/// <summary>
/// This is event handler for 'Extract' button.
/// Captures image from camera ,recognizes text and displays it.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private async void ExtractButton_Tapped(object sender, Windows.UI.Xaml.Input.TappedRoutedEventArgs e)
{
//Get information about the preview.
var previewProperties = mediaCapture.VideoDeviceController.GetMediaStreamProperties(MediaStreamType.VideoPreview) as VideoEncodingProperties;
int videoFrameWidth = (int)previewProperties.Width;
int videoFrameHeight = (int)previewProperties.Height;
// In portrait modes, the width and height must be swapped for the VideoFrame to have the correct aspect ratio and avoid letterboxing / black bars.
if (!externalCamera && (displayInformation.CurrentOrientation == DisplayOrientations.Portrait || displayInformation.CurrentOrientation == DisplayOrientations.PortraitFlipped))
{
videoFrameWidth = (int)previewProperties.Height;
videoFrameHeight = (int)previewProperties.Width;
}
// Create the video frame to request a SoftwareBitmap preview frame.
var videoFrame = new VideoFrame(BitmapPixelFormat.Bgra8, videoFrameWidth, videoFrameHeight);
// Capture the preview frame.
using (var currentFrame = await mediaCapture.GetPreviewFrameAsync(videoFrame))
{
// Collect the resulting frame.
SoftwareBitmap bitmap = currentFrame.SoftwareBitmap;
OcrEngine ocrEngine = OcrEngine.TryCreateFromLanguage(ocrLanguage);
if (ocrEngine == null)
{
rootPage.NotifyUser(ocrLanguage.DisplayName + " is not supported.", NotifyType.ErrorMessage);
return;
}
var imgSource = new WriteableBitmap(bitmap.PixelWidth, bitmap.PixelHeight);
bitmap.CopyToBuffer(imgSource.PixelBuffer);
PreviewImage.Source = imgSource;
var ocrResult = await ocrEngine.RecognizeAsync(bitmap);
// Used for text overlay.
// Prepare scale transform for words since image is not displayed in original format.
var scaleTrasform = new ScaleTransform
{
CenterX = 0,
CenterY = 0,
ScaleX = PreviewControl.ActualWidth / bitmap.PixelWidth,
ScaleY = PreviewControl.ActualHeight / bitmap.PixelHeight
};
if (ocrResult.TextAngle != null)
{
// If text is detected under some angle in this sample scenario we want to
// overlay word boxes over original image, so we rotate overlay boxes.
TextOverlay.RenderTransform = new RotateTransform
{
Angle = (double)ocrResult.TextAngle,
CenterX = PreviewImage.ActualWidth / 2,
CenterY = PreviewImage.ActualHeight / 2
};
}
// Iterate over recognized lines of text.
foreach (var line in ocrResult.Lines)
{
// Iterate over words in line.
foreach (var word in line.Words)
{
// Define the TextBlock.
var wordTextBlock = new TextBlock()
{
Text = word.Text,
Style = (Style)this.Resources["ExtractedWordTextStyle"]
};
WordOverlay wordBoxOverlay = new WordOverlay(word);
// Keep references to word boxes.
wordBoxes.Add(wordBoxOverlay);
// Define position, background, etc.
var overlay = new Border()
{
Child = wordTextBlock,
Style = (Style)this.Resources["HighlightedWordBoxHorizontalLine"]
};
// Bind word boxes to UI.
overlay.SetBinding(Border.MarginProperty, wordBoxOverlay.CreateWordPositionBinding());
overlay.SetBinding(Border.WidthProperty, wordBoxOverlay.CreateWordWidthBinding());
overlay.SetBinding(Border.HeightProperty, wordBoxOverlay.CreateWordHeightBinding());
// Put the filled textblock in the results grid.
