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XHISTOGRAM

Section: C Library Functions (3)
Updated: 16 Mar 1998
Index

NAME

xhistogram - Show the histogram of an image.

SYNTAX

void xhistogram( Widget wid, IMAGE image,
    IBAND band, Colormap map, int planes,
    ximage_display_func display_func,
    image_callbacks *callbacks );

DESCRIPTION

xhistogramdisplays a histogram widget. The dispargument supplies a function which is called when the"Send image"-button is pressed, to send a histogram-manipulated image back to xshow as a new image widget. Thisdisplay function is stored in the global variable dispfunc_s.

xhistogramcalls mkHisto(3)for an unsigned byte band andmkDhistogram(3)for other pixel types.

A copy of the currently active colortable is added to theColors menu of the image. The reduced-color version in thepixel range [64..191] is changed to gray-scale, and thiscolortable becomes the active one for the histogram window, aswell as for the image window.

A special set of colors is installed in some entries outsidethe pixel range [64..191] of the colormap (in the overlaycolor entries). Some of these are used to give the correctcolors to the primary manipulating lines available when anon-Gray Mode is chosen. By insisting on a visible overlay ontop of the image, the overlay colors may therefore beincorrect.

RETURN VALUE

None

AUTHOR

Otto Milvang

REVISED

Svein Bře

DOC