first look at the picture

:

2. canvas 1490px
3. 740px

2.

canvas

3.

1. vue , canvas
   ...
2. (4)

4.

1. 

2. , canvas

   

3. vue-cli, , canvas
   

   
   

   

4. add
   set the browser to non-full screen state, and then change the size of the browser. canvas elements will also return to the container

although there is a problem with the above, the first picture shows that the browser has obtained 740px

adding a delay can solve the problem, but it doesn"t feel good. I"m looking forward to a better solution

export const setCanvasWidth = that => {
  setTimeout(() => {
    const elWidthValue = that.$refs.el.offsetWidth;
    that.canvasWidth = `${elWidthValue}`; // props need String
  }, 300);
};