diff --git a/ChangeLog b/ChangeLog
index 69c4ec328b..c256c44d56 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,20 @@
+2003-07-01  Sven Neumann  <sven@gimp.org>
+
+	* libgimp/gimp.[ch]
+	* libgimp/gimpchannel.[ch]
+	* libgimp/gimpdrawable.[ch]
+	* libgimp/gimpimage.[ch]
+	* libgimp/gimplayer.[ch]
+	* libgimp/gimpmisc.[ch]
+	* libgimp/gimpmiscui.[ch]
+	* libgimp/gimppixelrgn.[ch]
+	* libgimp/gimpproceduraldb.[ch]: added const qualifiers to the
+	libgimp API. Will cause lots of compiler warnings until the
+	generated PDB code has been constified as well.
+
+	* libgimpbase/gimpparasite.[ch]: use gconstpointer, not const
+	gpointer.
+
 2003-07-01  Sven Neumann  <sven@gimp.org>
 
 	* plug-ins/common/ripple.c (average_four_pixels): fixed the
diff --git a/libgimp/gimp.c b/libgimp/gimp.c
index 9b69594838..c4b6f43e3f 100644
--- a/libgimp/gimp.c
+++ b/libgimp/gimp.c
@@ -485,19 +485,19 @@ gimp_quit (void)
  * that will be automatically started on each GIMP startup.
  **/
 void
-gimp_install_procedure (const gchar     *name,
-			const gchar     *blurb,
-			const gchar     *help,
-			const gchar     *author,
-			const gchar     *copyright,
-			const gchar     *date,
-			const gchar     *menu_path,
-			const gchar     *image_types,
-			GimpPDBProcType  type,
-			gint             n_params,
-			gint             n_return_vals,
-			GimpParamDef    *params,
-			GimpParamDef    *return_vals)
+gimp_install_procedure (const gchar        *name,
+			const gchar        *blurb,
+			const gchar        *help,
+			const gchar        *author,
+			const gchar        *copyright,
+			const gchar        *date,
+			const gchar        *menu_path,
+			const gchar        *image_types,
+			GimpPDBProcType     type,
+			gint                n_params,
+			gint                n_return_vals,
+			const GimpParamDef *params,
+			const GimpParamDef *return_vals)
 {
   GPProcInstall proc_install;
 
@@ -566,20 +566,20 @@ gimp_install_procedure (const gchar     *name,
  * details.
  **/
 void
-gimp_install_temp_proc (const gchar     *name,
-			const gchar     *blurb,
-			const gchar     *help,
-			const gchar     *author,
-			const gchar     *copyright,
-			const gchar     *date,
-			const gchar     *menu_path,
-			const gchar     *image_types,
-			GimpPDBProcType  type,
-			gint             n_params,
-			gint             n_return_vals,
-			GimpParamDef    *params,
-			GimpParamDef    *return_vals,
-			GimpRunProc      run_proc)
+gimp_install_temp_proc (const gchar        *name,
+			const gchar        *blurb,
+			const gchar        *help,
+			const gchar        *author,
+			const gchar        *copyright,
+			const gchar        *date,
+			const gchar        *menu_path,
+			const gchar        *image_types,
+			GimpPDBProcType     type,
+			gint                n_params,
+			gint                n_return_vals,
+			const GimpParamDef *params,
+			const GimpParamDef *return_vals,
+			GimpRunProc         run_proc)
 {
   g_return_if_fail (name != NULL);
   g_return_if_fail ((n_params == 0 && params == NULL) ||
@@ -869,10 +869,10 @@ gimp_read_expect_msg (WireMessage *msg,
  * Return value: the procedure's return values.
  **/
 GimpParam *
-gimp_run_procedure2 (const gchar *name,
-		     gint        *n_return_vals,
-		     gint         n_params,
-		     GimpParam   *params)
+gimp_run_procedure2 (const gchar     *name,
+		     gint            *n_return_vals,
+		     gint             n_params,
+		     const GimpParam *params)
 {
   GPProcRun     proc_run;
   GPProcReturn *proc_return;
@@ -1235,10 +1235,10 @@ gimp_extension_process (guint timeout)
  * See Also: gimp_parasite_attach()
  */
 void
-gimp_attach_new_parasite (const gchar    *name, 
-			  gint            flags,
-			  gint            size, 
-			  const gpointer  data)
+gimp_attach_new_parasite (const gchar   *name,
+			  gint           flags,
+			  gint           size, 
+			  gconstpointer  data)
 {
   GimpParasite *parasite = gimp_parasite_new (name, flags, size, data);
 
diff --git a/libgimp/gimp.h b/libgimp/gimp.h
index 2495c039ba..f4b175b67a 100644
--- a/libgimp/gimp.h
+++ b/libgimp/gimp.h
@@ -74,11 +74,11 @@ GIMPVAR const guint gimp_micro_version;
 typedef void (* GimpInitProc)  (void);
 typedef void (* GimpQuitProc)  (void);
 typedef void (* GimpQueryProc) (void);
-typedef void (* GimpRunProc)   (gchar      *name,
-				gint        nparams,
-				GimpParam  *param,
-				gint       *nreturn_vals,
-				GimpParam **return_vals);
+typedef void (* GimpRunProc)   (const gchar      *name,
+				gint              n_params,
+				const GimpParam  *param,
+				gint             *n_return_vals,
+				GimpParam       **return_vals);
 
 
 struct _GimpPlugInInfo
@@ -217,36 +217,36 @@ void G_GNUC_NORETURN gimp_quit         (void);
 
