C++ how to use wide strings and char?

Wanderer · 18 Aug 2017, 15:26

I want multilanguage interface, how can I display widestring or char? I tried in xaml in textBlock word "prázdno", Noesis display prOzdno O = rectangle. If I add text in c++ code

NsString text = "prázdno"

in gui I get OOno O = rectangle. I dont use any theme now.

18 Aug 2017, 17:00

The font needs to have a glyph for the given codepoint.
Change the font family of your text to Robot (In Samples folder) and it'll render fine.

18 Aug 2017, 17:01

We only support UTF8 encoding. So, you need to translate from wide string to UTF8. In windows you can use WideCharToMultiByte and similar functions for that purpose. We also provide a portable function inside UTF8.h.

/// Conversion from UTF16 to UTF8. Returns the numbers of characters needed for the whole text
/// even if they don't fit in the provided buffer.
inline NsSize UTF16To8(const NsUInt16* utf16, NsChar* utf8, NsSize numUTF8Chars);

Please, let me know if this solves your problem.

18 Aug 2017, 17:07

The font needs to have a glyph for the given codepoint.
Change the font family of your text to Robot (In Samples folder) and it'll render fine.

Indeed you also need a compatible font. Thanks Athos!

Wanderer · 19 Aug 2017, 10:47

Thanks all for answers. I resolve conversion myself and it is working (using Poco library for text).

I have another questions:
1. When I set up Theme(with ResourceDirectory) and ResourceProvider, how this theme knows where is font located? I checked xaml files but don't find any info how is used font. In tutorials is mentioned only for TextBlock but how use one font for all text?

2. When I have this code

const NsChar * ContainerItem::m_func_GetNameSource() const // is part Noesis Get and Set function for displaying text in GUI by binding
{
	std::wstring ws = L"ľščť";
	std::string text;
	Poco::UnicodeConverter uc;
	uc.toUTF8(ws, text);
	NsString m_NsString_SourceFull = text.c_str();
	return m_NsString_SourceFull.c_str();
}

Program freezes - window appear but nothing is shown. If m_NsString_SourceFull is created with text

NsString m_NsString_SourceFull = "ľščť";

program start ok. But characters are not show right. The best solution I found is m_NsString_SourceFull must be member and make conversion outside GetNameSource() method. Then program never freezes. Question is, why I cannot have conversion inside GetNameSource()?

19 Aug 2017, 21:51

In your code m_NsString_SourceFull in getter function is a stack variable, a temporal object, so returning c_str() of that object may result in a crash or accessing corrupted memory.
You should declare it as a member variable, so object persists after returning from the function, something like this:

class YourViewModel: Noesis::BaseComponent ...
{
public:
  ...
  const NsChar* ContainerItem::m_func_GetNameSource() const
  {
	std::wstring ws = L"ľščť";
	std::string text;
	Poco::UnicodeConverter uc;
	uc.toUTF8(ws, text);
	m_NsString_SourceFull = text.c_str();
	return m_NsString_SourceFull.c_str();
  }
  ...
private:
  NsString m_NsString_SourceFull;
  ...
};

Wanderer · 20 Aug 2017, 18:59

Thanks.

23 Aug 2017, 20:14

About the global font, we have a default ttf that is applied when nothing else is specified.

If you want to specify your own global font there are two ways of doing it:

- In the Theme, by defining a ContentControl style with the key RootContainerStyle. If that key is found in the Theme dictionary we wrap View content with a ContentControl and apply that style so everything inherits all the properties set in the style. It could look like this:

<Style x:Key="RootContainerStyle" TargetType="{x:Type ContentControl}">
    <Setter Property="UseLayoutRounding" Value="True"/>
    <Setter Property="Foreground" Value="Black"/>
    <Setter Property="FontFamily" Value="Fonts/#Roboto"/>
    <Setter Property="FontSize" Value="12"/>
    <Setter Property="FontStyle" Value="Normal"/>
    <Setter Property="FontWeight" Value="Normal"/>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type ContentControl}">
                <ContentPresenter/>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

- Setting these properties in the root of your View yourself. You can create the View with a UserControl root object that will be the container for all your UI. UI elements will inherit all the properties you set in the root UserControl:

<UserControl
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  UseLayoutRounding="True"
  Foreground="Black"
  FontFamily="Fonts/#Roboto"
  FontSize="12"
  FontStyle="Normal"
  FontWeight="Normal">
    <!--- UI will be added as Content of this control -->
</UserControl>

Wanderer · 23 Aug 2017, 23:01

Thanks.

If I use both scenario, which fonts will be used? Can I overide theme font by adding this:

<UserControl
  ...
  FontFamily="Fonts/#Roboto"
  FontSize="12"
  FontStyle="Normal"
  FontWeight="Normal">
    <!--- UI will be added as Content of this control -->
</UserControl>

it is possible?

24 Aug 2017, 11:45

Yes, you can override it like this, because inherited properties like FontFamily, FontSize, Foreground, etc. use the value set in the nearest ancestor.

C++ how to use wide strings and char?

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