implement nudge view while performing certain pen actions (#783)

* implement nudging camera in certain pen actions * split horizontal/vertical nudges needed * increase nudge amount * satisfy clippy * more nudge directions * nudge when moving content in vertical-space tool * update nudge needed function * explicit match for nudge not needed
flxzt · Aug 28, 2023 · dff923a · dff923a
1 parent 7ea4541
commit dff923a
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Showing 5 changed files with 105 additions and 17 deletions.
diff --git a/crates/rnote-engine/src/camera.rs b/crates/rnote-engine/src/camera.rs
@@ -8,6 +8,18 @@ use rnote_compose::ext::AabbExt;
 use serde::{Deserialize, Serialize};
 use std::time::Duration;
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+pub enum NudgeDirection {
+    North,
+    NorthEast,
+    East,
+    SouthEast,
+    South,
+    SouthWest,
+    West,
+    NorthWest,
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize)]
 #[serde(default, rename = "camera")]
 pub struct Camera {
@@ -282,6 +294,60 @@ impl Camera {
             ))
             .scale(total_zoom as f32, total_zoom as f32)
     }
+
+    /// Detects if a nudge is needed, meaning: the position is close to an edge of the current viewport.
+    pub fn detect_nudge_needed(&self, pos: na::Vector2<f64>) -> Option<NudgeDirection> {
+        const NUDGE_VIEWPORT_DIST: f64 = 10.0;
+        let viewport = self.viewport();
+        let nudge_north = pos[1] <= viewport.mins[1] + NUDGE_VIEWPORT_DIST;
+        let nudge_east = pos[0] >= viewport.maxs[0] - NUDGE_VIEWPORT_DIST;
+        let nudge_south = pos[1] >= viewport.maxs[1] - NUDGE_VIEWPORT_DIST;
+        let nudge_west = pos[0] <= viewport.mins[0] + NUDGE_VIEWPORT_DIST;
+
+        match (nudge_north, nudge_east, nudge_south, nudge_west) {
+            (true, false, _, false) => Some(NudgeDirection::North),
+            (true, true, _, _) => Some(NudgeDirection::NorthEast),
+            (false, true, false, _) => Some(NudgeDirection::East),
+            (_, true, true, _) => Some(NudgeDirection::SouthEast),
+            (_, false, true, false) => Some(NudgeDirection::South),
+            (_, _, true, true) => Some(NudgeDirection::SouthWest),
+            (false, _, false, true) => Some(NudgeDirection::West),
+            (true, _, _, true) => Some(NudgeDirection::NorthWest),
+            (false, false, false, false) => None,
+        }
+    }
+
+    pub fn nudge_by(
+        &mut self,
+        amount: f64,
+        direction: NudgeDirection,
+        doc: &Document,
+    ) -> WidgetFlags {
+        let nudge_offset = match direction {
+            NudgeDirection::North => na::vector![0., -amount],
+            NudgeDirection::NorthEast => na::vector![amount, -amount],
+            NudgeDirection::East => na::vector![amount, 0.],
+            NudgeDirection::SouthEast => na::vector![amount, amount],
+            NudgeDirection::South => na::vector![0., amount],
+            NudgeDirection::SouthWest => na::vector![-amount, amount],
+            NudgeDirection::West => na::vector![-amount, 0.],
+            NudgeDirection::NorthWest => na::vector![-amount, -amount],
+        };
+        self.set_offset(self.offset() + nudge_offset, doc)
+    }
+
+    pub fn nudge(&mut self, direction: NudgeDirection, doc: &Document) -> WidgetFlags {
+        const NUDGE_AMOUNT: f64 = 20.0;
+        self.nudge_by(NUDGE_AMOUNT, direction, doc)
+    }
+
+    pub fn nudge_w_pos(&mut self, pos: na::Vector2<f64>, doc: &Document) -> WidgetFlags {
+        let mut widget_flags = WidgetFlags::default();
+        if let Some(nudge_direction) = self.detect_nudge_needed(pos) {
+            widget_flags |= self.nudge(nudge_direction, doc);
+        }
+        widget_flags
+    }
 }
 
 #[cfg(test)]

diff --git a/crates/rnote-engine/src/pens/penholder.rs b/crates/rnote-engine/src/pens/penholder.rs
@@ -5,6 +5,7 @@ use super::{
     Brush, Eraser, Pen, PenBehaviour, PenMode, PenStyle, Selector, Shaper, Shortcuts, Tools,
     Typewriter,
 };
+use crate::camera::NudgeDirection;
 use crate::engine::{EngineView, EngineViewMut};
 use crate::pens::shortcuts::ShortcutAction;
 use crate::widgetflags::WidgetFlags;
@@ -297,52 +298,56 @@ impl PenHolder {
                 modifier_keys,
             } => match keyboard_key {
                 KeyboardKey::NavUp => {
-                    let y_offset = if modifier_keys.contains(&ModifierKey::KeyboardCtrl) {
-                        -engine_view.camera.size()[1]
+                    let nudge_amount = if modifier_keys.contains(&ModifierKey::KeyboardCtrl) {
+                        engine_view.camera.size()[1]
                     } else {
-                        -engine_view.camera.size()[1] * MOVE_VIEW_FACTOR
+                        engine_view.camera.size()[1] * MOVE_VIEW_FACTOR
                     };
-                    widget_flags |= engine_view.camera.set_offset(
-                        engine_view.camera.offset() + na::vector![0.0, y_offset],
+                    widget_flags |= engine_view.camera.nudge_by(
+                        nudge_amount,
+                        NudgeDirection::North,
                         engine_view.doc,
                     );
 
