Create a Bigtiff (>4GB) File with Bitmiracle Libtiff.net

问题

First I want to thank Bitmiracle for this great lib. Even while creating very big files, the memory footprint is very low. A few days ago I ran into a problem where I wanted to create a tiff file bigger than 4GB. I created the tiled tiff file successfully, but it seems that the color of the tiles created beyond 4GB are somehow inverted.

Here the code relevant code:

Usage:

WriteTiledTiff("bigtiff.tiff",BitmapSourceFromBrush(new RadialGradientBrush(Colors.Aqua,Colors.Red), 256));

Methods:

public static BitmapSource BitmapSourceFromBrush(Brush drawingBrush, int size = 32, int dpi = 96)
    {
        // RenderTargetBitmap = builds a bitmap rendering of a visual
        var pixelFormat = PixelFormats.Pbgra32;
        RenderTargetBitmap rtb = new RenderTargetBitmap(size, size, dpi, dpi, pixelFormat);

        // Drawing visual allows us to compose graphic drawing parts into a visual to render
        var drawingVisual = new DrawingVisual();
        using (DrawingContext context = drawingVisual.RenderOpen())
        {
            // Declaring drawing a rectangle using the input brush to fill up the visual
            context.DrawRectangle(drawingBrush, null, new Rect(0, 0, size, size));
        }

        // Actually rendering the bitmap
        rtb.Render(drawingVisual);
        return rtb;
    }

public static void WriteTiledTiff(string fileName, BitmapSource tile)
    {
        const int PIXEL_WIDTH = 48000;
        const int PIXEL_HEIGHT = 48000;

         int iTile_Width = tile.PixelWidth;
         int iTile_Height = tile.PixelHeight;

        using (Tiff tiff = Tiff.Open(fileName, "w"))
        {
            tiff.SetField(TiffTag.IMAGEWIDTH, PIXEL_WIDTH);
            tiff.SetField(TiffTag.IMAGELENGTH, PIXEL_HEIGHT);
            tiff.SetField(TiffTag.COMPRESSION, Compression.NONE);
            tiff.SetField(TiffTag.PHOTOMETRIC, Photometric.RGB);

            tiff.SetField(TiffTag.ROWSPERSTRIP, PIXEL_HEIGHT);

            tiff.SetField(TiffTag.XRESOLUTION, 96);
            tiff.SetField(TiffTag.YRESOLUTION, 96);

            tiff.SetField(TiffTag.BITSPERSAMPLE, 8);
            tiff.SetField(TiffTag.SAMPLESPERPIXEL, 3);

            tiff.SetField(TiffTag.PLANARCONFIG, PlanarConfig.CONTIG);

            tiff.SetField(TiffTag.TILEWIDTH, iTile_Width);
            tiff.SetField(TiffTag.TILELENGTH, iTile_Height);

            int tileC = 0;
            for (int row = 0; row < PIXEL_HEIGHT; row += iTile_Height)
            {
                for (int col = 0; col < PIXEL_WIDTH; col += iTile_Width)
                {
                    if (tile.Format != PixelFormats.Rgb24) tile = new FormatConvertedBitmap(tile, PixelFormats.Rgb24, null, 0);
                    int stride = tile.PixelWidth * ((tile.Format.BitsPerPixel + 7) / 8);

                    byte[] pixels = new byte[tile.PixelHeight * stride];
                    tile.CopyPixels(pixels, stride, 0);

                    tiff.WriteEncodedTile(tileC++, pixels, pixels.Length);
                }
            }

            tiff.WriteDirectory();
        }
    }

The resulted file will be 6,47GB in size. I viewed it with a small tool called "vliv" vilv download

回答1:

All LibTiff.Net versions including 2.4.500.0 are based on 3.x branch of the original libtiff.

Support for BigTIFF was introduced in 4.x branch of the original libtiff. Thus, at this time there are no LibTiff.Net versions designed to handle BigTiff files / files over 4GB on disk.

EDIT:

LibTiff.Net 2.4.508 adds support for BigTiff.

回答2:

I don't have enough reputation to comment, so I'm posting this as an answer even if it does not answer the original question.

@Andreas asked in a comment

Is there a possibility to force "bigtiff" even when the size is smaller than 4gb?

and indeed there is. The trick is to pass an additional '8' to the mode parameter of the Tiff.Open method:

using (Tiff output = Tiff.Open(filePath, "w8"))

The mode parameter is described here about after the first third of the page

回答3:

I downloaded the Milster repo https://github.com/Milster/libtiff.net and builded the BitMiracle.LibTiff.NET.dll myself. This worked for me!

EDIT: V. 2.4.528 worked also for me!

来源：https://stackoverflow.com/questions/28676738/create-a-bigtiff-4gb-file-with-bitmiracle-libtiff-net

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