Don't use OffscreenCanvas on Safari

PiperOrigin-RevId: 522689566

mediapipe/tasks/web/vision/core/BUILD

@@ -40,6 +40,7 @@ mediapipe_ts_library(
         "//mediapipe/tasks/web/core:task_runner",
         "//mediapipe/web/graph_runner:graph_runner_image_lib_ts",
         "//mediapipe/web/graph_runner:graph_runner_ts",
+        "//mediapipe/web/graph_runner:platform_utils",
         "//mediapipe/web/graph_runner:register_model_resources_graph_service_ts",
     ],
 )

mediapipe/tasks/web/vision/core/vision_task_runner.ts

@@ -20,6 +20,7 @@ import {WasmFileset} from '../../../../tasks/web/core/wasm_fileset';
 import {ImageProcessingOptions} from '../../../../tasks/web/vision/core/image_processing_options';
 import {GraphRunner, ImageSource, WasmMediaPipeConstructor} from '../../../../web/graph_runner/graph_runner';
 import {SupportImage, WasmImage} from '../../../../web/graph_runner/graph_runner_image_lib';
+import {isWebKit} from '../../../../web/graph_runner/platform_utils';
 import {SupportModelResourcesGraphService} from '../../../../web/graph_runner/register_model_resources_graph_service';
 
 import {VisionTaskOptions} from './vision_task_options';
@@ -39,11 +40,13 @@ export class VisionGraphRunner extends GraphRunnerVisionType {}
  * GraphRunner should create its own canvas.
  */
 function createCanvas(): HTMLCanvasElement|OffscreenCanvas|undefined {
-  // Returns an HTML canvas or `undefined` if OffscreenCanvas is available
+  const supportsWebGL2ForOffscreenCanvas =
+      typeof OffscreenCanvas !== 'undefined' && !isWebKit();
+
+  // Returns an HTML canvas or `undefined` if OffscreenCanvas is fully supported
   // (since the graph runner can initialize its own OffscreenCanvas).
-  return typeof OffscreenCanvas === 'undefined' ?
-      document.createElement('canvas') :
-      undefined;
+  return supportsWebGL2ForOffscreenCanvas ? undefined :
+                                            document.createElement('canvas');
 }
 
 /** Base class for all MediaPipe Vision Tasks. */