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微信小程序 | 人脸识别的最终解决方案

时间:2024-04-04 12:30:43 来源:网络cs 作者:康由 栏目:培训机构 阅读:

标签: 解决  方案  识别  程序 

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一、人脸识别功能现状

1.1 微信原生接口篇

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微信原生的人脸识别接口可以完美的结合小程序所采集到的图像,可以达到实时帧级别的识别,是高效开发人脸识别功能的首选!

但是,由于人脸数据是个人的敏感数据,微信在开放该接口出来时,就是为了方便各行各业的业务开展。所以,我们要用它,就必须具备相应的资质。后续才能通过审核并发布上线。

资质说明链接:微信开放能力文档
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1.2 百度接口篇

百度人脸识别SDK的服务模式是用户在平台开通好相应的权限以及获取到appId等一系列操作之后,再到我们开发端是采用对百度人脸验证平台的相应接口进行发送验证请求才能实现服务的调用。

也就是说:百度已经人脸验证服务帮你全部搭建好了,你只需要发起请求进行调即可。

百度人脸识别服务地址
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可以按量收费,目前根据你的业务量的QPS进行计费统计。

如果您的业务并发支持要求较高,免费测试 QPS 不能满足,您可以随时购买扩充 QPS ,QPS 可包月购买,也可按天购买,灵活多样,适应多场景需求。


1.3 虹软接口篇

在这里插入图片描述

平台链接地址:虹软接口平台

虹软 和 百度 这两者之间的区别在于:

百度直接替你部署好了识别用的服务,你只需要按照文档指引向其特定的 接口发送数据即可获得你的结果,在某些主前端开发轻后端服务的应用来说还是很有优势的。虹软所走的模式是不管你是离线还是在线都能让你运行,他把搭建服务端的工作留给你自己去做。在这样的模式下,你可以实时把控用户的人脸数据,对其进行自定义操作,从而构造更为灵活的人脸设别方式,对业务场景的开发也可以有更多操作的空间!

二、人脸识别功能流程

在这里插入图片描述


三、微信接口解析

3.1 微信摄像头组件的使用

小程序中要使用到摄像头的功能在于使用<camera>标签:
<camera v-if='isAuthCamera' device-position="front" class="camera" flash="off" resolution='high' />

对于<camera>标签核心的参数如下:

属性类型必填说明可选值默认值
modestring应用模式,只在初始化时有效,不能动态变更normal: 相机模式 】【scanCode:扫码模式normal
属性类型必填说明可选值默认值
resolutionstring分辨率,不支持动态修改low 低 】【medium 中】【high 高medium
属性类型必填说明可选值默认值
device-positionstring摄像头朝向front 前置 】【back 后置back
属性类型必填说明可选值默认值
flashstring闪光灯,值为 auto , on, offauto 自动 】【on 打开】【off 关闭】【torch 常亮auto

3.2 微信小程序实时视频帧获取

对如何调用和开启微信小程序中的摄像头摄像和拍照功能进行学习:微信小程序–摄像头接口详解

首先需要调用CameraContext wx.createCameraContext()方法创建camera操作对象。然后在camera对象之后调用onCameraFrame(function callback),该方法用于实时获取摄像头所捕捉的相片帧,从而用于与后端人脸识别引擎进行交互。
const context = wx.createCameraContext()const listener = context.onCameraFrame((frame) => {  console.log(frame.data instanceof ArrayBuffer, frame.width, frame.height)})listener.start()