TextOverlay.Children.Add(overlay);
}
}
rootPage.NotifyUser("Image processed using " + ocrEngine.RecognizerLanguage.DisplayName + " language.", NotifyType.StatusMessage);
}
UpdateWordBoxTransform();
PreviewControl.Visibility = Visibility.Collapsed;
Image.Visibility = Visibility.Visible;
ExtractButton.Visibility = Visibility.Collapsed;
CameraButton.Visibility = Visibility.Visible;
}
/// <summary>
/// This is event handler for 'Extract' button.
/// Recognizes text from image and displays it.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private async void ExtractButton_Tapped(object sender, Windows.UI.Xaml.Input.TappedRoutedEventArgs e)
{
ClearResults();
// Check if OcrEngine supports image resoulution.
if (bitmap.PixelWidth > OcrEngine.MaxImageDimension || bitmap.PixelHeight > OcrEngine.MaxImageDimension)
{
rootPage.NotifyUser(
String.Format("Bitmap dimensions ({0}x{1}) are too big for OCR.", bitmap.PixelWidth, bitmap.PixelHeight) +
"Max image dimension is " + OcrEngine.MaxImageDimension + ".",
NotifyType.ErrorMessage);
return;
}
OcrEngine ocrEngine = null;
if (UserLanguageToggle.IsOn)
{
// Try to create OcrEngine for first supported language from UserProfile.GlobalizationPreferences.Languages list.
// If none of the languages are available on device, method returns null.
ocrEngine = OcrEngine.TryCreateFromUserProfileLanguages();
}
else
{
// Try to create OcrEngine for specified language.
// If language is not supported on device, method returns null.
ocrEngine = OcrEngine.TryCreateFromLanguage(LanguageList.SelectedValue as Language);
}
if (ocrEngine != null)
{
// Recognize text from image.
var ocrResult = await ocrEngine.RecognizeAsync(bitmap);
// Display recognized text.
ExtractedTextBox.Text = ocrResult.Text;
if (ocrResult.TextAngle != null)
{
// If text is detected under some angle in this sample scenario we want to
// overlay word boxes over original image, so we rotate overlay boxes.
TextOverlay.RenderTransform = new RotateTransform
{
Angle = (double)ocrResult.TextAngle,
CenterX = PreviewImage.ActualWidth / 2,
CenterY = PreviewImage.ActualHeight / 2
};
}
// Create overlay boxes over recognized words.
foreach (var line in ocrResult.Lines)
{
Rect lineRect = Rect.Empty;
foreach (var word in line.Words)
{
lineRect.Union(word.BoundingRect);
}
// Determine if line is horizontal or vertical.
// Vertical lines are supported only in Chinese Traditional and Japanese languages.
bool isVerticalLine = lineRect.Height > lineRect.Width;
foreach (var word in line.Words)
{
WordOverlay wordBoxOverlay = new WordOverlay(word);
// Keep references to word boxes.
wordBoxes.Add(wordBoxOverlay);
// Define overlay style.
var overlay = new Border()
{
Style = isVerticalLine ?
(Style)this.Resources["HighlightedWordBoxVerticalLine"] :
(Style)this.Resources["HighlightedWordBoxHorizontalLine"]
};
// Bind word boxes to UI.
overlay.SetBinding(Border.MarginProperty, wordBoxOverlay.CreateWordPositionBinding());
overlay.SetBinding(Border.WidthProperty, wordBoxOverlay.CreateWordWidthBinding());
overlay.SetBinding(Border.HeightProperty, wordBoxOverlay.CreateWordHeightBinding());
// Put the filled textblock in the results grid.
TextOverlay.Children.Add(overlay);
}
}
// Rescale word boxes to match current UI size.
UpdateWordBoxTransform();
rootPage.NotifyUser(
"Image is OCRed for " + ocrEngine.RecognizerLanguage.DisplayName + " language.",
NotifyType.StatusMessage);
}
else
{
rootPage.NotifyUser("Selected language is not available.", NotifyType.ErrorMessage);
}
}
/// <summary>
/// This is event handler for 'Extract' button.
