Canvas text vanishes when Output window opens

Anvil Q&A
1

What I’m trying to do:

Standard debugging of a form that includes Canvas objects. I created the objects programatically and set them to a color and text (via fill_text()).

Run program, text and background color look fine. Do some stuff, click on Output window, text vanishes but color is fine.

What I’ve tried and what’s not working:

Theoretically I can debug without viewing text, I just wonder why it’s happening so I don’t have to worry about the text vanishing at run time for my users.

Code Sample:

# code snippet

Clone link:
share a copy of your app
https://anvil.works/build#clone:FCK46AB5WAL7LE3E=7X4SZSJBI7C4BSBETN7DNA7B

To duplicate, Run, click Test Player. Click on a few squares. Click Output window.

Thanks,
Heidi

2

Hello there,

Have you tried searching the forum for "canvas/disappearing etc…? I have a vague memory of there being other posts on this but I’m not 100% sure.

3

I couldn’t find anything…

4

How about under “canvas resizing” or something like that. Pretty sure there is an old post that might be relevant if memory serves me correctly (which it often doesn’t!).

1 Like
5

Okay I found this: How Canvas.save() and Canvas.restore() actually work

Which shows how to save, then restore canvas if the form is resized. This is probably what happened - when the output window opened, the form resized.

But… can I capture a form.resize event? Don’t see on on the design page. So I won’t know when to trigger.

6

Ah okay I see it now! The canvas element has a resize event! Thanks for pointing me in the right direction.!

2 Likes