コード例 #1
0
        /// <summary>
        /// Decodes the raw pixel data row by row
        /// </summary>
        /// <typeparam name="TPixel">The pixel format.</typeparam>
        /// <param name="compressedStream">The compressed pixel data stream.</param>
        /// <param name="image">The image to decode to.</param>
        private void DecodePixelData <TPixel>(Stream compressedStream, ImageFrame <TPixel> image)
            where TPixel : struct, IPixel <TPixel>
        {
            while (this.currentRow < this.header.Height)
            {
                int bytesRead = compressedStream.Read(this.scanline.Array, this.currentRowBytesRead, this.bytesPerScanline - this.currentRowBytesRead);
                this.currentRowBytesRead += bytesRead;
                if (this.currentRowBytesRead < this.bytesPerScanline)
                {
                    return;
                }

                this.currentRowBytesRead = 0;
                var filterType = (FilterType)this.scanline[0];

                switch (filterType)
                {
                case FilterType.None:
                    break;

                case FilterType.Sub:

                    SubFilter.Decode(this.scanline, this.bytesPerPixel);
                    break;

                case FilterType.Up:

                    UpFilter.Decode(this.scanline, this.previousScanline);
                    break;

                case FilterType.Average:

                    AverageFilter.Decode(this.scanline, this.previousScanline, this.bytesPerPixel);
                    break;

                case FilterType.Paeth:

                    PaethFilter.Decode(this.scanline, this.previousScanline, this.bytesPerPixel);
                    break;

                default:
                    throw new ImageFormatException("Unknown filter type.");
                }

                this.ProcessDefilteredScanline(this.scanline.Array, image);

                Swap(ref this.scanline, ref this.previousScanline);
                this.currentRow++;
            }
        }
コード例 #2
0
        private void DecodePixelData(byte[][] pixelData)
        {
//            data = new Color[_width * _height];
            _colors = new Color[width * height];
            pixels  = new int[width * height];

            var previousScanline = new byte[bytesPerScanline];

            for (var y = 0; y < height; ++y)
            {
                var    scanline = pixelData[y];
                byte[] defilteredScanline;
                switch (scanline[0])
                {
                case 0:
                    defilteredScanline = NoneFilter.Decode(scanline);
                    break;

                case 1:
                    defilteredScanline = SubFilter.Decode(scanline, bytesPerPixel);
                    break;

                case 2:
                    defilteredScanline = UpFilter.Decode(scanline, previousScanline);
                    break;

                case 3:
                    defilteredScanline = AverageFilter.Decode(scanline, previousScanline, bytesPerPixel);
                    break;

                case 4:
                    defilteredScanline = PaethFilter.Decode(scanline, previousScanline, bytesPerPixel);
                    break;

                default:
                    throw new Exception("Unknown filter type.");
                }

                previousScanline = defilteredScanline;
                ProcessDefilteredScanline(defilteredScanline, y);
            }
        }
コード例 #3
0
        /// <summary>
        /// Decodes the raw interlaced pixel data row by row
        /// <see href="https://github.com/juehv/DentalImageViewer/blob/8a1a4424b15d6cc453b5de3f273daf3ff5e3a90d/DentalImageViewer/lib/jiu-0.14.3/net/sourceforge/jiu/codecs/PNGCodec.java"/>
        /// </summary>
        /// <typeparam name="TPixel">The pixel format.</typeparam>
        /// <param name="compressedStream">The compressed pixel data stream.</param>
        /// <param name="image">The current image.</param>
        private void DecodeInterlacedPixelData <TPixel>(Stream compressedStream, ImageFrame <TPixel> image)
            where TPixel : struct, IPixel <TPixel>
        {
            while (true)
            {
                int numColumns = this.ComputeColumnsAdam7(this.pass);

                if (numColumns == 0)
                {
                    this.pass++;

                    // This pass contains no data; skip to next pass
                    continue;
                }

                int bytesPerInterlaceScanline = this.CalculateScanlineLength(numColumns) + 1;

                while (this.currentRow < this.header.Height)
                {
                    int bytesRead = compressedStream.Read(this.scanline.Array, this.currentRowBytesRead, bytesPerInterlaceScanline - this.currentRowBytesRead);
                    this.currentRowBytesRead += bytesRead;
                    if (this.currentRowBytesRead < bytesPerInterlaceScanline)
                    {
                        return;
                    }

                    this.currentRowBytesRead = 0;

                    Span <byte> scanSpan   = this.scanline.Slice(0, bytesPerInterlaceScanline);
                    Span <byte> prevSpan   = this.previousScanline.Slice(0, bytesPerInterlaceScanline);
                    var         filterType = (FilterType)scanSpan[0];

                    switch (filterType)
                    {
                    case FilterType.None:
                        break;

                    case FilterType.Sub:

                        SubFilter.Decode(scanSpan, this.bytesPerPixel);
                        break;

                    case FilterType.Up:

                        UpFilter.Decode(scanSpan, prevSpan);
                        break;

                    case FilterType.Average:

                        AverageFilter.Decode(scanSpan, prevSpan, this.bytesPerPixel);
                        break;

                    case FilterType.Paeth:

                        PaethFilter.Decode(scanSpan, prevSpan, this.bytesPerPixel);
                        break;

                    default:
                        throw new ImageFormatException("Unknown filter type.");
                    }

                    Span <TPixel> rowSpan = image.GetPixelRowSpan(this.currentRow);
                    this.ProcessInterlacedDefilteredScanline(this.scanline.Array, rowSpan, Adam7FirstColumn[this.pass], Adam7ColumnIncrement[this.pass]);

                    Swap(ref this.scanline, ref this.previousScanline);

                    this.currentRow += Adam7RowIncrement[this.pass];
                }

                this.pass++;
                this.previousScanline.Clear();

                if (this.pass < 7)
                {
                    this.currentRow = Adam7FirstRow[this.pass];
                }
                else
                {
                    this.pass = 0;
                    break;
                }
            }
        }