The ECN No Name Newsletter is no longer being published. This is an archived issue.

ImageMagick: Digital Image Manipulation

ImageMagick is a freely-distributed collection of image modification tools available for most UNIX variants, including Linux. There are also versions available for Windows NT, Macintosh and VMS. This software is standard on most UNIX machines serving Engineering and is part of the Common UNIX Environment (CUE) set up by the ECN and the PUCC.

Information about ImageMagick is available on the Engineering web. The URL's are:
http://www.ecn.purdue.edu/ECN/Documents/Magick/
  and

http://www.ecn.purdue.edu/ECN/Newsletters/1995.May/

The basics for using ImageMagick:

1. To begin, a digital image format is necessary. One method for achieving this is scanning in the image. Image scanners are available at no charge to Purdue students, staff and faculty in LAEB Mac and PC labs. Scanners are also available for pay at some off-campus businesses. Save your image as a TIFF. This format will save the most amount of information, and permits conversion to other formats (see step #4).
2. Move the image file to your account. Use FTP from an internet-connected computer. Remember to switch to binary! Moving the file as ASCII corrupts the image.
3. To start ImageMagick, add to your path
   /usr/local/bin/magick and then type
   display file.tiff from the command line. If ImageMagick is not in your path, it will be necessary for you to call the package from the command line by typing:
   /usr/local/bin/magick/display file.tiff .
4. Reformatting Files
   One of the first things you will want to do to your image is to change the file format. While the TIFF format is best to scan with, TIFF's are not the most practical to store because they take up too much space. This could result in exceeding your account quota.

   3 Click anywhere on the image with the left mouse button to bring up a menu for editing your image. Select file then save. At the bottom of the next screen, select format. A new dialog box will appear listing formats. Select GIF or JPEG and double click, then select save. Your TIFF file has been reformatted to a GIF or JPEG file, which takes much less space and is accepted by most browsers. This action does not delete the original TIFF file. To save storage space, remove the TIFF file.

   

5. Resizing Files
   You may want to resize your image. This is done via the main menu. Go to View and then to any of the resizing options. When using the Resize option, you may change one of the numbers and the other will change itself to keep the correct height to width ratio. You can change the ratio by changing both numbers to whatever you wish and then adding a "!" at the end of the line.

   

6. Three useful image altering commands are flip, flop, and rotate. These commands are all found within the Transform button on the main menu.

   

   

   Other ImageMagick commands include:

   	Crop		Chop		Cut		Size 
   	Shear		Spiff		Dull		Equalize	
   	Normalize	Negate		Grayscale	Quantize	
   	Despeckle	Sharpen		Blur		Edge 
   	Detect		Emboss		Oil Paint	Raise	
   	Segment		Annotate	Draw		Color
   	Mat		Hue		Saturation	Brightness	
   	Gamma		Peak Noise	Composite 

   Borders and frames can also be added.

Placing An Image On Your Web Page

1. If you do not have a homepage, the easiest remedy is to move to your home directory on your Sun or HP workstation and type webinit . This will automatically create a public-web directory and all necessary support files for a properly operating web site. Information about webinit can be found at http://www.ecn.purdue.edu/ECN/FAQ/internet/web_authoring_and_cgi/personal.homepage/How_do_I_create_a_personal_homepage
2. After you have prepared your image, move the image into your public-web directory. Remember, you need to be sure the image file permissions are set to world readable. To accomplish this, type chmod 644 file.gif .

HTML