阅读以下说明和Visual Basic代码，将相应文字填入(n)处，并写在对应栏内。

[说明]

以下Visual Basic代码实现了对位图(BMP)进行旋转显示。以下程序共实现了对BMP位图图形进行 180°旋转、90°旋转(顺时针)、90°旋转(逆时针)、水平翻转、垂直翻转共5项处理。显示界面如图12-8所示。仔细阅读[代码7-1]至[代码7-3]，完成(n)代码，并写在对应栏内。

[代码7-1］

Begin VB. Form. Form1

AutoRedraw =-1 'True

Caption="图像的施转"

//...窗体描述( 略 )

Begin VB. CommandButton Command7

Caption="退出"

//...窗体描述(略 )

End

Begin VB.CommandButton Command6

Caption = "复位"

//...窗体描述(略)

End

Begin VB.CommandButton Command5

Caption= "垂直翻转"

//...窗体描述(略)

End

Begin VB.CommandButton Command4

Caption="水平翻转"

//...窗体描述(略)

End

Begin VB.CommandButton Command3

Caption= "90°(逆时针)"

//...窗本描述(略)

End

Begin VB.CommandButton Command2

Caption= "90°(顺时针)"

//...窗体描述(略)

End

Begin VB.PictureBox Picture2

//...窗体描述(略)

End

Begin VB.CommandButton Command1

Caption="180°"

//...窗体描述(略)

End

Begin VB.PictureBox Picture 1

//...窗体描述(略)

End

End

[代码7-2]

Private Declare Function BitBlt Lib "gdi32" ( ByVal hDestDC As Long,

ByVal x As Long,

ByVal y As Long,

ByVal n Width As Long,

ByVal nHeight As Long,

ByVal hSrcDC As Long,

ByVal xSrc As Long,

ByVal ySrc As Long,

ByVal dwRop As Long ) As Long

Const srcopy = &HCC0020

Dim h As Integer

Dim w As Integer

Private Sub Form_Load ( )

Picture2.Picture = LoadPicture ( App.Path & "\a01.bmp") '导入图片'

h = Picture 1 .Height

w = Picture 1.Width

End Sub

[代码7-3]

Private Sub Commandl_Click ( ) 旋转180°

Picture2.Picture = LoadPicture ( "" )

For j = 0 To h Step 1

For i = 0 To w Step 1

(1)

Next i

Next j

End Sub

Private Sub Command2_Click ( ) '顺时针施转90°'

Picture2.Picture = LoadPicture ( "" )

For i-h To 0 Step-1

For j - 0 To w Step 1

(2)

Next j

Next i

End Sub

Private Sub Command3_Click ( ) '逆时针旋转90°'

Picture2.Picture = LoadPicture ("")

For j =w To 0 Step -1

For i = 0 To h Step 1

(3)

Next i

Next j

End Sub

Private