MiniMagick¶ ↑

A ruby wrapper for ImageMagick or GraphicsMagick command line.

Tested on both Ruby 1.9.2 and Ruby 1.8.7.

Why?¶ ↑

I was using RMagick and loving it, but it was eating up huge amounts of memory. A simple script like this…

Magick::read("image.jpg") do |f|
  f.write("manipulated.jpg")
end

…would use over 100 Megs of Ram. On my local machine this wasn’t a problem, but on my hosting server the ruby apps would crash because of their 100 Meg memory limit.

Solution!¶ ↑

Using MiniMagick the ruby processes memory remains small (it spawns ImageMagick’s command line program mogrify which takes up some memory as well, but is much smaller compared to RMagick)

MiniMagick gives you access to all the commandline options ImageMagick has (Found here www.imagemagick.org/script/mogrify.php)

Examples¶ ↑

Want to make a thumbnail from a file…

image = MiniMagick::Image.open("input.jpg")
image.resize "100x100"
image.write  "output.jpg"

Want to make a thumbnail from a blob…

image = MiniMagick::Image.read(blob)
image.resize "100x100"
image.write  "output.jpg"

Got an incoming IOStream?

image = MiniMagick::Image.read(stream)

Want to make a thumbnail of a remote image?

image = MiniMagick::Image.open("http://www.google.com/images/logos/logo.png")
image.resize "5x5"
image.format "gif"
image.write "localcopy.gif"

Need to combine several options?

image = MiniMagick::Image.open("input.jpg")
image.combine_options do |c|
  c.sample "50%"
  c.rotate "-90>"
end
image.write "output.jpg"

Want to composite two images? Super easy! (Aka, put a watermark on!)

image = Image.open("original.png")
result = image.composite(Image.open("watermark.png", "jpg")) do |c|
  c.gravity "center"
end
result.write "my_output_file.jpg"

Want to manipulate an image at its source (You won’t have to write it out because the transformations are done on that file)

image = MiniMagick::Image.new("input.jpg")
image.resize "100x100"

Want to get some meta-information out?

image = MiniMagick::Image.open("input.jpg")
image[:width]               # will get the width (you can also use :height and :format)
image["EXIF:BitsPerSample"] # It also can get all the EXIF tags
image["%m:%f %wx%h"]        # Or you can use one of the many options of the format command

For more on the format command see www.imagemagick.org/script/command-line-options.php#format

Windows Users¶ ↑

When passing in a blob or IOStream, Windows users need to make sure they read the file in as binary.

#This way works on Windows
buffer = StringIO.new(File.open(IMAGE_PATH,"rb") { |f| f.read })
MiniMagick::Image.read(buffer)

#You may run into problems doing it this way
buffer = StringIO.new(File.read(IMAGE_PATH))

Using GraphicsMagick¶ ↑

Simply set

MiniMagick.processor = :gm

And you are sorted.

Requirements¶ ↑

You must have ImageMagick or GraphicsMagick installed.