add cursor visibility mode

src/canvas_modes.h

@@ -82,7 +82,6 @@ class CanvasModePen : public CanvasMode
     float m_zoom_canvas = 1.f;
     float m_zoom_start;
     // resizing the tip
-    bool m_resizing = false;
 public:
     CanvasModePen() { hide_curor = true; m_picking = false; }
     
@@ -91,7 +90,9 @@ public:
     virtual void on_Draw(const glm::mat4& ortho, const glm::mat4& proj, const glm::mat4& camera) override;
     virtual void enter(kCanvasMode prev) override;
     virtual void leave(kCanvasMode next) override;
+    bool m_resizing = false;
     bool m_picking = false;
+    bool m_drawing = false;
     glm::vec2 m_cur_pos;
     bool m_draw_outline = true;
 };