WPF：截取屏幕截图的方式
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原文地址: http://stackoverflow.com/questions/20338960/
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WPF: Way to take screenshots
提问by Tsukasa
Looking to modify the following to take a screenshot off all monitors. I have tried adapting it but my images are blank. Writing it to test.png is for testing. The byte[]will be sent to the receiving app.
希望修改以下内容以从所有显示器上截取屏幕截图。我试过调整它，但我的图像是空白的。将其写入 test.png 是为了测试。在byte[]将被发送到接收应用程序。
public byte[] Take()
{
int screenWidth = Convert.ToInt32(SystemParameters.VirtualScreenWidth);
int screenHeight = Convert.ToInt32(SystemParameters.VirtualScreenHeight);
int screenLeft = Convert.ToInt32(SystemParameters.VirtualScreenLeft);
int screenTop = Convert.ToInt32(SystemParameters.VirtualScreenTop);
RenderTargetBitmap renderTarget = new RenderTargetBitmap(screenWidth, screenHeight, 96, 96, PixelFormats.Pbgra32);
VisualBrush sourceBrush = new VisualBrush();
DrawingVisual drawingVisual = new DrawingVisual();
DrawingContext drawingContext = drawingVisual.RenderOpen();
using (drawingContext)
{
drawingContext.PushTransform(new ScaleTransform(1, 1));
drawingContext.DrawRectangle(sourceBrush, null, new Rect(new Point(0, 0), new Point(screenWidth, screenHeight)));
}
renderTarget.Render(drawingVisual);
PngBitmapEncoder pngEncoder = new PngBitmapEncoder();
pngEncoder.Frames.Add(BitmapFrame.Create(renderTarget));
Byte[] _imageArray;
using (MemoryStream outputStream = new MemoryStream())
{
pngEncoder.Save(outputStream);
_imageArray = outputStream.ToArray();
}
using (FileStream stream = new FileStream(@"c:\test.png", FileMode.Create, FileAccess.ReadWrite))
{
using (BinaryWriter writer = new BinaryWriter(stream))
{
writer.Write(_imageArray);
}
}
return _imageArray;
}
回答by Mark Feldman
First you'll need to add references for the following namespaces:
首先，您需要为以下命名空间添加引用：
using System.Drawing;
using System.Drawing.Imaging;
using System.Windows.Forms;
Then enumerate your monitors to get the bounding rectangle for all display surfaces and pass that in to the Graphics.CopyFromScreen()method call:
然后枚举您的监视器以获取所有显示表面的边界矩形并将其传递给Graphics.CopyFromScreen()方法调用：
private static BitmapSource CopyScreen()
{
var left = Screen.AllScreens.Min(screen => screen.Bounds.X);
var top = Screen.AllScreens.Min(screen => screen.Bounds.Y);
var right = Screen.AllScreens.Max(screen => screen.Bounds.X + screen.Bounds.Width);
var bottom = Screen.AllScreens.Max(screen => screen.Bounds.Y + screen.Bounds.Height);
var width = right - left;
var height = bottom - top;
using (var screenBmp = new Bitmap(width, height, System.Drawing.Imaging.PixelFormat.Format32bppArgb))
{
using (var bmpGraphics = Graphics.FromImage(screenBmp))
{
bmpGraphics.CopyFromScreen(left, top, 0, 0, new System.Drawing.Size(width, height));
return Imaging.CreateBitmapSourceFromHBitmap(
screenBmp.GetHbitmap(),
IntPtr.Zero,
Int32Rect.Empty,
BitmapSizeOptions.FromEmptyOptions());
}
}
}
Bear in mind though that monitors often don't fit neatly into a single rectangle, particularly if they have different resolution etc, so you might be better snap-shotting the individual screens. Either way, the solution to your problem is to change the coordinates that you were passing in to the Graphics.CopyFromScreen()method call.
请记住，尽管显示器通常不能整齐地放入单个矩形中，特别是如果它们具有不同的分辨率等，因此您最好对各个屏幕进行快照。无论哪种方式，您的问题的解决方案是更改您传递给Graphics.CopyFromScreen()方法调用的坐标。
EDIT: see Demetris Leptos's comment below, the code I've posted in this answer should be calling DeleteObject on the bitmap returned by screenBmp.GetHbitmap()so as to avoid a memory leak, as specified in the MSDN documentation.
编辑：请参阅下面的 Demetris Leptos 评论，我在此答案中发布的代码应该在返回的位图上调用 DeleteObject screenBmp.GetHbitmap()，以避免内存泄漏，如 MSDN 文档中所述。
