Implements improvements to the zooming behavior

i18n/ar.yaml

@@ -59,6 +59,8 @@ settings:
   cursor_tracking: "تتبع المؤشر"
   cursor_tracking_desc: "إبقاء المؤشر في المنتصف أثناء التمرير"
   window: "النافذة:"
+  scroll_to_zoom: "التمرير للتكبير"
+  scroll_to_zoom_desc: "عجلة الماوس تكبر المخطط مباشرة بدلاً من الإزاحة"
   field_names: "أسماء الحقول"
   field_normalization: "توحيد الحقول"
   field_normalization_desc: "توحيد أسماء القنوات عبر أنواع ECU"

i18n/bn.yaml

@@ -59,6 +59,8 @@ settings:
   cursor_tracking: "কার্সর ট্র্যাকিং"
   cursor_tracking_desc: "স্ক্রাবিংয়ের সময় কার্সর কেন্দ্রে রাখুন"
   window: "উইন্ডো:"
+  scroll_to_zoom: "স্ক্রল করে জুম করুন"
+  scroll_to_zoom_desc: "মাউস হুইল সরাসরি চার্টকে জুম করে প্যানিং এর পরিবর্তে"
   field_names: "ফিল্ড নাম"
   field_normalization: "ফিল্ড নরমালাইজেশন"
   field_normalization_desc: "ECU টাইপ জুড়ে চ্যানেল নাম মানসম্মত করুন"

i18n/de.yaml

@@ -59,6 +59,8 @@ settings:
   cursor_tracking: "Cursor-Verfolgung"
   cursor_tracking_desc: "Cursor beim Scrubben zentriert halten"
   window: "Fenster:"
+  scroll_to_zoom: "Scrollen zum Zoomen"
+  scroll_to_zoom_desc: "Mausrad zoomt direkt in das Diagramm, anstatt es zu verschieben"
   field_names: "Feldnamen"
   field_normalization: "Feldnormalisierung"
   field_normalization_desc: "Kanalnamen über ECU-Typen hinweg standardisieren"

i18n/en.yaml

@@ -59,6 +59,8 @@ settings:
   cursor_tracking: "Cursor Tracking"
   cursor_tracking_desc: "Keep cursor centered while scrubbing"
   window: "Window:"
+  scroll_to_zoom: "Scroll to Zoom"
+  scroll_to_zoom_desc: "Scroll wheel zooms the chart directly instead of panning"
   field_names: "Field Names"
   field_normalization: "Field Normalization"
   field_normalization_desc: "Standardize channel names across ECU types"

i18n/es.yaml

@@ -59,6 +59,8 @@ settings:
   cursor_tracking: "Seguimiento del Cursor"
   cursor_tracking_desc: "Mantener el cursor centrado al desplazar"
   window: "Ventana:"
+  scroll_to_zoom: "Desplazar para Zoom"
+  scroll_to_zoom_desc: "La rueda de desplazamiento amplía el gráfico directamente en lugar de desplazarse"
   field_names: "Nombres de Campos"
   field_normalization: "Normalizacion de Campos"
   field_normalization_desc: "Estandarizar nombres de canales entre tipos de ECU"

i18n/fr.yaml

@@ -59,6 +59,8 @@ settings:
   cursor_tracking: "Suivi du curseur"
   cursor_tracking_desc: "Garder le curseur centre pendant le defilement"
   window: "Fenetre :"
+  scroll_to_zoom: "Scroll pour Zoomer"
+  scroll_to_zoom_desc: "La molette de la souris zoome le graphique directement au lieu de faire defiler"
   field_names: "Noms des champs"
   field_normalization: "Normalisation des champs"
   field_normalization_desc: "Standardiser les noms de canaux entre les types d'ECU"

i18n/hi.yaml

@@ -59,6 +59,8 @@ settings:
   cursor_tracking: "कर्सर ट्रैकिंग"
   cursor_tracking_desc: "स्क्रबिंग के दौरान कर्सर को केंद्रित रखें"
   window: "विंडो:"
+  scroll_to_zoom: "स्क्रॉल करके ज़ूम करें"
+  scroll_to_zoom_desc: "माउस व्हील सीधे चार्ट को ज़ूम करता है, पैन करने के बजाय"
   field_names: "फ़ील्ड नाम"
   field_normalization: "फ़ील्ड नॉर्मलाइज़ेशन"
   field_normalization_desc: "ECU प्रकारों में चैनल नामों को मानकीकृत करें"

i18n/id.yaml

@@ -59,6 +59,8 @@ settings:
   cursor_tracking: "Pelacakan Kursor"
   cursor_tracking_desc: "Pertahankan kursor di tengah saat menggulir"
   window: "Jendela:"
+  scroll_to_zoom: "Gulir untuk Zoom"
+  scroll_to_zoom_desc: "Roda mouse memperbesar grafik secara langsung daripada menggeser"
   field_names: "Nama Field"
   field_normalization: "Normalisasi Field"
   field_normalization_desc: "Standarisasi nama kanal antar jenis ECU"

