add getFields()

and an example program

see #218

Author: jcupitt

CHANGELOG.md

@@ -4,6 +4,8 @@ All notable changes to `:vips` will be documented in this file.
 
 ## master
 
+- add getFields() to fetch an array of field names
+
 ## 2.2.0 - 2023-08-17
 
 - improve FFI startup [West14, jcupitt]

examples/fields.php

@@ -0,0 +1,25 @@
+#!/usr/bin/env php
+<?php
+
+require dirname(__DIR__) . '/vendor/autoload.php';
+
+use Jcupitt\Vips;
+
+$im = Vips\Image::newFromFile($argv[1]);
+
+$names = $im->getFields();
+
+echo "$argv[1]\n";
+foreach ($names as &$name) {
+    $value = $im->get($name);
+    echo "$name: $value\n";
+}
+
+/*
+ * Local variables:
+ * tab-width: 4
+ * c-basic-offset: 4
+ * End:
+ * vim600: expandtab sw=4 ts=4 fdm=marker
+ * vim<600: expandtab sw=4 ts=4
+ */

src/FFI.php

@@ -348,6 +348,7 @@ private static function init(): void
         $glib_decls = $typedefs . <<<EOS
 void* g_malloc (size_t size);
 void g_free (void* data);
+void g_strfreev (char** str_array);
 EOS;
 
         // GObject declarations

src/Image.php

@@ -114,6 +114,8 @@
  * conform to PHP naming conventions, you can use something like
  * `$image->get('ipct-data')`.
  *
+ * Use `$image->getFields()` to get an array of all the possible field names.
+ *
  * Next we have:
  *
  * ```php
@@ -1217,6 +1219,25 @@ public function typeOf(string $name): int
         return $this->getType($name);
     }
 
+    /**
+     * Get the field names available for an image.
+     *
+     * @return Array
+     */
+    public function getFields(): array
+    {
+        $str_array = FFI::vips()->vips_image_get_fields($this->pointer);
+
+        $fields = [];
+        for ($i = 0; $str_array[$i] != null; $i++) {
+            array_push($fields, \FFI::string($str_array[$i]));
+        }
+
+        FFI::glib()->g_free($str_array);
+
+        return $fields;
+    }
+
     /**
      * Set any property on the underlying image.
      *