[gimp] plug-ins: various fixes and nitpicking to file-webp.

[Jehan Pagès <jehanp src gnome org>]

commit 58e6f6ca35720d96fdc4e5127bcea8453ceaa802
Author: Jehan <jehan girinstud io>
Date:   Mon Nov 14 21:27:27 2016 +0100

    plug-ins: various fixes and nitpicking to file-webp.
    
    - get_preset_from_id() was defined in file-webp-dialog.c but used in
      file-webp.c only. Move it there.
    - Make the preset list available in file-webp-save.h header (since it
      is specifically an encoder attribute) as static, because it is used
      both in the dialog ("preset" choice list) and the main file (for match
      of the "preset" parameter as internal ID to a WebPPreset when run as
      non-interactive).
    - Generate the "preset" parameter description from the preset list.
      This way, even if this list were to change (in some hypothetical
      future), the description (and in particular the list of possible
      values and their int match) won't end up wrong.
    - "enum WebPPreset" is typedef-ed to "WebPPreset".
    - Use G_N_ELEMENTS to compute length of arrays on the stack (equivalent
      to the current code but shorter and simpler to read).
    - Many formatting fixes.

 plug-ins/file-webp/file-webp-dialog.c |   50 +++++++++---------------------
 plug-ins/file-webp/file-webp-save.c   |    8 ++--
 plug-ins/file-webp/file-webp-save.h   |   20 +++++++++++-
 plug-ins/file-webp/file-webp.c        |   54 ++++++++++++++++++++++++++++-----
 4 files changed, 83 insertions(+), 49 deletions(-)
---
diff --git a/plug-ins/file-webp/file-webp-dialog.c b/plug-ins/file-webp/file-webp-dialog.c
index a99e067..2d24b77 100644
--- a/plug-ins/file-webp/file-webp-dialog.c
+++ b/plug-ins/file-webp/file-webp-dialog.c
@@ -29,50 +29,30 @@
 
 #include "libgimp/stdplugins-intl.h"
 
-static GtkWidget*     new_combo_from_presets (enum WebPPreset *preset);
-static void           preset_update (GimpIntComboBox* combo_box,
-                                     gpointer data);
-static void           save_dialog_toggle_scale   (GtkWidget  *widget,
-                                                  gpointer   data);
+static void        preset_update            (GimpIntComboBox *combo_box,
+                                             gpointer         data);
+static GtkWidget * new_combo_from_presets   (WebPPreset      *preset);
+static void        save_dialog_toggle_scale (GtkWidget       *widget,
+                                             gpointer         data);
 
-static const struct
-{
-  const enum WebPPreset preset;
-  const gchar *label;
-} presets[] =
-{
-  { WEBP_PRESET_DEFAULT, "Default" },
-  { WEBP_PRESET_PICTURE, "Picture" },
-  { WEBP_PRESET_PHOTO,   "Photo"   },
-  { WEBP_PRESET_DRAWING, "Drawing" },
-  { WEBP_PRESET_ICON,    "Icon"    },
-  { WEBP_PRESET_TEXT,    "Text"    },
-};
-
-
-WebPPreset
-get_preset_from_id (gint id)
-{
-  if (id >= 0 && id < sizeof (presets) / sizeof (presets[0]))
-    return presets[id].preset;
-  return presets[0].preset;
-}
 
 static void
-preset_update (GimpIntComboBox* combo_box, gpointer data) {
+preset_update (GimpIntComboBox *combo_box,
+               gpointer         data)
+{
   if (! gimp_int_combo_box_get_active (combo_box, (gint*) data))
-    * (enum WebPPreset*) data = WEBP_PRESET_DEFAULT;
+    * (WebPPreset*) data = WEBP_PRESET_DEFAULT;
 }
 
