/// <summary>
/// 引数PATHをサムネイルとして読み出す
/// </summary>
/// <param name="imagePath">ファイルパス</param>
/// <param name="width">サムネイルの画像幅</param>
/// <returns></returns>
public static BitmapSource LoadThumbnail(this string imagePath, int width = DefaultThumbnailWidth)
{
if (imagePath is null)
{
throw new ArgumentNullException(nameof(imagePath));
}
if (!File.Exists(imagePath))
{
throw new FileNotFoundException(imagePath);
}
using (var stream = File.Open(imagePath, FileMode.Open, FileAccess.Read, FileShare.Read))
{
BitmapSource bitmapSource = null;
var img = BitmapFrame.Create(stream, BitmapCreateOptions.None, BitmapCacheOption.None);
if (img.Thumbnail != null)
{
bitmapSource = img.Thumbnail; // サムネイル読み出し高速化
}
else
{
bitmapSource = img as BitmapSource;
}
var longSide = Math.Max(bitmapSource.PixelWidth, bitmapSource.PixelHeight);
var scale = width / (double)longSide;
var thumbnail = new TransformedBitmap(bitmapSource, new ScaleTransform(scale, scale));
var cachedBitmap = new CachedBitmap(thumbnail, BitmapCreateOptions.None, BitmapCacheOption.OnLoad);
cachedBitmap.Freeze();
return((BitmapSource)cachedBitmap); // アップキャストは常に合法
}
}
private static BitmapSource ClearArea(BitmapSource frame, FrameMetadata metadata)
{
DrawingVisual visual = new DrawingVisual();
using (var context = visual.RenderOpen())
{
var fullRect = new Rect(0, 0, frame.PixelWidth, frame.PixelHeight);
var clearRect = new Rect(metadata.Left, metadata.Top, metadata.Width, metadata.Height);
var clip = Geometry.Combine(
new RectangleGeometry(fullRect),
new RectangleGeometry(clearRect),
GeometryCombineMode.Exclude,
null);
context.PushClip(clip);
context.DrawImage(frame, fullRect);
}
var bitmap = new RenderTargetBitmap(
frame.PixelWidth, frame.PixelHeight,
frame.DpiX, frame.DpiY,
PixelFormats.Pbgra32);
bitmap.Render(visual);
var result = new CachedBitmap(bitmap, BitmapCreateOptions.None, BitmapCacheOption.Default);
if (result.CanFreeze && !result.IsFrozen)
{
result.Freeze();
}
return(result);
}
/// <summary>
/// 画像のStreamから埋め込みサムネイル優先でBitmapSourceを作成する
/// </summary>
/// <param name="stream"></param>
/// <param name="widthMax">埋め込みサムネイルが存在しなかった場合に、主画像をリサイズする最大幅</param>
/// <returns></returns>
private static BitmapSource ToBitmapSourceFromEmbeddedThumbnail(this Stream stream, double widthMax)
{
if (stream is null)
{
throw new ArgumentNullException(nameof(stream));
}
var image = BitmapFrame.Create(stream, BitmapCreateOptions.None, BitmapCacheOption.None);
BitmapSource bitmap;
if (image.Thumbnail != null)
{
bitmap = image.Thumbnail;
}
else
{
var longSide = Math.Max(image.PixelWidth, image.PixelHeight);
if (longSide == 0)
{
throw new DivideByZeroException(nameof(longSide));
}
var scale = widthMax / (double)longSide;
var thumbnail = new TransformedBitmap(image, new ScaleTransform(scale, scale));
var cache = new CachedBitmap(thumbnail, BitmapCreateOptions.None, BitmapCacheOption.OnLoad);
cache.Freeze();
bitmap = (BitmapSource)cache; // アップキャストは常に合法
}
return(bitmap);
}
public System.Windows.Media.Imaging.BitmapSource GetThumbnail(int width, int height)
{
BitmapSource thumb = null;
// Try to read the thumbnail.
if (Frame.Thumbnail != null)
{
try
{
double scale;
scale = (Math.Min(width / (double)Frame.Thumbnail.PixelWidth, height / (double)Frame.Thumbnail.PixelHeight));
thumb = Scale(Frame.Thumbnail, scale);
}
catch { if (thumb != null)
{
thumb = null;
}
}
}
// Try to read the preview.
if (thumb == null && Frame.Decoder?.Preview != null)
{
try
{
double scale;
var preview = Frame.Decoder.Preview;
scale = (Math.Min(width / (double)preview.PixelWidth, height / (double)preview.PixelHeight));
thumb = Scale(preview, scale);
}
catch { if (thumb != null)
{
thumb = null;
}
}
}
if (thumb == null)
{
double scale;
scale = (Math.Min(width / (double)Frame.PixelWidth, height / (double)Frame.PixelHeight));
thumb = Scale(Frame, scale);
}
var retval = new CachedBitmap(thumb, BitmapCreateOptions.None, BitmapCacheOption.Default);
retval.Freeze();
return(retval);
}
/// <summary>
/// 引数PATHをサムネイルとして読み出す
/// </summary>
/// <param name="imagePath">ファイルパス</param>
/// <param name="widthMax">サムネイルの画像幅</param>
/// <returns></returns>
public static BitmapSource?ToBitmapSourceThumbnail(this string imagePath, double widthMax)
{
if (!File.Exists(imagePath))
{
return(null); //throw new FileNotFoundException(imagePath);
}
using var stream = File.Open(imagePath, FileMode.Open, FileAccess.Read, FileShare.Read);
var img = BitmapFrame.Create(stream, BitmapCreateOptions.None, BitmapCacheOption.None);
var bitmapSource = img.Thumbnail ?? (img as BitmapSource);
var longSide = Math.Max(bitmapSource.PixelWidth, bitmapSource.PixelHeight);
var scale = widthMax / (double)longSide;
var thumbnail = new TransformedBitmap(bitmapSource, new ScaleTransform(scale, scale));
var cachedBitmap = new CachedBitmap(thumbnail, BitmapCreateOptions.None, BitmapCacheOption.OnLoad);
cachedBitmap.Freeze();
return((BitmapSource)cachedBitmap); // アップキャストは常に合法
}
private static BitmapSource MakeFrame(
Int32Size fullSize,
BitmapSource rawFrame, FrameMetadata metadata,
BitmapSource baseFrame)
{
if (baseFrame == null && IsFullFrame(metadata, fullSize))
{
// No previous image to combine with, and same size as the full image
// Just return the frame as is
return(rawFrame);
}
DrawingVisual visual = new DrawingVisual();
using (var context = visual.RenderOpen())
{
if (baseFrame != null)
{
var fullRect = new Rect(0, 0, fullSize.Width, fullSize.Height);
context.DrawImage(baseFrame, fullRect);
}
var rect = new Rect(metadata.Left, metadata.Top, metadata.Width, metadata.Height);
context.DrawImage(rawFrame, rect);
}
var bitmap = new RenderTargetBitmap(
fullSize.Width, fullSize.Height,
96, 96,
PixelFormats.Pbgra32);
bitmap.Render(visual);
var result = new CachedBitmap(bitmap, BitmapCreateOptions.None, BitmapCacheOption.Default);
if (result.CanFreeze && !result.IsFrozen)
{
result.Freeze();
}
return(result);
}