Intuition window goes OOP(ish)
Revision as of 19:01, 1 April 2017 by Molly (talk | contribs) (→Dispatching messages: change title)
A long while ago, someone on the aros-exec forums suggested/asked to use some (more) OOP to create f.i. native Intuition Windows.
Although that is fairly easy to accomplish, there never was an actual example showing how to do such a thing for those wanting to have a look. So, here we go :-)
Do note however, that the code showed herein is not complete, nor does it show good programing practice (even far from it). It is merely shown as a possible solution to the problem. Much more abstraction is required in order to be able to make practical use of the implementation as showed.
Step 1: A starting point
In order to be able to show the reader how things are accomplished, we have to start with at least some bit of code. So, let's start out with a simple intuition window example. This example was taken from (and is copyrighted by) Thomas Rapp.
program Step1_SimpleWindow;
{$MODE OBJFPC}{$H+}
Uses
Exec, AGraphics, Intuition, InputEvent, Utility;
Function AsTag(tag: LongWord): LongInt; inline;
begin
Result := LongInt(tag);
end;
//*-------------------------------------------------------------------------*/
//* */
//*-------------------------------------------------------------------------*/
procedure print_text(rp: PRastPort; x: LongInt; y: LongInt; txt: PChar);
begin
GfxMove(rp, x, y);
SetABPenDrMd(rp, 1, 0, JAM2);
GfxText(rp, txt, strlen(txt));
ClearEOL(rp);
end;
//*-------------------------------------------------------------------------*/
//* Main routine */
//*-------------------------------------------------------------------------*/
function main: integer;
var
win : PWindow;
cont : Boolean;
msg : PIntuiMessage;
buffer : String[80];
begin
win := OpenWindowTags( nil,
[
AsTag(WA_Left) , 100,
AsTag(WA_Top) , 100,
AsTag(WA_Width) , 250,
AsTag(WA_Height) , 150,
AsTag(WA_Flags) , AsTag(WFLG_CLOSEGADGET or WFLG_DRAGBAR or WFLG_DEPTHGADGET or WFLG_ACTIVATE or WFLG_GIMMEZEROZERO or WFLG_NOCAREREFRESH or WFLG_RMBTRAP or WFLG_REPORTMOUSE),
AsTag(WA_IDCMP) , AsTag(IDCMP_CLOSEWINDOW or IDCMP_MOUSEMOVE or IDCMP_MOUSEBUTTONS),
TAG_END
]);
if Assigned(win) then
begin
cont := TRUE;
while (cont) do
begin
WaitPort(win^.UserPort);
while true do
begin
msg := PIntuiMessage(GetMsg(win^.UserPort));
if not Assigned(msg) then break;
case (msg^.IClass) of
IDCMP_CLOSEWINDOW:
cont := FALSE;
IDCMP_MOUSEMOVE:
begin
WriteStr(buffer, 'Mouseposition: x=', msg^.MouseX, ' y=', msg^.MouseY, #0);
print_text(win^.RPort, 10, 30, @buffer[1]);
end;
IDCMP_MOUSEBUTTONS:
case (msg^.Code) of
IECODE_LBUTTON : print_text(win^.RPort, 10, 60, 'Left mousebutton pressed');
IECODE_LBUTTON or IECODE_UP_PREFIX : print_text(win^.RPort, 10, 60, 'Left mousebutton released');
IECODE_RBUTTON : print_text(win^.RPort, 10, 90, 'Right mousebutton pressed');
IECODE_RBUTTON or IECODE_UP_PREFIX : print_text(win^.RPort, 10, 90, 'Right mousebutton released');
end;
end; // case
ReplyMsg(pMessage(msg));
end;
end; // while
CloseWindow(win);
end;
result := (0);
end;
begin
ExitCode := Main;
end.
The code itself doesn't do anything particularly difficult to understand. It opens a Intuition Window and processes the IDCMP messages and based on those messages give some feedback to the user.
The AsTag function is there for our convenience, and which is missing from FPC 3.0.x compiler (it is present for FPC 3.1.1 trunk compiler)
Step 2: Classify the window
So, now the question becomes: how do we turn the previous example into a Free Pascal Class ?
