Question

我正在使用WinRT应用程序，出于某种原因，我想使用FileSavePicker将XAML树保存为图像。目前我正在将图像保存在ApplicationData中，这对于之后的浏览非常繁忙。我想要的是，用户选择自己选择的目录和名称并保存图像。我现在正在使用以下代码：

RenderTargetBitmap renderTargetBitmap = new RenderTargetBitmap();
        await renderTargetBitmap.RenderAsync(MainGrid);
        var file = await ApplicationData.Current.LocalFolder.CreateFileAsync("Image.png", creationCollisionOption.ReplaceExisting);
        var pixelBuffer = await renderTargetBitmap.GetPixelsAsync();

        using (var stream = await file.OpenAsync(FileAccessMode.ReadWrite))
        {
            var encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.PngEncoderId, stream);
            encoder.SetPixelData(
                BitmapPixelFormat.Bgra8,
                BitmapAlphaMode.Ignore,
                (uint)renderTargetBitmap.PixelWidth,
                (uint)renderTargetBitmap.PixelHeight, 96d, 96d,
                pixelBuffer.ToArray());

            await encoder.FlushAsync();
        }

Answer 1

像这样更改你的代码

RenderTargetBitmap renderTargetBitmap = new RenderTargetBitmap();
await renderTargetBitmap.RenderAsync(MainGrid);
var file = await DestinationFileFromUserAsync();
if (file != null)
{
    var pixelBuffer = await renderTargetBitmap.GetPixelsAsync();

    using (var stream = await file.OpenAsync(FileAccessMode.ReadWrite))
    {
        var encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.PngEncoderId, stream);
        encoder.SetPixelData(
            BitmapPixelFormat.Bgra8,
            BitmapAlphaMode.Ignore,
            (uint)renderTargetBitmap.PixelWidth,
            (uint)renderTargetBitmap.PixelHeight, 96d, 96d,
            pixelBuffer.ToArray());

        await encoder.FlushAsync();
    } 
}

private async Task<StorageFile> DestinationFileFromUserAsync()
{
    if (EnsureUnsnapped())
    {
        StorageFile file = null;
        FileSavePicker savePicker = new FileSavePicker();
        savePicker.SuggestedStartLocation = PickerLocationId.PicturesLibrary;
        savePicker.FileTypeChoices.Add("Images", new List<string>() { ".jpg", ".jpeg", ".png"});
        savePicker.SuggestedFileName = "New Image";

        file = await savePicker.PickSaveFileAsync();
        return file;
    }
    else
    {
        return null;
    }
}

internal bool EnsureUnsnapped()
{
    // FilePicker APIs will not work if the application is in a snapped state.
    // If an app wants to show a FilePicker while snapped, it must attempt to unsnap first
    return ((ApplicationView.Value != ApplicationViewState.Snapped) || ApplicationView.TryUnsnap());
}

不要忘记查看FileSavePicker class on MSDN

将XAML树渲染为图像并使用FileSavePicker进行保存

1 个答案: