c# - 使用 SizeMode ZOOM 从 Picturebox 中选择颜色

Question

如何从 ZOOMed 图片框中获取点的颜色（鼠标光标的位置）？

我当前的代码不起作用

Private Sub pickColor(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles picBox.MouseClick
    Dim TempBitmap As New Bitmap(picBox.Image)
    Dim MyColor As Color
    MyColor = TempBitmap.GetPixel(e.X, e.Y)
End Sub

Answer 1

你可以尝试这样的事情：

Private Sub pickColor(ByVal sender As Object, ByVal e As MouseEventArgs) _
                      Handles picBox.MouseClick
  Using bmp As New Bitmap(picBox.ClientSize.Width, _
                          picBox.ClientSize.Height)
    picBox.DrawToBitmap(bmp, picBox.ClientRectangle)
    MessageBox.Show(bmp.GetPixel(e.X, e.Y).ToString())
  End Using
End Sub

Answer 2

我不知道有一种方法叫做DrawToBitmap. @LatsTech 比我的要好得多。我的解决方案只是简单地尝试将 Picturebox 的内容重新创建到 Bitmap 中。

 Private Sub PictureBox1_MouseClick(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseClick
    Dim bits As New Bitmap(PictureBox1.Width, PictureBox1.Height)
    Dim context As Graphics = Graphics.FromImage(bits)

    '' Create picturebox background
    context.FillRectangle(New SolidBrush(PictureBox1.BackColor), _
                          0, 0, bits.Width, bits.Height)

    '' Try to reproduce zoomed image thumbnail
    Dim ratio As Double = 1.0
    Dim imageWidth As Integer = PictureBox1.Image.Width
    Dim imageHeight As Integer = PictureBox1.Image.Height

    If imageWidth > bits.Width Then
        ratio = bits.Width / imageWidth

        imageWidth = bits.Width
        imageHeight *= ratio
    End If

    If imageHeight > bits.Height Then
        ratio = bits.Height / imageHeight

        imageHeight = bits.Height
        imageWidth *= ratio
    End If

    context.DrawImage(PictureBox1.Image, _
                      New Rectangle((bits.Width - imageWidth) / 2, _
                                    (bits.Height - imageHeight) / 2, _
                                    imageWidth, imageHeight), _
                      New Rectangle(0, 0, PictureBox1.Image.Width, _
                                    PictureBox1.Image.Height), _
                      GraphicsUnit.Pixel)

    MsgBox(bits.GetPixel(e.X, e.Y).ToString)
End Sub