TextMate command to reset the dimensions in a HTML IMG element

gistfile1.rb

#!/usr/bin/env ruby -w

# This TextMate command takes an HTML IMG element and re-calculates its size.
# The currently selected image will then get the original dimensions.
# This is useful when you have changed an image and need to reset its dimensions
# in your HTML.
#
# This should work on the selected text or current line and replace the current
# selection. Scope: text.html. Assign a nice keyboard shortcut of your choosing.
#
# I'm sure this might be done easier or quicker, but for now, this works.
#
# Author: Arjan van der Gaag
# E-mail: info@agwebdesign.nl
# Date: 23 feb 2009
# Version: 1.0
#
# Licensed under the MIT license.

#################################################################################

# Exit the current script with a tool tip, rather
# than replacing the current selection as should be default.
def exit_show_tool_tip(msg)
	puts msg
	exit 206 # forces TextMate to output as tooltip
end

# Scan an HTML img element for its SRC, WIDTH and HEIGHT attributes.
# All three attribute values are returned.
def get_properties_for(img)
	image = img.scan(/src="(.+?)"/)[0][0]
	width = img.scan(/width="(\d+?)"/)[0][0]
	height = img.scan(/height="(\d+?)"/)[0][0]
	return image, width, height
rescue NoMethodError
	exit_show_tool_tip 'No proper image found.'
end

# Invoke sips to try and find the image's original dimensions
# This returns both the widht and height.
def get_original_size_for(image)
	output = %x{sips -g pixelWidth -g pixelHeight "#{image}"}
	if output.scan(/pixelWidth:[^\d]*(\d+).*pixelHeight:[^\d](\d+)/im)
		return $1, $2
	else
		exit_show_tool_tip "Could not get image size from #{output.inspect}"
	end
end

def reformat_images(text)
	# find our image in the current line
	if text =~ /<img(.+?)\/>/
		
		img = $1
		
		# then find its properties
		image, width, height = get_properties_for(img)
		
		# try to re-calculate the image dimensions
		new_width, new_height = get_original_size_for(image)
		
		# If they don't match we rewrite them
		if new_width != width || new_height != height
			new_img = img.gsub("width=\"#{width}\"", "width=\"#{new_width}\"").gsub("height=\"#{height}\"", "height=\"#{new_height}\"")
			return text.gsub(img, new_img)
		else
			exit_show_tool_tip 'Nothing changed'
		end
	else
		exit_show_tool_tip 'No image found.'
	end
end

print reformat_images(STDIN.read)