Therefor we have to take a look at some of the used properties.
We can see that opening an Intuition window returns us a pointer to the created window (handle), and that this pointer is also used to close the window again. So for these basics we at least requires a handle variable for our window and a open() and close() method.
When the window is created with OpenWindowTags() we can see that some tags are provided such as the placement of the window (left and top) and the dimensions of the window (width and height). Also a title is provided as a tag.
We turn all these into private variables and add properties for them in our class.
We put the code for our newly created class into a separate unit, so that things can be re-used with more convenience.
unit Step2_IntWinClass;
{$MODE OBJFPC}{$H+}
interface
uses
Intuition;
type
TIntuitionWindowClass = class
private
FHandle : PWindow;
FLeft : LongInt;
FTop : LongInt;
FWidth : LongInt;
FHeight : LongInt;
FTitle : String;
protected
public
Constructor Create;
Destructor Destroy; override;
public
procedure Open;
procedure Close;
public
property Left : LongInt read FLeft write FLeft;
property Top : LongInt read FTop write FTop;
property Width : LongInt read FWidth write FWidth;
property Height: LongInt read FHeight write FHeight;
property Title : String read FTitle write FTitle;
property Handle : PWindow read FHandle;
end;
implementation
uses
SysUtils;
Function AsTag(tag: LongWord): LongInt; inline;
begin
Result := LongInt(tag);
end;
procedure error(Const msg : string);
begin
raise exception.create(Msg) at
get_caller_addr(get_frame),
get_caller_frame(get_frame);
end;
Constructor TIntuitionWindowClass.Create;
begin
Inherited;
end;
Destructor TIntuitionWindowClass.Destroy;
begin
inherited;
end;
procedure TIntuitionWindowClass.Open;
begin
FHandle := OpenWindowTags( nil,
[
AsTag(WA_Left) , FLeft,
AsTag(WA_Top) , FTop,
AsTag(WA_Width) , FWidth,
AsTag(WA_Height) , FHeight,
AsTag(WA_Title) , PChar(FTitle),
// Non use settable flags (for now)
AsTag(WA_Flags) , AsTag(WFLG_CLOSEGADGET or WFLG_DRAGBAR or WFLG_DEPTHGADGET or WFLG_ACTIVATE or WFLG_GIMMEZEROZERO or WFLG_NOCAREREFRESH or WFLG_RMBTRAP or WFLG_REPORTMOUSE),
AsTag(WA_IDCMP) , AsTag(IDCMP_CLOSEWINDOW or IDCMP_MOUSEMOVE or IDCMP_MOUSEBUTTONS),
TAG_END
]);
if not Assigned(FHandle) then Error('Unable to Open Window');
end;
procedure TIntuitionWindowClass.Close;
begin
if Assigned(FHandle)
then CloseWindow(FHandle)
else Error('Unable to Close Window because the handle is invalid');
end;
end.
As you can see we've also added a constructor (Create) which initializes some default values for the FHandle and private window dimension variables as well as clear the private title variable.
We've added a destructor (Destroy) that doesn't do anything useful atm, and is there just in case we need it (we can always remove it later on)
Other then that we've added two methods, one to Open the Intuition Window and one to Close the Intuition Window and added code that actually perform these actions.
