解析鉆孔(Excellon)格式前首先得了解此格式，這樣才能更好的解析呀。

一個鉆孔裏面包含的基本信息如下：

1.單位：公式mm,英制inch

2.省零方式：前省零,後省零

3.坐標方式：絕對坐標，相對坐標

4.坐標位數：3:3，2:4

5.鉆孔刀徑信息

6.鉆孔坐標信息

更多EXCELLON格式詳見

https://wenku.baidu.com/view/4e9553b765ce0508763213e9.html

一.數據結構信息

此結構僅用於解析Excellon格式繪出鉆孔圖形,

後續改進點：

1.需增加G84,G85 擴孔;槽孔

2.需增加支持絕對坐標，

3.若要擴展用戶交互功能，需改進此結構，鉆孔目前是統一在一個集合中的，需改為按刀具大小分類存儲

4.鉆孔格式固定幾類格式3:3,2:4，無法智能匹配鉆孔格式,需改為依據板板尺寸或線路焊盤與鉆孔格式多次匹配最佳鉆孔格式

5.此為解析是基於常規鉆孔格式解析，特殊鉆孔格式是不支持的.所以此點需改進.

二.JS代碼實現：

function loadDrill(text) {
    text = text.replace(/^[\s%]*M48/, ‘‘);
    text = text.replace(/[^\S\n]+/g, ‘‘);
    
    function
 
 numVal(x) {
        if(x[0] == ‘+‘)
            return numVal(x.slice(1));
        if(x[0] == ‘-‘)
            return -numVal(x.slice(1));
        if(x == ‘0‘)
            return 0;
        if(g.omitLead)
            while(x.length < g.num)
                x = ‘0‘+x;
        else
            while(x.length < g.num)
                x 
 
+= ‘0‘;
        return parseFloat(x.slice(0, g.int)+‘.‘+x.slice(g.int), 10);
    }
    
    var cmds = text.split(‘\n‘);
    
    var g = {offA: 0, offB: 0, shapes: [], cmds: [], scale: 1}, shape, body = false, prevX = 0, prevY = 0;
    
    for(var i = 0; i < cmds.length; i++) {
        var d = cmds[i];
        if(!body) {
            if(d[0] == ‘T‘) {
                var r = /^T(\d+)[^C]*C([\d.]+)/.exec(d); // assert(r);
                g.shapes[parseInt(r[1], 10)] = [‘C‘, +r[2]];
            }
            else if(d == ‘METRIC,LZ‘)
                g.scale = 1, g.omitLead = false, g.int = 3, g.dec = 3, g.num = 6;
            else if(d == ‘METRIC,TZ‘ || d == ‘M71‘)
                g.scale = 1, g.omitLead = true, g.int = 3, g.dec = 3, g.num = 6;
            else if(d == ‘INCH,LZ‘)
                g.scale = 25.4, g.omitLead = false, g.int = 2, g.dec = 4, g.num = 6;
            else if(d == ‘INCH,TZ‘ || d == ‘M72‘)
                g.scale = 25.4, g.omitLead = true, g.int = 2, g.dec = 4, g.num = 6;
            else if(d == ‘%‘)
                body = true;
        } else {
            function getNum(offset) {
                var r = /^[-+\d]*/.exec(d = d.slice(offset)); // assert(r);
                d = d.slice(r[0].length);
                return numVal(r[0]);
            }
            if(d[0] == ‘T‘)
                shape = parseInt(d.slice(1), 10);
            else if(d[0] == ‘R‘) {
                var r = /^\d+/.exec(d = d.slice(1)); // assert(r);
                var nr = parseInt(r[0], 10), dx = 0, dy = 0;
                d = d.slice(r[0].length);
                if(d[0] == ‘X‘)
                    dx = getNum(1);
                if(d[0] == ‘Y‘)
                    dy = getNum(1);
                
                // assert(!d.length);
                for(var x = prevX, y = prevY, j = 0; j < nr; j++)
                    x += dx, y += dy, g.cmds.push([(1<<2) | 3, shape, x, y]);
                prevX = x, prevY = y;
            }
            else {
                var x = prevX, y = prevY, coords = false;
                if(d[0] == ‘X‘)
                    x = getNum(1), coords = true;
                if(d[0] == ‘Y‘)
                    y = getNum(1), coords = true;
                if(coords) {
                    g.cmds.push([(1<<2) | 3, shape, x, y]);
                    prevX = x, prevY = y;
                }
            }
        }
    }
    return g;
};

三.鉆孔解析繪圖Web效果圖

JS解析展示，無交互功能，雖然是在前端,但最佳作法解析動作放在後端，後端解析後的數據或圖像傳送到前端

PCB javascript解析鉆孔(Excellon)格式說明