用VB设计一个蝴蝶飞动的程序

因为这里只能上传一张图片，所以写了一个单张图片的。装载系列图片的我也写了，只是窗体初始化会很麻烦。以下代码是实现单张图片的随意飞舞程序，能做到：

1、碰到窗体边缘时，图片会自动改变飞舞的方向（题意中要求的“返回”，只能是在一条线上来回移动，本程序实现蝴蝶出发位置随意，能在窗体内四处飞舞），而且头部也会跟着改变方向

2、窗体改变大小时，蝴蝶不会消失不见，会立即在新的窗体内继续飞舞

'建一个Picture1控件，在它的属性对话框内设置Appearance=0?AutoRedraw=True?AutoSize=True?BorderStyle=0，然后在它的Picture中加载蝴蝶图片

'再建一个Picture2控件，在它的属性对话框内设置Appearance=0?AutoRedraw=False?AutoSize=False?BorderStyle=0，其他默认属性都不得改变

'Form的BackColor设为与蝴蝶图片的背景色一致，本程序中，即&H80000009&

'再加一个Timer1控件

Private?Const?Pi?=?3.1415926535

Private?Declare?Function?SetPixel?Lib?"gdi32"?(ByVal?hdc?As?Long,?ByVal?x?As?Long,?ByVal?y?As?Long,?ByVal?crColor?As?Long)?As?Long

Private?Declare?Function?GetPixel?Lib?"gdi32"?(ByVal?hdc?As?Long,?ByVal?x?As?Long,?ByVal?y?As?Long)?As?Long

Dim?x0!,?y0!,?x1!,?x2!,?y1!,?y2!,?foot!,?zt%?'x0和y0是图片框长高，(x1,y1)-(x2,y2)是窗体坐标系，foot是蝴蝶移动步长，zt是蝴蝶飞舞的线路标记

Dim?k!?'k或1/k是飞行轨迹的斜率

Dim?flag?As?Boolean?'flag判断是顺时针还是逆时针飞舞

Private?Sub?bmp_rotate(pic1?As?PictureBox,?pic2?As?PictureBox,?ByVal?theta?As?Single)?'自定义角度旋转图片

Dim?c1x?As?Integer,?c1y?As?Integer

Dim?c2x?As?Integer,?c2y?As?Integer

Dim?a?As?Single

Dim?p1x?As?Integer,?p1y?As?Integer

Dim?p2x?As?Integer,?p2y?As?Integer

Dim?n?As?Integer,?r?As?Integer

c1x?=?pic1.ScaleWidth?/?2

c1y?=?pic1.ScaleHeight?/?2

c2x?=?pic2.ScaleWidth?/?2

c2y?=?pic2.ScaleHeight?/?2

If?c2x?<?c2y?Then?n?=?c2y?Else?n?=?c2x

n?=?n?-?1

pic1hDC&?=?pic1.hdc

pic2hDC&?=?pic2.hdc

For?p2x?=?0?To?n

For?p2y?=?0?To?n

If?p2x?=?0?Then?a?=?Pi?/?2?Else?a?=?Atn(p2y?/?p2x)

r?=?Sqr(1&?*?p2x?*?p2x?+?1&?*?p2y?*?p2y)

p1x?=?r?*?Cos(a?+?theta)

p1y?=?r?*?Sin(a?+?theta)

c0&?=?GetPixel(pic1hDC,?c1x?+?p1x,?c1y?+?p1y)

c1&?=?GetPixel(pic1hDC,?c1x?-?p1x,?c1y?-?p1y)

c2&?=?GetPixel(pic1hDC,?c1x?+?p1y,?c1y?-?p1x)

c3&?=?GetPixel(pic1hDC,?c1x?-?p1y,?c1y?+?p1x)

If?c0&?<>?-1?Then?xret&?=?SetPixel(pic2hDC,?c2x?+?p2x,?c2y?+?p2y,?c0&)

If?c1&?<>?-1?Then?xret&?=?SetPixel(pic2hDC,?c2x?-?p2x,?c2y?-?p2y,?c1&)

If?c2&?<>?-1?Then?xret&?=?SetPixel(pic2hDC,?c2x?+?p2y,?c2y?-?p2x,?c2&)

If?c3&?<>?-1?Then?xret&?=?SetPixel(pic2hDC,?c2x?-?p2y,?c2y?+?p2x,?c3&)

Next

t%?=?DoEvents()

Next

End?Sub

Private?Sub?Place(ByVal?picnum?As?Integer,?ByVal?x?As?Single,?ByVal?y?As?Single)?'控制两个图片框的位置

If?picnum?=?1?Then

Picture1.Left?=?x

Picture1.Top?=?y

Else

Picture2.Left?=?x

Picture2.Top?=?y

End?If

End?Sub

Private?Sub?Direct(ByVal?angle?As?Integer)?'按指定角度旋转图片，angle是角度

angle?=?angle?Mod?360

hudu?=?(Pi?*?angle?*?1#)?/?(180?*?1#)?'弧度

bmp_rotate?Picture1,?Picture2,?hudu

End?Sub

Private?Sub?Form_Activate()

x1?=?0!

x2?=?10000!

y1?=?0!

y2?=?10000!

