/// <summary>
/// Update preview image.
/// </summary>
async void UpdatePreviewImage()
{
double sourceImageWidthScale = imageCanvas.Width / this.sourceImagePixelWidth;
double sourceImageHeightScale = imageCanvas.Height / this.sourceImagePixelHeight;
Size previewImageSize = new Size(
this.selectedRegion.SelectedRect.Width / sourceImageWidthScale,
this.selectedRegion.SelectedRect.Height / sourceImageHeightScale);
double previewImageScale = 1;
if (previewImageSize.Width <= imageCanvas.Width &&
previewImageSize.Height <= imageCanvas.Height)
{
this.previewImage.Stretch = Windows.UI.Xaml.Media.Stretch.None;
}
else
{
this.previewImage.Stretch = Windows.UI.Xaml.Media.Stretch.Uniform;
previewImageScale = Math.Min(imageCanvas.Width / previewImageSize.Width,
imageCanvas.Height / previewImageSize.Height);
}
this.previewImage.Source = await CropBitmap.GetCroppedBitmapAsync(
this.sourceImageFile,
new Point(this.selectedRegion.SelectedRect.X / sourceImageWidthScale, this.selectedRegion.SelectedRect.Y / sourceImageHeightScale),
previewImageSize,
previewImageScale);
}
/// <summary>
/// Let user choose an image and load it.
/// </summary>
async private void openImageButton_Click(object sender, RoutedEventArgs e)
{
bool unsnapped = ((ApplicationView.Value != ApplicationViewState.Snapped) || ApplicationView.TryUnsnap());
if (!unsnapped)
{
NotifyUser("Cannot unsnap the sample.");
return;
}
FileOpenPicker openPicker = new FileOpenPicker();
openPicker.ViewMode = PickerViewMode.Thumbnail;
openPicker.SuggestedStartLocation = PickerLocationId.PicturesLibrary;
openPicker.FileTypeFilter.Add(".jpg");
openPicker.FileTypeFilter.Add(".jpeg");
openPicker.FileTypeFilter.Add(".bmp");
openPicker.FileTypeFilter.Add(".png");
StorageFile imgFile = await openPicker.PickSingleFileAsync();
if (imgFile != null)
{
this.previewImage.Source = null;
this.sourceImage.Source = null;
this.imageCanvas.Visibility = Windows.UI.Xaml.Visibility.Collapsed;
this.originalImageInfoText.Text = string.Empty;
this.selectInfoInBitmapText.Text = string.Empty;
this.saveImageButton.IsEnabled = false;
// Ensure the stream is disposed once the image is loaded
using (IRandomAccessStream fileStream = await imgFile.OpenAsync(Windows.Storage.FileAccessMode.Read))
{
this.sourceImageFile = imgFile;
BitmapDecoder decoder = await BitmapDecoder.CreateAsync(fileStream);
this.sourceImagePixelHeight = decoder.PixelHeight;
this.sourceImagePixelWidth = decoder.PixelWidth;
}
if (this.sourceImagePixelHeight < 2 * this.CornerSize ||
this.sourceImagePixelWidth < 2 * this.CornerSize)
{
this.NotifyUser(string.Format("Please select an image which is larger than {0}*{0}",
2 * this.CornerSize));
return;
}
else
{
double sourceImageScale = 1;
if (this.sourceImagePixelHeight < this.sourceImageGrid.ActualHeight &&
this.sourceImagePixelWidth < this.sourceImageGrid.ActualWidth)
{
this.sourceImage.Stretch = Windows.UI.Xaml.Media.Stretch.None;
}
else
{
sourceImageScale = Math.Min(this.sourceImageGrid.ActualWidth / this.sourceImagePixelWidth,
this.sourceImageGrid.ActualHeight / this.sourceImagePixelHeight);
this.sourceImage.Stretch = Windows.UI.Xaml.Media.Stretch.Uniform;
}
this.sourceImage.Source = await CropBitmap.GetCroppedBitmapAsync(
this.sourceImageFile,
new Point(0, 0),
new Size(this.sourceImagePixelWidth, this.sourceImagePixelHeight),
sourceImageScale);
this.originalImageInfoText.Text = string.Format("Original Image Size: {0}*{1} ",
this.sourceImagePixelWidth, this.sourceImagePixelHeight);
}
}
}