Now, we're going to make use of this new class and create a new program:
program Step2_ClassWindow;
{$MODE OBJFPC}{$H+}
uses
Step2_IntWinClass, Exec, AGraphics, Intuition, InputEvent;
//*-------------------------------------------------------------------------*/
//* */
//*-------------------------------------------------------------------------*/
procedure print_text(rp: PRastPort; x: LongInt; y: LongInt; txt: PChar);
begin
GfxMove(rp, x, y);
SetABPenDrMd(rp, 1, 0, JAM2);
GfxText(rp, txt, strlen(txt));
ClearEOL(rp);
end;
//*-------------------------------------------------------------------------*/
//* Main routine */
//*-------------------------------------------------------------------------*/
function main: integer;
var
Window1 : TIntuitionWindowClass;
cont : Boolean;
msg : PIntuiMessage;
buffer : String[80];
begin
Window1 := TIntuitionWindowClass.Create;
Window1.Left := 10;
Window1.Top := 20;
Window1.Height := 200;
Window1.Width := 320;
Window1.Title := 'This is window 1';
Window1.Open;
WaitPort(Window1.Handle^.UserPort);
cont := TRUE;
while (cont) do
begin
while true do
begin
msg := PIntuiMessage(GetMsg(Window1.Handle^.UserPort));
if not Assigned(msg) then break;
case (msg^.IClass) of
IDCMP_CLOSEWINDOW:
cont := FALSE;
IDCMP_MOUSEMOVE:
begin
WriteStr(buffer, 'Mouseposition: x=', msg^.MouseX, ' y=', msg^.MouseY, #0);
print_text(Window1.Handle^.RPort, 10, 30, @buffer[1]);
end;
IDCMP_MOUSEBUTTONS:
case (msg^.Code) of
IECODE_LBUTTON : print_text(Window1.Handle^.RPort, 10, 60, 'Left mousebutton pressed');
IECODE_LBUTTON or IECODE_UP_PREFIX : print_text(Window1.Handle^.RPort, 10, 60, 'Left mousebutton released');
IECODE_RBUTTON : print_text(Window1.Handle^.RPort, 10, 90, 'Right mousebutton pressed');
IECODE_RBUTTON or IECODE_UP_PREFIX : print_text(Window1.Handle^.RPort, 10, 90, 'Right mousebutton released');
end;
end; // case
ReplyMsg(pMessage(msg));
end;
end;
Window1.Close;
Window1.Free;
result := (0);
end;
begin
ExitCode := Main;
end.
Also here, no real rocket science. We have to take care of Creating and Destroying our class and we've replaced the 'normal' code that opened and closed the intuition Window by calling the Methods that we've just implemented. The message handling itself is still part of our main program.
Step 3: Moving around message handling
We're going to add to our class again, by moving the message handling from our main program to our class.
unit Step3_IntWinClass;
{$MODE OBJFPC}{$H+}
interface
uses
Intuition;
type
TIntuitionWindowClass = class
private
FHandle : PWindow;
FLeft : LongInt;
FTop : LongInt;
FWidth : LongInt;
FHeight : LongInt;
FTitle : AnsiString;
protected
public
Constructor Create;
Destructor Destroy; override;
public
procedure Open;
procedure Close;
procedure HandleMessages;
public
property Left : LongInt read FLeft write FLeft;
property Top : LongInt read FTop write FTop;
property Width : LongInt read FWidth write FWidth;
property Height: LongInt read FHeight write FHeight;
property Title : String read FTitle write FTitle;
property Handle : PWindow read FHandle;
end;
implementation
uses
SysUtils, Exec, AGraphics, InputEvent;
Function AsTag(tag: LongWord): LongInt; inline;
begin
Result := LongInt(tag);
end;
procedure error(Const msg : string);
begin
raise exception.create(Msg) at
get_caller_addr(get_frame),
