与众不同 windows phone (22) - Device（设备）之摄像头（硬件快门, 自动对焦, 实时修改捕获视频）...

原文:与众不同 windows phone (22) - Device（设备）之摄像头（硬件快门, 自动对焦, 实时修改捕获视频）

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与众不同 windows phone (22) - Device（设备）之摄像头（硬件快门, 自动对焦, 实时修改捕获视频）

作者：webabcd





介绍

与众不同 windows phone 7.5 (sdk 7.1) 之设备

• 硬件快门
• 自动对焦、自动对焦到指定的点
• 实时修改捕获到的视频帧

示例

1、演示如何响应硬件快门

HardwareShutter.xaml

<phone:PhoneApplicationPage x:Class="Demo.Device.Camera.HardwareShutter"xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"xmlns:d="http://schemas.microsoft.com/expression/blend/2008"xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"FontFamily="{StaticResource PhoneFontFamilyNormal}"FontSize="{StaticResource PhoneFontSizeNormal}"Foreground="{StaticResource PhoneForegroundBrush}"SupportedOrientations="Portrait" Orientation="Portrait"mc:Ignorable="d" d:DesignHeight="768" d:DesignWidth="480"shell:SystemTray.IsVisible="True"><Grid x:Name="LayoutRoot" Background="Transparent"><StackPanel Orientation="Vertical"><Canvas Width="480" Height="320"><Canvas.Background><VideoBrush x:Name="videoBrush"><VideoBrush.RelativeTransform><RotateTransform CenterX="0.5" CenterY="0.5" Angle="90" />VideoBrush.RelativeTransform>VideoBrush>Canvas.Background>Canvas><TextBlock Name="lblMsg" Text="通过按硬件快门来查看演示效果（半按压、全按压、释放）" TextWrapping="Wrap" />StackPanel>Grid>phone:PhoneApplicationPage>

HardwareShutter.xaml.cs

/** 演示如何捕获相机的硬件快门的相关事件* * CameraButtons.ShutterKeyHalfPressed - 硬件快门半按压时所触发的事件* CameraButtons.ShutterKeyPressed - 硬件快门全按压时所触发的事件* CameraButtons.ShutterKeyReleased - 硬件快门被释放时所触发的事件* * * 注：无论是拍照模式还是摄像模式，只有在摄像头工作起来的时候，系统才能响应硬件快门的相关事件*/using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using Microsoft.Phone.Controls;using Microsoft.Devices;
using System.Windows.Navigation;namespace Demo.Device.Camera
{public partial class HardwareShutter : PhoneApplicationPage{private PhotoCamera _camera;public HardwareShutter(){InitializeComponent();}protected override void OnNavigatedTo(NavigationEventArgs e){if (PhotoCamera.IsCameraTypeSupported(CameraType.Primary)){_camera = new PhotoCamera(CameraType.Primary);// 注册硬件快门的相关事件CameraButtons.ShutterKeyHalfPressed += CameraButtons_ShutterKeyHalfPressed;CameraButtons.ShutterKeyPressed += CameraButtons_ShutterKeyPressed;CameraButtons.ShutterKeyReleased += CameraButtons_ShutterKeyReleased;// 相机模式下，必须将捕获到的信息输出到 UI 上，系统才能响应硬件快门的事件（同理，摄像模式下，必须调用了 CaptureSource.Start() 之后系统才能响应硬件快门的事件）
                videoBrush.SetSource(_camera);}}protected override void OnNavigatingFrom(NavigatingCancelEventArgs e){// 清理相关资源CameraButtons.ShutterKeyHalfPressed -= CameraButtons_ShutterKeyHalfPressed;CameraButtons.ShutterKeyPressed -= CameraButtons_ShutterKeyPressed;CameraButtons.ShutterKeyReleased -= CameraButtons_ShutterKeyReleased;}void CameraButtons_ShutterKeyHalfPressed(object sender, EventArgs e){lblMsg.Text = "快门半按压";}void CameraButtons_ShutterKeyPressed(object sender, EventArgs e){lblMsg.Text = "快门全按压";}void CameraButtons_ShutterKeyReleased(object sender, EventArgs e){lblMsg.Text = "快门被释放";}}
}

