[Webinar] Streamline your web hosting managementRegister Today

x
?
Solved

Restrict drawing on a canvas into a rectangle?

Posted on 2000-02-22
4
Medium Priority
?
401 Views
Last Modified: 2010-04-04
I need to specify a rectangle on a canvas where drawing is enabled, and outside it is forbidden. For example, in Rect(25, 25, 200, 200) drawing is enabled, and anything drawn outside it is not displayed.

Please note, that the canvas in question is the canvas of a printer.

How can I do that?
Thank you for your help.
Levente
0
Comment
Question by:Levente
  • 2
  • 2
4 Comments
 
LVL 17

Expert Comment

by:inthe
ID: 2548194
Hi,
here an example of reading .lnk files:

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls,shlobj,activex,comobj,commctrl,menus;

type
  TForm1 = class(TForm)
    Button1: TButton;
    OpenDialog1: TOpenDialog;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }

  public
    { Public declarations }
  end;

var
  Form1: TForm1;
   NeedToUninitialize : boolean = false;
implementation

{$R *.DFM}

function LoadShellLink(shellLinkFile: string;
                       var description, linkedObj, params: string;
                       var pidl: PItemIDList; var findData: TWin32FindData;
                       var iconPath: string; var iconIndex: integer;
                       var workingDir, hotKey: string;
                       var showCmd: integer) : boolean;
var sl  : IShellLink;
    w1  : word;
    s1  : string;
    wfd : TWin32FindData;
    i1  : integer;
begin
  NeedToUninitialize:=NeedToUninitialize or succeeded(CoInitialize(nil));
  sl:=CreateComObject(CLSID_ShellLink) as IShellLink;
  result:=(sl as IPersistFile).Load(PWideChar(wideString(ShellLinkFile)),0)=S_OK;
  if not result then exit;
  SetLength(description,MAX_PATH+1);
  if sl.GetDescription(PChar(description),MAX_PATH)=NOERROR then description:=string(PChar(description))
  else                                                           description:='';
  SetLength(s1,MAX_PATH+1);
  if sl.GetPath(PChar(s1),MAX_PATH,wfd,0)=NOERROR then begin
    linkedObj:=string(PChar(s1));
    findData :=wfd;
  end else begin
    linkedObj:='';
    ZeroMemory(@findData,sizeOf(TWin32FindData));
  end;
  SetLength(params,MAX_PATH+1);
  if sl.GetArguments(PChar(params),MAX_PATH)=NOERROR then params:=string(PChar(params))
  else                                                    params:='';
  if sl.GetIDList(pidl)<>NOERROR then pidl:=nil;
  SetLength(s1,MAX_PATH+1);
  if sl.GetIconLocation(pchar(s1),MAX_PATH,i1)=NOERROR then begin
    iconPath :=string(pchar(s1));
    iconIndex:=i1;
  end else begin
    iconPath :='';
    iconIndex:=-1;
  end;
  SetLength(workingDir,MAX_PATH+1);
  if sl.GetWorkingDirectory(PChar(workingDir),MAX_PATH)=NOERROR then workingDir:=string(PChar(workingDir))
  else                                                               workingDir:='';
  sl.GetHotKey(w1);
  if w1 and (HOTKEYF_ALT     shl 8)<>0 then w1:=(w1 and (not (HOTKEYF_ALT     shl 8))) or scAlt;
  if w1 and (HOTKEYF_CONTROL shl 8)<>0 then w1:=(w1 and (not (HOTKEYF_CONTROL shl 8))) or scCtrl;
  if w1 and (HOTKEYF_SHIFT   shl 8)<>0 then w1:=(w1 and (not (HOTKEYF_SHIFT   shl 8))) or scShift;
  hotKey:=ShortCutToText(w1);
  if sl.GetShowCmd(showCmd)<>NOERROR then showCmd:=-1;
end;

