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Fix piano roll scrolling

This commit is contained in:
Skyler Lehmkuhl 2026-02-14 21:43:00 -05:00
parent 068715c0fa
commit 04a7f35b84
1 changed files with 100 additions and 54 deletions
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154
lightningbeam-ui/lightningbeam-editor/src/panes/piano_roll.rs
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@ -136,6 +136,14 @@ impl PianoRollPane {
self.viewport_start_time + ((x - grid_rect.min.x) / self.pixels_per_second) as f64
}
fn apply_zoom_at_point(&mut self, zoom_delta: f32, mouse_x: f32, grid_rect: Rect) {
let time_at_mouse = self.x_to_time(mouse_x, grid_rect);
self.pixels_per_second = (self.pixels_per_second * (1.0 + zoom_delta)).clamp(20.0, 2000.0);
let new_mouse_x = self.time_to_x(time_at_mouse, grid_rect);
let time_delta = (new_mouse_x - mouse_x) / self.pixels_per_second;
self.viewport_start_time = (self.viewport_start_time + time_delta as f64).max(0.0);
}
fn note_to_y(&self, note: u8, rect: Rect) -> f32 {
let note_index = (MAX_NOTE - note) as f32;
rect.min.y + note_index * self.note_height - self.scroll_y
@ -261,14 +269,10 @@ impl PianoRollPane {
// Handle input before rendering
self.handle_input(ui, grid_rect, keyboard_rect, shared, &clip_data);
// Auto-scroll during playback
// Auto-scroll during playback: pin playhead to center of viewport
if *shared.is_playing && self.auto_scroll_enabled && !self.user_scrolled_since_play {
let playhead_x = self.time_to_x(*shared.playback_time, grid_rect);
let margin = grid_rect.width() * 0.2;
if playhead_x > grid_rect.max.x - margin || playhead_x < grid_rect.min.x + margin {
self.viewport_start_time = *shared.playback_time - (grid_rect.width() * 0.4 / self.pixels_per_second) as f64;
self.viewport_start_time = self.viewport_start_time.max(0.0);
}
self.viewport_start_time = *shared.playback_time - (grid_rect.width() * 0.5 / self.pixels_per_second) as f64;
self.viewport_start_time = self.viewport_start_time.max(0.0);
}
// Reset user_scrolled when playback stops
@ -635,29 +639,53 @@ impl PianoRollPane {
// Scroll/zoom handling
if let Some(hover_pos) = response.hover_pos() {
let scroll = ui.input(|i| i.smooth_scroll_delta);
let mut zoom_handled = false;
if ctrl_held {
// Zoom
if scroll.y != 0.0 {
let zoom_factor = if scroll.y > 0.0 { 1.1 } else { 1.0 / 1.1 };
let time_at_cursor = self.x_to_time(hover_pos.x, grid_rect);
self.pixels_per_second = (self.pixels_per_second * zoom_factor as f32).clamp(20.0, 2000.0);
// Keep cursor at same time position
self.viewport_start_time = time_at_cursor - ((hover_pos.x - grid_rect.min.x) / self.pixels_per_second) as f64;
// Check raw mouse wheel events to distinguish mouse wheel from trackpad
let raw_wheel = ui.input(|i| {
i.events.iter().find_map(|e| {
if let egui::Event::MouseWheel { unit, delta, modifiers } = e {
Some((*unit, *delta, *modifiers))
} else {
None
}
})
});
if let Some((unit, delta, modifiers)) = raw_wheel {
match unit {
egui::MouseWheelUnit::Line | egui::MouseWheelUnit::Page => {
// Mouse wheel: always zoom horizontally
let zoom_delta = delta.y * 0.005;
self.apply_zoom_at_point(zoom_delta, hover_pos.x, grid_rect);
self.user_scrolled_since_play = true;
zoom_handled = true;
}
egui::MouseWheelUnit::Point => {
if ctrl_held || modifiers.ctrl {
// Trackpad + Ctrl: zoom
let zoom_delta = delta.y * 0.005;
self.apply_zoom_at_point(zoom_delta, hover_pos.x, grid_rect);
self.user_scrolled_since_play = true;
zoom_handled = true;
}
}
}
}
// Trackpad panning (smooth scroll without Ctrl)
if !zoom_handled {
let scroll = ui.input(|i| i.smooth_scroll_delta);
if scroll.x.abs() > 0.0 {
self.viewport_start_time -= (scroll.x / self.pixels_per_second) as f64;
self.viewport_start_time = self.viewport_start_time.max(0.0);
self.user_scrolled_since_play = true;
}
} else if shift_held || scroll.x.abs() > 0.0 {
// Horizontal scroll
let dx = if scroll.x.abs() > 0.0 { scroll.x } else { scroll.y };