 /* Install a procedure in the procedure database.
  */
-void          gimp_install_procedure   (const gchar     *name,
-                                        const gchar     *blurb,
-                                        const gchar     *help,
-                                        const gchar     *author,
-                                        const gchar     *copyright,
-                                        const gchar     *date,
-                                        const gchar     *menu_path,
-                                        const gchar     *image_types,
-                                        GimpPDBProcType  type,
-                                        gint             n_params,
-                                        gint             n_return_vals,
-                                        GimpParamDef    *params,
-                                        GimpParamDef    *return_vals);
+void          gimp_install_procedure   (const gchar        *name,
+                                        const gchar        *blurb,
+                                        const gchar        *help,
+                                        const gchar        *author,
+                                        const gchar        *copyright,
+                                        const gchar        *date,
+                                        const gchar        *menu_path,
+                                        const gchar        *image_types,
+                                        GimpPDBProcType     type,
+                                        gint                n_params,
+                                        gint                n_return_vals,
+                                        const GimpParamDef *params,
+                                        const GimpParamDef *return_vals);
 
 /* Install a temporary procedure in the procedure database.
  */
-void          gimp_install_temp_proc   (const gchar     *name,
-                                        const gchar     *blurb,
-                                        const gchar     *help,
-                                        const gchar     *author,
-                                        const gchar     *copyright,
-                                        const gchar     *date,
-                                        const gchar     *menu_path,
-                                        const gchar     *image_types,
-                                        GimpPDBProcType  type,
-                                        gint             n_params,
-                                        gint             n_return_vals,
-                                        GimpParamDef    *params,
-                                        GimpParamDef    *return_vals,
-                                        GimpRunProc      run_proc);
+void          gimp_install_temp_proc   (const gchar        *name,
+                                        const gchar        *blurb,
+                                        const gchar        *help,
+                                        const gchar        *author,
+                                        const gchar        *copyright,
+                                        const gchar        *date,
+                                        const gchar        *menu_path,
+                                        const gchar        *image_types,
+                                        GimpPDBProcType     type,
+                                        gint                n_params,
+                                        gint                n_return_vals,
+                                        const GimpParamDef *params,
+                                        const GimpParamDef *return_vals,
+                                        GimpRunProc         run_proc);
 
 /* Uninstall a temporary procedure
  */
@@ -279,7 +279,7 @@ GimpParam   * gimp_run_procedure       (const gchar     *name,
 GimpParam   * gimp_run_procedure2      (const gchar     *name,
                                         gint            *n_return_vals,
                                         gint             n_params,
-                                        GimpParam       *params);
+                                        const GimpParam *params);
 
 /* Destroy the an array of parameters. This is useful for
  *  destroying the return values returned by a call to
@@ -314,7 +314,7 @@ const gchar * gimp_get_progname        (void) G_GNUC_CONST;
 void          gimp_attach_new_parasite (const gchar    *name,
                                         gint            flags,
                                         gint            size,
-                                        const gpointer  data);
+                                        gconstpointer   data);
 
 
 G_END_DECLS
diff --git a/libgimp/gimpchannel.c b/libgimp/gimpchannel.c
index 80e0f8f3f3..18bb914e8c 100644
--- a/libgimp/gimpchannel.c
+++ b/libgimp/gimpchannel.c
@@ -46,12 +46,12 @@
  * Returns: The newly created channel.
  */
 gint32
-gimp_channel_new (gint32   image_ID,
-		  gchar   *name,
-		  guint    width,
-		  guint    height,
-		  gdouble  opacity,
-		  GimpRGB *color)
+gimp_channel_new (gint32         image_ID,
+		  const gchar   *name,
+		  guint          width,
+		  guint          height,
+		  gdouble        opacity,
+		  const GimpRGB *color)
 {
   return _gimp_channel_new (image_ID,
 			    width,
diff --git a/libgimp/gimpchannel.h b/libgimp/gimpchannel.h
index 48c81d8443..e8db8215fe 100644
--- a/libgimp/gimpchannel.h
+++ b/libgimp/gimpchannel.h
@@ -30,12 +30,12 @@ G_BEGIN_DECLS
 #define gimp_channel_get_image_id  gimp_drawable_image
 
 
-gint32  gimp_channel_new (gint32    image_ID,
-			  gchar    *name,
-			  guint     width,
-			  guint     height,
-			  gdouble   opacity,
-			  GimpRGB  *color);
+gint32  gimp_channel_new (gint32         image_ID,
+			  const gchar   *name,
+			  guint          width,
+			  guint          height,
+			  gdouble        opacity,
+			  const GimpRGB *color);
 
 
 G_END_DECLS
diff --git a/libgimp/gimpdrawable.c b/libgimp/gimpdrawable.c
index 326093a91c..7eb45a1065 100644
--- a/libgimp/gimpdrawable.c
+++ b/libgimp/gimpdrawable.c
@@ -103,7 +103,6 @@ gimp_drawable_delete (GimpDrawable *drawable)
     }
 }
 
-
 gchar *
 gimp_drawable_name (gint32 drawable_ID)
 {
@@ -113,7 +112,6 @@ gimp_drawable_name (gint32 drawable_ID)
   return gimp_channel_get_name (drawable_ID);
 }
 
-
 gboolean
 gimp_drawable_visible (gint32 drawable_ID)
 {
@@ -123,10 +121,9 @@ gimp_drawable_visible (gint32 drawable_ID)
   return gimp_channel_get_visible (drawable_ID);
 }
 
-
 void
-gimp_drawable_set_name (gint32  drawable_ID,
-			gchar  *name)
+gimp_drawable_set_name (gint32       drawable_ID,
+			const gchar *name)
 {
   if (gimp_drawable_is_layer (drawable_ID))
     gimp_layer_set_name (drawable_ID, name);
@@ -268,7 +265,7 @@ gimp_drawable_attach_new_parasite (gint32          drawable_ID,
 				   const gchar    *name, 
 				   gint            flags,
 				   gint            size, 
-				   const gpointer  data)
+				   gconstpointer   data)
 {
   GimpParasite *parasite = gimp_parasite_new (name, flags, size, data);
 
diff --git a/libgimp/gimpdrawable.h b/libgimp/gimpdrawable.h
index b5031aae30..1e5524d5dd 100644
--- a/libgimp/gimpdrawable.h
+++ b/libgimp/gimpdrawable.h
@@ -50,7 +50,7 @@ void           gimp_drawable_delete              (GimpDrawable   *drawable);
 gchar        * gimp_drawable_name                (gint32          drawable_ID);
 gboolean       gimp_drawable_visible             (gint32          drawable_ID);
 void           gimp_drawable_set_name            (gint32          drawable_ID,
-						  gchar          *name);
+						  const gchar    *name);
 void           gimp_drawable_set_visible         (gint32          drawable_ID,
 						  gboolean        visible);
 GimpTile     * gimp_drawable_get_tile            (GimpDrawable   *drawable,
@@ -71,7 +71,7 @@ void           gimp_drawable_attach_new_parasite (gint32          drawable_ID,
 						  const gchar    *name, 
 						  gint            flags,
 						  gint            size, 
-						  const gpointer  data);
+						  gconstpointer   data);
 
 G_END_DECLS
 
diff --git a/libgimp/gimpimage.c b/libgimp/gimpimage.c
index 915b9baa57..65869d6e65 100644
--- a/libgimp/gimpimage.c
+++ b/libgimp/gimpimage.c
@@ -68,9 +68,9 @@ gimp_image_get_cmap (gint32  image_ID,
  * Returns: TRUE on success.
  */
 gboolean
-gimp_image_set_cmap (gint32  image_ID,
-		     guchar *cmap,
-		     gint    num_colors)
+gimp_image_set_cmap (gint32        image_ID,
+		     const guchar *cmap,
+		     gint          num_colors)
 {
   return _gimp_image_set_cmap (image_ID,
 			       num_colors * 3,
@@ -117,11 +117,11 @@ gimp_image_get_thumbnail_data (gint32  image_ID,
  * See Also: gimp_image_parasite_attach()
  */
 void
-gimp_image_attach_new_parasite (gint32          image_ID, 
-				const gchar    *name, 
-				gint            flags,
-				gint            size, 
-				const gpointer  data)
+gimp_image_attach_new_parasite (gint32         image_ID, 
+				const gchar   *name, 
+				gint           flags,
+				gint           size, 
+				gconstpointer  data)
 {
   GimpParasite *parasite = gimp_parasite_new (name, flags, size, data);
 
diff --git a/libgimp/gimpimage.h b/libgimp/gimpimage.h
index e3e3816145..5e1417618a 100644
--- a/libgimp/gimpimage.h
+++ b/libgimp/gimpimage.h
@@ -34,7 +34,7 @@ G_BEGIN_DECLS
 guchar   * gimp_image_get_cmap            (gint32          image_ID,
 					   gint           *num_colors);
 gboolean   gimp_image_set_cmap            (gint32          image_ID,
-					   guchar         *cmap,
+					   const guchar   *cmap,
 					   gint            num_colors);
   
 guchar   * gimp_image_get_thumbnail_data  (gint32          image_ID,
@@ -46,7 +46,7 @@ void       gimp_image_attach_new_parasite (gint32          image_ID,
 					   const gchar    *name, 
 					   gint            flags,
 					   gint            size, 
-					   const gpointer  data);
+					   gconstpointer   data);
 
 
 G_END_DECLS
diff --git a/libgimp/gimplayer.c b/libgimp/gimplayer.c
index 7723880006..0cbad892e6 100644
--- a/libgimp/gimplayer.c
+++ b/libgimp/gimplayer.c
@@ -47,7 +47,7 @@
  */
 gint32
 gimp_layer_new (gint32                image_ID,
-		gchar                *name,
+		const gchar          *name,
 		gint                  width,
 		gint                  height,
 		GimpImageType         type,
diff --git a/libgimp/gimplayer.h b/libgimp/gimplayer.h
index fcdf4d7c36..5bd444147c 100644
--- a/libgimp/gimplayer.h
+++ b/libgimp/gimplayer.h
@@ -34,7 +34,7 @@ G_BEGIN_DECLS
 
 
 gint32   gimp_layer_new  (gint32                image_ID,
-			  gchar                *name,
+			  const gchar          *name,
 			  gint                  width,
 			  gint                  height,
 			  GimpImageType         type,
diff --git a/libgimp/gimpmisc.c b/libgimp/gimpmisc.c
index d1d2b913b6..58ed34e9f6 100644
--- a/libgimp/gimpmisc.c
+++ b/libgimp/gimpmisc.c
@@ -169,7 +169,7 @@ void
 gimp_pixel_fetcher_put_pixel (GimpPixelFetcher *pf,
 			      gint              x,
 			      gint              y,
-			      guchar           *pixel)
+			      const guchar     *pixel)
 {
   guchar *p;
   gint    i;
diff --git a/libgimp/gimpmisc.h b/libgimp/gimpmisc.h
index 6b9a19bcdc..e9a7347511 100644
--- a/libgimp/gimpmisc.h
+++ b/libgimp/gimpmisc.h
@@ -57,7 +57,7 @@ void               gimp_pixel_fetcher_get_pixel2   (GimpPixelFetcher *pf,
 void               gimp_pixel_fetcher_put_pixel    (GimpPixelFetcher *pf, 
 						    gint              x,
 						    gint              y,
-						    guchar           *pixel);
+						    const guchar     *pixel);
 void               gimp_pixel_fetcher_destroy      (GimpPixelFetcher *pf);
 
 
diff --git a/libgimp/gimpmiscui.c b/libgimp/gimpmiscui.c
index 44af2ea95b..8db9a42d06 100644
--- a/libgimp/gimpmiscui.c
+++ b/libgimp/gimpmiscui.c
@@ -92,11 +92,14 @@ gimp_fixme_preview_free (GimpFixMePreview *preview)
 }
 
 GimpFixMePreview*
-gimp_fixme_preview_new2 (GimpImageType drawable_type, gboolean has_frame)
+gimp_fixme_preview_new2 (GimpImageType drawable_type,
+                         gboolean      has_frame)
 {
-  GimpFixMePreview *preview = g_new0 (GimpFixMePreview, 1);
-  guchar    *buf     = NULL;
-  gint       y;
+  GimpFixMePreview *preview;
+  guchar           *buf = NULL;
+  gint              y;
+
+  preview = g_new0 (GimpFixMePreview, 1);
 
   switch (drawable_type)
     {
@@ -140,14 +143,14 @@ gimp_fixme_preview_new2 (GimpImageType drawable_type, gboolean has_frame)
 
 void
 gimp_fixme_preview_put_pixel (GimpFixMePreview *preview,
-			      gint x,
-			      gint y,
-			      const guchar *pixel)
+			      gint              x,
+			      gint              y,
+			      const guchar     *pixel)
 {
   guchar *dest;
 
-  g_assert (x >= 0 && x < PREVIEW_SIZE);
-  g_assert (y >= 0 && y < PREVIEW_SIZE);
+  g_return_if_fail (x >= 0 && x < PREVIEW_SIZE);
+  g_return_if_fail (y >= 0 && y < PREVIEW_SIZE);
 
   dest = preview->buffer + y * preview->rowstride;
 
@@ -167,14 +170,14 @@ gimp_fixme_preview_put_pixel (GimpFixMePreview *preview,
 
 void
 gimp_fixme_preview_get_pixel (GimpFixMePreview *preview,
-			      gint x,
-			      gint y,
-			      guchar *pixel)
+			      gint              x,
+			      gint              y,
+			      guchar           *pixel)
 {
-  guchar *src;
+  const guchar *src;
 
-  g_assert (x >= 0 && x < PREVIEW_SIZE);
-  g_assert (y >= 0 && y < PREVIEW_SIZE);
+  g_return_if_fail (x >= 0 && x < PREVIEW_SIZE);
+  g_return_if_fail (y >= 0 && y < PREVIEW_SIZE);
 
   src = preview->buffer + y * preview->rowstride;
 
@@ -196,52 +199,54 @@ void
 gimp_fixme_preview_do_row (GimpFixMePreview *preview,
 			   gint              row,
 			   gint              width,
-			   guchar           *src)
+			   const guchar     *src)
 {
   gint    x;
   guchar *p0 = preview->even;
   guchar *p1 = preview->odd;
-  gint bpp = preview->bpp;
+  gint    bpp = preview->bpp;
   gdouble r, g, b, a;
   gdouble c0, c1;
 
   for (x = 0; x < width; x++) 
     {
-      if (bpp == 4)
-	{
+      switch (bpp)
+        {
+        case 4:
 	  r = ((gdouble) src[x*4 + 0]) / 255.0;
 	  g = ((gdouble) src[x*4 + 1]) / 255.0;
 	  b = ((gdouble) src[x*4 + 2]) / 255.0;
 	  a = ((gdouble) src[x*4 + 3]) / 255.0;
-	}
-      else if (bpp == 3)
-	{
+          break;
+
+        case 3:
 	  r = ((gdouble) src[x*3 + 0]) / 255.0;
 	  g = ((gdouble) src[x*3 + 1]) / 255.0;
 	  b = ((gdouble) src[x*3 + 2]) / 255.0;
 	  a = 1.0;
-	}
-      else
-	{
+          break;
+
+        default:
 	  if (preview->cmap)
 	    {
 	      gint index = MIN (src[x*bpp], preview->ncolors - 1);
 	      
-	      r = ((gdouble)preview->cmap[index * 3 + 0]) / 255.0;
-	      g = ((gdouble)preview->cmap[index * 3 + 1]) / 255.0;
-	      b = ((gdouble)preview->cmap[index * 3 + 2]) / 255.0;
+	      r = ((gdouble) preview->cmap[index * 3 + 0]) / 255.0;
+	      g = ((gdouble) preview->cmap[index * 3 + 1]) / 255.0;
+	      b = ((gdouble) preview->cmap[index * 3 + 2]) / 255.0;
 	    }
 	  else
 	    {
-	      r = ((gdouble)src[x*bpp + 0]) / 255.0;
+	      r = ((gdouble) src[x*bpp + 0]) / 255.0;
 	      g = b = r;
 	    }
 	  
 	  if (bpp == 2)
-	    a = ((gdouble)src[x*2 + 1]) / 255.0;
+	    a = ((gdouble) src[x*2 + 1]) / 255.0;
 	  else
 	    a = 1.0;
-	}
+          break;
+        }
       
       if ((x / GIMP_CHECK_SIZE_SM) & 1) 
 	{
@@ -266,12 +271,12 @@ gimp_fixme_preview_do_row (GimpFixMePreview *preview,
   if ((row / GIMP_CHECK_SIZE_SM) & 1)
     {
       gtk_preview_draw_row (GTK_PREVIEW (preview->widget), 
-                            (guchar *) preview->odd,  0, row, width); 
+                            preview->odd,  0, row, width); 
     }
   else
     {
       gtk_preview_draw_row (GTK_PREVIEW (preview->widget),
-                            (guchar *) preview->even, 0, row, width); 
+                            preview->even, 0, row, width); 
     }
 }
 
