implementing separate pen/erase brush settings

engine/canvas_modes.h

@@ -1,6 +1,7 @@
 #pragma once
 #include "event.h"
 #include "shape.h"
+#include "brush.h"
 
 NS_START
 class Canvas;
@@ -16,6 +17,7 @@ public:
     virtual void on_GestureEvent(GestureEvent* ge) {}
     virtual void on_Draw(const glm::mat4& ortho, const glm::mat4& proj, const glm::mat4& camera) {}
     virtual void init() {}
+    virtual void enter() {}
     virtual void leave() {}
 };
 
@@ -39,8 +41,11 @@ class CanvasModePen : public CanvasMode
     float m_camera_fov;
     float m_zoom_canvas = 1.f;
     float m_zoom_start;
+    ui::Brush m_brush;
 public:
     virtual void on_MouseEvent(MouseEvent* me, glm::vec2& loc) override;
+    virtual void enter() override;
+    virtual void leave() override;
     bool m_picking = false;
 };