when deleting or backspacing with cursor at column 0, an exception is raised

[dyze]

Hi again,

I tried to use your control in immediate mode, I mean that for each tick I set my text, I call Render() and I get the text thru AllText property.
Unfortunately, in that mode, when I delete or backspace with cursor at column 0, the exception below is raised:

Can you do something for that?

Or maybe it is not attended at all to set and get AllText at each tick?

In fact, I'm doing that to be able to detect any change done in code when user types. Is there another way to proceed?

Regards

[dyze]

In fact, I solved the issue by commenting the set of AllText for each tick as below:

// once:
var editor = new TextEditor()
{
    AllText = myText,
    SyntaxHighlighter = new GlSlStyleHighlighter()
};
// ...
// and then for each tick:
// textEditor.AllText = myText;      // <= the line that causes the exception when backspacing at cursor position 0
textEditor.Render("EditWindow");
myText =  textEditor.AllText;

But I'm still interested having your feedback and especially about the way to detect changes done on text. Because today, for each tick I'm doing a string compare which is maybe not good for very long text.

cheers

[csinkers]

Yeah, you definitely don't want to be retrieving AllText on each frame - it will cause a lot of memory allocations, extra garbage collections etc. I think the easiest way to allow dirty state detection will be if I add a Version property on TextEditor that gets incremented every time the text changes, then you can do something like:

readonly TextEditor _textEditor;
long _lastVersion = -1;

void SomeFunctionCalledEveryTick()
{
    _textEditor.Render("EditWindow");

    if (_textEditor.Version != _lastVersion)
    {
        _lastVersion = _textEditor.Version;
        myText = textEditor.AllText;
    }
}

[dyze]

Thanks for your quickly answer.
Your proposal is good.
And what about exposing an Event which is maybe more close to c# principes?
It depends on the philosophy you followed so far with you control.
Regards

[csinkers]

Actually given it's an ImGui control, the best way would be to change Render so it returns bool. If it returns true, then you know the user's keyboard/mouse input modified the text.

so your code becomes even simpler:

void SomeFunctionCalledEveryTick()
{
    if (_textEditor.Render("EditWindow"))
    {
        myText = textEditor.AllText;
    }
}

[dyze]

Cool.
It is even better indeed.

[csinkers]

@dyze I've pushed a new version with the fixes so far to NuGet, it should show up in 15 mins or so. I'll keep this job open until I get a chance to investigate the exception when setting AllText.

[dyze]

Hi,
I've tried the new package. It works as expected, returned value and Version field are properly fed.
Thank you, I can remove my nasty string comparison.