i18n/it.yaml

@@ -59,6 +59,8 @@ settings:
   cursor_tracking: "Tracciamento Cursore"
   cursor_tracking_desc: "Mantieni il cursore centrato durante lo scorrimento"
   window: "Finestra:"
+  scroll_to_zoom: "Scroll per Zoom"
+  scroll_to_zoom_desc: "La rotella del mouse ingrandisce il grafico direttamente invece di scorrere"
   field_names: "Nomi dei Campi"
   field_normalization: "Normalizzazione Campi"
   field_normalization_desc: "Standardizza i nomi dei canali tra diversi tipi di ECU"

i18n/ja.yaml

@@ -59,6 +59,8 @@ settings:
   cursor_tracking: "カーソル追従"
   cursor_tracking_desc: "スクラブ中にカーソルを中央に保持"
   window: "ウィンドウ:"
+  scroll_to_zoom: "スクロールしてズーム"
+  scroll_to_zoom_desc: "マウスホイールでチャートを直接ズームします（パンの代わりに）"
   field_names: "フィールド名"
   field_normalization: "フィールド正規化"
   field_normalization_desc: "ECUタイプ間でチャンネル名を標準化"

i18n/pt-BR.yaml

@@ -59,6 +59,8 @@ settings:
   cursor_tracking: "Rastreamento do Cursor"
   cursor_tracking_desc: "Manter o cursor centralizado durante a navegação"
   window: "Janela:"
+  scroll_to_zoom: "Scroll para Ampliar"
+  scroll_to_zoom_desc: "A roda do mouse amplia o gráfico diretamente em vez de fazer pan"
   field_names: "Nomes dos Campos"
   field_normalization: "Normalização de Campos"
   field_normalization_desc: "Padronizar nomes de canais entre tipos de ECU"

i18n/pt-PT.yaml

@@ -59,6 +59,8 @@ settings:
   cursor_tracking: "Seguimento do Cursor"
   cursor_tracking_desc: "Manter o cursor centrado durante a navegação"
   window: "Janela:"
+  scroll_to_zoom: "Scroll para Ampliação"
+  scroll_to_zoom_desc: "A roda do rato amplia o gráfico diretamente em vez de fazer pan"
   field_names: "Nomes dos Campos"
   field_normalization: "Normalização de Campos"
   field_normalization_desc: "Uniformizar nomes de canais entre tipos de ECU"

i18n/ru.yaml

@@ -59,6 +59,8 @@ settings:
   cursor_tracking: "Отслеживание курсора"
   cursor_tracking_desc: "Удерживать курсор в центре при прокрутке"
   window: "Окно:"
+  scroll_to_zoom: "Прокрутка для увеличения"
+  scroll_to_zoom_desc: "Колесико мыши увеличивает график напрямую вместо панорамирования"
   field_names: "Имена полей"
   field_normalization: "Нормализация полей"
   field_normalization_desc: "Стандартизировать имена каналов для разных типов ECU"

i18n/ur.yaml

@@ -60,6 +60,8 @@ settings:
   cursor_tracking: "کرسر ٹریکنگ"
   cursor_tracking_desc: "سکربنگ کے دوران کرسر کو مرکز میں رکھیں"
   window: "ونڈو:"
+  scroll_to_zoom: "سکرول کریں تاکہ تقریب ہو"
+  scroll_to_zoom_desc: "ماؤس وہیل براہ راست چارٹ کو بڑھاتا ہے بجائے پیننگ کے"
   field_names: "فیلڈ کے نام"
   field_normalization: "فیلڈ نارملائزیشن"
   field_normalization_desc: "ECU اقسام میں چینل ناموں کو معیاری بنائیں"

i18n/zh-CN.yaml

@@ -59,6 +59,8 @@ settings:
   cursor_tracking: "光标跟踪"
   cursor_tracking_desc: "拖动时保持光标居中"
   window: "窗口:"
+  scroll_to_zoom: "滚动以缩放"
+  scroll_to_zoom_desc: "鼠标滚轮直接缩放图表，而不是平移"
   field_names: "字段名称"
   field_normalization: "字段标准化"
   field_normalization_desc: "统一不同 ECU 类型的通道名称"

