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import { type PluginValue, ViewPlugin } from '@codemirror/view';
import { reaction } from 'mobx';
import type EditorStore from './EditorStore';
export const HOLDER_CLASS = 'cm-scroller-holder';
export const THUMB_CLASS = 'cm-scroller-thumb';
export const THUMB_Y_CLASS = 'cm-scroller-thumb-y';
export const THUMB_X_CLASS = 'cm-scroller-thumb-x';
export const THUMB_ACTIVE_CLASS = 'active';
export const GUTTER_DECORATION_CLASS = 'cm-scroller-gutter-decoration';
export const TOP_DECORATION_CLASS = 'cm-scroller-top-decoration';
export const SHADOW_WIDTH = 10;
export const SCROLLBAR_WIDTH = 12;
export default function scrollbarViewPlugin(
editorStore: EditorStore,
): ViewPlugin<PluginValue> {
return ViewPlugin.define((view) => {
const { scrollDOM } = view;
const { ownerDocument, parentElement: parentDOM } = scrollDOM;
if (parentDOM === null) {
return {};
}
const holder = ownerDocument.createElement('div');
holder.className = HOLDER_CLASS;
parentDOM.replaceChild(holder, scrollDOM);
holder.appendChild(scrollDOM);
let factorY = 1;
let factorX = 1;
const thumbY = ownerDocument.createElement('div');
thumbY.className = `${THUMB_CLASS} ${THUMB_Y_CLASS}`;
const scrollY = (event: MouseEvent) => {
scrollDOM.scrollBy({ top: event.movementY / factorY });
event.preventDefault();
};
const stopScrollY = () => {
thumbY.classList.remove(THUMB_ACTIVE_CLASS);
window.removeEventListener('mousemove', scrollY);
window.removeEventListener('mouseup', stopScrollY);
};
thumbY.addEventListener(
'mousedown',
() => {
thumbY.classList.add(THUMB_ACTIVE_CLASS);
window.addEventListener('mousemove', scrollY);
window.addEventListener('mouseup', stopScrollY, { passive: true });
},
{ passive: true },
);
holder.appendChild(thumbY);
const thumbX = ownerDocument.createElement('div');
thumbX.className = `${THUMB_CLASS} ${THUMB_X_CLASS}`;
const scrollX = (event: MouseEvent) => {
scrollDOM.scrollBy({ left: event.movementX / factorX });
};
const stopScrollX = () => {
thumbX.classList.remove(THUMB_ACTIVE_CLASS);
window.removeEventListener('mousemove', scrollX);
window.removeEventListener('mouseup', stopScrollX);
};
thumbX.addEventListener(
'mousedown',
() => {
thumbX.classList.add(THUMB_ACTIVE_CLASS);
window.addEventListener('mousemove', scrollX);
window.addEventListener('mouseup', stopScrollX, { passive: true });
},
{ passive: true },
);
holder.appendChild(thumbX);
const gutterDecoration = ownerDocument.createElement('div');
gutterDecoration.className = GUTTER_DECORATION_CLASS;
holder.appendChild(gutterDecoration);
const topDecoration = ownerDocument.createElement('div');
topDecoration.className = TOP_DECORATION_CLASS;
holder.appendChild(topDecoration);
const disposePanelReaction = reaction(
() => editorStore.searchPanel.state,
(panelOpen) => {
topDecoration.style.display = panelOpen ? 'none' : 'block';
},
{ fireImmediately: true },
);
let observer: ResizeObserver | undefined;
let gutters: Element | undefined;
let requested = false;
function update() {
requested = false;
if (gutters === undefined) {
gutters = scrollDOM.querySelector('.cm-gutters') ?? undefined;
if (gutters !== undefined && observer !== undefined) {
observer.observe(gutters);
}
}
const { height: scrollerHeight, width: scrollerWidth } =
scrollDOM.getBoundingClientRect();
const { scrollTop, scrollHeight, scrollLeft, scrollWidth } = scrollDOM;
const gutterWidth = gutters?.clientWidth ?? 0;
let trackYHeight = scrollerHeight;
if (scrollWidth > scrollerWidth) {
// Leave space for horizontal scrollbar.
trackYHeight -= SCROLLBAR_WIDTH;
// Alwalys leave space for annotation in the vertical scrollbar.
const trackXWidth = scrollerWidth - gutterWidth - SCROLLBAR_WIDTH;
const thumbWidth = trackXWidth * (scrollerWidth / scrollWidth);
factorX = (trackXWidth - thumbWidth) / (scrollWidth - scrollerWidth);
thumbX.style.display = 'block';
thumbX.style.height = `${SCROLLBAR_WIDTH}px`;
thumbX.style.width = `${thumbWidth}px`;
thumbX.style.left = `${gutterWidth + scrollLeft * factorX}px`;
} else {
thumbX.style.display = 'none';
}
if (scrollHeight > scrollerHeight) {
const thumbHeight = trackYHeight * (scrollerHeight / scrollHeight);
factorY =
(trackYHeight - thumbHeight) / (scrollHeight - scrollerHeight);
thumbY.style.display = 'block';
thumbY.style.height = `${thumbHeight}px`;
thumbY.style.width = `${SCROLLBAR_WIDTH}px`;
thumbY.style.top = `${scrollTop * factorY}px`;
} else {
thumbY.style.display = 'none';
}
gutterDecoration.style.left = `${gutterWidth}px`;
gutterDecoration.style.width = `${Math.max(
0,
Math.min(scrollLeft, SHADOW_WIDTH),
)}px`;
topDecoration.style.height = `${Math.max(
0,
Math.min(scrollTop, SHADOW_WIDTH),
)}px`;
}
function requestUpdate() {
if (!requested) {
requested = true;
view.requestMeasure({ read: update });
}
}
observer = new ResizeObserver(requestUpdate);
observer.observe(scrollDOM);
scrollDOM.addEventListener('scroll', requestUpdate);
requestUpdate();
return {
update: requestUpdate,
destroy() {
disposePanelReaction();
observer?.disconnect();
scrollDOM.removeEventListener('scroll', requestUpdate);
parentDOM.replaceChild(scrollDOM, holder);
},
};
});
}
|