2、演示如何自动对焦，以及如何自动对焦到指定的点

Focus.xaml

<phone:PhoneApplicationPage x:Class="Demo.Device.Camera.Focus"xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"xmlns:d="http://schemas.microsoft.com/expression/blend/2008"xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"FontFamily="{StaticResource PhoneFontFamilyNormal}"FontSize="{StaticResource PhoneFontSizeNormal}"Foreground="{StaticResource PhoneForegroundBrush}"SupportedOrientations="Portrait" Orientation="Portrait"mc:Ignorable="d" d:DesignHeight="768" d:DesignWidth="480"shell:SystemTray.IsVisible="True"><Grid x:Name="LayoutRoot" Background="Transparent"><StackPanel Orientation="Vertical"><Canvas Name="canvas" Width="480" Height="320" Tap="canvas_Tap"><Canvas.Background><VideoBrush x:Name="videoBrush"><VideoBrush.RelativeTransform><RotateTransform CenterX="0.5" CenterY="0.5" Angle="90" />VideoBrush.RelativeTransform>VideoBrush>Canvas.Background>Canvas><Button Name="btnFocus" Content="自动对焦" Click="btnFocus_Click" /><TextBlock Name="lblMsg" />StackPanel>Grid>phone:PhoneApplicationPage>

Focus.xaml.cs

/** 演示如何自动对焦，以及如何自动对焦到指定的点* * PhotoCamera - 用于提供相机功能*     Focus() - 让相机自动对焦*     FocusAtPoint(double x, double y) - 自动对焦到取景器上指定的点*         x, y - 取景器上需要对焦的点的坐标，取景器左上角坐标为 0,0，取景器右下角坐标为 1,1*     AutoFocusCompleted - 自动对焦完成后所触发的事件（事件参数为 CameraOperationCompletedEventArgs 类型）*     * * CameraOperationCompletedEventArgs*     Succeeded - 操作是否成功*     Exception - 异常信息*/using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using Microsoft.Phone.Controls;using Microsoft.Devices;
using System.Windows.Navigation;namespace Demo.Device.Camera
{public partial class Focus : PhoneApplicationPage{private PhotoCamera _camera;public Focus(){InitializeComponent();}protected override void OnNavigatedTo(NavigationEventArgs e){if (PhotoCamera.IsCameraTypeSupported(CameraType.Primary)){// 实例化 PhotoCamera，注册相关事件_camera = new PhotoCamera(CameraType.Primary);_camera.AutoFocusCompleted += _camera_AutoFocusCompleted;// 在 VideoBrush 上显示摄像头捕获到的实时信息
                videoBrush.SetSource(_camera);}}protected override void OnNavigatingFrom(NavigatingCancelEventArgs e){// 清理相关资源_camera.AutoFocusCompleted -= _camera_AutoFocusCompleted;}void _camera_AutoFocusCompleted(object sender, CameraOperationCompletedEventArgs e){if (e.Succeeded){Deployment.Current.Dispatcher.BeginInvoke(delegate(){lblMsg.Text = "自动对焦完成";});}else{Deployment.Current.Dispatcher.BeginInvoke(delegate(){lblMsg.Text = "自动对焦失败";});}}private void btnFocus_Click(object sender, RoutedEventArgs e){if (_camera.IsFocusSupported == true){try{// 开始自动对焦
                    _camera.Focus();lblMsg.Text = "开始自动对焦";}catch (Exception ex){this.Dispatcher.BeginInvoke(delegate(){lblMsg.Text = "自动对焦失败：" + ex.ToString();});}}else{this.Dispatcher.BeginInvoke(delegate(){lblMsg.Text = "相机不支持自动对焦";});}}private void canvas_Tap(object sender, System.Windows.Input.GestureEventArgs e){if (_camera != null){if (_camera.IsFocusAtPointSupported == true){try{// 获取用户触摸的点相对于 canvas 的坐标Point tapLocation = e.GetPosition(canvas);// 计算触摸点映射于取景器上的坐标（取景器左上角为0,0，右下角为1,1）double focusXPercent = tapLocation.X / canvas.Width;double focusYPercent = tapLocation.Y / canvas.Height;// 自动对焦到指定的点
                        _camera.FocusAtPoint(focusXPercent, focusYPercent);this.Dispatcher.BeginInvoke(delegate(){lblMsg.Text = String.Format("自动对焦到指定的点{0}X：{1:N2}{2}Y：{3:N2}", System.Environment.NewLine, focusXPercent, System.Environment.NewLine, focusYPercent);});}catch (Exception ex){this.Dispatcher.BeginInvoke(delegate(){lblMsg.Text = "自动对焦到指定的点失败：" + ex.ToString();});}}else{this.Dispatcher.BeginInvoke(delegate(){lblMsg.Text = "相机不支持自动对焦到指定的点";});}}}}
}

