post init

bundle.js

@@ -239,11 +239,28 @@ class Vector {
         return Vector.dot(Vector.sub(a, b), Vector.sub(a, b));
     }
 }
-const init = (opt)=>{
+class OriginVector extends Vector {
-    if (window.doodler) throw 'Doodler has already been initialized in this window';
+    origin;
-    window.doodler = new Doodler(opt);
+    get halfwayPoint() {
-    window.doodler.init();
+        return {
-};
+            x: this.mag() / 2 * Math.sin(this.heading()) + this.origin.x,
+            y: this.mag() / 2 * Math.cos(this.heading()) + this.origin.y
+        };
+    }
+    constructor(origin, p){
+        super(p.x, p.y, p.z);
+        this.origin = origin;
+    }
+    static from(origin, p) {
+        const v = {
+            x: p.x - origin.x,
+            y: p.y - origin.y
+        };
+        return new OriginVector(origin, v);
+    }
+}
+const easeInOut = (x)=>x < 0.5 ? 4 * x * x * x : 1 - Math.pow(-2 * x + 2, 3) / 2;
+const map = (value, x1, y1, x2, y2)=>(value - x1) * (y2 - x2) / (y1 - x1) + x2;
 class Doodler {
     ctx;
     _canvas;
@@ -258,6 +275,7 @@ class Doodler {
     }
     draggables = [];
     clickables = [];
+    dragTarget;
     constructor({ width , height , canvas , bg , framerate  }){
         if (!canvas) {
             canvas = document.createElement('canvas');
@@ -269,21 +287,13 @@ class Doodler {
         canvas.height = height;
         this._canvas = canvas;
         const ctx = canvas.getContext('2d');
-        console.log(ctx);
         if (!ctx) throw 'Unable to initialize Doodler: Canvas context not found';
         this.ctx = ctx;
     }
     init() {
         this._canvas.addEventListener('mousedown', (e)=>this.onClick(e));
         this._canvas.addEventListener('mouseup', (e)=>this.offClick(e));
-        this._canvas.addEventListener('mousemove', (e)=>{
+        this._canvas.addEventListener('mousemove', (e)=>this.onDrag(e));
-            const rect = this._canvas.getBoundingClientRect();
-            this.mouseX = e.clientX - rect.left;
-            this.mouseY = e.clientY - rect.top;
-            for (const d of this.draggables.filter((d)=>d.beingDragged)){
-                d.point.add(e.movementX, e.movementY);
-            }
-        });
         this.startDrawLoop();
     }
     timer;
@@ -388,6 +398,12 @@ class Doodler {
         cb();
         this.ctx.restore();
     }
+    drawScaled(scale, cb) {
+        this.ctx.save();
+        this.ctx.transform(scale, 0, 0, scale, 0, 0);
+        cb();
+        this.ctx.restore();
+    }
     drawImage(img, at, w, h) {
         w && h ? this.ctx.drawImage(img, at.x, at.y, w, h) : this.ctx.drawImage(img, at.x, at.y);
     }
@@ -436,11 +452,12 @@ class Doodler {
     unregisterClickable(cb) {
         this.clickables = this.clickables.filter((c)=>c.onClick !== cb);
     }
-    addDragEvents({ onDragEnd , onDragStart , point  }) {
+    addDragEvents({ onDragEnd , onDragStart , onDrag , point  }) {
         const d = this.draggables.find((d)=>d.point === point);
         if (d) {
             d.onDragEnd = onDragEnd;
             d.onDragStart = onDragStart;
+            d.onDrag = onDrag;
         }
     }
     onClick(e) {
@@ -449,6 +466,7 @@ class Doodler {
             if (d.point.dist(mouse) <= d.radius) {
                 d.beingDragged = true;
                 d.onDragStart?.call(null);
+                this.dragTarget = d;
             } else d.beingDragged = false;
         }
         for (const c of this.clickables){
@@ -462,6 +480,19 @@ class Doodler {
             d.beingDragged = false;
             d.onDragEnd?.call(null);
         }
+        this.dragTarget = undefined;
+    }
+    onDrag(e) {
+        this._canvas.getBoundingClientRect();
+        this.mouseX = e.offsetX;
+        this.mouseY = e.offsetY;
+        for (const d of this.draggables.filter((d)=>d.beingDragged)){
+            d.point.add(e.movementX, e.movementY);
+            d.onDrag && d.onDrag({
+                x: e.movementX,
+                y: e.movementY
+            });
+        }
     }
     uiElements = new Map();
     uiDrawing = {
@@ -498,39 +529,283 @@ class Doodler {
         this.uiElements.delete(id);
     }
 }
+class ZoomableDoodler extends Doodler {
+    scale = 1;
+    dragging = false;
+    origin = {
+        x: 0,
+        y: 0
+    };
+    mouse = {
+        x: 0,
+        y: 0
+    };
+    previousTouchLength;
+    touchTimer;
+    hasDoubleTapped = false;
+    zooming = false;
+    scaleAround = {
+        x: 0,
+        y: 0
+    };
+    maxScale = 4;
+    constructor(options){
+        super(options);
+        this._canvas.addEventListener('wheel', (e)=>{
+            this.scaleAtMouse(e.deltaY < 0 ? 1.1 : .9);
+            if (this.scale === 1) {
+                this.origin.x = 0;
+                this.origin.y = 0;
+            }
+        });
+        this._canvas.addEventListener('dblclick', (e)=>{
+            e.preventDefault();
+            this.scale = 1;
+            this.origin.x = 0;
+            this.origin.y = 0;
+            this.ctx.setTransform(1, 0, 0, 1, 0, 0);
+        });
+        this._canvas.addEventListener('mousedown', (e)=>{
+            e.preventDefault();
+            this.dragging = true;
+        });
+        this._canvas.addEventListener('mouseup', (e)=>{
+            e.preventDefault();
+            this.dragging = false;
+        });
+        this._canvas.addEventListener('mouseleave', (e)=>{
+            this.dragging = false;
+        });
+        this._canvas.addEventListener('mousemove', (e)=>{
+            const prev = this.mouse;
+            this.mouse = {
+                x: e.offsetX,
+                y: e.offsetY
+            };
+            if (this.dragging && !this.dragTarget) this.drag(prev);
+        });
+        this._canvas.addEventListener('touchstart', (e)=>{
+            e.preventDefault();
+            if (e.touches.length === 1) {
+                const t1 = e.touches.item(0);
+                if (t1) {
+                    this.mouse = this.getTouchOffset({
+                        x: t1.clientX,
+                        y: t1.clientY
+                    });
+                }
+            } else {
+                clearTimeout(this.touchTimer);
+            }
+        });
+        this._canvas.addEventListener('touchend', (e)=>{
+            if (e.touches.length !== 2) {
+                this.previousTouchLength = undefined;
+            }
+            switch(e.touches.length){
+                case 1:
+                    break;
+                case 0:
+                    if (!this.zooming) {
+                        this.events.get('touchend')?.map((cb)=>cb(e));
+                    }
+                    break;
+            }
+            this.dragging = e.touches.length === 1;
+            clearTimeout(this.touchTimer);
+        });
+        this._canvas.addEventListener('touchmove', (e)=>{
+            e.preventDefault();
+            if (e.touches.length === 2) {
+                const t1 = e.touches.item(0);
+                const t2 = e.touches.item(1);
+                if (t1 && t2) {
+                    const vect = OriginVector.from(this.getTouchOffset({
+                        x: t1.clientX,
+                        y: t1.clientY
+                    }), {
+                        x: t2.clientX,