src/app.rs

@@ -78,6 +78,8 @@ pub struct UltraLogApp {
     // === Chart View State ===
     /// Initial view window in seconds (shown before user interacts with chart)
     pub(crate) initial_view_seconds: f64,
+    /// When true, scroll wheel zooms chart directly instead of panning
+    pub(crate) scroll_to_zoom: bool,
     // === Unit Preferences ===
     /// User preferences for display units
     pub(crate) unit_preferences: UnitPreferences,
@@ -176,6 +178,7 @@ impl Default for UltraLogApp {
             color_blind_mode: false,
             field_normalization: true, // Enabled by default for better readability
             initial_view_seconds: 60.0, // Start with 60 second view
+            scroll_to_zoom: false,
             unit_preferences: UnitPreferences::default(),
             font_scale: FontScale::default(),
             custom_normalizations: HashMap::new(),
@@ -254,6 +257,7 @@ impl UltraLogApp {
         Self {
             user_settings: user_settings.clone(),
             language: user_settings.language,
+            scroll_to_zoom: user_settings.scroll_to_zoom,
             ..Self::default()
         }
     }
@@ -1356,6 +1360,12 @@ impl UltraLogApp {
         }
     }
 
+    /// Stop playback and reset the frame timer
+    fn stop_playback(&mut self) {
+        self.is_playing = false;
+        self.last_frame_time = None;
+    }
+
     // ========================================================================
     // Keyboard Shortcuts
     // ========================================================================
@@ -1433,6 +1443,66 @@ impl UltraLogApp {
                 return;
             }
 
+            // Arrow Left - step one record backward (Shift = 10 records)
+            if i.key_pressed(egui::Key::ArrowLeft) {
+                self.stop_playback();
+                if let Some(tab_idx) = self.active_tab {
+                    let file_index = self.tabs[tab_idx].file_index;
+                    if file_index < self.files.len() {
+                        let times = self.files[file_index].log.get_times_as_f64();
+                        if !times.is_empty() {
+                            let current = self.get_cursor_record().unwrap_or(0);
+                            let step = if shift { 10 } else { 1 };
+                            let new_record = current.saturating_sub(step);
+                            self.set_cursor_time(Some(times[new_record]));
+                            self.set_cursor_record(Some(new_record));
+                        }
+                    }
+                }
+                return;
+            }
+
+            // Arrow Right - step one record forward (Shift = 10 records)
+            if i.key_pressed(egui::Key::ArrowRight) {
+                self.stop_playback();
+                if let Some(tab_idx) = self.active_tab {
+                    let file_index = self.tabs[tab_idx].file_index;
+                    if file_index < self.files.len() {
+                        let times = self.files[file_index].log.get_times_as_f64();
+                        if !times.is_empty() {
+                            let current = self.get_cursor_record().unwrap_or(0);
+                            let step = if shift { 10 } else { 1 };
+                            let new_record = (current + step).min(times.len() - 1);
+                            self.set_cursor_time(Some(times[new_record]));
+                            self.set_cursor_record(Some(new_record));
+                        }
+                    }
+                }
+                return;
+            }
+
+            // Home - jump to start of log
+            if i.key_pressed(egui::Key::Home) {
+                self.stop_playback();
+                if let Some((min, _)) = self.get_time_range() {
+                    self.set_cursor_time(Some(min));
+                    let record = self.find_record_at_time(min);
+                    self.set_cursor_record(record);
+                }
+                return;
+            }
+
+            // End - jump to end of log
+            if i.key_pressed(egui::Key::End) {
+                self.stop_playback();
+                if let Some((_, max)) = self.get_time_range() {
+                    self.set_cursor_time(Some(max));
+                    let record = self.find_record_at_time(max);
+                    self.set_cursor_record(record);
+                }
+                return;
+            }
+
             // Spacebar to toggle play/pause
             if i.key_pressed(egui::Key::Space) {
                 self.is_playing = !self.is_playing;

src/settings.rs

@@ -16,6 +16,9 @@ pub struct UserSettings {
     /// Selected language
     #[serde(default)]
     pub language: Language,
+    /// When true, scroll wheel zooms chart directly instead of panning
+    #[serde(default)]
+    pub scroll_to_zoom: bool,
 }
 
 fn default_version() -> u32 {
@@ -27,6 +30,7 @@ impl Default for UserSettings {
         Self {
             version: 1,
             language: Language::default(),
+            scroll_to_zoom: false,
         }
     }
 }

src/ui/chart.rs

@@ -98,19 +98,30 @@ impl UltraLogApp {
         let chart_interacted = self.get_chart_interacted();
         let initial_view_seconds = self.initial_view_seconds;
         let jump_to_time = self.get_jump_to_time();
+        let scroll_to_zoom = self.scroll_to_zoom;
+
+        // Read scroll input before plot consumes it (for scroll-to-zoom mode)
+        let scroll_delta_y = if scroll_to_zoom && !cursor_tracking {
+            ui.input(|i| i.smooth_scroll_delta.y)
+        } else {
+            0.0
+        };
 
         // Fixed Y bounds for normalized data (0-1 with small padding)
         const Y_MIN: f64 = -0.05;
         const Y_MAX: f64 = 1.05;
+        /// Sensitivity multiplier for scroll-to-zoom (higher = faster zoom per scroll tick)
+        const SCROLL_ZOOM_SENSITIVITY: f64 = 0.003;
 
