Question

我想创建一个简单的VB实用程序来使用vb.net调整图像大小。我无法弄清楚用什么vb类来实际操作图像。 Image类和Bitmap类不起作用。

非常感谢任何想法，提示，技巧，教程链接。

感谢。

Answer 1

您只需使用此一行代码即可在visual basic .net

中调整图像大小

Public Shared Function ResizeImage(ByVal InputImage As Image) As Image
        Return New Bitmap(InputImage, New Size(64, 64))
End Function

其中;

＆＃34; inputImage的＆＃34;是要调整大小的图像。
＆＃34; 64 X 64＆＃34;是你需要改变它所需的尺寸，即32X32等。

Answer 2

Here is an article详细了解如何执行此操作。

Private Sub btnScale_Click(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles btnScale.Click
    ' Get the scale factor.
    Dim scale_factor As Single = Single.Parse(txtScale.Text)

    ' Get the source bitmap.
    Dim bm_source As New Bitmap(picSource.Image)

    ' Make a bitmap for the result.
    Dim bm_dest As New Bitmap( _
        CInt(bm_source.Width * scale_factor), _
        CInt(bm_source.Height * scale_factor))

    ' Make a Graphics object for the result Bitmap.
    Dim gr_dest As Graphics = Graphics.FromImage(bm_dest)

    ' Copy the source image into the destination bitmap.
    gr_dest.DrawImage(bm_source, 0, 0, _
        bm_dest.Width + 1, _
        bm_dest.Height + 1)

    ' Display the result.
    picDest.Image = bm_dest
End Sub

[编辑]
One more在类似的路线上。

Answer 3

这将使用最佳质量重新调整任何图像的大小，并支持带alpha的32bpp。新图像将原始图像置于新原始图像的原始宽高比内。

#Region " ResizeImage "
    Public Overloads Shared Function ResizeImage(SourceImage As Drawing.Image, TargetWidth As Int32, TargetHeight As Int32) As Drawing.Bitmap
        Dim bmSource = New Drawing.Bitmap(SourceImage)

        Return ResizeImage(bmSource, TargetWidth, TargetHeight)
    End Function

    Public Overloads Shared Function ResizeImage(bmSource As Drawing.Bitmap, TargetWidth As Int32, TargetHeight As Int32) As Drawing.Bitmap
        Dim bmDest As New Drawing.Bitmap(TargetWidth, TargetHeight, Drawing.Imaging.PixelFormat.Format32bppArgb)

        Dim nSourceAspectRatio = bmSource.Width / bmSource.Height
        Dim nDestAspectRatio = bmDest.Width / bmDest.Height

        Dim NewX = 0
        Dim NewY = 0
        Dim NewWidth = bmDest.Width
        Dim NewHeight = bmDest.Height

        If nDestAspectRatio = nSourceAspectRatio Then
            'same ratio
        ElseIf nDestAspectRatio > nSourceAspectRatio Then
            'Source is taller
            NewWidth = Convert.ToInt32(Math.Floor(nSourceAspectRatio * NewHeight))
            NewX = Convert.ToInt32(Math.Floor((bmDest.Width - NewWidth) / 2))
        Else
            'Source is wider
            NewHeight = Convert.ToInt32(Math.Floor((1 / nSourceAspectRatio) * NewWidth))
            NewY = Convert.ToInt32(Math.Floor((bmDest.Height - NewHeight) / 2))
        End If

        Using grDest = Drawing.Graphics.FromImage(bmDest)
            With grDest
                .CompositingQuality = Drawing.Drawing2D.CompositingQuality.HighQuality
                .InterpolationMode = Drawing.Drawing2D.InterpolationMode.HighQualityBicubic
                .PixelOffsetMode = Drawing.Drawing2D.PixelOffsetMode.HighQuality
                .SmoothingMode = Drawing.Drawing2D.SmoothingMode.AntiAlias
                .CompositingMode = Drawing.Drawing2D.CompositingMode.SourceOver

                .DrawImage(bmSource, NewX, NewY, NewWidth, NewHeight)
            End With
        End Using

        Return bmDest
    End Function
#End Region

Answer 4

不知道VB.NET的语法，但这里和想法

Dim source As New Bitmap("C:\image.png") 
Dim target As New Bitmap(size.Width, size.Height, PixelFormat.Format24bppRgb)

Using graphics As Graphics = Graphics.FromImage(target)
    graphics.DrawImage(source, new Size(48, 48)) 
End Using

Answer 5

    Dim x As Integer = 0
    Dim y As Integer = 0
    Dim k = 0
    Dim l = 0
    Dim bm As New Bitmap(p1.Image)
    Dim om As New Bitmap(p1.Image.Width, p1.Image.Height)
    Dim r, g, b As Byte
    Do While x < bm.Width - 1
        y = 0
        l = 0
        Do While y < bm.Height - 1
            r = 255 - bm.GetPixel(x, y).R
            g = 255 - bm.GetPixel(x, y).G
            b = 255 - bm.GetPixel(x, y).B
            om.SetPixel(k, l, Color.FromArgb(r, g, b))
            y += 3
            l += 1
        Loop
        x += 3
        k += 1
    Loop
    p2.Image = om

Answer 6

除了两个差异外，这基本上是Muhammad Saqib's answer：

1：添加宽度和高度功能参数。

2：这是一个细微差别，可以忽略...说“作为位图” ，而不是“作为图像”。 “按图像显示”确实可以正常工作。我只喜欢匹配Return类型。参见Image VS Bitmap Class.

Public Shared Function ResizeImage(ByVal InputBitmap As Bitmap, width As Integer, height As Integer) As Bitmap
    Return New Bitmap(InputImage, New Size(width, height))
End Function

例如。

Dim someimage As New Bitmap("C:\somefile")
someimage = ResizeImage(someimage,800,600)

在VB.NET中调整图像大小

6 个答案: