分享一个浏览图片的类。GDI+的一个应用

kuangning 2012-03-28 11:02:01

前几天有人做了个360的界面他说自己的没立体感。我叫他用GDI+画一个半透明的边框他好像没理会。
故今天心血来潮写了个浏览文件夹图片的类。给大家分享
借助gdi+库（该库的delphi单元在本站有下载，“阿发伯”提供）和Tpaintbox
下面是代码



unit fuImageListView;



interface



uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, StdCtrls, ExtCtrls,Gdiplus;



const

   imgRectWidth = 110;

   imgRectHeight = 150;

   imgWidth = 60;

   imgHeight =90;

   ImgOffSetX =  (imgRectWidth -  imgWidth) div 2;

   ImgOffsetY =   6;



type

  PImageItem=^TImageItem;

  TImageItem=record

    fileName:string;

    Rect:TRect;

    ImgRect:TRect;

    RGN:HRGN;

    Name:string;

  end;



  TImageListView=class

  private

    FPaintBox: TPaintBox;

    FLookDir: string;

    FList : TList;

    FFocusItem:PImageItem;

    FSelectItem:PImageItem;

    procedure SetLookDir(const Value: string);

    function getCount: Integer;

    function GetItems(index: Integer): PImageItem;

    procedure SetFocusItem(const Value: PImageItem);

    procedure SetSelectItem(const Value: PImageItem);

  protected

    procedure DrawImageList;

    procedure DrawImage(const G:TGpGraphics;const P:PImageItem);

    procedure PaintBoxPaint(Sender: TObject);

    procedure PaintBoxMouseMove(Sender: TObject; Shift: TShiftState; X,

      Y: Integer);

    procedure PaintBoxMouseDown(Sender: TObject; Button: TMouseButton;

  Shift: TShiftState; X, Y: Integer);

    function GetFocusItem(const X,Y : Integer):PImageItem;



  public

    property PaintBox : TPaintBox read FPaintBox;

    constructor Create(const aPaintBox:TPaintBox);

    destructor Destroy; override;

    property LookDir : string read FLookDir write SetLookDir;

    property Count : Integer read getCount;

    procedure Delete(const Index:Integer);

    procedure Clear;

    property  Items[index:Integer]: PImageItem read GetItems;

    property  FocusItem:PImageItem read FFocusItem write SetFocusItem;

    property  SelectItem:PImageItem read FSelectItem write SetSelectItem;

  end;







implementation



uses

   Math;



{ TImageListView }



procedure FillRectangle(const GDIgraphics:TGPGraphics;const X1,Y1:Integer;const X2:Integer;const Y2:Integer;

     const Color:TColor;const penWidth:Integer ;  const FillMode:Boolean;

     const AlphaBlendValue:Byte );

var

  SB: TGPSolidBrush;

  P:TGpPen;

  gdiColor:Cardinal;

  left,right,top, bottom:Integer;

begin

   left  := min(X1,X2);

   right := Max(x1,X2);

   top := min (Y1,Y2);

   bottom := Max(Y1,Y2) ;

  gdiColor := ARGBFromTColor(Color);

  gdiColor := (gdiColor and $FFFFFF) or (AlphaBlendValue shl 24);

  try

          GDIgraphics.SmoothingMode:= smAntiAlias;

          if FillMode then

          begin

             SB := TGPSolidBrush.Create(gdiColor);

             try

                  GDIgraphics.FillRectangle(sb,left,top,right-left,bottom-top);

             except



             end;

             SB.Free;

          end else

          begin

            P := TGpPen.Create(gdiColor,penWidth);

            try

                  GDIgraphics.DrawRectangle(P,left,top,right-left,bottom-top);

            except



            end;



            p.Free;

          end;

  except



  end;



end;



procedure TImageListView.Clear;

begin

      while Count>0 do

      Delete(0);

end;



constructor TImageListView.Create(const aPaintBox: TPaintBox);

begin

   FPaintBox := aPaintBox;

   aPaintBox.OnPaint := PaintBoxPaint;

   aPaintBox.OnMouseMove := PaintBoxMouseMove;

   aPaintBox.OnMouseDown := PaintBoxMouseDown;

   FList := TList.Create;

   if FPaintBox.Parent <> nil then

   FPaintBox.Parent.DoubleBuffered := True;

end;



procedure TImageListView.Delete(const Index: Integer);

var

  P:PImageItem;

begin

   P := Flist.Items[index];

   DeleteObject(p.RGN);

   Dispose(P);

   Flist.Delete(index);

end;



destructor TImageListView.Destroy;

begin

  Clear;

  Flist.Free;

  inherited;

end;



procedure TImageListView.DrawImage(const G: TGpGraphics; const P: PImageItem);

var

  image : TGpImage;

  rt: TGPRectF;

  aZoom:Real;

  strFormat: TGpStringFormat;

  font: TGpFont;

  rect1 :TGpRectF;

begin

    image := TGpImage.Create(p.fileName);

    if image.Width * image.Height >0 then

    begin

          g.InterpolationMode := imHighQualityBicubic;



          aZoom :=  Min( imgWidth/image.Width,imgHeight/image.Height);

          rt.Width :=image.Width*aZoom;

          rt.Height :=image.Height*azoom;

          rt.X := (imgWidth-image.Width*aZoom) / 2 + p.ImgRect.Left;

          rt.Y := (imgHeight-image.Height*aZoom) / 2 +p.ImgRect.top;

          g.DrawImage(image,rt,  0, 0, image.Width, image.Height, utPixel);

          try





                  font := TGpFont.Create('arial', 10, []);

                  strFormat := TGpStringFormat.Create([]);

                  strFormat.Alignment := saCenter;

                 // strFormat.