@@ -280,8 +285,8 @@ gimp_fixme_preview_update (GimpFixMePreview      *preview,
 			   GimpFixeMePreviewFunc  func,
 			   gpointer               data)
 {
-  gint    x, y;
   guchar *buffer;
+  gint    x, y;
   gint    bpp;
 
   bpp    = preview->bpp;
@@ -289,8 +294,8 @@ gimp_fixme_preview_update (GimpFixMePreview      *preview,
 
   for (y = 0; y < preview->height; y++)
     {
-      guchar *src  = preview->cache + y * preview->rowstride;
-      guchar *dest = buffer;
+      const guchar *src  = preview->cache + y * preview->rowstride;
+      guchar       *dest = buffer;
 
       for (x = 0; x < preview->width; x++)
 	{
@@ -312,11 +317,11 @@ void
 gimp_fixme_preview_fill_with_thumb (GimpFixMePreview *preview,
 				    gint32            drawable_ID)
 {
-  gint    bpp;
-  gint    y;
-  gint    width  = PREVIEW_SIZE;
-  gint    height = PREVIEW_SIZE;
-  guchar *src;
+  const guchar *src;
+  gint          bpp;
+  gint          y;
+  gint          width  = PREVIEW_SIZE;
+  gint          height = PREVIEW_SIZE;
 
   preview->cache = 
     gimp_drawable_get_thumbnail_data (drawable_ID, &width, &height, &bpp);
@@ -369,7 +374,7 @@ gimp_fixme_preview_fill (GimpFixMePreview *preview,
   gint          x1, x2, y1, y2;
   gint          bpp;
   gint          y;
-  guchar       *src;
+  const guchar *src;
   
   gimp_drawable_mask_bounds (drawable->drawable_id, &x1, &y1, &x2, &y2);
 
@@ -504,8 +509,8 @@ gimp_fixme_preview_fill_scaled (GimpFixMePreview *preview,
   preview->height = GTK_PREVIEW (preview->widget)->buffer_height;
 }
 
-GList*
-gimp_plug_in_parse_path (gchar       *path_name,
+GList *
+gimp_plug_in_parse_path (const gchar *path_name,
 			 const gchar *dir_name)
 {
   GList *path_list = NULL;
diff --git a/libgimp/gimpmiscui.h b/libgimp/gimpmiscui.h
index c13760f849..ead317d3ab 100644
--- a/libgimp/gimpmiscui.h
+++ b/libgimp/gimpmiscui.h
@@ -39,7 +39,8 @@ G_BEGIN_DECLS
  * Don't say I didn't warn you (Maurits).
  */
 
-typedef struct {
+typedef struct
+{
   GtkWidget *widget;
   GtkWidget *frame;
   guchar    *cache;
@@ -57,40 +58,45 @@ typedef struct {
   gboolean   is_gray;
 } GimpFixMePreview;
 
-typedef void (*GimpFixeMePreviewFunc)(guchar *src, guchar *dest, 
-				      gint bpp, gpointer data);
+typedef void (*GimpFixeMePreviewFunc)  (const guchar *src,
+                                        guchar       *dest, 
+                                        gint          bpp,
+                                        gpointer      data);
 
-GimpFixMePreview *gimp_fixme_preview_new (GimpDrawable *drawable,
-					  gboolean has_frame);
-GimpFixMePreview *gimp_fixme_preview_new2 (GimpImageType drawable_type, 
-					   gboolean has_frame);
-void gimp_fixme_preview_free (GimpFixMePreview *preview);
+GimpFixMePreview * gimp_fixme_preview_new    (GimpDrawable     *drawable,
+                                              gboolean          has_frame);
+GimpFixMePreview * gimp_fixme_preview_new2   (GimpImageType     drawable_type, 
+                                              gboolean          has_frame);
+void               gimp_fixme_preview_free   (GimpFixMePreview *preview);
 
-void gimp_fixme_preview_update (GimpFixMePreview *preview,
-				GimpFixeMePreviewFunc func,
-				gpointer data);
+void               gimp_fixme_preview_update (GimpFixMePreview *preview,
+                                              GimpFixeMePreviewFunc func,
+                                              gpointer          data);
 
-void gimp_fixme_preview_fill_with_thumb (GimpFixMePreview *preview,
-					 gint32     drawable_ID);
-void gimp_fixme_preview_fill (GimpFixMePreview *preview, 
-			      GimpDrawable *drawable);
-void gimp_fixme_preview_fill_scaled (GimpFixMePreview *preview, 
-				     GimpDrawable *drawable);
-void gimp_fixme_preview_do_row (GimpFixMePreview *preview,
-				gint    row,
-				gint    width,
-				guchar *src);
+void      gimp_fixme_preview_fill_with_thumb (GimpFixMePreview *preview,
+                                              gint32            drawable_ID);
+void      gimp_fixme_preview_fill            (GimpFixMePreview *preview, 
+                                              GimpDrawable     *drawable);
+void      gimp_fixme_preview_fill_scaled     (GimpFixMePreview *preview, 
+                                              GimpDrawable     *drawable);
 
-void gimp_fixme_preview_put_pixel (GimpFixMePreview *preview,
-				   gint x,
-				   gint y,
-				   const guchar *pixel);
-void gimp_fixme_preview_get_pixel (GimpFixMePreview *preview,
-				   gint x,
-				   gint y,
-				   guchar *pixel);
+void      gimp_fixme_preview_do_row          (GimpFixMePreview *preview,
+                                              gint              row,
+                                              gint              width,
+                                              const guchar     *src);
+
+void      gimp_fixme_preview_put_pixel       (GimpFixMePreview *preview,
+                                              gint              x,
+                                              gint              y,
+                                              const guchar     *pixel);
+void      gimp_fixme_preview_get_pixel       (GimpFixMePreview *preview,
+                                              gint              x,
+                                              gint              y,
+                                              guchar           *pixel);
+
+GList   * gimp_plug_in_parse_path            (const gchar *path_name,
+                                              const gchar *dir_name);
 
