From b8b368dc7c73001ac2b039f3d41269bcb359ba24 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Thu, 26 May 2011 16:26:50 +0000
Subject: [PATCH] From Bryce Eldridge, "Here is an update for the TIFF plugin
 that includes the following features when writing out TIFF files:

- Support for writing unsigned 16-bit images (GL_UNSIGNED_SHORT)
- Code to parse the options string for the following options:
-- Flag to turn off the compression. The PACKBITS compression type causes issues for me with some programs on Windows (Picasa for example).
-- Options to set the XRESOLUTION and YRESOLUTION tags (DPI) in the TIFF file.

Existing behavior (PACKBITS compression, DPI tags left at default) is preserved if the options string is not set.
"
---
 src/osgPlugins/tiff/ReaderWriterTIFF.cpp | 46 +++++++++++++++++++++---
 1 file changed, 42 insertions(+), 4 deletions(-)

diff --git a/src/osgPlugins/tiff/ReaderWriterTIFF.cpp b/src/osgPlugins/tiff/ReaderWriterTIFF.cpp
index e463b7825..e210d60fb 100644
--- a/src/osgPlugins/tiff/ReaderWriterTIFF.cpp
+++ b/src/osgPlugins/tiff/ReaderWriterTIFF.cpp
@@ -829,7 +829,7 @@ class ReaderWriterTIFF : public osgDB::ReaderWriter
             return pOsgImage;
         }
 
-        WriteResult::WriteStatus writeTIFStream(std::ostream& fout, const osg::Image& img) const
+        WriteResult::WriteStatus writeTIFStream(std::ostream& fout, const osg::Image& img, bool noCompression, float xResDPI, float yResDPI) const
         {
             //Code is based from the following article on CodeProject.com
             //http://www.codeproject.com/bitmap/BitmapsToTiffs.asp
@@ -887,6 +887,10 @@ class ReaderWriterTIFF : public osgDB::ReaderWriter
                     TIFFSetField(image, TIFFTAG_SAMPLEFORMAT, SAMPLEFORMAT_INT);
                     bitsPerSample = 16;
                     break;
+                case GL_UNSIGNED_SHORT:
+                    TIFFSetField(image, TIFFTAG_SAMPLEFORMAT, SAMPLEFORMAT_UINT);
+                    bitsPerSample = 16;
+                    break;
                 default:
                     bitsPerSample = 8;
                     break;
@@ -897,10 +901,17 @@ class ReaderWriterTIFF : public osgDB::ReaderWriter
             TIFFSetField(image, TIFFTAG_BITSPERSAMPLE,bitsPerSample);
             TIFFSetField(image, TIFFTAG_SAMPLESPERPIXEL,samplesPerPixel);
             TIFFSetField(image, TIFFTAG_PHOTOMETRIC, photometric);
-            TIFFSetField(image, TIFFTAG_COMPRESSION, COMPRESSION_PACKBITS); 
+            TIFFSetField(image, TIFFTAG_COMPRESSION, noCompression ? COMPRESSION_NONE : COMPRESSION_PACKBITS); 
             TIFFSetField(image, TIFFTAG_FILLORDER, FILLORDER_MSB2LSB);
             TIFFSetField(image, TIFFTAG_PLANARCONFIG, PLANARCONFIG_CONTIG);
 
+            if(xResDPI > 0 && yResDPI > 0)
+            {
+                TIFFSetField(image, TIFFTAG_RESOLUTIONUNIT, RESUNIT_INCH);
+                TIFFSetField(image, TIFFTAG_XRESOLUTION, xResDPI);
+                TIFFSetField(image, TIFFTAG_YRESOLUTION, yResDPI);
+            }
+
             //uint32 rowsperstrip = TIFFDefaultStripSize(image, -1); 
             //TIFFSetField(image, TIFFTAG_ROWSPERSTRIP, rowsperstrip);
             
@@ -945,9 +956,36 @@ class ReaderWriterTIFF : public osgDB::ReaderWriter
             return rr;
         }
 
-        virtual WriteResult writeImage(const osg::Image& img,std::ostream& fout,const osgDB::ReaderWriter::Options* /*options*/) const
+        virtual WriteResult writeImage(const osg::Image& img,std::ostream& fout,const osgDB::ReaderWriter::Options* options) const
         {
-            WriteResult::WriteStatus ws = writeTIFStream(fout,img);
+            bool noCompression = false;
+            float xResDPI = 0;
+            float yResDPI = 0;
+
+            if(options)
+            {
+                std::istringstream iss(options->getOptionString());
+                std::string opt;
+
+                while( iss >> opt)
+                {
+                    if(opt == "no_compression")
+                    {
+                        noCompression = true;
+                    }
+                    else if(opt == "x_resolution")
+                    {
+                        iss >> xResDPI;
+                    }
+                    else if(opt == "y_resolution")
+                    {
+                        iss >> yResDPI;
+                    }
+                }
+            }
+
+
+            WriteResult::WriteStatus ws = writeTIFStream(fout,img,noCompression,xResDPI,yResDPI);
             return ws;
         }