feat: Screenshooting of web elements (#2499)

lib/commands/screenshots.js

@@ -78,13 +78,19 @@ export default {
     el = util.unwrapElement(el);
     if (this.isWebContext()) {
       const atomsElement = this.getAtomsElement(el);
-      return await this.executeAtom('getElementScreenshot', [atomsElement]);
+      const {width, height} = await this.executeAtom('get_size', [atomsElement]);
+      if (!width || !height) {
+        throw new errors.UnableToCaptureScreen('Cannot take a screenshot of a zero-size element');
+      }
+      const {x, y} = await this.executeAtom('get_top_left_coordinates', [atomsElement]);
+      return await (/** @type {import('appium-remote-debugger').RemoteDebugger} */ (this.remote))
+        .captureScreenshot({rect: {x, y, width, height}});
     }
 
     const data = await this.proxyCommand(`/element/${el}/screenshot`, 'GET');
     if (!_.isString(data)) {
-      this.log.errorAndThrow(
-        `Unable to take a screenshot of the element ${el}. WDA returned '${JSON.stringify(data)}'`,
+      throw new errors.UnableToCaptureScreen(
+        `Unable to take an element screenshot. WDA returned: ${JSON.stringify(data)}`,
       );
     }
     return data;