Modifying a copy of an image

This example copies the input image first and then modifies the copy. This is essential if the input image needs to be kept. A complete program called add.f exists (see §).

*  Access an existing image.
      CALL IMG_IN( 'IN', NX, NY, IPIN, ISTAT )

*  Create a new output image by copying the input image.
      CALL IMG_OUT( 'IN', 'OUT', IPOUT, ISTAT )               [1]

*  Modify the output image.
      CALL DOFILL( %VAL( IPOUT ), NX, NY, ISTAT )

*  Free the input and output images.
      CALL IMG_FREE( '*', ISTAT )                             [2]

The following notes refer to the numbered statements:

1.

The call to IMG_OUT creates a new output image associated with the parameter 'OUT' by copying the one associated with the parameter 'IN'. It returns a pointer IPOUT for the output image data.

2.

Notice that the names of the image parameters are not shown explicitly in this call to IMG_FREE. Using a '*' indicates that all known images should be freed.