adds support for touch events, enabling touch dragging the canvas

diagrams-demo-gallery/demos/demo-alternative-linking/DefaultState.ts

@@ -1,4 +1,4 @@
-import { MouseEvent } from 'react';
+import { MouseEvent, TouchEvent } from 'react';
 import {
 	SelectingState,
 	State,
@@ -45,6 +45,16 @@ export class DefaultState extends State<DiagramEngine> {
 			})
 		);
 
+		// touch drags the canvas
+		this.registerAction(
+			new Action({
+				type: InputType.TOUCH_START,
+				fire: (event: ActionEvent<TouchEvent>) => {
+					this.transitionWithEvent(new DragCanvasState(), event);
+				}
+			})
+		);
+
 		this.registerAction(
 			new Action({
 				type: InputType.MOUSE_UP,

packages/react-canvas-core/src/core-actions/Action.ts

@@ -1,4 +1,4 @@
-import { MouseEvent, KeyboardEvent, WheelEvent, SyntheticEvent } from 'react';
+import { MouseEvent, KeyboardEvent, WheelEvent, TouchEvent, SyntheticEvent } from 'react';
 import { Toolkit } from '../Toolkit';
 import { CanvasEngine } from '../CanvasEngine';
 import { BaseModel } from '../core-models/BaseModel';
@@ -9,7 +9,10 @@ export enum InputType {
 	MOUSE_MOVE = 'mouse-move',
 	MOUSE_WHEEL = 'mouse-wheel',
 	KEY_DOWN = 'key-down',
-	KEY_UP = 'key-up'
+	KEY_UP = 'key-up',
+	TOUCH_START = 'touch-start',
+	TOUCH_END = 'touch-end',
+	TOUCH_MOVE = 'touch-move'
 }
 
 export interface Mapping {
@@ -19,6 +22,9 @@ export interface Mapping {
 	[InputType.MOUSE_WHEEL]: WheelEvent;
 	[InputType.KEY_DOWN]: KeyboardEvent;
 	[InputType.KEY_UP]: KeyboardEvent;
+	[InputType.TOUCH_START]: TouchEvent;
+	[InputType.TOUCH_END]: TouchEvent;
+	[InputType.TOUCH_MOVE]: TouchEvent;
 }
 
 export interface ActionEvent<Event extends SyntheticEvent = SyntheticEvent, Model extends BaseModel = BaseModel> {

packages/react-canvas-core/src/core-actions/ActionEventBus.ts

@@ -63,7 +63,14 @@ export class ActionEventBus {
 			return this.getActionsForType(InputType.MOUSE_MOVE);
 		} else if (event.type === 'wheel') {
 			return this.getActionsForType(InputType.MOUSE_WHEEL);
+		} else if (event.type === 'touchstart') {
+			return this.getActionsForType(InputType.TOUCH_START);
+		} else if (event.type === 'touchend') {
+			return this.getActionsForType(InputType.TOUCH_END);
+		} else if (event.type === 'touchmove') {
+			return this.getActionsForType(InputType.TOUCH_MOVE);
 		}
+
 		return [];
 	}
 

packages/react-canvas-core/src/core-state/AbstractDisplacementState.ts

@@ -7,7 +7,7 @@ export interface AbstractDisplacementStateEvent {
 	displacementY: number;
 	virtualDisplacementX: number;
 	virtualDisplacementY: number;
-	event: React.MouseEvent;
+	event: React.MouseEvent | React.TouchEvent;
 }
 
 export abstract class AbstractDisplacementState<E extends CanvasEngine = CanvasEngine> extends State<E> {
@@ -63,6 +63,45 @@ export abstract class AbstractDisplacementState<E extends CanvasEngine = CanvasE
 				}
 			})
 		);
+
+		this.registerAction(
+			new Action({
+				type: InputType.TOUCH_START,
+				fire: (actionEvent: ActionEvent<React.TouchEvent>) => {
+					const touch = actionEvent.event.touches[0];
+					this.initialX = touch.clientX;
+					this.initialY = touch.clientY;
+					const rel = this.engine.getRelativePoint(touch.clientX, touch.clientY);
+					this.initialXRelative = rel.x;
+					this.initialYRelative = rel.y;
+				}
+			})
+		);
+		this.registerAction(
+			new Action({
+				type: InputType.TOUCH_MOVE,
+				fire: (actionEvent: ActionEvent<React.TouchEvent>) => {
+					const { event } = actionEvent;
+					const touch = event.touches[0];
+					this.fireMouseMoved({
+						displacementX: touch.clientX - this.initialX,
+						displacementY: touch.clientY - this.initialY,
+						virtualDisplacementX: (touch.clientX - this.initialX) / (this.engine.getModel().getZoomLevel() / 100.0),
+						virtualDisplacementY: (touch.clientY - this.initialY) / (this.engine.getModel().getZoomLevel() / 100.0),
+						event: event
+					});
+				}
+			})
+		);
+		this.registerAction(
+			new Action({
+				type: InputType.TOUCH_END,
+				fire: (event: ActionEvent<React.TouchEvent>) => {
+					// when the mouse if up, we eject this state
+					this.eject();
+				}
+			})
+		);
 	}
 
