在实际的项目开发中，经常需要将信息保存成图片的形式，如屏幕截图、地图快照等操作，我中最近一个项目中便有这样的需求，项目（WPF）中用到GMap.NET控件，中地图上展示一些信息，过程中可能用户需要将地图信息保存下来，也就是地图快照，我的界面如下所示：
网上查了GMap相关的资料，没有找到GMap怎么截图的方法，最后找到网友提供的方法：将WPF控件转换成图片。
具体实现如下：
namespace QACDR2.Common
{
internal enum ImageType
{
Bmp,
Gif,
Jpeg,
Png,
Tiff,
Wdp
}
///
/// 控件到图片的转换
///
static class ControlToImageConverter
{
#region 私有方法
///
/// Convert any control to a PngBitmapEncoder
///
/// The control to convert to an ImageSource
/// The image type will indicate the type of return bitmap encoder
/// The returned ImageSource of the controlToConvert
private static BitmapEncoder GetImageFromControl(FrameworkElement controlToConvert, ImageType imageType)
{
var bounds = controlToConvert.GetBounds(controlToConvert.Parent as Visual);
var renderBitmap = new RenderTargetBitmap((Int32)bounds.Width, (Int32)bounds.Height, 96d,
96d, PixelFormats.Pbgra32);
renderBitmap.Render(controlToConvert);
BitmapEncoder encoder = GetBitmapEncoderByImageType(imageType);
// puch rendered bitmap into it
encoder.Frames.Add(BitmapFrame.Create(renderBitmap));
return encoder;
}
private static Rect GetBounds(this FrameworkElement element, Visual from)
{
Rect rect = Rect.Empty;
try
{
GeneralTransform transform = element.TransformToVisual(from);
rect = transform.TransformBounds(new Rect(0, 0, element.ActualWidth, element.ActualHeight));
// ReSharper disable EmptyGeneralCatchClause
}
catch
// ReSharper restore EmptyGeneralCatchClause
{
}
return rect;
}
///
/// Get an encoder by a specify image type
///
/// the image type
/// return an eccoder
private static BitmapEncoder GetBitmapEncoderByImageType(ImageType type)
{
switch (type)
{
case ImageType.Bmp:
return new BmpBitmapEncoder();
case ImageType.Gif:
return new GifBitmapEncoder();
case ImageType.Jpeg:
return new JpegBitmapEncoder();
case ImageType.Png:
return new PngBitmapEncoder();
case ImageType.Tiff:
return new TiffBitmapEncoder();
case ImageType.Wdp:
return new WmpBitmapEncoder();
default:
return new PngBitmapEncoder();
}
}
///
/// Get the iamge type by image file name
///
/// the file name of an image
/// the iamge type
private static ImageType GetImageTypeByFileName(string fileName)
{
ImageType returnType = ImageType.Png;
var extension = Path.GetExtension(fileName);
if (!String.IsNullOrEmpty(extension))
{
switch (extension.ToLower())
{
case ".bmp":
returnType = ImageType.Bmp;
break;
case ".gif":
returnType = ImageType.Gif;
break;
case ".jpeg":
case ".jpg":
case ".jpe":
case "jfif":
returnType = ImageType.Jpeg;
break;
case ".png":
returnType = ImageType.Png;
break;
case ".tiff":
case ".tif":
returnType = ImageType.Tiff;
break;
case ".wdp":
returnType = ImageType.Wdp;
break;
default:
returnType = ImageType.Png;
break;
}
}
return returnType;
}
#endregion
#region 提供的方法
///
/// Get an ImageSource of a control
///
/// The control to convert to an ImageSource
/// the image type
/// The returned ImageSource of the controlToConvert
public static BitmapSource GetImageOfControl(FrameworkElement controlToConvert, ImageType imageType)
{
// return first frame of image
var encoder = GetImageFromControl(controlToConvert, imageType);
if (encoder != null && encoder.Frames != null && encoder.Frames.Count > 0)
{
return encoder.Frames[0];
}
return new BitmapImage();
}
///
/// Get an ImageSource of a control(Jpeg as default type)
///
/// The control to convert to an ImageSource
/// The returned ImageSource of the controlToConvert
public static BitmapSource GetImageOfControl(FrameworkElement controlToConvert)
{
return GetImageOfControl(controlToConvert, ImageType.Jpeg);
}
///
/// Save an image of a control
///
/// The control to convert to an ImageSource
/// The location to save the image to
/// The returned ImageSource of the controlToConvert
public static Boolean SaveImageOfControl(FrameworkElement controlToConvert, String fileName)
{
try
{
var imageType = GetImageTypeByFileName(fileName);
using (var outStream = new FileStream(fileName, FileMode.Create))
{
var encoder = GetImageFromControl(controlToConvert, imageType);
encoder.Save(outStream);
}
}
catch (Exception e)
{
Console.WriteLine("Exception caught saving stream: {0}", e.Message);
return false;
}
return true;
}
public static BitmapImage ToBitmapImage(this BitmapSource bitmapSource)
{
var encoder = new JpegBitmapEncoder();
var memoryStream = new MemoryStream();
encoder.Frames.Add(BitmapFrame.Create(bitmapSource));
encoder.Save(memoryStream);
var bmp = new BitmapImage();
bmp.BeginInit();
bmp.StreamSource = new MemoryStream(memoryStream.ToArray());
bmp.EndInit();
memoryStream.Flush();
memoryStream.Close();
return bmp;
}
#endregion
}
}
GMap截图的效果图如下：
完美解决。