+                        y: t2.clientY
+                    });
+                    if (this.previousTouchLength) {
+                        const diff = this.previousTouchLength - vect.mag();
+                        this.scaleAt(vect.halfwayPoint, diff < 0 ? 1.01 : .99);
+                        this.scaleAround = {
+                            ...vect.halfwayPoint
+                        };
+                    }
+                    this.previousTouchLength = vect.mag();
+                }
+            }
+            if (e.touches.length === 1) {
+                this.dragging === true;
+                const t11 = e.touches.item(0);
+                if (t11) {
+                    const prev = this.mouse;
+                    this.mouse = this.getTouchOffset({
+                        x: t11.clientX,
+                        y: t11.clientY
+                    });
+                    this.drag(prev);
+                }
+            }
+        });
+        this._canvas.addEventListener('touchstart', (e)=>{
+            if (e.touches.length !== 1) return false;
+            if (!this.hasDoubleTapped) {
+                this.hasDoubleTapped = true;
+                setTimeout(()=>this.hasDoubleTapped = false, 300);
+                return false;
+            }
+            console.log(this.mouse);
+            if (this.scale > 1) {
+                this.frameCounter = map(this.scale, this.maxScale, 1, 0, 59);
+                this.zoomDirection = -1;
+            } else {
+                this.frameCounter = 0;
+                this.zoomDirection = 1;
+            }
+            if (this.zoomDirection > 0) this.scaleAround = {
+                ...this.mouse
+            };
+            this.events.get('doubletap')?.map((cb)=>cb(e));
+        });
+    }
+    worldToScreen(x, y) {
+        x = x * this.scale + this.origin.x;
+        y = y * this.scale + this.origin.y;
+        return {
+            x,
+            y
+        };
+    }
+    screenToWorld(x, y) {
+        x = (x - this.origin.x) / this.scale;
+        y = (y - this.origin.y) / this.scale;
+        return {
+            x,
+            y
+        };
+    }
+    scaleAtMouse(scaleBy) {
+        if (this.scale === this.maxScale && scaleBy > 1) return;
+        this.scaleAt({
+            x: this.mouse.x,
+            y: this.mouse.y
+        }, scaleBy);
+    }
+    scaleAt(p, scaleBy) {
+        this.scale = Math.min(Math.max(this.scale * scaleBy, 1), this.maxScale);
+        this.origin.x = p.x - (p.x - this.origin.x) * scaleBy;
+        this.origin.y = p.y - (p.y - this.origin.y) * scaleBy;
+        this.constrainOrigin();
+    }
+    drag(prev) {
+        if (this.scale > 1) {
+            const xOffset = this.mouse.x - prev.x;
+            const yOffset = this.mouse.y - prev.y;
+            this.origin.x += xOffset;
+            this.origin.y += yOffset;
+            this.constrainOrigin();
+        }
+    }
+    constrainOrigin() {
+        this.origin.x = Math.min(Math.max(this.origin.x, -this._canvas.width * this.scale + this._canvas.width), 0);
+        this.origin.y = Math.min(Math.max(this.origin.y, -this._canvas.height * this.scale + this._canvas.height), 0);
+    }
+    draw() {
+        this.ctx.setTransform(this.scale, 0, 0, this.scale, this.origin.x, this.origin.y);
+        this.animateZoom();
+        this.ctx.fillStyle = this.bg;
+        this.ctx.fillRect(0, 0, this.width / this.scale, this.height / this.scale);
+        super.draw();
+    }
+    getTouchOffset(p) {
+        const { x , y  } = this._canvas.getBoundingClientRect();
+        const offsetX = p.x - x;
+        const offsetY = p.y - y;
+        return {
+            x: offsetX,
+            y: offsetY
+        };
+    }
+    onDrag(e) {
+        const d = {
+            ...e,
+            movementX: e.movementX / this.scale,
+            movementY: e.movementY / this.scale
+        };
+        super.onDrag(d);
+        const { x , y  } = this.screenToWorld(e.offsetX, e.offsetY);
+        this.mouseX = x;
+        this.mouseY = y;
+    }
+    zoomDirection = -1;
+    frameCounter = 60;
+    animateZoom() {
+        if (this.frameCounter < 60) {
+            const frame = easeInOut(map(this.frameCounter, 0, 59, 0, 1));
+            switch(this.zoomDirection){
+                case 1:
+                    {
+                        this.scale = map(frame, 0, 1, 1, this.maxScale);
+                    }
+                    break;
+                case -1:
+                    {
+                        this.scale = map(frame, 0, 1, this.maxScale, 1);
+                    }
+                    break;
+            }
+            this.origin.x = this.scaleAround.x - this.scaleAround.x * this.scale;
+            this.origin.y = this.scaleAround.y - this.scaleAround.y * this.scale;
+            this.constrainOrigin();
+            this.frameCounter++;
+        }
+    }
+    events = new Map();
+    registerEvent(eventName, cb) {
+        let events = this.events.get(eventName);
+        if (!events) events = this.events.set(eventName, []).get(eventName);
+        events.push(cb);
+    }
+}
+const init = (opt, zoomable)=>{
+    if (window.doodler) throw 'Doodler has already been initialized in this window';
+    window.doodler = zoomable ? new ZoomableDoodler(opt) : new Doodler(opt);
+    window.doodler.init();
+};
 init({
     width: 400,
     height: 400
-});
+}, true);
-const movingVector = new Vector(100, 300);
+new Vector(100, 300);
-let angleMultiplier = 0;
 const v = new Vector(30, 30);
 doodler.registerDraggable(v, 20);
 const img = new Image();
 img.src = './EngineSprites.png';
 img.hidden;
 document.body.append(img);
+const p = new Vector(200, 200);
 doodler.createLayer(()=>{
-    doodler.line(new Vector(100, 100), new Vector(200, 200));
+    doodler.drawScaled(1.5, ()=>{
-    doodler.dot(new Vector(300, 300));
+        doodler.line(p.copy().add(-8, 10), p.copy().add(8, 10), {
-    doodler.fillCircle(movingVector, 6, {
+            color: 'grey',
-        color: 'red'
+            weight: 2
+        });
+        doodler.line(p.copy().add(-8, -10), p.copy().add(8, -10), {
+            color: 'grey',
+            weight: 2
+        });
+        doodler.line(p, p.copy().add(0, 12), {
+            color: 'brown',
+            weight: 4
+        });
+        doodler.line(p, p.copy().add(0, -12), {
+            color: 'brown',
+            weight: 4
+        });
     });
-    doodler.drawRect(new Vector(50, 50), movingVector.x, movingVector.y);
-    doodler.fillRect(new Vector(200, 250), 30, 10);
-    doodler.drawCenteredSquare(new Vector(200, 200), 40, {
-        color: 'purple',
-        weight: 5
-    });
-    doodler.drawBezier(new Vector(100, 150), movingVector, new Vector(150, 300), new Vector(100, 250));
-    let rotatedOrigin = new Vector(200, 200);
-    doodler.drawRotated(rotatedOrigin, Math.PI * angleMultiplier, ()=>{
-        doodler.drawCenteredSquare(rotatedOrigin, 30);
-        doodler.drawSprite(img, new Vector(0, 40), 80, 20, new Vector(160, 300), 80, 20);
-    });
-    movingVector.set((movingVector.x + 1) % 400, movingVector.y);
-    angleMultiplier += .001;
-    doodler.drawSprite(img, new Vector(0, 40), 80, 20, new Vector(100, 300), 80, 20);
 });
 document.addEventListener('keyup', (e)=>{
     e.preventDefault();