get_caller_frame(get_frame);
end;
Constructor TIntuitionWindowClass.Create;
begin
Inherited;
FHandle := nil;
FLeft := 10;
FTop := 10;
FHeight := 30;
FWidth := 30;
FTitle := '';
end;
Destructor TIntuitionWindowClass.Destroy;
begin
inherited;
end;
procedure TIntuitionWindowClass.Open;
var
aTitle : PChar;
begin
if FTitle <> '' then aTitle := PChar(FTitle) else aTitle := nil;
FHandle := OpenWindowTags( nil,
[
AsTag(WA_Left) , FLeft,
AsTag(WA_Top) , FTop,
AsTag(WA_Width) , FWidth,
AsTag(WA_Height) , FHeight,
AsTag(WA_Title) , aTitle,
// Non use settable flags (for now)
AsTag(WA_Flags) , AsTag(WFLG_CLOSEGADGET or WFLG_DRAGBAR or WFLG_DEPTHGADGET or WFLG_ACTIVATE or WFLG_GIMMEZEROZERO or WFLG_NOCAREREFRESH or WFLG_RMBTRAP or WFLG_REPORTMOUSE),
AsTag(WA_IDCMP) , AsTag(IDCMP_CLOSEWINDOW or IDCMP_MOUSEMOVE or IDCMP_MOUSEBUTTONS),
TAG_END
]);
if not Assigned(FHandle) then Error('Unable to Open Window');
end;
procedure TIntuitionWindowClass.Close;
begin
if Assigned(FHandle)
then CloseWindow(FHandle)
else Error('Unable to Close Window because the handle is invalid');
end;
procedure print_text(rp: PRastPort; x: LongInt; y: LongInt; txt: PChar);
begin
GfxMove(rp, x, y);
SetABPenDrMd(rp, 1, 0, JAM2);
GfxText(rp, txt, strlen(txt));
ClearEOL(rp);
end;
procedure TIntuitionWindowClass.HandleMessages;
var
cont : Boolean;
msg : PIntuiMessage;
buffer : String[80];
begin
cont := TRUE;
while (cont) do
begin
WaitPort(FHandle^.UserPort);
while true do
begin
msg := PIntuiMessage(GetMsg(FHandle^.UserPort));
if not Assigned(msg) then break;
case (msg^.IClass) of
IDCMP_CLOSEWINDOW:
cont := FALSE;
IDCMP_MOUSEMOVE:
begin
WriteStr(buffer, 'Mouseposition: x=', msg^.MouseX, ' y=', msg^.MouseY, #0);
print_text(FHandle^.RPort, 10, 30, @buffer[1]);
end;
IDCMP_MOUSEBUTTONS:
case (msg^.Code) of
IECODE_LBUTTON : print_text(FHandle^.RPort, 10, 60, 'Left mousebutton pressed');
IECODE_LBUTTON or IECODE_UP_PREFIX : print_text(FHandle^.RPort, 10, 60, 'Left mousebutton released');
IECODE_RBUTTON : print_text(FHandle^.RPort, 10, 90, 'Right mousebutton pressed');
IECODE_RBUTTON or IECODE_UP_PREFIX : print_text(FHandle^.RPort, 10, 90, 'Right mousebutton released');
end;
end; // case
ReplyMsg(pMessage(msg));
end;
end;
end;
end.
The message handling is performed by our newly added method HandleMessages and as you can see the code is literally the code that was used in the main program before.
Now we have to make our main program make use of this new method.
program Step3_ClassWindow;
{$MODE OBJFPC}{$H+}
uses
Step3_IntWinClass, Exec, AGraphics, Intuition, InputEvent;
//*-------------------------------------------------------------------------*/
//* Main routine */
//*-------------------------------------------------------------------------*/
function main: integer;
var
Window1 : TIntuitionWindowClass;
begin
Window1 := TIntuitionWindowClass.Create;
Window1.Left := 10;
Window1.Top := 20;
Window1.Height := 200;
Window1.Width := 320;
Window1.Title := 'This is window 1';
Window1.Open;
Window1.HandleMessages;
Window1.Close;
Window1.Free;
result := (0);
end;
begin
ExitCode := Main;
end.
Easy enough, and things still work. A bit awkward perhaps, but it works (for this one window).
Step 4: Dispatching messages
Here is where things become a bit more interesting, as we're going to add a (IDCMP) message dispatcher to our class.
