1 files changed, 167 insertions, 0 deletions
diff --git a/packages/excalidraw/scene/Renderer.ts b/packages/excalidraw/scene/Renderer.ts
new file mode 100644
index 0000000..8048d20
--- /dev/null
+++ b/packages/excalidraw/scene/Renderer.ts
@@ -0,0 +1,167 @@
+import { isElementInViewport } from "../element/sizeHelpers";
+import { isImageElement } from "../element/typeChecks";
+import type {
+  ExcalidrawElement,
+  NonDeletedElementsMap,
+  NonDeletedExcalidrawElement,
+} from "../element/types";
+import { renderInteractiveSceneThrottled } from "../renderer/interactiveScene";
+import { renderStaticSceneThrottled } from "../renderer/staticScene";
+
+import type { AppState } from "../types";
+import { memoize, toBrandedType } from "../utils";
+import type Scene from "./Scene";
+import type { RenderableElementsMap } from "./types";
+
+export class Renderer {
+  private scene: Scene;
+
+  constructor(scene: Scene) {
+    this.scene = scene;
+  }
+
+  public getRenderableElements = (() => {
+    const getVisibleCanvasElements = ({
+      elementsMap,
+      zoom,
+      offsetLeft,
+      offsetTop,
+      scrollX,
+      scrollY,
+      height,
+      width,
+    }: {
+      elementsMap: NonDeletedElementsMap;
+      zoom: AppState["zoom"];
+      offsetLeft: AppState["offsetLeft"];
+      offsetTop: AppState["offsetTop"];
+      scrollX: AppState["scrollX"];
+      scrollY: AppState["scrollY"];
+      height: AppState["height"];
+      width: AppState["width"];
+    }): readonly NonDeletedExcalidrawElement[] => {
+      const visibleElements: NonDeletedExcalidrawElement[] = [];
+      for (const element of elementsMap.values()) {
+        if (
+          isElementInViewport(
+            element,
+            width,
+            height,
+            {
+              zoom,
+              offsetLeft,
+              offsetTop,
+              scrollX,
+              scrollY,
+            },
+            elementsMap,
+          )
+        ) {
+          visibleElements.push(element);
+        }
+      }
+      return visibleElements;
+    };
+
+    const getRenderableElements = ({
+      elements,
+      editingTextElement,
+      newElementId,
+      pendingImageElementId,
+    }: {
+      elements: readonly NonDeletedExcalidrawElement[];
+      editingTextElement: AppState["editingTextElement"];
+      newElementId: ExcalidrawElement["id"] | undefined;
+      pendingImageElementId: AppState["pendingImageElementId"];
+    }) => {
+      const elementsMap = toBrandedType<RenderableElementsMap>(new Map());
+
+      for (const element of elements) {
+        if (isImageElement(element)) {
+          if (
+            // => not placed on canvas yet (but in elements array)
+            pendingImageElementId === element.id
+          ) {
+            continue;
+          }
+        }
+
+        if (newElementId === element.id) {
+          continue;
+        }
+
+        // we don't want to render text element that's being currently edited
+        // (it's rendered on remote only)
+        if (
+          !editingTextElement ||
+          editingTextElement.type !== "text" ||
+          element.id !== editingTextElement.id
+        ) {
+          elementsMap.set(element.id, element);
+        }
+      }
+      return elementsMap;
+    };
+
+    return memoize(
+      ({
+        zoom,
+        offsetLeft,
+        offsetTop,
+        scrollX,
+        scrollY,
+        height,
+        width,
+        editingTextElement,
+        newElementId,
+        pendingImageElementId,
+        // cache-invalidation nonce
+        sceneNonce: _sceneNonce,
+      }: {
+        zoom: AppState["zoom"];
+        offsetLeft: AppState["offsetLeft"];
+        offsetTop: AppState["offsetTop"];
+        scrollX: AppState["scrollX"];
+        scrollY: AppState["scrollY"];
+        height: AppState["height"];
+        width: AppState["width"];
+        editingTextElement: AppState["editingTextElement"];
+        /** note: first render of newElement will always bust the cache
+         * (we'd have to prefilter elements outside of this function) */
+        newElementId: ExcalidrawElement["id"] | undefined;
+        pendingImageElementId: AppState["pendingImageElementId"];
+        sceneNonce: ReturnType<InstanceType<typeof Scene>["getSceneNonce"]>;
+      }) => {
+        const elements = this.scene.getNonDeletedElements();
+
+        const elementsMap = getRenderableElements({
+          elements,
+          editingTextElement,
+          newElementId,
+          pendingImageElementId,
+        });
+
+        const visibleElements = getVisibleCanvasElements({
+          elementsMap,
+          zoom,
+          offsetLeft,
+          offsetTop,
+          scrollX,
+          scrollY,
+          height,
+          width,
+        });
+
+        return { elementsMap, visibleElements };
+      },
+    );
+  })();
+
+  // NOTE Doesn't destroy everything (scene, rc, etc.) because it may not be
+  // safe to break TS contract here (for upstream cases)
+  public destroy() {
+    renderInteractiveSceneThrottled.cancel();
+    renderStaticSceneThrottled.cancel();
+    this.getRenderableElements.clear();
+  }
+}