self.viewport_start_time -= (dx / self.pixels_per_second) as f64;
self.viewport_start_time = self.viewport_start_time.max(0.0);
self.user_scrolled_since_play = true;
} else {
// Vertical scroll
self.scroll_y -= scroll.y;
let max_scroll = (MAX_NOTE - MIN_NOTE + 1) as f32 * self.note_height - grid_rect.height();
self.scroll_y = self.scroll_y.clamp(0.0, max_scroll.max(0.0));
if scroll.y.abs() > 0.0 {
self.scroll_y -= scroll.y;
let max_scroll = (MAX_NOTE - MIN_NOTE + 1) as f32 * self.note_height - grid_rect.height();
self.scroll_y = self.scroll_y.clamp(0.0, max_scroll.max(0.0));
}
}
}
@ -1308,28 +1336,50 @@ impl PianoRollPane {
// Handle scroll/zoom
let response = ui.allocate_rect(rect, egui::Sense::click_and_drag());
if let Some(hover_pos) = response.hover_pos() {
let scroll = ui.input(|i| i.smooth_scroll_delta);
let ctrl_held = ui.input(|i| i.modifiers.ctrl);
let shift_held = ui.input(|i| i.modifiers.shift);
let mut zoom_handled = false;
if ctrl_held && scroll.y != 0.0 {
// Zoom
let zoom_factor = if scroll.y > 0.0 { 1.1 } else { 1.0 / 1.1 };
let time_at_cursor = self.x_to_time(hover_pos.x, view_rect);
self.pixels_per_second = (self.pixels_per_second * zoom_factor as f32).clamp(20.0, 2000.0);
self.viewport_start_time = time_at_cursor - ((hover_pos.x - view_rect.min.x) / self.pixels_per_second) as f64;
self.user_scrolled_since_play = true;
} else if shift_held || scroll.x.abs() > 0.0 {
// Horizontal scroll
let dx = if scroll.x.abs() > 0.0 { scroll.x } else { scroll.y };
self.viewport_start_time -= (dx / self.pixels_per_second) as f64;
self.viewport_start_time = self.viewport_start_time.max(0.0);
self.user_scrolled_since_play = true;
} else {
// Vertical scroll (same as MIDI mode)
self.scroll_y -= scroll.y;
let max_scroll = (MAX_NOTE - MIN_NOTE + 1) as f32 * self.note_height - view_rect.height();
self.scroll_y = self.scroll_y.clamp(0.0, max_scroll.max(0.0));
let raw_wheel = ui.input(|i| {
i.events.iter().find_map(|e| {
if let egui::Event::MouseWheel { unit, delta, modifiers } = e {
Some((*unit, *delta, *modifiers))
} else {
None
}
})
});
if let Some((unit, delta, modifiers)) = raw_wheel {
match unit {
egui::MouseWheelUnit::Line | egui::MouseWheelUnit::Page => {
let zoom_delta = delta.y * 0.005;
self.apply_zoom_at_point(zoom_delta, hover_pos.x, view_rect);
self.user_scrolled_since_play = true;
zoom_handled = true;
}
egui::MouseWheelUnit::Point => {
if ctrl_held || modifiers.ctrl {
let zoom_delta = delta.y * 0.005;
self.apply_zoom_at_point(zoom_delta, hover_pos.x, view_rect);
self.user_scrolled_since_play = true;
zoom_handled = true;
}
}
}
}
if !zoom_handled {
let scroll = ui.input(|i| i.smooth_scroll_delta);
if scroll.x.abs() > 0.0 {
self.viewport_start_time -= (scroll.x / self.pixels_per_second) as f64;
self.viewport_start_time = self.viewport_start_time.max(0.0);
self.user_scrolled_since_play = true;
}
if scroll.y.abs() > 0.0 {
self.scroll_y -= scroll.y;
let max_scroll = (MAX_NOTE - MIN_NOTE + 1) as f32 * self.note_height - view_rect.height();
self.scroll_y = self.scroll_y.clamp(0.0, max_scroll.max(0.0));
}
}
}
@ -1340,14 +1390,10 @@ impl PianoRollPane {
// Keyboard on top (same as MIDI mode)
self.render_keyboard(&painter, keyboard_rect);
// Auto-scroll during playback
// Auto-scroll during playback: pin playhead to center of viewport
if *shared.is_playing && self.auto_scroll_enabled && !self.user_scrolled_since_play {
let playhead_x = self.time_to_x(*shared.playback_time, view_rect);
let margin = view_rect.width() * 0.2;
if playhead_x > view_rect.max.x - margin || playhead_x < view_rect.min.x + margin {
self.viewport_start_time = *shared.playback_time - (view_rect.width() * 0.4 / self.pixels_per_second) as f64;
self.viewport_start_time = self.viewport_start_time.max(0.0);
}
self.viewport_start_time = *shared.playback_time - (view_rect.width() * 0.5 / self.pixels_per_second) as f64;
self.viewport_start_time = self.viewport_start_time.max(0.0);
}
if !*shared.is_playing {