分解GIF图片为PNG[怨念的产物] - Project1

=begin
脚本：【怨念产物】
功能：分解GIF图片为PNG格式。
说明: 直接用 GIF.analyze_gif 使用。
把需要分解的GIF文件放在工程下的GIF文件夹下即可，运行即可，ms速度比较慢。
作者：灼眼的夏娜
=end
=begin
GIF文件格式初步讲解：
1、文件头(6字节)：
2、逻辑屏幕标符(7字节) ：
3、[全局调色板数据] ：根据2中的GlobalFlag确定相关属性，可无。
4、[GIF扩充块]：各种扩充块，可无。
[图形控制扩充块(6字节),图形说明扩充块(13+1+),注释说明扩充块(0+1+),应用程序扩充块(12+1+)]
5、图象描述块：0x2c 开始。
6、[局部调色板]：根据5中的LocalFlag中的LocalPal可以判断有无。
7、图象数据
8、7的第一个字节为LZW编码长度
9、编码长度之后为连续的数据子块，每个数据子块长度为 0 - 256 字节。
10、数据子块的第一个字节为该子块的长度。
11、文件结尾：0x3b
=end
module GIF
# 定义常量
SIZE_GIFH = 6
SIZE_GIFS = 7
SIZE_GIFI = 9
SIZE_GIFC = 6
SIZE_GIFP = 13
SIZE_GIFA = 12
CODE_MASK = [0x0000,
0x0001,0x0003,0x0007,0x000f,
0x001f,0x003f,0x007f,0x00ff,
0x01ff,0x03ff,0x07ff,0x0fff]
INC_TABLE = [8,8,4,2,0]
BGN_TABLE = [0,4,2,1,0]
# 建立文件夹
Dir.mkdir("GIF") unless Dir["*"].include?("GIF")
# 函数定义
module_function
#--------------------------------------------------------------------------
# ● 分解gif图片
#--------------------------------------------------------------------------
def analyze_gif
@old_dir = Dir.pwd
Dir.chdir("GIF")
@total_gif = []
for g in Dir["*"]
suf = g.split(/\./)
if suf[1].is_a?(String) and suf[1].downcase == "gif"
@total_gif.push(g)
Dir.mkdir(suf[0]) unless Dir["*"].include? suf[0]
end
end
@total_gif.each{|file| self.readdata(file)}
Dir.chdir(@old_dir)
p '全部分解完毕，点击确定退出'
exit
end
#--------------------------------------------------------------------------
# ● 读取文件数据
#--------------------------------------------------------------------------
def readdata(filename)
# 初始化数据
self.initial_var(filename)
# 打开文件
begin
@f = open(filename,"rb")
# 读取文件头
self.read_gifh
# 读取逻辑屏幕描述块
self.read_gifs
# 读取下一个字节
@temp = @f.read(1)[0]
# 循环读取每个图象描述块
while true
if @temp == 0x2c
# 读取图象描述块
self.read_gifi
end
if @temp == 0x21
# 读取图象扩展块
self.read_gife
end
if @temp == 0x3b
break
end
# 读取下一个字节
@temp = @f.read(1)[0]
end
# end
p @filename + '分解完毕...'
ensure
@f.close
end
end
#--------------------------------------------------------------------------
# ● 初始化变量
#--------------------------------------------------------------------------
def initial_var(filename)
@gif_count = 0
@f = nil
@temp = nil
@filename = filename.split(/\./)[0]
@now_path = @filename + "/"
end
#--------------------------------------------------------------------------
# ● 读取文件头
#--------------------------------------------------------------------------
def read_gifh
@gifh = @f.read(SIZE_GIFH)
if @gifh[0,3] != "GIF"
raise "不是GIF文件!"
end
if @gifh[3,3] != "87a" and @gifh[3,3] != "89a"
raise "不支持的版本!"
