PNGwriter

PNGwriter is a C++ library for creating PNG images.

Summary

PNGwriter is a very easy to use open source graphics library that uses PNG as its output format. The interface has been designed to be as simple and intuitive as possible. It supports plotting and reading pixels in the RGB (red, green, blue), HSV (hue, saturation, value/brightness) and CMYK (cyan, magenta, yellow, black) colour spaces, basic shapes, scaling, bilinear interpolation, full TrueType antialiased and rotated text support, bezier curves, opening existing PNG images and more. Documentation in English (and Spanish up to v0.5.4). Runs under Linux, Unix, Mac OS X and Windows. Requires libpng and optionally FreeType2 for the text support.

Where to find information about PNGwriter

The PNGwriter project's online presence consists of:

• The PNGwriter website, with a
• FAQ, quickstart, examples, and an online copy of the manual.
• This PNGwriter GitHub repo, where source code is distributed and collaboration takes place. The distribution includes a PDF copy of the manual.

This project was migrated from the PNGwriter repository originally hosted on SourceForge (and no longer maintained). The last version released on SourceForge was 0.5.5.

Latest News

New version and a new team member — August 2015 Update

A long time has passed since PNGwriter's last release. Thanks to the skilled and generous help of Axel Huebl (@ax3l) many bugs have been fixed, a new compilation procedure is in place, and PNGwriter is now on GitHub. Axel is now an active and invaluable member of the PNGwriter Team, joining Paul Blackburn (@individual61), who created PNGwriter in 2002. Welcome aboard, Axel!

This nudge to action could not have come at a better time, since the once-respectable host to the PNGwriter project, SourceForge.net, is no longer what we consider a positive contribution to the Open Source community. The PNGwriter website and files currently hosted on SourceForge.net will remain on SourceForge.net, but the current and all future releases will be via PNGwriter's GitHub repository. Don't forget!

Thank you, PNGwriter users, for your patience, bug fixes, and suggestions. I hope you are as excited as we are to see where the next thirteen years take PNGwriter!

Paul Blackburn
San Jose, California
August, 2015

Feedback

We'd love to hear how you've used PNGwriter in your project. Are you doing interesting things? Are you running it on interesting hardware? Tell us how you use PNGwriter. Open an issue and let us know. Don't forget to include the following information:

• Project Title
• Link
• Cool image
• Authors list
• Single-sentence, one-line description of the project.

Installation

The preferred way to install PNGwriter is using CMake:

• git clone https://github.com/pngwriter/pngwriter.git
• mkdir -p build && cd build
• cmake ../pngwriter
• make install (creates the libs in lib/ and a pngwriter.h in include/)

Optional, set a path where to install the libraries to:

• cmake -DCMAKE_INSTALL_PREFIX=~/myPath/
• make install (installs libpngwriter.a and libpngwriter.so to ~/myPath/lib/)

(There is also a pre-created Makefile shipped with the source files, but since it is not directly portable we deprecated that install method and will not support it any longer.)

Linking to your project

You can either link manually to the libpngwriter.a/libpngwriter.so (which can have dependencies to libpng, libz, libm, libc and libfreetype) or use our CMake module:

wget https://raw.githubusercontent.com/ComputationalRadiationPhysics/cmake-modules/dev/FindPNGwriter.cmake
# read its documentation
cmake -DCMAKE_MODULE_PATH=. --help-module FindPNGwriter | less

Use the following lines in your projects CMakeLists.txt:

# this example requires at least CMake 2.8.5
cmake_minimum_required(VERSION 2.8.5)

# add path to FindPNGwriter.cmake, e.g. in the directory in cmake/
set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${CMAKE_CURRENT_SOURCE_DIR}/cmake/)

# find PNGwriter installation
#   optional: prefer static libraries over shared ones (but do not force them)
#set(PNGwriter_USE_STATIC_LIBS ON)

#   optional: specifiy (minimal) version / require to find it
#           (PNGwriter 0.6.0 REQUIRED)
find_package(PNGwriter)

if(PNGwriter_FOUND)
  # where to find the pngwriter.h header file (-I include for your compiler)
  include_directories(SYSTEM ${PNGwriter_INCLUDE_DIRS})
  # additional compiler flags (e.g. -DNO_FREETYPE)
  add_definitions(${PNGwriter_DEFINITIONS})
  # libraries to link against (including dependencies)
  set(LIBS ${LIBS} ${PNGwriter_LIBRARIES})
endif(PNGwriter_FOUND)

# add_executable(yourBinary ${SOURCES})
# ...
# target_link_libraries(yourBinary ${LIBS})

License

This software is released under GPLv2+.

Changes

See the CHANGELOG.md. Please note that changes to PNGwriter prior to version 0.5.5 can be found in the doc/CHANGES file.