/// Captures image from camera ,recognizes text and displays it.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private async void ExtractButton_Tapped(object sender, Windows.UI.Xaml.Input.TappedRoutedEventArgs e)
{
//Get information about the preview.
var previewProperties = mediaCapture.VideoDeviceController.GetMediaStreamProperties(MediaStreamType.VideoPreview) as VideoEncodingProperties;
int videoFrameWidth = (int)previewProperties.Width;
int videoFrameHeight = (int)previewProperties.Height;
// In portrait modes, the width and height must be swapped for the VideoFrame to have the correct aspect ratio and avoid letterboxing / black bars.
if (!externalCamera && (displayInformation.CurrentOrientation == DisplayOrientations.Portrait || displayInformation.CurrentOrientation == DisplayOrientations.PortraitFlipped))
{
videoFrameWidth = (int)previewProperties.Height;
videoFrameHeight = (int)previewProperties.Width;
}
// Create the video frame to request a SoftwareBitmap preview frame.
var videoFrame = new VideoFrame(BitmapPixelFormat.Bgra8, videoFrameWidth, videoFrameHeight);
// Capture the preview frame.
using (var currentFrame = await mediaCapture.GetPreviewFrameAsync(videoFrame))
{
// Collect the resulting frame.
SoftwareBitmap bitmap = currentFrame.SoftwareBitmap;
OcrEngine ocrEngine = OcrEngine.TryCreateFromLanguage(ocrLanguage);
if (ocrEngine == null)
{
rootPage.NotifyUser(ocrLanguage.DisplayName + " is not supported.", NotifyType.ErrorMessage);
return;
}
var imgSource = new WriteableBitmap(bitmap.PixelWidth, bitmap.PixelHeight);
bitmap.CopyToBuffer(imgSource.PixelBuffer);
PreviewImage.Source = imgSource;
var ocrResult = await ocrEngine.RecognizeAsync(bitmap);
// Used for text overlay.
// Prepare scale transform for words since image is not displayed in original format.
var scaleTrasform = new ScaleTransform
{
CenterX = 0,
CenterY = 0,
ScaleX = PreviewControl.ActualWidth / bitmap.PixelWidth,
ScaleY = PreviewControl.ActualHeight / bitmap.PixelHeight
};
if (ocrResult.TextAngle != null)
{
// If text is detected under some angle in this sample scenario we want to
// overlay word boxes over original image, so we rotate overlay boxes.
TextOverlay.RenderTransform = new RotateTransform
{
Angle = (double)ocrResult.TextAngle,
CenterX = PreviewImage.ActualWidth / 2,
CenterY = PreviewImage.ActualHeight / 2
};
}
// Iterate over recognized lines of text.
foreach (var line in ocrResult.Lines)
{
// Iterate over words in line.
foreach (var word in line.Words)
{
// Define the TextBlock.
var wordTextBlock = new TextBlock()
{
Text = word.Text,
Style = (Style)this.Resources["ExtractedWordTextStyle"]
};
WordOverlay wordBoxOverlay = new WordOverlay(word);
// Keep references to word boxes.
wordBoxes.Add(wordBoxOverlay);
// Define position, background, etc.
var overlay = new Border()
{
Child = wordTextBlock,
Style = (Style)this.Resources["HighlightedWordBoxHorizontalLine"]
};
// Bind word boxes to UI.
overlay.SetBinding(Border.MarginProperty, wordBoxOverlay.CreateWordPositionBinding());
overlay.SetBinding(Border.WidthProperty, wordBoxOverlay.CreateWordWidthBinding());
overlay.SetBinding(Border.HeightProperty, wordBoxOverlay.CreateWordHeightBinding());
// Put the filled textblock in the results grid.
