用TWaver HTML5定制五彩斑斓的链路

最近有客户提到自定义链路的需求，个人感觉非常有代表意义，现在共享出来给大家参考一下。先来看看需求：

1. 链路要分成两半，用两种颜色填充。
2. 填充百分比在不同值域时，用不同颜色。
3. 显示刻度

   

4. 有个开关，可以控制链路变短，变短后，链路只画开始和结束部分（相当于原始链路的缩影），中间不画

   

5. 如果有多条链路，链路合并后两端分别显示这些链路中的最高填充百分比

   合并前：
   
   合并后：
   

6. 进入子网后，节点上显示和上层节点的连线信息

进入子网前，节点2和子网内节点4之间有链路：

进入子网后，节点4上也显示此链路：

先看看实现的效果，后面我们慢慢解释如何定制链路：

前5个需求可以通过自定义Link和LinkUI实现，需要注意：

1. 用Link#getBundleLinks获取所有的捆绑链路
2. 用LinkUI#drawLinePoints画线

完整代码如下：

// 自定义Link构造函数
demo.ScaleLink = function(id, from, to) {
    // 调用基类构造函数
    demo.ScaleLink.superClass.constructor.call(this, id, from, to);
    // 设置链路宽度为10个像素
    this.setStyle('link.width', 10);
    //this.setStyle('link.color', 'rgba(0, 0, 0, 0)');
    // 设置Link类型为平行
    this.setStyle('link.type', 'parallel');
    // 设置链路捆绑的间距为40
    this.setStyle('link.bundle.offset', 40);
    // 设置刻度颜色
    this.setClient('scaleColor', 'black');
    // 设置刻度宽度
    this.setClient('scaleWidth', 1);
    // 设置刻度个数
    this.setClient('scaleNumbers', 4);
    // 设置是否变短
    this.setClient('shortened', false);
    // 设置变短后的长度
    this.setClient('shortenLength', 100);
    // 设置分割线颜色
    this.setClient('splitterColor', 'black');
    // 设置起始填充百分比
    this.setClient('fromFillPercent', 0);
    // 设置结束填充百分比
    this.setClient('toFillPercent', 0);
};
// 设置自定义Link继承twaver.Link
twaver.Util.ext('demo.ScaleLink', twaver.Link, {
    // 重载获取UI类方法，返回自定义UI类
	getCanvasUIClass : function () {
		return demo.ScaleLinkUI;
	},
	// 根据百分比获取填充颜色
	getFillColor: function(percent) {
		if (percent < 0.25) {
			return 'green';
		}
		if (percent < 0.5) {
			return 'yellow';
		}
		if (percent < 0.75) {
			return 'magenta';
		}
		return 'red';
	},
	// 获取起始填充颜色
	getFromFillColor: function () {
		return this.getFillColor(this.getFromFillPercent());
	},
	// 获取结束填充颜色
	getToFillColor: function () {
		return this.getFillColor(this.getToFillPercent());
	},
	// 获取起始百分比
	getFromFillPercent: function () {
	    // 如果是链路捆绑代理，返回所有捆绑链路中填充百分比最大的值
		if (this.isBundleAgent()) {
			var fromAgent = this.getFromAgent(),
				percentKey, maxPercent = 0, percent;
			this.getBundleLinks().forEachSiblingLink(function (link) {
				percentKey = fromAgent === link.getFromAgent() ? 'fromFillPercent' : 'toFillPercent';
				percent = link.getClient(percentKey);
				maxPercent = percent > maxPercent ? percent : maxPercent;
			});
			return maxPercent;
		} else {
			return this.getClient('fromFillPercent');
		}
	},
	// 获取结束百分比
	getToFillPercent: function () {
	    // 如果是链路捆绑代理，返回所有捆绑链路中填充百分比最大的值
		if (this.isBundleAgent()) {
			var toAgent = this.getToAgent(),
				percentKey, maxPercent = 0, percent;
			this.getBundleLinks().forEachSiblingLink(function (link) {
				percentKey = toAgent === link.getToAgent() ? 'toFillPercent' : 'fromFillPercent';
				percent = link.getClient(percentKey);
				maxPercent = percent > maxPercent ? percent : maxPercent;
			});
			return maxPercent;
		} else {
			return this.getClient('toFillPercent');
		}
	},
	// 重载获取网元名称方法，判断如果是链路捆绑代理，就返回起始和结束代理节点的名称
	getName: function () {
	    if (this.getClient('shortened')) {
	        return null;
	    } else if (this.isBundleAgent()) {
			return this.getFromAgent().getName() + '-' + this.getToAgent().getName();
		} else {
			return demo.ScaleLink.superClass.getName.call(this);
		}
	}
});

