可做压力与支撑线用，也可做趋势线用，虽然有些地方定点有出入，但作为通达信的画线公式已经算是一个突破了。
{趋势画线}
N:=5;
A1:=BACKSET(ISLASTBAR,PEAKBARS(1,N,1)+1);
A2:=A1>REF(A1,1);
B1:=BACKSET(ISLASTBAR,PEAKBARS(1,N,2)+1);
B2:=B1>REF(B1,1);
C1:=BACKSET(ISLASTBAR,PEAKBARS(1,N,3)+1);
C2:=C1>REF(C1,1);

A11:=BACKSET(ISLASTBAR,TROUGHBARS(2,N,1)+1);
A21:=A11>REF(A11,1);
B11:=BACKSET(ISLASTBAR,TROUGHBARS(2,N,2)+1);
B21:=B11>REF(B11,1);
C11:=BACKSET(ISLASTBAR,TROUGHBARS(2,N,3)+1);
C21:=C11>REF(C11,1);
①:dRAWLINE(B2,H,A2,H,1),COLORBLUE;
②:dRAWLINE(C2,H,B2,H,1),COLORCC6633;
③:IF(A1,PEAK(1,N,1),DRAWNULL),COLORFFAA00;
④:dRAWLINE(C2,H,A2,H,1),COLORLIBLUE;
⑤:dRAWLINE(B21,L,A21,L,1),COLORYELLOW;
⑥:dRAWLINE(C21,L,B21,L,1),COLORFF00FF;
⑦:dRAWLINE(C21,L,A21,L,1),COLORBROWN;
⑧:IF(A11,TROUGH(2,N,1),DRAWNULL),COLORRED;