end
end
#--------------------------------------------------------------------------
# ● 读取逻辑屏幕描述块
#--------------------------------------------------------------------------
def read_gifs
@gifs = @f.read(SIZE_GIFS).unpack("S2C3")
# 获取调色板位数
@_pal_bits = (@gifs[2] & 7) + 1
# 是否有全局调色板
if @gifs[2] >> 7 == 1
# 全局调色板大小
@g_pal_size = 3 * (1 << @_pal_bits)
# 读取全局调色板数据
@g_pal = @f.read(@g_pal_size).unpack("C*")
end
end
#--------------------------------------------------------------------------
# ● 读取图象描述块
#--------------------------------------------------------------------------
def read_gifi
@gifi = @f.read(SIZE_GIFI).unpack("S4C")
# 获取宽度和高度
@_width = @gifi[2]
@_height = @gifi[3]
# 清空局部调色板
@l_pal = nil
# 是否有局部调色板
if @gifi[4] >> 7 == 1
# 获取调色板位数
@_pal_bits = (@gifi[4] & 7) + 1
# 局部调色板大小
@l_pal_size = 3 * (1 << @_pal_bits)
# 读取局部调色板数据
@l_pal = @f.read(@l_pal_size).unpack("C*")
end
# 获取交错标记
@_lace = (@gifi[4] >> 6) & 1
# 修正调色板位数
@_pal_bits = @_pal_bits == 1 ? 1 : (@_pal_bits <= 4 ? 4 : 8)
# 获取行字节数
@_width_bytes = (((@_width * @_pal_bits) + 31) >> 5) << 2
# 读取图象压缩数据
self.read_lzw_data
end
#--------------------------------------------------------------------------
# ● 读取图象压缩数据
#--------------------------------------------------------------------------
def read_lzw_data
# 解码用
lzw_mincodelen = @f.read(1)[0]
# 帧数加 1
@gif_count += 1
# 图象块数据
image_data = ""
# 块大小
blocksize = @f.read(1)[0]
while blocksize > 0
image_data += @f.read(blocksize)
blocksize = @f.read(1)[0]
end
# 导出图象
self.dump_imgs(image_data,lzw_mincodelen)
end
#--------------------------------------------------------------------------
# ● 读取扩充块
#--------------------------------------------------------------------------
def read_gife
label = @f.read(1)[0]
case label
when 0xf9 # 图形控制扩展块
@gifc = @f.read(SIZE_GIFC).unpack("C2SC2")
# 获取透明颜色
@_trans_index = nil
if @gifc[1] & 1 > 0
@_trans_index = @gifc[3]
end
when 0x01 # 图形说明扩展块
@gifp = @f.read(SIZE_GIFP).unpack("CS4C4")
blocksize = @f.read(1)[0]
while blocksize > 0
@f.read(blocksize)
blocksize = @f.read(1)[0]
end
when 0xfe # 注解说明扩展块
blocksize = @f.read(1)[0]
while blocksize > 0
@f.read(blocksize)
blocksize = @f.read(1)[0]
end
when 0xff # 应用程序扩展块
@gifa = @f.read(SIZE_GIFA).unpack("C*")
blocksize = @f.read(1)[0]
while blocksize > 0
@f.read(blocksize)
blocksize = @f.read(1)[0]
end
end
end
#--------------------------------------------------------------------------
# ● 设置调色板
#--------------------------------------------------------------------------
def set_pal
@_pal = []
if @l_pal != nil
@_pal = @l_pal
elsif @g_pal != nil
@_pal = @g_pal
else
for i in 0...1 << @_pal_bits
@_pal.push i,i,i
end
end
end
#--------------------------------------------------------------------------
# ● 解码图形数据
#--------------------------------------------------------------------------
def dump_imgs(image_data,lze_len)
@image_data = image_data.unpack("C*")
self.set_pal
@png_data = []
@stack = []
@images = []
@prefix = []
@suffix = []
@bitcount = @_pal_bits
@widthcount = 0
@left_bits = 0x00
@current_bits = lze_len + 0x01
@lzw_clear = 1 << lze_len
@lzw_eoi = @lzw_clear + 1
@nowtablendx = @lzw_clear + 2
@toptablendx = 1 << @current_bits
@wdata = 0
@wcode = 0
@oldcode = 0xffff
@row_num = 0
@tempchar = 0x00
@pass = 0x00
@firstchar = 0
@tempndx = 0
# 读取编码字符
self.read_byte
# 不是@lzw_eoi则循环
while @wcode != @lzw_eoi
# @lzw_clear码
if @wcode == @lzw_clear
for i in 0...@lzw_clear
@prefix[i] = 0xffff
@suffix[i] = i
end
for i in @nowtablendx...4096
@prefix[i] = 0xffff
@suffix[i] = 0x00
end
@current_bits = lze_len + 0x01
@nowtablendx = @lzw_clear + 2
@toptablendx = 1 << @current_bits
@oldcode = 0xffff
# 读取编码字符
self.read_byte
if @wcode != @lzw_eoi
while @prefix[@wcode] != 0xffff
@stack.push(@suffix[@wcode])
@wcode = @prefix[@wcode]
end
@stack.push(@suffix[@wcode])
@firstchar = @stack[-1]
# 输出解码数据
self.output_data
end
else
if @wcode < @nowtablendx
@tempndx = @wcode
else
@tempndx = @oldcode
@stack.push(@firstchar)
end
while @prefix[@tempndx] != 0xffff
@stack.push(@suffix[@tempndx])
@tempndx = @prefix[@tempndx]
end
@stack.push(@suffix[@tempndx])
@firstchar = @stack[-1]
@prefix[@nowtablendx] = @oldcode
@suffix[@nowtablendx] = @firstchar
@nowtablendx += 1
if @nowtablendx == @toptablendx and @current_bits < 12
@current_bits += 1
@toptablendx = 1 << @current_bits
end
# 输出解码数据
self.output_data
end
@oldcode = @wcode
# 读取编码字符
self.read_byte
end
Graphics.update
# 生成png图
self.make_png
end
#--------------------------------------------------------------------------
# ● 读取下一个字节
#--------------------------------------------------------------------------
def read_byte
while @left_bits < @current_bits
@next_char = @image_data.shift
@wdata |= (@next_char << @left_bits)
@left_bits += 0x08
end
@wcode = @wdata & CODE_MASK[@current_bits]
@wdata >>= @current_bits
@left_bits -= @current_bits
end
#--------------------------------------------------------------------------
# ● 输出解码数据
#--------------------------------------------------------------------------
def output_data
while [email protected]?
@tempchar |= (@stack.pop << (8 - @bitcount))
if @bitcount == 8
@images.push(@tempchar)
@tempchar = 0x00
@bitcount = @_pal_bits
else
@bitcount += @_pal_bits
end
@widthcount += 1
if @widthcount == @_width
if @bitcount != @_pal_bits
@images.push(@tempchar)
@tempchar = 0x00
@bitcount = @_pal_bits
end
@png_data[@row_num] = @images.clone
@images.clear
if @_lace > 0
@row_num += INC_TABLE[@pass]
if @row_num >= @_height
@pass += 1
@row_num = BGN_TABLE[@pass]
end
else
@row_num += 1
end
@widthcount = 0
end
end
end
#--------------------------------------------------------------------------
# ● 生成png图片
#--------------------------------------------------------------------------
def make_png
fp = open(@now_path+@filename + sprintf("%02d",@gif_count)+".png","wb")
fp.write(self.make_png_header)
fp.write(self.make_png_ihdr)
fp.write(self.make_png_plte) if @_trans_index.nil?
