From 81384baf080d869dadbebffa117fb9f6794b363c Mon Sep 17 00:00:00 2001
From: David Rose <david@ddrose.com>
Date: Fri, 3 Feb 2012 22:58:16 +0000
Subject: [PATCH] don't write blue images for grayscale bmp files

---
 panda/src/pnmimage/pnmImage.cxx                  |  9 +++++++++
 panda/src/pnmimage/pnmWriter.cxx                 | 15 +++++++++++++++
 panda/src/pnmimage/pnmWriter.h                   |  1 +
 panda/src/pnmimagetypes/pnmFileTypeBMP.h         |  1 +
 panda/src/pnmimagetypes/pnmFileTypeBMPWriter.cxx | 15 +++++++++++++++
 5 files changed, 41 insertions(+)

diff --git a/panda/src/pnmimage/pnmImage.cxx b/panda/src/pnmimage/pnmImage.cxx
index a6c755fb5f..9638bfa824 100644
--- a/panda/src/pnmimage/pnmImage.cxx
+++ b/panda/src/pnmimage/pnmImage.cxx
@@ -400,6 +400,15 @@ write(PNMWriter *writer) const {
   }
 
   writer->copy_header_from(*this);
+  if (is_grayscale() && !writer->supports_grayscale()) {
+    // Copy the gray values to all channels to help out the writer.
+    for (int y = 0; y < get_y_size(); y++) {
+      for (int x = 0; x<get_x_size(); x++) {
+        ((PNMImage *)this)->set_xel_val(x, y, get_gray_val(x, y));
+      }
+    }
+  }
+
   int result = writer->write_data(_array, _alpha);
   delete writer;
 
diff --git a/panda/src/pnmimage/pnmWriter.cxx b/panda/src/pnmimage/pnmWriter.cxx
index 52d47c0607..a921572b66 100644
--- a/panda/src/pnmimage/pnmWriter.cxx
+++ b/panda/src/pnmimage/pnmWriter.cxx
@@ -86,6 +86,21 @@ supports_write_row() const {
   return false;
 }
 
+////////////////////////////////////////////////////////////////////
+//     Function: PNMWriter::supports_grayscale
+//       Access: Public, Virtual
+//  Description: Returns true if this particular PNMWriter understands
+//               grayscale images.  If this is false, then the rgb
+//               values of the xel array will be pre-filled with the
+//               same value across all three channels, to allow the
+//               writer to simply write out RGB data for a grayscale
+//               image.
+////////////////////////////////////////////////////////////////////
+bool PNMWriter::
+supports_grayscale() const {
+  return true;
+}
+
 ////////////////////////////////////////////////////////////////////
 //     Function: PNMWriter::write_header
 //       Access: Public, Virtual
diff --git a/panda/src/pnmimage/pnmWriter.h b/panda/src/pnmimage/pnmWriter.h
index 3649b6d022..732c1bd367 100644
--- a/panda/src/pnmimage/pnmWriter.h
+++ b/panda/src/pnmimage/pnmWriter.h
@@ -50,6 +50,7 @@ public:
 
   virtual int write_data(xel *array, xelval *alpha);
   virtual bool supports_write_row() const;
+  virtual bool supports_grayscale() const;
   virtual bool write_header();
   virtual bool write_row(xel *array, xelval *alpha);
 
diff --git a/panda/src/pnmimagetypes/pnmFileTypeBMP.h b/panda/src/pnmimagetypes/pnmFileTypeBMP.h
index d57df31dd7..e6fc3b84d0 100644
--- a/panda/src/pnmimagetypes/pnmFileTypeBMP.h
+++ b/panda/src/pnmimagetypes/pnmFileTypeBMP.h
@@ -70,6 +70,7 @@ public:
     Writer(PNMFileType *type, ostream *file, bool owns_file);
 
     virtual int write_data(xel *array, xelval *alpha);
+    virtual bool supports_grayscale() const;
   };
 
 
diff --git a/panda/src/pnmimagetypes/pnmFileTypeBMPWriter.cxx b/panda/src/pnmimagetypes/pnmFileTypeBMPWriter.cxx
index 22a9f35f57..4dabd297a7 100644
--- a/panda/src/pnmimagetypes/pnmFileTypeBMPWriter.cxx
+++ b/panda/src/pnmimagetypes/pnmFileTypeBMPWriter.cxx
@@ -634,4 +634,19 @@ write_data(xel *array, xelval *) {
   return _y_size;
 }
 
+////////////////////////////////////////////////////////////////////
+//     Function: PNMFileTypeBMP::Writer::supports_grayscale
+//       Access: Public, Virtual
+//  Description: Returns true if this particular PNMWriter understands
+//               grayscale images.  If this is false, then the rgb
+//               values of the xel array will be pre-filled with the
+//               same value across all three channels, to allow the
+//               writer to simply write out RGB data for a grayscale
+//               image.
+////////////////////////////////////////////////////////////////////
+bool PNMFileTypeBMP::Writer::
+supports_grayscale() const {
+  return false;
+}
+
 #endif  // HAVE_BMP