def get_dimensions
         dimensions = nil

         open_file do |file|
           file.pos = DIMENSIONS_OFFSET[@type]
           read = []

           # Check the image type.
           if @type == JPEG
              # Read until we can't anymore or we've found what we're looking for.
              done = false
              while !file.eof? and !done
                 # Read to the next marker.
                 read_source(file,read) {|c| c == 0xff} # Read to the marker.
                 read_source(file,read) {|c| c != 0xff} # Skip any padding.

                 if read[-1] >= 0xc0 && read[-1] <= 0xc3
                    # Read in the width and height details.
                    read_source(file, read, 7)
                    dimensions = read[-4,4].pack('C4').unpack('nn').reverse
                    done       = true
                 else
                    # Skip the marker block.
                    read_source(file, read, 2)
                    read_source(file, read, read[-2,2].pack('C2').unpack('n')[0] - 2)
                 end
              end
           elsif @type == PNG
              # Read in the data to contain the width and height.
              read_source(file, read, 16)
              dimensions = read[-8,8].pack('C8').unpack('N2')
           elsif @type == BITMAP
              # Read in the data to contain the width and height.
              read_source(file, read, 18)
              dimensions = [to_integer(read[-8,4]), to_integer(read[-4,4])]
           end
         end

         dimensions
      end
def get_dimensions
         dimensions = nil

         open_file do |file|
           file.pos = DIMENSIONS_OFFSET[@type]
           read = []

           
           if @type == JPEG
              
              done = false
              while !file.eof? and !done
                 
                 read_source(file,read) {|c| c == 0xff} 
                 read_source(file,read) {|c| c != 0xff} 

                 if read[-1] >= 0xc0 && read[-1] <= 0xc3
                    
                    read_source(file, read, 7)
                    dimensions = read[-4,4].pack('C4').unpack('nn').reverse
                    done       = true
                 else
                    
                    read_source(file, read, 2)
                    read_source(file, read, read[-2,2].pack('C2').unpack('n')[0] - 2)
                 end
              end
           elsif @type == PNG
              
              read_source(file, read, 16)
              dimensions = read[-8,8].pack('C8').unpack('N2')
           elsif @type == BITMAP
              
              read_source(file, read, 18)
              dimensions = [to_integer(read[-8,4]), to_integer(read[-4,4])]
           end
         end

         dimensions
      end
def get_dimensions dimensions = nil open_file do | file | file . pos = DIMENSIONS_OFFSET [ @type ] read = [ ] # Check the image type. if @type == JPEG # Read until we can't anymore or we've found what we're looking for. done = false while ! file . eof? and ! done # Read to the next marker. read_source ( file , read ) { | c | c == 0xff } # Read to the marker. read_source ( file , read ) { | c | c != 0xff } # Skip any padding. if read [ - 1 ] >= 0xc0 && read [ - 1 ] <= 0xc3 # Read in the width and height details. read_source ( file , read , 7 ) dimensions = read [ - 4 , 4 ] . pack ( 'C4' ) . unpack ( 'nn' ) . reverse done = true else # Skip the marker block. read_source ( file , read , 2 ) read_source ( file , read , read [ - 2 , 2 ] . pack ( 'C2' ) . unpack ( 'n' ) [ 0 ] - 2 ) end end elsif @type == PNG # Read in the data to contain the width and height. read_source ( file , read , 16 ) dimensions = read [ - 8 , 8 ] . pack ( 'C8' ) . unpack ( 'N2' ) elsif @type == BITMAP # Read in the data to contain the width and height. read_source ( file , read , 18 ) dimensions = [ to_integer ( read [ - 8 , 4 ] ) , to_integer ( read [ - 4 , 4 ] ) ] end end dimensions end
This method fetches details of the dimensions associated with an image.
This method fetches details of the dimensions associated with an image .