From 673e9c13aea6cd1b11f5ca3e1f6edd474bbb1a19 Mon Sep 17 00:00:00 2001
From: sanine <sanine.not@pm.me>
Date: Fri, 31 Mar 2023 17:17:27 -0500
Subject: implement nice map grid

---
 src/Canvas.js | 127 +++-------------------------------------------------------
 1 file changed, 5 insertions(+), 122 deletions(-)

(limited to 'src/Canvas.js')

diff --git a/src/Canvas.js b/src/Canvas.js
index 6dff7bd..f3db3e0 100644
--- a/src/Canvas.js
+++ b/src/Canvas.js
@@ -1,142 +1,25 @@
-import { clamp } from './modules/Util.js';
-
 class Canvas {
-	constructor(rootId) {
-		const root = document.getElementById(rootId);
-
+	constructor(parentElement) {
 		this.element = document.createElement('canvas');
 		this.context = this.element.getContext('2d');
-
-		/* state variables */
-		this.scale = 1;
-		this.zoom = 1;
-		const ZOOM_SPEED = 1.2;
-		
-		this.mouse = {
-			screenPos: { x: 0, y: 0 },
-			drawingPos: { x: 0, y: 0 },
-		};
-		this.pan = { x: 0, y: 0 };
-		this.panning = false;
-
-		/* callbacks */
-		this.onDraw = null;
-		this.onMouseMove = null;
-		this.onMouseDown = null;
-		this.onMouseUp = null;
-
-		/* register event listeners */
-
-		/* mouse movement */
-		this.element.addEventListener('mousemove', e => {
-			this.mouse.screenPos.x = e.offsetX;
-			this.mouse.screenPos.y = e.offsetY;
-
-			const [xd, yd] = this.screenToDrawingPos(e.offsetX, e.offsetY);
-			
-			/* compute movement */
-			const dx = e.movementX / (this.zoom * this.scale);
-			const dy = e.movementY / (this.zoom * this.scale);
-
-			/* pan? */
-			if (this.panning) {
-				this.pan.x += dx;
-				this.pan.y += dy;
-				this.setTransform();
-			}
-
-			this.mouse.drawingPos.x = xd;
-			this.mouse.drawingPos.y = yd;
-
-			if (this.onMouseMove) this.onMouseMove(this.mousePos);
-		});
-
-		/* clicking */
-		this.element.addEventListener('mousedown', e => {
-			e.preventDefault();
-			if (e.button === 1) this.panning = true;
-			if (this.onMouseDown) this.onMouseDown(e);
-		});
-		this.element.addEventListener('mouseup', e => {
-			if (e.button === 1) this.panning = false;
-			if (this.onMouseUp) this.onMouseUp(e);
-		}); 
-
-		/* mouse leave */
-		this.element.addEventListener('mouseleave', e => {
-			this.panning = false;
-		});
-
-		/* mouse wheel */
-		this.element.addEventListener('wheel', e => {
-			if (this.panning) return; // don't zoom and pan simultaneously
-
-			const delta = e.deltaY < 0 ? ZOOM_SPEED : 1/ZOOM_SPEED;
-			const alpha = (1/delta) - 1;
-
-			/* zoom in */
-			this.zoom *= delta;
-			this.zoom = clamp(this.zoom, 1, 1000);
-			this.setTransform();
-
-			/* pan to keep mouse in the same place */
-			const [mouseX, mouseY] = this.screenToDrawingPos(this.mouse.screenPos.x, this.mouse.screenPos.y);
-			this.pan.x += mouseX - this.mouse.drawingPos.x;
-			this.pan.y += mouseY - this.mouse.drawingPos.y;
-			this.setTransform();
-			this.draw();
-		});
-		
-		/* finalize setup */
+		parentElement.appendChild(this.element);
 		this.fillWindow();
 		window.addEventListener('resize', () => this.fillWindow());
-		root.appendChild(this.element);
-	}
-
-	setTransform() {
-		/* clamp pan */
-		const xMax = this.pixelsToUnits(this.element.width) - 1;
-		const yMax = this.pixelsToUnits(this.element.height) - 1;
-		this.pan.x = clamp(this.pan.x, xMax, 0);
-		this.pan.y = clamp(this.pan.y, yMax, 0);
-
-		this.context.setTransform(1, 0, 0, 1, 0, 0);
-		this.context.scale(this.zoom * this.scale, this.zoom * this.scale);
-		this.context.translate(this.pan.x, this.pan.y);
 	}
 
 	fillWindow() {
 		const width = window.innerWidth;
 		const height = window.innerHeight;
-		this.scale = Math.max(width, height);
+		const scale = Math.min(width, height);
 
 		this.element.width = width; this.element.height = height;
-		this.setTransform();
+		this.context.setTransform(0.4*scale, 0, 0, -0.4*scale, 0.5*scale, 0.5*scale);
 
 		this.draw();
 	}
 
-	pixelsToUnits(value) {
-		return value / this.zoom / this.scale;
-	}
-
-	unitsToPixels(value) {
-		return value * this.zoom * this.scale;
-	}
-
-	screenToDrawingPos(xs, ys) {
-		const matrix = this.context.getTransform();
-		matrix.invertSelf();
-
-		/* compute drawing-space position */
-		const x = matrix.a*xs + matrix.b*ys + matrix.e;
-		const y = matrix.c*xs + matrix.d*ys + matrix.f;
-
-		return [ x, y ];
-	}
-
 	draw() {
-		this.context.clearRect(0, 0, 1, 1);
+		this.context.clearRect(-1, -1, 2, 2);
 		if (this.onDraw) this.onDraw(this.context);
 	}
 }
-- 
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