New Custom Component Crashing the IDE - delphi

Question

This is my first attempt at creating a component, I thought I would start with a very basic LED (light bulb not text), after reading a few articles I came up with the following code (which was working), I closed down the IDE (XE10.1 update2) and when trying to use the component in a new blank empty app the IDE crashes when adding the control can anybody help :
unit ZaxLED;
interface
uses
Windows, Messages, Controls, Forms, Graphics, ExtCtrls, Classes, math;
type
TZaxLED = class(TGraphicControl)
private
{ Private declarations }
FColorOn: Tcolor;
FColorOff: Tcolor;
Color: Tcolor;
FStatus: Boolean;
FOnChange: TNotifyEvent;
procedure SetColorOn(Value: Tcolor);
procedure SetColorOff(Value: Tcolor);
function GetStatus: Boolean;
procedure SetStatus(Value: Boolean);
protected
{ Protected declarations }
procedure Paint; override;
public
{ Public declarations }
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
procedure SetBounds(ALeft, ATop, AWidth, AHeight: Integer); override;
published
{ Published declarations }
property width default 17;
property height default 17;
property Align;
property Anchors;
property Constraints;
property ColorOn: Tcolor read FColorOn write SetColorOn default clLime;
property ColorOff: Tcolor read FColorOff write SetColorOff default clGray;
property Status: Boolean read GetStatus write SetStatus default True;
property OnChange: TNotifyEvent read FOnChange write FOnChange;
end;
procedure Register;
implementation
procedure Register;
begin
RegisterComponents('Samples', [TZaxLED]);
end;
{ TZaxLED }
constructor TZaxLED.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
width := 17;
height := 17;
ColorOn := clLime;
ColorOff := clGray;
Status := False;
Color := ColorOff;
end;
destructor TZaxLED.Destroy;
begin
inherited Destroy;
end;
function TZaxLED.GetStatus: Boolean;
begin
Result := FStatus;
end;
procedure TZaxLED.Paint;
var
Radius, xCenter, YCenter: Integer;
begin
if csDesigning in ComponentState then
begin
Canvas.Pen.Style := psDot;
Canvas.Brush.Style := bsClear;
Canvas.Rectangle(ClientRect);
end;
Canvas.Brush.Color := Color;
Radius := Floor(width / 2) - 2;
xCenter := Floor(width / 2);
YCenter := Floor(height / 2);
Canvas.Ellipse(xCenter - Radius, YCenter - Radius, xCenter + Radius,
YCenter + Radius);
end;
procedure TZaxLED.SetBounds(ALeft, ATop, AWidth, AHeight: Integer);
begin
if Autosize and (Align in [alNone, alCustom]) then
inherited SetBounds(ALeft, ATop, width, height)
else
inherited SetBounds(ALeft, ATop, AWidth, AHeight);
end;
procedure TZaxLED.SetColorOff(Value: Tcolor);
begin
FColorOff := Value;
if not Status then
ColorOff := Value;
end;
procedure TZaxLED.SetColorOn(Value: Tcolor);
begin
FColorOn := Value;
if Status then
ColorOn := Value;
end;
procedure TZaxLED.SetStatus(Value: Boolean);
begin
if Value <> FStatus then
begin
FStatus := Value;
if FStatus then
Color := ColorOn
else
Color := ColorOff;
if Assigned(FOnChange) then
FOnChange(Self);
end;
end;
end.
I have updated the code to take in comments from #Ari0nhh I think this is working but led is not changing color at design or runtime now
procedure TZaxLED.SetColorOff(Value: Tcolor);
begin
FColorOff := Value;
end;
procedure TZaxLED.SetColorOn(Value: Tcolor);
begin
FColorOn := Value;
end;

