Displaying Images (GNU Octave (version 9.1.0))

Display a matrix as an indexed color image.

The elements of img are indices into the current colormap.

x and y are optional 2-element vectors, [min, max], which specify the coordinates of the centers of the corner pixels. If a range is specified as [max, min] then the image will be reversed along that axis. For convenience, x and y may be specified as N-element vectors matching the length of the data in img. However, only the first and last elements will be used to determine the axis limits.

Multiple property/value pairs may be specified for the image object, but they must appear in pairs.

The optional return value h is a graphics handle to the image.

Implementation Note: The origin (0, 0) for images is located in the upper left. For ordinary plots, the origin is located in the lower left. Octave handles this inversion by plotting the data normally, and then reversing the direction of the y-axis by setting the ydir property to "reverse". This has implications whenever an image and an ordinary plot need to be overlaid. The recommended solution is to display the image and then plot the reversed ydata using, for example, flipud (ydata).

Calling Forms: The image function can be called in two forms: High-Level and Low-Level. When invoked with normal options, the High-Level form is used which first calls newplot to prepare the graphic figure and axes. When the only inputs to image are property/value pairs the Low-Level form is used which creates a new instance of an image object and inserts it in the current axes.

Graphic Properties: The full list of properties is documented at Image Properties.

See also: imshow, imagesc, colormap.