unit IntWinClass;
{$MODE OBJFPC}{$H+}
interface
uses
Intuition;
type
TIntuitionMessageRec = record
MsgCode : DWord;
IMsg : PIntuiMessage;
end;
type
TOnCloseWindowProc = procedure(var DoClose: boolean);
TOnMouseMoveProc = procedure(const IMsg: PIntuiMessage);
TOnMouseButtonsProc = procedure(const IMsg: PIntuiMessage);
TIntuitionWindowClass = class
private
FHandle : PWindow;
FLeft : LongInt;
FTop : LongInt;
FWidth : LongInt;
FHeight : LongInt;
FTitle : AnsiString;
FStopped : boolean;
FOnCloseWindow : TOnCloseWindowProc;
FOnMouseMove : TOnMouseMoveProc;
FOnMouseButtons : TOnMouseButtonsProc;
protected
procedure MsgCloseWindow(var msg: TIntuitionMessageRec); Message IDCMP_CLOSEWINDOW;
procedure MsgMouseMove(var msg: TIntuitionMessageRec); Message IDCMP_MOUSEMOVE;
procedure MsgMouseButtons(var msg: TIntuitionMessageRec); Message IDCMP_MOUSEBUTTONS;
public // creator/destructor
constructor Create;
destructor Destroy; override;
public // methods
procedure Open;
procedure Close;
procedure HandleMessages;
procedure DefaultHandler(var message); override;
public // properties
property Left : LongInt read FLeft write FLeft;
property Top : LongInt read FTop write FTop;
property Width : LongInt read FWidth write FWidth;
property Height : LongInt read FHeight write FHeight;
property Title : String read FTitle write FTitle;
property Handle : PWindow read FHandle;
public // events
property OnCloseWindow : TOnCloseWindowProc read FOnCloseWindow write FOnCloseWindow;
property OnMouseMove : TOnMouseMoveProc read FOnMouseMove write FOnMouseMove;
property OnMouseButtons : TOnMouseButtonsProc read FOnMouseButtons write FOnMouseButtons;
end;
implementation
uses
SysUtils, Exec, AGraphics, InputEvent;
function AsTag(tag: LongWord): LongInt; inline;
begin
Result := LongInt(tag);
end;
procedure error(Const msg : string);
begin
raise exception.create(Msg) at
get_caller_addr(get_frame),
get_caller_frame(get_frame);
end;
Constructor TIntuitionWindowClass.Create;
begin
Inherited;
FHandle := nil;
FLeft := 10;
FTop := 10;
FHeight := 30;
FWidth := 30;
FTitle := '';
FStopped := false;
end;
Destructor TIntuitionWindowClass.Destroy;
begin
inherited;
end;
procedure TIntuitionWindowClass.Open;
var
aTitle : PChar;
begin
if FTitle <> '' then aTitle := PChar(FTitle) else aTitle := nil;
FHandle := OpenWindowTags( nil,
[
AsTag(WA_Left) , FLeft,
AsTag(WA_Top) , FTop,
AsTag(WA_Width) , FWidth,
AsTag(WA_Height) , FHeight,
AsTag(WA_Title) , aTitle,
// Non use settable flags (for now)
AsTag(WA_Flags) , AsTag(WFLG_CLOSEGADGET or WFLG_DRAGBAR or WFLG_DEPTHGADGET or WFLG_ACTIVATE or WFLG_GIMMEZEROZERO or WFLG_NOCAREREFRESH or WFLG_RMBTRAP or WFLG_REPORTMOUSE),
AsTag(WA_IDCMP) , AsTag(IDCMP_CLOSEWINDOW or IDCMP_MOUSEMOVE or IDCMP_MOUSEBUTTONS),
TAG_END
]);
if not Assigned(FHandle) then Error('Unable to Open Window');
end;
procedure TIntuitionWindowClass.Close;
begin
if Assigned(FHandle)
then Intuition.CloseWindow(FHandle)
else Error('Unable to Close Window because the handle is invalid');
end;
procedure TIntuitionWindowClass.HandleMessages;
var
msg : PIntuiMessage;
msgrec : TIntuitionMessageRec;
begin
while not FStopped do
begin
WaitPort(FHandle^.UserPort);
while true do
begin
msg := PIntuiMessage(GetMsg(FHandle^.UserPort));
if not Assigned(msg) then break;
// WriteLn('ReplyMsg');
ReplyMsg(pMessage(msg));
// WriteLn('Dispatch');
MsgRec.MsgCode := msg^.IClass;
MsgRec.IMsg := msg;
Dispatch(msgrec);
end;
end;
end;
(*
http://www.freepascal.org/docs-html/rtl/system/tobject.defaulthandler.html
DefaultHandler is the default handler for messages. If a message has an
unknown message ID (i.e. does not appear in the table with integer message
handlers), then it will be passed to DefaultHandler by the Dispatch method.
