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我已经在我当前的应用程序中编写了数百行图像管理代码，所有这些代码似乎都运行良好......除了上传的 GIF 的动画在某处松散。我已经将问题追溯到将图像保存到磁盘（以便缓存它们）的位置，因为它们直接从数据库（它们存储为 blob）显示它们看起来很好。

这是代码——我没有列出一堆对自定义对象和函数的调用，但我认为它们与问题无关——我认为它在这两个关键函数中的某个地方：

Private Sub CreateImageFileInCache()
    Dim CMSImage As Cms.DataTransferObjects.Image = My.Application.ManagerFactory.ImageManagerInstance.ById(ImageId)
    If CMSImage IsNot Nothing Then
        SaveMetaInfo(CMSImage)

        Using ms As New IO.MemoryStream(CMSImage.Data)
            Dim expectedSize As New Drawing.Size(Width, Height)
            Using img As System.Drawing.Image = resizeImage(System.Drawing.Bitmap.FromStream(ms), _
                                                            expectedSize, _
                                                            Drawing.Drawing2D.InterpolationMode.HighQualityBicubic, CMSImage.MimeType)
                img.Save(ImageCachePath, GetEncoderInfo(CMSImage.MimeType), GenerateEncodingParameters)
                img.Dispose()
            End Using
        End Using
    End If
End Sub


Private Function resizeImage(ByVal imgToResize As System.Drawing.Image, ByVal size As System.Drawing.Size, ByVal Quality As System.Drawing.Drawing2D.InterpolationMode, ByVal format As String) As System.Drawing.Bitmap
    Dim sourceWidth As Integer = imgToResize.Width
    Dim sourceHeight As Integer = imgToResize.Height
    Dim resizedImage As System.Drawing.Bitmap
    Dim canvas As System.Drawing.Graphics
    Dim calculatedSize As Drawing.Size = Global.Concrete.Base.Web.Controls.ProductImage.calculateNewImageSize(sourceWidth, sourceHeight, size)

    If calculatedSize.Width > imgToResize.Width AndAlso calculatedSize.Height > imgToResize.Height Then
        calculatedSize.Width = imgToResize.Width
        calculatedSize.Height = imgToResize.Height
    End If

    resizedImage = New System.Drawing.Bitmap(calculatedSize.Width, calculatedSize.Height)
    canvas = System.Drawing.Graphics.FromImage(resizedImage)
    canvas.InterpolationMode = Quality

    If Quality = Drawing.Drawing2D.InterpolationMode.HighQualityBicubic Then
        canvas.CompositingQuality = Drawing.Drawing2D.CompositingQuality.AssumeLinear
        canvas.SmoothingMode = Drawing.Drawing2D.SmoothingMode.AntiAlias
    End If
    canvas.DrawImage(imgToResize, 0, 0, calculatedSize.Width, calculatedSize.Height)
    canvas.Dispose()
    imgToResize.Dispose()

    If format.Contains("gif") Then
        Dim quantizer As Concrete.Cms.ImageManipulation.OctreeQuantizer
        quantizer = New Concrete.Cms.ImageManipulation.OctreeQuantizer(255, 8)
        resizedImage = quantizer.Quantize(resizedImage)
    End If

    Return resizedImage
End Function

任何建议都非常感激。

编辑：将 img.Save(ImageCachePath, GetFormat(MimeType)) 替换为对 .Save 的三参数调用仍然会产生静态 gif。

编辑 2：实际上对 GIF 几乎做任何事情似乎都会阻止它的动画！尝试使用 Canvas 调整它的大小，并尝试使用 Quantizing 来保持质量似乎都搞砸了动画。

干杯，马特

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1 回答 1

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好的，据我所知，这目前是不可能的。至少没有任何合理的努力。看起来确实可以通过在 WPF 上使用调整大小的方法来实现，但遗憾的是，WPF 是用于 winforms 而不是 ASP，并且渲染看起来像是一场噩梦 - 有可能通过使用 Ajax 更新面板并刷新每一帧的内容来解决它加载时的动画。不，谢谢！

我发现你不能在不丢失动画信息的情况下完全弄乱动画图像，特别是在如此成熟的技术中！

于 2010-11-03T16:33:21.580 回答