fp.write(self.make_png_idat)
fp.write(self.make_png_iend)
fp.close
end
#--------------------------------------------------------------------------
# ● png头文件
#--------------------------------------------------------------------------
def make_png_header
return [0x89,0x50,0x4e,0x47,0x0d,0x0a,0x1a,0x0a].pack("C*")
end
#--------------------------------------------------------------------------
# ● png信息头块
#--------------------------------------------------------------------------
def make_png_ihdr
ih_size = [13].pack("N")
ih_sign = "IHDR"
ih_width = [@_width].pack("N")
ih_height = [@_height].pack("N")
if @_trans_index != nil
ih_bit_depth = [@_pal_bits > 8 ? 16 : 8].pack("C")
ih_color_type = [6].pack("C")
else
ih_bit_depth = [@_pal_bits].pack("C")
ih_color_type = [3].pack("C")
end
ih_compression_method = [0].pack("C")
ih_filter_method = [0].pack("C")
ih_interlace_method = [0].pack("C")
string = ih_sign + ih_width + ih_height + ih_bit_depth + ih_color_type +
ih_compression_method + ih_filter_method + ih_interlace_method
ih_crc = [Zlib.crc32(string)].pack("N")
return ih_size + string + ih_crc
end
#--------------------------------------------------------------------------
# ● png调色板块
#--------------------------------------------------------------------------
def make_png_plte
pl_size = [@_pal.size].pack("N")
pl_sign = "PLTE"
pl_data = @_pal.pack("C*")
pl_crc = [Zlib.crc32(pl_sign + pl_data)].pack("N")
return pl_size + pl_sign + pl_data + pl_crc
end
#--------------------------------------------------------------------------
# ● png数据块
#--------------------------------------------------------------------------
def make_png_idat
lz_data = []
if @_trans_index != nil
for i in 0...@png_data.size
lz_data.push 0
for j in @png_data[i]
if j == @_trans_index
lz_data.push @_pal[j*3],@_pal[j*3+1],@_pal[j*3+2],0
else
lz_data.push @_pal[j*3],@_pal[j*3+1],@_pal[j*3+2],255
end
end
end
else
for i in 0...@png_data.size
lz_data.push 0
lz_data += @png_data[i]
end
end
id_data = Zlib::Deflate.deflate(lz_data.pack("C*"),9)
id_size = [id_data.size].pack("N")
id_sign = "IDAT"
id_crc = [Zlib.crc32(id_sign + id_data)].pack("N")
return id_size + id_sign + id_data + id_crc
end
#--------------------------------------------------------------------------
# ● png 结尾块
#--------------------------------------------------------------------------
def make_png_iend
ie_size = [0].pack("N")
ie_sign = "IEND"
ie_crc = [Zlib.crc32(ie_sign)].pack("N")
return ie_size + ie_sign + ie_crc
end
end
GIF.analyze_gif

复制代码

=begin
脚本：【怨念产物】
功能：分解GIF图片为PNG格式。
说明: 直接用 GIF.analyze_gif 使用。
把需要分解的GIF文件放在工程下的GIF文件夹下即可，运行即可，ms速度比较慢。
作者：灼眼的夏娜
=end
=begin
GIF文件格式初步讲解：
1、文件头(6字节)：
2、逻辑屏幕标符(7字节) ：
3、[全局调色板数据] ：根据2中的GlobalFlag确定相关属性，可无。
4、[GIF扩充块]：各种扩充块，可无。
[图形控制扩充块(6字节),图形说明扩充块(13+1+),注释说明扩充块(0+1+),应用程序扩充块(12+1+)]
5、图象描述块：0x2c 开始。
6、[局部调色板]：根据5中的LocalFlag中的LocalPal可以判断有无。
7、图象数据
8、7的第一个字节为LZW编码长度
9、编码长度之后为连续的数据子块，每个数据子块长度为 0 - 256 字节。
10、数据子块的第一个字节为该子块的长度。
11、文件结尾：0x3b
=end
module GIF
# 定义常量
SIZE_GIFH = 6
SIZE_GIFS = 7
SIZE_GIFI = 9
SIZE_GIFC = 6
SIZE_GIFP = 13
SIZE_GIFA = 12
CODE_MASK = [0x0000,
0x0001,0x0003,0x0007,0x000f,
0x001f,0x003f,0x007f,0x00ff,
0x01ff,0x03ff,0x07ff,0x0fff]
INC_TABLE = [8,8,4,2,0]
BGN_TABLE = [0,4,2,1,0]
# 建立文件夹
Dir.mkdir("GIF") unless Dir["*"].include?("GIF")
# 函数定义
module_function
#--------------------------------------------------------------------------
# ● 分解gif图片
#--------------------------------------------------------------------------
def analyze_gif
@old_dir = Dir.pwd
Dir.chdir("GIF")
@total_gif = []
for g in Dir["*"]
suf = g.split(/\./)
if suf[1].is_a?(String) and suf[1].downcase == "gif"
@total_gif.push(g)
Dir.mkdir(suf[0]) unless Dir["*"].include? suf[0]
end
end
@total_gif.each{|file| self.readdata(file)}
Dir.chdir(@old_dir)
p '全部分解完毕，点击确定退出'
exit
end
#--------------------------------------------------------------------------
# ● 读取文件数据
#--------------------------------------------------------------------------
def readdata(filename)
# 初始化数据
self.initial_var(filename)
# 打开文件
begin
@f = open(filename,"rb")
# 读取文件头
self.read_gifh
# 读取逻辑屏幕描述块
self.read_gifs
# 读取下一个字节
@temp = @f.read(1)[0]
# 循环读取每个图象描述块
while true
if @temp == 0x2c
# 读取图象描述块
self.read_gifi
end
if @temp == 0x21
# 读取图象扩展块
self.read_gife
end
if @temp == 0x3b
break
end
# 读取下一个字节
@temp = @f.read(1)[0]
end
# end
p @filename + '分解完毕...'
