libpng

Library for manipulating PNG images
http://www.libpng.org/pub/png/libpng.html

Current versions
1.6.34
HEAD

libpng requires the following formula to be installed:
xz 5.2.3 General-purpose data compression with high compression ratio

Reverse dependencies

The following formulae require libpng to be installed:
fox 1.6.51 Toolkit for developing Graphical User Interfaces easily.
grace 5.1.25
atpdec 1.7
sdl_image 1.2.12_7 Image file loading library
libkate 0.4.1_1 Overlay codec for multiplexed audio/video in Ogg
libsvg-cairo 0.1.6_2 SVG rendering library using Cairo
ufraw 0.22_2 Unidentified Flying RAW: RAW image processing utility
libbpg 0.9.7_1 Image format meant to improve on JPEG quality and file size
grace 5.1.25_2 WYSIWYG 2D plotting tool for X11
guetzli 1.0.1 Perceptual JPEG encoder
scale2x 3.1 Real-time graphics effect
dvdauthor 0.7.2 DVD-authoring toolset
qrencode 4.0.0 QR Code generation
pngnq 1.1_1 Tool for optimizing PNG images
neopop-sdl 0.2 NeoGeo Pocket emulator
imageworsener 1.3.2_1 Utility and library for image scaling and processing
fs-uae 2.8.3 Amiga emulator
xu4 1.0beta4+r3088 Remake of Ultima IV
teem 1.11.0 Libraries for scientific raster data
openmsx 0.14.0 MSX emulator
dosbox-x 0.801_1 DOSBox with accurate emulation and wide testing
mupen64plus 2.5 Cross-platform plugin-based N64 emulator
ffmpegthumbnailer 2.2.0_1 Create thumbnails for your video files
webalizer 2.23-08_1 Web server log file analysis
blat 36 Genomic sequence search tool
visp 3.0.1_4 Visual Servoing Platform library
devil 1.8.0_1 Cross-platform image library
jbig2dec 0.14 JBIG2 decoder and library (for monochrome documents)
libagar 1.5.0_1 Cross-platform GUI toolkit
ploticus 2.42_1 Scriptable plotting and graphing utility
apng2gif 1.8 Convert APNG animations into animated GIF format
gif2png 2.5.11 Convert GIFs to PNGs
swfmill 0.3.6 xml2swf and swf2xml processor
simutrans 120.1.3 Transport simulator
ucsc-genome-browser 338 Mirror of the UCSC Genome Browser
ome-files 0.5.0 Open Microscopy Environment (OME) File scientific image I/O library
mapcrafter 2.4_2 Minecraft map renderer
enblend-enfuse 4.2_3 Combines images that overlap
astrometry-net 0.73 Automatic identification of astronomical images
insighttoolkit 4.13.0 ITK is a toolkit for performing registration and segmentation
sumo 0.32.0 Simulation of Urban Mobility
ttfautohint 1.8.1 Auto-hinter for TrueType fonts
visp 3.1.0 Visual Servoing Platform library
grib-api 1.25.0 Encode and decode grib messages (editions 1 and 2)
scummvm 2.0.0 Graphic adventure game interpreter
argyll-cms 2.0.0_1 ICC compatible color management system
fizmo 0.8.5_1 Z-Machine interpreter
fltk 1.3.4-2 Cross-platform C++ GUI toolkit
mldonkey 3.1.6_2 OCaml/GTK client for the eDonkey P2P network
sane-backends 1.0.27_4 Backends for scanner access
leptonica 1.75.3 Image processing and image analysis library
netpbm 10.73.18 Image manipulation
chocolate-doom 3.0.0 Accurate source port of Doom
hatari 2.1.0 Atari ST/STE/TT/Falcon emulator
stella 5.1.1 Atari 2600 VCS emulator
flif 0.3 Free Loseless Image Format
s-lang 2.3.1a Library for creating multi-platform software
lensfun 0.3.2_3 Remove defects from digital images
taisei 1.2_1 Clone of Touhou Project shoot-em-up games
libgaiagraphics 0.5_4 Library supporting common-utility raster handling
opencv 3.4.1_2 Open source computer vision library
r 3.4.4 Software environment for statistical computing
pngquant 2.11.7 PNG image optimizing utility
dlib 19.10 C++ library for machine learning
dcmtk 3.6.3 OFFIS DICOM toolkit command-line utilities
synfig 1.0.2_3 Command-line renderer
openrct2 0.1.2 Open source re-implementation of RollerCoaster Tycoon 2
gdal 2.2.4 Geospatial Data Abstraction Library
mapserver 7.0.7_2 Publish spatial data and interactive mapping apps to the web
openclonk 7.0_2 Multiplayer action game
tectonic 0.1.7_3 Modernized, complete, self-contained TeX/LaTeX engine
fuse-emulator 1.5.2 Free Unix Spectrum Emulator
atari800 3.1.0 Atari 8-bit machine emulator
graphviz 2.40.1 Graph visualization software from AT&T and Bell Labs
gst-plugins-good 1.14.0_2 GStreamer plugins (well-supported, under the LGPL)
sox 14.4.2_1 SOund eXchange: universal sound sample translator
qemu 2.11.1 x86 and PowerPC Emulator
mapnik 3.0.20 Toolkit for developing mapping applications
imlib2 1.5.1 Image loading and rendering library
gegl 0.3.34 Graph based image processing framework
cairo 1.14.12 Vector graphics library with cross-device output support
freetype 2.9 Software library to render fonts
php@7.1 7.1.16_1 General-purpose scripting language
webp 1.0.0 Image format providing lossless and lossy compression for web images

Recent formula history

Mike McQuaid libpng: remove old keg_only reasons.
ilovezfs Use “squiggly” heredocs.
Viktor Szakats libpng: secure url(s)
ilovezfs libpng 1.6.34
ilovezfs libpng 1.6.32

Formula code at GitHub