Method: Magick::Image#mask

Defined in:
ext/RMagick/rmimage.cpp

#mask ⇒ Magick::Image? #mask(image) ⇒ Magick::Image?

Get/Sets an image clip mask created from the specified mask image. The mask image must have the same dimensions as the image being masked. If not, the mask image is resized to match. If the mask image has an alpha channel the opacity of each pixel is used to define the mask. Otherwise, the intensity (gray level) of each pixel is used.

In general, if the mask image does not have an alpha channel, a white pixel in the mask prevents changes to the corresponding pixel in the image being masked, while a black pixel allows changes. A pixel that is neither black nor white will allow partial changes depending on its intensity.

Overloads:

Returns:



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# File 'ext/RMagick/rmimage.cpp', line 9292

VALUE
Image_mask(int argc, VALUE *argv, VALUE self)
{
    VALUE mask;
    Image *image;

    image = rm_check_destroyed(self);
    if (argc == 0)
    {
        return get_image_mask(image);
    }
    if (argc > 1)
    {
        rb_raise(rb_eArgError, "wrong number of arguments (expected 0 or 1, got %d)", argc);
    }

    rb_check_frozen(self);
    mask = argv[0];
    return set_image_mask(image, mask);
}