def replace_column!(x, vector)
      assert_x!(x) && assert_height!(vector.length)
      for y in 0...height do
        set_pixel(x, y, vector[y])
      end
    end
def replace_column!(x, vector)
      assert_x!(x) && assert_height!(vector.length)
      for y in 0...height do
        set_pixel(x, y, vector[y])
      end
    end
Replaces a column of pixels on this canvas.
 @param [Integer] x The 0-based column index.
 @param [Array<Integer>] vector The vector of pixels to replace the column
   with.
 @return [void]