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Using Macros to Import Image Files

To import an image file into IDL using a macro, complete the following steps:

  1. Select the Import Image toolbar button. The Select Image File dialog is displayed.

    2.  

  2. Select a file to import. For example, select the IDL_DIR/examples/data/muscle.jpg file where IDL_DIR is the installation directory for IDL. See Using the Select Image File Dialog Interface under DIALOG_READ_IMAGE for additional information if desired.

    3.  

  3. Click Open.

The muscle.jpg image data has been opened into a structure variable named MUSCLE_IMAGE. The Import Image macro opens and stores image data in a structure variable named filename_IMAGE where filename is the name of the file you opened without the extension.


Note
IDL variables must begin with a letter, and may contain only letters, digits, the underscore character, or the dollar sign. If the first character of filename is not a letter, the prefix "var" is added to the variable name. Any spaces within filename are converted to underscores. Any other illegal characters within filename are removed.

The MUSCLE_IMAGE structure contains the following fields:

The structure can be viewed in the Variable Watch Window.

 

Figure 1-2: Variable Watch Window Showing MUSCLE_IMAGE Structure

Figure 1-2: Variable Watch Window Showing MUSCLE_IMAGE Structure

You can specify which part of the structure variable you want to access by using the following syntax:

variable_name.element_name[.element_name]

For example, if you want to view the image, enter the following: 

IIMAGE, MUSCLE_IMAGE.IMAGE

If you want to know the file type, enter the following: 

PRINT, MUSCLE_IMAGE.QUERY.TYPE

IDL prints: 

JPEG

  IDL Online Help (March 06, 2007)