Metro style app Image scale, crop. Open and save the image

Metro style app

I. Image scale and crop operations

    public class PhotoEdit    {        public async static Task<WriteableBitmap> ScaleAndCorpPhoto(IStorageFile file)        {            if (file == null) return null;            // create a stream from the file and decode the image            var fileStream = await file.OpenAsync(Windows.Storage.FileAccessMode.Read);            BitmapDecoder decoder = await BitmapDecoder.CreateAsync(fileStream);            BitmapTransform transform = new BitmapTransform();            BitmapBounds bounds = new BitmapBounds();            transform.ScaledWidth = 500;            transform.ScaledHeight = 500;            const int croppedHeight = 400;            const int croppedWidth = 400;            bounds.Height = croppedHeight;            bounds.Width = croppedWidth;            bounds.X = 0;            bounds.Y = 0;            transform.Bounds = bounds;            // Get the pixels in Bgra8 to match what the WriteableBitmap will expect            PixelDataProvider pixelData = await decoder.GetPixelDataAsync(BitmapPixelFormat.Bgra8, BitmapAlphaMode.Straight, transform, ExifOrientationMode.RespectExifOrientation, ColorManagementMode.ColorManageToSRgb);            byte[] pixels = pixelData.DetachPixelData();            // And stream them into a WriteableBitmap             WriteableBitmap cropBmp = new WriteableBitmap(croppedHeight, croppedWidth);            Stream pixStream = cropBmp.PixelBuffer.AsStream();            pixStream.Write(pixels, 0, pixels.Length);            return cropBmp;         }    }

Call Method

Private async system. threading. tasks. task scaleandcorpphoto () {fileopenpicker = new fileopenpicker (); fileopenpicker. commitbuttontext = "open"; fileopenpicker. filetypefilter. insert (0 ,". jpg "); storagefile file = await fileopenpicker. picksinglefileasync (); If (file = NULL) return; image. source = await photoedit. scaleandcorpphoto (File );}

Ii. Opening and saving images

1. Open the image. Select the image to be displayed and display the image in the image control.

       private static BitmapImage srcImage = new BitmapImage();        private static WriteableBitmap wbsrcImage;        public async static void OpenImage(Image ImageOne)        {            FileOpenPicker imagePicker = new FileOpenPicker            {                ViewMode = PickerViewMode.Thumbnail,                SuggestedStartLocation = PickerLocationId.PicturesLibrary,                FileTypeFilter = { ".jpg", ".jpeg", ".png", ".bmp" }            };            Guid decoderId;            StorageFile imageFile = await imagePicker.PickSingleFileAsync();            if (imageFile != null)            {                srcImage = new BitmapImage();                using (IRandomAccessStream stream = await imageFile.OpenAsync(FileAccessMode.Read))                {                    srcImage.SetSource(stream);                    switch (imageFile.FileType.ToLower())                    {                        case ".jpg":                        case ".jpeg":                            decoderId = Windows.Graphics.Imaging.BitmapDecoder.JpegDecoderId;                            break;                        case ".bmp":                            decoderId = Windows.Graphics.Imaging.BitmapDecoder.BmpDecoderId;                            break;                        case ".png":                            decoderId = Windows.Graphics.Imaging.BitmapDecoder.PngDecoderId;                            break;                        default:                            return;                    }                    Windows.Graphics.Imaging.BitmapDecoder decoder = await Windows.Graphics.Imaging.BitmapDecoder.CreateAsync(decoderId, stream);                    int width = (int)decoder.PixelWidth;                    int height = (int)decoder.PixelHeight;                    Windows.Graphics.Imaging.PixelDataProvider dataprovider = await decoder.GetPixelDataAsync();                    byte[] pixels = dataprovider.DetachPixelData();                    wbsrcImage = new WriteableBitmap(width, height);                    Stream pixelStream = wbsrcImage.PixelBuffer.AsStream();                    //rgba in original                       //to display ,convert tobgra                        for (int i = 0; i < pixels.Length; i += 4)                    {                        byte temp = pixels[i];                        pixels[i] = pixels[i + 2];                        pixels[i + 2] = temp;                    }                    pixelStream.Write(pixels, 0, pixels.Length);                    pixelStream.Dispose();                    stream.Dispose();                }                ImageOne.Source = wbsrcImage;                ImageOne.Width = wbsrcImage.PixelWidth;                ImageOne.Height = wbsrcImage.PixelHeight;            }        }

2. Save the image. Save the obtained writeablebitmap. For example, you can save the scale and crop images.

        public async static Task SaveImage(WriteableBitmap src)        {            FileSavePicker save = new FileSavePicker();            save.SuggestedStartLocation = PickerLocationId.PicturesLibrary;            save.DefaultFileExtension = ".jpg";            save.SuggestedFileName = "newimage";            save.FileTypeChoices.Add(".bmp", new List<string>() { ".bmp" });            save.FileTypeChoices.Add(".png", new List<string>() { ".png" });            save.FileTypeChoices.Add(".jpg", new List<string>() { ".jpg", ".jpeg" });            StorageFile savedItem = await save.PickSaveFileAsync();            try            {                Guid encoderId;                switch (savedItem.FileType.ToLower())                {                    case ".jpg":                        encoderId = BitmapEncoder.JpegEncoderId;                        break;                    case ".bmp":                        encoderId = BitmapEncoder.BmpEncoderId;                        break;                    case ".png":                    default:                        encoderId = BitmapEncoder.PngEncoderId;                        break;                }                IRandomAccessStream fileStream = await savedItem.OpenAsync(Windows.Storage.FileAccessMode.ReadWrite);                BitmapEncoder encoder = await BitmapEncoder.CreateAsync(encoderId, fileStream);                Stream pixelStream = src.PixelBuffer.AsStream();                byte[] pixels = new byte[pixelStream.Length];                pixelStream.Read(pixels, 0, pixels.Length);                //pixal format shouldconvert to rgba8                 for (int i = 0; i < pixels.Length; i += 4)                {                    byte temp = pixels[i];                    pixels[i] = pixels[i + 2];                    pixels[i + 2] = temp;                }                encoder.SetPixelData(                  BitmapPixelFormat.Rgba8,                  BitmapAlphaMode.Straight,                  (uint)src.PixelWidth,                  (uint)src.PixelHeight,                  96, // Horizontal DPI                   96, // Vertical DPI                   pixels                  );                await encoder.FlushAsync();            }            catch (Exception e)            {                throw e;            }        }