Answer 1

I see a number of problems with your code.
your uses clause needs cleanup. Do not create dependencies on units you do not actually use. Units that are only used by the component's internal code should be moved to the uses clause of the implementation section. The uses clause of the interface section should only refer to units that are needed to satisfy types/references directly used by your public interface.
a Color data member is being declared when there is already an inherited Color property. This data member is redundant and unnecessary, as its sole purpose is to carry the selected Status color from SetStatus() to Paint(), which is not necessary because Paint() can (and should) determine that color value directly.
the Status property is declared with a default value of True, but the property is initialized to False in the constructor.
the ColorOn and ColorOff property setters are calling themselves recursively, instead of triggering a repaint so the new state image can be shown.
The Status property setter is also not triggering a repaint.
With that said, try something more like this instead:
unit ZaxLED;
interface
uses
Classes, Controls, Graphics;
type
TZaxLED = class(TGraphicControl)
private
{ Private declarations }
FColorOn: TColor;
FColorOff: TColor;
FStatus: Boolean;
FOnChange: TNotifyEvent;
procedure SetColorOn(Value: TColor);
procedure SetColorOff(Value: TColor);
procedure SetStatus(Value: Boolean);
protected
{ Protected declarations }
procedure Paint; override;
public
{ Public declarations }
constructor Create(AOwner: TComponent); override;
procedure SetBounds(ALeft, ATop, AWidth, AHeight: Integer); override;
published
{ Published declarations }
property Width default 17;
property Height default 17;
property Align;
property Anchors;
property Constraints;
property ColorOn: TColor read FColorOn write SetColorOn default clLime;
property ColorOff: TColor read FColorOff write SetColorOff default clGray;
property Status: Boolean read FStatus write SetStatus default False;
property OnChange: TNotifyEvent read FOnChange write FOnChange;
end;
procedure Register;
implementation
uses
Math;
procedure Register;
begin
RegisterComponents('Samples', [TZaxLED]);
end;
{ TZaxLED }
constructor TZaxLED.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
FColorOn := clLime;
FColorOff := clGray;
FStatus := False;
Width := 17;
Height := 17;
end;
procedure TZaxLED.Paint;
var
Radius, xCenter, YCenter: Integer;
begin
if csDesigning in ComponentState then
begin
Canvas.Pen.Style := psDot;
Canvas.Brush.Style := bsClear;
Canvas.Rectangle(ClientRect);
end;
if FStatus then
Canvas.Brush.Color := FColorOn
else
Canvas.Brush.Color := FColorOff;
Radius := Floor(Width / 2) - 2;
xCenter := Floor(Width / 2);
YCenter := Floor(Height / 2);
Canvas.Ellipse(xCenter - Radius, YCenter - Radius, xCenter + Radius, YCenter + Radius);
end;
procedure TZaxLED.SetBounds(ALeft, ATop, AWidth, AHeight: Integer);
begin
if AutoSize and (Align in [alNone, alCustom]) then
begin
AWidth := Width;
AHeight:= Height;
end;
inherited SetBounds(ALeft, ATop, AWidth, AHeight);
end;
procedure TZaxLED.SetColorOff(Value: TColor);
begin
if FColorOff <> Value then
begin
FColorOff := Value;
if not FStatus then Invalidate;
end;
end;
procedure TZaxLED.SetColorOn(Value: TColor);
begin
if FColorOn <> Value then
begin
FColorOn := Value;
if FStatus then Invalidate;
end;
end;
procedure TZaxLED.SetStatus(Value: Boolean);
begin
if Value <> FStatus then
begin
FStatus := Value;
Invalidate;
if Assigned(FOnChange) then
FOnChange(Self);
end;
end;
end.

Answer 2

Lets consider this code:
procedure TZaxLED.SetColorOff(Value: Tcolor);
begin
FColorOff := Value;
if not Status then
ColorOff := Value;
end;
An assignment of the property ColorOff will call a SetColorOff method. Which will again assign a ColorOff property. Since there is no way to break this assignment cycle, everything will end up with a stack overflow pretty fast.