FreeMat: IMAGE Image Display Function

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IMAGE Image Display Function

Section: Handle-Based Graphics

# Usage

The `image` command has the following general syntax

      handle = image(x,y,C,properties...)

where `x` is a two vector containing the `x` coordinates of the first and last pixels along a column, and `y` is a two vector containing the `y` coordinates of the first and last pixels along a row. The matrix `C` constitutes the image data. It must either be a scalar matrix, in which case the image is colormapped using the `colormap` for the current figure. If the matrix is `M x N x 3`, then `C` is intepreted as RGB data, and the image is not colormapped. The `properties` argument is a set of `property/value` pairs that affect the final image. You can also omit the `x` and `y`,

      handle = image(C, properties...)

in which case they default to `x = [1,size(C,2)]` and `y = [1,size(C,1)]`. Finally, you can use the `image` function with only formal arguments

      handle = image(properties...)

To support legacy FreeMat code, you can also use the following form of `image`

      image(C, zoomfactor)

which is equivalent to `image(C)` with the axes removed so that the image takes up the full figure window, and the size of the figure window adjusted to achieve the desired zoom factor using the `zoom` command.

# Example

In this example, we create an image that is `512 x 512` pixels square, and set the background to a noise pattern. We set the central `128 x 256` pixels to be white.

    --> x = rand(512);
    --> x((-64:63)+256,(-128:127)+256) = 1.0;
    --> figure

    ans =
     1

    --> image(x)
    --> colormap(gray)

The resulting image looks like:

Here is an example of an RGB image

    --> t = linspace(0,1);
    --> red = t'*t;
    --> green = t'*(t.^2);
    --> blue = t'*(0*t+1);
    --> A(:,:,1) = red;
    --> A(:,:,2) = green;
    --> A(:,:,3) = blue;
    --> image(A);

The resulting image looks like: