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我有两个想要合并在一起的位图图像。我发现我可以用 writeablebitmap 做到这一点，但我如何首先将这些图像转换为 writeablebitmaps？

更新：我找不到将位图直接转换为可写位图的方法，所以我所做的是将位图写入隔离存储并在流对象中再次读取。之后，Xyroid 下面给出的代码可用于合并图像并将合并的图像转换为位图。

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2 回答 2

9

在这里，我给你合并两个图像的代码。WinRT 的 WriteableBitmap 不同，它的构造函数以高度和宽度作为参数。我已将WriteableBitmapEx用于某些功能。

XAML

<Grid Background="{StaticResource ApplicationPageBackgroundThemeBrush}">
    <Grid.ColumnDefinitions>
        <ColumnDefinition />
        <ColumnDefinition />
    </Grid.ColumnDefinitions>
    <Canvas x:Name="BaseCanvas" Width="683" Height="768">
        <Image Source="Assets/img1.png" />
        <Image Source="Assets/img2.png" Canvas.Top="308" />
    </Canvas>
    <Image x:Name="imgTarget" Grid.Column="1" Stretch="None"/>
</Grid>

C＃

protected async override void OnNavigatedTo(NavigationEventArgs e)
{
    StorageFile destiFile = await ApplicationData.Current.TemporaryFolder.CreateFileAsync("Merged.png", CreationCollisionOption.ReplaceExisting);

    WriteableBitmap wb;

    wb = await Render();

    using (IRandomAccessStream stream = await destiFile.OpenAsync(FileAccessMode.ReadWrite))
    {
        BitmapEncoder encoder = await BitmapEncoder.CreateAsync(
            BitmapEncoder.PngEncoderId, stream);
        Stream pixelStream = wb.PixelBuffer.AsStream();
        byte[] pixels = new byte[pixelStream.Length];
        await pixelStream.ReadAsync(pixels, 0, pixels.Length);

        encoder.SetPixelData(BitmapPixelFormat.Bgra8, BitmapAlphaMode.Ignore,
            (uint)wb.PixelWidth, (uint)wb.PixelHeight, 96.0, 96.0, pixels);
        await encoder.FlushAsync();
    }

    var bitmp = new BitmapImage();
    using (var strm = await destiFile.OpenReadAsync())
    {
        bitmp.SetSource(strm);
        imgTarget.Source = bitmp;
    }
}

private async Task<WriteableBitmap> Render()
{
    var Assets = await Windows.ApplicationModel.Package.Current.InstalledLocation.GetFolderAsync("Assets");

    StorageFile file1 = await Assets.GetFileAsync("img1.png");
    StorageFile file2 = await Assets.GetFileAsync("img2.png");

    BitmapImage i1 = new BitmapImage();
    BitmapImage i2 = new BitmapImage();

    using (IRandomAccessStream strm = await file1.OpenReadAsync())
    {
        i1.SetSource(strm);
    }

    using (IRandomAccessStream strm = await file2.OpenReadAsync())
    {
        i2.SetSource(strm);
    }

    WriteableBitmap img1 = new WriteableBitmap(i1.PixelWidth, i1.PixelHeight);
    WriteableBitmap img2 = new WriteableBitmap(i2.PixelWidth, i2.PixelHeight);
    using (IRandomAccessStream strm = await file1.OpenReadAsync())
    {
        img1.SetSource(strm);
    }

    using (IRandomAccessStream strm = await file2.OpenReadAsync())
    {
        img2.SetSource(strm);
    }


    WriteableBitmap destination = new WriteableBitmap((int)(img1.PixelWidth > img2.PixelWidth ? img1.PixelWidth : img2.PixelWidth), (int)(img1.PixelHeight + img1.PixelHeight));
    destination.Clear(Colors.White);
    destination.Blit(new Rect(0, 0, (int)img1.PixelWidth, (int)img1.PixelHeight),img1,new Rect(0, 0, (int)img1.PixelWidth, (int)img1.PixelHeight));
    destination.Blit(new Rect(0, (int)img1.PixelHeight, (int)img2.PixelWidth, (int)img2.PixelHeight), img2, new Rect(0, 0, (int)img2.PixelWidth, (int)img2.PixelHeight));
    return destination;
}

请注意，您必须添加System.Runtime.InteropServices.WindowsRuntime命名空间。

更新 1

假设如果你已经有两个BitmapImage img1and img2，那么就这样做

protected async override void OnNavigatedTo(NavigationEventArgs e)
{
    StorageFile destiFile = await ApplicationData.Current.TemporaryFolder.CreateFileAsync("Merged.png", CreationCollisionOption.ReplaceExisting);

    WriteableBitmap wb;

    wb = await Render();

    using (IRandomAccessStream stream = await destiFile.OpenAsync(FileAccessMode.ReadWrite))
    {
        BitmapEncoder encoder = await BitmapEncoder.CreateAsync(
            BitmapEncoder.PngEncoderId, stream);
        Stream pixelStream = wb.PixelBuffer.AsStream();
        byte[] pixels = new byte[pixelStream.Length];
        await pixelStream.ReadAsync(pixels, 0, pixels.Length);

        encoder.SetPixelData(BitmapPixelFormat.Bgra8, BitmapAlphaMode.Ignore,
            (uint)wb.PixelWidth, (uint)wb.PixelHeight, 96.0, 96.0, pixels);
        await encoder.FlushAsync();
    }

    var bitmp = new BitmapImage();
    using (var strm = await destiFile.OpenReadAsync())
    {
        bitmp.SetSource(strm);
        imgTarget.Source = bitmp;
    }
}

private async Task<WriteableBitmap> Render()
{  
    WriteableBitmap destination = new WriteableBitmap((int)(img1.PixelWidth > img2.PixelWidth ? img1.PixelWidth : img2.PixelWidth), (int)(img1.PixelHeight + img1.PixelHeight));
    destination.Clear(Colors.White);
    destination.Blit(new Rect(0, 0, (int)img1.PixelWidth, (int)img1.PixelHeight),img1,new Rect(0, 0, (int)img1.PixelWidth, (int)img1.PixelHeight));
    destination.Blit(new Rect(0, (int)img1.PixelHeight, (int)img2.PixelWidth, (int)img2.PixelHeight), img2, new Rect(0, 0, (int)img2.PixelWidth, (int)img2.PixelHeight));
    return destination;
}
于 2013-04-01T08:50:22.867 回答
0

我在 Silverlight 上做了很多工作，我相信商店应用程序在很多方面都相似。

考虑这个构造函数：

WriteableBitmap(BitmapSource)
- Initializes a new instance of the WriteableBitmap class using the
  provided BitmapSource.

下一个问题是，如何从图像中获取“BitmapSource”？你可以这样做：

(BitmapSource)MyImage.Source

虽然这假设源（类型为“ImageSource”）实际上是一个“BitmapSource”实例。也就是说，从 Silverlight 5.0 开始，Silverlight 中唯一从 ImageSource 派生的类是 BitmapSource，所以我怀疑这会是一个问题。

所以这样的事情可能会奏效：

WriteableBitmap((BitmapSource)MyImage.Source)

最后，这里有一个开源项目可能会有所帮助：http ://writeablebitmapex.codeplex.com/

于 2013-03-31T14:21:35.897 回答