Question

我正在使用一组图形叠加来使用图形对象在图片框控件内绘制图像。我已将Picturebox放在Panel中，并将Panel设置为自动滚动。我现在需要知道的是使用鼠标滚轮以小幅度增大图片的大小，同时保持绘制图像的质量。有谁知道怎么做？

当我使用下面的Abdias软件代码更新时，当picturebox的Sizemode属性设置为StretchImage时，图片开始变小。我有鼠标的平移功能可能会干扰保持此代码无法正常工作。有任何想法吗？有什么可以阻止它正常工作？

的解决 的

这个代码对我来说比下面的任何一个代码都好得多：

Private Sub PictureBox_MouseWheel(sender As System.Object,
                             e As MouseEventArgs) Handles PictureBox1.MouseWheel
    If e.Delta <> 0 Then
        If e.Delta <= 0 Then
            If PictureBox1.Width < 500 Then Exit Sub 'minimum 500?
        Else
            If PictureBox1.Width > 2000 Then Exit Sub 'maximum 2000?
        End If

        PictureBox1.Width += CInt(PictureBox1.Width * e.Delta / 1000)
        PictureBox1.Height += CInt(PictureBox1.Height * e.Delta / 1000)
    End If

End Sub

Answer 1

您可以尝试使用此代码。它假定表单上存在Panel1和PictureBox1 PictureBox1 Panel1 Panel1.AutoScroll = True PictureBox，Public Class Form1 Private _originalSize As Size = Nothing Private _scale As Single = 1 Private _scaleDelta As Single = 0.0005 Private Sub Form_MouseWheel(sender As System.Object, e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseWheel 'if very sensitive mouse, change 0.00005 to something even smaller _scaleDelta = Math.Sqrt(PictureBox1.Width * PictureBox1.Height) * 0.00005 If e.Delta < 0 Then _scale -= _scaleDelta ElseIf e.Delta > 0 Then _scale += _scaleDelta End If If e.Delta <> 0 Then _ PictureBox1.Size = New Size(CInt(Math.Round(_originalSize.Width * _scale)), _ CInt(Math.Round(_originalSize.Height * _scale))) End Sub Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load PictureBox1.SizeMode = PictureBoxSizeMode.StretchImage 'init this from here or a method depending on your needs If PictureBox1.Image IsNot Nothing Then PictureBox1.Size = Panel1.Size _originalSize = Panel1.Size End If End Sub End Class上有图像集

代码不会计算缩放的中心点，但您可以使用e.Location（或e.X / e.Y）。

更新 - 这里的新代码（应该）比之前更强大（见下）：

Public Class Form1

    Private _scale As New SizeF(1, 1)
    Private _scaleDelta As New SizeF(0.01, 0.01) '1% for each wheel tick

    Private Sub Form_MouseWheel(sender As System.Object, 
                                e As MouseEventArgs) Handles Me.MouseWheel
'count incrementally 
        _scale.Height = 1
        _scale.Width = 1

        If e.Delta < 0 Then
            _scale += _scaleDelta
        ElseIf e.Delta > 0 Then
            _scale -= _scaleDelta
        End If

        If e.Delta <> 0 Then _
        PictureBox1.Scale(_scale)

    End Sub

    Private Sub Form1_Load(sender As System.Object, 
                           e As EventArgs) Handles MyBase.Load

        PictureBox1.SizeMode = PictureBoxSizeMode.StretchImage

        'init picturebox size = image size
        If PictureBox1.Image IsNot Nothing Then
            PictureBox1.Scale(New SizeF(1, 1))
            PictureBox1.Size = PictureBox1.Image.Size
        End If

    End Sub

End Class

旧代码 - 有效，但在大型更改时不稳定，可能是由于Scale（）中的舍入错误：

{{1}}

Answer 2

基本上，你需要一个图像查看器。我之前用过这个： http://cyotek.com/blog/creating-a-scrollable-and-zoomable-image-viewer-in-csharp-part-4

效果很好。但是，它是一个用户控件。

对于picturebox，您需要从图像创建图形，然后插值。这是一个例子： http://www.dotnetcurry.com/ShowArticle.aspx?ID=196

我没有检查过这个，但看起来会起作用。

Answer 3

我注意到StretchImage SizeMode忽略了图像比率会产生不良影响。我刚刚添加了一个宽度和高度比变量，以包含在＆＃34; zoom＆＃34;算法。请参阅下面的代码中的_ratWidth和_ratHeight。

Public Class Form1

Private _originalSize As Size = Nothing
Private _scale As Single = 1
Private _scaleDelta As Single = 0.0005
Private _ratWidth, _ratHeight As Double

Private Sub Form_MouseWheel(sender As System.Object, e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseWheel

    'if very sensitive mouse, change 0.00005 to something even smaller   
    _scaleDelta = Math.Sqrt(PictureBox1.Width * PictureBox1.Height) * 0.00005

    If e.Delta < 0 Then
        _scale -= _scaleDelta
    ElseIf e.Delta > 0 Then
        _scale += _scaleDelta
    End If

    If e.Delta <> 0 Then _
    PictureBox1.Size = New Size(CInt(Math.Round((_originalSize.Width * _ratWidth) * _scale)), _
                                CInt(Math.Round((_originalSize.Height * _ratHeight) * _scale)))

End Sub

Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
    PictureBox1.SizeMode = PictureBoxSizeMode.StretchImage

    'init this from here or a method depending on your needs
    If PictureBox1.Image IsNot Nothing Then
        _ratWidth = PictureBox1.Image.Width / PictureBox1.Image.Height
        _ratHeight = PirctureBox1.Image.Height / PictureBox1.Image.Width
        PictureBox1.Size = Panel1.Size
        _originalSize = Panel1.Size
    End If
End Sub
End Class

如何在vb.net中使用滚轮放大Picturebox

3 个答案: