Web前端笔记-画布拖动及放缩（two.js）

程序运行截图如下：

结构图如下：

关键代码如下：

界面调用

HelloWorld.vue

<template>
  <div>
    <div id="draw-shapes"></div>
  </div>
</template>
 
<script>
 
  import "JS/two"
  import "JS/zui";
  import {demo1} from "JS/test1";
 
  export default {
  name: 'HelloWorld',
  data () {
    return {
      msg: 'Welcome to Your Vue.js App'
    }
  },
    mounted() {
 
      demo1();
    }
  }
</script>
 
 
<style scoped>
 
</style>

js关键代码如下：

zui.js

(function(Two){
 
  let _ = Two.Utils;
 
  let Surface = function(object) {
 
    this.object = object;
 
  };
 
  _.extend(Surface.prototype, {
 
    limits: function(min, max) {
 
      let min_exists = !_.isUndefined(min);
      let max_exists = !_.isUndefined(max);
 
      if (!max_exists && !min_exists) {
        return { min: this.min, max: this.max };
      }
 
      this.min = min_exists ? min : this.min;
      this.max = max_exists ? max : this.max;
 
      return this;
 
    },
 
    apply: function(px, py, s) {
      this.object.translation.set(px, py);
      this.object.scale = s;
      return this;
    }
 
  });
 
  let ZUI = Two.ZUI = function(group, domElement) {
 
    this.limits = {
 
      scale: ZUI.Limit.clone(),
      x: ZUI.Limit.clone(),
      y: ZUI.Limit.clone()
    };
 
    this.viewport = domElement || document.body;
    this.viewportOffset = {
      matrix: new Two.Matrix()
    };
 
    this.surfaceMatrix = new Two.Matrix();
 
    this.surfaces = [];
    this.reset();
    this.updateSurface();
 
    this.add(new Surface(group));
 
  };
 
  _.extend(ZUI, {
 
    Surface: Surface,
 
    Clamp: function(v, min, max) {
      return Math.min(Math.max(v, min), max);
    },
 
    Limit: {
 
      min: -Infinity,
      max: Infinity,
      clone: function() {
 
        let result = {};
        for (let k in this) {
 
          result[k] = this[k];
        }
        return result;
      }
    },
 
    TranslateMatrix: function(m, x, y) {
 
      m.elements[2] += x;
      m.elements[5] += y;
      return m;
    },
 
    PositionToScale: function(pos){
 
      return Math.exp(pos);
    },
 
    ScaleToPosition: function(scale){
 
      return Math.log(scale);
    }
 
  });
 
  _.extend(ZUI.prototype, {
 
    constructor: ZUI,
 
    add: function(surface){
 
      this.surfaces.push(surface);
      let limits = surface.limits();
      this.addLimits(limits.min, limits.max);
      return this;
    },
 
    addLimits: function(min, max, type) {
 
      type = type || 'scale';
 
      if (!_.isUndefined(min)){
 
        if(this.limits[type].min){
 
          this.limits[type].min = Math.max(min, this.limits[type].min);
        }
        else{
 
          this.limits[type].min = min;
        }
      }
 
      if(_.isUndefined(max)){
 
        return this;
      }
 
      if(this.limits[type].max){
 
        this.limits[type].max = Math.min(max, this.limits[type].max);
      }
      else{
 
        this.limits[type].max = max;
      }
 
      return this;
 
    },
 
    clientToSurface: function(x, y) {
 
      this.updateOffset();
      let m = this.surfaceMatrix.inverse();
      let n = this.viewportOffset.matrix.inverse().multiply(x, y, 1);
      return m.multiply.apply(m, _.toArray(n));
    },
 
    surfaceToClient: function(v) {
 
      this.updateOffset();
      let vo = this.viewportOffset.matrix.clone();
      let sm = this.surfaceMatrix.multiply.apply(this.surfaceMatrix, _.toArray(v));
      return vo.multiply.apply(vo, _.toArray(sm));
    },
 
