Windows Phone 8.1应用程序全屏显示图像预览
本文关键字：显示图 显示 图像 Phone 应用程序 Windows | 更新日期: 2023-09-27 18:29:36
在我的Windows Phone 8.1应用程序上，我有摄像头功能，但我似乎无法全屏显示图像预览。有人能看到必须做什么吗？
ButtonCapture_Click初始化imagePreview，previewElement_Tapped实际拍摄快照。
Xaml：
<!--LayoutRoot is the root grid where all page content is placed-->
<Grid x:Name="LayoutRoot" Background="Transparent">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<!--TitlePanel contains the name of the application and page title-->
<StackPanel x:Name="TitlePanel" Grid.Row="0" Margin="0,18,0,18">
<TextBlock Text="StudyToolMobile" Style="{StaticResource TitleTextBlockStyle}" Margin="18,0"/>
</StackPanel>
<!--ContentPanel - place additional content here-->
<Grid x:Name="ContentPanel" Grid.Row="1" Margin="18,0,18,0">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="4*" />
<ColumnDefinition Width="2*" />
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="0" Grid.ColumnSpan="2" Style="{StaticResource BodyTextBlockStyle}" Text="Enter some text below and click Save to insert a new TodoItem item into your database" TextWrapping="Wrap"/>
<TextBox Grid.Row="1" Grid.Column="0" Name="TextInput" Text="" />
<StackPanel Grid.Row ="1" Grid.Column="1" Orientation="Horizontal">
<AppBarButton Label="Photo" Icon="Camera" Name="ButtonCapture"
Click="ButtonCapture_Click" Height="78" Width="62" />
<AppBarButton Label="Upload" Icon="Upload" Name="ButtonSave"
Click="ButtonSave_Click"/>
</StackPanel>
<Grid Grid.Row="2" Name="captureGrid" Grid.RowSpan="3" Grid.ColumnSpan="2"
Canvas.ZIndex="99" Background="{ThemeResource ApplicationPageBackgroundThemeBrush}"
Visibility="Collapsed">
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<CaptureElement Grid.Row="0" x:Name="previewElement" Tapped="previewElement_Tapped" />
<Image Grid.Row="0" Name="imagePreview" Visibility="Collapsed" Margin="0,262,0,115" />
<StackPanel Grid.Row="1" Name="captureButtons"
Orientation="Horizontal" Visibility="Collapsed">
<TextBlock Name="TextCapture" VerticalAlignment="Bottom" />
<AppBarButton Label="Retake" Icon="Redo" Name="ButtonRetake"
Click="ButtonRetake_Click" />
<AppBarButton Label="Cancel" Icon="Cancel" Name="ButtonCancel"
Click="ButtonCancel_Click" />
</StackPanel>
</Grid>
<TextBlock Grid.Row="2" Grid.ColumnSpan="2" Style="{StaticResource BodyTextBlockStyle}" Text="Click refresh below to load the unfinished TodoItems from your database. Use the checkbox to complete and update your TodoItems" TextWrapping="Wrap"/>
<Button Grid.Row="3" Grid.ColumnSpan="2" Name="ButtonRefresh" Click="ButtonRefresh_Click" HorizontalAlignment="Stretch">Refresh</Button>
<ListView Grid.Row="4" Grid.ColumnSpan="2" Name="ListItems">
<ListView.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Vertical">
<CheckBox Name="CheckBoxComplete" IsChecked="{Binding Complete, Mode=TwoWay}"
Checked="CheckBoxComplete_Checked" Content="{Binding Text}"
Margin="10,5" VerticalAlignment="Center"/>
<Image Name="ImageUpload" Source="{Binding ImageUri, Mode=OneWay}"
MaxHeight="150"/>
</StackPanel>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</Grid>
</Grid>
代码：
// Use a StorageFile to hold the captured image for upload.
