TIECanvas.Polyline

Declaration

procedure Polyline(Points: array of TPoint); overload;
procedure Polyline(Points: array of TPoint; PointCount: Integer); overload;

Description

Draw a series of joined lines specified by multiple points.

Note:
◼For a double version use, PolylineD
◼For a polygon (closed polyline), use Polygon
◼For advanced polygon drawing, use AdvancedDrawPolyline

GDI+ Method: GdipDrawLinesI

Examples

// Draw a 5-pointed star
var
  pp: array[0..10] of TPoint;
begin
  ImageEnView1.IEBitmap.IECanvas.Pen.Color := clOrangeRed;
  ImageEnView1.IEBitmap.IECanvas.Pen.Width := 3;

  pp[0]  := Point(175, 50);
  pp[1]  := Point(205, 145);
  pp[2]  := Point(300, 145);
  pp[3]  := Point(225, 205);
  pp[4]  := Point(253, 300);
  pp[5]  := Point(175, 243);
  pp[6]  := Point(98 , 300);
  pp[7]  := Point(128, 205);
  pp[8]  := Point(50 , 145);
  pp[9]  := Point(148, 145);
  pp[10] := Point(175, 50);

  ImageEnView1.IEBitmap.IECanvas.Polyline(pp);
  ImageEnView1.Update();
end;


// Method to draw a pointer arrow from LineX1,LineY1 to LineX2, LineY2
// IEDrawLineArrow( ImageEnView1.IEBitmap.IECanvas, 650, 680, 850, 780, 30, 30, clBlack, 2, clYellow );
// ImageEnView1.Update();
procedure IEDrawLineArrow(Canvas: TIECanvas; LineX1, LineY1, LineX2, LineY2: integer; ArrowW, ArrowH: integer;
                          BorderColor: TColor; BorderWidth: Integer; FillColor: TColor);
const
  A90 = PI / 2;
var
  aa, bb, hw: double;
  pp: array[0..2] of TPoint;
  p1x, p1y: integer;
begin
  // Border
  if ( BorderColor = clNone ) or ( BorderWidth < 1 ) then
    Canvas.Pen.Style := psClear
  else
    Canvas.Pen.Style := psSolid;
  Canvas.Pen.Color := BorderColor;
  Canvas.Pen.Width := BorderWidth;

  // Fill
  if ( FillColor = clNone ) then
    Canvas.Brush.Style := bsClear
  else
    Canvas.Brush.Style := bsSolid;
  Canvas.Brush.Color := FillColor;

  Canvas.DrawLine( LineX1, LineY1, LineX2, LineY2 );

  hw := ArrowW / 2;
  aa := IEAngle( LineX1, LineY1, LineX2, LineY2, LineX1, LineY2 );
  if LineX1 = LineX2 then
    if LineY1 < LineY2 then
      aa := -A90
    else
      aa := A90;
  if ((LineX1 > LineX2) and (LineY2 < LineY1)) or ((LineX1 < LineX2) and (LineY1 < LineY2)) then
    bb := 2 * pi - aa + A90
  else
    bb := aa + A90;
  if ((LineX2 < LineX1) and (LineY2 > LineY1)) or ((LineX2 < LineX1) and (LineY2 < LineY1)) or ((LineX1 < LineX2) and (LineY1 = LineY2)) then
  begin
    p1x := LineX1 + trunc(cos(bb - A90) * ArrowH);
    p1y := LineY1 + trunc(sin(bb - A90) * ArrowH);
  end
  else
  begin
    p1x := LineX1 + trunc(cos(bb + A90) * ArrowH);
    p1y := LineY1 + trunc(sin(bb + A90) * ArrowH);
  end;

  pp[0].x := p1x + trunc(cos(bb) * hw);
  pp[0].y := p1y + trunc(sin(bb) * hw);
  pp[1].x := p1x + trunc(cos(bb + pi) * hw);
  pp[1].y := p1y + trunc(sin(bb + pi) * hw);
  pp[2].x := LineX1;
  pp[2].y := LineY1;

  Canvas.Polygon(pp);
end;

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