Text wrapping does not work properly for accented characters

[MartinZikmund]

Describe the bug

Text wrapping does not properly work for accented characters like ěščřžýáíé.

To Reproduce

1. Open sample app for Xamarin.Forms
2. Select Text tab
3. Enter: ščěěščž čšřžščřž čšřžščř čšřžščř čšřžščř čšřžščř čšřžščř
4. Resize the window. Notice the line breaks anywhere within the "words"

Expected behavior

Words with accented characters should not be broken between lines.

Environment (please complete the following information):

• Platform: CSharpMath.SkiaSharp (in general, not just XF)
• Package Version or Commit: latest
• Device: Windows

[Happypig375]

@prepare Probably a bug of Typography.TextBreak.

[Happypig375]

Confirmed a bug of Typography.TextBreak.

[prepare]

This Typography bug was fixed,

see => LayoutFarm/Typography@f350e22

[MartinZikmund]

@prepare Thanks a lot!

[Happypig375]

Still need to fix this for diacritics via LaTeX commands instead of Unicode, i.e. a\r aa should be one group.

[BenjaNapo]

That's what happen when I try to show chinese text (appear squares), is this relate to this issue?

[Happypig375]

You should provide your own font like in #142.

[Happypig375]

@BenjaNapo See #20.

[BenjaNapo]

@BenjaNapo See #20.

I wrote in the constructor of App.cs:
CSharpMath.Settings.GlobalTypefaces = new Typography.OpenFont.OpenFontReader().Read(File.Open("Cabin-Regular.ttf", FileMode.Open));

but it says that GlobalTypefaces is an onlyread attribute

[Happypig375]

For GlobalTypefaces, you call Add.

[BenjaNapo]

For GlobalTypefaces, you call Add.

App.xaml

           <OnPlatform x:Key="Regular" x:TypeArguments="x:String">
               <On Platform="Android" Value="Cabin-Regular.ttf#Cabin" />
               <On Platform="iOS" Value="Cabin-Regular" />
           </OnPlatform>

App.cs

       public App()
       {
           InitializeComponent();
           [... various initialization ...]
           object s = new object();
           Resources.TryGetValue("Regular", out s);
           CSharpMath.Settings.GlobalTypefaces.Add(new Typography.OpenFont.OpenFontReader().Read(s as Stream));
       }

Sorry but I never imported Font from code, where did I go wrong?

[Happypig375]

Are you trying to override the font? The default is AddSupplement. For overrides, use AddOverride.

[BenjaNapo]

Are you trying to override the font? The default is AddSupplement. For overrides, use AddOverride.

Changed with:

            object s = new object();
            Resources.TryGetValue("Regular", out s);
            Typeface t = new Typography.OpenFont.OpenFontReader().Read(s as Stream);
            CSharpMath.Settings.GlobalTypefaces.AddOverride(t);

But 3rd line throws ArgumentNullException, I think that the problem is in reading font file in this way

[Happypig375]

The null means that s is probably not a Stream. Please check.

[BenjaNapo]

        public async void LoadFont() {
            using (var stream = await FileSystem.OpenAppPackageFileAsync("Helvetica-Bold.otf"))
            {
                Typeface t = new Typography.OpenFont.OpenFontReader().Read(stream as Stream);
                CSharpMath.Settings.GlobalTypefaces.AddOverride(t);
            }
        }

Now it loads the font from the stream but crash on the 4th line (Typeface t = ...) throwing this exception:
System.NotSupportedException: 'Specified method is not supported.'

[Happypig375]

Try following https://github.com/verybadcat/CSharpMath#sourcelink-for-ci-packages and debug into the source of Typography.

[Happypig375]

@BenjaNapo Or you can upload a zipped file containing your file and let me investigate what changes are needed from Typography's side.

[Happypig375]

This bug's fix depends on a decision on updating Typography in LayoutFarm/Typography#192.
The fix for

Still need to fix this for diacritics via LaTeX commands instead of Unicode, i.e. a\r aa should be one group.

is scheduled after #143 and #58.

