# File lib/RMagick.rb, line 1014
1014:         def initialize(img, x, y, width, height)
1015:             img.check_destroyed
1016:             if width <= 0 || height <= 0
1017:                 Kernel.raise ArgumentError, "invalid geometry (#{width}x#{height}+#{x}+#{y})"
1018:             end
1019:             if x < 0 || y < 0 || (x+width) > img.columns || (y+height) > img.rows
1020:                 Kernel.raise RangeError, "geometry (#{width}x#{height}+#{x}+#{y}) exceeds image boundary"
1021:             end
1022:             @view = img.get_pixels(x, y, width, height)
1023:             @img = img
1024:             @x = x
1025:             @y = y
1026:             @width = width
1027:             @height = height
1028:             @dirty = false
1029:         end

      # File lib/RMagick.rb, line 1031
1031:         def [](*args)
1032:             rows = Rows.new(@view, @width, @height, args)
1033:             rows.add_observer(self)
1034:             return rows
1035:         end

      # File lib/RMagick.rb, line 1038
1038:         def sync(force=false)
1039:             @img.store_pixels(x, y, width, height, @view) if (@dirty || force)
1040:             return (@dirty || force)
1041:         end

      # File lib/RMagick.rb, line 1045
1045:         def update(rows)
1046:             @dirty = true
1047:             rows.delete_observer(self)      # No need to tell us again.
1048:             nil
1049:         end