unit Unit2;

interface

uses

  System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants,

  FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, FMX.Dialogs,math,FMX.Surfaces,

  FMX.Controls.Presentation, FMX.StdCtrls, FMX.Objects;

type

  TForm2 = class(TForm)

    Button1: TButton;

    Image1: TImage;

    OpenDialog1: TOpenDialog;

    Image2: TImage;

    Timer1: TTimer;

    Label1: TLabel;

    procedure Button1Click(Sender: TObject);

    procedure Timer1Timer(Sender: TObject);

  private

    class function  BitmapCompress(ABitmap: TBitmap): TBitmap;

    { Private declarations }

  public

    { Public declarations }

  end;

var

  Form2: TForm2;

implementation

{$R *.fmx}

{ TForm2 }

class function TForm2.BitmapCompress(ABitmap: TBitmap): TBitmap; //耗时耗内存，待优化

var

  SaveParams:TBitmapCodecSaveParams;

  Astream,bstream:TMemorystream;

  Surf: TBitmapSurface;

  intoldSize:Int64;

  CompressQuality:integer;

  BBitmap:TBitmap;

  ratio:double;

begin

   Astream:=TMemorystream.Create;

   Bstream:=TMemorystream.Create;

   BBitmap:=TBitmap.Create;

   ABitmap.SaveToStream(Astream);

   //ratio:=Astream.Size/1024;

  // ratio:= 10000/ratio;

   //CompressQuality:=ceil(10000/ratio);

  // if Astream.Size/1024>4096 then

  //    CompressQuality:=5

    if Astream.Size/1024>2048 then    //大图小于15之后失真严重

      CompressQuality:=15

    else if Astream.Size/1024>1024 then

      CompressQuality:=20

    else if Astream.Size/1024>512 then

      CompressQuality:=50

    else if Astream.Size/1024>256 then

      CompressQuality:=60

    else if Astream.Size/1024>128 then

      CompressQuality:=70

    else if Astream.Size/1024<50 then

      CompressQuality:=100

    else

      CompressQuality:=80;

   //showmessage(CompressQuality.ToString);

   SaveParams.Quality:=CompressQuality;

   Surf:=TBitmapSurface.Create;

   Surf.Assign(Abitmap);

   try

      if not TBitmapCodecManager.SaveToStream(bStream, Surf, 'jpg',@SaveParams) then

      begin

        showmessage('图片压缩失败！');

        exit;

      end;

    except

      showmessage('图片压缩意外错误！');

      exit;

    end;

    try

      if Astream.Size<Bstream.Size then

      begin

       // Astream.SaveToFile('d:\2.jpg');

        BBitmap.LoadFromStream(Astream);

      end

      else

      begin

       // bstream.SaveToFile('d:\2.jpg');

        BBitmap.LoadFromStream(bstream);

      end;

    except

      showmessage('图片存储失败！');

      exit;

    end;

    BBitmap.SaveToFile('d:\1111.jpg');

    result:= BBitmap;

end;

procedure TForm2.Button1Click(Sender: TObject);

var

  ABitmap:Tbitmap;

  StartTime,EndTime:cardinal;

begin

  ABitmap :=FMX.Graphics.TBitmap.Create;

    opendialog1.filter:='图片文件(*.bmp;*.png;*.jpeg;*.jpg)|*.bmp;*.png;*.jpeg;*.jpg';

    if OpenDialog1.Execute then

    begin

    //StartTime:=GetTickCount;

      ABitmap.LoadFromFile(OpenDialog1.FileName);

     //  Timer1.Enabled:=true;

      image1.Bitmap.LoadFromFile(OpenDialog1.FileName);

     image2.Bitmap.Assign(BitmapCompress(ABitmap));

    end;

  //Timer1.Enabled:=false;

end;

procedure TForm2.Timer1Timer(Sender: TObject);

var

  BeginCount,Endcount,StartCount:Cardinal;

begin

//    BeginCount:=GetTickCount;//只适用于windows，还没有找到移动端方法计算程序运行时间

end;

end.