通过其SVG副本生成的栅格图像中存在意外的视觉元素

如何解决通过其SVG副本生成的栅格图像中存在意外的视觉元素

使用SkiaSharp库从它们的SVG副本（作为嵌入式资源附加到应用程序）生成的PNG图像（如下图所示）的背景中存在意外的残渣数量在Button和ToolbarItem视图中。

粗略地看，我认为问题与从SVG生成PNG图像的方式有关，但是到目前为止，由于我无法隔离有问题的部分，因此无法隔离导致此“不正确转换”的部分在GetEquivalentBitmapImagePath()方法的实现中（如下所示）。

生成上述实体的代码：

string calculationHistoryIcon = GetEquivalentBitmapImagePath
                          (CALCULATION_HISTORY_ICON_RESOURCE_IDENTIFIER,80,80);
ToolbarItem calculationHistoryToolbarItem = new ToolbarItem()
                { IconImageSource = calculationHistoryIcon };
this.ToolbarItems.Add(calculationHistoryToolbarItem);

生成上述实体的代码：

string fullKeypadIcon = GetEquivalentBitmapImagePath
                        (FULL_KEYPAD_ICON_RESOURCE_IDENTIFIER,50,80);
Button keypadBtn = new Button()
{
    HorizontalOptions = LayoutOptions.Fill,VerticalOptions = LayoutOptions.Fill
};
keypadBtn.ImageSource = fullKeypadIcon;

以下方法用于生成PNG图像：

private string GetEquivalentBitmapImagePath
        (string embeddedVectorIdentifier,float widthOfBitmapImage,float heightOfBitmapImage)
{
    // For converting vector (.svg) images to raster images
    SKSvg svg;
    SKBitmap bitmap;
    SKCanvas canvas;
    SKImage image;
    SKData encodedData;
    Stream imageStream;

    string vectorImageFile;
    Stream embeddedResourceStream;
    FileStream vectorImageStream,bitmapImageStream;
    string bitmapImagePath;

    if (widthOfBitmapImage < 1)
        throw new ArgumentException("Invalid value passed","widthOfFinalImage");
    if (heightOfBitmapImage < 1)
        throw new ArgumentException("Invalid value passed","heightOfFinalImage");

    try
    {
        vectorImageFile = Path.Combine(FileSystem.CacheDirectory,embeddedVectorIdentifier);
        embeddedResourceStream = Assembly.GetExecutingAssembly().GetManifestResourceStream(embeddedVectorIdentifier);
        vectorImageStream = new FileStream(vectorImageFile,FileMode.Create,FileAccess.Write);
        embeddedResourceStream.CopyTo(vectorImageStream);
        embeddedResourceStream.Flush();
        vectorImageStream.Flush();
        embeddedResourceStream.Close();
        embeddedResourceStream.Dispose();
        vectorImageStream.Close();
        vectorImageStream.Dispose();

        svg = new SKSvg(new SKSize(widthOfBitmapImage,heightOfBitmapImage));
        svg.Load(vectorImageFile);
        bitmap = new SKBitmap(Convert.ToInt32(svg.CanvasSize.Width),Convert.ToInt32(svg.CanvasSize.Height));
        canvas = new SKCanvas(bitmap);

        canvas.DrawPicture(svg.Picture);
        canvas.Flush();
        canvas.Save();
        image = SKImage.FromBitmap(bitmap);
        encodedData = image.Encode(SKEncodedImageFormat.Png,100);
        bitmapImagePath = vectorImageFile.Replace(".svg",".png");
        bitmapImageStream = File.Open(bitmapImagePath,FileAccess.Write,FileShare.None);
        encodedData.SaveTo(bitmapImageStream);
        bitmapImageStream.Flush(true);
        bitmapImageStream.Dispose();
        File.Delete(vectorImageFile);
        return bitmapImagePath;
    }
    catch (Exception ex)
    {
        throw;
    }
}

谢谢。