# HG changeset patch
# User magedrifaat <magedrifaat@gmail.com>
# Date 1658436241 -7200
# Node ID e8d1cc309bc9373f56ddc2980654c6e20571e5c7
# Parent  0bcb35909ef41e57347585eae6c25e972416d92d
Tiff: added initial implementation of setTag function for scalar tags

* __tiff__.cc(F__tiff_set_tag): Added internal function for setTag.
* __tiff__.cc(set_field_data): Implemented support for scalar tags only.
* Tiff.m(setTag): Added setTag method.

diff -r 0bcb35909ef4 -r e8d1cc309bc9 libinterp/dldfcn/__tiff__.cc
--- a/libinterp/dldfcn/__tiff__.cc	Thu Jul 21 20:03:43 2022 +0200
+++ b/libinterp/dldfcn/__tiff__.cc	Thu Jul 21 22:44:01 2022 +0200
@@ -641,6 +641,7 @@
     
     // TODO(maged): test this function vs actual data type size
     int type_size = TIFFDataWidth (TIFFFieldDataType (fip));
+    // TODO(maged): use shared pointer instead of malloc
     void *data = _TIFFmalloc (type_size);
     validate_tiff_get_field (TIFFGetField (tif, tag_id, data), data);
     octave_value tag_data_ov = interpret_tag_data (data, 1,
@@ -847,6 +848,18 @@
     
     return tag_data_ov;
   }
+
+  void
+  set_field_data (TIFF *tif, const TIFFField *fip, octave_value tag_ov)
+  {
+    // TODO(maged): complete the implementation of this function
+    uint32_t tag_id = TIFFFieldTag (fip);
+    uint32_t tag_data = tag_ov.double_value ();
+
+    if (! TIFFSetField(tif, tag_id, tag_data))
+      error ("Failed to set tag value");
+  }
+
 #endif
 
   DEFUN_DLD (__open_tiff__, args, nargout,
@@ -951,6 +964,52 @@
 #endif
   }
 
+
+  DEFUN_DLD (__tiff_set_tag__, args, nargout,
+             "Set the value of a tag in a tiff image")
+  {
+#if defined (HAVE_TIFF)
+    int nargin = args.length ();
+    
+    if (nargin < 2)
+      error ("Too few arguments provided\n");
+    
+    TIFF *tif = (TIFF *)(args (0).uint64_value ());
+    
+    // TODO(maged): does matlab allow calling this function for images
+    // opened for reading?
+    if (args (1).type_name () == "struct")
+      error ("setTag with struct is not yet supported");
+    else
+      {
+        const TIFFField *fip;
+        if (args (1).type_name () == "string")
+          {
+            std::string tagName = args (1).string_value ();
+            fip = TIFFFieldWithName (tif, tagName.c_str ());
+            if (! fip)
+              error ("Tiff tag not found");
+          }
+        else
+          {
+            uint32_t tag_id = args (1).int_value ();
+            fip = TIFFFieldWithTag (tif, tag_id);
+            if (! fip)
+              error ("Tiff tag not found");
+          }
+        
+        if (nargin < 3)
+          error ("Too few arguments provided");
+        
+        set_field_data (tif, fip, args (2));
+      }
+
+    return octave_value_list ();
+#else
+    err_disabled_feature ("setTag", "Tiff");
+#endif
+  }
+
   DEFUN_DLD (__tiff_read__, args, nargout,
              "Read the image in the current IFD")
   {
diff -r 0bcb35909ef4 -r e8d1cc309bc9 scripts/io/Tiff.m
--- a/scripts/io/Tiff.m	Thu Jul 21 20:03:43 2022 +0200
+++ b/scripts/io/Tiff.m	Thu Jul 21 22:44:01 2022 +0200
@@ -92,8 +92,12 @@
             __close_tiff__(t.tiff_handle);
         endfunction
 
-        function tag = getTag(t, tagName)
-            tag = __tiff_get_tag__(t.tiff_handle, tagName);
+        function tag = getTag(t, tag_name)
+            tag = __tiff_get_tag__(t.tiff_handle, tag_name);
+        endfunction
+
+        function setTag(t, tag_name, tag_value)
+            __tiff_set_tag__(t.tiff_handle, tag_name, tag_value);
         endfunction
 
         function argout = read(t)