Fix mouse events received for scrollablepage child widgets when mouse is outside scrollablepage area

TODO

@@ -106,3 +106,5 @@ Use global shortcuts desktop portal protocol on wayland when available.
 When support for window capture is enabled on x11 then make sure to not save the window except temporary while the program is open.
 
 Support CJK.
+
+Move ui hover code from ::draw to ::on_event, to properly handle widget event stack.

src/gui/CustomRendererWidget.cpp

@@ -20,7 +20,7 @@ namespace gsr {
         mgl_scissor prev_scissor;
         mgl_window_get_scissor(window.internal_window(), &prev_scissor);
 
-        mgl_scissor new_scissor = {
+        const mgl_scissor new_scissor = {
             mgl_vec2i{(int)draw_pos.x, (int)draw_pos.y},
             mgl_vec2i{(int)size.x, (int)size.y}
         };

src/gui/GsrPage.cpp

@@ -106,7 +106,7 @@ namespace gsr {
         mgl_window_get_scissor(window.internal_window(), &prev_scissor);
 
         const mgl::vec2f inner_size = get_inner_size();
-        mgl_scissor new_scissor = {
+        const mgl_scissor new_scissor = {
             mgl_vec2i{(int)position.x, (int)position.y},
             mgl_vec2i{(int)inner_size.x, (int)inner_size.y}
         };

src/gui/ScrollablePage.cpp

@@ -22,6 +22,18 @@ namespace gsr {
         offset = position + offset + mgl::vec2f(0.0f, scroll_y);
         Widget *selected_widget = selected_child_widget;
 
+        const mgl::vec2f content_size = get_inner_size();
+        const mgl::vec2i scissor_pos(offset.x, offset.y);
+        const mgl::vec2i scissor_size(content_size.x, content_size.y);
+
+        if(event.type == mgl::Event::MouseButtonPressed || event.type == mgl::Event::MouseButtonReleased) {
+            if(!mgl::IntRect(scissor_pos, scissor_pos).contains({event.mouse_button.x, event.mouse_button.y}))
+                return true;
+        } else if(event.type == mgl::Event::MouseMoved) {
+            if(!mgl::IntRect(scissor_pos, scissor_pos).contains({event.mouse_move.x, event.mouse_move.y}))
+                return true;
+        }
+
         if(event.type == mgl::Event::MouseButtonReleased && moving_scrollbar_with_cursor) {
             moving_scrollbar_with_cursor = false;
             remove_widget_as_selected_in_parent();
@@ -79,7 +91,7 @@ namespace gsr {
         mgl_window_get_scissor(window.internal_window(), &prev_scissor);
 
         const mgl::vec2f content_size = get_inner_size();
-        mgl_scissor new_scissor = {
+        const mgl_scissor new_scissor = {
             mgl_vec2i{(int)offset.x, (int)offset.y},
             mgl_vec2i{(int)content_size.x, (int)content_size.y}
         };

src/gui/StaticPage.cpp

@@ -39,7 +39,7 @@ namespace gsr {
         mgl_scissor prev_scissor;
         mgl_window_get_scissor(window.internal_window(), &prev_scissor);
 
-        mgl_scissor new_scissor = {
+        const mgl_scissor new_scissor = {
             mgl_vec2i{(int)draw_pos.x, (int)draw_pos.y},
             mgl_vec2i{(int)size.x, (int)size.y}
         };