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# Copyright (c) 2004 Keisuke Minami
# License: Ruby's
# http://raa.ruby-lang.org/project/image_size/
class ImageSize
# Image Type Constants
module Type
OTHER = "OTHER"
GIF = "GIF"
PNG = "PNG"
JPEG = "JPEG"
BMP = "BMP"
PPM = "PPM" # PPM is like PBM, PGM, & XV
PBM = "PBM"
PGM = "PGM"
# XV = "XV"
XBM = "XBM"
TIFF = "TIFF"
XPM = "XPM"
PSD = "PSD"
PCX = "PCX"
SWF = "SWF"
end
JpegCodeCheck = [
"\xc0", "\xc1", "\xc2", "\xc3",
"\xc5", "\xc6", "\xc7",
"\xc9", "\xca", "\xcb",
"\xcd", "\xce", "\xcf",
]
# image type list
def ImageSize.type_list
Type.constants
end
# receive image & make size
# argument is image String or IO
def initialize(img_data, img_type = nil)
@img_data = img_data.dup
@img_wedth = nil
@img_height = nil
if @img_data.is_a?(IO)
@img_top = @img_data.read(512)
@img_data.seek(0, 0)
# define Singleton-method definition to IO (byte, offset)
def @img_data.read_o(length = 1, offset = nil)
self.seek(offset, 0) if offset
ret = self.read(length)
raise "cannot read!!" unless ret
ret
end
elsif @img_data.is_a?(String)
@img_top = @img_data[0, 512]
# define Singleton-method definition to String (byte, offset)
def @img_data.read_o(length = 1, offset = nil)
@img_offset = 0 if !(defined?(@img_offset))
@img_offset = offset if offset
ret = self[@img_offset, length]
@img_offset += length
ret
end
else
raise "argument class error!! #{img_data.type}"
end
if img_type.nil?
@img_type = check_type()
else
match = false
Type.constants.each do |t|
match = true if img_type == t
end
raise("img_type is failed. #{img_type}\n") if match == false
@img_type = img_type
end
eval("@img_width, @img_height = measure_" + @img_type + "()") if @img_type != Type::OTHER
end
# get parameter
def get_type; @img_type; end
def get_height
if @img_type == Type::OTHER then nil else @img_height end
end
def get_width
if @img_type == Type::OTHER then nil else @img_width end
end
def get_size
if get_height && get_width
{:width => get_width, :height => get_height}
else
nil
end
end
def mime_type
case @img_type
when 'SWF'
ret = 'application/x-shockwave-flash'
when 'PBM'
ref = 'image/x-portable-bitmap'
when 'PGM'
ret = 'image/x-portable-graymap'
when 'PPM'
ret = 'image/x-portable-pixmap'
when 'XBM'
ret = 'image/x-xbitmap'
when 'XPM'
ret = 'image/x-xpixmap'
when 'GIF', 'PNG', 'JPEG', 'BMP', 'TIFF'
ret = "image/#{@img_type.downcase}"
else
ret = 'application/octet-stream'
end
ret
end
def check_type()
if /<\s*[a-z]+/i =~ @img_top then Type::OTHER # html?
elsif @img_top =~ /^GIF8[7,9]a/ then Type::GIF
elsif @img_top[0, 8] == "\x89PNG\x0d\x0a\x1a\x0a" then Type::PNG
elsif @img_top[0, 2] == "\xFF\xD8" then Type::JPEG
elsif @img_top[0, 2] == 'BM' then Type::BMP
elsif @img_top =~ /^P[1-7]/ then Type::PPM
elsif @img_top =~ /\#define\s+\S+\s+\d+/ then Type::XBM
elsif @img_top[0, 4] == "MM\x00\x2a" then Type::TIFF
elsif @img_top[0, 4] == "II\x2a\x00" then Type::TIFF
elsif @img_top =~ /\/\* XPM \*\// then Type::XPM
elsif @img_top[0, 4] == "8BPS" then Type::PSD
elsif @img_top[0, 3] == "FWS" then Type::SWF
elsif @img_top[0] == 10 then Type::PCX
else Type::OTHER
end
end
private(:check_type)
def measure_GIF()
@img_data.read_o(6)
@img_data.read_o(4).unpack('vv')
end
private(:measure_GIF)
def measure_PNG()
@img_data.read_o(12)
raise "This file is not PNG." unless @img_data.read_o(4) == "IHDR"
@img_data.read_o(8).unpack('NN')
end
private(:measure_PNG)
def measure_JPEG()
c_marker = "\xFF" # Section marker.