-GList *gimp_plug_in_parse_path (gchar *path_name, const gchar *dir_name);
 
 G_END_DECLS
 
diff --git a/libgimp/gimppixelfetcher.c b/libgimp/gimppixelfetcher.c
index d1d2b913b6..58ed34e9f6 100644
--- a/libgimp/gimppixelfetcher.c
+++ b/libgimp/gimppixelfetcher.c
@@ -169,7 +169,7 @@ void
 gimp_pixel_fetcher_put_pixel (GimpPixelFetcher *pf,
 			      gint              x,
 			      gint              y,
-			      guchar           *pixel)
+			      const guchar     *pixel)
 {
   guchar *p;
   gint    i;
diff --git a/libgimp/gimppixelfetcher.h b/libgimp/gimppixelfetcher.h
index 6b9a19bcdc..e9a7347511 100644
--- a/libgimp/gimppixelfetcher.h
+++ b/libgimp/gimppixelfetcher.h
@@ -57,7 +57,7 @@ void               gimp_pixel_fetcher_get_pixel2   (GimpPixelFetcher *pf,
 void               gimp_pixel_fetcher_put_pixel    (GimpPixelFetcher *pf, 
 						    gint              x,
 						    gint              y,
-						    guchar           *pixel);
+						    const guchar     *pixel);
 void               gimp_pixel_fetcher_destroy      (GimpPixelFetcher *pf);
 
 
diff --git a/libgimp/gimppixelrgn.c b/libgimp/gimppixelrgn.c
index 7907a92d50..618136eac4 100644
--- a/libgimp/gimppixelrgn.c
+++ b/libgimp/gimppixelrgn.c
@@ -322,13 +322,13 @@ gimp_pixel_rgn_get_rect (GimpPixelRgn *pr,
 
 void
 gimp_pixel_rgn_set_pixel (GimpPixelRgn *pr,
-			  guchar       *buf,
+			  const guchar *buf,
 			  gint          x,
 			  gint          y)
 {
   GimpTile *tile;
   guchar   *tile_data;
-  gint b;
+  gint      b;
 
   g_return_if_fail (pr != NULL && pr->drawable != NULL);
   g_return_if_fail (buf != NULL);
@@ -338,7 +338,8 @@ gimp_pixel_rgn_set_pixel (GimpPixelRgn *pr,
   tile = gimp_drawable_get_tile2 (pr->drawable, pr->shadow, x, y);
   gimp_tile_ref (tile);
 
-  tile_data = tile->data + tile->bpp * (tile->ewidth * (y % TILE_HEIGHT) + (x % TILE_WIDTH));
+  tile_data = tile->data + tile->bpp * (tile->ewidth *
+                                        (y % TILE_HEIGHT) + (x % TILE_WIDTH));
 
   for (b = 0; b < tile->bpp; b++)
     *tile_data++ = *buf++;
@@ -348,18 +349,18 @@ gimp_pixel_rgn_set_pixel (GimpPixelRgn *pr,
 
 void
 gimp_pixel_rgn_set_row (GimpPixelRgn *pr,
-			guchar       *buf,
+			const guchar *buf,
 			gint          x,
 			gint          y,
 			gint          width)
 {
   GimpTile *tile;
   guchar   *tile_data;
-  gint inc, min;
-  gint end;
-  gint boundary;
+  gint      inc, min;
+  gint      end;
+  gint      boundary;
 #ifndef MEMCPY_IS_NICE
-  gint b;
+  gint      b;
 #endif
 
   g_return_if_fail (pr != NULL && pr->drawable != NULL);
@@ -399,17 +400,17 @@ gimp_pixel_rgn_set_row (GimpPixelRgn *pr,
 
 void
 gimp_pixel_rgn_set_col (GimpPixelRgn *pr,
-			guchar       *buf,
+			const guchar *buf,
 			gint          x,
 			gint          y,
 			gint          height)
 {
   GimpTile *tile;
   guchar   *tile_data;
-  gint inc;
-  gint end;
-  gint boundary;
-  gint b;
+  gint      inc;
+  gint      end;
+  gint      boundary;
+  gint      b;
 
   g_return_if_fail (pr != NULL && pr->drawable != NULL);
   g_return_if_fail (buf != NULL);
@@ -441,7 +442,7 @@ gimp_pixel_rgn_set_col (GimpPixelRgn *pr,
 
 void
 gimp_pixel_rgn_set_rect (GimpPixelRgn *pr,
-			 guchar       *buf,
+			 const guchar *buf,
 			 gint          x,
 			 gint          y,
 			 gint          width,
@@ -451,14 +452,14 @@ gimp_pixel_rgn_set_rect (GimpPixelRgn *pr,
   guchar   *src;
   guchar   *dest;
   gulong    bufstride;
-  gint xstart, ystart;
-  gint xend, yend;
-  gint xboundary;
-  gint yboundary;
-  gint xstep, ystep;
-  gint ty, bpp;
+  gint      xstart, ystart;
+  gint      xend, yend;
+  gint      xboundary;
+  gint      yboundary;
+  gint      xstep, ystep;
+  gint      ty, bpp;
 #ifndef MEMCPY_IS_NICE
-  gint b, tx;
+  gint      b, tx;
 #endif
 
   g_return_if_fail (pr != NULL && pr->drawable != NULL);
@@ -495,7 +496,8 @@ gimp_pixel_rgn_set_rect (GimpPixelRgn *pr,
 	  for (ty = y; ty < yboundary; ty++)
 	    {
 	      src = buf + bufstride * (ty - ystart) + bpp * (x - xstart);
-	      dest = tile->data + tile->bpp * (tile->ewidth * (ty % TILE_HEIGHT) + (x % TILE_WIDTH));
+	      dest = tile->data + tile->bpp * (tile->ewidth *
+                                               (ty % TILE_HEIGHT) + (x % TILE_WIDTH));
 
