从画布保存的图像无法正确渲染
作者:互联网
我正在尝试使用以下代码将myCanvas的内容另存为图库中的图像文件(对于Windows Phone 8.1,不是Silverlight).当我运行该应用程序时,图像会保存但会变形.我究竟做错了什么?我已经上传了结果图像和预期结果.
public async void SaveFileToPhone()
{
var file = await KnownFolders.PicturesLibrary.CreateFileAsync("bug.png", CreationCollisionOption.GenerateUniqueName);
await SaveVisualElementToFile(myCanvas, file);
}
async Task SaveVisualElementToFile(FrameworkElement element, StorageFile file)
{
var renderTargetBitmap = new RenderTargetBitmap();
await renderTargetBitmap.RenderAsync(element, (int)element.Width, (int)element.Height);
var pixels = await renderTargetBitmap.GetPixelsAsync();
txt_bug.Text = "Width: " + (int)element.Width + " Height:" + (int)element.Height;
using (IRandomAccessStream stream = await file.OpenAsync(FileAccessMode.ReadWrite))
{
var encoder = await
BitmapEncoder.CreateAsync(BitmapEncoder.PngEncoderId, stream);
byte[] bytes = pixels.ToArray();
encoder.SetPixelData(BitmapPixelFormat.Bgra8,
BitmapAlphaMode.Ignore,
(uint)element.Width, (uint)element.Height,
96, 96, bytes);
await encoder.FlushAsync();
}
}
画布的XAML代码如下:
<Canvas x:Name="myCanvas" Background="#FF33FFE3" Margin="25,75,26,10"
ManipulationStarted="myCanvas_ManipulationStarted"
ManipulationCompleted="myCanvas_ManipulationCompleted"
ManipulationDelta="myCanvas_ManipulationDelta" ManipulationMode="All"
Tapped="myCanvas_Tapped" MinHeight="555" MinWidth="350" Width="350" Height="555">
<Canvas.Clip>
<RectangleGeometry Rect="0 0 350 555"/>
</Canvas.Clip>
</Canvas>
解决方法:
SetPixelData方法的参数不正确.
encoder.SetPixelData(BitmapPixelFormat.Bgra8,
BitmapAlphaMode.Ignore,
(uint)element.Width, (uint)element.Height,
96, 96, bytes);
将它们更改为以下内容可以使其正常工作.
encoder.SetPixelData(BitmapPixelFormat.Bgra8,
BitmapAlphaMode.Ignore,
(uint)renderTargetBitmap.PixelWidth,
(uint)renderTargetBitmap.PixelHeight,
DisplayInformation.GetForCurrentView().LogicalDpi,
DisplayInformation.GetForCurrentView().LogicalDpi,
bytes);
您可以从MSDN下载XAML render to bitmap sample以供参考.
标签:windows-rt,image,canvas,windows-phone-8-1,c 来源: https://codeday.me/bug/20191120/2044433.html