    graphicMove: function(clientX, clientY){
 
      let dx = clientX;
      let dy = clientY;
      this.translateSurface(dx, dy);
      return this;
    },
 
    zoomBy: function(byF, clientX, clientY){
 
      let s = ZUI.PositionToScale(this.zoom + byF);
      this.zoomSet(s, clientX, clientY);
      return this;
    },
 
    zoomSet: function(zoom, clientX, clientY) {
 
      let newScale = this.fitToLimits(zoom);
      this.zoom = ZUI.ScaleToPosition(newScale);
 
      if (newScale === this.scale) {
 
        return this;
      }
 
      let sf = this.clientToSurface(clientX, clientY);
      let scaleBy = newScale / this.scale;
 
      this.surfaceMatrix.scale(scaleBy);
      this.scale = newScale;
 
      let c = this.surfaceToClient(sf);
      let dx = clientX - c.x;
      let dy = clientY - c.y;
      this.translateSurface(dx, dy);
 
      return this;
    },
 
    translateSurface: function(x, y) {
 
      ZUI.TranslateMatrix(this.surfaceMatrix, x, y);
      this.updateSurface();
      return this;
    },
 
    updateOffset: function() {
 
      let rect = this.viewport.getBoundingClientRect();
      _.extend(this.viewportOffset, rect);
 
      this.viewportOffset.left -= document.body.scrollLeft;
      this.viewportOffset.top -= document.body.scrollTop;
 
      this.viewportOffset.matrix
        .identity()
        .translate(this.viewportOffset.left, this.viewportOffset.top);
 
      return this;
 
    },
 
    updateSurface: function() {
 
      let e = this.surfaceMatrix.elements;
      for(let i = 0; i < this.surfaces.length; i++){
 
        this.surfaces[i].apply(e[2], e[5], e[0]);
      }
      return this;
    },
 
    reset: function() {
      this.zoom = 0;
      this.scale = 1.0;
      this.surfaceMatrix.identity();
      return this;
    },
 
    fitToLimits: function(s) {
      return ZUI.Clamp(s, this.limits.scale.min, this.limits.scale.max);
    }
 
  });
 
})
((typeof global !== 'undefined' ? global : (this || window)).Two);

test1.js

;
 
import * as Two from "JS/two";
import * as $ from "JS/jquery"
 
 
export function demo1(){
 
  let elem = document.getElementById('draw-shapes');
  let params = {
    type: Two.Types['webgl'],
    fullscreen: true,
    autostart: true
  }
 
  let two = new Two(params).appendTo(elem);
 
  let circle = two.makeCircle(0, 0, 50);
  let rect = two.makeRectangle(2000, 2000, 100, 100);
 
  circle.fill = '#FF8000';
  circle.stroke = 'orangered';
  circle.linewidth = 5;
 
  rect.fill = 'rgb(0, 200, 255)';
  rect.opacity = 5;
  rect.noStroke();
 
  two.update();
 
  let zui = new Two.ZUI(two.scene);
  zui.addLimits(0.06, 8);
 
  let $stage = $(two.renderer.domElement);
  $stage.bind('mousewheel wheel' , function (event){
 
    let e = event.originalEvent;
    e.stopPropagation();
    e.preventDefault();
 
    let dy = (e.wheelDeltaY || -e.deltaY) / 1000;
    zui.zoomBy(dy, e.clientX, e.clientY);
  });
 
  let isPressed = false;
  let originalPositionX = 0;
  let originalPositionY = 0;
  $stage.bind('mouseup', function(event){
 
    isPressed = false;
  });
 
  $stage.bind('mousemove', function(event){
 
    if(isPressed){
 
      let boolX = event.clientX - originalPositionX;
      let boolY = event.clientY - originalPositionY;
      zui.graphicMove(boolX, boolY);
      originalPositionX = event.clientX;
      originalPositionY = event.clientY;
    }
  });
 
  $stage.bind('mousedown', function(event){
 
    isPressed = true;
    originalPositionX = event.clientX;
    originalPositionY = event.clientY;
  });
}