本节主要从代码介绍Bitmap的几个方法。

设计界面：

为了便于观察，请将PicDest的SizeMode设置为：AutoSize。

cbRotateFlip的Items属性设置为RotateFlipType的成员名称：

主要代码：

    '窗体级变量，保存加载的图片
    Dim sourceImg As Bitmap

    '载入图片
    Private Sub btnLoadimg_Click(sender As Object,e As EventArgs) Handles btnLoadimg.Click
        sourceImg = New Bitmap("d:\15z.jpg")
        '或者：
        'sourceImg = Image.FromFile("d:\15z.jpg")
        picSource.Image = sourceImg
    End Sub

    '旋转、翻转
    Private Sub cbRotateFlip_SelectedIndexChanged(sender As Object,e As EventArgs) Handles cbRotateFlip.SelectedIndexChanged
        Dim destImg As Bitmap
        destImg = sourceImg.Clone
        Select Case cbRotateFlip.Text
            Case "Rotate180FlipX"
                destImg.RotateFlip(RotateFlipType.Rotate180FlipX)
            Case "Rotate180FlipNone"
                destImg.RotateFlip(RotateFlipType.Rotate180FlipNone)
            Case "Rotate180FlipXY"
                destImg.RotateFlip(RotateFlipType.Rotate180FlipXY)
            Case "Rotate180FlipY"
                destImg.RotateFlip(RotateFlipType.Rotate180FlipY)
            Case "Rotate270FlipNone"
                destImg.RotateFlip(RotateFlipType.Rotate270FlipNone)
            Case "Rotate270FlipX"
                destImg.RotateFlip(RotateFlipType.Rotate270FlipX)
            Case "Rotate270FlipXY"
                destImg.RotateFlip(RotateFlipType.Rotate270FlipXY)
            Case "Rotate90FlipNone"
                destImg.RotateFlip(RotateFlipType.Rotate90FlipNone)
            Case "Rotate90FlipX"
                destImg.RotateFlip(RotateFlipType.Rotate90FlipX)
            Case "Rotate90FlipXY"
                destImg.RotateFlip(RotateFlipType.Rotate90FlipXY)
            Case "Rotate90FlipY"
                destImg.RotateFlip(RotateFlipType.Rotate90FlipY)
            Case "RotateNoneFlipNone"
                destImg.RotateFlip(RotateFlipType.RotateNoneFlipNone)
            Case "RotateNoneFlipX"
                destImg.RotateFlip(RotateFlipType.RotateNoneFlipX)
            Case "RotateNoneFlipXY"
                destImg.RotateFlip(RotateFlipType.RotateNoneFlipXY)
            Case "RotateNoneFlipY"
                destImg.RotateFlip(RotateFlipType.RotateNoneFlipY)
        End Select
        picDest.Image = destImg
    End Sub

    '保存图片
    Private Sub btnSave_Click(sender As Object,e As EventArgs) Handles btnSave.Click
        picDest.Image.Save("d:\1515.jpg",Imaging.ImageFormat.Jpeg)
    End Sub

运行效果：

由于.net平台下C#和vb.NET很相似，本文也可以为C#爱好者提供参考。

学习更多vb.net知识，请参看 vb.net 教程 目录