TMSFNCTreeview

FNC TMS FNC UI Pack
1

Using the TreeView on macOS I get the following messages in the PAServer window:

...Nov  7 15:19:04  Project1[3473] <Error>: CGContextSaveGState: invalid context 0x0. If you want to see the backtrace, please set CG_CONTEXT_SHOW_BACKTRACE environmental variable.Nov  7 15:19:04  Project1[3473] <Error>: CGContextRestoreGState: invalid context 0x0. If you want to see the backtrace, please set CG_CONTEXT_SHOW_BACKTRACE environmental variable.Nov  7 15:19:04  Project1[3473] <Error>: CGContextSaveGState: invalid context 0x0. If you want to see the backtrace, please set CG_CONTEXT_SHOW_BACKTRACE environmental variable.Nov  7 15:19:04  Project1[3473] <Error>: CGContextRestoreGState: invalid context 0x0. If you want to see the backtrace, please set CG_CONTEXT_SHOW_BACKTRACE environmental variable.

<o:p></o:p>

Place the TreeView to an TForm, add a TButton with the following code in the OnClick() event:

procedure TForm1.Button1Click(Sender: TObject);var  i : Integer;begin  TreeView.BeginUpdate;  for i := 1 to 1000 do     TreeView.AddNode(nil).Text[0] := 'Test with <b>bold</b><br/>New Line';  TreeView.EndUpdate;end;
run it on macOS, click on the Button and scroll to the end.
Click at some lines.


2

Hi, 


We are not able to reproduce this issue here, with the above sample code.
Are you setting additional properties in the object inspector, or is this reproducible with a default TTMSFNCTreeView on the form? Which RAD Studio and macOS version are you using specifically?
3
Yes just drop the TreeView and add this code.

I'm using Delphi 10.1 Berlin Update 2. Version 24.0.25048.9432. 
On Mac side: macOS 10.11.6
4

We have used this code and tested this in Tokyo, where it is no longer reproducible. I suggest to test this in Tokyo or upgrade where this issue no longer occurs.

5
Quick check on Berlin. Here the callstack:

FMX.Canvas.Mac.TQuartzCanvasSaveState.Assign($79C65F0)
:004479cb TQuartzCanvasSaveState.Assign + $47
FMX.TMSFNCGraphics.General.TTMSFNCGraphicsContextGeneral.SaveState($7CC0B70)
FMX.TMSFNCGraphics.TTMSFNCGraphics.SaveState(True)
FMX.TMSFNCGraphics.TTMSFNCGraphics.InternalDrawText((22,5, 265,5, 189,33332824707, 286,5, ((22,5, 265,5), 22,5, 265,5), ((189,33332824707, 286,5), 189,33332824707, 286,5)),'Test with <b>bold</b><br/>New Line','','','',False,gtaLeading,gtaCenter,gttNone,0,-1,-1,True,True,74,267)
FMX.TMSFNCGraphics.TTMSFNCGraphics.DrawText((22,5, 265,5, 189,33332824707, 286,5, ((22,5, 265,5), 22,5, 265,5), ((189,33332824707, 286,5), 189,33332824707, 286,5)),'Test with <b>bold</b><br/>New Line','','','',False,gtaLeading,gtaCenter,gttNone,0,-1,-1,True,True,74,267)
FMX.TMSFNCGraphics.TTMSFNCGraphics.DrawText((22,5, 265,5, 189,33332824707, 286,5, ((22,5, 265,5), 22,5, 265,5), ((189,33332824707, 286,5), 189,33332824707, 286,5)),'Test with <b>bold</b><br/>New Line',False,gtaLeading,gtaCenter,gttNone,0,-1,-1,True,True,74,267)
FMX.TMSFNCCustomTreeView.TTMSFNCCustomTreeView.XYToNodeAnchor($7D1A4E0,74,267)
FMX.TMSFNCCustomTreeView.TTMSFNCCustomTreeView.HandleMouseDown(mbLeft,[ssLeft],74,267)
...
The Delphi code is the same in Tokio. No check to the context:


procedure TQuartzCanvasSaveState.Assign(Source: TPersistent);
begin
  inherited Assign(Source);
  if Source is TCanvasQuartz then
    CGContextSaveGState(TCanvasQuartz(Source).Context);
end;
6

Hi, 


Looking at the code in TQuartzCanvasSaveState it seems to be a crucial mistake in not checking if the Context is still assigned when assigning a source. This should at the very least be handled by the FMX framework. We'll investigate if we can find a workaround, after we can determine how to reproduce the error.