LVGL objects are created and manipulated using the 'lvgl' functions.
Most of these functions follow the syntax below. A few function have only the optional 'parent' parameter.
| Parameter | Notes | Description |
|---|---|---|
Most of the functions return an LVGL object that can be used to update the UI or in other API calls.
API functions can also be called using Lua OO syntax.
For example the following two lines are equivalent.
There are a number of settings that are common to all of the LVGL functions that take a 'settings' table parameter.
| Name | Type | Description | Default if not set |
|---|---|---|---|
The functions associated with settings are called periodically by the firmware. Where a setting is defined using a function, the UI will automatically update whenever the function returns a different value.
Although width and height, and the size function, can be defined for all objects they may not be used in some cases. For example when creating a circle or arc object the radius property should be used instead.
parent
Optional (with some exceptions) If present must be an LVGL object
Parent object. If set then whatever LVGL objects are created by the function are set as children of 'parent'. If not set then objects are created in the top level script window.
settings
Mandatory (with some exceptions) Must be a table
Contains all of the settings required to create the LVGL object.
x
Number
Horizontal position of the object relative to the top left corner of the parent object.
0
y
Number
Vertical position of the object relative to the top left corner of the parent object.
0
w
Number
Width of the object
Auto size to fit content
h
Number
Height of the object
Auto size to fit content
color
Color or Function
Primary color for the object.
COLOR_THEME_SECONDARY1
pos
Function
Position of the object relative to the top left corner of the script window. Must return a table with two values - x, y.
nil
size
Function
Size of the object. Must return a table with two values - width, height.
nil
visible
Function
Controls visibility of the object. Must return a boolean - true if the object is shown, false to hide it.
nil