C# CroppedBitmap.BeginInit方法代码示例

 public CroppedBitmap GetBitMap(int id)
 {
     var p = GetPosition(id);
     var bitmap = new CroppedBitmap();
     bitmap.BeginInit();
     bitmap.Source = _imageSource;
     bitmap.SourceRect = new Int32Rect(p.X * _cropSize, p.Y * _cropSize, _cropSize, _cropSize);
     bitmap.EndInit();
     return bitmap;
 }

            public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
            {
                CroppedBitmap cb = new CroppedBitmap();
                cb.BeginInit();
                cb.Source = (BitmapSource)value;

                cb.SourceRect = new Int32Rect(int.Parse(parameter.ToString()), 0, 256, 256);
                cb.EndInit();
                return new ImageBrush((ImageSource)cb);
                //return (ImageSource)cb;
            }

//.........这里部分代码省略.........
                else
                { 
                    Debug.Assert(decoder.SyncObject != null); 
                }
            } 
            else
            {
                // We already had a decoder, meaning we were downloading
                Debug.Assert(!_decoder.IsDownloading); 
                decoder = _decoder;
                _decoder = null; 
            } 

            if (decoder.Frames.Count == 0) 
            {
                throw new System.ArgumentException(SR.Get(SRID.Image_NoDecodeFrames));
            }
 
            BitmapFrame frame = decoder.Frames[0];
            BitmapSource source = frame; 
 
            Int32Rect sourceRect = SourceRect;
 
            if (sourceRect.X == 0 && sourceRect.Y == 0 &&
                sourceRect.Width == source.PixelWidth &&
                sourceRect.Height == source.PixelHeight)
            { 
                sourceRect = Int32Rect.Empty;
            } 
 
            if (!sourceRect.IsEmpty)
            { 
                CroppedBitmap croppedSource = new CroppedBitmap();
                croppedSource.BeginInit();
                croppedSource.Source = source;
                croppedSource.SourceRect = sourceRect; 
                croppedSource.EndInit();
 
                source = croppedSource; 
                if (_isDownloading)
                { 
                    // Unregister the download events because this is a dummy image. See comment below.
                    source.UnregisterDownloadEventSource();
                }
            } 

            int finalWidth = DecodePixelWidth; 
            int finalHeight = DecodePixelHeight; 

            if (finalWidth == 0 && finalHeight == 0) 
            {
                finalWidth = source.PixelWidth;
                finalHeight = source.PixelHeight;
            } 
            else if (finalWidth == 0)
            { 
                finalWidth = (source.PixelWidth * finalHeight) / source.PixelHeight; 
            }
            else if (finalHeight == 0) 
            {
                finalHeight = (source.PixelHeight * finalWidth) / source.PixelWidth;
            }
 
            if (finalWidth != source.PixelWidth || finalHeight != source.PixelHeight ||
                Rotation != Rotation.Rotate0) 
            { 

        protected CroppedBitmap[] GetSpriteSources(String source, Int32 rows, Int32 columns)
        {
            var sourceImage = ImageUtility.InitializeBitmapSourceFromLocation(source);

            var sourceWidth = sourceImage.PixelWidth / columns;
            var sourceHeight = sourceImage.PixelHeight / rows;

            var sources = new CroppedBitmap[rows * columns];
            for (Int32 index = 0; index < sources.Count(); index++)
            {
                var xPosition = (index % columns) * sourceWidth;
                var yPosition = (index / columns) * sourceHeight;

                var croppedBitmap = new CroppedBitmap();
                croppedBitmap.BeginInit();
                croppedBitmap.Source = sourceImage;
                croppedBitmap.SourceRect = new Int32Rect(xPosition, yPosition, sourceWidth, sourceHeight);
                croppedBitmap.EndInit();
                sources[index] = croppedBitmap;
            }