四、工具包的准备

4.1 将帧数据转为Base64

针对onCameraFrame()方法,获取到的是相机所捕捉的图片帧数据,这个时候我们需要将其转为Base64格式的图片数据,这是为了让其传输到后端能够被人脸识别引擎所使用!在微信所开放的用于将帧数据转化为base 64接口中wx.arrayBufferToBase64(已弃用),项目中需要用摄像头获取人脸并将获取的ArrayBuffer数据转化为base64,就需要经过一下流程:
在这里插入图片描述
代码如下:
let pngData = ToPNG.encode([frame.data], frame.width, frame.height),  base64 = Base64Util.arrayBufferToBase64(pngData)
所以先准备ArrayBuffer数据转化为PNG数据的工具包ToPNG.js
import pako from 'pako'var UPNG = {};UPNG.toRGBA8 = function (out) {    var w = out.width,        h = out.height;    if (out.tabs.acTL == null) return [UPNG.toRGBA8.decodeImage(out.data, w, h, out).buffer];    var frms = [];    if (out.frames[0].data == null) out.frames[0].data = out.data;    var len = w * h * 4,        img = new Uint8Array(len),        empty = new Uint8Array(len),        prev = new Uint8Array(len);    for (var i = 0; i < out.frames.length; i++) {        var frm = out.frames[i];        var fx = frm.rect.x,            fy = frm.rect.y,            fw = frm.rect.width,            fh = frm.rect.height;        var fdata = UPNG.toRGBA8.decodeImage(frm.data, fw, fh, out);        if (i != 0)            for (var j = 0; j < len; j++) prev[j] = img[j];        if (frm.blend == 0) UPNG._copyTile(fdata, fw, fh, img, w, h, fx, fy, 0);        else if (frm.blend == 1) UPNG._copyTile(fdata, fw, fh, img, w, h, fx, fy, 1);        frms.push(img.buffer.slice(0));        if (frm.dispose == 0) {} else if (frm.dispose == 1) UPNG._copyTile(empty, fw, fh, img, w, h, fx, fy, 0);        else if (frm.dispose == 2)            for (var j = 0; j < len; j++) img[j] = prev[j];    }    return frms;}UPNG.toRGBA8.decodeImage = function (data, w, h, out) {    var area = w * h,        bpp = UPNG.decode._getBPP(out);    var bpl = Math.ceil(w * bpp / 8); // bytes per line    var bf = new Uint8Array(area * 4),        bf32 = new Uint32Array(bf.buffer);    var ctype = out.ctype,        depth = out.depth;    var rs = UPNG._bin.readUshort;    //console.log(ctype, depth);    var time = Date.now();    if (ctype == 6) { // RGB + alpha        var qarea = area << 2;        if (depth == 8)            for (var i = 0; i < qarea; i += 4) {                bf[i] = data[i];                bf[i + 1] = data[i + 1];                bf[i + 2] = data[i + 2];                bf[i + 3] = data[i + 3];            }        if (depth == 16)            for (var i = 0; i < qarea; i++) {                bf[i] = data[i << 1];            }    } else if (ctype == 2) { // RGB        var ts = out.tabs["tRNS"];        if (ts == null) {            if (depth == 8)                for (var i = 0; i < area; i++) {                    var ti = i * 3;                    bf32[i] = (255 << 24) | (data[ti + 2] << 16) | (data[ti + 1] << 8) | data[ti];                }            if (depth == 16)                for (var i = 0; i < area; i++) {                    var ti = i * 6;                    bf32[i] = (255 << 24) | (data[ti + 4] << 16) | (data[ti + 2] << 8) | data[ti];                }        } else {            var tr = ts[0],                tg = ts[1],                tb = ts[2];            if (depth == 8)                for (var i = 0; i < area; i++) {                    var qi = i << 2,                        ti = i * 3;                    bf32[i] = (255 << 24) | (data[ti + 2] << 16) | (data[ti + 1] << 8) | data[ti];                    if (data[ti] == tr && data[ti + 1] == tg && data[ti + 2] == tb) bf[qi + 3] = 0;                }            if (depth == 16)                for (var i = 0; i < area; i++) {                    var qi = i << 2,                        ti = i * 6;                    bf32[i] = (255 << 24) | (data[ti + 4] << 16) | (data[ti + 2] << 8) | data[ti];                    if (rs(data, ti) == tr && rs(data, ti + 2) == tg && rs(data, ti + 4) == tb) bf[qi + 3] = 0;                }        }    } else if (ctype == 3) { // palette        var p = out.tabs["PLTE"],            ap = out.tabs["tRNS"],            tl = ap ? ap.length : 0;        //console.log(p, ap);        if (depth == 1)            for (var y = 0; y < h; y++) {                var s0 = y * bpl,                    t0 = y * w;                for (var i = 0; i < w; i++) {                    var qi = (t0 + i) << 2,                        j = ((data[s0 + (i >> 3)] >> (7 - ((i & 7) << 0))) & 1),                        cj = 3 * j;                    bf[qi] = p[cj];                    bf[qi + 1] = p[cj + 1];                    bf[qi + 2] = p[cj + 2];                    bf[qi + 3] = (j < tl) ? ap[j] : 255;                }            }        if (depth == 2)            for (var y = 0; y < h; y++) {                var s0 = y * bpl,                    t0 = y * w;                for (var i = 0; i < w; i++) {                    var qi = (t0 + i) << 2,                        j = ((data[s0 + (i >> 2)] >> (6 - ((i & 3) << 1))) & 3),                        cj = 3 * j;                    bf[qi] = p[cj];                    bf[qi + 1] = p[cj + 1];                    bf[qi + 2] = p[cj + 2];                    bf[qi + 3] = (j < tl) ? ap[j] : 255;                }            }        if (depth == 4)            for (var y = 0; y < h; y++) {                var s0 = y * bpl,                    t0 = y * w;                for (var i = 0; i < w; i++) {                    var qi = (t0 + i) << 2,                        j = ((data[s0 + (i >> 1)] >> (4 - ((i & 1) << 2))) & 15),                        cj = 3 * j;                    bf[qi] = p[cj];                    bf[qi + 1] = p[cj + 1];                    bf[qi + 2] = p[cj + 2];                    bf[qi + 3] = (j < tl) ? ap[j] : 255;                }            }        if (depth == 8)            for (var i = 0; i < area; i++) {                var qi = i << 2,                    j = data[i],                    cj = 3 * j;                bf[qi] = p[cj];                bf[qi + 1] = p[cj + 1];                bf[qi + 2] = p[cj + 2];                bf[qi + 3] = (j < tl) ? ap[j] : 255;            }    } else if (ctype == 4) { // gray + alpha        if (depth == 8)            for (var i = 0; i < area; i++) {                var qi = i << 2,                    di = i << 1,                    gr = data[di];                bf[qi] = gr;                bf[qi + 1] = gr;                bf[qi + 2] = gr;                bf[qi + 3] = data[di + 1];            }        if (depth == 16)            for (var i = 0; i < area; i++) {                var qi = i << 2,                    di = i << 2,                    gr = data[di];                bf[qi] = gr;                bf[qi + 1] = gr;                bf[qi + 2] = gr;                bf[qi + 3] = data[di + 2];            }    } else if (ctype == 0) { // gray        var tr = out.tabs["tRNS"] ? out.tabs["tRNS"] : -1;        for (var y = 0; y < h; y++) {            var off = y * bpl,                to = y * w;            if (depth == 1)                for (var x = 0; x < w; x++) {                    var gr = 255 * ((data[off + (x >>> 3)] >>> (7 - ((x & 7)))) & 1),                        al = (gr == tr * 255) ? 0 : 255;                    bf32[to + x] = (al << 24) | (gr << 16) | (gr << 8) | gr;                }            else if (depth == 2)                for (var x = 0; x < w; x++) {                    var gr = 85 * ((data[off + (x >>> 2)] >>> (6 - ((x & 3) << 1))) & 3),                        al = (gr == tr * 85) ? 0 : 255;                    bf32[to + x] = (al << 24) | (gr << 16) | (gr << 8) | gr;                }            else if (depth == 4)                for (var x = 0; x < w; x++) {                    var gr = 17 * ((data[off + (x >>> 1)] >>> (4 - ((x & 1) << 2))) & 15),                        al = (gr == tr * 17) ? 0 : 255;                    bf32[to + x] = (al << 24) | (gr << 16) | (gr << 8) | gr;                }            else if (depth == 8)                for (var x = 0; x < w; x++) {                    var gr = data[off + x],                        al = (gr == tr) ? 0 : 255;                    bf32[to + x] = (al << 24) | (gr << 16) | (gr << 8) | gr;                }            else if (depth == 16)                for (var x = 0; x < w; x++) {                    var gr = data[off + (x << 1)],                        al = (rs(data, off + (x << 1)) == tr) ? 0 : 255;                    bf32[to + x] = (al << 24) | (gr << 16) | (gr << 8) | gr;                }        }    }    //console.log(Date.now()-time);    return bf;}UPNG.decode = function (buff) {    var data = new Uint8Array(buff),        offset = 8,        bin = UPNG._bin,        rUs = bin.readUshort,        rUi = bin.readUint;    var out = {        tabs: {},        frames: []    };    var dd = new Uint8Array(data.length),        doff = 0; // put all IDAT data into it    var fd, foff = 0; // frames    var mgck = [0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a];    for (var i = 0; i < 8; i++)        if (data[i] != mgck[i]) throw "The input is not a PNG file!";    while (offset < data.length) {        var len = bin.readUint(data, offset);        offset += 4;        var type = bin.readASCII(data, offset, 4);        offset += 4;        //console.log(type,len);        if (type == "IHDR") {            UPNG.decode._IHDR(data, offset, out);        } else if (type == "CgBI") {            out.tabs[type] = data.slice(offset, offset + 4);        } else if (type == "IDAT") {            for (var i = 0; i < len; i++) dd[doff + i] = data[offset + i];            doff += len;        } else if (type == "acTL") {            out.tabs[type] = {                num_frames: rUi(data, offset),                num_plays: rUi(data, offset + 4)            };            fd = new Uint8Array(data.length);        } else if (type == "fcTL") {            if (foff != 0) {                var fr = out.frames[out.frames.length - 1];                fr.data = UPNG.decode._decompress(out, fd.slice(0, foff), fr.rect.width, fr.rect.height);                foff = 0;            }            var rct = {                x: rUi(data, offset + 12),                y: rUi(data, offset + 16),                width: rUi(data, offset + 4),                height: rUi(data, offset + 8)            };            var del = rUs(data, offset + 22);            del = rUs(data, offset + 20) / (del == 0 ? 