ensure
@f.close
end
end
#--------------------------------------------------------------------------
# ● 初始化变量
#--------------------------------------------------------------------------
def initial_var(filename)
@gif_count = 0
@f = nil
@temp = nil
@filename = filename.split(/\./)[0]
@now_path = @filename + "/"
end
#--------------------------------------------------------------------------
# ● 读取文件头
#--------------------------------------------------------------------------
def read_gifh
@gifh = @f.read(SIZE_GIFH)
if @gifh[0,3] != "GIF"
raise "不是GIF文件!"
end
if @gifh[3,3] != "87a" and @gifh[3,3] != "89a"
raise "不支持的版本!"
end
end
#--------------------------------------------------------------------------
# ● 读取逻辑屏幕描述块
#--------------------------------------------------------------------------
def read_gifs
@gifs = @f.read(SIZE_GIFS).unpack("S2C3")
# 获取调色板位数
@_pal_bits = (@gifs[2] & 7) + 1
# 是否有全局调色板
if @gifs[2] >> 7 == 1
# 全局调色板大小
@g_pal_size = 3 * (1 << @_pal_bits)
# 读取全局调色板数据
@g_pal = @f.read(@g_pal_size).unpack("C*")
end
end
#--------------------------------------------------------------------------
# ● 读取图象描述块
#--------------------------------------------------------------------------
def read_gifi
@gifi = @f.read(SIZE_GIFI).unpack("S4C")
# 获取宽度和高度
@_width = @gifi[2]
@_height = @gifi[3]
# 清空局部调色板
@l_pal = nil
# 是否有局部调色板
if @gifi[4] >> 7 == 1
# 获取调色板位数
@_pal_bits = (@gifi[4] & 7) + 1
# 局部调色板大小
@l_pal_size = 3 * (1 << @_pal_bits)
# 读取局部调色板数据
@l_pal = @f.read(@l_pal_size).unpack("C*")
end
# 获取交错标记
@_lace = (@gifi[4] >> 6) & 1
# 修正调色板位数
@_pal_bits = @_pal_bits == 1 ? 1 : (@_pal_bits <= 4 ? 4 : 8)
# 获取行字节数
@_width_bytes = (((@_width * @_pal_bits) + 31) >> 5) << 2
# 读取图象压缩数据
self.read_lzw_data
end
#--------------------------------------------------------------------------
# ● 读取图象压缩数据
#--------------------------------------------------------------------------
def read_lzw_data
# 解码用
lzw_mincodelen = @f.read(1)[0]
# 帧数加 1
@gif_count += 1
# 图象块数据
image_data = ""
# 块大小
blocksize = @f.read(1)[0]
while blocksize > 0
image_data += @f.read(blocksize)
blocksize = @f.read(1)[0]
end
# 导出图象
self.dump_imgs(image_data,lzw_mincodelen)
end
#--------------------------------------------------------------------------
# ● 读取扩充块
#--------------------------------------------------------------------------
def read_gife
label = @f.read(1)[0]
case label
when 0xf9 # 图形控制扩展块
@gifc = @f.read(SIZE_GIFC).unpack("C2SC2")
# 获取透明颜色
@_trans_index = nil
if @gifc[1] & 1 > 0
@_trans_index = @gifc[3]
end
when 0x01 # 图形说明扩展块
@gifp = @f.read(SIZE_GIFP).unpack("CS4C4")
blocksize = @f.read(1)[0]
while blocksize > 0
@f.read(blocksize)
blocksize = @f.read(1)[0]
end
when 0xfe # 注解说明扩展块
blocksize = @f.read(1)[0]
while blocksize > 0
@f.read(blocksize)
blocksize = @f.read(1)[0]
end
when 0xff # 应用程序扩展块
