From 7f0276521447c36a3a6026fccc9abdb6e064132c Mon Sep 17 00:00:00 2001 From: Héctor Ramón Jiménez Date: Tue, 18 Aug 2020 04:12:23 +0200 Subject: Draw only visible options in `overlay::Menu` --- graphics/src/overlay/menu.rs | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) (limited to 'graphics/src') diff --git a/graphics/src/overlay/menu.rs b/graphics/src/overlay/menu.rs index a952f065..f42c5e3c 100644 --- a/graphics/src/overlay/menu.rs +++ b/graphics/src/overlay/menu.rs @@ -42,6 +42,7 @@ where &mut self, bounds: Rectangle, cursor_position: Point, + viewport: &Rectangle, options: &[T], hovered_option: Option, padding: u16, @@ -52,16 +53,24 @@ where use std::f32; let is_mouse_over = bounds.contains(cursor_position); + let option_height = text_size as usize + padding as usize * 2; let mut primitives = Vec::new(); - for (i, option) in options.iter().enumerate() { + let offset = viewport.y - bounds.y; + let start = (offset / option_height as f32) as usize; + let end = + ((offset + viewport.height) / option_height as f32).ceil() as usize; + + let visible_options = &options[start..end.min(options.len())]; + + for (i, option) in visible_options.iter().enumerate() { + let i = start + i; let is_selected = hovered_option == Some(i); let bounds = Rectangle { x: bounds.x, - y: bounds.y - + ((text_size as usize + padding as usize * 2) * i) as f32, + y: bounds.y + (option_height * i) as f32, width: bounds.width, height: f32::from(text_size + padding * 2), }; -- cgit