only render avatars if visible

src/chat_gui/contact_list.cpp

@@ -95,6 +95,12 @@ void renderAvatar(
 	const Contact3Handle c,
 	ImVec2 box
 ) {
+	// deploy dummy of same size and check visibility
+	const auto orig_curser_pos = ImGui::GetCursorPos();
+	ImGui::Dummy(box);
+	if (ImGui::IsItemVisible()) {
+		ImGui::SetCursorPos(orig_curser_pos); // reset for actual img
+
 		ImVec4 color_current = th.getColor<ThemeCol_Contact::avatar_offline>();
 		if (c.all_of<Contact::Components::ConnectionState>()) {
 			const auto c_state = c.get<Contact::Components::ConnectionState>().state;
@@ -105,14 +111,6 @@ void renderAvatar(
 			}
 		}
 
-	// icon pos
-	auto p0 = ImGui::GetCursorScreenPos();
-	p0.x += box.x * 0.5f;
-	p0.y += box.y * 0.5f;
-	auto p1_o = box;
-	p1_o.x *= 0.5f;
-	p1_o.y *= 0.5f;
-
 		// avatar
 		const auto [id, width, height] = contact_tc.get(c);
 		ImGui::Image(
@@ -123,7 +121,7 @@ void renderAvatar(
 			{1, 1, 1, 1},
 			color_current
 		);
-
+	}
 }
 
 bool renderContactBig(