*)
(*
http://www.freepascal.org/docs-html/rtl/system/tobject.dispatch.html
Dispatch looks in the message handler table for a handler that handles
message. The message is identified by the first dword (cardinal) in the
message structure.
If no matching message handler is found, the message is passed to the
DefaultHandler method, which can be overridden by descendent classes to add
custom handling of messages.
*)
procedure TIntuitionWindowClass.DefaultHandler(var message);
begin
WriteLn('invoked default handler');
end;
procedure TIntuitionWindowClass.MsgCloseWindow(var msg: TIntuitionMessageRec);
var
DoClose: boolean = true;
begin
WriteLn('IDCMP_CLOSEWINDOW message received');
if Assigned(FOnCloseWindow) then FOnCloseWindow(DoClose);
FStopped := DoClose;
end;
procedure TIntuitionWindowClass.MsgMouseMove(var msg: TIntuitionMessageRec);
begin
WriteLn('IDCMP_MOUSEMOVE message received');
if assigned(FOnMouseMove) then FOnMouseMove(msg.IMsg);
end;
procedure TIntuitionWindowClass.MsgMouseButtons(var msg: TIntuitionMessageRec);
begin
WriteLn('IDCMP_MOUSEBUTTONS message received');
if Assigned(FOnMouseButtons) then FOnMouseButtons(msg.Imsg);
end;
end.
Looks difficult perhaps but, it actually isn't.
First we needed to add a new structure TIntuitionMessageRec that follows the Free Pascal Dispatch message, and at the same time can hold our intuition message information.
Then we've defined 3 new event procedures that act as type-casts for the events. The events FOnCloseWindow, FOnMouseMove and FOnMouseButtons are added to our private variables.
We override the DefaultHandler that is standard part of TObject so that we can give some feedback to the suer in case none of our message is intercepted correctly (and the default handler is invoked)
Finally we adjust our HandleMessages method to call the TObject dispatcher.
It might be a surprise, but there is nothing changed inside our main program. For the sake of completeness we post the code.
{$MODE OBJFPC}{$H+}
uses
IntWinClass, Exec, AGraphics, Intuition, InputEvent;
//*-------------------------------------------------------------------------*/
//* Main routine */
//*-------------------------------------------------------------------------*/
function main: integer;
var
Window1 : TIntuitionWindowClass;
begin
Window1 := TIntuitionWindowClass.Create;
Window1.Left := 10;
Window1.Top := 20;
Window1.Height := 200;
Window1.Width := 320;
Window1.Title := 'This is window 1';
Window1.Open;
Window1.HandleMessages;
Window1.Close;
Window1.Free;
result := (0);
end;
begin
ExitCode := Main;
end.
Implement message handlers
In our last step we would like to call the event handlers instead of our class actually performing actions, so we start doing so (yes we shuffle the code around again):
unit IntWinClass;
{$MODE OBJFPC}{$H+}
interface
uses
Intuition;
type
TIntuitionMessageRec = record
MsgCode : DWord;
IMsg : PIntuiMessage;
end;
type
TOnCloseWindowProc = procedure(var DoClose: boolean);
TOnMouseMoveProc = procedure(const IMsg: PIntuiMessage);
TOnMouseButtonsProc = procedure(const IMsg: PIntuiMessage);
TIntuitionWindowClass = class
private
FHandle : PWindow;
FLeft : LongInt;
FTop : LongInt;
FWidth : LongInt;
FHeight : LongInt;
FTitle : AnsiString;
FStopped : boolean;
FOnCloseWindow : TOnCloseWindowProc;
FOnMouseMove : TOnMouseMoveProc;
FOnMouseButtons : TOnMouseButtonsProc;
protected
procedure MsgCloseWindow(var msg: TIntuitionMessageRec); Message IDCMP_CLOSEWINDOW;