@gifa = @f.read(SIZE_GIFA).unpack("C*")
blocksize = @f.read(1)[0]
while blocksize > 0
@f.read(blocksize)
blocksize = @f.read(1)[0]
end
end
end
#--------------------------------------------------------------------------
# ● 设置调色板
#--------------------------------------------------------------------------
def set_pal
@_pal = []
if @l_pal != nil
@_pal = @l_pal
elsif @g_pal != nil
@_pal = @g_pal
else
for i in 0...1 << @_pal_bits
@_pal.push i,i,i
end
end
end
#--------------------------------------------------------------------------
# ● 解码图形数据
#--------------------------------------------------------------------------
def dump_imgs(image_data,lze_len)
@image_data = image_data.unpack("C*")
self.set_pal
@png_data = []
@stack = []
@images = []
@prefix = []
@suffix = []
@bitcount = @_pal_bits
@widthcount = 0
@left_bits = 0x00
@current_bits = lze_len + 0x01
@lzw_clear = 1 << lze_len
@lzw_eoi = @lzw_clear + 1
@nowtablendx = @lzw_clear + 2
@toptablendx = 1 << @current_bits
@wdata = 0
@wcode = 0
@oldcode = 0xffff
@row_num = 0
@tempchar = 0x00
@pass = 0x00
@firstchar = 0
@tempndx = 0
# 读取编码字符
self.read_byte
# 不是@lzw_eoi则循环
while @wcode != @lzw_eoi
# @lzw_clear码
if @wcode == @lzw_clear
for i in 0...@lzw_clear
@prefix[i] = 0xffff
@suffix[i] = i
end
for i in @nowtablendx...4096
@prefix[i] = 0xffff
@suffix[i] = 0x00
end
@current_bits = lze_len + 0x01
@nowtablendx = @lzw_clear + 2
@toptablendx = 1 << @current_bits
@oldcode = 0xffff
# 读取编码字符
self.read_byte
if @wcode != @lzw_eoi
while @prefix[@wcode] != 0xffff
@stack.push(@suffix[@wcode])
@wcode = @prefix[@wcode]
end
@stack.push(@suffix[@wcode])
@firstchar = @stack[-1]
# 输出解码数据
self.output_data
end
else
if @wcode < @nowtablendx
@tempndx = @wcode
else
@tempndx = @oldcode
@stack.push(@firstchar)
end
while @prefix[@tempndx] != 0xffff
@stack.push(@suffix[@tempndx])
@tempndx = @prefix[@tempndx]
end
@stack.push(@suffix[@tempndx])
@firstchar = @stack[-1]
@prefix[@nowtablendx] = @oldcode
@suffix[@nowtablendx] = @firstchar
@nowtablendx += 1
if @nowtablendx == @toptablendx and @current_bits < 12
@current_bits += 1
@toptablendx = 1 << @current_bits
end
# 输出解码数据
self.output_data
end
@oldcode = @wcode
# 读取编码字符
self.read_byte
end
Graphics.update
# 生成png图
self.make_png
end
#--------------------------------------------------------------------------
# ● 读取下一个字节
#--------------------------------------------------------------------------
def read_byte
while @left_bits < @current_bits
@next_char = @image_data.shift
@wdata |= (@next_char << @left_bits)
@left_bits += 0x08
end
@wcode = @wdata & CODE_MASK[@current_bits]
@wdata >>= @current_bits
@left_bits -= @current_bits
end
#--------------------------------------------------------------------------
# ● 输出解码数据
#--------------------------------------------------------------------------
def output_data
while [email protected]?
