Introduction

Virtual Treeview is a powerful Delphi component that combines fast painting with flexibility and functionality.

There's already a working Lazarus Virtual Treeview port so why redo this? The basic idea is to maintain all features of the original version that was missed in the first port. Detailed reasons here

Status

Currently the port is fully working in win32, gtk, gtk2 and Qt.

Port Guidelines

The general approach is to try to keep all features without changing much the core code.

• Only remove code if absolutely unnecessary or absolutely not portable
• Add log messages every where
• If changes are necessary then change only one subsystem at time (Painting, DragDrop etc) and than test.
• If a bug / Delphi incompatibility is found than fix or report
• Document the changes made and the Delphi/LCL differences

Port Roadmap

• Make compilable - OK
• Revise the code - OK
• Add logging infrastructure - OK
• Make work at windows - OK
• Emulate each missing winapi function (test both in win and gtk) - WIP
• Ensure all messages are working as expected
• Replace the emulated code by LCL functions
• Define how Unicode/bidi support will be done - OK
• Replace WideString by UTF-8 (The standard for LCL)
• Define Drag and Drop support
• Migrate to LCL Drag and Drop support - OK
• See how to do Drag and Drop between applications
• Convert asm code
• Maybe not necessary to convert asm if newer versions of fpc become more Delphi compatible
• Add fallback functions for architectures other than i386
• Make logging functions optional by using conditional defines
• Back port changes in the original code - OK at 29/03/2008
• Add improvements

Using the SVN Version

Requirements

• Virtual Treeview from svn
• Lazarus 0.9.26 or a recent svn
• LCLExtensions package from svn
• MultiLog 0.4 or above

Known Issues

• It was only tested in 32bit OS. Probably it won't work in 64bit OS mostly due to timer implementation that expects a 32bit THandle
• Alpha blend is working only under win32 and Qt
• It wont work with carbon interface (i don't have a Mac to develop)
• The panning window in gtk is not implemented, although the scrolling when middle mouse button is pressed works.
• Win98 requires Unicode compatibility layer to be installed. Not tested.
• Drag and drop to/from other LCL controls was not tested extensively.
• Few tests were done without known issues.
• OLE drag and drop works only in win32.

Planned changes before a full release

• Remove multilog dependency
• Fix most of the known issues
• Merge the changes done in soft-gems svn repository. OK at 29/03/2008
• The Unicode encoding will change from UTF-16 to UTF-8