Procedure TLINEITEM.DRAW (Acanvas: Tcanvas);
VAR
XA, Ya, XB, YB: REAL
D: Real;
X1, Y1, X0, Y0: Integer;
Begin
Acanvas.pen.style: = pssolid;
Acanvas.pen.color: = CLWHITE;
// Painted straight line
Acanvas.moveto (Ptstart.x, Ptstart.y);
Acanvas.lineto (Ptend.x, Ptend.y);
// Painted arrows
X0: = ptstart.x; // ptstart is the starting point of the arrow, Ptend is the end, all TPOINT type
Y0: = ptstart.y;
X1: = ptend.x;
Y1: = ptend.y;
D: = SQRT ((Y1 - Y0) * (Y1 - Y0) (x1 - x0) * (x1 - x0));
IF D> 0 THEN BEGIN
XA: = x1 arrowlen * ((x0 - x1) (Y0 - Y1) / 2) / D;
Ya: = Y1 Arrowlen * ((Y0 - Y1) - (X0 - X1) / 2) / D;
XB: = x1 arrowlen * ((x0 - x1) - (Y0 - Y1) / 2) / D;
YB: = Y1 Arrowlen * ((Y0 - Y1) (X0 - X1) / 2) / D;
Acanvas.moveto (Ptend.x, Ptend.y);
Acanvas.LineTo (Trunc (Xa), Trunc (YA);
Acanvas.moveto (Ptend.x, Ptend.y);
Acanvas.LineTo (Trunc (XB), Trunc (YB);
END;
// If you select a focus rectangle, you can
IF fselected = true kilin
Acanvas.Rectangle (Ptstart.x - forcusRange),
(Ptstart.y - forcusrange),
(Ptstart.x forcusRange),
(PTStart.y forcusrange))));
Acanvas.Rectangle (Ptend.x - forcusRange),
(Ptend.y - forcusrange),
(Ptend.x forcusrange),
(Ptend.y forcusrange));
END;
END;
Canvas is any Canvas with a component with a brush. The specific geometry is not explained by the original author. However, after the bottom check. There are three characteristics.
1. Arrow two-wing endpoints and straight lines vertical (the gum of slope is equal to -1).
2. The length of the arrow is the same length. (Equal waist triangle)
3. Arrow two wings lengths and distance ratios between the two-wing ends. (Determined angle)
