huixiang_app/lib/utils/widget_util.dart

import 'dart:async';

import 'package:flutter/widgets.dart';

import 'captcha_util.dart';


/// Widget Util.
class WidgetUtil {
  ///get Widget Bounds (width, height, left, top, right, bottom and so on).Widgets must be rendered completely.
  ///获取widget Rect
  static Rect getWidgetBounds(BuildContext context) {
    RenderObject? box = context.findRenderObject();
    return (box != null) ? box.semanticBounds : Rect.zero;
  }

  ///Get the coordinates of the widget on the screen.Widgets must be rendered completely.
  ///获取widget在屏幕上的坐标,widget必须渲染完成
  static Offset getWidgetLocalToGlobal(BuildContext context) {
    RenderBox? box = context.findRenderObject() as RenderBox?;
    return box == null ? Offset.zero : box.localToGlobal(Offset.zero);
  }

  /// get image width height，load error return Rect.zero.（unit px）
  /// 获取图片宽高，加载错误情况返回 Rect.zero.（单位 px）
  /// image
  /// url network
  /// local url , package
  static Future<Rect> getImageWH(
      {required Image image, String? url, String? localUrl, String? package}) {
    if (CaptchaUtil.isEmpty(image) &&
        (url == null || CaptchaUtil.isEmpty(url)) &&
        (localUrl == null || CaptchaUtil.isEmpty(localUrl))) {
      return Future.value(Rect.zero);
    }
    Completer<Rect> completer = Completer<Rect>();
    Image img = image;
    img.image
        .resolve(const ImageConfiguration())
        .addListener(ImageStreamListener(
          (ImageInfo info, bool _) {
        completer.complete(Rect.fromLTWH(0, 0, info.image.width.toDouble(),
            info.image.height.toDouble()));
      },
      onError: (Object exception, StackTrace? stackTrace) {
        completer.completeError(exception, stackTrace);
      },
    ));
    return completer.future;
  }

  /// get image width height, load error throw exception.（unit px）
  /// 获取图片宽高，加载错误会抛出异常.（单位 px）
  /// image
  /// url network
  /// local url (full path/全路径，example："assets/images/ali_connors.png"，""assets/images/3.0x/ali_connors.png"" );
  /// package
  static Future<Rect> getImageWHE(
      {required Image image,
        String? url,
        String? localUrl,
        String? package}) {
    if (CaptchaUtil.isEmpty(image) &&
        (url == null || CaptchaUtil.isEmpty(url)) &&
        (localUrl == null || CaptchaUtil.isEmpty(localUrl))) {
      return Future.error("image is null.");
    }
    Completer<Rect> completer = Completer<Rect>();
    Image img = image;
    img.image
        .resolve(const ImageConfiguration())
        .addListener(ImageStreamListener(
          (ImageInfo info, bool _) {
        completer.complete(Rect.fromLTWH(0, 0, info.image.width.toDouble(),
            info.image.height.toDouble()));
      },
      onError: (Object exception, StackTrace? stackTrace) {
        completer.completeError(exception, stackTrace);
      },
    ));

    return completer.future;
  }
}