.draw-line{
font-size:1px;
}
var Line = function() {
var color = "#808080";
var pointArray = [];
var idocument = document;
var draw = {
// 画出最基本的图像，点，和垂直直线或水平直线
drawBase : function(x1, y1, w, h) {
try {
var span = idocument.createElement("span");
span.style.position = 'absolute';
span.style.left = x1;
span.style.top = y1;
span.style.height = h;
span.style.width = w;
span.style.background = color;
span.className = 'draw-line';
idocument.body.appendChild(span);
pointArray.push(span);
} catch (e) {
}
},
drawLine : function(x1, y1, x2, y2) {
var w = (((x2 - x1) == 0 ? 1 : (x2 - x1)));
var h = (((y2 - y1) == 0 ? 1 : (y2 - y1)));
if (x1 == x2 || y1 == y2) {
// 水平或垂直
var minX = (x1 < x2 ? x1 : x2);
var minY = (y1 < y2 ? y1 : y2);
draw.drawBase(minX, minY, Math.abs(w), Math.abs(h));
} else {// 斜线
var oldX = -1;
var oldY = -1;
var newX = 0;
var newY = 0;
if (Math.abs(w) > Math.abs(h)) {
for (var i = 0; i < Math.abs(w); i++) {
newX = (x1 + (w > 0 ? 1 : -1) * i);
newY = (y1 + (h > 0 ? 1 : -1) * Math.abs(i * h / w));
if (oldX != newX && oldY != newY) {
oldX = newX;
oldY = newY;
draw.drawBase(oldX, oldY, 1, 1)
}
}
} else {
for (var i = 0; i < Math.abs(h); i++) {
newX = (x1 + (w > 0 ? 1 : -1) * Math.abs(i * w / h));
newY = (y1 + (h > 0 ? 1 : -1) * i);
if (oldX != newX && oldY != newY) {
oldX = newX;
oldY = newY;
draw.drawBase(oldX, oldY, 1, 1)
}
}
}
}
},
drawArrowheaded : function(x0, y0, x1, y1){// 箭头
var w = (((x1 - x0) == 0 ? 1 : (x1 - x0)));
var h = (((y1 - y0) == 0 ? 1 : (y1 - y0)));
var d = Math.sqrt((y1 - y0) * (y1 - y0) + (x1 - x0) * (x1 - x0));
var Xa = x1 + 10 * ((x0 - x1) + (y0 - y1) / 2) / d;
var Ya = y1 + 10 * ((y0 - y1) - (x0 - x1) / 2) / d;
var Xb = x1 + 10 * ((x0 - x1) - (y0 - y1) / 2) / d;
var Yb = y1 + 10 * ((y0 - y1) + (x0 - x1) / 2) / d;
draw.drawLine(x1, y1, Xa, Ya);
draw.drawLine(x1, y1, Xb, Yb);
},
drawArrowheadedLine : function(x1, y1, x2, y2) {
// 直线
draw.drawLine(x1, y1, x2, y2);
// 箭头
draw.drawArrowheaded(x1, y1, x2, y2);
}
}
Line.prototype.drawArrowLine = function(x1, y1, x2, y2) {
draw.drawArrowheadedLine(x1, y1, x2, y2);
}
Line.prototype.remove = function() {// 删除画出的线
var len = pointArray.length;
for (var i = 0; i < len; i++) {
idocument.body.removeChild(pointArray[i]);
}
pointArray = null;
pointArray = [];
}
Line.prototype.setDocument = function(idoc) {
idocument = idoc;
}
Line.prototype.setColor = function(newColor) {// 设置线条颜色
color = newColor;
}
}
var line = new Line();
line.drawArrowLine(10, 10, 1000, 200);