Me.Scale?(x1,?y1)-(x2,?y2)

Randomize

Picture1.ScaleMode?=?3

Picture2.ScaleMode?=?3

x0?=?Picture1.Width

Picture2.Width?=?x0

y0?=?Picture1.Height

Picture2.Height?=?y0

Picture1.Visible?=?True

Picture2.Visible?=?False

x?=?Int(1000?+?(x2?-?x1?-?x0?-?1000)?*?Rnd)?'蝴蝶出发处的横坐标

y?=?Int(1000?+?(y2?-?y1?-?y0?-?1000)?*?Rnd)?'蝴蝶出发处的纵坐标

k?=?y?/?x?'k为撞向水平边框或离开竖直边框的斜率，1/k则为撞向竖直边框或离开水平边框的斜率

Place?1,?-x2,?y2?-?y0?'将图片框的复制源移出窗体的可见范围，但Visible属性又必须是True，否则复制图片会失败

Place?2,?x,?y?'初始化蝴蝶的出发位置

Timer1.Enabled?=?True

Timer1.Interval?=?100?'定义移动周期

zt?=?0

End?Sub

Private?Sub?Form_Click()

Timer1.Enabled?=?Not?Timer1.Enabled

End?Sub

Private?Sub?Form_Resize()?'窗体改变大小时，坐标系需要重新定义

x1?=?0!

x2?=?10000!

y1?=?0!

y2?=?10000!

Me.Scale?(x1,?y1)-(x2,?y2)

Cls

x0?=?Picture1.Width

Picture2.Width?=?x0

y0?=?Picture1.Height

Picture2.Height?=?y0

'如果蝴蝶在窗体外，则立即召回

If?Picture2.Left?<?x1?Then?Place?2,?x1,?Picture2.Top

If?Picture2.Top?<?y1?Then?Place?2,?Picture2.Left,?y1

If?Picture2.Left?>?x2?-?x1?-?x0?Then?Place?2,?x2?-?x1?-?x0,?Picture2.Top

If?Picture2.Top?>?y2?-?y1?-?y0?Then?Place?2,?Picture2.Left,?y2?-?y1?-?y0

End?Sub

Private?Sub?Form_Unload(Cancel?As?Integer)

End

End?Sub

'zt=0,1,2,3时，分别表示顺时针向右上（简称顺右上）或逆左下，顺右下或逆左上，顺左下或逆右上，顺左上或逆右下

Private?Sub?Timer1_Timer()

foot?=?100

x?=?Picture2.Left:?y?=?Picture2.Top

Select?Case?True

Case?(flag?=?True?And?zt?=?0)?Or?(flag?=?False?And?zt?=?2)

Place?2,?x?+?foot,?y?-?k?*?foot

'Line?(x,?y)-(x?+?foot,?y?-?k?*?foot)

Direct?360

If?Picture2.Left?>?x2?-?x1?-?x0?-?foot?Then?zt?=?1:?flag?=?False?'撞到垂直边框，将逆左上

If?Picture2.Top?<?foot?Then?zt?=?1:?flag?=?True?'撞到水平边框，将顺右下

Case?(flag?=?True?And?zt?=?1)?Or?(flag?=?False?And?zt?=?3)

Place?2,?x?+?foot,?y?+?foot?/?k

'Line?(x,?y)-(x?+?foot,?y?+?foot?/?k)

Direct?270

If?Picture2.Left?>?x2?-?x1?-?x0?-?foot?Then?zt?=?2:?flag?=?True?'撞到垂直边框，将顺左下

If?Picture2.Top?>?y2?-?y1?-?y0?-?foot?Then?zt?=?2:?flag?=?False?'撞到水平边框，将逆右上

Case?(flag?=?True?And?zt?=?2)?Or?(flag?=?False?And?zt?=?0)

Place?2,?x?-?foot,?y?+?k?*?foot

'Line?(x,?y)-(x?-?foot,?y?+?k?*?foot)

Direct?180

If?Picture2.Left?<?foot?Then?zt?=?3:?flag?=?False?'撞到垂直边框，将逆右下

If?Picture2.Top?>?y2?-?y1?-?y0?-?foot?Then?zt?=?3:?flag?=?True?'撞到水平边框，将顺左上

Case?(flag?=?True?And?zt?=?3)?Or?(flag?=?False?And?zt?=?1)

Place?2,?x?-?foot,?y?-?foot?/?k

'Line?(x,?y)-(x?-?foot,?y?-?foot?/?k)

Direct?90

If?Picture2.Left?<?foot?Then?zt?=?0:?flag?=?True?'撞到垂直边框，将顺右上

If?Picture2.Top?<?foot?Then?zt?=?0:?flag?=?False?'撞到水平边框，将逆左下

End?Select

Picture2.Visible?=?True

End?Sub