Okay, I'm trying to do some work analyzing heuristics of an image in a WPF app. When the user chooses the image file location, I want to open the image in the codebehind, check the colors of the image, and output them in an application. However to properly check the pixels of the image I need to acquire the dimensions to load it to a WriteableBitmap that can get me the pixel colors.
When I open a stream to the file a second time the app just hangs. Here's the code:
private static async Task<Dictionary<Color, int>> GetColorCountsAsync(string path)
{
var colorCounts = new Dictionary<Color, int>();
var absolutePath = string.Format(@"{0}\{1}",Directory.GetCurrentDirectory(),path);
var dimension = await GetBitmapDimensions(absolutePath); //Method below - opens via StorageFile
var file = await StorageFile.GetFileFromPathAsync(absolutePath); //Hangs forever
using (var stream = await file.OpenStreamForReadAsync().ConfigureAwait(false))
{
var pixelWidth = dimension.Width;
var pixelHeight = dimension.Height;
var bitmap = new WriteableBitmap(pixelWidth, pixelHeight);
bitmap.SetSource(stream.AsRandomAccessStream());
using (var buffer = bitmap.PixelBuffer.AsStream())
{
var pixels = new byte[4 * pixelWidth * pixelHeight];
buffer.Read(pixels, 0, pixels.Length);
for (var y = 0; y < pixelHeight; y++)
{
for (var x = 0; x < pixelWidth; x++)
{
var index = ((y * pixelWidth) + x) * 4;
var alpha = pixels[index + 4];
var red = pixels[index + 2];
var green = pixels[index + 1];
var blue = pixels[index + 0];
var color = Color.FromArgb(alpha, red, green, blue);
if (!colorCounts.ContainsKey(color))
{
colorCounts.Add(color, 0);
}
colorCounts[color] = colorCounts[color] + 1;
}
}
}
}
return colorCounts;
}
private static async Task<Dimension> GetBitmapDimensions(string absolutePath)
{
var file = await StorageFile.GetFileFromPathAsync(absolutePath);
var bitmapImage = new BitmapImage();
using (var fileStream = await file.OpenAsync(FileAccessMode.Read))
{
bitmapImage.SetSource(fileStream);
}
return new Dimension { Height = bitmapImage.PixelHeight, Width = bitmapImage.PixelWidth };
}
I can't close the bitmap image nor dispose it - what's causing the app to freeze?
