add ruby-vips-centos6

though it doesn't actually work right now

Author: jcupitt

ruby-vips-centos6/Dockerfile

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+FROM centos:6
+
+# general build stuff
+RUN yum update -y \
+	&& yum groupinstall -y "Development Tools" \
+	&& yum install -y wget tar
+
+# have to build our own ruby since centos6 ships with ruby1.8 and ruby-vips
+# needs 1.9+
+
+# stuff for a ruby build
+RUN yum install -y \
+	libxslt-devel \
+	libyaml-devel \
+	libxml2-devel \
+	gdbm-devel\
+	libffi-devel \
+	zlib-devel \
+	openssl-devel \
+	libyaml-devel \
+	readline-devel\
+	curl-devel \
+	openssl-devel \
+	pcre-devel git \
+	memcached-devel \
+	valgrind-devel \
+	mysql-devel 
+
+# stuff we need to build our own libvips ... this is a pretty random selection
+# of dependencies, you'll want to adjust these
+RUN yum install -y \
+	libpng-devel \
+	glib2-devel \
+	libjpeg-devel \
+	expat-devel \
+	zlib-devel \
+	openjpeg-devel \
+	libtiff-devel \
+	gdk-pixbuf2-devel \
+	sqlite-devel \
+	cairo-devel 
+
+# build latest ruby by default
+ARG RUBY_VERSION=2.5.1
+ARG RUBY_URL=https://cache.ruby-lang.org/pub/ruby/2.5
+
+RUN cd /usr/local/src \
+	&& wget ${RUBY_URL}/ruby-${RUBY_VERSION}.tar.gz \
+	&& tar xzf ruby-${RUBY_VERSION}.tar.gz \
+	&& cd ruby-${RUBY_VERSION} \
+	&& ./configure \
+	&& make \
+	&& make install
+
+ARG VIPS_VERSION=8.6.3
+ARG VIPS_URL=https://github.com/jcupitt/libvips/releases/download
+
+RUN cd /usr/local/src \
+	&& wget ${VIPS_URL}/v${VIPS_VERSION}/vips-${VIPS_VERSION}.tar.gz \
+	&& tar xzf vips-${VIPS_VERSION}.tar.gz \
+	&& cd vips-${VIPS_VERSION} \
+	&& ./configure \
+	&& make \
+	&& make install
+
+# install the gem
+RUN yum install -y \
+	ruby \
+	rubygems
+RUN gem install ruby-vips
+
+WORKDIR /data

ruby-vips-centos6/README.md

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+# Make a php-vips / nginx / ubuntu 16.04 stack
+
+This doesn't work at the moment -- looks like glib 2.28.4 (the centos glib) is 
+too old, perhaps?
+
+# Rebuild the image
+
+	docker pull centos:6
+
+	docker build -t ruby-vips-centos6 .
+
+# Run the demo
+
+	docker run --rm -t \
+		-v $PWD:/data \
+		ruby-vips-centos6 \
+		./wobble.rb test.jpg x.jpg
+

ruby-vips-centos6/test.jpg

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+#!/usr/bin/env ruby
+
+require 'vips'
+
+image = Vips::Image.new_from_file ARGV[0]
+
+module Vips
+    class Image
+        def wobble
+            # this makes an image where pixel (0, 0) (at the top-left) has 
+            # value [0, 0], and pixel (image.width - 1, image.height - 1) at the 
+            # bottom-right has value [image.width - 1, image.height - 1]
+            index = Vips::Image.xyz width, height 
+
+            # make a version with (0, 0) at the centre, negative values up 
+            # and left, positive down and right
+            centre = index - [width / 2, height / 2]
+
+            # to polar space, so each pixel is now distance and angle in degrees
+            polar = centre.polar
+
+            # scale sin(distance) by 1/distance to make a wavey pattern
+            d = ((polar[0] * 3).sin * 10000) / (polar[0] + 1)
+
+            # and back to rectangular coordinates again to make a set of 
+            # vectors we can apply to the original index image
+            index += d.bandjoin(polar[1]).rect
+
+            # finally, use our modified index image to distort!
+            mapim index 
+        end
+    end
+end
+
+image = image.wobble
+image.write_to_file ARGV[1]