nvas:TCanvas;Left,Top,Width,Height:integer;PanelType:integer);
var
Right,Bottom:integer;
LeftTopColor,RightBottomColor:TColor;
begin
//凸起的panel
if PanelType=RaisedPanel then
begin
LeftTopColor:=clwhite;
RightBottomColor:=clgray;
end
else //凹下去的panel
begin
LeftTopColor:=clgray;
RightBottomColor:=clwhite;
end;
Right:=Left+width;
Bottom:=Top+Height;
Canvas.Pen.Width:=1;
Canvas.Pen.Color:=LeftTopColor;
Canvas.MoveTo(Right,Top);
Canvas.lineTo(Left,Top);
Canvas.LineTo(Left,bottom);
Canvas.Pen.Color:=RightBottomColor;
Canvas.lineTo(Right,Bottom);
Canvas.lineTo(Right,Top);
end;
8.接下来我们在ListView1的OnSelectItem事件里添加代码：
procedure TForm1.ListView1SelectItem(Sender: TObject; Item: TListItem;
Selected: Boolean);
begin
//当ShellTreeView1目录改变时 会激发此事件，
if listview1.SelCount=0 then exit;
//当窗体释放时也会激发此事件
//ImageFileList.GetFileCount=0 后再 ImageFileList.SetIndex(item.Index);
//会引起异常
if ImageFileList.GetFileCount=0 then exit;
ImageFileList.SetIndex(item.Index);
ShowPreImageFit(ImageFileList.GetCurFullFileName);
end;
9.其中过程ShowImageFit的代码比较罗嗦，如下所示：
//image1在Panel1中居中显示图片文件ImageFileName
procedure TForm1.ShowPreImageFit(const ImageFileName: string);
begin
Image1.Visible:=false;
if IsJpgFile(ImageFileName) then
begin
JpgToBmp(ImageFileName,PreViewJpg,PreViewBmp);
Image1.Picture.Bitmap:=PreViewBmp;
end
else
Image1.Picture.LoadFromFile(ImageFileName);
if (Image1.Picture.Bitmap.Height<=Panel1.Height) and (image1.Picture.Bitmap.Width<=Panel1.Width) then
begin
Image1.AutoSize:=true;
Image1.Stretch:=true;
Image1.Left:=(Panel1.Width-image1.Width) div 2;
Image1.Top:=(Panel1.Height-image1.Height) div 2;
end
else if Panel1.Height>=Panel1.Width then
begin
Image1.AutoSize:=false;
Image1.Stretch:=true;
if image1.Picture.Bitmap.Height>=image1.Picture.Bitmap.Width then
begin
image1.Height:=Panel1.Width;
Image1.Width:=Image1.Height*Image1.Picture.Bitmap.Width div Image1.Picture.Bitmap.Height;
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