Bug 792141 - Replace jasper with openjpeg.

Made plug-in support the RGB and grayscale with alpha.

Comment by Jehan: this makes the original branch work finally usable on
some JPEG 2000 images. Support of the format is not complete yet though
but at least the port to OpenJPEG is now in usable test.

plug-ins/common/file-jp2-load.c

@@ -141,7 +141,7 @@ query (void)
                           load_args, load_return_vals);
 
   gimp_register_magic_load_handler (LOAD_PROC,
-                                    "jp2",
+                                    "jp2,jpc,jpx,j2k,jpf",
                                     "",
                                     "4,string,jP,0,string,\xff\x4f\xff\x51\x00");
 
@@ -913,16 +913,36 @@ load_image (const gchar  *filename,
         }
     }
 
+  if(image->color_space == OPJ_CLRSPC_GRAY)
+    {
+      base_type = GIMP_GRAY;
+      image_type = GIMP_GRAY_IMAGE;
+    }
+  else
+    {
+      base_type = GIMP_RGB;
+      image_type = GIMP_RGB_IMAGE;
+    }
+
   num_components = image->numcomps;
 
+  if(num_components == 2)
+    {
+      image_type = GIMP_GRAYA_IMAGE;
+    }
+  else if(num_components == 4)
+    {
+      image_type = GIMP_RGBA_IMAGE;
+    }
+
   /* FIXME */
-  base_type = GIMP_GRAY;
+/*  base_type = GIMP_GRAY;
   base_type = GIMP_RGB;
   image_type = GIMP_GRAYA_IMAGE;
   image_type = GIMP_GRAY_IMAGE;
   image_type = GIMP_RGBA_IMAGE;
   image_type = GIMP_RGB_IMAGE;
-
+*/
   width = image->comps[0].w;
   height = image->comps[0].h;
 
@@ -940,6 +960,40 @@ load_image (const gchar  *filename,
   buffer = gimp_drawable_get_buffer (layer_ID);
 
   pixels = malloc (width * num_components);
+
+  for (i = 0; i < height; i++)
+    {
+      for( j = 0; j < num_components; j++)
+        {
+          const int channel_prec = 8;
+
+          OPJ_UINT32 component_prec = image->comps[j].prec;
+
+          if(component_prec >= channel_prec)
+            {
+              int shift = component_prec - channel_prec;
+
+              for( k = 0; k < width; k++)
+                {
+                  pixels[k * num_components + j] = image->comps[j].data[i * width + k] >> shift; 
+                }
+            }
+          else
+            {
+              int mult = 1 << (channel_prec - component_prec);
+
+              for( k = 0; k < width; k++)
+                {
+                  pixels[k* num_components + j] = image->comps[j].data[i * width + k ] * mult; 
+                }
+
+            }
+        }
+
+        gegl_buffer_set (buffer, GEGL_RECTANGLE (0, i, width, 1), 0,
+                       NULL, pixels, GEGL_AUTO_ROWSTRIDE);
+    }
+
 #if 0
   matrix = jas_matrix_create (1, width);