VB备忘录（16）图像处理

保存图片：

SavePicture  Picture,strFileName

      把Picture保存到指定位置的图片文件中StrFileName

      注意：对于绘制的图片保存有两个要点：

                  1、AutoRedraw为真，这样才是持久图形，才会在内存中有映像，保存时就会提取它来保存。

                  2、可以picture和image ，picture是实际的图片。image则是映像画布的大小，不管是否占满PictureBox框，也会整个保存下来。

图像剪切

利用PictureClip控件进行剪切部分图片。

下例中注意：剪切的是本身的图片，而不是Picture1中的，Picture1只是为了演示“剪切区”，达到“即切即现”的效果。

Public x1     As Single, y1 As SinglePublic x2     As Single, y2 As SinglePublic xcolor As Long '异或色Private Sub Form_Load()    xcolor = vbGreen    Picture1.ScaleMode = vbPixels '像素单位    Picture2.ScaleMode = vbPixels    Picture1.DrawMode = vbXorPen  '异或方式，利用异或进行擦除End SubPrivate Sub Picture1_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)    If Button = vbLeftButton Then        x1 = X        y1 = Y        x2 = X        y2 = Y    End IfEnd SubPrivate Sub Picture1_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)    If Button = vbLeftButton Then        Picture1.Line (x1, y1)-(x2, y2), xcolor, B '第一次时画，后面相应为擦除        Picture1.Line (x1, y1)-(X, Y), xcolor, B        x2 = X        y2 = Y    End IfEnd SubPrivate Sub Picture1_MouseUp(Button As Integer, Shift As Integer, X As Single, Y As Single)    If Button = vbLeftButton Then        Picture1.Line (x1, y1)-(X, Y), xcolor, B '对最后一个进行擦除        PictureClip1.ClipX = IIf(x1 < X, x1, X)        PictureClip1.ClipY = IIf(y1 < Y, y1, Y)        PictureClip1.ClipWidth = Abs(x1 - X)        PictureClip1.ClipHeight = Abs(y1 - Y)        Picture2.Picture = PictureClip1.Clip    End IfEnd SubPrivate Sub Toolbar1_ButtonClick(ByVal Button As MSComctlLib.Button)    Select Case Button.Index        Case 1            CommonDialog1.Filter = "JPG文件(*.jpg)|*.jpg"            CommonDialog1.ShowOpen            If CommonDialog1.FileName <> "" Then                Picture1.Picture = LoadPicture(CommonDialog1.FileName)                PictureClip1.Picture = Picture1.Picture '重要，否则出错            End If        Case 3            CommonDialog1.Filter = "JPG文件(*.jpg)|*.jpg"            CommonDialog1.ShowSave            If CommonDialog1.FileName <> "" Then                SavePicture Picture2.Image, CommonDialog1.FileName            End If        Case 5            End    End SelectEnd Sub

平铺图像：

Private Sub Command1_Click()    Dim i      As Integer, j As Integer    Dim pWidth As Long, pHeight As Long    pWidth = Form1.ScaleX(Form1.Picture.Width, vbHimetric, vbPixels)    pHeight = Form1.ScaleY(Form1.Picture.Height, vbHimetric, vbPixels)    i = 0    j = 0    Do While (j * pHeight < ScaleHeight)        Do While (i * pWidth < ScaleWidth)            Form1.PaintPicture Form1.Picture, i * pWidth, j * pHeight            i = i + 1        Loop        i = 0        j = j + 1    LoopEnd SubPrivate Sub Form_Load()    Form1.ScaleMode = vbPixelsEnd Sub