// 自定义LinkUI构造函数
demo.ScaleLinkUI = function(network, element){
    // 调用基类构造函数
    demo.ScaleLinkUI.superClass.constructor.call(this, network, element);
};
// 设置自定义Link继承twaver.canvas.LinkUI
twaver.Util.ext('demo.ScaleLinkUI', twaver.canvas.LinkUI, {
	// 获取Link角度
	getAngle: function () {
		return getAngle(this.getFromPoint(), this.getToPoint());
	},
	// 获取Link中间点
	getMiddlePoint: function (from, to, percent) {
		return {
	    	x: from.x + (to.x - from.x) * percent,
	    	y: from.y + (to.y - from.y) * percent
	    };
	},
	// 画刻度线
	drawScaleLine: function (from, to, angle, length, ctx, percent, lineWidth, lineColor) {
	    var point = this.getMiddlePoint(from, to, percent);
	    var y = length/2 * Math.sin(angle),
	    	x = length/2 * Math.cos(angle);
	    ctx.beginPath();
	    ctx.lineWidth = lineWidth;
	    ctx.strokeStyle = lineColor;
	    ctx.moveTo(point.x + x, point.y + y);
	    ctx.lineTo(point.x - x, point.y -y);
	    ctx.stroke();
	},
	// 获取是否将链路变短
	isShorten: function () {
		var link = this.getElement();
		return link.getClient('shortened') && this.getLineLength() > link.getClient('shortenLength') * 2;
	},
	// 重载画链路函数，用自定义逻辑画链路
	paintBody: function (ctx) {
        var points = this.getLinkPoints(),
        	link = this.getElement();
        if (!points || points.size() < 2) {
            return;
        }

        var lineLength = this.getLineLength(),
        	shortenLength = link.getClient('shortenLength'),
        	percent = shortenLength / lineLength,
	    	from = points.get(0),
	    	to = points.get(1),
	    	angle = this.getAngle() + Math.PI/2;
	    if (this.isShorten()) {
        	fromPoints = new twaver.List([from, this.getMiddlePoint(from, to, percent)]);
        	toPoints = new twaver.List([this.getMiddlePoint(from, to, 1 - percent), to]);
        	this._paintBody(ctx, fromPoints, angle);
        	this._paintBody(ctx, toPoints, angle);

        	// 画文字
			ctx.textAlign = 'center';
			ctx.textBaseline = 'middle';
			ctx.fillStyle = 'black';
			var textCenter = {x: (fromPoints.get(0).x + fromPoints.get(1).x)/2, y: (fromPoints.get(0).y + fromPoints.get(1).y)/2};
			ctx.fillText(link.getName(), textCenter.x, textCenter.y);

			textCenter = {x: (toPoints.get(0).x + toPoints.get(1).x)/2, y: (toPoints.get(0).y + toPoints.get(1).y)/2};
			ctx.fillText(link.getName(), textCenter.x, textCenter.y);

			ctx.fillText(link.getToNode().getName(), fromPoints.get(1).x, fromPoints.get(1).y);
			ctx.fillText(link.getFromNode().getName(), toPoints.get(0).x, toPoints.get(0).y);
        } else {
        	this._paintBody(ctx, points, angle);
        }

		// 画起始箭头
		if (link.getClient('arrow.from')) {
		    twaver.Util.drawArrow(ctx, 12, 9, points, true, 'arrow.standard', true, 'gray', 0, 0, 1, 'black');
        }
	    // 画结束箭头
        if (link.getClient('arrow.to')) {
		    twaver.Util.drawArrow(ctx, 12, 9, points, false, 'arrow.standard', true, 'gray', 0, 0, 1, 'black');
        }
	},
	_paintBody: function (ctx, points, angle) {
        var link = this.getElement(),
        	width = link.getStyle('link.width'),
        	grow = width,
        	outerColor = this.getOuterColor();
        if (outerColor) {
            var outerWidth = link.getStyle('outer.width');
            grow += outerWidth * 2;
        }
        var selectBorder = !this.getEditAttachment() && link.getStyle('select.style') === 'border' && this.getNetwork().isSelected(link);
        if (selectBorder) {
            var selectWidth = link.getStyle('select.width');
            grow += selectWidth * 2;
        }
        ctx.lineCap = link.getStyle('link.cap');
        ctx.lineJoin = link.getStyle('link.join');
        // 画选中边框
        if (selectBorder) {
            this.drawLinePoints(ctx, points, grow, link.getStyle('select.color'));
        }
        // 画边框
        if (outerColor) {
            this.drawLinePoints(ctx, points, width + outerWidth * 2, outerColor);
        }
        // 画Link
        this.drawLinePoints(ctx, points, width, this.getInnerColor() || link.getStyle('link.color'));