canvas.ts

@@ -1,16 +1,25 @@
 /// <reference types="./global.d.ts" />
 
-
 import { Constants } from "./geometry/constants.ts";
 import { Vector } from "./geometry/vector.ts";
+import { postInit } from "./postInit.ts";
+import { ZoomableDoodler } from "./zoomableCanvas.ts";
 
-export const init = (opt: IDoodlerOptions) => {
+export const init = (
-  if (window.doodler) throw 'Doodler has already been initialized in this window'
+  opt: IDoodlerOptions,
-  window.doodler = new Doodler(opt);
+  zoomable: boolean,
+  postInit: postInit,
+) => {
+  if (window.doodler) {
+    throw "Doodler has already been initialized in this window";
+  }
+  window.doodler = zoomable
+    ? new ZoomableDoodler(opt, postInit)
+    : new Doodler(opt, postInit);
   window.doodler.init();
-}
+};
 
-interface IDoodlerOptions {
+export interface IDoodlerOptions {
   width: number;
   height: number;
   canvas?: HTMLCanvasElement;
@@ -21,12 +30,12 @@ interface IDoodlerOptions {
 type layer = (ctx: CanvasRenderingContext2D, index: number) => void;
 
 export class Doodler {
-  private ctx: CanvasRenderingContext2D;
+  protected ctx: CanvasRenderingContext2D;
-  private _canvas: HTMLCanvasElement;
+  protected _canvas: HTMLCanvasElement;
 
   private layers: layer[] = [];
 
-  private bg: string;
+  protected bg: string;
   private framerate: number;
 
   get width() {
@@ -39,19 +48,21 @@ export class Doodler {
   private draggables: Draggable[] = [];
   private clickables: Clickable[] = [];
 