100 : del);            var frm = {                rect: rct,                delay: Math.round(del * 1000),                dispose: data[offset + 24],                blend: data[offset + 25]            };            //console.log(frm);            out.frames.push(frm);        } else if (type == "fdAT") {            for (var i = 0; i < len - 4; i++) fd[foff + i] = data[offset + i + 4];            foff += len - 4;        } else if (type == "pHYs") {            out.tabs[type] = [bin.readUint(data, offset), bin.readUint(data, offset + 4), data[offset + 8]];        } else if (type == "cHRM") {            out.tabs[type] = [];            for (var i = 0; i < 8; i++) out.tabs[type].push(bin.readUint(data, offset + i * 4));        } else if (type == "tEXt" || type == "zTXt") {            if (out.tabs[type] == null) out.tabs[type] = {};            var nz = bin.nextZero(data, offset);            var keyw = bin.readASCII(data, offset, nz - offset);            var text, tl = offset + len - nz - 1;            if (type == "tEXt") text = bin.readASCII(data, nz + 1, tl);            else {                var bfr = UPNG.decode._inflate(data.slice(nz + 2, nz + 2 + tl));                text = bin.readUTF8(bfr, 0, bfr.length);            }            out.tabs[type][keyw] = text;        } else if (type == "iTXt") {            if (out.tabs[type] == null) out.tabs[type] = {};            var nz = 0,                off = offset;            nz = bin.nextZero(data, off);            var keyw = bin.readASCII(data, off, nz - off);            off = nz + 1;            var cflag = data[off],                cmeth = data[off + 1];            off += 2;            nz = bin.nextZero(data, off);            var ltag = bin.readASCII(data, off, nz - off);            off = nz + 1;            nz = bin.nextZero(data, off);            var tkeyw = bin.readUTF8(data, off, nz - off);            off = nz + 1;            var text, tl = len - (off - offset);            if (cflag == 0) text = bin.readUTF8(data, off, tl);            else {                var bfr = UPNG.decode._inflate(data.slice(off, off + tl));                text = bin.readUTF8(bfr, 0, bfr.length);            }            out.tabs[type][keyw] = text;        } else if (type == "PLTE") {            out.tabs[type] = bin.readBytes(data, offset, len);        } else if (type == "hIST") {            var pl = out.tabs["PLTE"].length / 3;            out.tabs[type] = [];            for (var i = 0; i < pl; i++) out.tabs[type].push(rUs(data, offset + i * 2));        } else if (type == "tRNS") {            if (out.ctype == 3) out.tabs[type] = bin.readBytes(data, offset, len);            else if (out.ctype == 0) out.tabs[type] = rUs(data, offset);            else if (out.ctype == 2) out.tabs[type] = [rUs(data, offset), rUs(data, offset + 2), rUs(data, offset + 4)];            //else console.log("tRNS for unsupported color type",out.ctype, len);        } else if (type == "gAMA") out.tabs[type] = bin.readUint(data, offset) / 100000;        else if (type == "sRGB") out.tabs[type] = data[offset];        else if (type == "bKGD") {            if (out.ctype == 0 || out.ctype == 4) out.tabs[type] = [rUs(data, offset)];            else if (out.ctype == 2 || out.ctype == 6) out.tabs[type] = [rUs(data, offset), rUs(data, offset + 2), rUs(data, offset + 4)];            else if (out.ctype == 3) out.tabs[type] = data[offset];        } else if (type == "IEND") {            break;        }        //else {  console.log("unknown chunk type", type, len);  out.tabs[type]=data.slice(offset,offset+len);  }        offset += len;        var crc = bin.readUint(data, offset);        offset += 4;    }    if (foff != 0) {        var fr = out.frames[out.frames.length - 1];        fr.data = UPNG.decode._decompress(out, fd.slice(0, foff), fr.rect.width, fr.rect.height);    }    out.data = UPNG.decode._decompress(out, dd, out.width, out.height);    delete out.compress;    delete out.interlace;    delete out.filter;    return out;}UPNG.decode._decompress = function (out, dd, w, h) {    var time = Date.now();    var bpp = UPNG.decode._getBPP(out),        bpl = Math.ceil(w * bpp / 8),        buff = new Uint8Array((bpl + 1 + out.interlace) * h);    if (out.tabs["CgBI"]) dd = UPNG.inflateRaw(dd, buff);    else dd = UPNG.decode._inflate(dd, buff);    //console.log(dd.length, buff.length);    //console.log(Date.now()-time);    var time = Date.now();    if (out.interlace == 0) dd = UPNG.decode._filterZero(dd, out, 0, w, h);    else if (out.interlace == 1) dd = UPNG.decode._readInterlace(dd, out);    //console.log(Date.now()-time);    return dd;}UPNG.decode._inflate = function (data, buff) {    var out = UPNG["inflateRaw"](new Uint8Array(data.buffer, 2, data.length - 6), buff);    return out;}UPNG.inflateRaw = function () {    var H = {};    H.H = {};    H.H.N = function (N, W) {        var R = Uint8Array,            i = 0,            m = 0,            J = 0,            h = 0,            Q = 0,            X = 0,            u = 0,            w = 0,            d = 0,            v, C;        if (N[0] == 3 && N[1] == 0) return W ? W : new R(0);        var V = H.H,            n = V.b,            A = V.e,            l = V.R,            M = V.n,            I = V.A,            e = V.Z,            b = V.m,            Z = W == null;        if (Z) W = new R(N.length >>> 2 << 5);        while (i == 0) {            i = n(N, d, 1);            m = n(N, d + 1, 2);            d += 3;            if (m == 0) {                if ((d & 7) != 0) d += 8 - (d & 7);                var D = (d >>> 3) + 4,                    q = N[D - 4] | N[D - 3] << 8;                if (Z) W = H.H.W(W, w + q);                W.set(new R(N.buffer, N.byteOffset + D, q), w);                d = D + q << 3;                w += q;                continue            }            if (Z) W = H.H.W(W, w + (1 << 17));            if (m == 1) {                v = b.J;                C = b.h;                X = (1 << 9) - 1;                u = (1 << 5) - 1            }            if (m == 2) {                J = A(N, d, 5) + 257;                h = A(N, d + 5, 5) + 1;                Q = A(N, d + 10, 4) + 4;                d += 14;                var E = d,                    j = 1;                for (var c = 0; c < 38; c += 2) {                    b.Q[c] = 0;                    b.Q[c + 1] = 0                }                for (var c = 0; c < Q; c++) {                    var K = A(N, d + c * 3, 3);                    b.Q[(b.X[c] << 1) + 1] = K;                    if (K > j) j = K                }                d += 3 * Q;                M(b.Q, j);                I(b.Q, j, b.u);                v = b.w;                C = b.d;                d = l(b.u, (1 << j) - 1, J + h, N, d, b.v);                var r = V.V(b.v, 0, J, b.C);                X = (1 << r) - 1;                var S = V.V(b.v, J, h, b.D);                u = (1 << S) - 1;                M(b.C, r);                I(b.C, r, v);                M(b.D, S);                I(b.D, S, C)            }            while (!0) {                var T = v[e(N, d) & X];                d += T & 15;                var p = T >>> 4;                if (p >>> 8 == 0) {                    W[w++] = p                } else if (p == 256) {                    break                } else {                    var z = w + p - 254;                    if (p > 264) {                        var _ = b.q[p - 257];                        z = w + (_ >>> 3) + A(N, d, _ & 7);                        d += _ & 7                    }                    var $ = C[e(N, d) & u];                    d += $ & 15;                    var s = $ >>> 4,                        Y = b.c[s],                        a = (Y >>> 4) + n(N, d, Y & 15);                    d += Y & 15;                    while (w < z) {                        W[w] = W[w++ - a];                        W[w] = W[w++ - a];                        W[w] = W[w++ - a];                        W[w] = W[w++ - a]                    }                    w = z                }            }        }        return W.length == w ? W : W.slice(0, w)    };    H.H.W = function (N, W) {        var R = N.length;        if (W <= R) return N;        var V = new Uint8Array(R << 1);        V.set(N, 0);        return V    };    H.H.R = function (N, W, R, V, n, A) {        var l = H.H.e,            M = H.H.Z,            I = 0;        while (I < R) {            var e = N[M(V, n) & W];            n += e & 15;            var b = e >>> 4;            if (b <= 15) {                A[I] = b;                I++            } else {                var Z = 0,                    m = 0;                if (b == 16) {                    m = 3 + l(V, n, 2);                    n += 2;                    Z = A[I - 1]                } else if (b == 17) {                    m = 3 + l(V, n, 3);                    n += 3                } else if (b == 18) {                    m = 11 + l(V, n, 7);                    n += 7                }                var J = I + m;                while (I < J) {                    A[I] = Z;                    I++                }            }        }        return n    };    H.H.V = function (N, W, R, V) {        var n = 0,            A = 0,            l = V.length >>> 1;        while (A < R) {            var M = N[A + W];            V[A << 1] = 0;            V[(A << 1) + 1] = M;            if (M > n) n = M;            A++        }        while (A < l) {            V[A << 1] = 0;            V[(A << 1) + 1] = 0;            A++        }        return n    };    H.H.n = function (N, W) {        var R = H.H.m,            V = N.length,            n, A, l, M, I, e = R.j;        for (var M = 0; M <= W; M++) e[M] = 0;        for (M = 1; M < V; M += 2) e[N[M]]++;        var b = R.K;        n = 0;        e[0] = 0;        for (A = 1; A <= W; A++) {            n = n + e[A - 1] << 1;            b[A] = n        }        for (l = 0; l < V; l += 2) {            I = N[l + 1];            if (I != 0) {                N[l] = b[I];                b[I]++            }        }    };    H.H.A = function (N, W, R) {        var V = N.length,            n = H.H.m,            A = n.r;        for (var l = 0; l < V; l += 2)            if (N[l + 1] != 0) {                var M = l >> 1,                    I = N[l + 1],                    e = M << 4 | I,                    b = W - I,                    Z = N[l] << b,                    m = Z + (1 << b);                while (Z != m) {                    var J = A[Z] >>> 15 - W;                    R[J] = e;                    Z++                }            }    };    H.H.l = function (N, W) {        var R = H.H.m.r,            V = 15 - W;        for (var n = 0; n < N.length; n += 2) {            var A = N[n] << W - N[n + 1];            N[n] = R[A] >>> V        }    };    H.H.M = function (N, W, R) {        R = R << (W & 7);        var V = W >>> 3;        N[V] |= R;        N[V + 1] |= R >>> 8    };    H.H.I = function (N, W, R) {        R = R << (W & 7);        var V = W >>> 3;        N[V] |= R;        N[V + 1] |= R >>> 8;        N[V + 2] |= R >>> 16    };    H.H.e = function (N, W, R) {        return (N[W >>> 3] | N[(W >>> 3) + 1] << 8) >>> (W & 7) & (1 << R) - 1    };    H.H.b = function (N, W, R) {        return (N[W >>> 3] | N[(W >>> 3) + 1] << 8 | N[(W >>> 3) + 2] << 16) >>> (W & 7) & (1 << R) - 1    };    H.H.Z = function (N, W) {        return (N[W >>> 3] | N[(W >>> 3) + 1] << 8 | N[(W >>> 3) + 2] << 16) >>> (W & 7)    };    H.H.i = function (N, W) {        return (N[W >>> 3] | N[(W >>> 3) + 1] << 8 | N[(W >>> 3) + 2] << 16 | N[(W >>> 3) + 3] << 24) >>> (W & 7)    };    H.H.m = function () {        var N = Uint16Array,            W = Uint32Array;        return {            K: new N(16),            j: new N(16),            X: [16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15],            S: [3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 999, 999, 999],            T: [0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 0, 0, 0],            q: new N(32),            p: [1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577, 65535, 65535],            z: [0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13, 0, 0],            c: new W(32),            J: new N(512),            _: [],            h: new N(32),            $: [],            w: new N(32768),            C: [],            v: [],            d: new N(32768),            D: [],            u: new N(512),            Q: [],            r: new N(1 << 15),            s: new W(286),            Y: new W(30),            a: new W(19),            t: new W(15e3),            k: new N(1 << 16),            g: new N(1 << 15)        }    }();    (function () {        var N = H.H.m,            W = 1 << 15;        for (var R = 0; R < W; R++) {            var V = R;            V = (V & 2863311530) >>> 1 | (V & 1431655765) << 1;            V = (V & 3435973836) >>> 2 | (V & 858993459) << 2;            V = (V & 4042322160) >>> 4 | (V & 252645135) << 4;            V = (V & 4278255360) >>> 8 | (V & 16711935) << 8;            N.r[R] = (V >>> 16 | V << 16) >>> 17        }        function n(A, l, M) {            while (l-- != 0) A.push(0, M)        }        for (var R = 0; R < 32; R++) {            N.q[R] = N.S[R] << 3 | N.T[R];            N.c[R] = N.p[R] << 4 | N.z[R]        }        n(N._, 144, 8);        n(N._, 255 - 143, 9);        n(N._, 279 - 255, 7);        n(N._, 287 - 279, 8);        H.H.n(N._, 9);        H.H.A(N._, 9, N.J);        H.H.l(N._, 9);        n(N.