Chip 1999 March/Chip_1999-03_cd.bin/zkuste/delphi/D12/ALREP.ZIP/alprev.pas

Pascal/Delphi Source File | 1998-08-13 | 5KB | 202 lines

unit alprev;

interface

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

type
  tAlPreview = class(TScrollBox)     // tScrollingWinControl ???
  private
    { Private-Deklarationen }
    fPage   : integer;
    fZoom   : integer;
    pbxPage : tPaintbox;
    FTitle  : string;
    fBusy   : boolean;
    procedure SetPageNumber(value:integer);
    function  GetPageCount:integer;
    procedure SetZoom (value:integer);
    procedure UpdatePage(Sender:tObject);
  protected
    { Protected-Deklarationen }
  public
    FPages  : tPages;
    { Public-Deklarationen }
    constructor Create (aOwner:tComponent); override;
    destructor Destroy; override;
    procedure  FirstPage;
    procedure  LastPage;
    procedure  NextPage;
    procedure  PrevPage;
    procedure  Print (pfrom,pto:integer);
    property PageNumber:integer read fPage write SetPageNumber;
    property Zoom:integer read fZoom write SetZoom default 100;
    property PageCount:integer read GetPageCount;
    property Busy:boolean read FBusy;
//    property Pages:tPages read FPages write FPages;
  published
    { Published-Deklarationen }
    property Title:string read FTitle write FTitle;
  end;

procedure Register;

implementation
uses
  Printers;

constructor tAlPreview.Create(aOwner:tComponent);
begin
  inherited Create (aOwner);

  fPage  := 1;
  fZoom := 100;
  fBusy := false;
  if NOT (csDesigning in ComponentState) then
   begin
     pbxPage := tPaintBox.Create(Self);
     pbxPage.Parent := Self;

     pbxPage.Left        := 15;
     pbxPage.Top         := 15;
     pbxPage.Width       := 823;   // Din A4 screen width
     pbxPage.Height      := 1164; // Din A4 screen height
     pbxPage.ParentColor := false;
     pbxPage.Color       := clWindow;

     FPages := tPages.Create;
     pbxPage.OnPaint := UpdatePage;
   end;
end;

destructor tAlPreview.Destroy;
begin
  if not (csDesigning in ComponentState) then
   begin
     fPages.Clear;
     fPages.Free;
     pbxPage.Free;
   end;
  inherited destroy;
end;

procedure tAlPreview.UpdatePage(Sender:tObject);
begin
  pbxPage.Width := Round(AlPrinter.PageWidth*fZoom/100.0);
  pbxPage.Height := Round(AlPrinter.PageHeight*fZoom/100.0);
  VertScrollBar.Range := pbxPage.Height+30;
  HorzScrollBar.Range := pbxPage.Width+30;
  pbxPage.Canvas.Brush.Color := clWindow;
  pbxPage.Canvas.FillRect (pbxPage.ClientRect);
  if (fPage>0) and (fPage<=PageCount) then
     pbxPage.Canvas.StretchDraw(pbxPage.ClientRect,FPages[fPage-1]);
end;

procedure tAlPreview.SetPageNumber(value:integer);
begin
  if (value>0) and (value<=AlPrinter.PageCount) then
   begin
     fPage := value;
     UpdatePage (Self);
   end;
end;

function tAlPreview.GetPageCount:integer;
begin
  result := FPages.Count;
end;

procedure tAlPreview.SetZoom(value:integer);
begin
  if value<>fZoom then
   if (value>=25) and (value<=200) then
    begin
      fZoom := value;
      UpdatePage (Self);
    end;
end;

procedure tAlPreview.FirstPage;
begin
  SetPageNumber (1);
end;

procedure tAlPreview.LastPage;
begin
  if {AlPrinter.}PageCount>0 then
     SetPageNumber ({AlPrinter.}PageCount);
end;

procedure tAlPreview.NextPage;
begin
  if fPage<{AlPrinter.}PageCount then
   begin
     inc (fPage);
     UpdatePage (Self);
   end;
end;

procedure tAlPreview.PrevPage;
begin
  if fPage>1 then
   begin
     dec(fPage);
     UpdatePage (Self);
   end;
end;

procedure tAlPreview.Print (pFrom,pTo:integer);
var
   i : Integer;
   s : String;
begin
  FBusy := true;
  if PageCount > 0 then
   begin
     Printer.Title := Title;
     if not Printer.Printing then
        Printer.BeginDoc;
     i := pFrom;
//     if Assigned(Print_Preview) then
//        s := Print_Preview.Panel2.Caption;
     try
//       if Assigned(Print_Preview) then
//        begin
//          Print_Preview.Panel2.Caption :=
//             Format('Printing page %d of %d',[1, PageCount]);
//          Print_Preview.Panel2.repaint;
//        end;
       Printer.Canvas.StretchDraw( Rect(0,0,Printer.PageWidth,
                                            Printer.PageHeight),
                                   FPages[i-1]);
       for i := pFrom+1 to pTo do
        begin
//          if Assigned(Print_Preview) then
//           begin
//             Print_Preview.Panel2.Caption :=
//                Format('Printing page %d of %d',[i, PageCount]);
//             Print_Preview.Panel2.repaint;
//           end;
          Printer.NewPage;
          Printer.Canvas.StretchDraw( Rect(0,0,Printer.PageWidth,
                                               Printer.PageHeight),
                                      FPages[i-1]);
        end;
     finally
        Printer.EndDoc;
//     if Assigned(Print_Preview) then
//        Print_Preview.Panel2.Caption := s;
     end; // try ... finally
   end; // if PageCount>0
  FBusy := false;
end; // procedure tAlPreview.Print

procedure Register;
begin
  RegisterComponents('AlRep', [tAlPreview]);
end;

end.