+  protected dragTarget?: Draggable;
+
   constructor({
     width,
     height,
     canvas,
     bg,
-    framerate
+    framerate,
-  }: IDoodlerOptions) {
+  }: IDoodlerOptions, postInit?: postInit) {
     if (!canvas) {
-      canvas = document.createElement('canvas');
+      canvas = document.createElement("canvas");
       document.body.append(canvas);
     }
 
-    this.bg = bg || 'white';
+    this.bg = bg || "white";
     this.framerate = framerate || 60;
 
     canvas.width = width;
@@ -59,24 +70,17 @@ export class Doodler {
 
     this._canvas = canvas;
 
-    const ctx = canvas.getContext('2d');
+    const ctx = canvas.getContext("2d");
-    console.log(ctx);
+    if (!ctx) throw "Unable to initialize Doodler: Canvas context not found";
-    if (!ctx) throw 'Unable to initialize Doodler: Canvas context not found';
     this.ctx = ctx;
+
+    postInit?.(this.ctx);
   }
 
   init() {
-    this._canvas.addEventListener('mousedown', e => this.onClick(e));
+    this._canvas.addEventListener("mousedown", (e) => this.onClick(e));
-    this._canvas.addEventListener('mouseup', e => this.offClick(e));
+    this._canvas.addEventListener("mouseup", (e) => this.offClick(e));
-    this._canvas.addEventListener('mousemove', e => {
+    this._canvas.addEventListener("mousemove", (e) => this.onDrag(e));
-      const rect = this._canvas.getBoundingClientRect();
-      this.mouseX = e.clientX - rect.left;
-      this.mouseY = e.clientY - rect.top;
-
-      for (const d of this.draggables.filter(d => d.beingDragged)) {
-        d.point.add(e.movementX, e.movementY)
-      }
-    })
     this.startDrawLoop();
   }
 
@@ -85,7 +89,8 @@ export class Doodler {
     this.timer = setInterval(() => this.draw(), 1000 / this.framerate);
   }
 
-  private draw() {
+  protected draw() {
+    this.ctx.clearRect(0, 0, this.width, this.height);
     this.ctx.fillStyle = this.bg;
     this.ctx.fillRect(0, 0, this.width, this.height);
     // for (const d of this.draggables.filter(d => d.beingDragged)) {
@@ -93,6 +98,7 @@ export class Doodler {
     // }
     for (const [i, l] of (this.layers || []).entries()) {
       l(this.ctx, i);
+      this.drawDeferred();
     }
     this.drawUI();
   }
@@ -104,11 +110,11 @@ export class Doodler {
   }
 
   deleteLayer(layer: layer) {
-    this.layers = this.layers.filter(l => l !== layer);
+    this.layers = this.layers.filter((l) => l !== layer);
   }
 
   moveLayer(layer: layer, index: number) {
-    let temp = this.layers.filter(l => l !== layer);
+    let temp = this.layers.filter((l) => l !== layer);
 
     temp = [...temp.slice(0, index), layer, ...temp.slice(index)];
 
@@ -125,7 +131,7 @@ export class Doodler {
     this.ctx.stroke();
   }
   dot(at: Vector, style?: IStyle) {
-    this.setStyle({ ...style, weight: 1 })
+    this.setStyle({ ...style, weight: 1 });
     this.ctx.beginPath();
 
     this.ctx.arc(at.x, at.y, style?.weight || 1, 0, Constants.TWO_PI);
@@ -195,21 +201,85 @@ export class Doodler {
     this.ctx.restore();
   }
 
+  drawScaled(scale: number, cb: () => void) {
+    this.ctx.save();
+    this.ctx.transform(scale, 0, 0, scale, 0, 0);
+    cb();
+    this.ctx.restore();
+  }
+
+  drawWithAlpha(alpha: number, cb: () => void) {
+    this.ctx.save();
+    this.ctx.globalAlpha = Math.min(Math.max(alpha, 0), 1);
+    cb();
+    this.ctx.restore();
+  }
+
   drawImage(img: HTMLImageElement, at: Vector): void;
   drawImage(img: HTMLImageElement, at: Vector, w: number, h: number): void;
   drawImage(img: HTMLImageElement, at: Vector, w?: number, h?: number) {
-    w && h ? this.ctx.drawImage(img, at.x, at.y, w, h) : this.ctx.drawImage(img, at.x, at.y);
+    w && h
+      ? this.ctx.drawImage(img, at.x, at.y, w, h)
+      : this.ctx.drawImage(img, at.x, at.y);
   }
-  drawSprite(img: HTMLImageElement, spritePos: Vector, sWidth: number, sHeight: number, at: Vector, width: number, height: number) {
+  drawSprite(
-    this.ctx.drawImage(img, spritePos.x, spritePos.y, sWidth, sHeight, at.x, at.y, width, height);
+    img: HTMLImageElement,
+    spritePos: Vector,
+    sWidth: number,
+    sHeight: number,
+    at: Vector,
+    width: number,
+    height: number,
+  ) {
+    this.ctx.drawImage(
+      img,
+      spritePos.x,
+      spritePos.y,
+      sWidth,
+      sHeight,
+      at.x,
+      at.y,
+      width,
+      height,
+    );
+  }
+
+  private deferredDrawings: (() => void)[] = [];
+
+  deferDrawing(cb: () => void) {
+    this.deferredDrawings.push(cb);
+  }
+
+  drawDeferred() {
+    while (this.deferredDrawings.length) {
+      this.deferredDrawings.pop()?.();
+    }
   }
 
