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/node_slider.cpp

@@ -42,8 +42,8 @@ void NodeSliderH::draw()
 void NodeSliderH::set_value(float value)
 {
     m_value = glm::vec2(value) * m_mask;
-    if (on_value_changed)
-        on_value_changed(this, glm::length(m_value));
+    //if (on_value_changed)
+    //    on_value_changed(this, glm::length(m_value));
 }
 
 float NodeSliderH::get_value()