[原创]Delphi XE Android/IOS 实现图片放大缩小的两种方法

{该文首发于博客园 滔Roy，无须授权即可转发，请自觉保留头部申明}

Delphi XE Android/IOS 实现图片放大缩小的两种方法

1、TImage

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

var   LObj: IControl;   LImage: TImage;   LImageCenter: TPointF; begin   if EventInfo.GestureID = igiZoom then   begin     LObj := Self.ObjectAtPoint(ClientToScreen(EventInfo.Location));     if LObj is TImage then     begin       if (not(TInteractiveGestureFlag.gfBegin in EventInfo.Flags)) and         (not(TInteractiveGestureFlag.gfEnd in EventInfo.Flags)) then       begin         { zoom the image }         LImage := TImage(LObj.GetObject);         LImageCenter := LImage.Position.Point + PointF(LImage.Width / 2,           LImage.Height / 2);         LImage.Width := LImage.Width + (EventInfo.Distance - FLastDistance);         LImage.Height := LImage.Height + (EventInfo.Distance - FLastDistance);         LImage.Position.X := LImageCenter.X - LImage.Width / 2;         LImage.Position.Y := LImageCenter.Y - LImage.Height / 2;       end;       FLastDistance := EventInfo.Distance;     end;   end;

 

2、TImageViewer

?

1 2 3 4 5 6 7 8 9 10 11 12 13

procedure TForm1.ImageViewer1Gesture(Sender: TObject;   const EventInfo: TGestureEventInfo; var Handled: Boolean); begin   case EventInfo.GestureID of     igiZoom:     begin       if (EventInfo.Distance - fDistance)/2 > 0 then ImageViewer1.BitmapScale:=ImageViewer1.BitmapScale + 0.01  else       if (EventInfo.Distance - fDistance)/2 < 0 then ImageViewer1.BitmapScale:=ImageViewer1.BitmapScale - 0.01;       fDistance:=EventInfo.Distance;       Handled:=True;     end;   end; end;

　　

 

创建时间：2020.06.26　　更新时间：