Note

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Lvgl Example Explanation

Overview

CanMV K230 integrates the lv_binding_micropython project, allowing users to develop graphical user interfaces (GUI) using lvgl. This example demonstrates the functionality of implementing lvgl animated image display on the CanMV development board.

Example

The example program below demonstrates how to use the lvgl library to display animated images on the CanMV development board. This example depends on some resource files. It is recommended to use the lvgl example that comes with the firmware.

from media.display import *
from media.media import *
import time, os, sys, gc
import lvgl as lv

DISPLAY_WIDTH = ALIGN_UP(1920, 16)
DISPLAY_HEIGHT = 1080

def display_init():
    # 使用hdmi作为显示输出，如果您选择的屏幕无法点亮，请参考API文档中的k230_canmv_display_module_api_manual自行配置
    Display.init(Display.LT9611, to_ide = True)
    # 初始化media管理器
    MediaManager.init()

def display_deinit():
    os.exitpoint(os.EXITPOINT_ENABLE_SLEEP)
    time.sleep_ms(50)
    # 销毁 display
    Display.deinit()
    # 释放media缓冲区
    MediaManager.deinit()

def disp_drv_flush_cb(disp_drv, area, color):
    global disp_img1, disp_img2

    if disp_drv.flush_is_last() == True:
        if disp_img1.virtaddr() == uctypes.addressof(color.__dereference__()):
            Display.show_image(disp_img1)
        else:
            Display.show_image(disp_img2)
    disp_drv.flush_ready()

def lvgl_init():
    global disp_img1, disp_img2

    lv.init()
    disp_drv = lv.disp_create(DISPLAY_WIDTH, DISPLAY_HEIGHT)
    disp_drv.set_flush_cb(disp_drv_flush_cb)
    disp_img1 = image.Image(DISPLAY_WIDTH, DISPLAY_HEIGHT, image.ARGB8888)
    disp_img2 = image.Image(DISPLAY_WIDTH, DISPLAY_HEIGHT, image.ARGB8888)
    disp_drv.set_draw_buffers(disp_img1.bytearray(), disp_img2.bytearray(), disp_img1.size(), lv.DISP_RENDER_MODE.DIRECT)

def lvgl_deinit():
    global disp_img1, disp_img2

    lv.deinit()
    del disp_img1
    del disp_img2

def user_gui_init():
    res_path = "/sdcard/examples/15-LVGL/data/"

    font_montserrat_16 = lv.font_load("A:" + res_path + "font/montserrat-16.fnt")
    ltr_label = lv.label(lv.scr_act())
    ltr_label.set_text("In modern terminology, a microcontroller is similar to a system on a chip (SoC).")
    ltr_label.set_style_text_font(font_montserrat_16,0)
    ltr_label.set_width(310)
    ltr_label.align(lv.ALIGN.TOP_MID, 0, 0)

    font_simsun_16_cjk = lv.font_load("A:" + res_path + "font/lv_font_simsun_16_cjk.fnt")
    cz_label = lv.label(lv.scr_act())
    cz_label.set_style_text_font(font_simsun_16_cjk, 0)
    cz_label.set_text("嵌入式系统（Embedded System），\n是一种嵌入机械或电气系统内部、具有专一功能和实时计算性能的计算机系统。")
    cz_label.set_width(310)
    cz_label.align(lv.ALIGN.BOTTOM_MID, 0, 0)

    anim_imgs = [None]*4
    with open(res_path + 'img/animimg001.png','rb') as f:
        anim001_data = f.read()

    anim_imgs[0] = lv.img_dsc_t({
    'data_size': len(anim001_data),
    'data': anim001_data
    })
    anim_imgs[-1] = anim_imgs[0]

    with open(res_path + 'img/animimg002.png','rb') as f:
        anim002_data = f.read()

    anim_imgs[1] = lv.img_dsc_t({
    'data_size': len(anim002_data),
    'data': anim002_data
    })

    with open(res_path + 'img/animimg003.png','rb') as f:
        anim003_data = f.read()

    anim_imgs[2] = lv.img_dsc_t({
    'data_size': len(anim003_data),
    'data': anim003_data
    })

    animimg0 = lv.animimg(lv.scr_act())
    animimg0.center()
    animimg0.set_src(anim_imgs, 4)
    animimg0.set_duration(2000)
    animimg0.set_repeat_count(lv.ANIM_REPEAT_INFINITE)
    animimg0.start()

def main():
    os.exitpoint(os.EXITPOINT_ENABLE)
    try:
        display_init()
        lvgl_init()
        user_gui_init()
        while True:
            time.sleep_ms(lv.task_handler())
    except BaseException as e:
        print(f"Exception {e}")
    lvgl_deinit()
    display_deinit()
    gc.collect()

if __name__ == "__main__":
    main()

Tip

For specific interface definitions, please refer to lvgl