【svg+vml】部分尝试
半年前看过国外一个大牛的一个demo，然后自己用他的思路写了一个类似的东西。加了点额外的功能。
当时主要是为了学习svg的部分api，做着玩。
里面有做svg和vml的兼容，所以ie6.0+也ok的，但是效率还是很慢。（画直线，折线，和椭圆）
右上角控制栏里的 “shake”和各种参数都可以点下试试看。
/* ========== for svg and vml compatible ========== */
var __SVG = false;
var __svgNS = false;
if (document.createElementNS) {
__svgNS = "http://www.w3.org/2000/svg";
__svg = document.createElementNS(__svgNS, "svg");
__SVG = (__svg.x != null);
}
if (__SVG) {
/* ============= SVG ============== */
vectorGraphics = function(o, antialias) {
this.canvas = document.createElementNS(__svgNS, "svg");
this.canvas.style.position = "absolute";
o.appendChild(this.canvas);
this.createLine = function(w, col, linecap) {
var o = document.createElementNS(__svgNS, "line");
o.setAttribute("shape-rendering", antialias?"auto":"optimizeSpeed");
o.setAttribute("stroke-width", Math.round(w)+"px");
if (col) o.setAttribute("stroke", col);
if (linecap) o.setAttribute("stroke-linecap", linecap);
o.move = function(x1, y1, x2, y2) {
this.setAttribute("x1", Math.round(x1) + .5);
this.setAttribute("y1", Math.round(y1));
this.setAttribute("x2", Math.round(x2));
this.setAttribute("y2", Math.round(y2));
}
o.color = function(c){ this.setAttribute("stroke", c); }
o.RGBcolor = function(R, G, B){ this.setAttribute("stroke", "rgb("+Math.round(R)+","+Math.round(G)+","+Math.round(B)+")"); }
o.stroke_weight = function(s){ this.setAttribute("stroke-width", Math.round(s)+"px"); }
this.canvas.appendChild(o);
return o;
}
this.createPolyline = function(w, points, col, fill) {
var o = document.createElementNS(__svgNS, "polyline");
o.setAttribute("shape-rendering", antialias?"auto":"optimizeSpeed");
o.setAttribute("stroke-width", Math.round(w));
if (col) o.setAttribute("stroke", col);
o.setAttribute("fill", fill?fill:"none");
if (points) o.setAttribute("points", points);
o.move = function(points) {
this.setAttribute("points", points);
}
this.canvas.appendChild(o);
return o;
}
this.createOval = function(diam, filled) {
var o = document.createElementNS(__svgNS, "circle");
o.setAttribute("shape-rendering", antialias?"auto":"optimizeSpeed");
o.setAttribute("stroke-width", 0);
o.setAttribute("r", Math.round(diam / 2));
o.style.cursor = "pointer";
o.move = function(x1, y1, radius) {
this.setAttribute("cx", Math.round(x1));
this.setAttribute("cy", Math.round(y1));
this.setAttribute("r", Math.round(radius));
}
o.stroke_color = function(col) { this.setAttribute("stroke", col); }
o.fill_color = function(col) { this.setAttribute("fill", col); }
o.stroke_weight = function(sw) { this.setAttribute("stroke-width", sw); }
this.canvas.appendChild(o);
return o;
}
}
} else if (document.createStyleSheet) {
/* ============= VML ============== */
vectorGraphics = function(o, antialias) {
document.namespaces.add("v", "urn:schemas-microsoft-com:vml");
var style = document.createStyleSheet();
var VMLel = ['line','stroke','polyline','fill','oval'];
for (var i=0,l=VMLel.length;i<l;i++) {
style.addRule('v\\:'+VMLel[i], "behavior: url(#default#VML);");
style.addRule('v\\:'+VMLel[i], "antialias: "+antialias+";");
}
this.canvas = o;
this.createLine = function(w, col, linecap) {
var o = document.createElement("v:line");
o.strokeweight = Math.round(w)+"px";
if (col) o.strokecolor = col;
o.move = function(x1, y1, x2, y2) {
this.to = (Math.round(x1) + .5) + "," + Math.round(y1);
this.from = Math.round(x2) + "," + Math.round(y2);
}
o.color = function(c){ this.strokecolor = c; }
o.RGBcolor = function(R, G, B){ this.strokecolor = "rgb("+Math.round(R)+","+Math.round(G)+","+Math.round(B)+")"; }
o.stroke_weight = function(s){ this.strokeweight = Math.round(s)+"px"; }
if (linecap) {
s = document.createElement("v:stroke");
s.endcap = linecap;
o.appendChild(s);
}
this.canvas.appendChild(o);
return o;
}
this.createPolyline = function(w, points, col, fill) {
var o = document.createElement("v:polyline");
o.strokeweight = Math.round(w)+"px";
if (col) o.strokecolor = col;
o.points = points;
if (fill) o.fillcolor = fill;
else {
s = document.createElement("v:fill");
s.on = "false";
o.appendChild(s);
}
o.move = function(points) {
this.points.value = points;
}
this.canvas.appendChild(o);
return o;
}
this.createOval = function(diam, filled) {
var o = document.createElement("v:oval");
var os = o.style;
os.position = "absolute";
os.cursor = "pointer";
o.strokeweight = 1;
o.filled = filled;
os.width = Math.round(diam) + "px";
os.height = Math.round(diam) + "px";
o.move = function(x1, y1, radius) {
os.left = Math.round(x1 - radius) + "px";
os.top = Math.round(y1 - radius) + "px";
os.width = Math.round(radius * 2) + "px";
os.height = Math.round(radius * 2) + "px";
}
o.stroke_color = function(col) { this.strokecolor = col; }
o.fill_color = function(col) { this.fillcolor = col; }
o.stroke_weight = function(sw) { this.strokeweight = sw; }
this.canvas.appendChild(o);
return o;
}
}
} else {
/* ==== no script ==== */
vectorGraphics = function(o, i) {
return false;
}
}
在做浏览器适配的时候，某些情况下不得不考虑ie低版本的兼容时，其实svg+vml在矢量图方面算个不错的选择。
利用上面的直线和圆，其实就可以做个时钟了。: )
