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将图片转化为base64字符串

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API和组件

在这个过程中支持document.createElement()方法吗

最后一次编辑于  2017-12-07
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9 个回答

  • 王,的盛宴。。
    王,的盛宴。。
    2017-12-11

    嗯,我试试


    2017-12-11
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  • 名字刚好七个字
    名字刚好七个字
    2017-12-11

    先建一个js

    (function () {

    var sign = {

    utf8to16: function (str) {

    var out, i, len, c;

    var char2, char3;

    out = "";

    len = str.length;

    i = 0;

    while (i < len) {

    c = str.charCodeAt(i++);

    switch (c >> 4) {

    case 0: case 1: case 2: case 3: case 4: case 5: case 6:

    case 7: {

    out += str.charAt(i - 1); break;

    }

    case 12: case 13: {

    char2 = str.charCodeAt(i++);

    out += String.fromCharCode(((c & 0x1F) << 6) | (char2 & 0x3F));

    break;

    }

    case 14: {

    char2 = str.charCodeAt(i++);

    char3 = str.charCodeAt(i++);

    out += String.fromCharCode(((c & 0x0F) << 12) | ((char2 & 0x3F) << 6) | ((char3 & 0x3F) << 0));

    break;

    }

    }


    }

    return out;

    },

    signencode: function (str) {

    var  signEncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

    var signDecodeChars = new Array(

    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,

    52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,

    -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,

    15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,

    -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,

    41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1);

    var out, i, len;

    var c1, c2, c3;

    len = str.length;

    i = 0;

    out = "";

    while (i < len) {

    c1 = str.charCodeAt(i++) & 0xff;

    if (i == len) {

    out += signEncodeChars.charAt(c1 >> 2);

    out += signEncodeChars.charAt((c1 & 0x3) << 4);

    out += "==";

    break;

    }

    c2 = str.charCodeAt(i++);

    if (i == len) {

    out += signEncodeChars.charAt(c1 >> 2);

    out += signEncodeChars.charAt(((c1 & 0x3) << 4) | ((c2 & 0xF0) >> 4));

    out += signEncodeChars.charAt((c2 & 0xF) << 2);

    out += "=";

    break;

    }

    c3 = str.charCodeAt(i++);

    out += signEncodeChars.charAt(c1 >> 2);

    out += signEncodeChars.charAt(((c1 & 0x3) << 4) | ((c2 & 0xF0) >> 4));

    out += signEncodeChars.charAt(((c2 & 0xF) << 2) | ((c3 & 0xC0) >> 6));

    out += signEncodeChars.charAt(c3 & 0x3F);

    }

    return out.substr(0, out.length - 2);

    },

    signdecode: function (str) {

    var signEncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

    var signDecodeChars = new Array(

    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,

    52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,

    -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,

    15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,

    -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,

    41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1);

    var c1, c2, c3, c4;

    var i, len, out;

    len = str.length;

    i = 0;

    out = "";

    while (i < len) {


    do {


    c1 = signDecodeChars[str.charCodeAt(i++) & 0xff];


    } while (i < len && c1 == -1);


    if (c1 == -1) { break; }


    do {

    c2 = signDecodeChars[str.charCodeAt(i++) & 0xff];

    } while (i < len && c2 == -1);


    if (c2 == -1) { break; }


    out += String.fromCharCode((c1 << 2) | ((c2 & 0x30) >> 4));

    do {


    c3 = str.charCodeAt(i++) & 0xff;


    if (c3 == 61) { return out; }


    c3 =signDecodeChars[c3];


    } while (i < len && c3 == -1);


    if (c3 == -1) { break; }


    out += String.fromCharCode(((c2 & 0XF) << 4) | ((c3 & 0x3C) >> 2));


    do {


    c4 = str.charCodeAt(i++) & 0xff;

    if (c4 == 61) { return out; }

    c4 = signDecodeChars[c4];


    } while (i < len && c4 == -1);


    if (c4 == -1) { break; }


    out += String.fromCharCode(((c3 & 0x03) << 6) | c4);

    }

    return  out

    },

    decode: function (str) {

    var signEncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

    var signDecodeChars = new Array(

    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,

    52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,

    -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,

    15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,

    -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,

    41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1);


    var c1, c2, c3, c4;


    var i, len, out;


    len = str.length;

    i = 0;

    out = "";

    while (i < len) {

    do {

    c1 =signDecodeChars[str.charCodeAt(i++) & 0xff];

    } while (i < len && c1 == -1);

    if (c1 == -1) { break; }

    do {

    c2 =signDecodeChars[str.charCodeAt(i++) & 0xff];

    } while (i < len && c2 == -1);

    if (c2 == -1) { break; }

    out += String.fromCharCode((c1 << 2) | ((c2 & 0x30) >> 4));

    do {


    c3 = str.charCodeAt(i++) & 0xff;


    if (c3 == 61) { return out; }


    c3 =signDecodeChars[c3];


    } while (i < len && c3 == -1);


    if (c3 == -1) { break; }


    out += String.fromCharCode(((c2 & 0XF) << 4) | ((c3 & 0x3C) >> 2));


    do {


    c4 = str.charCodeAt(i++) & 0xff;

    if (c4 == 61) { return out; }

    c4 =signDecodeChars[c4];


    } while (i < len && c4 == -1);


    if (c4 == -1) { break; }


    out += String.fromCharCode(((c3 & 0x03) << 6) | c4);

    }


    return sign.utf8to16(out);

    }

    }

    module.exports = {

    "sign": sign

    }


    })();

    然后require

    然后调用sign.signencode(图片流)  后台直接base解码就可以了



    2017-12-11
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  • 王,的盛宴。。
    王,的盛宴。。
    2017-12-07

    谢谢,知道了

    2017-12-07
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  • 仙森ღ₅₂₀¹³¹⁴
    仙森ღ₅₂₀¹³¹⁴
    2017-12-07

    没有转成base64的。。。。不过你们可以上传拿到的本地图片链接,然后后端生成cdn地址返给你

    2017-12-07
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  • 王,的盛宴。。
    王,的盛宴。。
    2017-12-07

    要上传的,要存到服务器上的啊


    2017-12-07
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  • 王,的盛宴。。
    王,的盛宴。。
    2017-12-07

    那在小程序里可以将图片转成base64的方法吗,可以实现吗


    2017-12-07
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  • 仙森ღ₅₂₀¹³¹⁴
    仙森ღ₅₂₀¹³¹⁴
    2017-12-07

    使用wx.getImageInfo 可以直接拿到本地链接 直接显示在页面上即可  - -都不用上传

    2017-12-07
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  • 王,的盛宴。。
    王,的盛宴。。
    2017-12-07

    转成base64传给后台,你有什么方法吗

    2017-12-07
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  • 仙森ღ₅₂₀¹³¹⁴
    仙森ღ₅₂₀¹³¹⁴
    2017-12-07

    不支持的吧。。为啥要转base64 使用wx.getimageinfo好像是这个 可以拿到图片的本地链接

    2017-12-07
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