$, 32, 5);        H.H.n(N.$, 5);        H.H.A(N.$, 5, N.h);        H.H.l(N.$, 5);        n(N.Q, 19, 0);        n(N.C, 286, 0);        n(N.D, 30, 0);        n(N.v, 320, 0)    }());    return H.H.N}()UPNG.decode._readInterlace = function (data, out) {    var w = out.width,        h = out.height;    var bpp = UPNG.decode._getBPP(out),        cbpp = bpp >> 3,        bpl = Math.ceil(w * bpp / 8);    var img = new Uint8Array(h * bpl);    var di = 0;    var starting_row = [0, 0, 4, 0, 2, 0, 1];    var starting_col = [0, 4, 0, 2, 0, 1, 0];    var row_increment = [8, 8, 8, 4, 4, 2, 2];    var col_increment = [8, 8, 4, 4, 2, 2, 1];    var pass = 0;    while (pass < 7) {        var ri = row_increment[pass],            ci = col_increment[pass];        var sw = 0,            sh = 0;        var cr = starting_row[pass];        while (cr < h) {            cr += ri;            sh++;        }        var cc = starting_col[pass];        while (cc < w) {            cc += ci;            sw++;        }        var bpll = Math.ceil(sw * bpp / 8);        UPNG.decode._filterZero(data, out, di, sw, sh);        var y = 0,            row = starting_row[pass];        while (row < h) {            var col = starting_col[pass];            var cdi = (di + y * bpll) << 3;            while (col < w) {                if (bpp == 1) {                    var val = data[cdi >> 3];                    val = (val >> (7 - (cdi & 7))) & 1;                    img[row * bpl + (col >> 3)] |= (val << (7 - ((col & 7) << 0)));                }                if (bpp == 2) {                    var val = data[cdi >> 3];                    val = (val >> (6 - (cdi & 7))) & 3;                    img[row * bpl + (col >> 2)] |= (val << (6 - ((col & 3) << 1)));                }                if (bpp == 4) {                    var val = data[cdi >> 3];                    val = (val >> (4 - (cdi & 7))) & 15;                    img[row * bpl + (col >> 1)] |= (val << (4 - ((col & 1) << 2)));                }                if (bpp >= 8) {                    var ii = row * bpl + col * cbpp;                    for (var j = 0; j < cbpp; j++) img[ii + j] = data[(cdi >> 3) + j];                }                cdi += bpp;                col += ci;            }            y++;            row += ri;        }        if (sw * sh != 0) di += sh * (1 + bpll);        pass = pass + 1;    }    return img;}UPNG.decode._getBPP = function (out) {    var noc = [1, null, 3, 1, 2, null, 4][out.ctype];    return noc * out.depth;}UPNG.decode._filterZero = function (data, out, off, w, h) {    var bpp = UPNG.decode._getBPP(out),        bpl = Math.ceil(w * bpp / 8),        paeth = UPNG.decode._paeth;    bpp = Math.ceil(bpp / 8);    var i, di, type = data[off],        x = 0;    if (type > 1) data[off] = [0, 0, 1][type - 2];    if (type == 3)        for (x = bpp; x < bpl; x++) data[x + 1] = (data[x + 1] + (data[x + 1 - bpp] >>> 1)) & 255;    for (var y = 0; y < h; y++) {        i = off + y * bpl;        di = i + y + 1;        type = data[di - 1];        x = 0;        if (type == 0)            for (; x < bpl; x++) data[i + x] = data[di + x];        else if (type == 1) {            for (; x < bpp; x++) data[i + x] = data[di + x];            for (; x < bpl; x++) data[i + x] = (data[di + x] + data[i + x - bpp]);        } else if (type == 2) {            for (; x < bpl; x++) data[i + x] = (data[di + x] + data[i + x - bpl]);        } else if (type == 3) {            for (; x < bpp; x++) data[i + x] = (data[di + x] + (data[i + x - bpl] >>> 1));            for (; x < bpl; x++) data[i + x] = (data[di + x] + ((data[i + x - bpl] + data[i + x - bpp]) >>> 1));        } else {            for (; x < bpp; x++) data[i + x] = (data[di + x] + paeth(0, data[i + x - bpl], 0));            for (; x < bpl; x++) data[i + x] = (data[di + x] + paeth(data[i + x - bpp], data[i + x - bpl], data[i + x - bpp - bpl]));        }    }    return data;}UPNG.decode._paeth = function (a, b, c) {    var p = a + b - c,        pa = (p - a),        pb = (p - b),        pc = (p - c);    if (pa * pa <= pb * pb && pa * pa <= pc * pc) return a;    else if (pb * pb <= pc * pc) return b;    return c;}UPNG.decode._IHDR = function (data, offset, out) {    var bin = UPNG._bin;    out.width = bin.readUint(data, offset);    offset += 4;    out.height = bin.readUint(data, offset);    offset += 4;    out.depth = data[offset];    offset++;    out.ctype = data[offset];    offset++;    out.compress = data[offset];    offset++;    out.filter = data[offset];    offset++;    out.interlace = data[offset];    offset++;}UPNG._bin = {    nextZero: function (data, p) {        while (data[p] != 0) p++;        return p;    },    readUshort: function (buff, p) {        return (buff[p] << 8) | buff[p + 1];    },    writeUshort: function (buff, p, n) {        buff[p] = (n >> 8) & 255;        buff[p + 1] = n & 255;    },    readUint: function (buff, p) {        return (buff[p] * (256 * 256 * 256)) + ((buff[p + 1] << 16) | (buff[p + 2] << 8) | buff[p + 3]);    },    writeUint: function (buff, p, n) {        buff[p] = (n >> 24) & 255;        buff[p + 1] = (n >> 16) & 255;        buff[p + 2] = (n >> 8) & 255;        buff[p + 3] = n & 255;    },    readASCII: function (buff, p, l) {        var s = "";        for (var i = 0; i < l; i++) s += String.fromCharCode(buff[p + i]);        return s;    },    writeASCII: function (data, p, s) {        for (var i = 0; i < s.length; i++) data[p + i] = s.charCodeAt(i);    },    readBytes: function (buff, p, l) {        var arr = [];        for (var i = 0; i < l; i++) arr.push(buff[p + i]);        return arr;    },    pad: function (n) {        return n.length < 2 ? "0" + n : n;    },    readUTF8: function (buff, p, l) {        var s = "",            ns;        for (var i = 0; i < l; i++) s += "%" + UPNG._bin.pad(buff[p + i].toString(16));        try {            ns = decodeURIComponent(s);        } catch (e) {            return UPNG._bin.readASCII(buff, p, l);        }        return ns;    }}UPNG._copyTile = function (sb, sw, sh, tb, tw, th, xoff, yoff, mode) {    var w = Math.min(sw, tw),        h = Math.min(sh, th);    var si = 0,        ti = 0;    for (var y = 0; y < h; y++)        for (var x = 0; x < w; x++) {            if (xoff >= 0 && yoff >= 0) {                si = (y * sw + x) << 2;                ti = ((yoff + y) * tw + xoff + x) << 2;            } else {                si = ((-yoff + y) * sw - xoff + x) << 2;                ti = (y * tw + x) << 2;            }            if (mode == 0) {                tb[ti] = sb[si];                tb[ti + 1] = sb[si + 1];                tb[ti + 2] = sb[si + 2];                tb[ti + 3] = sb[si + 3];            } else if (mode == 1) {                var fa = sb[si + 3] * (1 / 255),                    fr = sb[si] * fa,                    fg = sb[si + 1] * fa,                    fb = sb[si + 2] * fa;                var ba = tb[ti + 3] * (1 / 255),                    br = tb[ti] * ba,                    bg = tb[ti + 1] * ba,                    bb = tb[ti + 2] * ba;                var ifa = 1 - fa,                    oa = fa + ba * ifa,                    ioa = (oa == 0 ? 0 : 1 / oa);                tb[ti + 3] = 255 * oa;                tb[ti + 0] = (fr + br * ifa) * ioa;                tb[ti + 1] = (fg + bg * ifa) * ioa;                tb[ti + 2] = (fb + bb * ifa) * ioa;            } else if (mode == 2) { // copy only differences, otherwise zero                var fa = sb[si + 3],                    fr = sb[si],                    fg = sb[si + 1],                    fb = sb[si + 2];                var ba = tb[ti + 3],                    br = tb[ti],                    bg = tb[ti + 1],                    bb = tb[ti + 2];                if (fa == ba && fr == br && fg == bg && fb == bb) {                    tb[ti] = 0;                    tb[ti + 1] = 0;                    tb[ti + 2] = 0;                    tb[ti + 3] = 0;                } else {                    tb[ti] = fr;                    tb[ti + 1] = fg;                    tb[ti + 2] = fb;                    tb[ti + 3] = fa;                }            } else if (mode == 3) { // check if can be blended                var fa = sb[si + 3],                    fr = sb[si],                    fg = sb[si + 1],                    fb = sb[si + 2];                var ba = tb[ti + 3],                    br = tb[ti],                    bg = tb[ti + 1],                    bb = tb[ti + 2];                if (fa == ba && fr == br && fg == bg && fb == bb) continue;                //if(fa!=255 && ba!=0) return false;                if (fa < 220 && ba > 20) return false;            }        }    return true;}UPNG.encode = function (bufs, w, h, ps, dels, tabs, forbidPlte) {    if (ps == null) ps = 0;    if (forbidPlte == null) forbidPlte = false;    var nimg = UPNG.encode.compress(bufs, w, h, ps, [false, false, false, 0, forbidPlte, false]);    UPNG.encode.compressPNG(nimg, -1);    return UPNG.encode._main(nimg, w, h, dels, tabs);}UPNG.encodeLL = function (bufs, w, h, cc, ac, depth, dels, tabs) {    var nimg = {        ctype: 0 + (cc == 1 ? 0 : 2) + (ac == 0 ? 