/** */
/**
* 画带箭头的线
*
*/
public
void
paintk(GC g,
int
x1,
int
y1,
int
x2,
int
y2)
{
double
H
=
10
;
//
箭头高度
double
L
=
7
;
//
底边的一半
int
x3
=
0
;
int
y3
=
0
;
int
x4
=
0
;
int
y4
=
0
;
double
awrad
=
Math.atan(L
/
H);
//
箭头角度
double
arraow_len
=
Math.sqrt(L
*
L
+
H
*
H);
//
箭头的长度
double
[] arrXY_1
=
rotateVec(x2
-
x1, y2
-
y1, awrad,
true
, arraow_len);
double
[] arrXY_2
=
rotateVec(x2
-
x1, y2
-
y1,
-
awrad,
true
, arraow_len);
double
x_3
=
x2
-
arrXY_1[
0
];
//
(x3,y3)是第一端点
double
y_3
=
y2
-
arrXY_1[
1
];
double
x_4
=
x2
-
arrXY_2[
0
];
//
(x4,y4)是第二端点
double
y_4
=
y2
-
arrXY_2[
1
];
Double X3
=
new
Double(x_3);
x3
=
X3.intValue();
Double Y3
=
new
Double(y_3);
y3
=
Y3.intValue();
Double X4
=
new
Double(x_4);
x4
=
X4.intValue();
Double Y4
=
new
Double(y_4);
y4
=
Y4.intValue();
//
g.setColor(SWT.COLOR_WHITE);
//
画线
g.drawLine(x1, y1, x2, y2);
//
画箭头的一半
g.drawLine(x2, y2, x3, y3);
//
画箭头的另一半
g.drawLine(x2, y2, x4, y4);
}
/** */
/**
*取得箭头的绘画范围
*/
public
double
[] rotateVec(
int
px,
int
py,
double
ang,
boolean
isChLen,
double
newLen)
{
double
mathstr[]
=
new
double
[
2
];
//
矢量旋转函数，参数含义分别是x分量、y分量、旋转角、是否改变长度、新长度
double
vx
=
px
*
Math.cos(ang)
-
py
*
Math.sin(ang);
double
vy
=
px
*
Math.sin(ang)
+
py
*
Math.cos(ang);
if
(isChLen)
{
double
d
=
Math.sqrt(vx
*
vx
+
vy
*
vy);
vx
=
vx
/
d
*
newLen;
vy
=
vy
/
d
*
newLen;
mathstr[
0
]
=
vx;
mathstr[
1
]
=
vy;
}
return
mathstr;
}
posted on 2007-09-21 09:39
JJCEA 阅读(5287)
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swt日记