Android实例GestureManager手势支持放大缩小左右移动上下移动

相关资料：

https://download.csdn.net/download/zhujianqiangqq/62483987         代码包下载

实例代表：

Unit1.fmx

界面中有三个图片，太大不方便上传，请从CSDN上下载代码包。

Unit1.pas

unit Unit1;

interface

uses
  System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants,
  FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, FMX.Dialogs,
  FMX.Controls.Presentation, FMX.StdCtrls, FMX.Gestures, FMX.TabControl,
  FMX.Objects
  ,System.Generics.Collections
  ,System.Math, FMX.Layouts
  ;

type
  TForm1 = class(TForm)
    GestureManager1: TGestureManager;
    Image1: TImage;
    Rectangle1: TRectangle;
    Layout1: TLayout;
    Image2: TImage;
    Layout2: TLayout;
    Image3: TImage;
    Image4: TImage;
    Label1: TLabel;
    procedure FormGesture(Sender: TObject; const EventInfo: TGestureEventInfo;
      var Handled: Boolean);
    procedure Image2Click(Sender: TObject);
  private
   { Private declarations }
    FLastPosition       : TPointF;
    FLastDIstance       : integer ;
    FOriginalWidth      : Single ;
    LImage: TImage;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.fmx}

procedure TForm1.FormGesture(Sender: TObject;
  const EventInfo: TGestureEventInfo; var Handled: Boolean);
var
  LObj: IControl;
  LImageCenter: TPointF;
  Tan :single;
  A,B :single;
begin
  inherited;

  Label1.Text := IntToStr(EventInfo.GestureID);
  if EventInfo.GestureID = igiZoom then//放大缩小手势
  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
        LImage := TImage(LObj.GetObject);
        LImageCenter := LImage.Position.Point + PointF(LImage.Width / 2, LImage.Height / 2);
        if LImage.Width<FOriginalWidth then
        begin
          LImage.Width := LImage.Width +  (power(2,(EventInfo.Distance - FLastDistance)/10)-1)*10; // 控制u图片缩小速度和大小，滑的越大变化越小，后面变化无限小
          LImage.Height := LImage.Height + (power(2,(EventInfo.Distance - FLastDistance)/10)-1)*10;//
        end
        else
        begin
          LImage.Width := LImage.Width +  2*(EventInfo.Distance - FLastDistance);
          LImage.Height := LImage.Height + 2*(EventInfo.Distance - FLastDistance);
        end;
        LImage.Position.X := LImageCenter.X - LImage.Width / 2;
        LImage.Position.Y := LImageCenter.Y - LImage.Height / 2;
      end;
      FLastDistance := EventInfo.Distance;
    end;
    Exit;
  end;

  //平移
  if EventInfo.GestureID = igiPan then
  begin
    LObj := Self.ObjectAtPoint(ClientToScreen(EventInfo.Location));
    if LObj is TImage then
    begin
      if not(TInteractiveGestureFlag.gfBegin in EventInfo.Flags) then
      begin
        LImage := TImage(LObj.GetObject);
        if (LImage <> nil) then
        begin
          LImage.Position.X := LImage.Position.X + (EventInfo.Location.X - FLastPosition.X);
          LImage.Position.Y := LImage.Position.Y + (EventInfo.Location.Y - FLastPosition.Y);
        end;
      end;
      FLastPosition := EventInfo.Location;
      Exit;
    end;
  end;
end;

procedure TForm1.Image2Click(Sender: TObject);
var
  oImage: TImage;
begin
  if Sender is TImage then
  begin
    oImage := (Sender as TImage);
    Image1.Bitmap.Assign(oImage.Bitmap);
  end;
end;

end.