		var fromFillPercent = link.getFromFillPercent(),
	    	toFillPercent = link.getToFillPercent(),
	    	fromFillColor = link.getFromFillColor(),
	    	toFillColor = link.getToFillColor(),
	    	from = points.get(0),
	    	to = points.get(1);

	    var x = from.x + (to.x - from.x) / 2 * fromFillPercent,
	    	y = from.y + (to.y - from.y) / 2 * fromFillPercent;
	    var middle = {x: x, y: y};
	    var fromPoints = new twaver.List([from, middle]);
		// 画起始填充色
	    this.drawLinePoints(ctx, fromPoints, width, fromFillColor);

	    from = points.get(1);
	    to = points.get(0);
	    x = from.x + (to.x - from.x) / 2 * toFillPercent;
	    y = from.y + (to.y - from.y) / 2 * toFillPercent;
	    middle = {x: x, y: y};
	    var toPoints = new twaver.List([from, middle]);
	    // 画结束填充色
	    this.drawLinePoints(ctx, toPoints, width, toFillColor);

    	from = points.get(0);
    	to = points.get(1);
	    var scaleWidth = link.getClient('scaleWidth'),
	    	scaleColor = link.getClient('scaleColor');
	    // 画刻度
	    for (var i = 1, n = link.getClient('scaleNumbers') * 2; i < n; i++) {
	    	this.drawScaleLine(from, to, angle, width/2, ctx, i/n, scaleWidth, scaleColor);
	    }
	    // 画分隔线
	    this.drawScaleLine(from, to, angle, width, ctx, 0.5, 3, link.getClient('splitterColor'));
	}
});

最后一个需求可以通过定制Node和NodeUI达到目的：

// 自定义Node构造函数
demo.ScaleNode = function(id) {
    // 调用基类构造函数
	demo.ScaleNode.superClass.constructor.call(this, id);
};
// 设置自定义Node继承twaver.Node
twaver.Util.ext('demo.ScaleNode', twaver.Node, {
	getCanvasUIClass: function () {
		return demo.ScaleNodeUI;
	}
});

// 自定义NodeUI构造函数
demo.ScaleNodeUI = function(network, element){
    // 调用基类构造函数
    demo.ScaleNodeUI.superClass.constructor.call(this, network, element);
};
// 设置自定义NodeUI继承twaver.canvas.NodeUI
twaver.Util.ext('demo.ScaleNodeUI', twaver.canvas.NodeUI, {
    // 重载画网元方法，画上层链路
	paintBody: function (ctx) {
		demo.ScaleNodeUI.superClass.paintBody.call(this, ctx);
    	var result = this.getAttachedLinks();
    	if (!result) {
    		return;
    	}
    	for (var position in result) {
    		this.paintLink(ctx, result[position], position);
    	}
	},
    // 画链路
    paintLink: function (ctx, links, position) {
    	var center = this.getElement().getCenterLocation(),
    		count = links.length,
    		half = count / 2,
    		network = this.getNetwork(),
    		gap = (count - 1) * -10,
    		terminal, link, i, offset, shortenLength, angle, tempCenter, textWidth, textHeight = 20, textCenter;
    	for (i=0; i<count; i++) {
    		link = links[i];
    		offset = link.getStyle('link.bundle.offset');
    		shortenLength = link.getClient('shortenLength');
    		textWidth = ctx.measureText(link.getName()).width;
	    	if (position === 'left') {
	    		terminal = {x: center.x - offset - shortenLength, y: center.y + gap};
	    		tempCenter = {x: center.x - offset, y: center.y + gap};
	    		textCenter = {x: terminal.x - textWidth/2 - 10, y: terminal.y};
	    		angle = Math.PI/2;
	    	} else if (position === 'right') {
	    		terminal = {x: center.x + offset + shortenLength, y: center.y + gap};
	    		tempCenter = {x: center.x + offset, y: center.y + gap};
	    		textCenter = {x: terminal.x + textWidth/2 + 10, y: terminal.y};
	    		angle = Math.PI/2;
	    	} else if (position === 'top') {
	    		terminal = {x: center.x + gap, y: center.y - offset - shortenLength};
	    		tempCenter = {x: center.x + gap, y: center.y - offset};
	    		textCenter = {x: terminal.x, y: terminal.y - 10};
	    		angle = 0;
	    	} else {
	    		terminal = {x: center.x + gap, y: center.y + offset + shortenLength};
	    		tempCenter = {x: center.x + gap, y: center.y + offset};
	    		textCenter = {x: terminal.x, y: terminal.y + 10};
	    		angle = 0;
	    	}
	    	gap += 20;
	    	var isFrom = link.getFromNode() === this.getElement(),
	    		points;
	    	if (isFrom) {
	    		points = new twaver.List([tempCenter, terminal]);
	    	} else {
	    		points = new twaver.List([terminal, tempCenter]);
	    	}
	    	network.getElementUI(link)._paintBody(ctx, points, angle);