@tempchar |= (@stack.pop << (8 - @bitcount))
if @bitcount == 8
@images.push(@tempchar)
@tempchar = 0x00
@bitcount = @_pal_bits
else
@bitcount += @_pal_bits
end
@widthcount += 1
if @widthcount == @_width
if @bitcount != @_pal_bits
@images.push(@tempchar)
@tempchar = 0x00
@bitcount = @_pal_bits
end
@png_data[@row_num] = @images.clone
@images.clear
if @_lace > 0
@row_num += INC_TABLE[@pass]
if @row_num >= @_height
@pass += 1
@row_num = BGN_TABLE[@pass]
end
else
@row_num += 1
end
@widthcount = 0
end
end
end
#--------------------------------------------------------------------------
# ● 生成png图片
#--------------------------------------------------------------------------
def make_png
fp = open(@now_path+@filename + sprintf("%02d",@gif_count)+".png","wb")
fp.write(self.make_png_header)
fp.write(self.make_png_ihdr)
fp.write(self.make_png_plte) if @_trans_index.nil?
fp.write(self.make_png_idat)
fp.write(self.make_png_iend)
fp.close
end
#--------------------------------------------------------------------------
# ● png头文件
#--------------------------------------------------------------------------
def make_png_header
return [0x89,0x50,0x4e,0x47,0x0d,0x0a,0x1a,0x0a].pack("C*")
end
#--------------------------------------------------------------------------
# ● png信息头块
#--------------------------------------------------------------------------
def make_png_ihdr
ih_size = [13].pack("N")
ih_sign = "IHDR"
ih_width = [@_width].pack("N")
ih_height = [@_height].pack("N")
if @_trans_index != nil
ih_bit_depth = [@_pal_bits > 8 ? 16 : 8].pack("C")
ih_color_type = [6].pack("C")
else
ih_bit_depth = [@_pal_bits].pack("C")
ih_color_type = [3].pack("C")
end
ih_compression_method = [0].pack("C")
ih_filter_method = [0].pack("C")
ih_interlace_method = [0].pack("C")
string = ih_sign + ih_width + ih_height + ih_bit_depth + ih_color_type +
ih_compression_method + ih_filter_method + ih_interlace_method
ih_crc = [Zlib.crc32(string)].pack("N")
return ih_size + string + ih_crc
end
#--------------------------------------------------------------------------
# ● png调色板块
#--------------------------------------------------------------------------
def make_png_plte
pl_size = [@_pal.size].pack("N")
pl_sign = "PLTE"
pl_data = @_pal.pack("C*")
pl_crc = [Zlib.crc32(pl_sign + pl_data)].pack("N")
return pl_size + pl_sign + pl_data + pl_crc
end
#--------------------------------------------------------------------------
# ● png数据块
#--------------------------------------------------------------------------
def make_png_idat
lz_data = []
if @_trans_index != nil
for i in 0...@png_data.size
lz_data.push 0
for j in @png_data[i]
if j == @_trans_index
lz_data.push @_pal[j*3],@_pal[j*3+1],@_pal[j*3+2],0
else
lz_data.push @_pal[j*3],@_pal[j*3+1],@_pal[j*3+2],255
end
end
end
else
for i in 0...@png_data.size
lz_data.push 0
lz_data += @png_data[i]
end
end
id_data = Zlib::Deflate.deflate(lz_data.pack("C*"),9)
id_size = [id_data.size].pack("N")
id_sign = "IDAT"
id_crc = [Zlib.crc32(id_sign + id_data)].pack("N")
return id_size + id_sign + id_data + id_crc
end
#--------------------------------------------------------------------------
# ● png 结尾块
#--------------------------------------------------------------------------
def make_png_iend
ie_size = [0].pack("N")
ie_sign = "IEND"
ie_crc = [Zlib.crc32(ie_sign)].pack("N")
return ie_size + ie_sign + ie_crc
end
end
GIF.analyze_gif

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