                 

                //  g.DrawString(p.Name, font, Brushs[$99000000],p.Rect.Left+imgRectWidth /2, p.Rect.Bottom-20, strFormat);

                rect1.X :=p.Rect.Left;

                rect1.Y :=  p.Rect.Bottom-55;

                rect1.Width :=imgRectWidth-4;

                rect1.Height := 55;



                    g.DrawString(p.Name,   font,  Brushs[$F0000000],    rect1,  strFormat)



          except



          end;

          if Assigned(font) then



          font.Free;

          if Assigned(strFormat) then



          strFormat.Free;



          if FocusItem= P then

           begin

              FillRectangle(G, p.Rect.Left+2,p.Rect.Top+2,

               p.Rect.Right-2,p.Rect.Bottom-2,RGB(209,229,252),1,True,20); //画半透明填充框

               FillRectangle(G, p.Rect.Left+2,p.Rect.Top+2,

                p.Rect.Right-2,p.Rect.Bottom-2,RGB(209,229,252),1,False,$FF);  //画不透明外框

           end;

           if FSelectItem=p then

           begin

             FillRectangle(G, p.Rect.Left+2,p.Rect.Top+2,

               p.Rect.Right-2,p.Rect.Bottom-2,RGB(32,97,193),1,True,20); //画半透明填充框

              FillRectangle(G, p.Rect.Left+2,p.Rect.Top+2,

                p.Rect.Right-2,p.Rect.Bottom-2,RGB(32,97,193),1,False,120); //画半透明外框

           end;

    end;

    image.Free;



end;



procedure TImageListView.DrawImageList;

var

  RowCount,ColCount:Integer;

  P:PImageItem;

  K:Integer;

  I , J :Integer;



begin

   if Assigned(FPaintBox) then

   begin

      ColCount := (FPaintBox.Width -25) div imgRectWidth;

      if ColCount > 0 then

      begin

         RowCount :=  Flist.Count div ColCount;

         if  Flist.Count mod ColCount<>0 then

         Inc(RowCount);

         FPaintBox.Height := RowCount* imgRectHeight;



         K := 0 ;

         for I:= 0 to RowCount - 1 do

            for J := 0 to ColCount - 1 do

            begin

                P := Flist.Items[K];

                P^.Rect.Left := J*imgRectWidth;

                P^.Rect.Top := I*imgRectHeight;

                p^.Rect.Right := P^.Rect.Left + imgRectWidth;

                p^.Rect.Bottom := P^.Rect.Top +  imgRectHeight;

                P^.ImgRect := Rect(P^.Rect.Left+ImgOffSetX,P^.Rect.Top + ImgOffsetY,

                                        P^.Rect.Right-ImgOffSetX,P^.Rect.Bottom - ImgOffsetY) ;

                P^.RGN := CreateRectRgn(P^.ImgRect.Left,P^.ImgRect.Top,P^.ImgRect.Right,P^.ImgRect.Bottom );

                Inc(K);

                if K>=Flist.Count  then

                   Break;

            end;



      end;

   end;

end;



function TImageListView.getCount: Integer;

begin

   Result := FList.Count;

end;



function TImageListView.GetFocusItem(const X, Y: Integer): PImageItem;

var

  I:Integer;

begin

  Result := nil;

  for I := 0 to FList.Count - 1 do

  begin

    if ptinregion(Items[i].RGN,X,Y) then

    begin

      Result :=Items[i];

      Break;

    end;

    

  end;



end;



function TImageListView.GetItems(index: Integer): PImageItem;

begin

    Result := FList.Items[index];

end;







procedure TImageListView.PaintBoxMouseDown(Sender: TObject;

  Button: TMouseButton; Shift: TShiftState; X, Y: Integer);

begin

 SelectItem:=  GetFocusItem(x,y);

end;



procedure TImageListView.PaintBoxMouseMove(Sender: TObject; Shift: TShiftState;

  X, Y: Integer);



begin

  FocusItem:=  GetFocusItem(x,y);



  

end;





procedure TImageListView.PaintBoxPaint(Sender: TObject);

var

    G: TGpGraphics;

    I:Integer;

begin

           G := TGpGraphics.Create(FPaintBox.Canvas.Handle);

           for I := 0 to FList.Count - 1 do

              DrawImage(G,FList.Items[i]);





           G.Free;

end;



procedure TImageListView.SetFocusItem(const Value: PImageItem);

begin

  if FFocusItem <> Value then

  begin

    FFocusItem := Value;

    FPaintBox.Repaint;

  end;

  



end;



procedure TImageListView.SetLookDir(const Value: string);

var

    SearchRec   :   TSearchRec;

    Attr   :   integer;

    Found   :   integer;

    ExtFileName:string;

    temstr:string;

    P:PImageItem;

begin

    FLookDir := Value;

    Clear;

    temstr:=Value+ '*.*';

    Attr   :=   faAnyFile;

    Found   :=   FindFirst(temstr,   Attr,   SearchRec);

    while   Found   =   0   do 

    begin 

        ExtFileName:=LowerCase(ExtractFileExt(SearchRec.Name)); 

        if   (ExtFileName= '.bmp')   or   (ExtFileName= '.jpg')   or   ((ExtFileName= '.jpeg'))   then

        begin

          New(P);

          P^.fileName :=  FLookDir+SearchRec.Name;

          P^.Name := SearchRec.Name;

          FList.Add(P)

        end;

        Found   :=   FindNext(SearchRec);

    end; 

    FindClose(SearchRec);

    DrawImageList;

end;



procedure TImageListView.SetSelectItem(const Value: PImageItem);

begin

  if FSelectItem <> Value then

  begin

    FSelectItem := Value;

    FPaintBox.Repaint;

  end;



end;



end.