Add enum helper

pyvips/base.py

@@ -1,7 +1,7 @@
 # basic defs and link to ffi
 
 
-from pyvips import ffi, vips_lib, gobject_lib, _to_string, _to_bytes, Error
+from pyvips import ffi, vips_lib, glib_lib, gobject_lib, _to_string, _to_bytes, Error
 
 
 def leak_set(leak):
@@ -89,6 +89,22 @@ def type_map(gtype, fn):
     return vips_lib.vips_type_map(gtype, cb, ffi.NULL, ffi.NULL)
 
 
+def values_for_enum(gtype):
+    """Get all values for a enum (gtype)."""
+
+    g_type_class = gobject_lib.g_type_class_ref(gtype)
+    g_enum_class = ffi.cast('GEnumClass *', g_type_class)
+
+    values = []
+
+    # -1 since we always have a "last" member.
+    for i in range(0, g_enum_class.n_values - 1):
+        value = _to_string(ffi.string(g_enum_class.values[i].value_nick))
+        values.append(value)
+
+    return values
+
+
 __all__ = [
     'leak_set',
     'version',
@@ -100,4 +116,5 @@ def type_map(gtype, fn):
     'type_name',
     'type_map',
     'type_from_name',
+    'values_for_enum'
 ]

pyvips/decls.py

@@ -120,13 +120,15 @@ def cdefs(features):
         GType vips_interpretation_get_type (void);
         GType vips_operation_flags_get_type (void);
         GType vips_band_format_get_type (void);
+        GType vips_token_get_type (void);
+        GType vips_saveable_get_type (void);
+        GType vips_image_type_get_type (void);
 
         typedef struct _GData GData;
 
         typedef struct _GTypeClass GTypeClass;
 
-        typedef struct _GTypeInstance
-        {
+        typedef struct _GTypeInstance {
             GTypeClass *g_class;
         } GTypeInstance;
 
@@ -153,6 +155,24 @@ def cdefs(features):
             unsigned int param_id;
         } GParamSpec;
 
+        typedef struct _GEnumValue {
+            int value;
+
+            const char *value_name;
+            const char *value_nick;
+        } GEnumValue;
+
+        typedef struct _GEnumClass {
+          GTypeClass *g_type_class;
+
+          int minimum;
+          int maximum;
+          unsigned int n_values;
+          GEnumValue *values;
+        } GEnumClass;
+
+        void* g_type_class_ref (GType type);
+
         void g_object_ref (void* object);
         void g_object_unref (void* object);