 	abstract fireMouseMoved(event: AbstractDisplacementStateEvent);

packages/react-canvas-core/src/entities/canvas/CanvasWidget.tsx

@@ -90,6 +90,15 @@ export class CanvasWidget extends React.Component<DiagramProps> {
 				}}
 				onMouseMove={(event) => {
 					this.props.engine.getActionEventBus().fireAction({ event });
+				}}
+				onTouchStart={(event) => {
+					this.props.engine.getActionEventBus().fireAction({ event });
+				}}
+				onTouchEnd={(event) => {
+					this.props.engine.getActionEventBus().fireAction({ event });
+				}}
+				onTouchMove={(event) => {
+					this.props.engine.getActionEventBus().fireAction({ event });
 				}}>
 				{model.getLayers().map((layer) => {
 					return (

packages/react-canvas-core/src/entities/selection/SelectionBoxWidget.tsx

@@ -16,6 +16,9 @@ namespace S {
 export class SelectionBoxWidget extends React.Component<SelectionBoxWidgetProps> {
 	render() {
 		const { rect } = this.props;
+
+		if (!rect) return;
+
 		return (
 			<S.Container
 				style={{

packages/react-canvas-core/src/states/DefaultState.ts

@@ -1,6 +1,6 @@
 import { State } from '../core-state/State';
 import { Action, ActionEvent, InputType } from '../core-actions/Action';
-import { MouseEvent } from 'react';
+import { MouseEvent, TouchEvent } from 'react';
 import { DragCanvasState } from './DragCanvasState';
 import { SelectingState } from './SelectingState';
 import { MoveItemsState } from './MoveItemsState';
@@ -28,5 +28,15 @@ export class DefaultState extends State {
 				}
 			})
 		);
+
+		// touch drags the canvas
+		this.registerAction(
+			new Action({
+				type: InputType.TOUCH_START,
+				fire: (event: ActionEvent<TouchEvent>) => {
+					this.transitionWithEvent(new DragCanvasState(), event);
+				}
+			})
+		);
 	}
 }

packages/react-canvas-core/src/states/SelectionBoxState.ts

@@ -1,7 +1,8 @@
+import { MouseEvent, TouchEvent } from 'react';
 import { AbstractDisplacementState, AbstractDisplacementStateEvent } from '../core-state/AbstractDisplacementState';
 import { State } from '../core-state/State';
 import { SelectionLayerModel } from '../entities/selection/SelectionLayerModel';
-import { Rectangle } from '@projectstorm/geometry';
+import { Point, Rectangle } from '@projectstorm/geometry';
 import { ModelGeometryInterface } from '../core/ModelGeometryInterface';
 
 export class SelectionBoxState extends AbstractDisplacementState {
@@ -26,7 +27,13 @@ export class SelectionBoxState extends AbstractDisplacementState {
 	}
 
 	getBoxDimensions(event: AbstractDisplacementStateEvent): ClientRect {
-		const rel = this.engine.getRelativePoint(event.event.clientX, event.event.clientY);
+		let rel: Point;
+		if (event.event instanceof MouseEvent) {
+			rel = this.engine.getRelativePoint(event.event.clientX, event.event.clientY);
+		} else if (event.event instanceof TouchEvent) {
+			const touch = event.event.touches[0];
+			rel = this.engine.getRelativePoint(touch.clientX, touch.clientY);
+		}
 
 		return {
 			left: rel.x > this.initialXRelative ? this.initialXRelative : rel.x,

packages/react-diagrams-core/src/states/DefaultDiagramState.ts

@@ -1,4 +1,4 @@
-import { MouseEvent } from 'react';
+import { MouseEvent, TouchEvent } from 'react';
 import {
 	SelectingState,
 	State,
@@ -48,5 +48,15 @@ export class DefaultDiagramState extends State<DiagramEngine> {
 				}
 			})
 		);
+
+		// touch drags the canvas
+		this.registerAction(
+			new Action({
+				type: InputType.TOUCH_START,
+				fire: (event: ActionEvent<TouchEvent>) => {
+					this.transitionWithEvent(this.dragCanvas, event);
+				}
+			})
+		);
 	}
 }