procedure FreePidl(var pidl: PItemIDList);
var malloc : IMalloc;
begin
  if (pidl<>nil) and (SHGetMalloc(malloc)=NOERROR) then begin
    malloc.Free(pidl);
    pidl:=nil;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  pi:PItemIDList;
  s1,Desc,s2:String;
  icon,workdir,htkey:string;
  Data: TWin32FindData;
  i,ii : integer;
begin
  opendialog1.execute;
  loadshelllink(opendialog1.filename,desc,s1,s2,pi,Data,icon,i,workdir,htkey,ii);
  ShowMessage('File ShortCut : '+opendialog1.filename+#13#10+'File TruePath : '+s1+#13#10+'Working Dir : '+workdir+#13#10
              +'HotKey : '+htkey+#13#10+'Show Command : '+inttostr(ii));
 FreePidl(pi);
end;


initialization
finalization
  if NeedToUninitialize then CoUninitialize;

end.


Regards Barry
0
 
LVL 17

Expert Comment

by:inthe
ID: 2548208
opps silly me ,im sorry i pasted in wrong question :-)
0
 
LVL 8

Accepted Solution

by:
ZifNab earned 600 total points
ID: 2548286
Hi Levente,

This should do the trick (with TImage as example, but should be same for printer canvas)

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, ExtCtrls;

type
  TForm1 = class(TForm)
    Image1: TImage;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.Button1Click(Sender: TObject);
  Var Region, OldRegion : HRgn;
      DC        : HDC;

begin
  DC:=Image1.Canvas.Handle;
  Region:=CreateRectRgn(10,10,50,50);
  GetClipRgn(DC,OldRegion);
  SelectClipRgn(DC,Region);
  DeleteObject(Region);
  with Image1 do
  begin
    Canvas.Pen.Color := Random(65535);
    Canvas.Pen.Style := psSolid;
    Canvas.Rectangle(5, 5, 20,20);
  end;
end;

end.

Regards, Zif.

0
 
LVL 8

Expert Comment

by:ZifNab
ID: 2548303
For TPrinter :

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, ExtCtrls;

type
  TForm1 = class(TForm)
    Image1: TImage;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation
uses printers;
{$R *.DFM}

procedure TForm1.Button1Click(Sender: TObject);
  Var Region, OldRegion : HRgn;
      DC        : HDC;

begin
  Printer.BeginDoc;
  DC:=Printer.Canvas.Handle;
  Region:=CreateRectRgn(10,10,50,50);
  GetClipRgn(DC,OldRegion);
  SelectClipRgn(DC,Region);
  DeleteObject(Region);
  with Printer do
  begin
    Canvas.Pen.Color := Random(65535);
    Canvas.Pen.Style := psSolid;
    Canvas.Rectangle(5, 5, 20,20);
  end;
  Printer.EndDoc;
  SelectClipRgn(DC,OldRegion);
end;

end.

What you see printed is just the right-bottom corner of the rectangle. The rest is clipped.


Regards, Zif.
0

Featured Post

Keep up with what's happening at Experts Exchange!

Sign up to receive Decoded, a new monthly digest with product updates, feature release info, continuing education opportunities, and more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Hello everybody This Article will show you how to validate number with TEdit control, What's the TEdit control? TEdit is a standard Windows edit control on a form, it allows to user to write, read and copy/paste single line of text. Usua…
Introduction Raise your hands if you were as upset with FireMonkey as I was when I discovered that there was no TListview.  I use TListView in almost all of my applications I've written, and I was not going to compromise by resorting to TStringGrid…
Is your OST file inaccessible, Need to transfer OST file from one computer to another? Want to convert OST file to PST? If the answer to any of the above question is yes, then look no further. With the help of Stellar OST to PST Converter, you can e…
Free Data Recovery software is an advanced solution from Kernel Tools to recover data and files such as documents, emails, database, media and pictures, etc. It supports recovery from physical & logical drive after a hard disk crash, accidental/inte…
Suggested Courses
Course of the Month10 days, 9 hours left to enroll

612 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question