0 : 4),        depth: depth,        frames: []    };    var time = Date.now();    var bipp = (cc + ac) * depth,        bipl = bipp * w;    for (var i = 0; i < bufs.length; i++)        nimg.frames.push({            rect: {                x: 0,                y: 0,                width: w,                height: h            },            img: new Uint8Array(bufs[i]),            blend: 0,            dispose: 1,            bpp: Math.ceil(bipp / 8),            bpl: Math.ceil(bipl / 8)        });    UPNG.encode.compressPNG(nimg, 0, true);    var out = UPNG.encode._main(nimg, w, h, dels, tabs);    return out;}UPNG.encode._main = function (nimg, w, h, dels, tabs) {    if (tabs == null) tabs = {};    var crc = UPNG.crc.crc,        wUi = UPNG._bin.writeUint,        wUs = UPNG._bin.writeUshort,        wAs = UPNG._bin.writeASCII;    var offset = 8,        anim = nimg.frames.length > 1,        pltAlpha = false;    var leng = 8 + (16 + 5 + 4) /*+ (9+4)*/ + (anim ? 20 : 0);    if (tabs["sRGB"] != null) leng += 8 + 1 + 4;    if (tabs["pHYs"] != null) leng += 8 + 9 + 4;    if (nimg.ctype == 3) {        var dl = nimg.plte.length;        for (var i = 0; i < dl; i++)            if ((nimg.plte[i] >>> 24) != 255) pltAlpha = true;        leng += (8 + dl * 3 + 4) + (pltAlpha ? (8 + dl * 1 + 4) : 0);    }    for (var j = 0; j < nimg.frames.length; j++) {        var fr = nimg.frames[j];        if (anim) leng += 38;        leng += fr.cimg.length + 12;        if (j != 0) leng += 4;    }    leng += 12;    var data = new Uint8Array(leng);    var wr = [0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a];    for (var i = 0; i < 8; i++) data[i] = wr[i];    wUi(data, offset, 13);    offset += 4;    wAs(data, offset, "IHDR");    offset += 4;    wUi(data, offset, w);    offset += 4;    wUi(data, offset, h);    offset += 4;    data[offset] = nimg.depth;    offset++; // depth    data[offset] = nimg.ctype;    offset++; // ctype    data[offset] = 0;    offset++; // compress    data[offset] = 0;    offset++; // filter    data[offset] = 0;    offset++; // interlace    wUi(data, offset, crc(data, offset - 17, 17));    offset += 4; // crc    // 13 bytes to say, that it is sRGB    if (tabs["sRGB"] != null) {        wUi(data, offset, 1);        offset += 4;        wAs(data, offset, "sRGB");        offset += 4;        data[offset] = tabs["sRGB"];        offset++;        wUi(data, offset, crc(data, offset - 5, 5));        offset += 4; // crc    }    if (tabs["pHYs"] != null) {        wUi(data, offset, 9);        offset += 4;        wAs(data, offset, "pHYs");        offset += 4;        wUi(data, offset, tabs["pHYs"][0]);        offset += 4;        wUi(data, offset, tabs["pHYs"][1]);        offset += 4;        data[offset] = tabs["pHYs"][2];        offset++;        wUi(data, offset, crc(data, offset - 13, 13));        offset += 4; // crc    }    if (anim) {        wUi(data, offset, 8);        offset += 4;        wAs(data, offset, "acTL");        offset += 4;        wUi(data, offset, nimg.frames.length);        offset += 4;        wUi(data, offset, tabs["loop"] != null ? tabs["loop"] : 0);        offset += 4;        wUi(data, offset, crc(data, offset - 12, 12));        offset += 4; // crc    }    if (nimg.ctype == 3) {        var dl = nimg.plte.length;        wUi(data, offset, dl * 3);        offset += 4;        wAs(data, offset, "PLTE");        offset += 4;        for (var i = 0; i < dl; i++) {            var ti = i * 3,                c = nimg.plte[i],                r = (c) & 255,                g = (c >>> 8) & 255,                b = (c >>> 16) & 255;            data[offset + ti + 0] = r;            data[offset + ti + 1] = g;            data[offset + ti + 2] = b;        }        offset += dl * 3;        wUi(data, offset, crc(data, offset - dl * 3 - 4, dl * 3 + 4));        offset += 4; // crc        if (pltAlpha) {            wUi(data, offset, dl);            offset += 4;            wAs(data, offset, "tRNS");            offset += 4;            for (var i = 0; i < dl; i++) data[offset + i] = (nimg.plte[i] >>> 24) & 255;            offset += dl;            wUi(data, offset, crc(data, offset - dl - 4, dl + 4));            offset += 4; // crc        }    }    var fi = 0;    for (var j = 0; j < nimg.frames.length; j++) {        var fr = nimg.frames[j];        if (anim) {            wUi(data, offset, 26);            offset += 4;            wAs(data, offset, "fcTL");            offset += 4;            wUi(data, offset, fi++);            offset += 4;            wUi(data, offset, fr.rect.width);            offset += 4;            wUi(data, offset, fr.rect.height);            offset += 4;            wUi(data, offset, fr.rect.x);            offset += 4;            wUi(data, offset, fr.rect.y);            offset += 4;            wUs(data, offset, dels[j]);            offset += 2;            wUs(data, offset, 1000);            offset += 2;            data[offset] = fr.dispose;            offset++; // dispose            data[offset] = fr.blend;            offset++; // blend            wUi(data, offset, crc(data, offset - 30, 30));            offset += 4; // crc        }        var imgd = fr.cimg,            dl = imgd.length;        wUi(data, offset, dl + (j == 0 ? 0 : 4));        offset += 4;        var ioff = offset;        wAs(data, offset, (j == 0) ? "IDAT" : "fdAT");        offset += 4;        if (j != 0) {            wUi(data, offset, fi++);            offset += 4;        }        data.set(imgd, offset);        offset += dl;        wUi(data, offset, crc(data, ioff, offset - ioff));        offset += 4; // crc    }    wUi(data, offset, 0);    offset += 4;    wAs(data, offset, "IEND");    offset += 4;    wUi(data, offset, crc(data, offset - 4, 4));    offset += 4; // crc    return data.buffer;}UPNG.encode.compressPNG = function (out, filter, levelZero) {    for (var i = 0; i < out.frames.length; i++) {        var frm = out.frames[i],            nw = frm.rect.width,            nh = frm.rect.height;        var fdata = new Uint8Array(nh * frm.bpl + nh);        frm.cimg = UPNG.encode._filterZero(frm.img, nh, frm.bpp, frm.bpl, fdata, filter, levelZero);    }}UPNG.encode.compress = function (bufs, w, h, ps, prms) // prms:  onlyBlend, minBits, forbidPlte{    //var time = Date.now();    var onlyBlend = prms[0],        evenCrd = prms[1],        forbidPrev = prms[2],        minBits = prms[3],        forbidPlte = prms[4],        dither = prms[5];    var ctype = 6,        depth = 8,        alphaAnd = 255    for (var j = 0; j < bufs.length; j++) { // when not quantized, other frames can contain colors, that are not in an initial frame        var img = new Uint8Array(bufs[j]),            ilen = img.length;        for (var i = 0; i < ilen; i += 4) alphaAnd &= img[i + 3];    }    var gotAlpha = (alphaAnd != 255);    //console.log("alpha check", Date.now()-time);  time = Date.now();    //var brute = gotAlpha && forGIF;// brute : frames can only be copied, not "blended"    var frms = UPNG.encode.framize(bufs, w, h, onlyBlend, evenCrd, forbidPrev);    //console.log("framize", Date.now()-time);  time = Date.now();    var cmap = {},        plte = [],        inds = [];    if (ps != 0) {        var nbufs = [];        for (var i = 0; i < frms.length; i++) nbufs.push(frms[i].img.buffer);        var abuf = UPNG.encode.concatRGBA(nbufs),            qres = UPNG.quantize(abuf, ps);        for (var i = 0; i < qres.plte.length; i++) plte.push(qres.plte[i].est.rgba);        var cof = 0;        for (var i = 0; i < frms.length; i++) {            var frm = frms[i],                bln = frm.img.length,                ind = new Uint8Array(qres.inds.buffer, cof >> 2, bln >> 2);            inds.push(ind);            var bb = new Uint8Array(qres.abuf, cof, bln);            //console.log(frm.img, frm.width, frm.height);            //var time = Date.now();            if (dither) UPNG.encode.dither(frm.img, frm.rect.width, frm.rect.height, plte, bb, ind);            //console.log(Date.now()-time);            frm.img.set(bb);            cof += bln;        }        //console.log("quantize", Date.now()-time);  time = Date.now();    } else {        // what if ps==0, but there are <=256 colors?  we still need to detect, if the palette could be used        for (var j = 0; j < frms.length; j++) { // when not quantized, other frames can contain colors, that are not in an initial frame            var frm = frms[j],                img32 = new Uint32Array(frm.img.buffer),                nw = frm.rect.width,                ilen = img32.length;            var ind = new Uint8Array(ilen);            inds.push(ind);            for (var i = 0; i < ilen; i++) {                var c = img32[i];                if (i != 0 && c == img32[i - 1]) ind[i] = ind[i - 1];                else if (i > nw && c == img32[i - nw]) ind[i] = ind[i - nw];                else {                    var cmc = cmap[c];                    if (cmc == null) {                        cmap[c] = cmc = plte.length;                        plte.push(c);                        if (plte.length >= 300) break;                    }                    ind[i] = cmc;                }            }        }        //console.log("make palette", Date.now()-time);  time = Date.now();    }    var cc = plte.length; //console.log("colors:",cc);    if (cc <= 256 && forbidPlte == false) {        if (cc <= 2) depth = 1;        else if (cc <= 4) depth = 2;        else if (cc <= 16) depth = 4;        else depth = 8;        depth = Math.max(depth, minBits);    }    for (var j = 0; j < frms.length; j++) {        var frm = frms[j],            nx = frm.rect.x,            ny = frm.rect.y,            nw = frm.rect.width,            nh = frm.rect.height;        var cimg = frm.img,            cimg32 = new Uint32Array(cimg.buffer);        var bpl = 4 * nw,            bpp = 4;        if (cc <= 256 && forbidPlte == false) {            bpl = Math.ceil(depth * nw / 8);            var nimg = new Uint8Array(bpl * nh);            var inj = inds[j];            for (var y = 0; y < nh; y++) {                var i = y * bpl,                    ii = y * nw;                if (depth == 8)                    for (var x = 0; x < nw; x++) nimg[i + (x)] = (inj[ii + x]);                else if (depth == 4)                    for (var x = 0; x < nw; x++) nimg[i + (x >> 1)] |= (inj[ii + x] << (4 - (x & 1) * 4));                else if (depth == 2)                    for (var x = 0; x < nw; x++) nimg[i + (x >> 2)] |= (inj[ii + x] << (6 - (x & 3) * 2));                else if (depth == 1)                    for (var x = 0; x < nw; x++) nimg[i + (x >> 3)] |= (inj[ii + x] << (7 - (x & 7) * 1));            }            cimg = nimg;            ctype = 3;            bpp = 1;        } else if (gotAlpha == false && frms.length == 1) { // some next "reduced" frames may contain alpha for blending            var nimg = new Uint8Array(nw * nh * 3),                area = nw * nh;            for (var i = 0; i < area; i++) {                var ti = i * 3,                    qi = i * 4;                nimg[ti] = cimg[qi];                nimg[ti + 1] = cimg[qi + 1];                nimg[ti + 2] = cimg[qi + 2];            }            cimg = nimg;            ctype = 2;            bpp = 3;            bpl = 3 * nw;        }        frm.img = cimg;        frm.bpl = bpl;        frm.bpp = bpp;    }    //console.log("colors => palette indices", Date.now()-time);  time = Date.now();    return {        ctype: ctype,        depth: depth,        plte: plte,        frames: frms    };}UPNG.encode.framize = function (bufs, w, h, alwaysBlend, evenCrd, forbidPrev) {    /*  DISPOSE        - 0 : no change    - 1 : clear to transparent    - 2 : retstore to content before rendering (previous frame disposed)    BLEND    - 0 : replace    - 1 : blend    */    var frms = [];    for (var j = 0; j < bufs.length; j++) {        var cimg = new Uint8Array(bufs[j]),            cimg32 = new Uint32Array(cimg.buffer);        var nimg;        var nx = 0,            ny = 0,            nw = w,            nh = h,            blend = alwaysBlend ? 