Improved mask also work on erase. Improved shaders for layer opacity, now when drawing doesn't change opacity. Improved layers panel layout to be similar to PS. Added layer blending option and visibility. Added custom icons to checkboxes and fixed the combobox items.

src/canvas.h

@@ -20,6 +20,7 @@ public:
     bool m_alpha_locked = false;
     float m_opacity = 1.f;
     bool m_hightlight = false;
+    bool m_blend_mode = 0;
     std::string m_name;
     int w = 0;
     int h = 0;