                     EventPropagation::Stop
                 }
                 KeyboardKey::NavDown => {
-                    let y_offset = if modifier_keys.contains(&ModifierKey::KeyboardCtrl) {
+                    let nudge_amount = if modifier_keys.contains(&ModifierKey::KeyboardCtrl) {
                         engine_view.camera.size()[1]
                     } else {
                         engine_view.camera.size()[1] * MOVE_VIEW_FACTOR
                     };
-                    widget_flags |= engine_view.camera.set_offset(
-                        engine_view.camera.offset() + na::vector![0.0, y_offset],
+                    widget_flags |= engine_view.camera.nudge_by(
+                        nudge_amount,
+                        NudgeDirection::East,
                         engine_view.doc,
                     );
 
                     EventPropagation::Stop
                 }
                 KeyboardKey::NavLeft => {
-                    let x_offset = if modifier_keys.contains(&ModifierKey::KeyboardCtrl) {
-                        -engine_view.camera.size()[0]
+                    let nudge_amount = if modifier_keys.contains(&ModifierKey::KeyboardCtrl) {
+                        engine_view.camera.size()[0]
                     } else {
-                        -engine_view.camera.size()[0] * MOVE_VIEW_FACTOR
+                        engine_view.camera.size()[0] * MOVE_VIEW_FACTOR
                     };
-                    widget_flags |= engine_view.camera.set_offset(
-                        engine_view.camera.offset() + na::vector![x_offset, 0.0],
+                    widget_flags |= engine_view.camera.nudge_by(
+                        nudge_amount,
+                        NudgeDirection::West,
                         engine_view.doc,
                     );
 
                     EventPropagation::Stop
                 }
                 KeyboardKey::NavRight => {
-                    let x_offset = if modifier_keys.contains(&ModifierKey::KeyboardCtrl) {
+                    let nudge_amount = if modifier_keys.contains(&ModifierKey::KeyboardCtrl) {
                         engine_view.camera.size()[0]
                     } else {
                         engine_view.camera.size()[0] * MOVE_VIEW_FACTOR
                     };
-                    widget_flags |= engine_view.camera.set_offset(
-                        engine_view.camera.offset() + na::vector![x_offset, 0.0],
+                    widget_flags |= engine_view.camera.nudge_by(
+                        nudge_amount,
+                        NudgeDirection::South,
                         engine_view.doc,
                     );
 

diff --git a/crates/rnote-engine/src/pens/selector/penevents.rs b/crates/rnote-engine/src/pens/selector/penevents.rs
@@ -46,6 +46,8 @@ impl Selector {
                     path,
                     element,
                 );
+                // possibly nudge camera
+                widget_flags |= engine_view.camera.nudge_w_pos(element.pos, engine_view.doc);
 
                 EventResult {
                     handled: true,
@@ -172,11 +174,15 @@ impl Selector {
                         if offset.magnitude()
                             > Self::TRANSLATE_MAGNITUDE_THRESHOLD / engine_view.camera.total_zoom()
                         {
+                            // move selection
                             engine_view.store.translate_strokes(selection, offset);
                             engine_view
                                 .store
                                 .translate_strokes_images(selection, offset);
                             *selection_bounds = selection_bounds.translate(offset);
+                            // possibly nudge camera
+                            widget_flags |=
+                                engine_view.camera.nudge_w_pos(element.pos, engine_view.doc);
 
                             // strokes that were not visible previously might come into view
                             engine_view.store.regenerate_rendering_in_viewport_threaded(
@@ -269,17 +275,20 @@ impl Selector {
                         );
                         let scale = new_extents.component_div(&selection_bounds.extents());
 
+                        // resize strokes
                         engine_view
                             .store
                             .scale_strokes_with_pivot(selection, scale, pivot);
                         engine_view
                             .store
                             .scale_strokes_images_with_pivot(selection, scale, pivot);
-
                         *selection_bounds = selection_bounds
                             .translate(-pivot)
                             .scale_non_uniform(scale)
                             .translate(pivot);
+                        // possibly nudge camera
+                        widget_flags |=
+                            engine_view.camera.nudge_w_pos(element.pos, engine_view.doc);
                     }
                 }
 

diff --git a/crates/rnote-engine/src/pens/tools.rs b/crates/rnote-engine/src/pens/tools.rs
@@ -350,6 +350,10 @@ impl PenBehaviour for Tools {
                                 &self.verticalspace_tool.strokes_below,
                                 na::vector![0.0, y_offset],
                             );
+                            // possibly nudge camera
+                            widget_flags |=
+                                engine_view.camera.nudge_w_pos(element.pos, engine_view.doc);
+                            // new strokes might come into view
                             engine_view.store.regenerate_rendering_in_viewport_threaded(
                                 engine_view.tasks_tx.clone(),
                                 false,

diff --git a/crates/rnote-engine/src/pens/typewriter/penevents.rs b/crates/rnote-engine/src/pens/typewriter/penevents.rs
@@ -220,10 +220,14 @@ impl Typewriter {
                         if offset.magnitude()
                             > Self::TRANSLATE_MAGNITUDE_THRESHOLD / engine_view.camera.total_zoom()
                         {
+                            // move text
                             engine_view.store.translate_strokes(&[*stroke_key], offset);
                             engine_view
                                 .store
                                 .translate_strokes_images(&[*stroke_key], offset);
+                            // possibly nudge camera
+                            widget_flags |=
+                                engine_view.camera.nudge_w_pos(element.pos, engine_view.doc);
 
                             *current_pos = element.pos;