LR-BEHAV-BG-TASKS: one whole-percent rule for the bar text and its announced value

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

@@ -142,12 +142,12 @@ pub fn detail_toggle(app: &mut LightcraftApp, ui: &mut egui::Ui, id: PhotoId, on
 }
 
 /// The bar under the Denoise slider while a photo's picture is made: at most 240 px wide, and
-/// sweeping while the number of tiles is not known yet. The percentage is floored, as the bar's
-/// accessible value is (and the SAM bar's text): 100 % only once done.
+/// sweeping while the number of tiles is not known yet. The percentage is `progress::percent`, as the
+/// bar's accessible value is: 100 % only once done.
 pub(crate) fn detail_bar(ui: &mut egui::Ui, done: u64, total: u64) -> egui::Response {
     let fraction = crate::progress::fraction_of(done, total);
     let text = match fraction {
-        Some(f) => tr_format!("Making the denoised picture… {}%", (f * 100.0).floor() as u32),
+        Some(f) => tr_format!("Making the denoised picture… {}%", crate::progress::percent(f)),
         None => tr("Starting…").to_string(),
     };
     crate::progress::Progress::new(fraction).label(text).width(ui.available_width().min(240.0)).widget("denoise:progress").show(ui)

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

@@ -766,7 +766,7 @@ pub(crate) fn start_describe(app: &mut LightcraftApp, op: &str) {
 pub(crate) fn sam_download_bar(ui: &mut egui::Ui, done: u64, total: u64, width: f32) -> egui::Response {
     let fraction = crate::progress::fraction_of(done, total);
     let label = match fraction {
-        Some(f) => format!("SAM 3: {} %", (f64::from(f) * 100.0).floor()),
+        Some(f) => format!("SAM 3: {} %", crate::progress::percent(f)),
         None => "SAM 3".to_string(),
     };
     crate::progress::Progress::new(fraction).label(label).width(width).widget("maskSamProgress").show(ui)

crates/ui-egui/src/progress.rs

@@ -45,6 +45,15 @@ pub fn fraction_of(done: u64, total: u64) -> Option<f32> {
     (total > 0).then(|| clamp_fraction(done as f32 / total as f32))
 }
 
+/// The whole percent a bar says for `fraction`: rounded down, so 100 comes only at exactly 1.0, but
+/// with a little slack so a fraction that is exact in decimals (53 of 100, held as 0.52999997)
+/// still says 53. A bar's text and its accessible value both come from here, so they agree.
+pub fn percent(fraction: f32) -> u32 {
+    let f = clamp_fraction(fraction);
+    let whole = (f64::from(f) * 100.0 + 1e-3).floor() as u32;
+    if f < 1.0 { whole.min(99) } else { 100 }
+}
+
 /// A progress bar, built and then shown with [`Progress::show`].
 #[derive(Clone, Debug)]
 pub struct Progress {
@@ -103,7 +112,7 @@ impl Progress {
                 Some(l) => egui::WidgetInfo::labeled(egui::WidgetType::ProgressIndicator, ui.is_enabled(), l),
                 None => egui::WidgetInfo::new(egui::WidgetType::ProgressIndicator),
             };
-            info.value = self.fraction.map(|f| f64::from(f * 100.0).floor());
+            info.value = self.fraction.map(|f| f64::from(percent(f)));
             info
         });
         if let Some(w) = &self.widget {

crates/ui-egui/src/tests_progress.rs

@@ -240,13 +240,27 @@ fn the_denoise_bars_keep_their_widths_in_a_wide_container() {
 
 #[test]
 fn the_denoise_bar_label_and_its_accessible_value_agree() {
-    // 3 of 7 is 42.86 %: the number drawn on the bar is the one announced
-    let (nodes, _, _) = frames(Vec::new(), |ui| {
-        crate::panels::denoise::detail_bar(ui, 3, 7);
-    });
-    let bar = nodes.iter().find(|n| n.role == "ProgressIndicator").unwrap_or_else(|| panic!("{nodes:?}"));
-    let shown: f64 = bar.label.rsplit(' ').next().unwrap().trim_end_matches('%').parse().unwrap();
-    assert_eq!(bar.value, Some(shown), "{bar:?}");
+    // the number drawn on the bar is the one announced, and exact decimals stay exact
+    for (done, total, says) in
+        [(3, 7, 42.0), (53, 100, 53.0), (59, 100, 59.0), (29, 100, 29.0), (99, 100, 99.0), (100, 100, 100.0), (999, 1000, 99.0)]
+    {
+        let (nodes, _, _) = frames(Vec::new(), |ui| {
+            crate::panels::denoise::detail_bar(ui, done, total);
+        });
+        let bar = nodes.iter().find(|n| n.role == "ProgressIndicator").unwrap_or_else(|| panic!("{nodes:?}"));
+        let shown: f64 = bar.label.rsplit(' ').next().unwrap().trim_end_matches('%').parse().unwrap();
+        assert_eq!((shown, bar.value), (says, Some(says)), "{done}/{total}: {bar:?}");
+    }
+}
+
+#[test]
+fn the_sam_bar_text_and_its_accessible_value_agree() {
+    for (done, total, says) in [(53, 100, 53.0), (59, 100, 59.0), (29, 100, 29.0), (999, 1000, 99.0), (100, 100, 100.0)] {
+        let (nodes, _, _) = frames(Vec::new(), |ui| crate::panels::masking::sam_download_bar(ui, done, total, 200.0).rect.width());
+        let bar = nodes.iter().find(|n| n.role == "ProgressIndicator").unwrap_or_else(|| panic!("{nodes:?}"));
+        assert_eq!(bar.label, format!("SAM 3: {says} %"), "{done}/{total}");
+        assert_eq!(bar.value, Some(says), "{done}/{total}");
+    }
 }
 
 #[test]