procedure MsgMouseMove(var msg: TIntuitionMessageRec); Message IDCMP_MOUSEMOVE;
procedure MsgMouseButtons(var msg: TIntuitionMessageRec); Message IDCMP_MOUSEBUTTONS;
public // creator/destructor
constructor Create;
destructor Destroy; override;
public // methods
procedure Open;
procedure Close;
procedure HandleMessages;
procedure DefaultHandler(var message); override;
public // properties
property Left : LongInt read FLeft write FLeft;
property Top : LongInt read FTop write FTop;
property Width : LongInt read FWidth write FWidth;
property Height : LongInt read FHeight write FHeight;
property Title : String read FTitle write FTitle;
property Handle : PWindow read FHandle;
public // events
property OnCloseWindow : TOnCloseWindowProc read FOnCloseWindow write FOnCloseWindow;
property OnMouseMove : TOnMouseMoveProc read FOnMouseMove write FOnMouseMove;
property OnMouseButtons : TOnMouseButtonsProc read FOnMouseButtons write FOnMouseButtons;
end;
implementation
uses
SysUtils, Exec, AGraphics, InputEvent;
function AsTag(tag: LongWord): LongInt; inline;
begin
Result := LongInt(tag);
end;
procedure error(Const msg : string);
begin
raise exception.create(Msg) at
get_caller_addr(get_frame),
get_caller_frame(get_frame);
end;
Constructor TIntuitionWindowClass.Create;
begin
Inherited;
FHandle := nil;
FLeft := 10;
FTop := 10;
FHeight := 30;
FWidth := 30;
FTitle := '';
FStopped := false;
end;
Destructor TIntuitionWindowClass.Destroy;
begin
inherited;
end;
procedure TIntuitionWindowClass.Open;
var
aTitle : PChar;
begin
if FTitle <> '' then aTitle := PChar(FTitle) else aTitle := nil;
FHandle := OpenWindowTags( nil,
[
AsTag(WA_Left) , FLeft,
AsTag(WA_Top) , FTop,
AsTag(WA_Width) , FWidth,
AsTag(WA_Height) , FHeight,
AsTag(WA_Title) , aTitle,
// Non use settable flags (for now)
AsTag(WA_Flags) , AsTag(WFLG_CLOSEGADGET or WFLG_DRAGBAR or WFLG_DEPTHGADGET or WFLG_ACTIVATE or WFLG_GIMMEZEROZERO or WFLG_NOCAREREFRESH or WFLG_RMBTRAP or WFLG_REPORTMOUSE),
AsTag(WA_IDCMP) , AsTag(IDCMP_CLOSEWINDOW or IDCMP_MOUSEMOVE or IDCMP_MOUSEBUTTONS),
TAG_END
]);
if not Assigned(FHandle) then Error('Unable to Open Window');
end;
procedure TIntuitionWindowClass.Close;
begin
if Assigned(FHandle)
then Intuition.CloseWindow(FHandle)
else Error('Unable to Close Window because the handle is invalid');
end;
procedure TIntuitionWindowClass.HandleMessages;
var
msg : PIntuiMessage;
msgrec : TIntuitionMessageRec;
begin
while not FStopped do
begin
WaitPort(FHandle^.UserPort);
while true do
begin
msg := PIntuiMessage(GetMsg(FHandle^.UserPort));
if not Assigned(msg) then break;
// WriteLn('ReplyMsg');
ReplyMsg(pMessage(msg));
// WriteLn('Dispatch');
MsgRec.MsgCode := msg^.IClass;
MsgRec.IMsg := msg;
Dispatch(msgrec);
end;
end;
end;
(*
http://www.freepascal.org/docs-html/rtl/system/tobject.defaulthandler.html
DefaultHandler is the default handler for messages. If a message has an
unknown message ID (i.e. does not appear in the table with integer message
handlers), then it will be passed to DefaultHandler by the Dispatch method.
*)
(*
http://www.freepascal.org/docs-html/rtl/system/tobject.dispatch.html
Dispatch looks in the message handler table for a handler that handles
message. The message is identified by the first dword (cardinal) in the
message structure.
If no matching message handler is found, the message is passed to the
DefaultHandler method, which can be overridden by descendent classes to add
custom handling of messages.
