XamlCpp

An implementation of XAML cross-platform framework for C/C++.

This project is NOT complete, and still needs a lot of work. Welcome issues and pull requests!

Goal

The goal of XamlCpp is to write a cross-platfrom and cross-language* GUI application easily and quickly. It uses a dialect of XAML to discribe the UI, but may not support all features like other XAML frameworks do. The final application should be tiny, with a few dependencies.

* At first, I only want to target C++, and that's why it is called XamlCpp. Now it also targets C, with Rust and C#, in principle.

Charset

XamlCpp uses UTF-8 everywhere, which is ensured by a modified version of boost-nowide on Windows.

Object Model and Reflection

The object model of XamlCpp is inspired by COM. But there are some difference:

• COM uses stdcall for standard calling convention, while XamlCpp uses cdecl on Windows.
• In most cases, COM needs a server to manage the classes and memory, but XamlCpp needs not.
• COM distinguishes classes and interfaces. XamlCpp only provides interfaces, and the implementations could only be constructed by specified functions.
• COM uses PascalName, while XamlCpp uses snake_name.

But there are many more similarities. For example, the definition of xaml_result is the same as HRESULT, and even the value means the same; both of them don't use exceptions; the object model looks like the same, and some GUIDs of primitive types is the same as .NET(which WAS COM+ at first).

Writing a class for XamlCpp is more complicated than a normal C++ class, but simpler than COM. You don't need idl files and non-standard keywords, but predefined helper macros. Such a definition of the interface could be easily projected to C, Rust and C#, which means different languages could cooperate (maybe not that?) easily.

XamlCpp supports reflection by this object model. All registered class could be constructed dynamically, and methods, properties and events registered could be accessed dynamically. Note that reflection is not free nor type-secure. Programmers are responsible for the cost and type checking, and any type mismatch is undefined behavior.

A simple example is here.

GUI

XamlCpp is a cross-platform GUI framework. With some simple, platform-specific work, you can make your application run on all platforms supported.

An example is here

GUI is divided into several parts. The basic UI project is responsible for the main loop, windows and system dialogs. It is necessary to run a GUI application.

Screenshots

Platform	Light	Dark
Win32
GTK+3
QT5
Cocoa

* Due to API limitation, dark mode for Win32 is not completed.

** Screenshots of Gtk and Qt is captured on KDE with theme Breeze.

UI

It supports desktop environment with concepts of "window" and "screen", and many dialogs like "message box" and "file box". It also supports high DPI settings even on Windows.

Supported platforms

Name	API set	Supported OS	Recommanded OS
Win32	Windows API	Windows*	Windows
GTK+3	GLib, Gdk, Gtk	Windows, Linux, MacOS	Windows/MinGW64, Linux
QT5	Qt5Widgets	Windows, Linux, MacOS	Windows, Linux, MacOS
Cocoa	Cocoa	MacOS	MacOS

* At least Windows 7.

Controls

Common controls, works on all platforms.

Canvas

A canvas control.

Supported platforms

Name	API set
Win32	Direct2D
GTK+3	Cairo
QT5	QPainter
Cocoa	NSGraphicsContext

WebView

A webview control.

Supported platforms

Name	API set
Win32	Edge(Chromium) -> Edge -> IE *
GTK+3	Webkit **
QT5	Qt5WebEngine or Qt5WebKit ***
Cocoa	WebKit

* Indicates the search order. IE is supported to ensure it could be used.

** Linux only because of the limitation of webkit2gtk.

*** Could be specified in configuration.

XAML

XamlCpp uses a dialect of XAML, which may support XAML Standard in the future. XAML files are either interpreted at run-time, or compiled to C++ code at compile-time.

Here's an XAML example:

<window xmlns="https://github.com/Berrysoft/XamlCpp/"
        xmlns:x="https://github.com/Berrysoft/XamlCpp/xaml/"
        title="Test Window" location="200, 100" size="800, 600">
  <grid margin="10" columns="1*, 0.8*, 1*" rows="1*, auto, 1*">
    <label x:name="mylabel" grid.column="0" grid.row="1" margin="5, 0" text_halignment="right" valignment="center" text="{binding text,element=mybutton,mode=one_way}"/>
    <button x:name="mybutton" grid.column="1" grid.row="1" click="on_button_click">Hello</button>
    <canvas grid.column="0" grid.row="2" margin="10" redraw="on_canvas_redraw"/>
  </grid>
</window>

The xmlns should be https://github.com/Berrysoft/XamlCpp/ to use default controls. The xml attributes decribes the properties, events and attach properties of a control.

The XAML parser uses a modified version of rapidxml_ns. It is modified to use features of C++ 17 and simplified to support UTF-8 only for convenience.

Detector

XamlCpp provides a detector called xmald to show the reflection information of a dynamic library for XamlCpp.

Resource

XamlCpp provides a resource compiler called xamlrc, to embed small files into the final program. It supports UTF-8 only.

Build

A C++17-compliant compiler is required. Actually it needs C++ 20, but no compiler is compliant...

This project assumes it is built by MSVC 19.27+, GCC 10.0+ or Clang 10.0+.

boost is required on all platforms for cmdline.

Build for Win32

wil is required. Other packages will be downloaded from NuGet when configuring.

Build for GTK+3

MSVC

gtk is required.

MinGW64 & Linux & MacOS

gtk and pkgconfig are required. webkit2gtk is also required on Linux for webview.

Build for QT5

qt5-base is required. Either qt5-webengine or qt5-webkit is also required for webview.

Build for Cocoa

No other package is needed.