   setStyle(style?: IStyle) {
     const ctx = this.ctx;
-    ctx.fillStyle = style?.color || style?.fillColor || 'black';
+    ctx.fillStyle = style?.color || style?.fillColor || "black";
-    ctx.strokeStyle = style?.color || style?.strokeColor || 'black';
+    ctx.strokeStyle = style?.color || style?.strokeColor || "black";
 
     ctx.lineWidth = style?.weight || 1;
+
+    ctx.textAlign = style?.textAlign || ctx.textAlign;
+    ctx.textBaseline = style?.textBaseline || ctx.textBaseline;
+  }
+
+  fillText(text: string, pos: Vector, maxWidth: number, style?: IStyle) {
+    this.setStyle(style);
+    // TODO: add text alignment to style
+    this.ctx.fillText(text, pos.x, pos.y, maxWidth);
+  }
+  strokeText(text: string, pos: Vector, maxWidth: number, style?: IStyle) {
+    this.setStyle(style);
+    // TODO: add text alignment to style
+    this.ctx.strokeText(text, pos.x, pos.y, maxWidth);
+  }
+
+  clearRect(at: Vector, width: number, height: number) {
+    this.ctx.clearRect(at.x, at.y, width, height);
   }
 
   // Interaction
@@ -217,10 +287,16 @@ export class Doodler {
   mouseX = 0;
   mouseY = 0;
 
-
+  registerDraggable(
-  registerDraggable(point: Vector, radius: number, style?: IStyle & { shape: 'square' | 'circle' }) {
+    point: Vector,
-    if (this.draggables.find(d => d.point === point)) return;
+    radius: number,
-    const id = this.addUIElement('circle', point, radius, { fillColor: '#5533ff50', strokeColor: '#5533ff50' })
+    style?: IStyle & { shape: "square" | "circle" },
+  ) {
+    if (this.draggables.find((d) => d.point === point)) return;
+    const id = this.addUIElement("circle", point, radius, {
+      fillColor: "#5533ff50",
+      strokeColor: "#5533ff50",
+    });
     this.draggables.push({ point, radius, style, id });
   }
   unregisterDraggable(point: Vector) {
@@ -229,7 +305,7 @@ export class Doodler {
         this.removeUIElement(d.id);
       }
     }
-    this.draggables = this.draggables.filter(d => d.point !== point);
+    this.draggables = this.draggables.filter((d) => d.point !== point);
   }
 
   registerClickable(p1: Vector, p2: Vector, cb: () => void) {
@@ -240,32 +316,41 @@ export class Doodler {
 
     this.clickables.push({
       onClick: cb,
-      checkBound: (p) => p.y >= top && p.x >= left && p.y <= bottom && p.x <= right
+      checkBound: (p) =>
-    })
+        p.y >= top && p.x >= left && p.y <= bottom && p.x <= right,
+    });
   }
 
   unregisterClickable(cb: () => void) {
-    this.clickables = this.clickables.filter(c => c.onClick !== cb);
+    this.clickables = this.clickables.filter((c) => c.onClick !== cb);
   }
 
   addDragEvents({
     onDragEnd,
     onDragStart,
-    point
+    onDrag,
-  }: { point: Vector, onDragEnd?: () => void, onDragStart?: () => void }) {
+    point,
-    const d = this.draggables.find(d => d.point === point);
+  }: {
+    point: Vector;
+    onDragEnd?: () => void;
+    onDragStart?: () => void;
+    onDrag?: (movement: { x: number; y: number }) => void;
+  }) {
+    const d = this.draggables.find((d) => d.point === point);
     if (d) {
       d.onDragEnd = onDragEnd;
       d.onDragStart = onDragStart;
+      d.onDrag = onDrag;
     }
   }
 
   onClick(e: MouseEvent) {
-    const mouse = new Vector(this.mouseX, this.mouseY)
+    const mouse = new Vector(this.mouseX, this.mouseY);
     for (const d of this.draggables) {
       if (d.point.dist(mouse) <= d.radius) {
         d.beingDragged = true;
         d.onDragStart?.call(null);
+        this.dragTarget = d;
       } else d.beingDragged = false;
     }
 
@@ -281,34 +366,64 @@ export class Doodler {
       d.beingDragged = false;
       d.onDragEnd?.call(null);
     }
+    this.dragTarget = undefined;
+  }
+
+  onDrag(e: MouseEvent) {
+    const rect = this._canvas.getBoundingClientRect();
+    this.mouseX = e.offsetX;
+    this.mouseY = e.offsetY;
+    // this.mouseX = e.clientX - rect.left;
+    // this.mouseY = e.clientY - rect.top;
+
+    for (const d of this.draggables.filter((d) => d.beingDragged)) {
+      d.point.add(e.movementX, e.movementY);
+      d.onDrag && d.onDrag({ x: e.movementX, y: e.movementY });
+    }
   }
 
   // UI Layer
   uiElements: Map<string, [keyof uiDrawing, ...any]> = new Map();
   private uiDrawing: uiDrawing = {
     rectangle: (...args: any[]) => {
-      !args[3].noFill && this.fillRect(args[0], args[1], args[2], args[3])
+      !args[3].noFill && this.fillRect(args[0], args[1], args[2], args[3]);
-      !args[3].noStroke && this.drawRect(args[0], args[1], args[2], args[3])
+      !args[3].noStroke && this.drawRect(args[0], args[1], args[2], args[3]);
     },
     square: (...args: any[]) => {
-      !args[2].noFill && this.fillSquare(args[0], args[1], args[2])
+      !args[2].noFill && this.fillSquare(args[0], args[1], args[2]);
-      !args[2].noStroke && this.drawSquare(args[0], args[1], args[2])
+      !args[2].noStroke && this.drawSquare(args[0], args[1], args[2]);
     },
     circle: (...args: any[]) => {
-      !args[2].noFill && this.fillCircle(args[0], args[1], args[2])
+      !args[2].noFill && this.fillCircle(args[0], args[1], args[2]);
-      !args[2].noStroke && this.drawCircle(args[0], args[1], args[2])
+      !args[2].noStroke && this.drawCircle(args[0], args[1], args[2]);
     },
-  }
+  };
 
   private drawUI() {
     for (const [shape, ...args] of this.uiElements.values()) {
-      this.uiDrawing[shape].apply(null, args as [])
+      this.uiDrawing[shape].apply(null, args as []);
     }
   }
 