*)
procedure TIntuitionWindowClass.DefaultHandler(var message);
begin
WriteLn('invoked default handler');
end;
procedure TIntuitionWindowClass.MsgCloseWindow(var msg: TIntuitionMessageRec);
var
DoClose: boolean = true;
begin
WriteLn('IDCMP_CLOSEWINDOW message received');
if Assigned(FOnCloseWindow) then FOnCloseWindow(DoClose);
FStopped := DoClose;
end;
procedure TIntuitionWindowClass.MsgMouseMove(var msg: TIntuitionMessageRec);
begin
WriteLn('IDCMP_MOUSEMOVE message received');
if assigned(FOnMouseMove) then FOnMouseMove(msg.IMsg);
end;
procedure TIntuitionWindowClass.MsgMouseButtons(var msg: TIntuitionMessageRec);
begin
WriteLn('IDCMP_MOUSEBUTTONS message received');
if Assigned(FOnMouseButtons) then FOnMouseButtons(msg.Imsg);
end;
Now that the event handling is actually implemented we can make use of it in our main program.
program ClassWindow;
{$MODE OBJFPC}{$H+}
uses
IntWinClass, Exec, AGraphics, Intuition, InputEvent;
procedure print_text(rp: PRastPort; x: LongInt; y: LongInt; txt: PChar);
begin
GfxMove(rp, x, y);
SetABPenDrMd(rp, 1, 0, JAM2);
GfxText(rp, txt, strlen(txt));
ClearEOL(rp);
end;
//*-------------------------------------------------------------------------*/
//* Window1 events
//*-------------------------------------------------------------------------*/
procedure DoMouseMove(const IMsg: PIntuiMessage);
var
buffer : String[80];
begin
WriteStr(buffer, 'Mouseposition: x=', IMsg^.MouseX, ' y=', IMsg^.MouseY, #0);
print_text(IMsg^.IDCMPWindow^.RPort, 10, 30, @buffer[1]);
end;
procedure DoMouseButtons(const IMsg: PIntuiMessage);
begin
case IMsg^.Code of
IECODE_LBUTTON : print_text(IMsg^.IDCMPWindow^.RPort, 10, 60, 'Left mousebutton pressed');
IECODE_LBUTTON or IECODE_UP_PREFIX : print_text(IMsg^.IDCMPWindow^.RPort, 10, 60, 'Left mousebutton released');
IECODE_RBUTTON : print_text(IMsg^.IDCMPWindow^.RPort, 10, 90, 'Right mousebutton pressed');
IECODE_RBUTTON or IECODE_UP_PREFIX : print_text(IMsg^.IDCMPWindow^.RPort, 10, 90, 'Right mousebutton released');
end;
end;
procedure DoCloseWindow(var DoClose: boolean);
begin
DoClose := True;
end;
//*-------------------------------------------------------------------------*/
//* Main routine */
//*-------------------------------------------------------------------------*/
function main: integer;
var
Window1 : TIntuitionWindowClass;
begin
Window1 := TIntuitionWindowClass.Create;
Window1.Left := 10;
Window1.Top := 20;
Window1.Height := 200;
Window1.Width := 320;
Window1.Title := 'This is window 1';
Window1.OnMouseMove := @DoMouseMove;
Window1.OnMouseButtons := @DoMouseButtons;
Window1.OnCloseWindow := @DoCloseWindow;
Window1.Open;
Window1.HandleMessages;
Window1.Close;
Window1.Free;
result := (0);
end;
begin
ExitCode := Main;
end.
Depending on which events are assigned our class is acting as desired. You can leave those events that you are not interested in or add new ones inside the class.
What's next ?
The above example is far from a full working windowclass. There are several issues with the current implementation:
- Properties such as Left and Height currently retrieve their values from private variables. This is plain wrong as the user can move the window around and resize it. None of the current properties are actually containing real live values. Several approaches can be taken to improve this situation, f.e. by retrieving the actual values or for example by also implementing and reacting on RESIZEWINDOW and MOVEWINDOW messages.
- The current implementation only takes care of a single window. Calling HandleMessages would only work for this one window (and further message handing would be stalled). In order to add support for multiple windows a 'global' message-loop would have to implemented using a single messageport (that is used for all windows). Note that in that case the creation of the window can not have it's IDCMP_xxx flags set on creation, but needs to be done with function ModifyIDCMP()