STM32 LVGL界面内显示DCMI摄像头视频流

/**
  * @brief  Enables DCMI DMA request and enables DCMI capture
  * @param  hdcmi     pointer to a DCMI_HandleTypeDef structure that contains
  *                    the configuration information for DCMI.
  * @param  DCMI_Mode DCMI capture mode snapshot or continuous grab.
  * @param  pData     The destination memory Buffer address (LCD Frame buffer).
  * @param  Length    The length of capture to be transferred.
  * @retval HAL status
  */
HAL_StatusTypeDef HAL_DCMI_Start_DMA(DCMI_HandleTypeDef* hdcmi, uint32_t DCMI_Mode, uint32_t pData, uint32_t Length)

lv_canvas_set_buffer(canvas, buffer, width, height, LV_IMG_CF_...)

static lv_color_t buffer[LV_CANVAS_BUF_SIZE_TRUE_COLOR(width, height)]

/**
 * @brief 设置图像输出大小
 *            OV5640输出图像的大小(分辨率),完全由该函数确定
 *            offx,offy,为输出图像在OV5640_ImageWin_Set设定窗口(假设长宽为xsize和ysize)上的偏移
 *            由于开启了scale功能,用于输出的图像窗口为:xsize-2*offx,ysize-2*offy
 *            width,height:实际输出图像的宽度和高度
 *            实际输出(width,height),是在xsize-2*offx,ysize-2*offy的基础上进行缩放处理.
 *            一般设置offx和offy的值为16和4,更小也是可以,不过默认是16和4 
 * @ret    0,设置成功
 *        其他,设置失败
*/
uint8_t OV5640_OutSize_Set(uint16_t offx,uint16_t offy,uint16_t width,uint16_t height)

// 拉伸
OV5640_OutSize_Set(300,0,240,290);

uint16_t dcmi_framebuf[240][290];

HAL_DCMI_Start_DMA(&hdcmi, DCMI_MODE_CONTINUOUS,(uint32_t)dcmi_framebuf,240*290*2/4);

// 创建对象
ui->Main_canvas_cam = lv_canvas_create(ui->Main);
// 设置buffer地址
lv_canvas_set_buffer(ui->Main_canvas_cam, dcmi_framebuf, 240, 290, LV_IMG_CF_TRUE_COLOR);
// 填充canvas背景
lv_canvas_fill_bg(ui->Main_canvas_cam, lv_color_hex(0xffffff), 255);
// 设置canvas位置
lv_obj_set_pos(ui->Main_canvas_cam, 0, 30);
// 设置canvas大小
lv_obj_set_size(ui->Main_canvas_cam, 240, 290);
// 设置canvas滚动模式
lv_obj_set_scrollbar_mode(ui->Main_canvas_cam, LV_SCROLLBAR_MODE_OFF);

HAL_DCMI_VsyncEventCallback(DCMI_HandleTypeDef *hdcmi)
{
    /// @brief 告知LVGL需要重绘对象
    /// @bug    !!!潜在BUG!!!
    ///            LVGL线程不安全，中断会频繁抢占lvgl线程
    ///     当lvgl正在刷新屏幕时被抢占调用该函数后LVGL内部会抛出Error
    ///            实际测试该问题应该不会造成内存泄露或者系统死机问题
    lv_obj_invalidate(ui.Main_canvas_cam);
}