         // Build the plot - X-axis zoom only, Y fixed
+        // When scroll_to_zoom is enabled, disable scroll-to-pan so we handle scroll as zoom
         let plot = Plot::new("log_chart")
             .legend(egui_plot::Legend::default())
             .y_axis_label("") // Hide Y axis label since values are normalized
             .show_axes([true, false]) // Show X axis (time), hide Y axis (normalized 0-1)
             .allow_zoom([true, false]) // Only allow X-axis zoom
             .allow_drag([!cursor_tracking, false]) // Only allow X-axis drag, never Y
-            .allow_scroll([!cursor_tracking, false]); // Only allow X-axis scroll, never Y
+            .allow_scroll([!cursor_tracking && !scroll_to_zoom, false]); // Disable scroll-pan when scroll-to-zoom enabled
 
         let response = plot.show(ui, |plot_ui| {
             // Get current bounds
@@ -170,6 +181,40 @@ impl UltraLogApp {
                 }
             }
 
+            // Apply scroll-to-zoom: use scroll delta to zoom centered on pointer
+            if scroll_to_zoom && scroll_delta_y.abs() > 0.1 {
+                if let Some((min_t, max_t)) = time_range {
+                    let zoom_factor =
+                        (1.0 - scroll_delta_y as f64 * SCROLL_ZOOM_SENSITIVITY).clamp(0.8, 1.25);
+                    let width = x_max - x_min;
+                    let new_width = (width * zoom_factor).clamp(0.01, max_t - min_t);
+
+                    // Zoom around pointer position if hovering, otherwise center
+                    let center = plot_ui
+                        .pointer_coordinate()
+                        .map(|p| p.x.clamp(x_min, x_max))
+                        .unwrap_or((x_min + x_max) / 2.0);
+                    let ratio = if width > 0.0 {
+                        (center - x_min) / width
+                    } else {
+                        0.5
+                    };
+
+                    x_min = center - new_width * ratio;
+                    x_max = center + new_width * (1.0 - ratio);
+
+                    // Clamp to data range
+                    if x_min < min_t {
+                        x_min = min_t;
+                        x_max = (min_t + new_width).min(max_t);
+                    }
+                    if x_max > max_t {
+                        x_max = max_t;
+                        x_min = (max_t - new_width).max(min_t);
+                    }
+                }
+            }
+
             // Always enforce bounds: X clamped to data, Y fixed to normalized range
             let new_bounds = PlotBounds::from_min_max([x_min, Y_MIN], [x_max, Y_MAX]);
             plot_ui.set_plot_bounds(new_bounds);
@@ -224,6 +269,7 @@ impl UltraLogApp {
             || response.response.drag_started()
             || ui.input(|i| i.zoom_delta() != 1.0)
             || ui.input(|i| i.smooth_scroll_delta.x != 0.0)
+            || (scroll_to_zoom && scroll_delta_y.abs() > 0.1)
         {
             self.set_chart_interacted(true);
         }

src/ui/settings_panel.rs

@@ -159,6 +159,26 @@ impl UltraLogApp {
                     );
                 });
             }
+
+            ui.add_space(8.0);
+
+            // Scroll to zoom
+            let old_scroll_to_zoom = self.scroll_to_zoom;
+            ui.checkbox(
+                &mut self.scroll_to_zoom,
+                egui::RichText::new(t!("settings.scroll_to_zoom")).size(font_14),
+            );
+            ui.label(
+                egui::RichText::new(t!("settings.scroll_to_zoom_desc"))
+                    .size(font_12)
+                    .color(egui::Color32::GRAY),
+            );
+            if self.scroll_to_zoom != old_scroll_to_zoom {
+                self.user_settings.scroll_to_zoom = self.scroll_to_zoom;
+                if let Err(e) = self.user_settings.save() {
+                    self.show_toast_error(&t!("toast.failed_to_save", error = e));
+                }
+            }
         });
     }
 

tests/core/settings_tests.rs

@@ -110,6 +110,7 @@ fn test_settings_roundtrip() {
     let original = UserSettings {
         version: 1,
         language: Language::Spanish,
+        scroll_to_zoom: false,
     };
 
     let json = serde_json::to_string(&original).unwrap();
@@ -125,6 +126,7 @@ fn test_settings_roundtrip_all_languages() {
         let settings = UserSettings {
             version: 1,
             language: *lang,
+            scroll_to_zoom: false,
         };
 
         let json = serde_json::to_string(&settings).unwrap();
@@ -223,6 +225,7 @@ fn test_settings_clone() {
     let original = UserSettings {
         version: 1,
         language: Language::Spanish,
+        scroll_to_zoom: false,
     };
 
     let cloned = original.clone();