[gimp] Some basics of loading and exporting the pass-through mode of layer groups in PSD.

[Alexandre Prokoudine <aprokoudine src gnome org>]

commit 63b041046e5f2034d7aed505b9b0fcc2b61d0496
Author: Alexandre Prokoudine <alexandre prokoudine gmail com>
Date:   Wed Aug 9 01:28:40 2017 +0300

    Some basics of loading and exporting the pass-through mode of layer groups in PSD.
    
    The plug-in is still missing two essential bits:
    
    1) setting blend mode to a layer group;
    2) preserving layer group when exporting to PSD.

 plug-ins/file-psd/psd-save.c |    5 ++++-
 plug-ins/file-psd/psd-util.c |    9 +++++++++
 2 files changed, 13 insertions(+), 1 deletions(-)
---
diff --git a/plug-ins/file-psd/psd-save.c b/plug-ins/file-psd/psd-save.c
index 7388ba2..753f4f0 100644
--- a/plug-ins/file-psd/psd-save.c
+++ b/plug-ins/file-psd/psd-save.c
@@ -280,7 +280,10 @@ psd_lmode_layer (gint32  idLayer,
     case GIMP_LAYER_MODE_HARD_MIX:
       strcpy (psdMode, "hMix");
       break;
-
+    case GIMP_LAYER_MODE_PASS_THROUGH:
+      strcpy (psdMode, "pass");
+      break;
+      
     default:
       {
         const gchar *nick = "?";
diff --git a/plug-ins/file-psd/psd-util.c b/plug-ins/file-psd/psd-util.c
index 53039f2..2f856f6 100644
--- a/plug-ins/file-psd/psd-util.c
+++ b/plug-ins/file-psd/psd-util.c
@@ -615,6 +615,9 @@ psd_to_gimp_blend_mode (const gchar            *psd_mode,
    */
   if (layer_composite) *layer_composite = GIMP_LAYER_COMPOSITE_SRC_ATOP;
 
+  if (g_ascii_strncasecmp (psd_mode, "pass", 4) == 0)           /* Pass through (CS)*/
+      return GIMP_LAYER_MODE_PASS_THROUGH;
+
   if (g_ascii_strncasecmp (psd_mode, "norm", 4) == 0)           /* Normal (ps3) */
     {
       if (layer_composite) *layer_composite = GIMP_LAYER_COMPOSITE_AUTO;
@@ -774,6 +777,11 @@ gimp_to_psd_blend_mode (GimpLayerMode          layer_mode,
 
   switch (layer_mode)
     {
+
+    case GIMP_LAYER_MODE_PASS_THROUGH:
+      psd_mode = g_strndup ("pass", 4);                       /* Pass through (CS) */
+      break;
+
     case GIMP_LAYER_MODE_NORMAL_LEGACY:
       psd_mode = g_strndup ("norm", 4);                       /* Normal (ps3) */
       break;
@@ -984,6 +992,7 @@ gimp_layer_mode_effects_name (GimpLayerMode mode)
     "GRAIN EXTRACT",
     "GRAIN MERGE",
     "COLOR ERASE"
+    "PASS THROUGH"
   };
   static gchar *err_name = NULL;
   if (mode >= 0 && mode <= GIMP_LAYER_MODE_COLOR_ERASE_LEGACY)