With flex box and column direction, the height increases but does not reduce
Ajust the size of the result box at
https://codepen.io/tofnet/pen/BaoqQgB
display: flex; flex-direction: column;
You are allowing overflow. Add overflow: hidden to the container's style.
Thank you for this quick return, the flex column problem is solved with overflow hidden.
Sorry my example is bad and the problem I am having would come from flex wrap.
I updated the codepen : https://codepen.io/tofnet/pen/vYNVXNK
Any idea or I make a mistake with the css again?
Would not go that far as blaming you for a mistake.
But again it can be worked around; By positioning the canvas absolutely - so it will not grow its parent: https://codepen.io/kurkle/pen/dyYgRab
Nice! I learned something. Thanks Kurkle