feat: partition main canvas vertically (#6759)

Co-authored-by: Marcel Mraz <marcel.mraz@adacta-fintech.com>
Co-authored-by: dwelle <luzar.david@gmail.com>

src/components/canvases/StaticCanvas.tsx

@@ -0,0 +1,113 @@
+import React, { useEffect, useRef } from "react";
+import { RoughCanvas } from "roughjs/bin/canvas";
+import { renderStaticScene } from "../../renderer/renderScene";
+import { isRenderThrottlingEnabled, isShallowEqual } from "../../utils";
+import type { AppState, StaticCanvasAppState } from "../../types";
+import type { StaticCanvasRenderConfig } from "../../scene/types";
+import type { NonDeletedExcalidrawElement } from "../../element/types";
+
+type StaticCanvasProps = {
+  canvas: HTMLCanvasElement;
+  rc: RoughCanvas;
+  elements: readonly NonDeletedExcalidrawElement[];
+  visibleElements: readonly NonDeletedExcalidrawElement[];
+  versionNonce: number | undefined;
+  selectionNonce: number | undefined;
+  scale: number;
+  appState: StaticCanvasAppState;
+  renderConfig: StaticCanvasRenderConfig;
+};
+
+const StaticCanvas = (props: StaticCanvasProps) => {
+  const wrapperRef = useRef<HTMLDivElement>(null);
+  const isComponentMounted = useRef(false);
+
+  useEffect(() => {
+    const wrapper = wrapperRef.current;
+    if (!wrapper) {
+      return;
+    }
+
+    const canvas = props.canvas;
+
+    if (!isComponentMounted.current) {
+      isComponentMounted.current = true;
+
+      wrapper.replaceChildren(canvas);
+      canvas.classList.add("excalidraw__canvas", "static");
+    }
+
+    canvas.style.width = `${props.appState.width}px`;
+    canvas.style.height = `${props.appState.height}px`;
+    canvas.width = props.appState.width * props.scale;
+    canvas.height = props.appState.height * props.scale;
+
+    renderStaticScene(
+      {
+        canvas,
+        rc: props.rc,
+        scale: props.scale,
+        elements: props.elements,
+        visibleElements: props.visibleElements,
+        appState: props.appState,
+        renderConfig: props.renderConfig,
+      },
+      isRenderThrottlingEnabled(),
+    );
+  });
+
+  return <div className="excalidraw__canvas-wrapper" ref={wrapperRef} />;
+};
+
+const getRelevantAppStateProps = (
+  appState: AppState,
+): Omit<
+  StaticCanvasAppState,
+  | "editingElement"
+  | "selectedElementIds"
+  | "editingGroupId"
+  | "frameToHighlight"
+> => ({
+  zoom: appState.zoom,
+  scrollX: appState.scrollX,
+  scrollY: appState.scrollY,
+  width: appState.width,
+  height: appState.height,
+  viewModeEnabled: appState.viewModeEnabled,
+  offsetLeft: appState.offsetLeft,
+  offsetTop: appState.offsetTop,
+  theme: appState.theme,
+  pendingImageElementId: appState.pendingImageElementId,
+  shouldCacheIgnoreZoom: appState.shouldCacheIgnoreZoom,
+  viewBackgroundColor: appState.viewBackgroundColor,
+  exportScale: appState.exportScale,
+  selectedElementsAreBeingDragged: appState.selectedElementsAreBeingDragged,
+  gridSize: appState.gridSize,
+  frameRendering: appState.frameRendering,
+});
+
+const areEqual = (
+  prevProps: StaticCanvasProps,
+  nextProps: StaticCanvasProps,
+) => {
+  if (
+    prevProps.versionNonce !== nextProps.versionNonce ||
+    prevProps.scale !== nextProps.scale ||
+    // we need to memoize on element arrays because they may have renewed
+    // even if versionNonce didn't change (e.g. we filter elements out based
+    // on appState)
+    prevProps.elements !== nextProps.elements ||
+    prevProps.visibleElements !== nextProps.visibleElements
+  ) {
+    return false;
+  }
+
+  return isShallowEqual(
+    // asserting AppState because we're being passed the whole AppState
+    // but resolve to only the StaticCanvas-relevant props
+    getRelevantAppStateProps(prevProps.appState as AppState),
+    getRelevantAppStateProps(nextProps.appState as AppState),
+  );
+};
+
+export default React.memo(StaticCanvas, areEqual);