@img_data.read_o(2)
while(true)
marker, code, length = @img_data.read_o(4).unpack('aan')
raise "JPEG marker not found!" if marker != c_marker
if JpegCodeCheck.include?(code)
height, width = @img_data.read_o(5).unpack('xnn')
return([width, height])
end
@img_data.read_o(length - 2)
end
end
private(:measure_JPEG)
def measure_BMP()
@img_data.read_o(26).unpack("x18VV");
end
private(:measure_BMP)
def measure_PPM()
header = @img_data.read_o(1024)
header.gsub!(/^\#[^\n\r]*/m, "")
header =~ /^(P[1-6])\s+?(\d+)\s+?(\d+)/m
width = $2.to_i; height = $3.to_i
case $1
when "P1", "P4" then @img_type = "PBM"
when "P2", "P5" then @img_type = "PGM"
when "P3", "P6" then @img_type = "PPM"
# when "P7"
# @img_type = "XV"
# header =~ /IMGINFO:(\d+)x(\d+)/m
# width = $1.to_i; height = $2.to_i
end
[width, height]
end
private(:measure_PPM)
alias :measure_PGM :measure_PPM
private(:measure_PGM)
alias :measure_PBM :measure_PPM
private(:measure_PBM)
def measure_XBM()
@img_data.read_o(1024) =~ /^\#define\s*\S*\s*(\d+)\s*\n\#define\s*\S*\s*(\d+)/mi
[$1.to_i, $2.to_i]
end
private(:measure_XBM)
def measure_XPM()
width = height = nil
while(line = @img_data.read_o(1024))
if line =~ /"\s*(\d+)\s+(\d+)(\s+\d+\s+\d+){1,2}\s*"/m
width = $1.to_i; height = $2.to_i
break
end
end
[width, height]
end
private(:measure_XPM)
def measure_PSD()
@img_data.read_o(26).unpack("x14NN")
end
private(:measure_PSD)
def measure_TIFF()
endian = if (@img_data.read_o(4) =~ /II\x2a\x00/o) then 'v' else 'n' end
# 'v' little-endian 'n' default to big-endian
packspec = [
nil, # nothing (shouldn't happen)
'C', # BYTE (8-bit unsigned integer)
nil, # ASCII
endian, # SHORT (16-bit unsigned integer)
endian.upcase, # LONG (32-bit unsigned integer)
nil, # RATIONAL
'c', # SBYTE (8-bit signed integer)
nil, # UNDEFINED
endian, # SSHORT (16-bit unsigned integer)
endian.upcase, # SLONG (32-bit unsigned integer)
]
offset = @img_data.read_o(4).unpack(endian.upcase)[0] # Get offset to IFD
ifd = @img_data.read_o(2, offset)
num_dirent = ifd.unpack(endian)[0] # Make it useful
offset += 2
num_dirent = offset + (num_dirent * 12); # Calc. maximum offset of IFD
ifd = width = height = nil
while(width.nil? || height.nil?)
ifd = @img_data.read_o(12, offset) # Get first directory entry
break if (ifd.nil? || (offset > num_dirent))
offset += 12
tag = ifd.unpack(endian)[0] # ...and decode its tag
type = ifd[2, 2].unpack(endian)[0] # ...and the data type
# Check the type for sanity.
next if (type > packspec.size + 0) || (packspec[type].nil?)
if tag == 0x0100 # Decode the value
width = ifd[8, 4].unpack(packspec[type])[0]
elsif tag == 0x0101 # Decode the value
height = ifd[8, 4].unpack(packspec[type])[0]
end
end
raise "#{if width.nil? then 'width not defined.' end} #{if height.nil? then 'height not defined.' end}" if width.nil? || height.nil?
[width, height]
end
private(:measure_TIFF)
def measure_PCX()
header = @img_data.read_o(128)
head_part = header.unpack('C4S4')
width = head_part[6] - head_part[4] + 1
height = head_part[7] - head_part[5] + 1
[width, height]
end
private(:measure_PCX)
def measure_SWF()
header = @img_data.read_o(9)
raise("This file is not SWF.") unless header.unpack('a3')[0] == 'FWS'
bit_length = Integer("0b#{header.unpack('@8B5')}")
header << @img_data.read_o(bit_length*4/8+1)
str = header.unpack("@8B#{5+bit_length*4}")[0]
last = 5
x_min = Integer("0b#{str[last,bit_length]}")
x_max = Integer("0b#{str[(last += bit_length),bit_length]}")
y_min = Integer("0b#{str[(last += bit_length),bit_length]}")
y_max = Integer("0b#{str[(last += bit_length),bit_length]}")
width = (x_max - x_min)/20
height = (y_max - y_min)/20
[width, height]
end
private(:measure_PCX)
end
if __FILE__ == $0
print "TypeList: #{ImageSize.type_list.inspect}\n"
ARGV.each do |file|
print "#{file} (string)\n"
open(file, "rb") do |fh|
img = ImageSize.new(fh)
print <<-EOF
type: #{img.get_type.inspect}
width: #{img.get_width.inspect}
height: #{img.get_height.inspect}
EOF
end
end
end
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