Show downloaded image

shilodrot · September 19, 2023, 8:03pm

Hi,

I want to download an image from my web server and show it on the screen. Can someone have an example of how to do it?

fbiego · June 26, 2026, 8:31pm

You can download the image to a file system on your device and use the in-built image decoders on LVGL

Another alternative is loading the image data from the server in a known format, e.g., RGB565, then using this as data for an lv_image_dsc_t object

github.com

fbiego/windows-10-mobile-lvgl/blob/c62690fe35509a2f61d058886c67ad3e276f3ce8/hal/esp32/apps/fbiego/fbiego.cpp#L140-L156


      
          MemoryStream memoryStream((uint8_t *)img_url[index].dsc.data, size, size, progressCallback);
          
          httpi.writeToStream(&memoryStream);
          
          // Timber.i("Downloaded %zu bytes to memory", memoryStream.getPosition());
          
          if (xSemaphoreTake(lvgl_mutex, portMAX_DELAY))
          {
              img_url[index].dsc.header.cf = LV_COLOR_FORMAT_RGB565;
              img_url[index].dsc.header.magic = LV_IMAGE_HEADER_MAGIC;
              img_url[index].dsc.data_size = size;
              img_url[index].dsc.header.w = w;
              img_url[index].dsc.header.h = h;
          
              lv_image_set_src(img_url[index].obj, &img_url[index].dsc);
              t = millis() - t;
              Timber.i("Shown image: Load time %zums ", t);