StorageFile media = null;
MediaCapture cameraCapture;
bool IsCaptureInProgress;
private async Task CaptureImage()
{
// Capture a new photo or video from the device.
cameraCapture = new MediaCapture();
cameraCapture.Failed += cameraCapture_Failed;
// Initialize the camera for capture.
await cameraCapture.InitializeAsync();
cameraCapture.SetPreviewRotation(VideoRotation.Clockwise90Degrees);
cameraCapture.SetRecordRotation(VideoRotation.Clockwise90Degrees);
captureGrid.Visibility = Windows.UI.Xaml.Visibility.Visible;
previewElement.Visibility = Windows.UI.Xaml.Visibility.Visible;
previewElement.Source = cameraCapture;
await cameraCapture.StartPreviewAsync();
}
private async void previewElement_Tapped(object sender, TappedRoutedEventArgs e)
{
// Block multiple taps.
if (!IsCaptureInProgress)
{
IsCaptureInProgress = true;
Random rnd = new Random();
int number = rnd.Next(1, 20);
string numberString = number.ToString();
string jpgName = numberString + ".jpg";
// Create the temporary storage file.
media = await ApplicationData.Current.LocalFolder
.CreateFileAsync(jpgName, CreationCollisionOption.ReplaceExisting);
// Take the picture and store it locally as a JPEG.
await cameraCapture.CapturePhotoToStorageFileAsync(
ImageEncodingProperties.CreateJpeg(), media);
captureButtons.Visibility = Visibility.Visible;
// Use the stored image as the preview source.
BitmapImage tempBitmap = new BitmapImage(new Uri(media.Path));
imagePreview.Source = tempBitmap;
imagePreview.Visibility = Visibility.Visible;
previewElement.Visibility = Visibility.Collapsed;
IsCaptureInProgress = false;
}
}
private async void cameraCapture_Failed(MediaCapture sender, MediaCaptureFailedEventArgs errorEventArgs)
{
// It's safest to return this back onto the UI thread to show the message dialog.
MessageDialog dialog = new MessageDialog(errorEventArgs.Message);
await this.Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal,
async () => { await dialog.ShowAsync(); });
}
private async void ButtonCapture_Click(object sender, RoutedEventArgs e)
{
// Prevent multiple initializations.
ButtonCapture.IsEnabled = false;
await CaptureImage();
}
您已将"边距"设置为图像预览。将上下边距设置为0，这样图像将占用全部空间。。。
<Image Grid.Row="0" Name="imagePreview" Visibility="Collapsed" Margin="0" />
不要使用以下API：
cameraCapture.SetPreviewRotation(VideoRotation.Clockwise90Degrees);
cameraCapture.SetRecordRotation(VideoRotation.Clockwise90Degrees);
相反，要旋转预览和录制的视频，请参阅CameraStarterKit SDK示例：
/// <summary>
/// Gets the current orientation of the UI in relation to the device (when AutoRotationPreferences cannot be honored) and applies a corrective rotation to the preview
/// </summary>
private async Task SetPreviewRotationAsync()
{
// Only need to update the orientation if the camera is mounted on the device
if (_externalCamera) return;
// Calculate which way and how far to rotate the preview
int rotationDegrees = ConvertDisplayOrientationToDegrees(_displayOrientation);
// The rotation direction needs to be inverted if the preview is being mirrored
if (_mirroringPreview)
{
rotationDegrees = (360 - rotationDegrees) % 360;
}
// Add rotation metadata to the preview stream to make sure the aspect ratio / dimensions match when rendering and getting preview frames
var props = _mediaCapture.VideoDeviceController.GetMediaStreamProperties(MediaStreamType.VideoPreview);
props.Properties.Add(RotationKey, rotationDegrees);
await _mediaCapture.SetEncodingPropertiesAsync(MediaStreamType.VideoPreview, props, null);
}
和：
/// <summary>
/// Records an MP4 video to a StorageFile and adds rotation metadata to it
/// </summary>
/// <returns></returns>
private async Task StartRecordingAsync()
{
try
{
// Create storage file in Pictures Library
var videoFile = await KnownFolders.PicturesLibrary.CreateFileAsync("SimpleVideo.mp4", CreationCollisionOption.GenerateUniqueName);
var encodingProfile = MediaEncodingProfile.CreateMp4(VideoEncodingQuality.Auto);
// Calculate rotation angle, taking mirroring into account if necessary
var rotationAngle = 360 - ConvertDeviceOrientationToDegrees(GetCameraOrientation());
encodingProfile.Video.Properties.Add(RotationKey, PropertyValue.CreateInt32(rotationAngle));
Debug.WriteLine("Starting recording...");
await _mediaCapture.StartRecordToStorageFileAsync(encodingProfile, videoFile);
_isRecording = true;
Debug.WriteLine("Started recording!");
}
catch (Exception ex)
{
// File I/O errors are reported as exceptions
Debug.WriteLine("Exception when starting video recording: {0}", ex.ToString());
}
}