Difference between revisions of "Qt Interface"

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Its widgetset class is in lcl/widgetset/wsbuttons.pp. This is the platform independent base for all widgetsets (qt, carbon, gtk, win32, ...).
 
Its widgetset class is in lcl/widgetset/wsbuttons.pp. This is the platform independent base for all widgetsets (qt, carbon, gtk, win32, ...).
  
Its carbon interface class is in lcl/interfaces/qt/qtwsbuttons.pp:
+
Its qt interface class is in lcl/interfaces/qt/qtwsbuttons.pp:
  
 
   TQtWSButton = class(TWSButton)
 
   TQtWSButton = class(TWSButton)

Revision as of 03:26, 12 February 2006

Introduction

The Qt 4 widgetset is in an early stage of development.

This interface is based on Qt 4.0 and it's corresponding documentation here.

Qt 4 Bindings

This interface utilizes Qt 4 bindings created by Den Jean. The bindings are a c++ library which exports the methods of the Qt objects as procedures. The library has 800kb in linux, consists of a single .so file that needs to be distributed with your LCL program.

You can find more information about those bindings on the official website.

Is is being reported that it may be possible to link to Qt 4 directly, using some tricks. Many think it is not. This is yet to be tested. It is expected that any such binding will be compatible with the currently utilized one, so the interface code won´t have to be changed.

Compiling the bindings

It is not necessary to compile the bindings yourself if you plan to release a GPL software. GPL Binaries are available on Jen Dean website. If you want to release non-GPL code, then you must compile the bindings yourself using the Commercial Edition of Qt.

Step 1 - To start with download all the files needed to compile the bindings.

  • Download the source code of the bindings. Go to this location and look for a file named qt4pas-1.02.tar.gz or similar.
  • Also Download Qt 4.0.1 source code for the desired platform. This is the download page: [1]

Step 2 - Unpack all the files you downloaded. Enter the directory where you downloaded Qt 4.0 source code and use this command:

./configure

Step 3 - Go to the directory where you downloaded and extrected qt4pas sources and edit the file compile_lib.bash. Change the path for the Qt 4.0.1 source code.

Step 4 - Run the script called compile_lib.bash. Now you should have a file called libqt4intf.so

Road map for the Qt 4 interface

currently implemented components with their status

  • TApplication - Partially implemented
  • TCustomForm - Partially implemented
  • TCustomButton - Fully implemented!
  • TCustomMemo - Partially implemented
  • TMouse - Fully implemented!
  • TCanvas - Partially implemented

components scheduled to be implemented

  • TPopUpMenu
  • TBitmap - Needs a description of the internal format used by Qt
  • TPixmap
  • TIcon

currently implemented Windows API functions by group and with status

Mouse functions

SetCursorPos, GetCursorPos for TMouse - Fully working

wish-list of new components

Use this space for components you would like to see implemented

How to add a new control

For example TButton.

TButton is defined in lcl/buttons.pp. This is the platform independent part of the LCL, which is used by the normal LCL programmer.

Its widgetset class is in lcl/widgetset/wsbuttons.pp. This is the platform independent base for all widgetsets (qt, carbon, gtk, win32, ...).

Its qt interface class is in lcl/interfaces/qt/qtwsbuttons.pp:

 TQtWSButton = class(TWSButton)
 private
 protected
 public
   class function  CreateHandle(const AWinControl: TWinControl; const AParams: TCreateParams): TLCLIntfHandle; override;
 end;

Every WS class, that actually implements something must be registered. See the initialization section at the end of the qtwsXXX.pp unit:

 RegisterWSComponent(TQtButton, TQtWSButton);

TQtWSButton overrides CreateHandle to create a qt QPushButton. The code is short and should be easily adaptable for other controls like TCheckBox. Remember that all controls on the Qt widgetset have a helper class on qtprivate.pp, and it is also necessary to add a class for the new control. This isn´t difficult.

Also notice that DestroyHandle should be implemented to clean up memory utilized by the control.