public ImageCache(FileDatabase fileDatabase) :
base(fileDatabase)
{
this.CurrentDifferenceState = ImageDifference.Unaltered;
this.differenceBitmapCache = new Dictionary<ImageDifference, BitmapSource>();
this.mostRecentlyUsedIDs = new MostRecentlyUsedList<long>(Constant.Images.BitmapCacheSize);
this.prefetechesByID = new ConcurrentDictionary<long, Task>();
this.unalteredBitmapsByID = new ConcurrentDictionary<long, BitmapSource>();
}
public void MoveToNextStateInPreviousNextDifferenceCycle()
{
Debug.Assert((this.Current != null) && (this.Current.IsVideo == false), "No current file or current file is an image.");
// always go to unaltered from combined difference
if (this.CurrentDifferenceState == ImageDifference.Combined)
{
this.CurrentDifferenceState = ImageDifference.Unaltered;
return;
}
if (!this.Current.IsDisplayable())
{
// can't calculate differences for files which aren't displayble
this.CurrentDifferenceState = ImageDifference.Unaltered;
return;
}
else
{
// move to next state in cycle, wrapping around as needed
this.CurrentDifferenceState = (this.CurrentDifferenceState >= ImageDifference.Next) ? ImageDifference.Previous : ++this.CurrentDifferenceState;
}
// unaltered is always displayable; no more checks required
if (this.CurrentDifferenceState == ImageDifference.Unaltered)
{
return;
}
// can't calculate previous or next difference for the first or last file in the image set, respectively
// can't calculate difference if needed file isn't displayable
if (this.CurrentDifferenceState == ImageDifference.Previous && this.CurrentRow == 0)
{
this.MoveToNextStateInPreviousNextDifferenceCycle();
}
else if (this.CurrentDifferenceState == ImageDifference.Next && this.CurrentRow == this.Database.CurrentlySelectedFileCount - 1)
{
this.MoveToNextStateInPreviousNextDifferenceCycle();
}
else if (this.CurrentDifferenceState == ImageDifference.Next && !this.Database.IsFileDisplayable(this.CurrentRow + 1))
{
this.MoveToNextStateInPreviousNextDifferenceCycle();
}
else if (this.CurrentDifferenceState == ImageDifference.Previous && !this.Database.IsFileDisplayable(this.CurrentRow - 1))
{
this.MoveToNextStateInPreviousNextDifferenceCycle();
}
}
public void MoveToNextStateInCombinedDifferenceCycle()
{
Debug.Assert((this.Current != null) && (this.Current.IsVideo == false), "No current file or current file is an image.");
// if this method and MoveToNextStateInPreviousNextDifferenceCycle() returned bool they'd be consistent MoveNext() and MovePrevious()
// however, there's no way for them to fail and there's not value in always returning true
if (this.CurrentDifferenceState == ImageDifference.Next ||
this.CurrentDifferenceState == ImageDifference.Previous ||
this.CurrentDifferenceState == ImageDifference.Combined)
{
this.CurrentDifferenceState = ImageDifference.Unaltered;
}
else
{
this.CurrentDifferenceState = ImageDifference.Combined;
}
}
public static JArray Parse(MappedFile file, ImageDifference imageDiff)
{
if (imageDiff.IsLoad)
{
return(new JArray(new JObject
{
["Action"] = "Load",
["Target"] = file.RelativeMappedPath,
["FromFile"] = Path.Combine("assets", file.RelativeFilePath)
}));
}
JArray changes = new JArray();
foreach (Area change in imageDiff.Differences)
{
JObject newToken = new JObject
{
["Action"] = "EditImage",
["Target"] = file.RelativeMappedPath,
["FromFile"] = Path.Combine("assets", file.RelativeFilePath)
};
JObject area = new JObject
{
["X"] = change.Left,
["Y"] = change.Top,
