Method: Vips::Image.new_from_array

Defined in:
lib/vips8/image.rb

.new_from_array(array, scale = 1, offset = 0) ⇒ Image

Create a new Image from a 1D or 2D array. A 1D array becomes an image with height 1. Use scale and offset to set the scale and offset fields in the header. These are useful for integer convolutions.

For example:

image = Vips::new_from_array [1, 2, 3]

or

image = Vips::new_from_array [
    [-1, -1, -1],
    [-1, 16, -1],
    [-1, -1, -1]], 8

for a simple sharpening mask.

Parameters:

  • array (Array) —

    the pixel data as an array of numbers

  • scale (Real) (defaults to: 1) —

    the convolution scale

  • offset (Real) (defaults to: 0) —

    the convolution offset

Returns:

[View source]

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# File 'lib/vips8/image.rb', line 499

def self.new_from_array(array, scale = 1, offset = 0)
    # we accept a 1D array and assume height == 1, or a 2D array
    # and check all lines are the same length
    if not array.is_a? Array
        raise Vips::Error, "Argument is not an array."
    end

    if array[0].is_a? Array
        height = array.length
        width = array[0].length
        if not array.all? {|x| x.is_a? Array}
            raise Vips::Error, "Not a 2D array."
        end
        if not array.all? {|x| x.length == width}
            raise Vips::Error, "Array not rectangular."
        end
        array = array.flatten
    else
        height = 1
        width = array.length
    end

    if not array.all? {|x| x.is_a? Numeric}
        raise Vips::Error, "Not all array elements are Numeric."
    end

    image = Vips::Image.matrix_from_array width, height, array
    if image == nil
        raise Vips::Error
    end

    # be careful to set them as double
    image.set_double 'scale', scale.to_f
    image.set_double 'offset', offset.to_f

    return image
end