How do you determine if Pen Input is blank?

[Shanescows]

I want to have a pen input to collect a signature and I only want to show the user the submit button after they have signed the form. 

How do I check if they have scribbled something in the box or not?

Thanks

Shane

[timl]

Hi Shane

Here's a formula you can use:

IsBlank(PenInput1.Strokes)

This will return false when a user scribbles something in the box.

To carry out this task, you can set the DisplayMode property of your submit button to this:

If(IsBlank(PenInput1.Strokes), 
   DisplayMode.Disabled, 
   DisplayMode.Edit
)

[Shanescows]

Hi TimL

I tried that and it doesn't work. Best I can tell there is no value stored in .Strokes 

I tried adding the code to the button and it stays disabled.

I also added a Label and set the text to Signature.Strokes and nothing shows. (I named my pen input Signature and it autocompletes without issue.)

Finally tested the app on my phone just to make sure my computer wasn't being dumb. No dice.

Thanks for any thoughts

Shane

[Shanescows · Accepted solution]

I did some messing around and the best workaround I have come up with is to see if the image URL has changed. Hopefully, someone has something better. Here is what I did:

1. Set the Screen OnVisible property to: 

UpdateContext({BlankImage: Signature.Image})

2. Set the DisplayMode of my consent button to 

If(BlankImage = Signature.Image,DisplayMode.Disabled,DisplayMode.Edit)

3. Set the OnSelect of my consent button to 

Office365.SendEmail("shane.young@boldzebras.com","My Consent Form" , "Body Text",{Attachments:Table({Name:"peninput.jpg",ContentBytes:PenInput1.Image , '@odata.type':""})});UpdateContext({BlankImage: Signature.Image})

I reset the variable to disable the button again so I can collect a new sig. Will add code to clear the other fields also.

If you didn't catch it earlier Signature is what I renamed my PenInput field to.

If anyone has a better solution I am all ears. I don't love this but I think it works.

Thanks

Shane

[Shanescows]

Sorry to keep replying to myself. 🙂 

I made this into a video. Conditional Formatting with the Pen Input

I hope it helps.

Shane

[patrickabel]

@Shanescows any luck finding a less cumbersome solution?

The absense of a value on .Strokes has got to be a bug. **bleep**'s unfortuante that the simplest of validation isn't doable without image comparisons at this point.

[timl]

Hi all,

I'm a bit confused. For me, .Strokes returns a value when I scribble into the control. When the pen input control is empty, .Strokes returns blank.

Is there something that I'm misunderstanding here, or is my version of PowerApps behaving differently to everyone else?

[patrickabel]

I can do another test to confirm, but this did not work for me after incorporating into a rule which shows/hides a button.

IsBlank(PenInput1.Strokes)

 I ended up leveraging an image compare as @Shanescows recommended.

[timl]

Hi @patrickabel

Thanks for the clarification. It's curious because I can use .Strokes as I'd expect to in a rule. Here for example, I'm able to show the button only when the pen input control contains data.

 

[Anonymous]

Hi Shane,

Thank you for your solution, the YouTube video was very helpful also.

How would you ammend the string so that it looks at two signature fields?

(Assuming Signature1 and Signature2)

Thank you

Kind regards