private async void FinishedPickingAssets(object sender, MultiAssetEventArgs args)
{
var results = new List <MediaFile>(24);
var tcs = new TaskCompletionSource <IList <MediaFile> >();
Debug.WriteLine("User finished picking assets. {0} items selected.", args.Assets.Length);
_preselectedAssets = args.Assets;
// For demo purposes: just show all chosen pictures in order every second
foreach (var asset in _preselectedAssets)
{
// Get information about the asset, e.g. file patch
asset.RequestContentEditingInput(new PHContentEditingInputRequestOptions(),
completionHandler: (input, options) =>
{
var path = input.FullSizeImageUrl.ToString();
path = path.Replace("file://", "");
var fileName = System.IO.Path.GetFileNameWithoutExtension(path);
var ext = System.IO.Path.GetExtension(path);
var imgOption = MediaFileGetImageOptions.CreateDefaultThumb();
var thumbImageBytes = AssetImageService.GetImageBytes(asset, imgOption);
var thumbnailImagePath =
MediaFileHelper.GetOutputPath(MediaFileType.Image, "TmpMedia",
$"{fileName}-THUMBNAIL{ext}");
System.IO.File.WriteAllBytes(thumbnailImagePath, thumbImageBytes);
results.Add(new MediaFile
{
Path = path,
PreviewPath = thumbnailImagePath,
Type = MediaFileType.Image
});
});
await Task.Delay(250);
}
tcs.TrySetResult(results);
_mediaPickTcs?.TrySetResult(await tcs.Task);
_preselectedAssets = null;
}
public async Task <string> CreatePreviewPath(string path, string type)
{
await Task.Delay(TimeSpan.FromMilliseconds(100));
var fileName = System.IO.Path.GetFileNameWithoutExtension(path);
var ext = System.IO.Path.GetExtension(path);
var strs = path.Split('/');
var assetResult = PHAsset.FetchAssetsUsingLocalIdentifiers(strs, null);
var asset = assetResult.firstObject as PHAsset;
var thumbImageBytes =
AssetImageService.GetImageBytes(asset, MediaFileGetImageOptions.CreateDefaultThumb());
var thumbnailImagePath =
MediaFileHelper.GetOutputPath(MediaFileType.Image, "TmpMedia",
$"{fileName}-THUMBNAIL{ext}");
System.IO.File.WriteAllBytes(thumbnailImagePath, thumbImageBytes);
return(thumbnailImagePath);
}
internal static byte[] GetImageBytes(PHAsset asset, MediaFileGetImageOptions options)
{
nfloat w = options.Width;
nfloat h = options.Height;
switch (options.Orientation)
{
case MediaFileImageOrientation.Left:
case MediaFileImageOrientation.LeftMirrored:
case MediaFileImageOrientation.Right:
case MediaFileImageOrientation.RightMirrored:
var wT = w;
w = h;
h = wT;
break;
}
if (w <= 0)
{
if (h > 0)
{
w = asset.PixelWidth * h / asset.PixelHeight;
}
else
{
w = asset.PixelWidth;
}
}
if (h <= 0)
{
h = asset.PixelHeight * w / asset.PixelWidth;
}
byte[] imageBytes = null;
PHImageManager.DefaultManager.RequestImageForAsset(
asset,
new CoreGraphics.CGSize(w, h),
ImageResizeAspectToPH(options.ResizeAspect),
new PHImageRequestOptions {
Synchronous = true, ResizeMode = PHImageRequestOptionsResizeMode.Exact
},
(requestedImage, info) =>
{
if (options.Orientation != MediaFileImageOrientation.Up ||
requestedImage.Size.Width != w ||
requestedImage.Size.Height != h)
{
var destW = w;
var destH = h;
if (options.ResizeAspect == MediaFileGetImageOptions.ImageResizeAspect.AspectFit)
{
var widthScale = w / requestedImage.Size.Width;
var heightScale = h / requestedImage.Size.Height;
var scale = (nfloat)Math.Min(widthScale, heightScale);
switch (options.Orientation)
{
case MediaFileImageOrientation.Left:
case MediaFileImageOrientation.LeftMirrored:
case MediaFileImageOrientation.Right:
case MediaFileImageOrientation.RightMirrored:
h = requestedImage.Size.Width * scale;
w = requestedImage.Size.Height * scale;
destW = h;
destH = w;
break;
default:
w = requestedImage.Size.Width * scale;
h = requestedImage.Size.Height * scale;
destW = w;
destH = h;
break;
}
}
else
{
switch (options.Orientation)
{
case MediaFileImageOrientation.Left:
case MediaFileImageOrientation.LeftMirrored:
case MediaFileImageOrientation.Right:
case MediaFileImageOrientation.RightMirrored:
var wT = w;
w = h;
h = wT;
break;
}
}
var cg = requestedImage.CGImage;
int bytesPerRow = (int)w * 4;
var ctx = new CoreGraphics.CGBitmapContext(null, (int)w, (int)h, 8, bytesPerRow,
cg.ColorSpace, CoreGraphics.CGImageAlphaInfo.PremultipliedLast);
Func <float, float> radians = (degrees) => { return(degrees * ((float)Math.PI / 180f)); };
switch (options.Orientation)
{
case MediaFileImageOrientation.UpMirrored:
ctx.TranslateCTM(w, 0);
ctx.ScaleCTM(-1f, 1f);
break;
case MediaFileImageOrientation.Down:
ctx.TranslateCTM(w, h);
ctx.RotateCTM(radians(180f));
break;
case MediaFileImageOrientation.DownMirrored:
ctx.TranslateCTM(0, h);
ctx.RotateCTM(radians(180f));
ctx.ScaleCTM(-1f, 1f);
break;
case MediaFileImageOrientation.Left:
ctx.TranslateCTM(w, 0);
ctx.RotateCTM(radians(90f));
break;
case MediaFileImageOrientation.LeftMirrored:
ctx.TranslateCTM(w, h);
ctx.RotateCTM(radians(270f));
ctx.ScaleCTM(1f, -1f);
break;
case MediaFileImageOrientation.Right:
ctx.TranslateCTM(0, h);
ctx.RotateCTM(radians(270f));
break;
case MediaFileImageOrientation.RightMirrored:
ctx.TranslateCTM(0, 0);
ctx.RotateCTM(radians(90f));
ctx.ScaleCTM(1f, -1f);
break;
default:
break;
}
ctx.DrawImage(new CoreGraphics.CGRect(0, 0, destW, destH), cg);
requestedImage = UIImage.FromImage(ctx.ToImage());
ctx.Dispose();
}
imageBytes = requestedImage.AsJPEG(options.Quality / 100f).ToArray();
requestedImage.Dispose();
});
return(imageBytes);
}