-  addUIElement(shape: 'rectangle', at: Vector, width: number, height: number, style?: IStyle): string;
+  addUIElement(
-  addUIElement(shape: 'square', at: Vector, size: number, style?: IStyle): string;
+    shape: "rectangle",
-  addUIElement(shape: 'circle', at: Vector, radius: number, style?: IStyle): string;
+    at: Vector,
+    width: number,
+    height: number,
+    style?: IStyle,
+  ): string;
+  addUIElement(
+    shape: "square",
+    at: Vector,
+    size: number,
+    style?: IStyle,
+  ): string;
+  addUIElement(
+    shape: "circle",
+    at: Vector,
+    radius: number,
+    style?: IStyle,
+  ): string;
   addUIElement(shape: keyof uiDrawing, ...args: any[]) {
     const id = crypto.randomUUID();
     for (const arg of args) {
@@ -331,6 +446,15 @@ interface IStyle {
 
   noStroke?: boolean;
   noFill?: boolean;
+
+  textAlign?: "center" | "end" | "left" | "right" | "start";
+  textBaseline?:
+    | "alphabetic"
+    | "top"
+    | "hanging"
+    | "middle"
+    | "ideographic"
+    | "bottom";
 }
 
 interface IDrawable {
@@ -340,20 +464,21 @@ interface IDrawable {
 type Draggable = {
   point: Vector;
   radius: number;
-  style?: IStyle & { shape: 'square' | 'circle' };
+  style?: IStyle & { shape: "square" | "circle" };
   beingDragged?: boolean;
   id: string;
   onDragStart?: () => void;
   onDragEnd?: () => void;
-}
+  onDrag?: (dragDistance: { x: number; y: number }) => void;
+};
 
 type Clickable = {
   onClick: () => void;
   checkBound: (p: Vector) => boolean;
-}
+};
 
 type uiDrawing = {
   circle: () => void;
   square: () => void;
   rectangle: () => void;
-}
+};

geometry/vector.ts

@@ -2,7 +2,7 @@
 
 import { Constants } from "./constants.ts";
 
-export class Vector {
+export class Vector implements Point {
   x: number;
   y: number;
   z: number;
@@ -278,3 +278,34 @@ export class Vector {
     return Vector.dot(Vector.sub(a, b), Vector.sub(a, b))
   }
 }
+
+export class OriginVector extends Vector {
+  origin: Point;
+
+  get halfwayPoint() {
+    return {
+      x: (this.mag()/2 * Math.sin(this.heading())) + this.origin.x,
+      y: (this.mag()/2 * Math.cos(this.heading())) + this.origin.y
+    }
+  }
+
+  constructor(origin: Point, p: Point) {
+    super(p.x, p.y, p.z);
+    this.origin = origin;
+  }
+
+  static from(origin: Point, p: Point) {
+    const v = {
+      x: p.x - origin.x,
+      y: p.y - origin.y,
+    };
+
+    return new OriginVector(origin, v);
+  }
+}
+
+export interface Point {
+  x: number;
+  y: number;
+  z?: number;
+}

main.ts

@@ -5,7 +5,7 @@ import { Vector, initializeDoodler } from './mod.ts'
 initializeDoodler({
   width: 400,
   height: 400
-})
+}, true);
 
 const movingVector = new Vector(100, 300);
 let angleMultiplier = 0;
@@ -16,28 +16,35 @@ img.src = './EngineSprites.png'
 img.hidden
 document.body.append(img)
 
+const p = new Vector(200, 200);
+
 doodler.createLayer(() => {
 
-  doodler.line(new Vector(100, 100), new Vector(200, 200))
+  // doodler.line(new Vector(100, 100), new Vector(200, 200))
-  doodler.dot(new Vector(300, 300))
+  // doodler.dot(new Vector(300, 300))
-  doodler.fillCircle(movingVector, 6, { color: 'red' });
+  // doodler.fillCircle(movingVector, 6, { color: 'red' });
-  doodler.drawRect(new Vector(50, 50), movingVector.x, movingVector.y);
+  // doodler.drawRect(new Vector(50, 50), movingVector.x, movingVector.y);
-  doodler.fillRect(new Vector(200, 250), 30, 10)
+  // doodler.fillRect(new Vector(200, 250), 30, 10)
 
-  doodler.drawCenteredSquare(new Vector(200, 200), 40, { color: 'purple', weight: 5 })
+  // doodler.drawCenteredSquare(new Vector(200, 200), 40, { color: 'purple', weight: 5 })
-  doodler.drawBezier(new Vector(100, 150), movingVector, new Vector(150, 300), new Vector(100, 250))
+  // doodler.drawBezier(new Vector(100, 150), movingVector, new Vector(150, 300), new Vector(100, 250))
 
