==========================
UEFI Display/Inputs driver
==========================

Overview
--------

The **UEFI** display/input `driver <https://github.com/lvgl/lvgl/src/drivers/uefi>`__ offers support for using LVGL with UEFI.

Prerequisites
-------------

You need the following protocols available:

* *EFI_LOADED_IMAGE_PROTOCOL_GUID*, for file system support (used to determine the file system that was used to load the application)
* *EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID*, for file system support
* *EFI_SIMPLE_TEXT_INPUT_EX_PROTOCOL_GUID*, for keyboard support
* *EFI_SIMPLE_POINTER_PROTOCOL_GUID*, for mouse support
* *EFI_ABSOLUTE_POINTER_PROTOCOL_GUID*, for touch support
* *EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID*, for drawing
* *EFI_EDID_ACTIVE_PROTOCOL_GUID*, for drawing (optional)

Configure UEFI driver
------------------------

- Enable the UEFI driver support in lv_conf.h

.. code-block:: c

    #define LV_USE_UEFI  1

- Enable the memory core functions, which are wrappers around AllocatePool and FreePool (using memory of type *EfiBootServicesData*) if you do not wan't to use your own implementations

.. code-block:: c

    #define LV_UEFI_USE_MEMORY_SERVICES  1

- You can enable file system support for the file system from which the application got loaded (default letter 'E')

.. code-block:: c

    #define LV_USE_FS_UEFI  1

- You need to define an include file which contains the basic UEFI definitions (protocols and types), there are 2 predefined files which can be used for EDK2 and gnu-efi

.. code-block:: c

    #define LV_USE_UEFI_INCLUDE <lvgl/src/drivers/uefi/lv_uefi_edk2.h>
    // or
    #define LV_USE_UEFI_INCLUDE <lvgl/src/drivers/uefi/lv_uefi_gnu_efi.h>

Usage
-----

.. code-block:: c

    #include "lvgl/lvgl.h"
    #include "lvgl/examples/lv_examples.h"
    #include "lvgl/demos/lv_demos.h"

    EFI_STATUS EFIAPI EfiMain(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE * SystemTable)
    {
        lv_uefi_init(ImageHandle, SystemTable);
        lv_init();

        if(!lv_is_initialized()) return EFI_NOT_READY;

        EFI_HANDLE handle = NULL;
        lv_display_t* display = NULL;
        lv_indev_t* indev = NULL;
        lv_group_t* group = NULL;
        lv_obj_t* cursor = NULL;
        // used to get out of the main loop
        size_t counter;

        // Init the display
        handle = lv_uefi_display_get_active();
        if(handle == NULL) {
            handle = lv_uefi_display_get_any();
        }
        if(handle == NULL) {
            lv_deinit();
            return EFI_UNSUPPORTED;
        }

        display = lv_uefi_display_create(handle);
        lv_display_set_default(display);

        // Create the group
        group = lv_group_create();
        lv_group_set_default(group);

        // Create an image that can be used as cursor
        cursor = lv_image_create(lv_layer_top());
        lv_image_set_src(cursor, "E:cursor.png");

        // Create the input devices
        indev = lv_uefi_simple_text_input_indev_create();
        lv_indev_set_group(indev, lv_group_get_default());
        lv_uefi_simple_text_input_indev_add_all(indev);

        indev = lv_uefi_simple_pointer_indev_create(NULL);
        lv_uefi_simple_pointer_indev_add_all(indev);
        lv_indev_set_cursor(indev, cursor);

        indev = lv_uefi_absolute_pointer_indev_create(NULL);
        lv_uefi_absolute_pointer_indev_add_all(indev);

        lv_demo_widgets();

        // Run main loop for ~ 10 seconds
        counter = 0;
        while(counter < 10000) {
            counter ++;
            gBS->Stall(1000);
            lv_tick_inc(1);
            lv_timer_handler();
        }

        return EFI_SUCCESS;
    }
