Improve scrollbar behavior (#351)

* Change scrollbar behavior

* Leave space at the end of the scrollbar

* Change mid to center

* Use shorter array initialization

* Add space around scrollbar

* Fix scrollbar spacing

* Smooth end of scrollbars

* Add page up and down

* Page up and down on click in scrollbar track

* Add shift pageup to translate horizontally

frontend/wasm/src/document.rs

@@ -312,6 +312,13 @@ pub fn translate_canvas(delta_x: f64, delta_y: f64) -> Result<(), JsValue> {
 	EDITOR_STATE.with(|editor| editor.borrow_mut().handle_message(ev)).map_err(convert_error)
 }
 
+/// Translates document (in viewport coords)
+#[wasm_bindgen]
+pub fn translate_canvas_by_fraction(delta_x: f64, delta_y: f64) -> Result<(), JsValue> {
+	let ev = MovementMessage::TranslateCanvasByViewportFraction((delta_x, delta_y).into());
+	EDITOR_STATE.with(|editor| editor.borrow_mut().handle_message(ev)).map_err(convert_error)
+}
+
 /// Update the list of selected layers. The layer paths have to be stored in one array and are separated by LayerId::MAX
 #[wasm_bindgen]
 pub fn select_layers(paths: Vec<LayerId>) -> Result<(), JsValue> {

frontend/wasm/src/wrappers.rs

@@ -151,6 +151,8 @@ pub fn translate_key(name: &str) -> Key {
 		"]" => KeyRightBracket,
 		"{" => KeyLeftCurlyBracket,
 		"}" => KeyRightCurlyBracket,
+		"pageup" => KeyPageUp,
+		"pagedown" => KeyPageDown,
 		_ => UnknownKey,
 	}
 }