1 : 0;        if (j != 0) {            var tlim = (forbidPrev || alwaysBlend || j == 1 || frms[j - 2].dispose != 0) ? 1 : 2,                tstp = 0,                tarea = 1e9;            for (var it = 0; it < tlim; it++) {                var pimg = new Uint8Array(bufs[j - 1 - it]),                    p32 = new Uint32Array(bufs[j - 1 - it]);                var mix = w,                    miy = h,                    max = -1,                    may = -1;                for (var y = 0; y < h; y++)                    for (var x = 0; x < w; x++) {                        var i = y * w + x;                        if (cimg32[i] != p32[i]) {                            if (x < mix) mix = x;                            if (x > max) max = x;                            if (y < miy) miy = y;                            if (y > may) may = y;                        }                    }                if (max == -1) mix = miy = max = may = 0;                if (evenCrd) {                    if ((mix & 1) == 1) mix--;                    if ((miy & 1) == 1) miy--;                }                var sarea = (max - mix + 1) * (may - miy + 1);                if (sarea < tarea) {                    tarea = sarea;                    tstp = it;                    nx = mix;                    ny = miy;                    nw = max - mix + 1;                    nh = may - miy + 1;                }            }            // alwaysBlend: pokud zjistím, že blendit nelze, nastavím předchozímu snímku dispose=1. Zajistím, aby obsahoval můj obdélník.            var pimg = new Uint8Array(bufs[j - 1 - tstp]);            if (tstp == 1) frms[j - 1].dispose = 2;            nimg = new Uint8Array(nw * nh * 4);            UPNG._copyTile(pimg, w, h, nimg, nw, nh, -nx, -ny, 0);            blend = UPNG._copyTile(cimg, w, h, nimg, nw, nh, -nx, -ny, 3) ? 1 : 0;            if (blend == 1) UPNG.encode._prepareDiff(cimg, w, h, nimg, {                x: nx,                y: ny,                width: nw,                height: nh            });            else UPNG._copyTile(cimg, w, h, nimg, nw, nh, -nx, -ny, 0);            //UPNG._copyTile(cimg,w,h, nimg,nw,nh, -nx,-ny, blend==1?2:0);        } else nimg = cimg.slice(0); // img may be rewritten further ... don't rewrite input        frms.push({            rect: {                x: nx,                y: ny,                width: nw,                height: nh            },            img: nimg,            blend: blend,            dispose: 0        });    }    if (alwaysBlend)        for (var j = 0; j < frms.length; j++) {            var frm = frms[j];            if (frm.blend == 1) continue;            var r0 = frm.rect,                r1 = frms[j - 1].rect            var miX = Math.min(r0.x, r1.x),                miY = Math.min(r0.y, r1.y);            var maX = Math.max(r0.x + r0.width, r1.x + r1.width),                maY = Math.max(r0.y + r0.height, r1.y + r1.height);            var r = {                x: miX,                y: miY,                width: maX - miX,                height: maY - miY            };            frms[j - 1].dispose = 1;            if (j - 1 != 0)                UPNG.encode._updateFrame(bufs, w, h, frms, j - 1, r, evenCrd);            UPNG.encode._updateFrame(bufs, w, h, frms, j, r, evenCrd);        }    var area = 0;    if (bufs.length != 1)        for (var i = 0; i < frms.length; i++) {            var frm = frms[i];            area += frm.rect.width * frm.rect.height;            //if(i==0 || frm.blend!=1) continue;            //var ob = new Uint8Array(            //console.log(frm.blend, frm.dispose, frm.rect);        }    //if(area!=0) console.log(area);    return frms;}UPNG.encode._updateFrame = function (bufs, w, h, frms, i, r, evenCrd) {    var U8 = Uint8Array,        U32 = Uint32Array;    var pimg = new U8(bufs[i - 1]),        pimg32 = new U32(bufs[i - 1]),        nimg = i + 1 < bufs.length ? new U8(bufs[i + 1]) : null;    var cimg = new U8(bufs[i]),        cimg32 = new U32(cimg.buffer);    var mix = w,        miy = h,        max = -1,        may = -1;    for (var y = 0; y < r.height; y++)        for (var x = 0; x < r.width; x++) {            var cx = r.x + x,                cy = r.y + y;            var j = cy * w + cx,                cc = cimg32[j];            // no need to draw transparency, or to dispose it. Or, if writing the same color and the next one does not need transparency.            if (cc == 0 || (frms[i - 1].dispose == 0 && pimg32[j] == cc && (nimg == null || nimg[j * 4 + 3] != 0)) /**/ ) {} else {                if (cx < mix) mix = cx;                if (cx > max) max = cx;                if (cy < miy) miy = cy;                if (cy > may) may = cy;            }        }    if (max == -1) mix = miy = max = may = 0;    if (evenCrd) {        if ((mix & 1) == 1) mix--;        if ((miy & 1) == 1) miy--;    }    r = {        x: mix,        y: miy,        width: max - mix + 1,        height: may - miy + 1    };    var fr = frms[i];    fr.rect = r;    fr.blend = 1;    fr.img = new Uint8Array(r.width * r.height * 4);    if (frms[i - 1].dispose == 0) {        UPNG._copyTile(pimg, w, h, fr.img, r.width, r.height, -r.x, -r.y, 0);        UPNG.encode._prepareDiff(cimg, w, h, fr.img, r);        //UPNG._copyTile(cimg,w,h, fr.img,r.width,r.height, -r.x,-r.y, 2);    } else        UPNG._copyTile(cimg, w, h, fr.img, r.width, r.height, -r.x, -r.y, 0);}UPNG.encode._prepareDiff = function (cimg, w, h, nimg, rec) {    UPNG._copyTile(cimg, w, h, nimg, rec.width, rec.height, -rec.x, -rec.y, 2);    /*    var n32 = new Uint32Array(nimg.buffer);    var og = new Uint8Array(rec.width*rec.height*4), o32 = new Uint32Array(og.buffer);    UPNG._copyTile(cimg,w,h, og,rec.width,rec.height, -rec.x,-rec.y, 0);    for(var i=4; i<nimg.length; i+=4) {    if(nimg[i-1]!=0 && nimg[i+3]==0 && o32[i>>>2]==o32[(i>>>2)-1]) {    n32[i>>>2]=o32[i>>>2];    //var j = i, c=p32[(i>>>2)-1];    //while(p32[j>>>2]==c) {  n32[j>>>2]=c;  j+=4;  }    }    }    for(var i=nimg.length-8; i>0; i-=4) {    if(nimg[i+7]!=0 && nimg[i+3]==0 && o32[i>>>2]==o32[(i>>>2)+1]) {    n32[i>>>2]=o32[i>>>2];    //var j = i, c=p32[(i>>>2)-1];    //while(p32[j>>>2]==c) {  n32[j>>>2]=c;  j+=4;  }    }    }*/}UPNG.encode._filterZero = function (img, h, bpp, bpl, data, filter, levelZero) {    var fls = [],        ftry = [0, 1, 2, 3, 4];    if (filter != -1) ftry = [filter];    else if (h * bpl > 500000 || bpp == 1) ftry = [0];    var opts;    if (levelZero) opts = {        level: 0    };    var CMPR = (data.length > 10e6 && UZIP != null) ? UZIP : pako;    var time = Date.now();    for (var i = 0; i < ftry.length; i++) {        for (var y = 0; y < h; y++) UPNG.encode._filterLine(data, img, y, bpl, bpp, ftry[i]);        //var nimg = new Uint8Array(data.length);        //var sz = UZIP.F.deflate(data, nimg);  fls.push(nimg.slice(0,sz));        //var dfl = pako["deflate"](data), dl=dfl.length-4;        //var crc = (dfl[dl+3]<<24)|(dfl[dl+2]<<16)|(dfl[dl+1]<<8)|(dfl[dl+0]<<0);        //console.log(crc, UZIP.adler(data,2,data.length-6));        fls.push(CMPR["deflate"](data, opts));    }    var ti, tsize = 1e9;    for (var i = 0; i < fls.length; i++)        if (fls[i].length < tsize) {            ti = i;            tsize = fls[i].length;        }    return fls[ti];}UPNG.encode._filterLine = function (data, img, y, bpl, bpp, type) {    var i = y * bpl,        di = i + y,        paeth = UPNG.decode._paeth    data[di] = type;    di++;    if (type == 0) {        if (bpl < 500)            for (var x = 0; x < bpl; x++) data[di + x] = img[i + x];        else data.set(new Uint8Array(img.buffer, i, bpl), di);    } else if (type == 1) {        for (var x = 0; x < bpp; x++) data[di + x] = img[i + x];        for (var x = bpp; x < bpl; x++) data[di + x] = (img[i + x] - img[i + x - bpp] + 256) & 255;    } else if (y == 0) {        for (var x = 0; x < bpp; x++) data[di + x] = img[i + x];        if (type == 2)            for (var x = bpp; x < bpl; x++) data[di + x] = img[i + x];        if (type == 3)            for (var x = bpp; x < bpl; x++) data[di + x] = (img[i + x] - (img[i + x - bpp] >> 1) + 256) & 255;        if (type == 4)            for (var x = bpp; x < bpl; x++) data[di + x] = (img[i + x] - paeth(img[i + x - bpp], 0, 0) + 256) & 255;    } else {        if (type == 2) {            for (var x = 0; x < bpl; x++) data[di + x] = (img[i + x] + 256 - img[i + x - bpl]) & 255;        }        if (type == 3) {            for (var x = 0; x < bpp; x++) data[di + x] = (img[i + x] + 256 - (img[i + x - bpl] >> 1)) & 255;            for (var x = bpp; x < bpl; x++) data[di + x] = (img[i + x] + 256 - ((img[i + x - bpl] + img[i + x - bpp]) >> 1)) & 255;        }        if (type == 4) {            for (var x = 0; x < bpp; x++) data[di + x] = (img[i + x] + 256 - paeth(0, img[i + x - bpl], 0)) & 255;            for (var x = bpp; x < bpl; x++) data[di + x] = (img[i + x] + 256 - paeth(img[i + x - bpp], img[i + x - bpl], img[i + x - bpp - bpl])) & 255;        }    }}UPNG.crc = {    table: (function () {        var tab = new Uint32Array(256);        for (var n = 0; n < 256; n++) {            var c = n;            for (var k = 0; k < 8; k++) {                if (c & 1) c = 0xedb88320 ^ (c >>> 1);                else c = c >>> 1;            }            tab[n] = c;        }        return tab;    })(),    update: function (c, buf, off, len) {        for (var i = 0; i < len; i++) c = UPNG.crc.table[(c ^ buf[off + i]) & 0xff] ^ (c >>> 8);        return c;    },    crc: function (b, o, l) {        return UPNG.crc.update(0xffffffff, b, o, l) ^ 0xffffffff;    }}UPNG.quantize = function (abuf, ps) {    var sb = new Uint8Array(abuf),        tb = sb.slice(0),        tb32 = new Uint32Array(tb.buffer);    var KD = UPNG.quantize.getKDtree(tb, ps);    var root = KD[0],        leafs = KD[1];    var planeDst = UPNG.quantize.planeDst;    var len = sb.length;    var inds = new Uint8Array(len >> 2),        nd;    if (sb.length < 20e6) // precise, but slow :(        for (var i = 0; i < len; i += 4) {            var r = sb[i] * (1 / 255),                g = sb[i + 1] * (1 / 255),                b = sb[i + 2] * (1 / 255),                a = sb[i + 3] * (1 / 255);            nd = UPNG.quantize.getNearest(root, r, g, b, a);            inds[i >> 2] = nd.ind;            tb32[i >> 2] = nd.est.rgba;        }    else        for (var i = 0; i < len; i += 4) {            var r = sb[i] * (1 / 255),                g = sb[i + 1] * (1 / 255),                b = sb[i + 2] * (1 / 255),                a = sb[i + 3] * (1 / 255);            nd = root;            while (nd.left) nd = (planeDst(nd.est, r, g, b, a) <= 0) ? nd.left : nd.right;            inds[i >> 2] = nd.ind;            tb32[i >> 2] = nd.est.rgba;        }    return {        abuf: tb.buffer,        inds: inds,        plte: leafs    };}UPNG.quantize.getKDtree = function (nimg, ps, err) {    if (err == null) err = 0.0001;    var nimg32 = new Uint32Array(nimg.buffer);    var root = {        i0: 0,        i1: nimg.length,        bst: null,        est: null,        tdst: 0,        left: null,        right: null    }; // basic statistic, extra statistic    root.bst = UPNG.quantize.stats(nimg, root.i0, root.i1);    root.est = UPNG.quantize.estats(root.bst);    var leafs = [root];    while (leafs.length < ps) {        var maxL = 0,            mi = 0;        for (var i = 0; i < leafs.length; i++)            if (leafs[i].est.L > maxL) {                maxL = leafs[i].est.L;                mi = i;            }        if (maxL < err) break;        var node = leafs[mi];        var s0 = UPNG.quantize.splitPixels(nimg, nimg32, node.i0, node.i1, node.est.e, node.est.eMq255);        var s0wrong = (node.i0 >= s0 || node.i1 <= s0);        //console.log(maxL, leafs.length, mi);        if (s0wrong) {            node.est.L = 0;            continue;        }        var ln = {            i0: node.i0,            i1: s0,            bst: null,            est: null,            tdst: 0,            left: null,            right: null        };        ln.bst = UPNG.quantize.stats(nimg, ln.i0, ln.i1);        ln.est = UPNG.quantize.estats(ln.bst);        var rn = {            i0: s0,            i1: node.i1,            bst: null,            est: null,            tdst: 0,            left: null,            right: null        };        rn.bst = {            R: [],            m: [],            N: node.bst.N - ln.bst.N        };        for (var i = 0; i < 16; i++) rn.bst.R[i] = node.bst.R[i] - ln.bst.R[i];        for (var i = 0; i < 4; i++) rn.bst.m[i] = node.bst.m[i] - ln.bst.m[i];        rn.est = UPNG.quantize.estats(rn.bst);        node.left = ln;        node.right = rn;        leafs[mi] = ln;        leafs.push(rn);    }    leafs.sort(function (a, b) {        return b.bst.N - a.bst.N;    });    for (var i = 0; i < leafs.length; i++) leafs[i].ind = i;    return [root, leafs];}UPNG.quantize.getNearest = function (nd, r, g, b, a) {    if (nd.left == null) {        nd.tdst = UPNG.quantize.dist(nd.est.q, r, g, b, a);        return nd;    }    var planeDst = UPNG.quantize.planeDst(nd.est, r, g, b, a);    var node0 = nd.left,        node1 = nd.right;    if (planeDst > 0) {        node0 = nd.right;        node1 = nd.left;    }    var ln = UPNG.quantize.getNearest(node0, r, g, b, a);    if (ln.tdst <= planeDst * planeDst) return ln;    var rn = UPNG.quantize.getNearest(node1, r, g, b, a);    return rn.tdst < ln.tdst ? rn : ln;}UPNG.quantize.planeDst = function (est, r, g, b, a) {    var e = est.e;    return e[0] * r + e[1] * g + e[2] * b + e[3] * a - est.eMq;}UPNG.quantize.dist = function (q, r, g, b, a) {    var d0 = r - q[0],        d1 = g - q[1],        d2 = b - q[2],        d3 = a - q[3];    return d0 * d0 + d1 * d1 + d2 * d2 + d3 * d3;}UPNG.quantize.splitPixels = function (nimg, nimg32, i0, i1, e, eMq) {    var vecDot = UPNG.quantize.vecDot;    i1 -= 4;    var shfs = 0;    while (i0 < i1) {        while (vecDot(nimg, i0, e) <= eMq) i0 += 4;        while (vecDot(nimg, i1, e) > eMq) i1 -= 4;        if (i0 >= i1) break;        var t = nimg32[i0 >> 2];        nimg32[i0 >> 2] = nimg32[i1 >> 2];        nimg32[i1 >> 2] = t;        i0 += 4;        i1 -= 4;    }    while (vecDot(nimg, i0, e) > eMq) i0 -= 4;    return i0 + 4;}UPNG.quantize.vecDot = function (nimg, i, e) {    return nimg[i] * e[0] + nimg[i + 1] * e[1] + nimg[i + 2] * e[2] + nimg[i + 3] * e[3];}UPNG.quantize.stats = function (nimg, i0, i1) {    var R = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];    var m = [0, 0, 0, 0];    var N = (i1 - i0) >> 2;    for (var i = i0; i < i1; i += 4) {        var r = nimg[i] * (1 / 255),            g = nimg[i + 1] * (1 / 255),            b = nimg[i + 2] * (1 / 255),            a = nimg[i + 3] * (1 / 255);        //var r = nimg[i], g = nimg[i+1], b = nimg[i+2], a = nimg[i+3];        m[0] += r;        m[1] += g;        m[2] += b;        m[3] += a;        R[0] += r * r;        R[1] += r * g;        R[2] += r * b;        R[3] += r * a;        R[5] += g * g;        R[6] += g * b;        R[7] += g * a;        R[10] += b * b;        R[11] += b * a;        R[15] += a * a;    }    R[4] = R[1];    R[8] = R[2];    R[9] = R[6];    R[12] = R[3];    R[13] = R[7];    R[14] = R[11];    return {        R: R,        m: m,        N: N    };}UPNG.quantize.estats = function (stats) {    var R = stats.R,        m = stats.m,        N = stats.N;    // when all samples are equal, but N is large (millions), the Rj can be non-zero ( 0.0003.... - precission error)    var m0 = m[0],        m1 = m[1],        m2 = m[2],        m3 = m[3],        iN = (N == 0 ? 0 : 1 / N);    var Rj = [        R[0] - m0 * m0 * iN, R[1] - m0 * m1 * iN, R[2] - m0 * m2 * iN, R[3] - m0 * m3 * iN,        R[4] - m1 * m0 * iN, R[5] - m1 * m1 * iN, R[6] - m1 * m2 * iN, R[7] - m1 * m3 * iN,        R[8] - m2 * m0 * iN, R[9] - m2 * m1 * iN, R[10] - m2 * m2 * iN, R[11] - m2 * m3 * iN,        R[12] - m3 * m0 * iN, R[13] - m3 * m1 * iN, R[14] - m3 * m2 * iN, R[15] - m3 * m3 * iN    ];    var A = Rj,        M = UPNG.M4;    var b = [Math.random(), Math.random(), Math.random(), Math.random()],        mi = 0,        tmi = 0;    if (N != 0)        for (var i = 0; i < 16; i++) {            b = M.multVec(A, b);            tmi = Math.sqrt(M.dot(b, b));            b = M.sml(1 / tmi, b);            if (i != 0 && Math.abs(tmi - mi) < 1e-9) break;            mi = tmi;        }    //b = [0,0,1,0];  mi=N;    var q = [m0 * iN, m1 * iN, m2 * iN, m3 * iN];    var eMq255 = M.dot(M.sml(255, q), b);    return {        Cov: Rj,        q: q,        e: b,        L: mi,        eMq255: eMq255,        eMq: M.dot(b, q),        rgba: (((Math.round(255 * q[3]) << 24) | (Math.round(255 * q[2]) << 16) | (Math.round(255 * q[1]) << 8) | (Math.round(255 * q[0]) << 0)) >>> 0)    };}UPNG.M4 = {    multVec: function (m, v) {        return [            m[0] * v[0] + m[1] * v[1] + m[2] * v[2] + m[3] * v[3],            m[4] * v[0] + m[5] * v[1] + m[6] * v[2] + m[7] * v[3],            m[8] * v[0] + m[9] * v[1] + m[10] * v[2] + m[11] * v[3],            m[12] * v[0] + m[13] * v[1] + m[14] * v[2] + m[15] * v[3]        ];    },    dot: function (x, y) {        return x[0] * y[0] + x[1] * y[1] + x[2] * y[2] + x[3] * y[3];    },    sml: function (a, y) {        return [a * y[0], a * y[1], a * y[2], a * y[3]];    }}UPNG.encode.concatRGBA = function (bufs) {    var tlen = 0;    for (var i = 0; i < bufs.length; i++) tlen += bufs[i].byteLength;    var nimg = new Uint8Array(tlen),        noff = 0;    for (var i = 0; i < bufs.length; i++) {        var img = new Uint8Array(bufs[i]),            il = img.length;        for (var j = 0; j < il; j += 4) {            var r = img[j],                g = img[j + 1],                b = img[j + 2],                a = img[j + 3];            if (a == 0) r = g = b = 0;            nimg[noff + j] = r;            nimg[noff + j + 1] = g;            nimg[noff + j + 2] = b;            nimg[noff + j + 3] = a;        }        noff += il;    }    return nimg.buffer;}UPNG.encode.dither = function (sb, w, h, plte, tb, oind) {    function addErr(er, tg, ti, f) {        tg[ti] += (er[0] * f) >> 4;        tg[ti + 1] += (er[1] * f) >> 4;        tg[ti + 2] += (er[2] * f) >> 4;        tg[ti + 3] += (er[3] * f) >> 4;    }    function N(x) {        return Math.max(0, Math.min(255, x));    }    function D(a, b) {        var dr = a[0] - b[0],            dg = a[1] - b[1],            db = a[2] - b[2],            da = a[3] - b[3];        return (dr * dr + dg * dg + db * db + da * da);    }    var pc = plte.length,        nplt = [],        rads = [];    for (var i = 0; i < pc; i++) {        var c = plte[i];        nplt.push([((c >>> 0) & 255), ((c >>> 8) & 255), ((c >>> 16) & 255), ((c >>> 24) & 255)]);    }    for (var i = 0; i < pc; i++) {        var ne = 0xffffffff,            ni = 0;        for (var j = 0; j < pc; j++) {            var ce = D(nplt[i], nplt[j]);            if (j != i && ce < ne) {                ne = ce;                ni = j;            }        }        var hd = Math.sqrt(ne) / 2;        rads[i] = ~~(hd * hd);    }    var tb32 = new Uint32Array(tb.buffer);    var err = new Int16Array(w * h * 4);    for (var y = 0; y < h; y++) {        for (var x = 0; x < w; x++) {            var i = (y * w + x) * 4;            var cc = [N(sb[i] + err[i]), N(sb[i + 1] + err[i + 1]), N(sb[i + 2] + err[i + 2]), N(sb[i + 3] + err[i + 3])];            var ni = 0,                nd = 0xffffff;            for (var j = 0; j < pc; j++) {                var cd = D(cc, nplt[j]);                if (cd < nd) {                    nd = cd;                    ni = j;                }            }            //ni = oind[i>>2];            var nc = nplt[ni];            var er = [cc[0] - nc[0], cc[1] - nc[1], cc[2] - nc[2], cc[3] - nc[3]];            //addErr(er, err, i+4, 16);            //*            if (x != w - 1) addErr(er, err, i + 4, 7);            if (y != h - 1) {                if (x != 0) addErr(er, err, i + 4 * w - 4, 3);                addErr(er, err, i + 4 * w, 5);                if (x != w - 1) addErr(er, err, i + 4 * w + 4, 1); //*/            }            oind[i >> 2] = ni;            tb32[i >> 2] = plte[ni];        }    }}module.exports = UPNG
再将png数据转化为Base64数据,所使用的工具包Base64Util:
 export default { arrayBufferToBase64(buffer) {var binary = '';var bytes = new Uint8Array(buffer);var len = bytes.byteLength;for (var i = 0; i < len; i++) {binary += String.fromCharCode(bytes[i]);}var btoa = function(string) {var b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="    string = String(string);    var bitmap, a, b, c,        result = "", i = 0,        rest = string.length % 3; // To determine the final padding    for (; i < string.length;) {        if ((a = string.charCodeAt(i++)) > 255                || (b = string.charCodeAt(i++)) > 255                || (c = string.charCodeAt(i++)) > 255)            throw new TypeError("Failed to execute 'btoa' on 'Window': The string to be encoded contains characters outside of the Latin1 range.");        bitmap = (a << 16) | (b << 8) | c;        result += b64.charAt(bitmap >> 18 & 63) + b64.charAt(bitmap >> 12 & 63)                + b64.charAt(bitmap >> 6 & 63) + b64.charAt(bitmap & 63);    }    // If there's need of padding, replace the last 'A's with equal signs    return rest ? result.slice(0, rest - 3) + "===".substring(rest) : result;}return "data:image/png;base64," + btoa(binary);}}