 #ifdef MEMCPY_IS_NICE
 	      memcpy ((void *)dest, (const void *)src, (xboundary-x)*bpp); 
@@ -523,7 +525,7 @@ gimp_pixel_rgns_register2 (gint           nrgns,
   GimpPixelRgn         *pr;
   GimpPixelRgnHolder   *prh;
   GimpPixelRgnIterator *pri;
-  gboolean found;
+  gboolean              found;
 
   pri = g_new (GimpPixelRgnIterator, 1);
   pri->pixel_regions = NULL;
@@ -569,9 +571,9 @@ gimp_pixel_rgns_register (gint nrgns,
 			  ...)
 {
   GimpPixelRgn **prs;
-  gpointer pri;
-  gint n;
-  va_list ap;
+  gpointer       pri;
+  gint           n;
+  va_list        ap;
 
   prs = g_new (GimpPixelRgn *, nrgns);
 
@@ -592,9 +594,9 @@ gimp_pixel_rgns_register (gint nrgns,
 gpointer
 gimp_pixel_rgns_process (gpointer pri_ptr)
 {
-  GSList *list;
   GimpPixelRgnHolder   *prh;
   GimpPixelRgnIterator *pri;
+  GSList               *list;
 
   pri = (GimpPixelRgnIterator*) pri_ptr;
   pri->process_count++;
@@ -614,11 +616,15 @@ gimp_pixel_rgns_process (gpointer pri_ptr)
 	   */
 	  prh->pr->process_count++;
 
-	  /*  Unref the last referenced tile if the underlying region is a tile manager  */
+	  /*  Unref the last referenced tile if the underlying region
+           *  is a tile manager
+           */
 	  if (prh->pr->drawable)
 	    {
-	      GimpTile *tile = gimp_drawable_get_tile2 (prh->pr->drawable, prh->pr->shadow,
-						    prh->pr->x, prh->pr->y);
+	      GimpTile *tile = gimp_drawable_get_tile2 (prh->pr->drawable,
+                                                        prh->pr->shadow,
+                                                        prh->pr->x,
+                                                        prh->pr->y);
 	      gimp_tile_unref (tile, prh->pr->dirty);
 	    }
 
@@ -640,12 +646,13 @@ static gint
 gimp_get_portion_width (GimpPixelRgnIterator *pri)
 {
   GimpPixelRgnHolder *prh;
-  GSList *list;
-  gint    min_width = G_MAXINT;
-  gint    width;
+  GSList             *list;
+  gint                min_width = G_MAXINT;
+  gint                width;
 
-  /* Find the minimum width to the next vertical tile (in the case of a tile manager)
-   * or to the end of the pixel region (in the case of no tile manager)
+  /* Find the minimum width to the next vertical tile (in the case of
+   * a tile manager) or to the end of the pixel region (in the case of
+   * no tile manager)
    */
 
   list = pri->pixel_regions;
@@ -683,12 +690,13 @@ static int
 gimp_get_portion_height (GimpPixelRgnIterator *pri)
 {
   GimpPixelRgnHolder *prh;
-  GSList *list;
-  gint    min_height = G_MAXINT;
-  gint    height;
+  GSList             *list;
+  gint                min_height = G_MAXINT;
+  gint                height;
 
-  /* Find the minimum height to the next vertical tile (in the case of a tile manager)
-   * or to the end of the pixel region (in the case of no tile manager)
+  /* Find the minimum height to the next vertical tile (in the case of
+   * a tile manager) or to the end of the pixel region (in the case of
+   * no tile manager)
    */
 
   list = pri->pixel_regions;
@@ -781,14 +789,18 @@ gimp_pixel_rgn_configure (GimpPixelRgnHolder   *prh,
       gint      offx;
       gint      offy;
 
-      tile = gimp_drawable_get_tile2 (prh->pr->drawable, prh->pr->shadow, prh->pr->x, prh->pr->y);
+      tile = gimp_drawable_get_tile2 (prh->pr->drawable,
+                                      prh->pr->shadow,
+                                      prh->pr->x,
+                                      prh->pr->y);
       gimp_tile_ref (tile);
 
       offx = prh->pr->x % TILE_WIDTH;
       offy = prh->pr->y % TILE_HEIGHT;
 