-  let rotatedOrigin = new Vector(200, 200)
+  // let rotatedOrigin = new Vector(200, 200)
-  doodler.drawRotated(rotatedOrigin, Math.PI * angleMultiplier, () => {
+  // doodler.drawRotated(rotatedOrigin, Math.PI * angleMultiplier, () => {
-    doodler.drawCenteredSquare(rotatedOrigin, 30)
+  //   doodler.drawCenteredSquare(rotatedOrigin, 30)
-    doodler.drawSprite(img, new Vector(0, 40), 80, 20, new Vector(160, 300), 80, 20)
+  //   doodler.drawSprite(img, new Vector(0, 40), 80, 20, new Vector(160, 300), 80, 20)
-  })
+  // })
 
 
-  movingVector.set((movingVector.x + 1) % 400, movingVector.y);
+  // movingVector.set((movingVector.x + 1) % 400, movingVector.y);
-  angleMultiplier += .001;
+  // angleMultiplier += .001;
 
-  doodler.drawSprite(img, new Vector(0, 40), 80, 20, new Vector(100, 300), 80, 20)
+  // doodler.drawSprite(img, new Vector(0, 40), 80, 20, new Vector(100, 300), 80, 20)
+
+  doodler.drawScaled(1.5, () => {doodler.line(p.copy().add(-8,10), p.copy().add(8,10), {color: 'grey', weight: 2})
+  doodler.line(p.copy().add(-8,-10), p.copy().add(8,-10), {color: 'grey', weight: 2})
+  doodler.line(p, p.copy().add(0,12), {color: 'brown', weight: 4})
+  doodler.line(p, p.copy().add(0,-12), {color: 'brown', weight: 4})})
 });
 
 document.addEventListener('keyup', e => {

postInit.ts

@@ -0,0 +1 @@
+export type postInit = (ctx: CanvasRenderingContext2D) => void;

timing/EaseInOut.ts

@@ -0,0 +1,2 @@
+export const easeInOut = (x: number) =>
+  x < 0.5 ? 4 * x * x * x : 1 - Math.pow(-2 * x + 2, 3) / 2;

timing/Map.ts

@@ -0,0 +1,2 @@
+export const map = (value: number, x1: number, y1: number, x2: number, y2: number) => 
+  (value - x1) * (y2 - x2) / (y1 - x1) + x2;

