title: Image canvas drawing ends up on form instead
body: <p>I'm trying to draw some custom shapes on the canvas of a TImage, but the output ends up on the TImage parent form's canvas instead.  It appears I have to convert my points from local to absolute to make this work, but that causes problems too.  See example:</p>
  
  <ul>
  <li>Does anyone know why Image.Canvas.DrawArc (etc) draws relative to the parent form instead of relative to the Image?</li>
  <li>If I go through the trouble of .LocalToAbsolute... why does the arc look so different?</li>
  </ul>
  
  <p>The project is simple: Firemonkey HD form with TPanel in the middle and TImage inside the TPanel (aligned to client).  The button just executes the code.</p>
  
  <p>Here's the code:</p>
  
  <pre><code>    unit Unit1;
  
  interface
  
  uses
    System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants, 
    FMX.Types, FMX.Graphics, FMX.Controls, FMX.Forms, FMX.Dialogs, FMX.StdCtrls,
    FMX.Objects;
  
  type
    TForm1 = class(TForm)
      Button1: TButton;
      Panel1: TPanel;
      Image1: TImage;
      procedure Button1Click(Sender: TObject);
    private
      { Private declarations }
    public
      { Public declarations }
    end;
  
  var
    Form1: TForm1;
  
  implementation
  
  {$R *.fmx}
  
  
  procedure TForm1.Button1Click(Sender: TObject);
  begin
    Image1.Canvas.BeginScene;
  
    {Trying to draw arc and line on Image's canvas - Doesn't work; it draws to Form's canvas instead}
    Image1.Canvas.DrawArc(PointF(0,0), PointF(10, 10), 0.0, 45.0, 1.0);
    Image1.Canvas.DrawLine(PointF(0.0, 0.0), PointF(100, 100), 1.0);
  
    {Trying to draw arc and line on Image's canvas - This works; by why should such steps be necessary and why is the arc so different?}
    Image1.Canvas.DrawArc(Image1.LocalToAbsolute(PointF(0,0)), Image1.LocalToAbsolute(PointF(10, 10)), 0.0, 45.0, 1.0);
    Image1.Canvas.DrawLine(Image1.LocalToAbsolute(PointF(0.0, 0.0)), Image1.LocalToAbsolute(PointF(100, 100)), 1.0);
  
    Image1.Canvas.EndScene;
  end;
  
  end.
  </code></pre>