TIEPolylineLayer.AddCurvePoints

Declaration

procedure AddCurvePoints(StartAngle, SweepAngle: Double; EllipseWidth, EllipseHeight: Double; PtCount: Integer = 0); overload;
procedure AddCurvePoints(RadiusMult: Double; EndPoint: TPoint; PtCount: Integer = 0); overload;

Description

Add points to the end of a polyline in a curve.

Overload 1:

Parameter	Description
StartAngle	The point on the imaginary circle where we start (e.g. 0 starts at 3 on a clock face, -90 starts at 6 o'clock)
SweepAngle	The number of degrees to sweep. Negative values sweep clockwise (e.g. 360 would create a full circle, whereas is -180 would create a clockwise half circle)
EllipseWidth	The width of the imaginary circle in the range 0 - 1000 (e.g. 500 would make a circle half the width of the layer)
EllipseHeight	The width of the imaginary circle in the range 0 - 1000 (e.g. 500 would make a circle half the width of the layer)
PtCount	The number of points to add (if zero, it is calculated based on LayerCurveQuality)

Overload 2:

Parameter	Description
RadiusMult	Specify a multiplier to increase or decrease the radius of the curve. 1: Creates a curve of an exact half circle. >1 creates a shallower curve. <1 creates a bulging curve. Pass as negative to sweep clockwise
EndPoint	The location of the final point in the range 0 - 1000 (e.g. 500, 500 would put the final point in the center of the layer)
PtCount	The number of points to add (if zero, it is calculated based on LayerCurveQuality)

Note:
◼ The curve will start at the previous point, so will fail if the polyline layer does not contain points
◼ You can also convert a line to a curve by holding down the alt key when editing a polyline (i.e. when mlEditLayerPoints is set for MouseInteractLayers)
◼ For best quality, PtCount should be less than SweepAngle. Around SweepAngle/4 is typical.

Examples

// Add a 90 deg. curve from 6 o'clock to 3 o'clock (using overload 1)
polyLayer := TIEPolylineLayer( ImageEnView1.CurrentLayer );
polyLayer.AddPoint( 500, 500 );
polyLayer.AddCurvePoints( 270, 90, 500, 500, 20 );
ImageEnView1.Update();

// Add a 270 deg. curve from 6 o'clock to 3 o'clock (using overload 1)
polyLayer := TIEPolylineLayer( ImageEnView1.CurrentLayer );
polyLayer.AddPoint( 500, 500 );
polyLayer.AddCurvePoints( 270, -90, 500, 500, 20 );
ImageEnView1.Update();

// Draw a red heart
ImageEnView1.LayersAdd( ielkPolyline, 300, 300, 400, 400 );
With TIEPolylineLayer( ImageEnView1.CurrentLayer ) do
begin
  AddPoint( 100, 500 );
  AddCurvePoints( -1, Point( 500, 200 ), 20 );
  AddCurvePoints( -1, Point( 900, 500 ), 20 );
  AddPoint( 500, 1000 );

  LineWidth := 0;
  FillColor := clRed;
  PolylineClosed := True;
end;
ImageEnView1.Update();

// Draw a half circle curving downward (using overload 2)
TIEPolylineLayer( ImageEnView1.CurrentLayer ).AddPoint( 0, 500 );
TIEPolylineLayer( ImageEnView1.CurrentLayer ).AddCurvePoints( 1, Point( 1000, 500 ));

// Draw a half circle curving upward (using overload 2)
TIEPolylineLayer( ImageEnView1.CurrentLayer ).AddPoint( 0, 500 );
TIEPolylineLayer( ImageEnView1.CurrentLayer ).AddCurvePoints( -1, Point( 1000, 500 ));

// Draw a shallow smiley face (using overload 2)
TIEPolylineLayer( ImageEnView1.CurrentLayer ).AddPoint( 0, 500 );
TIEPolylineLayer( ImageEnView1.CurrentLayer ).AddCurvePoints( 3, Point( 1000, 500 ));

// Draw a shallow sad face (using overload 2)
TIEPolylineLayer( ImageEnView1.CurrentLayer ).AddPoint( 0, 500 );
TIEPolylineLayer( ImageEnView1.CurrentLayer ).AddCurvePoints( -3, Point( 1000, 500 ));

// Draw a bulging curve downward (using overload 2)
TIEPolylineLayer( ImageEnView1.CurrentLayer ).AddPoint( 0, 500 );
TIEPolylineLayer( ImageEnView1.CurrentLayer ).AddCurvePoints( 0.5, Point( 1000, 500 ));

// Draw a bulging curve upward (using overload 2)
TIEPolylineLayer( ImageEnView1.CurrentLayer ).AddPoint( 0, 500 );
TIEPolylineLayer( ImageEnView1.CurrentLayer ).AddCurvePoints( 0.5, Point( 1000, 500 ));

// Draw a blue raindrop (using overload 2)
ImageEnView1.LayersAdd( ielkPolyline, 600, 300, 400, 400 );
With TIEPolylineLayer( ImageEnView1.CurrentLayer ) do
begin
  AddPoint( 100, 500 );
  AddCurvePoints( 0.1, Point( 800, 500 ), 30 );
  AddPoint( 500, 0 );
  LineWidth := 0;
  FillColor := clSkyBlue;
  PolylineClosed := True;
end;
ImageEnView1.Update();

// Curve from 270 (6 o'clock) anti-clockwise to 180 (9 o'clock)
StartAngle := 270;
EndAngle   := 90;
SweepAngle := EndAngle - StartAngle + 360;
if SweepAngle >= 360 then
  SweepAngle := SweepAngle - 360;
TIEPolylineLayer( ImageEnView1.CurrentLayer).AddCurvePoints( StartAngle, SweepAngle, 1000, 1000, 30 );

// Draw a pink balloon
ImageEnView1.LayersAdd( ielkPolyline, 100, 100, 600, 800 );
With TIEPolylineLayer( ImageEnView1.CurrentLayer ) do
begin
  AddPoint( 500, 500 );
  AddCurvePoints( 0.95, Point( 500, 0 ));
  AddCurvePoints( 0.95, Point( 500, 500 ));
  AddPoint($FFFEE, $FFFEE);     // End shape and close polyline
  AddPoint( 500, 500 );
  AddPoint( 520, 517 );
  AddPoint( 480, 517 );
  AddPoint($FFFEE, $FFFEE);     // End shape and close polyline
  AddPoint( 500, 517 );
  AddCurvePoints( 3, Point( 500, 690 ));
  AddCurvePoints( -3, Point( 510, 850 ));
  AddCurvePoints( 3, Point( 500, 1000 ));
  AddPoint($FFFFF, $FFFFF);     // End polyline (optional at end)

  LineWidth := 2;
  FillColor := $00921CF0;
  PolylineClosed := False;
end;
ImageEnView1.Update();

TIEPolylineLayer.AddCurvePoints