SVision2

This is SVision2. Another GUI library. A continuation of SVision for MSDOS: SVision for MSDOS.

See full source for demo - src/main.cxx

Goals

• The main goal is to be able to replace QtWidgets.
• Should be using modern idioms, and tools.
  • CMake for building.
  • Conan for package management (vcpkg support sounds nice).
  • For formatting is done using clang-format.
  • RAII (new widgets are std::make_shared<Button>)
  • Composition over inheritance, instead of nested inheritance trees, move shared behaviours into different helper classes (see src/buttonstates.h (used by Button and Checkbox).
  • Avoid using the C/C++ precompiler (no #ifdef).
  • No PIMPL. While its a nice idea, it complicates things when you want to debug.
    • C++ has no concept of ABI. Do not fight it.
    • When needed - ABI will be enforced by a set of tools that will query public APIs
  • When using platform agnostic objects:
    • By default you get one specific to your platform.
    • On Windows when you ask for Timer in practice you get a Win32Timer, and you can see on the debugger the UINT_PTR timer_id
    • On Posix (Linux/OSX/*BSD), you get a PosixTimer and you can see its timer_t timerid.
• Using "new C++ syntax": auto func() -> const int; - for everything.
• Initiailization of object is done in public (in the header, for trivial thing, instead of constructor). Always uses int foo = 0; Point location = {}. So you can look for = and know when a member is assigned by default.
• WIP: Gitlab mirror.
• TODO: For text layout - use Harfbuzz.
• TODO: This library should be a C++20 module.
• TODO: This library should be on Conan, vcpkg, etc for easy consuming.

Status

Status is that this is not usable still, and it is under heavy development.

• Linux: tested under Debian stable. Should work on any other Linux (tested only 64 bit, but 32 shoud still compile and work).
• Windows/MingGW: Tested under the default toolchain that ships with Qt 6.2.
• Windows/Clang(MSVC): Using MSVC 2019.
• This project uses conan1. conan 2 is not usable yet, as some recipes have not been ported.

For compilation instructions see Compilation instructions

• Linux instructions
• Windows/MINGW instructions
• VisualStudio instructions

OSX setup

... I don't own a Mac, so a PR is welcomed. If you want to buy me a Mac, contact me. This is planned - and should be easy to port.

Porting to new platforms

The design of this toolkit is trivial: everything is a raster image. No GPU. Each widget has its own buffer it writes to it, and it gets painted into the parents.

1. src/platform-foo.{h,cpp}: Implement a new struct PlatformFOO : Platform:
   1. open_window() returns your platform window (see bellow).
   2. invalidate(PlatformWindow &w) first cast to your own window: auto window = static_cast<PlatformWindowFOO *>(&w); (no need to validate, if someone is sending a different class on purpose - an uglier problem happens).
   3. show_window() - again, cast to your own class, to get the correct handle (platformwin32.cpp is a good simple example).
   4. invalidate() - again, cast to your own class, to get the correct handle. This paints the window content into your platform windowing system.
   5. main_loop() - note that you should not exit on last window open. See platformwin32.cpp for reference.
   6. Convert local event, keyboard events to the ones on this system. See convert_x11_key_event() as example.
   7. Add at the bottom of the header using ThePlatform = PlatformFOO.
2. PlatformWindowFOO: this class defines a new window. You can add your local code (HWND or XID). Do this internally in the PlatformFOO.cpp file - only forward declare this in the header, as this is an pure implementation detail.
3. src/timer.{h,cpp}: You will also need a platform timer. inside timer.h, add define struct FooTimer : PlatformTimer - and at the end using Timer = FooTimer.