       prh->pr->rowstride = tile->ewidth * prh->pr->bpp;
-      prh->pr->data = tile->data + offy * prh->pr->rowstride + offx * prh->pr->bpp;
+      prh->pr->data = (tile->data +
+                       offy * prh->pr->rowstride + offx * prh->pr->bpp);
     }
   else
     {
diff --git a/libgimp/gimppixelrgn.h b/libgimp/gimppixelrgn.h
index 029ba4e9da..96c3e7d865 100644
--- a/libgimp/gimppixelrgn.h
+++ b/libgimp/gimppixelrgn.h
@@ -75,21 +75,21 @@ void      gimp_pixel_rgn_get_rect   (GimpPixelRgn  *pr,
 				     gint           width,
 				     gint           height);
 void      gimp_pixel_rgn_set_pixel  (GimpPixelRgn  *pr,
-				     guchar        *buf,
+				     const guchar  *buf,
 				     gint           x,
 				     gint           y);
 void      gimp_pixel_rgn_set_row    (GimpPixelRgn  *pr,
-				     guchar        *buf,
+				     const guchar  *buf,
 				     gint           x,
 				     gint           y,
 				     gint           width);
 void      gimp_pixel_rgn_set_col    (GimpPixelRgn  *pr,
-				     guchar        *buf,
+				     const guchar  *buf,
 				     gint           x,
 				     gint           y,
 				     gint           height);
 void      gimp_pixel_rgn_set_rect   (GimpPixelRgn  *pr,
-				     guchar        *buf,
+				     const guchar  *buf,
 				     gint           x,
 				     gint           y,
 				     gint           width,
diff --git a/libgimp/gimpproceduraldb.c b/libgimp/gimpproceduraldb.c
index 779f9aa020..6608614140 100644
--- a/libgimp/gimpproceduraldb.c
+++ b/libgimp/gimpproceduraldb.c
@@ -51,7 +51,7 @@
  * Returns: TRUE on success.
  */
 gboolean
-gimp_procedural_db_proc_info (gchar            *procedure,
+gimp_procedural_db_proc_info (const gchar      *procedure,
 			      gchar           **blurb,
 			      gchar           **help,
 			      gchar           **author,
@@ -130,8 +130,8 @@ gimp_procedural_db_proc_info (gchar            *procedure,
  * the identifier
  */
 gboolean
-gimp_procedural_db_get_data (gchar    *identifier,
-			     gpointer  data)
+gimp_procedural_db_get_data (const gchar *identifier,
+			     gpointer     data)
 {
   gint      size;
   guint8   *hack;
@@ -164,9 +164,9 @@ gimp_procedural_db_get_data (gchar    *identifier,
  * Returns: TRUE on success.
  */
 gboolean
-gimp_procedural_db_set_data (gchar    *identifier,
-			     gpointer  data,
-			     guint32   bytes)
+gimp_procedural_db_set_data (const gchar *identifier,
+			     gpointer     data,
+			     guint32      bytes)
 {
   return _gimp_procedural_db_set_data (identifier,
 				       bytes,
diff --git a/libgimp/gimpproceduraldb.h b/libgimp/gimpproceduraldb.h
index cafc925135..9ad4c8746e 100644
--- a/libgimp/gimpproceduraldb.h
+++ b/libgimp/gimpproceduraldb.h
@@ -27,7 +27,7 @@ G_BEGIN_DECLS
 /* For information look into the C source or the html documentation */
 
 
-gboolean gimp_procedural_db_proc_info    (gchar            *procedure,
+gboolean gimp_procedural_db_proc_info    (const gchar      *procedure,
 					  gchar           **blurb,
 					  gchar           **help,
 					  gchar           **author,
@@ -38,9 +38,9 @@ gboolean gimp_procedural_db_proc_info    (gchar            *procedure,
 					  gint             *num_values,
 					  GimpParamDef    **args,
 					  GimpParamDef    **return_vals);
-gboolean gimp_procedural_db_get_data     (gchar            *identifier,
+gboolean gimp_procedural_db_get_data     (const gchar      *identifier,
 					  gpointer          data);
-gboolean gimp_procedural_db_set_data     (gchar            *identifier,
+gboolean gimp_procedural_db_set_data     (const gchar      *identifier,
 					  gpointer          data,
 					  guint32           bytes);
 
diff --git a/libgimp/gimpregioniterator.c b/libgimp/gimpregioniterator.c
index d1d2b913b6..58ed34e9f6 100644
--- a/libgimp/gimpregioniterator.c
+++ b/libgimp/gimpregioniterator.c
@@ -169,7 +169,7 @@ void
 gimp_pixel_fetcher_put_pixel (GimpPixelFetcher *pf,
 			      gint              x,
 			      gint              y,
-			      guchar           *pixel)
+			      const guchar     *pixel)
 {
   guchar *p;
   gint    i;
diff --git a/libgimp/gimpregioniterator.h b/libgimp/gimpregioniterator.h
index 6b9a19bcdc..e9a7347511 100644
--- a/libgimp/gimpregioniterator.h
+++ b/libgimp/gimpregioniterator.h
@@ -57,7 +57,7 @@ void               gimp_pixel_fetcher_get_pixel2   (GimpPixelFetcher *pf,
 void               gimp_pixel_fetcher_put_pixel    (GimpPixelFetcher *pf, 
 						    gint              x,
 						    gint              y,
-						    guchar           *pixel);
+						    const guchar     *pixel);
 void               gimp_pixel_fetcher_destroy      (GimpPixelFetcher *pf);
 
 
diff --git a/libgimpbase/gimpparasite.c b/libgimpbase/gimpparasite.c
index e30d67b2ba..3d04002171 100644
--- a/libgimpbase/gimpparasite.c
+++ b/libgimpbase/gimpparasite.c
@@ -66,7 +66,7 @@ GimpParasite *
 gimp_parasite_new (const gchar    *name, 
 		   guint32         flags,
 		   guint32         size, 
-		   const gpointer  data)
+		   gconstpointer   data)
 {
   GimpParasite *parasite;
 
diff --git a/libgimpbase/gimpparasite.h b/libgimpbase/gimpparasite.h
index c16e3de023..62472a3173 100644
--- a/libgimpbase/gimpparasite.h
+++ b/libgimpbase/gimpparasite.h
@@ -53,7 +53,7 @@ struct _GimpParasite
 GimpParasite * gimp_parasite_new           (const gchar        *name, 
                                             guint32             flags,
                                             guint32             size, 
-                                            const gpointer      data);
+                                            gconstpointer       data);
 void           gimp_parasite_free          (GimpParasite       *parasite);
 
 GimpParasite * gimp_parasite_copy          (const GimpParasite *parasite);