I’m still inexperienced at Delphi for Android, but I keep hitting brick walls.

My latest problem is using TBitmap.CopyFromBitmap() in Delphi 12 CE.

When I use it, the destination bitmap seems to be cleared and then the bitmap section is copied correctly.

In the simple example, I have two bitmaps of different colors (yellow and purple), and pressing the button copies a small block from the right image to the left. Note how the yellow disappears.

Please tell me why I am battling with such a trivial task.

unit testUnit;

interface

uses
  System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants,
  FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, FMX.Dialogs, FMX.Objects,
  FMX.Controls.Presentation, FMX.StdCtrls;

type
  TForm1 = class(TForm)
    Image1: TImage;
    Image2: TImage;
    Button1: TButton;
    procedure FormCreate(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.fmx}

procedure TForm1.Button1Click(Sender: TObject);
var
  r:Trect;
begin
  r:=trect.Create(50,50,100,100);
   image1.Bitmap.CopyFromBitmap(image2.bitmap,r,100,150);
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
   image1.bitmap.SetSize(300,300);
   image1.bitmap.Canvas.BeginScene;
   image1.bitmap.Canvas.Clear($ffff00);
   image1.bitmap.Canvas.EndScene;
   image2.bitmap.SetSize(300,300);
   image2.bitmap.Canvas.BeginScene;
   image2.bitmap.Canvas.Clear($ff00ff);
   image2.bitmap.Canvas.EndScene;

end;

end.