基于C# wpf实现桌面放大镜
作者：CodeOfCC
做桌面截屏功能时需要放大镜,显示鼠标所在位置的放大图像,所以本文为大家介绍了如何基于C# wpf实现桌面放大镜功能,有需要的小伙伴可以参考下
前言
做桌面截屏功能时需要放大镜，显示鼠标所在位置的放大图像，在wpf中使用Bursh的ViewBox属性可以实现图像放大，桌面的画面则需要截屏了，总的来说还是比较容易实现的。
一、如何实现?
1、制作无边框窗口
推荐使用WindowChrome
<Window Background="{x:Null}" ResizeMode="NoResize" WindowStyle="None">WindowChrome放在Window 标签内
<WindowChrome.WindowChrome>
<WindowChrome GlassFrameThickness="-1" CaptionHeight="0" />
</WindowChrome.WindowChrome>2、Viewbox放大
定义一个Ellipse 控件作为放大镜，Viewbox默认为相对单位，即范围时0-1，值越小放大越大
<Ellipse Stroke="LightBlue">
<Ellipse.Fill>
<ImageBrush x:Name="ib" Viewbox="0,0,0.5,0.5" />
</Ellipse.Fill>
</Ellipse>3、截屏显示
（1）、截屏
参考《C# wpf 使用GDI+实现截屏》里的简单截屏即完成。获取的数据类型为Bitmap。
（2）、转BitmapSource
参考《C# wpf Bitmap转换成WriteableBitmap（BitmapSource）的方法》将Bitmap转换为转换成wpf对象。
（3）、显示
获取到BitmapSource给控件赋值即可。
//显示到界面 ib.ImageSource = wb;
4、定时截屏
显示桌面必然需要实时的画面，所以需要定时截屏。
//启动定时器，截屏
var dispatcherTimer = new DispatcherTimer() { Interval = TimeSpan.FromMilliseconds(33), };
dispatcherTimer.Tick += (s, e) =>
{
//截屏并显示
};
dispatcherTimer.Start();二、完整代码
完整代码依赖System.Drawing，添加引用方法可以参考《C# wpf 使用GDI+实现截屏》。
MainWindow.xaml
<Window x:Class="WpfMagnifier.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WpfMagnifier"
mc:Ignorable="d"
Background="{x:Null}"
ResizeMode="NoResize"
WindowStyle="None"
ShowInTaskbar="False"
Topmost="True"
Title="MainWindow" Height="200" Width="200"
MouseLeftButtonDown="Window_MouseDown">
<WindowChrome.WindowChrome>
<WindowChrome GlassFrameThickness="-1" CaptionHeight="0" />
</WindowChrome.WindowChrome>
<Ellipse Stroke="LightBlue">
<Ellipse.Fill>
<ImageBrush x:Name="ib" Viewbox="0,0,0.5,0.5" />
</Ellipse.Fill>
</Ellipse>
</Window>MainWindow.xaml.cs
using System;
using System.Windows;
using System.Windows.Input;
using System.Windows.Media.Imaging;
using System.Windows.Threading;
namespace WpfMagnifier
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
//启动定时器，截屏
var dispatcherTimer = new DispatcherTimer() { Interval = TimeSpan.FromMilliseconds(33), };
dispatcherTimer.Tick += (s, e) =>
{
//gdi+截屏，截取窗口左边的区域（可根据具体使用场景调整截屏位置）,使用PointToScreen消除dpi影响
var leftTop = PointToScreen(new Point(-Width, 0));
var rightBottom = PointToScreen(new Point(0, Height));
var bm = Snapshot((int)leftTop.X, (int)leftTop.Y, (int)(rightBottom.X - leftTop.X), (int)(rightBottom.Y - leftTop.Y));
var wb = BitmapToWriteableBitmap(bm);
//显示到界面
ib.ImageSource = wb;
};
dispatcherTimer.Start();
}
private void Window_MouseDown(object sender, MouseButtonEventArgs e)
{
DragMove();
}
/// <summary>
/// 截取一帧图片
/// </summary>
/// <param name="x">x坐标</param>
/// <param name="y">y坐标</param>
/// <param name="width">宽</param>
/// <param name="height">高</param>
/// <returns>截屏后的位图对象，需要调用Dispose手动释放资源。</returns>
public static System.Drawing.Bitmap Snapshot(int x, int y, int width, int height)
{
System.Drawing.Bitmap bitmap = new System.Drawing.Bitmap(width, height, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
using (System.Drawing.Graphics graphics = System.Drawing.Graphics.FromImage(bitmap))
{
graphics.CopyFromScreen(x, y, 0, 0, new System.Drawing.Size(width, height), System.Drawing.CopyPixelOperation.SourceCopy);
}
return bitmap;
}
//将Bitmap 转换成WriteableBitmap
public static WriteableBitmap BitmapToWriteableBitmap(System.Drawing.Bitmap src)
{
var wb = CreateCompatibleWriteableBitmap(src);
System.Drawing.Imaging.PixelFormat format = src.PixelFormat;
if (wb == null)
{
wb = new WriteableBitmap(src.Width, src.Height, 0, 0, System.Windows.Media.PixelFormats.Bgra32, null);
format = System.Drawing.Imaging.PixelFormat.Format32bppArgb;
}
BitmapCopyToWriteableBitmap(src, wb, new System.Drawing.Rectangle(0, 0, src.Width, src.Height), 0, 0, format);
return wb;
}
//创建尺寸和格式与Bitmap兼容的WriteableBitmap
public static WriteableBitmap CreateCompatibleWriteableBitmap(System.Drawing.Bitmap src)
{
System.Windows.Media.PixelFormat format;
switch (src.PixelFormat)
{
case System.Drawing.Imaging.PixelFormat.Format16bppRgb555:
format = System.Windows.Media.PixelFormats.Bgr555;
break;
case System.Drawing.Imaging.PixelFormat.Format16bppRgb565:
format = System.Windows.Media.PixelFormats.Bgr565;
break;
case System.Drawing.Imaging.PixelFormat.Format24bppRgb:
format = System.Windows.Media.PixelFormats.Bgr24;
break;
case System.Drawing.Imaging.PixelFormat.Format32bppRgb:
format = System.Windows.Media.PixelFormats.Bgr32;
break;
case System.Drawing.Imaging.PixelFormat.Format32bppPArgb:
format = System.Windows.Media.PixelFormats.Pbgra32;
break;
case System.Drawing.Imaging.PixelFormat.Format32bppArgb:
format = System.Windows.Media.PixelFormats.Bgra32;
break;
default:
return null;
}
return new WriteableBitmap(src.Width, src.Height, 0, 0, format, null);
}
//将Bitmap数据写入WriteableBitmap中
public static void BitmapCopyToWriteableBitmap(System.Drawing.Bitmap src, WriteableBitmap dst, System.Drawing.Rectangle srcRect, int destinationX, int destinationY, System.Drawing.Imaging.PixelFormat srcPixelFormat)
{
var data = src.LockBits(new System.Drawing.Rectangle(new System.Drawing.Point(0, 0), src.Size), System.Drawing.Imaging.ImageLockMode.ReadOnly, srcPixelFormat);
dst.WritePixels(new Int32Rect(srcRect.X, srcRect.Y, srcRect.Width, srcRect.Height), data.Scan0, data.Height * data.Stride, data.Stride, destinationX, destinationY);
src.UnlockBits(data);
}
}
}三、效果预览
显示的是窗口（放大镜）左边的画面
到此这篇关于基于C# wpf实现桌面放大镜的文章就介绍到这了,更多相关C# wpf放大镜内容请搜索脚本之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持脚本之家！