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feat!: touchpad scroll for zoom (with Ctrl) and pan #535

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Merged
RobertMueller2 merged 1 commit into from
Jun 14, 2026
Merged

feat!: touchpad scroll for zoom (with Ctrl) and pan #535

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9 changes: 9 additions & 0 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -54,6 +54,15 @@ All configuration is done either at the config file in `XDG_CONFIG_DIR/.config/s
- <kbd>Ctrl+Z</kbd>: Undo
- <kbd>Alt</kbd>+(<kbd>Left</kbd>/<kbd>Right</kbd>/<kbd>Up</kbd>/<kbd>Down</kbd>): Pan, also available with middle mouse button drag <sup>0.20.1</sup>

Mouse:
- <kbd>Ctrl+Wheel</kbd>: Zoom in/out <sup>NEXTRELEASE</sup>
- <kbd>Middle</kbd>: Pan

Touchpad: <sup>NEXTRELEASE</sup>
- <kbd>Pinch</kbd>: Zoom (two finger)
- <kbd>Ctrl+Scroll</kbd>: Zoom in/out (two finger scroll)
- <kbd>Scroll</kbd>: Pan (two finger scroll)

#### Color Selection Shortcuts <sup>0.20.1</sup>

<kbd>1</kbd>, <kbd>2</kbd>, <kbd>3</kbd>, …, <kbd>9</kbd>, <kbd>0</kbd> — select nth color from the color palette
Expand Down
4 changes: 2 additions & 2 deletions src/femtovg_area/imp.rs
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Expand Up @@ -690,11 +690,11 @@ impl FemtoVgAreaMut {
}

if self.is_reset {
//centered
// centered
self.is_reset = false;
self.offset = center_offset;
} else {
//dragged
// dragged
self.offset = center_offset + self.drag_offset;
}
}
Expand Down
8 changes: 8 additions & 0 deletions src/femtovg_area/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -125,6 +125,14 @@ impl FemtoVGArea {
.set_pointer_offset(offset * self.scale_factor() as f32);
}

pub fn set_pointer_offset_center(&self) {
let center = Vec2D::new(
self.allocated_width() as f32 / 2.0,
self.allocated_height() as f32 / 2.0,
);
self.set_pointer_offset(center);
}

pub fn set_drag_offset(&self, offset: Vec2D) {
self.imp()
.inner()
Expand Down
95 changes: 83 additions & 12 deletions src/sketch_board.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,9 @@ const SAVE_AS_LAST_DIR_MAX_BYTES: u64 = 10_000;
#[derive(Debug, Clone)]
pub enum SketchBoardInput {
InputEvent(InputEvent),
PinchStart,
PinchScale(f32),
PinchEnd,
ToolbarEvent(ToolbarEvent),
RenderResult(RenderedImage, Vec<Action>),
RenderResultFollowup(Option<Pixbuf>, Vec<Action>, Option<String>),
Expand Down Expand Up @@ -106,6 +109,7 @@ pub struct MouseEventMsg {
pub button: MouseButton,
pub modifier: ModifierType,
pub screen_pos: Vec2D,
pub is_touchpad: bool,
pub pos: Vec2D,
pub n_pressed: i32,
pub release: bool,
Expand All @@ -127,6 +131,7 @@ impl SketchBoardInput {
modifier,
screen_pos: pos,
pos,
is_touchpad: false,
release,
}))
}
Expand All @@ -146,14 +151,20 @@ impl SketchBoardInput {
SketchBoardInput::CommitEvent(event)
}

pub fn new_scroll_event(delta_y: f64) -> SketchBoardInput {
pub fn new_scroll_event(
delta_x: f64,
delta_y: f64,
modifier: ModifierType,
is_touchpad: bool,
) -> SketchBoardInput {
SketchBoardInput::InputEvent(InputEvent::Mouse(MouseEventMsg {
type_: MouseEventType::Scroll,
button: MouseButton::Middle,
n_pressed: 0,
modifier: ModifierType::empty(),
screen_pos: Vec2D::new(0.0, delta_y as f32),
pos: Vec2D::new(0.0, delta_y as f32),
modifier,
screen_pos: Vec2D::new(delta_x as f32, delta_y as f32),
pos: Vec2D::new(delta_x as f32, delta_y as f32),
is_touchpad,
release: false,
}))
}
Expand Down Expand Up @@ -223,11 +234,24 @@ impl InputEvent {
}

