ui: scrub hot text from the slider range (#2097)

crates/ui-egui/src/panels/effect_controls.rs

@@ -337,10 +337,7 @@ fn prop_row(
                 ParamUi::Percent => "%",
                 _ => "",
             };
-            let speed = match &prop.ui {
-                ParamUi::Slider { slider_min, slider_max, .. } => ((slider_max - slider_min) / 300.0).clamp(0.001, 50.0),
-                _ => 0.5,
-            };
+            let speed = widgets::slider_scrub_speed(&prop.ui);
             let (vr, nv, _) = widgets::hot_number_at(
                 ui,
                 pos2(vx, cy - 9.0),

crates/ui-egui/src/panels/timeline.rs

@@ -4105,7 +4105,7 @@ fn value_editor(
     match value {
         Value::Scalar(v) => {
             let (min, max, dec, speed) = match &prop.ui {
-                ParamUi::Slider { min, max, decimals, .. } => (*min, *max, *decimals as usize, ((max - min) / 400.0).clamp(0.01, 10.0)),
+                ParamUi::Slider { min, max, decimals, .. } => (*min, *max, *decimals as usize, widgets::slider_scrub_speed(&prop.ui)),
                 ParamUi::Percent => (-1e6, 1e6, 1, 0.5),
                 _ => (-1e9, 1e9, 1, 1.0),
             };

crates/ui-egui/src/widgets.rs

@@ -2,6 +2,8 @@
 
 use egui::{Align2, Color32, Rect, Response, Sense, Stroke, StrokeKind, Ui, pos2, vec2};
 
+use effectcraft_project::ParamUi;
+
 use crate::automation::Registry;
 use crate::icons::{self, Icon};
 use crate::theme::Tokens;
@@ -145,6 +147,16 @@ pub fn proportional_scrub(m: egui::Modifiers) -> bool {
     m.command && m.alt
 }
 
+/// How far one pointer pixel scrubs a hot-text field: the property's slider (soft) range over
+/// 300 px. The Timeline and Effect Controls share this so they cannot drift; a large hard range
+/// only allows typing big values, it must not make dragging coarse (#2097).
+pub fn slider_scrub_speed(ui: &ParamUi) -> f64 {
+    match ui {
+        ParamUi::Slider { slider_min, slider_max, .. } => ((slider_max - slider_min) / 300.0).clamp(0.001, 50.0),
+        _ => 0.5,
+    }
+}
+
 /// [`hot_number_at`] for a whole number (an angle's revolutions): a drag steps it once every
 /// `1 / speed` pixels however slowly the pointer moves (the fractions add up between frames),
 /// and a typed value is truncated. Returns (rect, Some(new value) when changed, drag finished).
@@ -666,6 +678,15 @@ pub(crate) fn constrained(c: &[f64], d: usize, v: f64) -> Vec<f64> {
 mod tests {
     use super::*;
 
+    /// #2097: the drag speed comes from the slider range, not a much wider hard range.
+    #[test]
+    fn slider_scrub_speed_uses_the_slider_range() {
+        let slider = |min, max, slider_min, slider_max| ParamUi::Slider { min, max, slider_min, slider_max, decimals: 1 };
+        assert!((slider_scrub_speed(&slider(0.0, 10_000.0, 0.0, 1_000.0)) - 1_000.0 / 300.0).abs() < 1e-9);
+        assert!((slider_scrub_speed(&slider(0.0, 1.0e9, 0.0, 1.0)) - 1.0 / 300.0).abs() < 1e-9);
+        assert_eq!(slider_scrub_speed(&ParamUi::Number), 0.5);
+    }
+
     /// #488: an inline editor selects its whole text only as it opens. Should it be without the
     /// keyboard for a frame later (an input method, another handler), it takes the keyboard back
     /// with the caret where the user put it instead of selecting everything again, which made