add basic color brushing demo

1 files changed, 4 insertions, 0 deletions

diff --git a/src/Canvas.js b/src/Canvas.js
index 7f6404b..6dff7bd 100644
--- a/src/Canvas.js
+++ b/src/Canvas.js
@@ -22,6 +22,8 @@ class Canvas {
 		/* callbacks */
 		this.onDraw = null;
 		this.onMouseMove = null;
+		this.onMouseDown = null;
+		this.onMouseUp = null;
 
 		/* register event listeners */
 
@@ -53,9 +55,11 @@ class Canvas {
 		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 */