feat: add touch event support for mobile canvas interaction

Author: coderomm

apps/collabydraw/canvas-engine/CanvasEngine.ts

@@ -296,6 +296,15 @@ export class CanvasEngine {
     this.canvas.addEventListener("wheel", this.mouseWheelHandler, {
       passive: false,
     });
+    this.canvas.addEventListener("touchstart", this.touchStartHandler, {
+      passive: false,
+    });
+    this.canvas.addEventListener("touchmove", this.touchMoveHandler, {
+      passive: false,
+    });
+    this.canvas.addEventListener("touchend", this.touchEndHandler, {
+      passive: false,
+    });
   }
 
   setTool(tool: ToolType) {
@@ -974,6 +983,38 @@ export class CanvasEngine {
     }
   };
 
+  touchStartHandler = (e: TouchEvent) => {
+    e.preventDefault();
+    const touch = e.touches[0];
+    if (!touch) return;
+
+    const simulatedMouse = new MouseEvent("mousedown", {
+      clientX: touch.clientX,
+      clientY: touch.clientY,
+    });
+
+    this.mouseDownHandler(simulatedMouse);
+  };
+
+  touchMoveHandler = (e: TouchEvent) => {
+    e.preventDefault();
+    const touch = e.touches[0];
+    if (!touch) return;
+
+    const simulatedMouse = new MouseEvent("mousemove", {
+      clientX: touch.clientX,
+      clientY: touch.clientY,
+    });
+
+    this.mouseMoveHandler(simulatedMouse);
+  };
+
+  touchEndHandler = (e: TouchEvent) => {
+    e.preventDefault();
+    const simulatedMouse = new MouseEvent("mouseup", {});
+    this.mouseUpHandler(simulatedMouse);
+  };
+
   private handleTexty(e: MouseEvent) {
     const { x, y } = this.transformPanScale(e.clientX, e.clientY);
 
@@ -1767,6 +1808,9 @@ export class CanvasEngine {
     this.canvas.removeEventListener("mousemove", this.mouseMoveHandler);
     this.canvas.removeEventListener("mouseup", this.mouseUpHandler);
     this.canvas.removeEventListener("wheel", this.mouseWheelHandler);
+    this.canvas.removeEventListener("touchstart", this.touchStartHandler);
+    this.canvas.removeEventListener("touchmove", this.touchMoveHandler);
+    this.canvas.removeEventListener("touchend", this.touchEndHandler);
 
     if (this.socket?.readyState === WebSocket.OPEN) {
       this.socket.send(

apps/collabydraw/components/canvas/CanvasBoard.tsx

@@ -229,8 +229,8 @@ export default function CanvasBoard() {
                     const handleResize = () => {
                         if (canvasRef.current) {
                             const canvas = canvasRef.current;
-                            canvas.width = window.innerWidth;
-                            canvas.height = window.innerHeight;
+                            canvas.width = window.innerWidth || document.documentElement.clientWidth;
+                            canvas.height = window.innerHeight || document.documentElement.clientHeight;
                             engine.handleResize(window.innerWidth, window.innerHeight);
                         }
                     };
@@ -452,7 +452,7 @@ export default function CanvasBoard() {
                 <ScreenLoading />
             )}
 
-            <canvas className={cn("collabydraw collabydraw-canvas", theme === 'dark' ? 'collabydraw-canvas-dark' : '')} ref={canvasRef} />
+            <canvas className={cn("collabydraw collabydraw-canvas touch-none", theme === 'dark' ? 'collabydraw-canvas-dark' : '')} ref={canvasRef} />
         </div >
     )
 };