纯Javascript的PNG图形验证码生成组件(ASP Sample)

组件Identify.sct

<?xml version="1.0" encoding="utf-8"?>

<?component error="true" debug="true"?>

<![CDATA[

纯Javascript生成的png图片组件

]]>

</comment>

</method>

</method>

</public>

<![CDATA[

var ASCII=new Array(36);

ASCII[0] = "1110000111110111101111011110111101111011110111101111011110111101111011110111101111011110111110000111";

ASCII[1] = "1111011111110001111111110111111111011111111101111111110111111111011111111101111111110111111100000111";

ASCII[2] = "1110000111110111101111011110111111111011111111011111111011111111011111111011111111011110111100000011";

ASCII[3] = "1110000111110111101111011110111111110111111100111111111101111111111011110111101111011110111110000111";

ASCII[4] = "1111101111111110111111110011111110101111110110111111011011111100000011111110111111111011111111000011";

ASCII[5] = "1100000011110111111111011111111101000111110011101111111110111111111011110111101111011110111110000111";

ASCII[6] = "1111000111111011101111011111111101111111110100011111001110111101111011110111101111011110111110000111";

ASCII[7] = "1100000011110111011111011101111111101111111110111111110111111111011111111101111111110111111111011111";

ASCII[8] = "1110000111110111101111011110111101111011111000011111101101111101111011110111101111011110111110000111";

ASCII[9] = "1110001111110111011111011110111101111011110111001111100010111111111011111111101111011101111110001111";

ASCII[10] = "1111011111111101111111101011111110101111111010111111101011111100000111110111011111011101111000100011";

ASCII[11] = "1000000111110111101111011110111101110111110000111111011101111101111011110111101111011110111000000111";

ASCII[12] = "1110000011110111101110111110111011111111101111111110111111111011111111101111101111011101111110001111";

ASCII[13] = "0000001111110111011111011110111101111011110111101111011110111101111011110111101111011101110000001111";

ASCII[14] = "1000000111110111101111011011111101101111110000111111011011111101101111110111111111011110111000000111";

ASCII[15] = "1000000111110111101111011011111101101111110000111111011011111101101111110111111111011111111000111111";

ASCII[16] = "0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000";

var FONT_WIDTH=10;

var FONT_HEIGHT=10;

var WIDTH=160;

var HEIGHT=40;

var DEPTH=8;

var MAP=new Array((WIDTH+1)*HEIGHT);

function B4(b){

return String.fromCharCode((b>>24)&0xFF, (b>>16)&0xFF, (b>>8)&0xFF, b&0xFF);

}

function B2(b){

return String.fromCharCode((b>>8)&0xFF, b&0xFF);

}

function B1(b){

return String.fromCharCode(b&0xFF);

}

var CRC_TABLE=new Array(256);

// Make crc table

function CRC32_Init(){

var n=0, k=0;

var c;

for(n=0; n<256; n++){

c=n;

for(k=0; k<8; k++){

if (c&1)

c=0xedb88320^(c>>>1);

else

c=c>>>1;

}

CRC_TABLE[n]=c;

}

CRC32_Init();

function CRC32(str){

var c=0xFFFFFFFF;

var n=0;

for(n=0; n<str.length; n++){

c=CRC_TABLE[(c^str.charCodeAt(n))&0xFF]^(c>>>8);

}

return c^0xFFFFFFFF;

}

function png_signature(){

return [0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a];

}

function png_chunk(type, str){

var ary=[], i=0;

var crc;

crc=CRC32(type+str);

str=B4(str.length)+type+str;

str=str+B4(crc);

for(i=0; i<str.length; i++)

ary.push(str.charCodeAt(i));

return ary;

}

function png_IHDR(){

return png_chunk("IHDR", B4(WIDTH)+B4(HEIGHT)+B1(DEPTH)+B1(3)+B1(0)+B1(0)+B1(0));

}

function png_PLTE(){

return png_chunk("PLTE",

B1(255)+B1(255)+B1(255) //0

+B1(224)+B1(224)+B1(224) //1

+B1(192)+B1(192)+B1(192) //2

+B1(160)+B1(160)+B1(160) //3

+B1(128)+B1(128)+B1(128) //4

+B1(96)+B1(96)+B1(96) //5

+B1(64)+B1(64)+B1(64) //6

+B1(32)+B1(32)+B1(32) //7

+B1(0)+B1(0)+B1(0) //8

);

}

function png_IDAT(){

var h=HEIGHT

var strip=WIDTH+1;

var x, y;

var data=""

for(y=0; y<h; y++) for(x=0; x<strip; x++)

data=data+String.fromCharCode(MAP[x+y*strip]);

var LEN=data.length;

var NLEN=LEN^0xFFFFFFFF;

