Direct sd card image reading support for lvgl

[youkorr]

Feature Request: Direct SD Card Image Reading Support for LVGL

Summary

Add support for direct image reading from SD card in the image section to work seamlessly with LVGL on ESP32-S3 and ESP32-P4 platforms.

Description

Currently, images in ESPHome are stored in the ESP32’s flash memory, which quickly becomes a limitation when working with:

• Background wallpapers for LVGL displays
• Radio station cover art
• Dynamic image content
• Large image libraries

Proposed Feature

Enable the image component to read images directly from an SD card without consuming flash memory space on the ESP32.

Target Platforms

• ESP32-S3
• ESP32-P4

Use Cases

1. Dynamic wallpapers: Store multiple background images on SD card and switch between them
2. Radio station covers: Display album art/station logos loaded from SD card
3. Image galleries: Browse through images stored externally
4. Memory optimization: Keep flash memory available for code and essential data

Technical Requirements

• Integration with existing LVGL image handling
• Support for common image formats (PNG, JPEG, BMP)
• Efficient memory management (load on demand)
• Optional caching mechanism for frequently accessed images
• Fallback to flash-stored images when SD card is unavailable

Proposed Configuration Example

image:

  defaults:
    byte_order: little_endian
    transparency: alpha_channel
    type: rgb565
  image:
    - file: "/sd/wallpapers/background1.png"
      id: bg_image_1
      resize: 320x240
      
    - file: "/sd/radio_covers/station_logo.jpg"
      id: radio_cover
      resize: 64x64

display:
  - platform: ili9xxx  # or other LVGL-compatible display
    # ... other config
    pages:
      - id: main_page
        widgets:
          - image:
              align: CENTER
              src: bg_image_1

Benefits

• Significantly reduces flash memory usage
• Enables dynamic image content
• Supports larger image libraries
• Maintains compatibility with existing LVGL functionality
• Allows for easier content updates via SD card

Additional Considerations

• Error handling for missing SD card or corrupted files
• Performance optimization for image loading
• Integration with existing file system components
• Documentation and examples for implementation

This feature would greatly enhance the capabilities of LVGL-based projects on ESP32 platforms while addressing the critical limitation of flash memory space for image storage.

[David H (herrdivad)]

Hi youkorr,

I ran into the same issue a while ago and created a Custom Component to solve it:

https://github.com/herrdivad/ESPHomeSDCardServer

Feel free to give it a try! Since it's fairly new, I’m actively looking for feedback and testers. If you test it out, let me know how it works for you or if you run into any issues.

It provides an HTTP Webserver with a UI to upload images (and other data) and exposes entities to Home Assistant to dynamically control your images using shared RAM, even if the same image is used on different LVGL widgets. Fallback is a slower SD streaming.

Because it has some limitations and has only been tested recently on my own specific CYD hardware, your feedback would be very valuable to me!

[youkorr]

Hi, I'm delighted to be able to try it out, but I'm currently traveling abroad. I'll happily give you some feedback.