-static GtkWidget*
-new_combo_from_presets (enum WebPPreset *preset)
+static GtkWidget *
+new_combo_from_presets (WebPPreset *preset)
 {
   gint i;
   GtkWidget* combo = g_object_new (GIMP_TYPE_INT_COMBO_BOX, NULL);
-  for (i = 0; i < sizeof (presets) / sizeof( presets[0] ); ++i)
-    gimp_int_combo_box_append (GIMP_INT_COMBO_BOX(combo),
-                               GIMP_INT_STORE_VALUE, (gint) presets[i].preset,
-                               GIMP_INT_STORE_LABEL, presets[i].label,
+  for (i = 0; i < G_N_ELEMENTS (webp_presets); ++i)
+    gimp_int_combo_box_append (GIMP_INT_COMBO_BOX (combo),
+                               GIMP_INT_STORE_VALUE, (gint) webp_presets[i].preset,
+                               GIMP_INT_STORE_LABEL, webp_presets[i].label,
                                -1);
   gimp_int_combo_box_connect (GIMP_INT_COMBO_BOX (combo), *preset,
                               G_CALLBACK (preset_update), preset);
diff --git a/plug-ins/file-webp/file-webp-save.c b/plug-ins/file-webp/file-webp-save.c
index fb667a6..a292f31 100644
--- a/plug-ins/file-webp/file-webp-save.c
+++ b/plug-ins/file-webp/file-webp-save.c
@@ -298,7 +298,7 @@ save_layer (const gchar    *filename,
                                                                  &icc_data_size);
                   chunk.bytes = icc_data;
                   chunk.size = icc_data_size;
-                  WebPMuxSetChunk(mux, "ICCP", &chunk, 1);
+                  WebPMuxSetChunk (mux, "ICCP", &chunk, 1);
                   g_object_unref (profile);
                 }
 
@@ -350,7 +350,7 @@ parse_ms_tag (const gchar *str)
     offset++;
 
   if (offset >= length)
-    return(-1);
+    return -1;
 
   if (! g_ascii_isdigit (str[++offset]))
     goto find_another_bra;
@@ -364,7 +364,7 @@ parse_ms_tag (const gchar *str)
   while ((offset < length) && (g_ascii_isdigit (str[offset])));
 
   if (length - offset <= 2)
-    return(-3);
+    return -3;
 
   if ((g_ascii_toupper (str[offset])     != 'M') ||
       (g_ascii_toupper (str[offset + 1]) != 'S'))
@@ -635,7 +635,7 @@ save_image (const gchar    *filename,
   if (nLayers == 0)
     return FALSE;
 
-  g_printerr("Saving WebP file %s\n", filename);
+  g_printerr ("Saving WebP file %s\n", filename);
 
   if (nLayers == 1)
     {
diff --git a/plug-ins/file-webp/file-webp-save.h b/plug-ins/file-webp/file-webp-save.h
index bf3b2bc..e8a3aff 100644
--- a/plug-ins/file-webp/file-webp-save.h
+++ b/plug-ins/file-webp/file-webp-save.h
@@ -26,7 +26,7 @@
 
 typedef struct
 {
-  enum WebPPreset preset;
+  WebPPreset      preset;
   gboolean        lossless;
   gboolean        animation;
   gboolean        loop;
@@ -39,7 +39,23 @@ typedef struct
   gboolean        force_delay;
 } WebPSaveParams;
 
-WebPPreset  get_preset_from_id (gint id);
+static const struct
+{
+  const WebPPreset  preset;
+  const gchar      *label;
+} webp_presets[] =
+{
+  /* The preset order is used as ID parameter in the PDB save procedure.
+   * So it is important to keep it stable in order not to break any
+   * script. Any new preset should be added to the end.
+   */
+  { WEBP_PRESET_DEFAULT, "Default" },
+  { WEBP_PRESET_PICTURE, "Picture" },
+  { WEBP_PRESET_PHOTO,   "Photo"   },
+  { WEBP_PRESET_DRAWING, "Drawing" },
+  { WEBP_PRESET_ICON,    "Icon"    },
+  { WEBP_PRESET_TEXT,    "Text"    },
+};
 
 gboolean   save_image (const gchar    *filename,
                        gint32          nLayers,
diff --git a/plug-ins/file-webp/file-webp.c b/plug-ins/file-webp/file-webp.c
index 453e3a3..06f7b45 100644
--- a/plug-ins/file-webp/file-webp.c
+++ b/plug-ins/file-webp/file-webp.c
@@ -36,13 +36,14 @@
 #include "libgimp/stdplugins-intl.h"
 