["Width"] = change.Width,
["Height"] = change.Height
};
newToken["FromArea"] = area;
newToken["ToArea"] = area;
changes.Add(newToken);
}
return(changes);
}
private void ResetDifferenceState(BitmapSource unalteredImage)
{
this.CurrentDifferenceState = ImageDifference.Unaltered;
this.differenceBitmapCache[ImageDifference.Unaltered] = unalteredImage;
this.differenceBitmapCache[ImageDifference.Previous] = null;
this.differenceBitmapCache[ImageDifference.Next] = null;
this.differenceBitmapCache[ImageDifference.Combined] = null;
}
public async Task<ImageDifferenceResult> TryCalculateCombinedDifferenceAsync(byte differenceThreshold)
{
if (this.CurrentDifferenceState != ImageDifference.Combined)
{
return ImageDifferenceResult.NotCalculable;
}
// three valid images are needed: the current one, the previous one, and the next one
if (this.Current == null || this.Current.IsVideo || this.Current.IsDisplayable() == false)
{
this.CurrentDifferenceState = ImageDifference.Unaltered;
return ImageDifferenceResult.CurrentImageNotAvailable;
}
WriteableBitmap previousBitmap = await this.TryGetPreviousBitmapAsWriteableAsync();
if (previousBitmap == null)
{
return ImageDifferenceResult.PreviousImageNotAvailable;
}
WriteableBitmap nextBitmap = await this.TryGetNextBitmapAsWriteableAsync();
if (nextBitmap == null)
{
return ImageDifferenceResult.NextImageNotAvailable;
}
BitmapSource unalteredBitmap = this.differenceBitmapCache[ImageDifference.Unaltered];
Debug.Assert(unalteredBitmap != null, "Difference cache coherency error: unaltered bitmap is null.");
WriteableBitmap unalteredWriteableBitmap = unalteredBitmap.AsWriteable();
this.differenceBitmapCache[ImageDifference.Unaltered] = unalteredWriteableBitmap;
// all three images are available, so calculate and cache difference
BitmapSource differenceBitmap = await Task.Run(() => { return unalteredWriteableBitmap.Difference(previousBitmap, nextBitmap, differenceThreshold); });
this.differenceBitmapCache[ImageDifference.Combined] = differenceBitmap;
return differenceBitmap != null ? ImageDifferenceResult.Success : ImageDifferenceResult.NotCalculable;
}
public async Task<ImageDifferenceResult> TryCalculateDifferenceAsync()
{
if (this.Current == null || this.Current.IsVideo || this.Current.IsDisplayable() == false)
{
this.CurrentDifferenceState = ImageDifference.Unaltered;
return ImageDifferenceResult.CurrentImageNotAvailable;
}
// determine which image to use for differencing
WriteableBitmap comparisonBitmap = null;
if (this.CurrentDifferenceState == ImageDifference.Previous)
{
comparisonBitmap = await this.TryGetPreviousBitmapAsWriteableAsync();
if (comparisonBitmap == null)
{
return ImageDifferenceResult.PreviousImageNotAvailable;
}
}
else if (this.CurrentDifferenceState == ImageDifference.Next)
{
comparisonBitmap = await this.TryGetNextBitmapAsWriteableAsync();
if (comparisonBitmap == null)
{
return ImageDifferenceResult.NextImageNotAvailable;
}
}
else
{
return ImageDifferenceResult.NotCalculable;
}
WriteableBitmap unalteredBitmap = this.differenceBitmapCache[ImageDifference.Unaltered].AsWriteable();
this.differenceBitmapCache[ImageDifference.Unaltered] = unalteredBitmap;
BitmapSource differenceBitmap = await Task.Run(() => { return unalteredBitmap.Difference(comparisonBitmap); });
this.differenceBitmapCache[this.CurrentDifferenceState] = differenceBitmap;
return differenceBitmap != null ? ImageDifferenceResult.Success : ImageDifferenceResult.NotCalculable;
}
