javascript - 如何从内部图像onLoad返回变量

Question

  export class AttachmentComponent {
   imageWidth: number;
   imageHeight: number;
   ngOnInit() {
    this.imgSize(imagePath);
   }
   getImageSize(url) {
    const img = new Image();
    img.src = imgurl;
    img.onload = (event) => {
      const  loadedImage: any = event.currentTarget;
      const width = loadedImage.width;
      const height = loadedImage.height;
    }
   }
 }

在这里，我想填充类的“imageWidth”和“imageHeight”属性，并在getImageSize 的onLoad 中计算宽度和高度。帮助？

Answer 1

如果我对您的问题的理解是正确的，您希望将 loadImage.width 的值分配给imageWidth属性，并且与height相同。

您可以通过引用AttachmentComponent实例来做到这一点。

export class AttachmentComponent {
   imageWidth: number;
   imageHeight: number;
   ngOnInit() {
    this.imgSize(imagePath);
   }
   getImageSize(url) {
    const img = new Image();
    img.src = imgurl;
    img.onload = (event) => {
      const  loadedImage: any = event.currentTarget;
      // => here is what I've changed
      this.imageWidth = loadedImage.width;
      this.imageHeight = loadedImage.height;
    }
   }
 }