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rubyimagermagick

Rmagick crop to same image?

I have find that when you want to crop an image in Rmagick, it doesn't mutate the current image object, but it returns a new one.

So, if I have:

@image = Magick::ImageList.new(path)
@cropped = @image.crop(10,10,20,20)

I wonder if the following code would be a good solution in terms of if I want to have always @image to contain the current image that is being manipulated.

@image = Magick::ImageList.new(path)
@image = @image.crop(10,10,20,20)

This works, but would I be having two images here? Should I destroy the first one before reassigning to @image?

Solution

  • There is an in-place version of crop called crop!:

    img.crop!(x, y, width, height) -> self
    img.crop!(gravity, x, y, width, height) -> self
    img.crop!(gravity, width, height) -> self

    The in-place form of crop.

    so you can say:

    @image = Magick::ImageList.new(path).crop!(10,10,20,20)

    if you want to avoid making a copy. Or you could let the GC deal with it and say:

    @image = Magick::ImageList.new(path).crop(10,10,20,20) # No `!` here