            return sources;
        }

        /// <summary>
        /// When implemented in a derived class, returns an object that is provided as the value of
        /// the target property for this markup extension.
        /// </summary>
        /// <param name="serviceProvider">
        /// A service provider helper that can provide services for the markup extension.
        /// </param>
        /// <returns>
        /// The object value to set on the property where the extension is applied.
        /// </returns>
        public override object ProvideValue(IServiceProvider serviceProvider)
        {
            // Setting BitmapImage.SourceRect has no effect. Need to use CroppedBitmap.
            if (WindowsHelper.IsInDesignMode)
            {
                // ----- Design time:
                // Design mode requires special code when used inside a WPF styles.
                var bitmapImage = Source as BitmapImage;
                if (bitmapImage == null)
                    return null;

                var croppedBitmap = new CroppedBitmap();
                croppedBitmap.BeginInit();
                croppedBitmap.Source = new BitmapImage(bitmapImage.UriSource);
                croppedBitmap.SourceRect = SourceRect;
                croppedBitmap.EndInit();
                croppedBitmap.Freeze();

                return croppedBitmap;
            }
            else
            {
                // ----- Run time:
                var bitmapSource = Source as BitmapSource;
                if (bitmapSource == null)
                    return null;

                // Freeze bitmap for performance.
                bitmapSource.Freeze();

                var croppedBitmap = new CroppedBitmap(bitmapSource, SourceRect);
                croppedBitmap.Freeze();

                return croppedBitmap;
            }
        }

        /// <summary>
        /// Get one cell from sprite sheet
        /// </summary>
        /// <param name="sSpriteSheet">Filename of sprite sheet</param>
        /// <returns>Cropped image as a new CroppedBitmap</returns>
        public CroppedBitmap GetCell(string sSpriteSheet,int iStartX,int iStartY,int iEndX,int iEndY)
        {
            Image iWhichSpriteSheet;
            dSpriteSheets.TryGetValue(sSpriteSheet, out iWhichSpriteSheet);

            CroppedBitmap cbNew = new CroppedBitmap();
            cbNew.BeginInit();
            cbNew.Source = (BitmapSource)iWhichSpriteSheet.Source;
            cbNew.SourceRect = new Int32Rect(iStartX,iStartY,iEndX,iEndY);
            cbNew.EndInit();

            return cbNew;
        }

		private static void UpdateCornerImage(Image image, Grid imageHolder, BitmapSource bitmap, RegionChooser regionChooser, bool isRetry = false)
		{
			// Image dimensions
			int imageWidth = bitmap.PixelWidth;
			int imageHeight = bitmap.PixelHeight;

			double availableWidth = imageHolder.ActualWidth;
			double availableHeight = imageHolder.ActualHeight;

			if (availableWidth == 0 || availableHeight == 0)
			{
				// Intermittent bug causing this. In this case we queue it up to go again after a layout pass has been done.
				if (!isRetry)
				{
					DispatchService.BeginInvoke(() =>
						{
							UpdateCornerImage(image, imageHolder, bitmap, regionChooser, isRetry: true);
						});
				}

				return;
			}

			int cornerWidthPixels = (int)(availableWidth / ZoomedPixelSize);
			int cornerHeightPixels = (int)(availableHeight / ZoomedPixelSize);

			// Make sure the subsection of the image is not larger than the image itself
			cornerWidthPixels = Math.Min(cornerWidthPixels, imageWidth);
			cornerHeightPixels = Math.Min(cornerHeightPixels, imageHeight);

			double cornerWidth = cornerWidthPixels * ZoomedPixelSize;
			double cornerHeight = cornerHeightPixels * ZoomedPixelSize;

			var croppedBitmap = new CroppedBitmap();
			croppedBitmap.BeginInit();
			croppedBitmap.SourceRect = regionChooser(imageWidth, imageHeight, cornerWidthPixels, cornerHeightPixels);
			croppedBitmap.Source = bitmap;
			croppedBitmap.EndInit();

			image.Source = croppedBitmap;
			image.Width = cornerWidth;
			image.Height = cornerHeight;
		}