[gimp] app: Add some comment documentation to code

[Barak Itkin <barakitkin src gnome org>]

commit 18b9ba1c877be5e259a2ed92c22f3f4a069b4741
Author: Barak Itkin <lightningismyname gmail com>
Date:   Mon Feb 7 03:26:37 2011 +0200

    app: Add some comment documentation to code

 app/core/gimp-units.c        |    4 ++++
 app/core/gimp-user-install.c |    4 ++++
 app/core/gimpimagemap.c      |   16 ++++++++++++++++
 app/core/gimppickable.c      |    6 ++++++
 app/core/gimptemplate.c      |    3 +++
 app/core/gimpunit.c          |    4 ++++
 app/tools/gimpimagemaptool.c |    7 +++++++
 7 files changed, 44 insertions(+), 0 deletions(-)
---
diff --git a/app/core/gimp-units.c b/app/core/gimp-units.c
index 099ff2d..599dbbd 100644
--- a/app/core/gimp-units.c
+++ b/app/core/gimp-units.c
@@ -18,6 +18,10 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+/* This file contains functions to load & save the file containing the
+ * user-defined size units, when the application starts/finished.
+ */
+
 #include "config.h"
 
 #include <glib-object.h>
diff --git a/app/core/gimp-user-install.c b/app/core/gimp-user-install.c
index 17cde5a..20d07f4 100644
--- a/app/core/gimp-user-install.c
+++ b/app/core/gimp-user-install.c
@@ -18,6 +18,10 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+/* This file contains functions to help migrate the settings from a
+ * previous GIMP version to be used with the current (newer) version.
+ */
+
 #include "config.h"
 
 #include <errno.h>
diff --git a/app/core/gimpimagemap.c b/app/core/gimpimagemap.c
index 5904cd4..7a39e3e 100644
--- a/app/core/gimpimagemap.c
+++ b/app/core/gimpimagemap.c
@@ -15,6 +15,22 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+/* This file contains the code necessary for generating on canvas
+ * previews, either by connecting a function to process the pixels or
+ * by connecting a specified GEGL operation to do the processing. It
+ * keeps an undo buffer to allow direct modification of the pixel data
+ * (so that it will show up in the projection) and it will restore the
+ * source in case the mapping procedure was cancelled.
+ *
+ * To create a tool that uses this, see /tools/gimpimagemaptool.c for
+ * the interface and /tools/gimpcolorbalancetool.c for an example of
+ * using that interface.
+ *
+ * Note that when talking about on canvas preview, we are speaking
+ * about non destructive image editing where the operation is previewd
+ * before being applied.
+ */
+
 #include "config.h"
 
 #include <glib-object.h>
diff --git a/app/core/gimppickable.c b/app/core/gimppickable.c
index 83d4909..4fb2e93 100644
--- a/app/core/gimppickable.c
+++ b/app/core/gimppickable.c
@@ -18,6 +18,12 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+/* This file contains an interface for pixel objects that their color at
+ * a given position can be picked. Also included is a utility for
+ * sampling an average area (which uses the implemented picking
+ * functions).
+ */
+
 #include "config.h"
 
 #include <gegl.h>
diff --git a/app/core/gimptemplate.c b/app/core/gimptemplate.c
index 250a1a6..be869c5 100644
--- a/app/core/gimptemplate.c
+++ b/app/core/gimptemplate.c
@@ -18,6 +18,9 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+/* This file contains the definition of the image template objects.
+ */
+
 #include "config.h"
 
 #include <gegl.h>
diff --git a/app/core/gimpunit.c b/app/core/gimpunit.c
index 8d904ac..fad1c5f 100644
--- a/app/core/gimpunit.c
+++ b/app/core/gimpunit.c
@@ -18,6 +18,10 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+/* This file contains the definition of the size unit objects. The
+ * factor of the units is relative to inches (which have a factor of 1).
+ */
+
 #include "config.h"
 
 #include <glib-object.h>
diff --git a/app/tools/gimpimagemaptool.c b/app/tools/gimpimagemaptool.c
index 67bf4ed..c183f70 100644
--- a/app/tools/gimpimagemaptool.c
+++ b/app/tools/gimpimagemaptool.c
@@ -15,6 +15,13 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+/* This file contains a base class for tools that implement on canvas
+ * preview for non destructive editing. The processing of the pixels can
+ * be done either by a gegl op or by a C function (apply_func).
+ *
+ * For the core side of this, please see /app/core/gimpimagemap.c.
+ */
+
 #include "config.h"
 
 #include <string.h>