String concatenation with special character

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1

I'm having a super strange problem when concatenating strings that contain the ™ character. I'm iterating through words of a string and inserting a new line \n when it gets too long. If the ™ is present in the string before the line break, it renders one invalid character and one misplaced characters. For example:

a test string: "™ 1test 2test 3test 4test 5test 6test 7test 8verylongtestword"
is changed to: "™ 1test 2test 3test 4test 5test 6test 7test\n8verylongtestword"
and rendered as:

Screen Shot 2020-05-26 at 12.17.20 PM
Screen Shot 2020-05-26 at 12.17.20 PM896×100 6.96 KB

This behavior is the same whether I use \n or \010 for the new line. And without the ™ before the break, it renders as expected!

I've been trying to figure out how playdate handles these few allowed unicode characters, but I'm not having much luck. Any advice?

2

I suspect the string is using UTF-8 when the sign is used.

Sorry I don't have the SDK at hand right now but can you check the length of the string with and without ™ ?

string.len("™ 1test")
string.len("A 1test")

Which method are you using to insert the linebreak?

3

Sure! I'm measuring pixel length instead of character count because I think my font isn't monospaced. So get the length I'm using playdate.graphics.getTextSize(string)

both "™ 1test" and "A 1test" have a length of 51. ". 1test" has a length of 43.

To insert the linebreak I'm using

concatString = concatString .. "\n"

4

What about character counts? That would confirm Nic's UTF-8 theory.

5

ah, I see what you meant now. Yes I can confirm it's using UTF-8

"™ 1test" length: 9
"A 1test" length: 7

Does this mean I need to do something different for line breaks?

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6

ok after some testing I would say this is probably a SDK bug and it has nothing to do with you concatenating some strings

You can see the bug just like that

playdate.graphics.drawText("™ Some Text \nNew line text", 0, 0)
playdate.graphics.drawText("A Some Text \nNew line text ™", 0, 80)

@SamanthaZero do you want to file a bug? otherwise I can do it, it's up to you.

7

If you don't mind, go ahead! You seem more confident and I trust you would know :slight_smile: And I appreciate your help!

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