 
-static void   query (void);
-static void   run   (const gchar      *name,
-                     gint              nparams,
-                     const GimpParam  *param,
-                     gint             *nreturn_vals,
-                     GimpParam       **return_vals);
+static void       query              (void);
+static void       run                (const gchar      *name,
+                                      gint              nparams,
+                                      const GimpParam  *param,
+                                      gint             *nreturn_vals,
+                                      GimpParam       **return_vals);
 
+static WebPPreset get_preset_from_id (gint              id);
 
 const GimpPlugInInfo PLUG_IN_INFO =
 {
@@ -74,6 +75,9 @@ set_default_params (WebPSaveParams* params)
 static void
 query (void)
 {
+  gchar *preset_param_desc;
+  gint   i;
+
   static const GimpParamDef load_arguments[] =
   {
     { GIMP_PDB_INT32,  "run-mode",     "Interactive, non-interactive" },
@@ -86,14 +90,14 @@ query (void)
     { GIMP_PDB_IMAGE, "image", "Output image" }
   };
 
-  static const GimpParamDef save_arguments[] =
+  static GimpParamDef save_arguments[] =
   {
     { GIMP_PDB_INT32,    "run-mode",      "Interactive, non-interactive" },
     { GIMP_PDB_IMAGE,    "image",         "Input image" },
     { GIMP_PDB_DRAWABLE, "drawable",      "Drawable to save" },
     { GIMP_PDB_STRING,   "filename",      "The name of the file to save the image to" },
     { GIMP_PDB_STRING,   "raw-filename",  "The name entered" },
-    { GIMP_PDB_INT32,    "preset",        "preset (Default=0, Picture=1, Photo=2, Drawing=3, Icon=4, 
Text=5)" },
+    { GIMP_PDB_INT32,    "preset",        NULL },
     { GIMP_PDB_INT32,    "lossless",      "Use lossless encoding (0/1)" },
     { GIMP_PDB_FLOAT,    "quality",       "Quality of the image (0 <= quality <= 100)" },
     { GIMP_PDB_FLOAT,    "alpha-quality", "Quality of the image's alpha channel (0 <= alpha-quality <= 100)" 
},
@@ -127,6 +131,31 @@ query (void)
                                     "",
                                     "8,string,WEBP");
 
+  /*
+   * "preset" values in the PDB save proc are internal IDs, not
+   * necessarily corresponding to the constants from libwebp (though at
+   * time of writing, they are the same).
+   * Generate the "preset" parameter description from webp_presets, so
+   * that we don't have to edit multiple places if new presets are added
+   * in the future.
+   */
+  preset_param_desc = g_strdup_printf ("WebP encoder preset (%s=0",
+                                       webp_presets[0].label);
+  for (i = 1; i < G_N_ELEMENTS (webp_presets); ++i)
+    {
+      gchar *preset_param;
+      gchar *tmp;
+
+      preset_param = g_strdup_printf (", %s=%d%s", webp_presets[i].label, i,
+                                      i == G_N_ELEMENTS (webp_presets) - 1 ?  ")" : "");
+
+      tmp = preset_param_desc;
+      preset_param_desc = g_strconcat (preset_param_desc, preset_param,
+                                       NULL);
+      g_free (preset_param);
+      g_free (tmp);
+    }
+  save_arguments[5].description = preset_param_desc;
   gimp_install_procedure (SAVE_PROC,
                           "Saves files in the WebP image format",
                           "Saves files in the WebP image format",
@@ -143,6 +172,7 @@ query (void)
 
   gimp_register_file_handler_mime (SAVE_PROC, "image/webp");
   gimp_register_save_handler (SAVE_PROC, "webp", "");
+  g_free (preset_param_desc);
 }
 
 static void
@@ -298,3 +328,11 @@ run (const gchar      *name,
 
   values[0].data.d_status = status;
 }
+
+static WebPPreset
+get_preset_from_id (gint id)
+{
+  if (id >= 0 && id < G_N_ELEMENTS (webp_presets))
+    return webp_presets[id].preset;
+  return webp_presets[0].preset;
+}