使用不同的DPI捕获控件的屏幕截图 [英] Capture screenshot of control with different DPI

问题描述

我可以捕获正常100％DPI的控件截图。但是当DPI变为125％时，屏幕截图不正确。

I can capture screenshot of control for normal 100% DPI. But when the DPI changed to 125% then the screenshot is not proper.

// Get absolute location on screen of upper left corner of button
System.Windows.Point locationFromScreen = this.sv.PointToScreen(new System.Windows.Point(0, 0));

// Transform screen point to WPF device independent point
PresentationSource source = PresentationSource.FromVisual(this);

System.Windows.Point targetPoints = source.CompositionTarget.TransformFromDevice.Transform(locationFromScreen);

var bmpScreenshot = new Bitmap((int)sv.ActualWidth,
                               (int)sv.ActualHeight,
                               System.Drawing.Imaging.PixelFormat.Format32bppArgb);

// Create a graphics object from the bitmap.
var gfxScreenshot = Graphics.FromImage(bmpScreenshot);

		   gfxScreenshot.CopyFromScreen((int)targetPoints.X,
                                       (int)targetPoints.Y,
                                       0,
                                       0,
                                      new System.Drawing.Size((int)sv.ActualWidth, (int)sv.ActualHeight),
                                       CopyPixelOperation.SourceCopy);

            
byte[] data;
using (var stream = new System.IO.MemoryStream())
{
  bmpScreenshot.Save(stream, System.Drawing.Imaging.ImageFormat.Bmp);
  data = stream.ToArray();
}
            var result = Convert.ToBase64String(data);
            winObj = new Window1();

            MemoryStream ms = new MemoryStream();
            ((System.Drawing.Bitmap)bmpScreenshot).Save(ms, System.Drawing.Imaging.ImageFormat.Bmp);
            BitmapImage image = new BitmapImage();
            image.BeginInit();
            ms.Seek(0, SeekOrigin.Begin);
            image.StreamSource = ms;
            image.EndInit();

            winObj.imageViewer.Source = image;
            winObj.ShowDialog();
            bmpScreenshot.Dispose();

请提示方法，以便可以使用任何DPI捕获屏幕截图。

Please suggest approach so that the screenshot can be captured with any DPI.

推荐答案

嗨    Vipul_Langalia，



>>请提示方法以便截图即可使用任何DPI捕获



您可以尝试以下方法：使用RenderTargetBitmap类和PngBitmapEncoder 

Hi   Vipul_Langalia,

>>Please suggest approach so that the screenshot can be captured with any DPI

You can try the following method : use RenderTargetBitmap class and PngBitmapEncoder 

        SaveControlImage(sv);


       // Save a control's image.
        private void SaveControlImage(FrameworkElement control )
        {
            // Get the size of the Visual and its descendants.
            Rect rect = VisualTreeHelper.GetDescendantBounds(control);

            // Make a DrawingVisual to make a screen
            // representation of the control.
            DrawingVisual dv = new DrawingVisual();

            using (DrawingContext ctx = dv.RenderOpen())
            {
                VisualBrush brush = new VisualBrush(control);
                ctx.DrawRectangle(brush, null, new Rect(rect.Size));
            }

            // Make a bitmap and draw on it.
            int width = (int)control.ActualWidth;
            int height = (int)control.ActualHeight;
            RenderTargetBitmap rtb = new RenderTargetBitmap(
                width, height, 96, 96, PixelFormats.Pbgra32);
            rtb.Render(dv);

            // Make a PNG encoder.
            PngBitmapEncoder encoder = new PngBitmapEncoder();
            encoder.Frames.Add(BitmapFrame.Create(rtb));

            MemoryStream stream = new MemoryStream();
            encoder.Save(stream);

            BitmapImage image = new BitmapImage();
            image.BeginInit();
            stream.Seek(0, SeekOrigin.Begin);
            image.StreamSource = stream;
            image.EndInit();

            imageViewerforms winObj = new imageViewerforms();

            winObj.imageViewer.Source = image;
            winObj.ShowDialog();
        }

最好的问候，



Yong Lu

Best Regards,

Yong Lu

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