apngasm-python 1.0.4

A nanobind API for apngasm, a tool/library for APNG assembly/disassembly.

apngasm-python

A nanobind API for apngasm, a tool/library for APNG assembly/disassembly.

apngasm is originally a CLI program for quickly assembling PNG images into animated PNG (APNG). It also supports creating compressed APNG.

apngasm-python is a binding for apngasm using nanobind, allowing you to use apngasm without calling it using commands.

With this module, you can even create APNG using images inside memory (No need to write them out as file and call apngasm! This is about 2 times faster from testing.)

A similar python module is https://github.com/eight04/pyAPNG , which handles APNG files with python natively and does not support compression.

For convenience, prebuilt library is packaged with this module, so you need not download apngasm.

Install

pip install apngasm-python

Example usage

The recommended usage is to from apngasm_python import APNGAsmBinder, see example/example_binder.py

from apngasm_python import APNGAsmBinder
import numpy as np
from PIL import Image
import os

apngasm = APNGAsmBinder()

# From file
for file_name in sorted(os.listdir('frames')):
    # To adjust frame duration, set delay_num and delay_den
    # The frame duration will be (delay_num / delay_den) seconds
    apngasm.add_frame_from_file(file_path=os.path.join('frames', file_name), delay_num=100, delay_den=1000)
    
# Default value of loops is 0, which is infinite looping of APNG animation
# This sets the APNG animation to loop for 3 times before stopping
apngasm.set_loops(3)
apng.assemble('result-from-file.apng')
apngasm.reset()

# From Pillow
for file_name in sorted(os.listdir('frames')):
    image = Image.open(os.path.join('frames', file_name)).convert('RGBA')
    frame = apngasm.add_frame_from_pillow(image, delay_num=50, delay_den=1000)
apngasm.assemble('result-from-pillow.apng')
apngasm.reset()

# Disassemble and get pillow image of one frame
# You can use with statement to avoid calling reset()
with APNGAsmBinder() as apng:
    frames = apng.disassemble_as_pillow('input/ball.apng')
    frame = frames[0]
    frame.save('output/ball0.png')

# Disassemble all APNG into PNGs
apngasm.save_pngs('output')

Alternatively, you can reduce overhead and do advanced tasks by calling methods directly, see example/example_direct.py

from apngasm_python.apngasm import APNGAsm, APNGFrame, create_frame_from_rgb, create_frame_from_rgba
import numpy as np
from PIL import Image
import os

apngasm = APNGAsm()

# From file
for file_name in sorted(os.listdir('frames')):
    # To adjust frame duration, set delay_num and delay_den
    # The frame duration will be (delay_num / delay_den) seconds
    apngasm.add_frame_from_file(file_path=os.path.join('frames', file_name), delay_num=100, delay_den=1000)
    
# Default value of loops is 0, which is infinite looping of APNG animation
# This sets the APNG animation to loop for 3 times before stopping
apngasm.set_loops(3)
apng.assemble('result-from-file.apng')

# From Pillow
apngasm.reset()
for file_name in sorted(os.listdir('frames')):
    image = Image.open(os.path.join('frames', file_name)).convert('RGBA')
    frame = create_frame_from_rgba(np.array(image).flatten(), image.width, image.height)
    frame.delay_num = 50
    frame.delay_den = 1000
    apngasm.add_frame(frame)
apngasm.assemble('result-from-pillow.apng')

# Disassemble and get pillow image of one frame
apngasm.reset()
frames = apngasm.disassemble('input/ball.apng')
frame = frames[0]
im = Image.frombytes(mode, (frame.width, frame.height), frame.pixels)
im.save('output/ball0.png')

# Disassemble all APNG into PNGs
apngasm.save_pngs('output')

The methods are based on apngasm.h and apngframe.h

You can get more info about the binding from src/apngasm_python.cpp, or by...

from apngasm_python import _apngasm_python
help(_apngasm_python)

Building from source

Method 1: Without vcpkg

Simply run:

git clone https://github.com/laggykiller/apngasm-python.git
cd apngasm-python
git submodule update --init --recursive

# To build wheel
python3 -m build .

# To install directly
pip3 install .

• Note that you will need CMake.
• If on Windows, you will need Visual Studio installed
• Cross-compilation not supported using this method

Method 2: With vcpkg

1. Install vcpkg: https://github.com/microsoft/vcpkg
2. Set environment variable that points to the path of vcpkg root

# On Windows (cmd, not PowerShell)
set VCPKG_INSTALLATION_ROOT=C:/path/to/vcpkg

# On *nix
export VCPKG_INSTALLATION_ROOT=/path/to/vcpkg

3. Building

git clone https://github.com/laggykiller/apngasm-python.git
cd apngasm-python
# --recursive flag not necessary here
git submodule update --init

# To build wheel
python3 -m build .

# To install directly
pip3 install .

Note that this method also support cross-compilation, to do so you will need to set environment variables beforehand:

# Choose only one

# On Windows (cmd, not PowerShell)
set APNGASM_COMPILE_TARGET=x64
set APNGASM_COMPILE_TARGET=x86
set APNGASM_COMPILE_TARGET=arm64
set APNGASM_COMPILE_TARGET=arm

# On MacOS
export APNGASM_COMPILE_TARGET=x64
export APNGASM_COMPILE_TARGET=x86
export APNGASM_COMPILE_TARGET=arm64

# On *nix
export APNGASM_COMPILE_TARGET=x64
export APNGASM_COMPILE_TARGET=x86
export APNGASM_COMPILE_TARGET=arm64

Credits

• apngasm: https://github.com/apngasm/apngasm
• Packaging: https://github.com/tttapa/py-build-cmake
• Example files:
  • https://apng.onevcat.com/demo/
  • https://commons.wikimedia.org/wiki/File:Animated_PNG_example_bouncing_beach_ball.png
  • https://commons.wikimedia.org/wiki/File:Grayscale_8bits_palette_sample_image.png
  • https://commons.wikimedia.org/wiki/File:RG_16bits_palette_sample_image.png