TextOverlay.Children.Add(overlay);
}
}
rootPage.NotifyUser("Image processed using " + ocrEngine.RecognizerLanguage.DisplayName + " language.", NotifyType.StatusMessage);
}
UpdateWordBoxTransform();
PreviewControl.Visibility = Visibility.Collapsed;
Image.Visibility = Visibility.Visible;
ExtractButton.Visibility = Visibility.Collapsed;
CameraButton.Visibility = Visibility.Visible;
}
/// <summary>
/// This is event handler for 'Extract' button.
/// Recognizes text from image and displays it.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private async void ExtractButton_Tapped(object sender, Windows.UI.Xaml.Input.TappedRoutedEventArgs e)
{
ClearResults();
// Check if OcrEngine supports image resoulution.
if (bitmap.PixelWidth > OcrEngine.MaxImageDimension || bitmap.PixelHeight > OcrEngine.MaxImageDimension)
{
rootPage.NotifyUser(
String.Format("Bitmap dimensions ({0}x{1}) are too big for OCR.", bitmap.PixelWidth, bitmap.PixelHeight) +
"Max image dimension is " + OcrEngine.MaxImageDimension + ".",
NotifyType.ErrorMessage);
return;
}
OcrEngine ocrEngine = null;
if (UserLanguageToggle.IsOn)
{
// Try to create OcrEngine for first supported language from UserProfile.GlobalizationPreferences.Languages list.
// If none of the languages are available on device, method returns null.
ocrEngine = OcrEngine.TryCreateFromUserProfileLanguages();
}
else
{
// Try to create OcrEngine for specified language.
// If language is not supported on device, method returns null.
ocrEngine = OcrEngine.TryCreateFromLanguage(LanguageList.SelectedValue as Language);
}
if (ocrEngine != null)
{
// Recognize text from image.
var ocrResult = await ocrEngine.RecognizeAsync(bitmap);
// Display recognized text.
ExtractedTextBox.Text = ocrResult.Text;
if (ocrResult.TextAngle != null)
{
// If text is detected under some angle in this sample scenario we want to
// overlay word boxes over original image, so we rotate overlay boxes.
TextOverlay.RenderTransform = new RotateTransform
{
Angle = (double)ocrResult.TextAngle,
CenterX = PreviewImage.ActualWidth / 2,
CenterY = PreviewImage.ActualHeight / 2
};
}
// Create overlay boxes over recognized words.
foreach (var line in ocrResult.Lines)
{
Rect lineRect = Rect.Empty;
foreach (var word in line.Words)
{
lineRect.Union(word.BoundingRect);
}
// Determine if line is horizontal or vertical.
// Vertical lines are supported only in Chinese Traditional and Japanese languages.
bool isVerticalLine = lineRect.Height > lineRect.Width;
foreach (var word in line.Words)
{
WordOverlay wordBoxOverlay = new WordOverlay(word);
// Keep references to word boxes.
wordBoxes.Add(wordBoxOverlay);
// Define overlay style.
var overlay = new Border()
{
Style = isVerticalLine ?
(Style)this.Resources["HighlightedWordBoxVerticalLine"] :
(Style)this.Resources["HighlightedWordBoxHorizontalLine"]
};
// Bind word boxes to UI.
overlay.SetBinding(Border.MarginProperty, wordBoxOverlay.CreateWordPositionBinding());
overlay.SetBinding(Border.WidthProperty, wordBoxOverlay.CreateWordWidthBinding());
overlay.SetBinding(Border.HeightProperty, wordBoxOverlay.CreateWordHeightBinding());
// Put the filled textblock in the results grid.
TextOverlay.Children.Add(overlay);
}
}
// Rescale word boxes to match current UI size.
UpdateWordBoxTransform();
rootPage.NotifyUser(
"Image is OCRed for " + ocrEngine.RecognizerLanguage.DisplayName + " language.",
NotifyType.StatusMessage);
}
else
{
rootPage.NotifyUser("Selected language is not available.", NotifyType.ErrorMessage);
}
}