3、演示如何实时修改捕获到的视频帧

LiveAlter.xaml

<phone:PhoneApplicationPage x:Class="Demo.Device.Camera.LiveAlter"xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"xmlns:d="http://schemas.microsoft.com/expression/blend/2008"xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"FontFamily="{StaticResource PhoneFontFamilyNormal}"FontSize="{StaticResource PhoneFontSizeNormal}"Foreground="{StaticResource PhoneForegroundBrush}"SupportedOrientations="Landscape" Orientation="Landscape"mc:Ignorable="d" d:DesignHeight="480" d:DesignWidth="728"shell:SystemTray.IsVisible="True"><Grid x:Name="LayoutRoot" Background="Transparent"><StackPanel Orientation="Vertical"><Grid Width="480" Height="320" HorizontalAlignment="Left"><Canvas Visibility="Collapsed"><Canvas.Background><VideoBrush x:Name="videoBrush" />Canvas.Background>Canvas><Image x:Name="imgEffect" HorizontalAlignment="Left" />Grid><TextBlock Name="lblMsg" />StackPanel>Grid>phone:PhoneApplicationPage>

LiveAlter.xaml.cs

/** 演示如何实时处理摄像头捕获到的图像* * PhotoCamera - 用于提供相机功能*     PreviewResolution - 捕获到的图像的当前的分辨率（返回 System.Windows.Size 类型的结构体，其包含 Width 和 Height 字段）*     GetPreviewBufferArgb32(int[] pixelData) - 将当前捕获到的图像的 ARGB 数据复制到指定的缓冲区中* * * 注：* Resolution 指的是相机设置的分辨率* PreviewResolution 指的是系统针对显示设备缩放后的真实分辨率* 因为通常相机能够拍摄大于设备显示器的分辨率的图像，所以实时显示摄像头捕获到的图像时，系统会对其分辨率进行优化，PreviewResolution 就是优化后的数据*/using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using Microsoft.Phone.Controls;using Microsoft.Devices;
using System.Threading;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;namespace Demo.Device.Camera
{public partial class LiveAlter : PhoneApplicationPage{private PhotoCamera _camera = new PhotoCamera();// 用于显示处理后的图像private WriteableBitmap _writeableBitmap;// 有信号private static ManualResetEvent _manualReset = new ManualResetEvent(true);public LiveAlter(){InitializeComponent();}protected override void OnNavigatedTo(NavigationEventArgs e){if (PhotoCamera.IsCameraTypeSupported(CameraType.Primary)){// 实例化 PhotoCamera，并注册相关事件_camera = new PhotoCamera(CameraType.Primary);_camera.Initialized += _camera_Initialized;videoBrush.SetSource(_camera);}else{this.Dispatcher.BeginInvoke(delegate(){lblMsg.Text = "设备不支持主摄像头";});}}protected override void OnNavigatingFrom(NavigatingCancelEventArgs e){// 清理资源if (_camera != null){_camera.Dispose();_camera.Initialized -= _camera_Initialized;}}void _camera_Initialized(object sender, CameraOperationCompletedEventArgs e){// 新开线程去执行实时处理图片的任务Thread thread = new Thread(CameraToGray);thread.Start();this.Dispatcher.BeginInvoke(delegate(){// 让 Image 显示 WriteableBitmap 中的内容_writeableBitmap = new WriteableBitmap((int)_camera.PreviewResolution.Width, (int)_camera.PreviewResolution.Height);imgEffect.Source = _writeableBitmap;});}private void CameraToGray(){// 初始化缓冲区大小：图像宽和高的乘积int[] buffer = new int[(int)_camera.PreviewResolution.Width * (int)_camera.PreviewResolution.Height];try{while (true){// 实例化 ManualResetEvent 的时候，指定了其是有信号的_manualReset.WaitOne(); // 有信号则不阻塞，无信号则阻塞// 将当前捕获到的图像以 ARGB 的方式写入到缓冲区
                    _camera.GetPreviewBufferArgb32(buffer);// 将缓冲区中的每一个像素的颜色都转换为灰色系for (int i = 0; i < buffer.Length; i++){buffer[i] = ColorToGray(buffer[i]);}_manualReset.Reset(); // 设置为无信号
Deployment.Current.Dispatcher.BeginInvoke(delegate(){// 将处理后的图像数据保存到 WriteableBitmap 对象buffer.CopyTo(_writeableBitmap.Pixels, 0);// 重新绘制整个 WriteableBitmap 对象
                        _writeableBitmap.Invalidate();lblMsg.Text = "图像实时处理中";_manualReset.Set();  // 设置为有信号
                    });}}catch (Exception ex){this.Dispatcher.BeginInvoke(delegate(){lblMsg.Text = "图像处理失败：" + ex.ToString();});}}// 将指定的颜色转换成灰色系的颜色private int ColorToGray(int color){int gray = 0;int a = color >> 24;int r = (color & 0x00ff0000) >> 16;int g = (color & 0x0000ff00) >> 8;int b = (color & 0x000000ff);if ((r == g) && (g == b)){gray = color;}else{int i = (7 * r + 38 * g + 19 * b + 32) >> 6;gray = ((a & 0xFF) << 24) | ((i & 0xFF) << 16) | ((i & 0xFF) << 8) | (i & 0xFF);}return gray;}}
}

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