			ctx.textAlign = 'center';
			ctx.textBaseline = 'middle';
			ctx.fillStyle = 'black';
			// 另一端节点标签
			var name = isFrom ? link.getToNode().getName() : link.getFromNode().getName();
			ctx.fillText(name, textCenter.x, textCenter.y);
			textCenter = {x: (tempCenter.x + terminal.x)/2, y: (tempCenter.y + terminal.y)/2};
			// Link标签
			ctx.fillText(link.getName(), textCenter.x, textCenter.y);

			// 画起始箭头
			if (link.getClient('arrow.from')) {
			    twaver.Util.drawArrow(ctx, 12, 9, points, true, 'arrow.standard', true, 'gray', 0, 0, 1, 'black');
            }
		    // 画结束箭头
            if (link.getClient('arrow.to')) {
			    twaver.Util.drawArrow(ctx, 12, 9, points, false, 'arrow.standard', true, 'gray', 0, 0, 1, 'black');
            }
	    }
    },
    // 获取不同方位的上层链路集合
	getAttachedLinks: function () {
		var currentSubNetwork = this.getNetwork().getCurrentSubNetwork();
		if (!currentSubNetwork || !this.getElement().getLinks()) {
			return null;
		}
		var result;
		this.getElement().getLinks().forEach(function (link) {
			var fromSubNetwork = twaver.Util.getSubNetwork(link.getFromNode()),
				toSubNetwork = twaver.Util.getSubNetwork(link.getToNode());
			if (fromSubNetwork !== toSubNetwork) {
				if (!result) {
					result = {};
				}
				var fromCenter = link.getFromNode().getCenterLocation(),
					toCenter = link.getToNode().getCenterLocation(),
					angle = getAngle(fromCenter, toCenter),
					isOut = currentSubNetwork === fromSubNetwork,
					position;
				if (isOut) {
					if (fromCenter.x <= toCenter.x) {
						if (angle >= -Math.PI/4 && angle <= Math.PI/4) {
							position = 'right';
						} else if (angle > Math.PI/4) {
							position = 'bottom';
						} else {
							position = 'top';
						}
					} else {
						if (angle >= -Math.PI/4 && angle <= Math.PI/4) {
							position = 'left';
						} else if (angle > Math.PI/4) {
							position = 'top';
						} else {
							position = 'bottom';
						}
					}
				} else {
					if (fromCenter.x <= toCenter.x) {
						if (angle >= -Math.PI/4 && angle <= Math.PI/4) {
							position = 'left';
						} else if (angle > Math.PI/4) {
							position = 'top';
						} else {
							position = 'bottom';
						}
					} else {
						if (angle >= -Math.PI/4 && angle <= Math.PI/4) {
							position = 'right';
						} else if (angle > Math.PI/4) {
							position = 'bottom';
						} else {
							position = 'top';
						}
					}
				}
				if (!result[position]) {
					result[position] = [];
				}
				result[position].push(link);
			}
		});
		return result;
	}
});

本文完整代码见附件：见原文左下方