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[iOS] Fix MediaPicker.PickPhotosAsync returning empty list when selecting 4+ images with CompressionQuality set #34281

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Merged
kubaflo merged 2 commits into from
Mar 14, 2026
Merged

[iOS] Fix MediaPicker.PickPhotosAsync returning empty list when selecting 4+ images with CompressionQuality set #34281

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f69a3e8
Fixed-33954 : [iOS] MediaPicker.PickPhotosAsync unable to pick multip…
Vignesh-SF3580 Feb 12, 2026
1edf860
Addressed review concerns.
Vignesh-SF3580 Mar 3, 2026
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153 changes: 136 additions & 17 deletions src/Essentials/src/MediaPicker/MediaPicker.ios.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -283,17 +283,17 @@ static async Task<List<FileResult>> PickerResultsToMediaFiles(PHPickerResult[] r
{
using var originalStream = await result.OpenReadAsync();
using var rotatedStream = await ImageProcessor.RotateImageAsync(originalStream, result.FileName);

// Create a temp file for the rotated image
var tempFileName = $"{Guid.NewGuid()}{Path.GetExtension(result.FileName)}";
var tempFilePath = Path.Combine(Path.GetTempPath(), tempFileName);

using (var fileStream = File.Create(tempFilePath))
{
rotatedStream.Position = 0;
await rotatedStream.CopyToAsync(fileStream);
}

var rotatedResult = new FileResult(tempFilePath)
{
FileName = result.FileName,
Expand All @@ -316,7 +316,7 @@ static async Task<List<FileResult>> PickerResultsToMediaFiles(PHPickerResult[] r
var compressedResults = new List<FileResult>();
foreach (var result in fileResults)
{
var compressedResult = await CompressedUIImageFileResult.CreateCompressedFromFileResult(result, options?.MaximumWidth, options?.MaximumHeight, options?.CompressionQuality ?? 100, options?.RotateImage ?? false, options?.PreserveMetaData ?? true);
var compressedResult = new PHPickerProcessedFileResult(result, options?.MaximumWidth, options?.MaximumHeight, options?.CompressionQuality ?? 100, options?.RotateImage ?? false, options?.PreserveMetaData ?? true);
compressedResults.Add(compressedResult);
}
return compressedResults;
Expand Down Expand Up @@ -365,7 +365,7 @@ static FileResult DictionaryToMediaFile(NSDictionary info, MediaPickerOptions op
if (!assetUrl.Scheme.Equals("assets-library", StringComparison.OrdinalIgnoreCase))
{
var docResult = new UIDocumentFileResult(assetUrl);

// Apply rotation if needed and this is a photo
if (ImageProcessor.IsRotationNeeded(options) && IsImageFile(docResult.FileName))
{
Expand All @@ -380,7 +380,7 @@ static FileResult DictionaryToMediaFile(NSDictionary info, MediaPickerOptions op
// If rotation fails, continue with the original file
}
}

return docResult;
}

Expand Down Expand Up @@ -411,7 +411,7 @@ static FileResult DictionaryToMediaFile(NSDictionary info, MediaPickerOptions op
{
img = img.NormalizeOrientation();
}

return new CompressedUIImageFileResult(img, null, options?.MaximumWidth, options?.MaximumHeight, options?.CompressionQuality ?? 100);
}
}
Expand All @@ -423,7 +423,7 @@ static FileResult DictionaryToMediaFile(NSDictionary info, MediaPickerOptions op

string originalFilename = PHAssetResource.GetAssetResources(phAsset).FirstOrDefault()?.OriginalFilename;
var assetResult = new PHAssetFileResult(assetUrl, phAsset, originalFilename);

// Apply rotation if needed and this is a photo
if (ImageProcessor.IsRotationNeeded(options) && IsImageFile(assetResult.FileName))
{
Expand All @@ -438,41 +438,41 @@ static FileResult DictionaryToMediaFile(NSDictionary info, MediaPickerOptions op
// If rotation fails, continue with the original file
}
}

return assetResult;
}

// Helper method to check if a file is an image based on extension
static bool IsImageFile(string fileName)
{
if (string.IsNullOrEmpty(fileName))
return false;

var ext = Path.GetExtension(fileName)?.ToLowerInvariant();
return ext == ".jpg" || ext == ".jpeg" || ext == ".png" || ext == ".heic" || ext == ".heif";
}

// Helper method to rotate an image file
static async Task<FileResult> RotateImageFile(FileResult original)
{
if (original == null)
return null;

try
{
using var originalStream = await original.OpenReadAsync();
using var rotatedStream = await ImageProcessor.RotateImageAsync(originalStream, original.FileName);

