canvas手绘雷达图
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let width = 750; // canvas的宽
let height = 750; // canvas的高
let angleNum = 7; // 角数，即多少个数据项 【3，10】
let angleAvg = 360 / angleNum; // 分角度平均值
let angleOffset = 13; // 角度偏移量
let layerNum = 7; // 层数，即环层数量
let layerWidth = 0; // 层宽
let bgLineColor = ‘#ffffff’; // 背景线条颜色
let bgLineWidth = 0; // 背景线条宽度
let centerPoint = [0, 0]; // 中心点坐标
let layerPoints = []; // 各层上的点
let wordColor = ‘#ffffff’; // 字体颜色
let fontSize = 0; // 字体大小
let wordArr = [‘项A’, ‘项B’, ‘项C’, ‘项D’, ‘项E’, ‘项F’, ‘项G’]; // 字体数组
let wordOffset = [[0, 0], [0, 0], [0, 0], [0, 0], [0, 0], [0, 0], [0, 0]];
let circleWidth = 0; // 圆点宽度
// 绘制的雷达比例数据
let dataArr = [5, 2, 6, 2, 6, 0, 3];
let context =null;
let windowWidth = 0;
let radar = {
init: function(data) {
centerPoint = [rpx(375), rpx(375)];
layerWidth = rpx(34);
bgLineWidth = rpx(1.6);
fontSize = rpx(26);
circleWidth = rpx(8);
wordOffset = [
[rpx(-30), rpx(40)],
[rpx(40), rpx(40)],
[rpx(65), rpx(10)],
[rpx(90), rpx(0)],
[rpx(-25), rpx(15)],
[rpx(15), rpx(-5)],
[rpx(10), rpx(15)]
];
},
draw: function(data) {
let n = 0, m = 0, k = 0;
this.init(data);
//画背景线条
context = wx.createContext();
context.setLineWidth(bgLineWidth);
context.setStrokeStyle(bgLineColor);
context.beginPath();
context.setFontSize(fontSize);
context.setFillStyle(wordColor);
for(n = 0; n < layerNum; n++) {
layerPoints[n] = [];
for(k = 0; k < angleNum; k++) {
context.moveTo(centerPoint[0], centerPoint[1]);
let offsetX = layerWidth * (n + 1) * getXParam(angleAvg * (k + 1) + angleOffset);
let offsetY = layerWidth * (n + 1) * getYParam(angleAvg * (k + 1) + angleOffset);
let distX = centerPoint[0] + offsetX;
let distY = centerPoint[1] + offsetY;
if(n == layerNum – 1) {
context.lineTo(distX, distY);
if(wordArr[k]) {
let wordOffsetX = offsetX >= 0 ? 1 : -1;
wordOffsetX = distX + wordOffsetX * wordOffset[k][0];
let wordOffsetY = offsetY >= 0 ? 1 : -1;
wordOffsetY = distY + wordOffsetY * wordOffset[k][1];
context.fillText(wordArr[k], wordOffsetX, wordOffsetY);
}
}
layerPoints[n][k] = [distX, distY];
}
}
for(m = 0; m < layerPoints.length; m++) {
for(n = 0; n < layerPoints[m].length; n++) {
context.moveTo(layerPoints[m][n][0], layerPoints[m][n][1]);
if(n < layerPoints[m].length – 1) {
context.lineTo(layerPoints[m][n + 1][0], layerPoints[m][n + 1][1]);
} else {
context.moveTo(layerPoints[m][n][0], layerPoints[m][n][1]);
context.lineTo(layerPoints[m][0][0], layerPoints[m][0][1]);
}
}
}
context.stroke();
// 绘制比例:
context.beginPath();
context.setStrokeStyle(“rgba(77,168,213,0.85)”);
context.setFillStyle(“rgba(77,168,213,0.85)”);
let isFirstPoint = true;
let tmpPoints = [];
for(m = 0; m < angleNum; m++) {
tmpPoints = centerPoint;
if(dataArr[m] > 0) {
for(n = 0; n < layerNum; n++) {
if(dataArr[m] == (n + 1)) {
tmpPoints = layerPoints[n][m];
break;
}
}
}
if(isFirstPoint) {
context.moveTo(tmpPoints[0], tmpPoints[1]);
isFirstPoint = false;
} else {
context.lineTo(tmpPoints[0], tmpPoints[1]);
}
}
context.fill();
context.stroke();
context.closePath();
// 绘制圆点：
for(m = 0; m < angleNum; m++) {
tmpPoints = centerPoint;
if(dataArr[m] > 0) {
for(n = 0; n < layerNum; n++) {
if(dataArr[m] == (n + 1)) {
tmpPoints = layerPoints[n][m];
break;
}
}
}
context.beginPath();
context.setStrokeStyle(“rgba(61,147,189,0.9)”);
context.setFillStyle(“rgba(61,147,189,0.9)”);
context.closePath();
context.arc(tmpPoints[0], tmpPoints[1], circleWidth, 0, 2 * Math.PI, false);
context.closePath();
context.fill();
context.stroke();
}
wx.drawCanvas({
canvasId: ‘radarCanvas’,
actions: context.getActions()
});
}
};
let rpx = (param) => {
if(windowWidth == 0) {
wx.getSystemInfo({
success: function (res) {
windowWidth = res.windowWidth;
}
});
}
return Number((windowWidth / 750 * param).toFixed(2));
};
let getXParam = (angle) => {
let param = 1;
if(angle >= 0 && angle < 90) {
param = 1;
} else if(angle >= 90 && angle < 180) {
param = -1;
angle = 180 – angle;
} else if(angle >= 180 && angle < 270) {
param = -1;
angle = angle – 180;
} else if(angle >= 270 && angle <= 360) {
param = 1;
angle = 360 – angle;
}
let angleCos = Math.cos(Math.PI / 180 * angle);
if(angleCos < 0) {
angleCos = angleCos * -1;
}
return angleCos * param;
};
let getYParam = (angle) => {
let param = 1;
if(angle >= 0 && angle < 90) {
param = 1;
} else if(angle >= 90 && angle < 180) {
param = 1;
angle = 180 – angle;
} else if(angle >= 180 && angle < 270) {
param = -1;
angle = angle – 180;
} else if(angle >= 270 && angle <= 360) {
param = -1;
angle = 360 – angle;
}
let angleSin = Math.sin(Math.PI / 180 * angle);
if(angleSin < 0) {
angleSin = angleSin * -1;
}
return angleSin * param;
};
module.exports = {
radar
};
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