zoomableCanvas.ts

@@ -0,0 +1,298 @@
+import { Doodler, IDoodlerOptions } from "./canvas.ts";
+import { OriginVector, Point } from "./geometry/vector.ts";
+import { postInit } from "./postInit.ts";
+import { easeInOut } from "./timing/EaseInOut.ts";
+import { map } from "./timing/Map.ts";
+
+type TouchEventCallback = (e: TouchEvent) => void;
+
+export class ZoomableDoodler extends Doodler {
+  private scale = 1;
+  dragging = false;
+  private origin: Point = {
+    x: 0,
+    y: 0,
+  };
+
+  mouse = {
+    x: 0,
+    y: 0,
+  };
+
+  private previousTouchLength?: number;
+
+  private touchTimer?: number;
+
+  private hasDoubleTapped = false;
+  private zooming = false;
+  scaleAround: Point = { x: 0, y: 0 };
+
+  maxScale = 4;
+
+  constructor(options: IDoodlerOptions, postInit?: postInit) {
+    super(options, postInit);
+
+    this._canvas.addEventListener("wheel", (e) => {
+      this.scaleAtMouse(e.deltaY < 0 ? 1.1 : .9);
+      if (this.scale === 1) {
+        this.origin.x = 0;
+        this.origin.y = 0;
+      }
+    });
+    this._canvas.addEventListener("dblclick", (e) => {
+      e.preventDefault();
+      this.scale = 1;
+      this.origin.x = 0;
+      this.origin.y = 0;
+      this.ctx.setTransform(1, 0, 0, 1, 0, 0);
+    });
+    this._canvas.addEventListener("mousedown", (e) => {
+      e.preventDefault();
+      this.dragging = true;
+    });
+    this._canvas.addEventListener("mouseup", (e) => {
+      e.preventDefault();
+      this.dragging = false;
+    });
+    this._canvas.addEventListener("mouseleave", (e) => {
+      this.dragging = false;
+    });
+    this._canvas.addEventListener("mousemove", (e) => {
+      const prev = this.mouse;
+      this.mouse = {
+        x: e.offsetX,
+        y: e.offsetY,
+      };
+      if (this.dragging && !this.dragTarget) this.drag(prev);
+    });
+
+    this._canvas.addEventListener("touchstart", (e) => {
+      e.preventDefault();
+      if (e.touches.length === 1) {
+        const t1 = e.touches.item(0);
+        if (t1) {
+          this.mouse = this.getTouchOffset({
+            x: t1.clientX,
+            y: t1.clientY,
+          });
+        }
+        // this.touchTimer = setTimeout(() => {
+        //   this.dragging = true;
+        // }, 100)
+      } else {
+        clearTimeout(this.touchTimer);
+      }
+    });
+    this._canvas.addEventListener("touchend", (e) => {
+      if (e.touches.length !== 2) {
+        this.previousTouchLength = undefined;
+      }
+
+      switch (e.touches.length) {
+        case 1:
+          break;
+        case 0:
+          if (!this.zooming) {
+            this.events.get("touchend")?.map((cb) => cb(e));
+          }
+          break;
+      }
+
+      this.dragging = e.touches.length === 1;
+      clearTimeout(this.touchTimer);
+    });
+    this._canvas.addEventListener("touchmove", (e) => {
+      e.preventDefault();
+
+      if (e.touches.length === 2) {
+        const t1 = e.touches.item(0);
+        const t2 = e.touches.item(1);
+
+        if (t1 && t2) {
+          const vect = OriginVector.from(
+            this.getTouchOffset({
+              x: t1.clientX,
+              y: t1.clientY,
+            }),
+            {
+              x: t2.clientX,
+              y: t2.clientY,
+            },
+          );
+
+          if (this.previousTouchLength) {
+            const diff = this.previousTouchLength - vect.mag();
+            this.scaleAt(vect.halfwayPoint, diff < 0 ? 1.01 : .99);
+            this.scaleAround = { ...vect.halfwayPoint };
+          }
+          this.previousTouchLength = vect.mag();
+        }
+      }
+
+      if (e.touches.length === 1) {
+        this.dragging === true;
+        const t1 = e.touches.item(0);
+        if (t1) {
+          const prev = this.mouse;
+          this.mouse = this.getTouchOffset({
+            x: t1.clientX,
+            y: t1.clientY,
+          });
+          this.drag(prev);
+        }
+      }
+    });
+
+    this._canvas.addEventListener("touchstart", (e) => {
+      if (e.touches.length !== 1) return false;
+
+      if (!this.hasDoubleTapped) {
+        this.hasDoubleTapped = true;
+        setTimeout(() => this.hasDoubleTapped = false, 300);
+        return false;
+      }
+
+      // this.ctx.setTransform(1, 0, 0, 1, 0, 0);
+      // this.scale = 1;
+      // this.origin.x = 0;
+      // this.origin.y = 0;
+
+      console.log(this.mouse);
+
+      if (this.scale > 1) {
+        this.frameCounter = map(this.scale, this.maxScale, 1, 0, 59);
+        this.zoomDirection = -1;
+      } else {
+        this.frameCounter = 0;
+        this.zoomDirection = 1;
+      }
+      if (this.zoomDirection > 0) {
+        this.scaleAround = { ...this.mouse };
+      }
+
+      this.events.get("doubletap")?.map((cb) => cb(e));
+    });
+  }
+
+  worldToScreen(x: number, y: number) {
+    x = x * this.scale + this.origin.x;
+    y = y * this.scale + this.origin.y;
+    return { x, y };
+  }
+  screenToWorld(x: number, y: number) {
+    x = (x - this.origin.x) / this.scale;
+    y = (y - this.origin.y) / this.scale;
+    return { x, y };
+  }
+  scaleAtMouse(scaleBy: number) {
+    if (this.scale === this.maxScale && scaleBy > 1) return;
+    this.scaleAt({
+      x: this.mouse.x,
+      y: this.mouse.y,
+    }, scaleBy);
+  }
+  scaleAt(p: Point, scaleBy: number) {
+    this.scale = Math.min(Math.max(this.scale * scaleBy, 1), this.maxScale);
+    this.origin.x = p.x - (p.x - this.origin.x) * scaleBy;
+    this.origin.y = p.y - (p.y - this.origin.y) * scaleBy;
+    this.constrainOrigin();
+  }
+  drag(prev: Point) {
+    if (this.scale > 1) {
+      const xOffset = this.mouse.x - prev.x;
+      const yOffset = this.mouse.y - prev.y;
+      this.origin.x += xOffset;
+      this.origin.y += yOffset;
+      this.constrainOrigin();
+    }
+  }
+  constrainOrigin() {
+    this.origin.x = Math.min(
+      Math.max(
+        this.origin.x,
+        (-this._canvas.width * this.scale) + this._canvas.width,
+      ),
+      0,
+    );
+    this.origin.y = Math.min(
+      Math.max(
+        this.origin.y,
+        (-this._canvas.height * this.scale) + this._canvas.height,
+      ),
+      0,
+    );
+  }
+
+  draw() {
+    this.ctx.setTransform(
+      this.scale,
+      0,
+      0,
+      this.scale,
+      this.origin.x,
+      this.origin.y,
+    );
+    this.animateZoom();
+    this.ctx.fillStyle = this.bg;
+    this.ctx.fillRect(0, 0, this.width / this.scale, this.height / this.scale);
+    super.draw();
+  }
+
+  getTouchOffset(p: Point) {
+    const { x, y } = this._canvas.getBoundingClientRect();
+    const offsetX = p.x - x;
+    const offsetY = p.y - y;
+
+    return {
+      x: offsetX,
+      y: offsetY,
+    };
+  }
+
+  onDrag(e: MouseEvent): void {
+    const d = {
+      ...e,
+      movementX: e.movementX / this.scale,
+      movementY: e.movementY / this.scale,
+    };
+    super.onDrag(d);
+    const { x, y } = this.screenToWorld(e.offsetX, e.offsetY);
+    this.mouseX = x;
+    this.mouseY = y;
+  }
+
+  zoomDirection = -1;
+  frameCounter = 60;
+  animateZoom() {
+    if (this.frameCounter < 60) {
+      const frame = easeInOut(map(this.frameCounter, 0, 59, 0, 1));
+      switch (this.zoomDirection) {
+        case 1:
+          {
+            this.scale = map(frame, 0, 1, 1, this.maxScale);
+          }
+          break;
+        case -1:
+          {
+            this.scale = map(frame, 0, 1, this.maxScale, 1);
+          }
+          break;
+      }
+      this.origin.x = this.scaleAround.x - (this.scaleAround.x * this.scale);
+      this.origin.y = this.scaleAround.y - (this.scaleAround.y * this.scale);
+      this.constrainOrigin();
+
+      this.frameCounter++;
+    }
+  }
+
+  events: Map<string, TouchEventCallback[]> = new Map();
+  registerEvent(
+    eventName: "touchend" | "touchstart" | "touchmove" | "doubletap",
+    cb: TouchEventCallback,
+  ) {
+    let events = this.events.get(eventName);
+    if (!events) events = this.events.set(eventName, []).get(eventName)!;
+    events.push(cb);
+  }
+}