MouseEventType::Scroll => {
let factor = APP_CONFIG.read().zoom_factor();
match me.pos.y {
v if v < 0.0 => renderer.set_zoom_scale(factor),
v if v > 0.0 => renderer.set_zoom_scale(1f32 / factor),
_ => {}
if me.modifier.contains(ModifierType::CONTROL_MASK) {
let mut factor = APP_CONFIG.read().zoom_factor();
if me.is_touchpad {
factor = 1.0 + (factor - 1.0) / 2.0; // decrease a bit

@robertwidfen robertwidfen Jun 11, 2026

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See below

};
match me.pos.y {
v if v < 0.0 => renderer.set_zoom_scale(factor),
v if v > 0.0 => renderer.set_zoom_scale(1f32 / factor),
_ => {}
}
} else {
let pan_step_size = if me.is_touchpad {
-2.0 // invert for natural scrolling and decrease a bit
Comment thread
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} else {
APP_CONFIG.read().pan_step_size()
};
renderer.set_drag_offset(me.screen_pos * pan_step_size);
renderer.store_last_offset();
}
renderer.request_render(&[]);
None
Expand All @@ -249,6 +273,7 @@ pub struct SketchBoard {
active_tool: Rc<RefCell<dyn Tool>>,
tool_edit_mode: bool,
tools: ToolsManager,
pinch_last_scale: f32,
style: Style,
im_context: gtk::IMMulticontext,
last_saved_filepath: RefCell<Option<String>>,
Expand Down Expand Up @@ -1014,13 +1039,38 @@ impl Component for SketchBoard {
},

add_controller = gtk::EventControllerScroll{
set_flags: gtk::EventControllerScrollFlags::VERTICAL,
connect_scroll[sender] => move |_, _, dy| {
sender.input(SketchBoardInput::new_scroll_event(dy));
set_flags: gtk::EventControllerScrollFlags::VERTICAL
| gtk::EventControllerScrollFlags::HORIZONTAL,
connect_scroll[sender] => move |controller, dx, dy| {
let is_touchpad = controller
.current_event()
.and_then(|event| event.device())
.is_some_and(|device| {
matches!(device.source(), gtk::gdk::InputSource::Touchpad)
});

sender.input(SketchBoardInput::new_scroll_event(
dx,
dy,
controller.current_event_state(),
is_touchpad,
));
relm4::gtk::glib::Propagation::Stop
},
},

add_controller = gtk::GestureZoom {
connect_begin[sender] => move |_, _| {
sender.input(SketchBoardInput::PinchStart);
},
connect_scale_changed[sender] => move |_, scale| {
sender.input(SketchBoardInput::PinchScale(scale as f32));
},
connect_end[sender] => move |_, _| {
sender.input(SketchBoardInput::PinchEnd);
},
},

add_controller = gtk::EventControllerKey {
connect_key_pressed[sender] => move |controller, key, code, modifier | {
if let Some(im_context) = controller.im_context() {
Expand Down Expand Up @@ -1203,6 +1253,26 @@ impl Component for SketchBoard {
}
}
}
SketchBoardInput::PinchStart => {
self.pinch_last_scale = 1.0;
ToolUpdateResult::Unmodified
}
SketchBoardInput::PinchScale(scale) => {
if scale.is_finite() && scale > 0.0 && self.pinch_last_scale > 0.0 {
let factor = scale / self.pinch_last_scale;
if factor.is_finite() && factor > 0.0 {
self.renderer.set_pointer_offset_center();
self.renderer.set_zoom_scale(factor);
self.renderer.request_render(&[]);
}
self.pinch_last_scale = scale;
}
ToolUpdateResult::Unmodified
}
SketchBoardInput::PinchEnd => {
self.pinch_last_scale = 1.0;
ToolUpdateResult::Unmodified
}
SketchBoardInput::ToolbarEvent(toolbar_event) => {
self.handle_toolbar_event(toolbar_event, sender)
}
Expand Down Expand Up @@ -1274,6 +1344,7 @@ impl Component for SketchBoard {
active_tool: tools.get(&config.initial_tool()),
tool_edit_mode: false,
style: Style::default(),
pinch_last_scale: 1.0,
tools,
im_context,
last_saved_filepath: RefCell::new(None),
Expand Down
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