From 94a8e64a4efd77d6e98b57fe4691eccf981f8223 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jochen=20G=C3=B6rtler?= <me@jgoertler.com>
Date: Fri, 13 Dec 2024 11:09:11 +0100
Subject: [PATCH] Implement level-of-detail on text labels

---
 crates/viewer/re_view_graph/src/ui/draw.rs | 28 ++++++++++++++++------
 1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/crates/viewer/re_view_graph/src/ui/draw.rs b/crates/viewer/re_view_graph/src/ui/draw.rs
index df47b3307b99f..989f63d8f3c11 100644
--- a/crates/viewer/re_view_graph/src/ui/draw.rs
+++ b/crates/viewer/re_view_graph/src/ui/draw.rs
@@ -35,6 +35,7 @@ impl DrawableLabel {
 }
 
 pub struct TextLabel {
+    color: Option<Color32>,
     frame: Frame,
     galley: Arc<Galley>,
 }
@@ -52,7 +53,7 @@ pub enum LevelOfDetail {
 
 impl LevelOfDetail {
     pub fn from_scaling(zoom: f32) -> Self {
-        if zoom < 0.25 {
+        if zoom < 0.20 {
             Self::Low
         } else {
             Self::Full
@@ -64,7 +65,7 @@ impl DrawableLabel {
     pub fn size(&self) -> Vec2 {
         match self {
             Self::Circle(CircleLabel { radius, .. }) => Vec2::splat(radius * 2.0),
-            Self::Text(TextLabel { galley, frame }) => {
+            Self::Text(TextLabel { galley, frame, .. }) => {
                 frame.inner_margin.sum() + galley.size() + Vec2::splat(frame.stroke.width * 2.0)
             }
         }
@@ -98,7 +99,11 @@ impl DrawableLabel {
             .fill(ui.style().visuals.widgets.noninteractive.bg_fill)
             .stroke(Stroke::new(1.0, ui.style().visuals.text_color()));
 
-        Self::Text(TextLabel { frame, galley })
+        Self::Text(TextLabel {
+            frame,
+            galley,
+            color,
+        })
     }
 }
 
@@ -131,7 +136,7 @@ fn draw_circle_label(
 }
 
 fn draw_text_label(ui: &mut Ui, label: &TextLabel, highlight: InteractionHighlight) -> Response {
-    let TextLabel { galley, frame } = label;
+    let TextLabel { galley, frame, .. } = label;
     let visuals = &ui.style().visuals;
 
     let bg = match highlight.hover {
@@ -154,7 +159,11 @@ fn draw_text_label(ui: &mut Ui, label: &TextLabel, highlight: InteractionHighlig
 }
 
 fn draw_rect_label(ui: &mut Ui, label: &TextLabel, highlight: InteractionHighlight) -> Response {
-    let TextLabel { galley, frame } = label;
+    let TextLabel {
+        galley,
+        frame,
+        color,
+    } = label;
     let visuals = &ui.style().visuals;
 
     let bg = match highlight.hover {
@@ -167,12 +176,17 @@ fn draw_rect_label(ui: &mut Ui, label: &TextLabel, highlight: InteractionHighlig
         _ => Stroke::new(1.0, visuals.text_color()),
     };
 
+    // We use `gamma` to correct for the fact that text is not completely solid.
+    let fill_color = color
+        .unwrap_or_else(|| visuals.text_color())
+        .gamma_multiply(0.5);
+
     frame
         .stroke(stroke)
         .fill(bg)
         .show(ui, |ui| {
-            let (resp, painter) = ui.allocate_painter(galley.rect.size(), Sense::click());
-            painter.rect_filled(galley.rect, 0.0, Color32::RED);
+            let (resp, painter) = ui.allocate_painter(galley.rect.size(), Sense::hover());
+            painter.rect_filled(resp.rect, 0.0, fill_color);
             resp
         })
         .inner