在Windows 10中将InkCanvas笔划保存为png/jpg图像

本文关键字：png jpg 图像 保存 Windows 中将 InkCanvas | 更新日期: 2023-09-27 18:20:34

有没有办法在Windows 10（UWP应用程序）中将InkCanvas中的笔划保存为png/jpg图像？

在Windows 10中将InkCanvas笔划保存为png/jpg图像

我知道这是一篇旧帖子，但以下是我为其他可能需要它的人做这件事的方法。

如果您不想将InkCanvas保存为文件或GIF，请在内存中进行操作。实际上我有三个选择。请注意，对于其中的一些内容，您需要添加对Win2D.uwp的引用，可以在NuGet上搜索该名称。它由微软提供。

  1. 将InkCanvas转换为字节数组：

    private byte[] ConvertInkCanvasToByteArray()
{
    var canvasStrokes = cvsSignature.InkPresenter.StrokeContainer.GetStrokes();
    if (canvasStrokes.Count > 0)
    {
        var width = (int)cvsSignature.ActualWidth;
        var height = (int)cvsSignature.ActualHeight;
        var device = CanvasDevice.GetSharedDevice();
        var renderTarget = new CanvasRenderTarget(device, width,
            height, 96);
        using (var ds = renderTarget.CreateDrawingSession())
        {
            ds.Clear(Windows.UI.Colors.White);
            ds.DrawInk(cvsSignature.InkPresenter.StrokeContainer.GetStrokes());
        }
        return renderTarget.GetPixelBytes();
    }
    else
    {
        return null;
    }
}

  2. 若您只需要一个像素的字节数组，那个么您就完成了。然而，如果你现在想生成一个图像，你可以使用WriteableBitmap来完成。

    private WriteableBitmap GetSignatureBitmapFull()
{
    var bytes = ConvertInkCanvasToByteArray();
    if (bytes != null)
    {
        var width = (int)cvsSignature.ActualWidth;
        var height = (int)cvsSignature.ActualHeight;
        var bmp = new WriteableBitmap(width, height);
        using (var stream = bmp.PixelBuffer.AsStream())
        {
            stream.Write(bytes, 0, bytes.Length);
            return bmp;
        }
    }
    else
        return null;
}
private async Task<WriteableBitmap> GetSignatureBitmapFullAsync()
{
    var bytes = ConvertInkCanvasToByteArray();
    if (bytes != null)
    {
        var width = (int)cvsSignature.ActualWidth;
        var height = (int)cvsSignature.ActualHeight;
        var bmp = new WriteableBitmap(width, height);
        using (var stream = bmp.PixelBuffer.AsStream())
        {
            await stream.WriteAsync(bytes, 0, bytes.Length);
            return bmp;
        }
    }
    else
        return null;
}

  3. 最后，这里有一个异步方法，如果你想在位图上进行裁剪，我可以使用它。这个方法的关键是要注意，使用这个方法，您不必首先将像素字节作为数组。您只需从画布中获取笔划，然后将其直接保存到内存流中

    private async Task<WriteableBitmap> GetSignatureBitmapCropped()
{
    try
    {
        var canvasStrokes = cvsSignature.InkPresenter.StrokeContainer.GetStrokes();
        if (canvasStrokes.Count > 0)
        {
            var bounds = cvsSignature.InkPresenter.StrokeContainer.BoundingRect;
            var xOffset = (uint)Math.Round(bounds.X);
            var yOffset = (uint)Math.Round(bounds.Y);
            var pixelWidth = (int)Math.Round(bounds.Width);
            var pixelHeight = (int)Math.Round(bounds.Height);
            using (var memStream = new InMemoryRandomAccessStream())
            {
                await cvsSignature.InkPresenter.StrokeContainer.SaveAsync(memStream);
                var decoder = await BitmapDecoder.CreateAsync(memStream);
                var transform = new BitmapTransform();
                var newBounds = new BitmapBounds();
                newBounds.X = 0;
                newBounds.Y = 0;
                newBounds.Width = (uint)pixelWidth;
                newBounds.Height = (uint)pixelHeight;
                transform.Bounds = newBounds;
                var pdp = await decoder.GetPixelDataAsync(
                    BitmapPixelFormat.Bgra8,
                    BitmapAlphaMode.Straight,
                    transform,
                    ExifOrientationMode.IgnoreExifOrientation,
                    ColorManagementMode.DoNotColorManage);
                var pixels = pdp.DetachPixelData();
                var cropBmp = new WriteableBitmap(pixelWidth, pixelHeight);
                using (var stream = cropBmp.PixelBuffer.AsStream())
                {
                    await stream.WriteAsync(pixels, 0, pixels.Length);
                }
                return cropBmp;
            }
        }
        else
        {
            return null;
        }
    }
    catch (Exception ex)
    {
        return null;
    }
}

希望这有助于在Windows 10 Universal中使用InkCanvas时提供一些替代方案。

当然，只需将笔划容器保存到流中并将其写入文件即可。

if (inkCanvas.InkPresenter.StrokeContainer.GetStrokes().Count > 0)
{
    var savePicker = new Windows.Storage.Pickers.FileSavePicker();
    savePicker.SuggestedStartLocation = Windows.Storage.Pickers.PickerLocationId.PicturesLibrary;
    savePicker.FileTypeChoices.Add("PNG", new System.Collections.Generic.List<string> { ".png" });
    Windows.Storage.StorageFile file = await savePicker.PickSaveFileAsync();
    if (null != file)
    {
        try
        {
            using (IRandomAccessStream stream = await file.OpenAsync(FileAccessMode.ReadWrite))
            {
                await inkCanvas.InkPresenter.StrokeContainer.SaveAsync(stream);
            }
        }
        catch (Exception ex)
        {
        }
    }
}

更多InkCanvas示例可以在此处找到。

您想要的是拍摄屏幕快照。在这种情况下，RenderTargetBitmap似乎会有所帮助。它可以将任意UIElement渲染为位图。你可以参考我在这篇文章中的回复。

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