png2lvgl

Convert PNG images to LVGL C arrays with support for multiple color formats.

Features

• 🎨 Multiple color format support (True Color, Indexed, Alpha)
• 🚀 Fast and efficient Rust implementation
• 📦 Zero runtime dependencies in generated C code
• 🔧 Automatic format detection
• 💾 Safe file handling (no accidental overwrites)

Installation

Cargo (Recommended)

cargo install png2lvgl

Homebrew (macOS)

# Add the tap
brew tap metaneutrons/tap

# Install png2lvgl
brew install png2lvgl

Pre-built Binaries

Download the latest release for your platform from GitHub Releases.

From Source

cargo install --git https://github.com/metaneutrons/png2lvgl

Usage

# Basic usage (auto-detects format, defaults to LVGL 9.0)
png2lvgl input.png

# Target LVGL 8.x
png2lvgl input.png --lvgl-v8

# Specify output file
png2lvgl input.png -o output.c

# Use 4-bit indexed grayscale (16 colors)
png2lvgl input.png -f indexed4

# Generate big-endian RGB565 (for big-endian systems)
png2lvgl input.png -f true-color --big-endian

# Overwrite existing file
png2lvgl input.png --overwrite

LVGL Version Compatibility

png2lvgl supports both LVGL 8.x and 9.x APIs:

Default: LVGL 9.x format constants are used if no flag is specified.

Example:

# For LVGL 9.x projects (default)
png2lvgl icon.png -o ui/icon.c

# For LVGL 8.x projects
png2lvgl icon.png --lvgl-v8 -o ui/icon.c

Supported Formats

Endianness

RGB565 formats (true-color and true-color-alpha) are generated in little-endian byte order by default, which matches most embedded systems (ARM Cortex-M, ESP32, etc.).

For big-endian systems (some PowerPC, MIPS, older ARM), use the --big-endian flag:

png2lvgl input.png -f true-color --big-endian

Note: Indexed and alpha-only formats are not affected by endianness as they don't use RGB565 encoding.

Output Format

Generated C files are compatible with LVGL and include:

• Proper header guards
• Memory alignment attributes
• Color palette (for indexed formats)
• Image descriptor structure

Example output:

const lv_img_dsc_t my_image = {
  .header.cf = LV_IMG_CF_INDEXED_4BIT,
  .header.w = 540,
  .header.h = 960,
  .data_size = 259200,
  .data = my_image_map,
};

Building from Source

git clone https://github.com/metaneturons/png2lvgl
cd png2lvgl
cargo build --release

License

This project is licensed under the GNU General Public License v3.0 - see the LICENSE file for details.

Made with ❤️ in Hannover