[BenjaNapo]

https://drive.google.com/file/d/1zlvyQ2XXvb0fQJ8k-otYZ4hiR_8L3H-d/view?usp=sharing

Here you are, with this you could note all the issues that I had 'til now (text alignment, change font and height of textview)

Thanks for all the help ^^ Hope this will contribute with the evolution of the library

[Happypig375]

@BenjaNapo #144 should fix "text alignment" and "height of textview".

This leaves "change font" as to-do.

Thanks for all the help ^^ Hope this will contribute with the evolution of the library

Thank you for taking the time to report problems too!

[Happypig375]

@BenjaNapo I can't download the file.

I have requested access.

[BenjaNapo]

I have requested access.

Ow, sorry, thought that just the link will work. Does it work now?

[Happypig375]

Works now, thanks

[Happypig375]

@BenjaNapo I'm not getting the NotSupportedException.

[BenjaNapo]

Still not working, tried as you to put the method inside async OnStart but nothing

It crash at line 53, and, as you can see, stream.Length and stream.Position are not setted, so probably the Read try to use them

[Happypig375]

What is the stack trace?

[BenjaNapo]

Do you mean this?

[Happypig375]

I mean the stack trace of the exception.

[BenjaNapo]

Ehm... How can I ?

[Happypig375]

[BenjaNapo]

As you can see I don't have the "View Details" option 🙄 Probably is because I'm working on Android device and not using UWP

[MartinZikmund]

@Happypig375 Should this be working in the latest preview NuGet package (0.5.0-alpha4) or is it not yet released?

[Happypig375]

Yes, the fix should be included in 0.5.0-alpha4.

[MartinZikmund]

@Happypig375 It seems it does not work for me 🤔 :

For example on the last line of the text is the word "světovou" broken as "svě" and "tovou". Was the Typography module bumped to the updated version?

@prepare do you have some idea what could be wrong?

[Happypig375]

Ohhh. Yea I misrecognized this issue as the ones that were fixed. Yes this depends on updating Typography currently, but I am looking to refactor to reuse the math parser for text, so the Typography.TextBreak dependency will be gone by then. This is targeted at 0.5.0-beta.

[BenjaNapo]

In the end I resolved in this way:

            Stream stream = await FileSystem.OpenAppPackageFileAsync("GTEesti-Light.ttf");
            MemoryStream ms = new MemoryStream();
            stream.CopyTo(ms);
            ms.Position = 0;
            OpenFontReader ofr = new OpenFontReader();
            Typeface t = ofr.Read(ms);
            CSharpMath.Settings.GlobalTypefaces.AddOverride(t);

[Happypig375]

Oh... Maybe the stream returned by FileSystem.OpenAppPackageFileAsync is not seekable.

[BenjaNapo]

Yep, indeed the NotSupportedException was in Length/Position attributes 😅 I think that now we can close the issue (?)

[BenjaNapo]

That's what happen when I try to show chinese text (appear squares), is this relate to this issue?

Anyway I'm still having this issue, on Label chinese text is showed (so it's a not problem of the font)...

[MartinZikmund]

Hey, I have updated to latest package (beta), but the problem seems to persist:

Also noticed the accented characters don't play well with bold/italics, is that a known issue?

[BenjaNapo]

Hey, I have updated to latest package (beta), but the problem seems to persist:

Also noticed the accented characters don't play well with bold/italics, is that a known issue?

Try to load an italic font

[charlesroddie]

Also noticed the accented characters don't play well with bold/italics, is that a known issue?

This is tracked here: #142

However it will be a few weeks before I can work on this.

[MartinZikmund]

Hi @Happypig375, regarding the line break fix for words with accented characters, is there an estimate when a preview package with this could be released please :-) ?

[Happypig375]

@MartinZikmund I don't have the capacity to put in work in the near future. It's really best to just fork and submit a PR for now.

[MartinZikmund]

@Happypig375 of course, understood 👍. Just to check - is there something missing on the text wrapping code-wise or is it just about releasing a new package? I thought @prepare adjusted the line breaks in Typography, which should transitively fix the problem for CSharpMath, if we update to that version.

[Happypig375]

See #107 (comment).

[charlesroddie]

@MartinZikmund I said I would do the font work but am not using TextPainter any more. I don't think I have time to progress with this by myself in the very near future but can collaborate with you on a PR. Weekends best.