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IMWRITE Write Matrix to Image File

Section: Input/Ouput Functions

# Usage

Write the image data from the matrix into a given file. Note that FreeMat's support for `imwrite` is not complete. You can write images in the `jpg,png,xpm,ppm` and some other formats. The syntax for its use is

      imwrite(A, filename)
      imwrite(A, map, filename)
      imwrite(A, map, filename, 'Alpha', alpha)

    or Octave-style syntax:
      imwrite(filename, A)
      imwrite(filename, A, map)
      imwrite(filename, A, map, alpha)

where `filename` is the name of the file to write to. The input array `A` contains the image data (2D for gray or indexed, and 3D for color). If `A` is an integer array (int8, uint8, int16, uint16, int32, uint32), the values of its elements should be within 0-255. If `A` is a floating-point array (float or double), the value of its elements should be in the range [0,1]. `map` contains the colormap information (for indexed images), and `alpha` the alphamap (transparency).

# Example

Here is a simple example of `imread`/`imwrite`. First, we generate a grayscale image and save it to an image file.

    --> a =  uint8(255*rand(64));
    --> figure(1), image(a), colormap(gray)
    --> title('image to save')
    --> imwrite(a, 'test.bmp')

Then, we read image file and show it:

    --> b = imread('test.bmp');
    --> figure(2), image(b), colormap(gray)
    --> title('loaded image')