GNU Image Manipulation Program Formula was removed
Last versions were
gimp requires the following formulae to be installed:
pkg-config 0.29.2 Manage compile and link flags for libraries
gettext GNU internationalization (i18n) and localization (l10n) library
intltool 0.51.0 String tool
babl 0.1.44 Dynamic, any-to-any, pixel format translation library
fontconfig 2.12.6 XML-based font configuration API for X Windows
pango 1.40.14 Framework for layout and rendering of i18n text
gtk-mac-integration 2.0.8_1 Integrates GTK macOS applications with the Mac desktop
cairo 1.14.12 Vector graphics library with cross-device output support
pygtk 2.24.0_1 GTK+ bindings for Python
glib 2.54.3 Core application library for C
gdk-pixbuf 2.36.11 Toolkit for image loading and pixel buffer manipulation
freetype 2.9 Software library to render fonts
xz 5.2.3 General-purpose data compression with high compression ratio
dbus 1.12.4 Message bus system, providing inter-application communication
aalib 1.4rc5_1 Portable ASCII art graphics library
librsvg 2.42.2 Library to render SVG files using Cairo
libpng 1.6.34 Library for manipulating PNG images
libwmf Library for converting WMF (Window Metafile Format) files
libtiff 4.0.9_2 TIFF library and utilities
ghostscript 9.22 Interpreter for PostScript and PDF
poppler 0.62.0 PDF rendering library (based on the xpdf-3.0 code base)
libexif 0.6.21 EXIF parsing library

Recent formula history

Anastasia Sulyagina gimp: migrate to Homebrew Cask.
Uladzislau Shablinski gimp: revision for dbus rename
Viktor Szakats gimp: use secure urls
Dominyk Tiller gimp: vendor gegl02
Tom Schoonjans gimp 2.8.16

Formula code at GitHub