// Calculate Simple Adler-32 checksum

var BASE=65521, NMAX=5552;

var s1=1, s2=0, n=NMAX;

var i;

for(i=0; i<LEN; i++){

s1+=data.charCodeAt(i);

s2+=s1;

if((n--)==0){

s1%=BASE;

s2%=BASE;

n=NMAX;

}

s1%=BASE;

s2%=BASE;

return png_chunk("IDAT", B1(0x78)+B1(0xDA)+B1(0x01)+ /*uncompressd lz77*/

String.fromCharCode((LEN)&0xFF, (LEN>>8)&0xFF, (NLEN)&0xFF, (NLEN>>8)&0xFF) +

data+B4((s2<<16)|s1));

}

function png_IEND(){

return png_chunk("IEND", "");

}

function png_output(){

var png=dat=[], i=0

var str="";

dat=dat.concat(png_signature(), png_IHDR(), png_PLTE(), png_IDAT(), png_IEND());

if(dat.length % 2==1) dat.push(0); // Fill data to make it 2-byte aligned

for(i=0; i<dat.length-1; i+=2){

png.push(String.fromCharCode( dat[i] + (dat[i+1]<<8) ));

}

return png.join("");

}

function Map_Init(){

var x, y;

var strip=WIDTH+1;

for(x=0; x<strip; x++) for(y=0; y<HEIGHT; y++){

if(x==0)

MAP[x+y*strip]=0; // scanline indicator

else

MAP[x+y*strip]=8; // bgcolor

}

function putPixel(x, y, c){

MAP[x+1+y*(WIDTH+1)]=c;

}

function getPixel(x, y, c){

return MAP[x+1+y*(WIDTH+1)];

}

function putChar(ox, oy, ch){

var x, y;

oy+=Math.floor(Math.random()*5-5.5);

for(y=0;y<FONT_HEIGHT;y++){

ox+=Math.floor(Math.random()*2+0.5)-1;

for(x=0;x<FONT_WIDTH;x++){

var c=1-parseInt(ASCII[ch].charAt(x+y*FONT_WIDTH));

if(c>0){

c=0;

// double size, bold and random italic

putPixel(ox+x*3, oy+y*2, c);

putPixel(ox+x*3+1, oy+y*2, c);

putPixel(ox+x*3+2, oy+y*2, c);

putPixel(ox+x*3, oy+y*2+1, c);

putPixel(ox+x*3+1, oy+y*2+1, c);

putPixel(ox+x*3+2, oy+y*2+1, c);

}

function putNoise(n, c){

var i, x, y;

for(i=0; i<n; i++){

x=Math.floor(Math.random()*WIDTH);

y=Math.floor(Math.random()*HEIGHT);

putPixel(x, y, c);

}

function smooth(){

var x, y;

var c0, c1, c2, c3, c4; // center, up, right, down, left

for(x=0; x<WIDTH; x++) for(y=0; y<HEIGHT; y++){

c0=getPixel(x, y);

c1=(y>0)?getPixel(x, y-1):c0;

c2=(x<WIDTH)?getPixel(x+1, y):c0;

c3=(y<HEIGHT)?getPixel(x, y+1):c0;

c4=(x>0)?getPixel(x-1, y):c0;

putPixel(x, y, Math.floor((c0*6+c1+c2+c3+c4)/10+0.5));

}

// MD5

function captcha(str){

Map_Init();

var ox=FONT_WIDTH/2, oy=(HEIGHT-FONT_HEIGHT)/2;

var i;

var idx=0;

var c;

for(i=0; i<str.length; i++){

c=str.charCodeAt(i);

if(c<=57 && c>=48)

idx=c-48;

else if(c<=70 && c>=65)

idx=c-65+10;

else idx=16;

putChar(ox+i*FONT_WIDTH*2.5, oy, idx);

}

putNoise(500, 4);

putNoise(500, 2);

smooth();

return png_output();

}]]>

</script>

</scriptlet>

</package>

调用页面Identify.asp

Randomize

Response.CacheControl="no-cache"

Response.ContentType="image/png"

'Set Identify = GetObject("script:"&Server.MapPath("Identify.sct#Identify"))

Set Identify = Server.CreateObject("Javascript.PngIdentify")

rndStr=Left(Identify.MD5(cstr(rnd)),6)

Response.BinaryWrite Identify.MakePng(rndStr)

Set Identify=Nothing

posted @ 2006-06-21 14:38 Rookie.Zhang 阅读(1927) 评论(1) 收藏举报

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纯Javascript的PNG图形验证码生成组件(ASP Sample)

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爱睇资讯

IT资讯，最新最前沿。我们的口号：能解决实际问题的软件才是好软件！业界新闻均来自 華爾街日報 中文網

纯Javascript的PNG图形验证码生成组件(ASP Sample)

公告

IT资讯，最新最前沿。我们的口号：能解决实际问题的软件才是好软件！业界新闻均来自華爾街日報中文網