// Create a temp file for the rotated image
var tempFileName = $"{Guid.NewGuid()}{Path.GetExtension(original.FileName)}";
var tempFilePath = Path.Combine(Path.GetTempPath(), tempFileName);

using (var fileStream = File.Create(tempFilePath))
{
rotatedStream.Position = 0;
await rotatedStream.CopyToAsync(fileStream);
}

return new FileResult(tempFilePath, original.FileName);
}
catch (Exception ex)
Expand All @@ -481,7 +481,7 @@ static async Task<FileResult> RotateImageFile(FileResult original)
return original;
}
}

class PhotoPickerDelegate : UIImagePickerControllerDelegate
{
public Action<NSDictionary> CompletedHandler { get; set; }
Expand Down Expand Up @@ -739,4 +739,123 @@ public void Dispose()
GC.SuppressFinalize(this);
}
}

/// <summary>
/// Wrapper that applies compression lazily when the stream is opened.
/// This avoids iOS resource limits when processing multiple photos.
/// </summary>
class PHPickerProcessedFileResult : FileResult, IDisposable
{
readonly FileResult _originalResult;
readonly int? _maximumWidth;
readonly int? _maximumHeight;
readonly int _compressionQuality;
readonly bool _rotateImage;
readonly bool _preserveMetaData;

// Cached result of the first call to PlatformOpenReadAsync to avoid re-processing
byte[] _cachedData;

internal PHPickerProcessedFileResult(FileResult originalResult, int? maximumWidth, int? maximumHeight, int compressionQuality, bool rotateImage, bool preserveMetaData)
: base()
{
_originalResult = originalResult;
_maximumWidth = maximumWidth;
_maximumHeight = maximumHeight;
_compressionQuality = compressionQuality;
_rotateImage = rotateImage;
_preserveMetaData = preserveMetaData;

// Copy metadata from original, adjusting extension for compressed output
var originalFileName = originalResult.FileName;
var originalFullPath = originalResult.FullPath;
var originalContentType = originalResult.ContentType;

// Preserve the original format: PNG stays PNG, everything else compresses to JPEG.
// When no compression is applied (quality == 100), preserve the original extension as-is.
var originalWasPng = !string.IsNullOrEmpty(originalFileName) &&
Path.GetExtension(originalFileName).Equals(".png", StringComparison.OrdinalIgnoreCase);
string outputExtension;
if (compressionQuality == 100)
outputExtension = Path.GetExtension(originalFileName ?? string.Empty);
else if (originalWasPng)
outputExtension = ".png";
else
outputExtension = ".jpg";

FileName = !string.IsNullOrEmpty(originalFileName) && !string.IsNullOrEmpty(outputExtension)
? Path.ChangeExtension(originalFileName, outputExtension)
: originalFileName;

FullPath = !string.IsNullOrEmpty(originalFullPath) && !string.IsNullOrEmpty(outputExtension)
? Path.ChangeExtension(originalFullPath, outputExtension)
: originalFullPath;

ContentType = string.Equals(outputExtension, ".png", StringComparison.OrdinalIgnoreCase)
? "image/png"
: string.Equals(outputExtension, ".jpg", StringComparison.OrdinalIgnoreCase) || string.Equals(outputExtension, ".jpeg", StringComparison.OrdinalIgnoreCase)
? "image/jpeg"
: originalContentType;
}

internal override async Task<Stream> PlatformOpenReadAsync()
{
// Return cached result on subsequent calls to avoid re-processing
if (_cachedData is not null)
return new MemoryStream(_cachedData, writable: false);

// Load the original stream into memory once to avoid multiple expensive NSItemProvider loads.
byte[] originalData;
using (var originalStream = await _originalResult.OpenReadAsync())
using (var buffer = new MemoryStream())
{
await originalStream.CopyToAsync(buffer);
originalData = buffer.ToArray();
}

Stream processedStream = null;
try
{
// processedStream is always an independent MemoryStream from ImageProcessor.ProcessImageAsync;
// it does not reference or depend on originalStream after this call completes.
using var originalForProcessing = new MemoryStream(originalData, writable: false);
processedStream = await ImageProcessor.ProcessImageAsync(
originalForProcessing,
_maximumWidth,
_maximumHeight,
_compressionQuality,
_originalResult.FileName,
_rotateImage,
_preserveMetaData);
}
catch
{
// Swallow processing exceptions and fall back to the original data.
processedStream = null;
}

if (processedStream is null)
{
// Fall back to the original data if processing failed or returned null.
_cachedData = originalData;
}
else
{
using (processedStream)
using (var buffer = new MemoryStream())
{
await processedStream.CopyToAsync(buffer);
_cachedData = buffer.ToArray();
}
}

return new MemoryStream(_cachedData, writable: false);
}

public void Dispose()
{
(_originalResult as IDisposable)?.Dispose();
GC.SuppressFinalize(this);
}
}
}
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