4.2 控制帧数据采集频率

特别注意:对于微信的这个数据帧采集接口onCameraFrame,它是处于一个以60ms采集一次用户的数据的频率运行的,很多时候我们用不到这么高的频率!我们可以通过setInteerval定时器来控制摄像头采集用户数据的频率。
let task = setInterval(function() {var timeStart = Date.now();//在此处处理store[0](图像的数据);// store.shift();var frame = that.frameQueue.shift()console.log("开始运行===",frame,that.flag);that.flag = true;if(frame != undefined){let pngData = UPNG.encode([frame.data], frame.width, frame.height),  base64 = Base64Util.arrayBufferToBase64(pngData)uni.request({url: 'http://127.0.0.1:8000/miniapp/faceEngine/faceLogin' ,method: 'post',data: {openId:uni.getStorageSync("openId"),base64Img:base64} ,dataType:'json',header: {   'content-type':'application/json'//自定义请求头信息},success:(res)=>{console.log("====执行成功===",res)if(res.statusCode != undefined){clearInterval(task)that.isAuthCamera = falseuni.navigateTo({url:'./login'})}},fail:(err)=>{console.log("====执行失败===",err)clearInterval(task)that.isAuthCamera = falseuni.navigateTo({url:'./login'})}})}

五、实时人脸采集功能实现

在这里插入图片描述


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