17.4. PNG decode

17.4.1. Overview

PNG decoding example project demonstrates how to decode a PNG file using LODEPNG software PNG library.

17.4.2. Board Setting

  • Connect the USB disk to the development board usb0 (Attention: The Cluster Size of the USB disk can’t exceed 32KB, it is recommended that the format parameter is FAT32/32KB), or insert the SD memory card into the development board SD card

    UDisk_Format

  • Connect LCD screen to development board

17.4.3. Configuration

  • File CMakeLists.txt.

    • set (PNG_USE_SDCARD 1) to read png file (.png) from SD card or set (PNG_USE_UDISK 1) to read png file (.png) from u-disk. These options are exclusive.

17.4.4. Supported picture formats

  • Supports standard PNG images

17.4.5. Image size supported by this routine

  • png file size is expected to be less than 1MB

17.4.6. Running the example

  • Configure storage in CMakeLists.txt, default is PNG_USE_SDCARD.

  • Put png files (with .png) into target storage

  • Connect LCD pannel and storage to board

  • Power on the board

  • Download built elf into development board and run the demo

  • If everything goes well, jpeg files stored in the target storage will be show on LCD pannel one by one.