+@item display_mode
+Set display mode for @code{waveform} and @code{levels}.
+It accepts the following values:
+@table @samp
+@item parade
+Display separate graph for the color components side by side in
+@code{row} waveform mode or one below other in @code{column} waveform mode
+for @code{waveform} histogram mode. For @code{levels} histogram mode
+per color component graphs are placed one bellow other.
+
+This display mode in @code{waveform} histogram mode makes it easy to spot
+color casts in the highlights and shadows of an image, by comparing the
+contours of the top and the bottom of each waveform.
+Since whites, grays, and blacks are characterized by
+exactly equal amounts of red, green, and blue, neutral areas of the
+picture should display three waveforms of roughly equal width/height.
+If not, the correction is easy to make by making adjustments to level the
+three waveforms.
+
+@item overlay
+Presents information that's identical to that in the @code{parade}, except
+that the graphs representing color components are superimposed directly
+over one another.
+
+This display mode in @code{waveform} histogram mode can make it easier to spot
+the relative differences or similarities in overlapping areas of the color
+components that are supposed to be identical, such as neutral whites, grays,
+or blacks.
+@end table
+Default is @code{parade}.
+@end table
+