - :project: lvgl - -``` |
