easier array arg creation

added stdarg array double creator, used the _new as well, small other
fixes

libvips/arithmetic/linear.c

@@ -280,19 +280,10 @@ vips_linearv( VipsImage *in, VipsImage **out,
 {
 	VipsArea *area_a;
 	VipsArea *area_b;
-	double *array; 
 	int result;
-	int i;
 
-	area_a = vips_area_new_array( G_TYPE_DOUBLE, sizeof( double ), n ); 
-	array = (double *) area_a->data;
-	for( i = 0; i < n; i++ ) 
-		array[i] = a[i];
-
-	area_b = vips_area_new_array( G_TYPE_DOUBLE, sizeof( double ), n ); 
-	array = (double *) area_b->data;
-	for( i = 0; i < n; i++ ) 
-		array[i] = b[i];
+	area_a = (VipsArea *) vips_array_double_new( a, n );
+	area_b = (VipsArea *) vips_array_double_new( b, n );
 
 	result = vips_call_split( "linear", ap, in, out, area_a, area_b );
 
@@ -306,8 +297,8 @@ vips_linearv( VipsImage *in, VipsImage **out,
  * vips_linear:
  * @in: image to transform
  * @out: output image
- * @a: array of constants for multiplication
- * @b: array of constants for addition
+ * @a: (array length=n): array of constants for multiplication
+ * @b: (array length=n): array of constants for addition
  * @n: length of constant arrays
  * @...: %NULL-terminated list of optional named arguments
  *

libvips/deprecated/vips7compat.c

@@ -2147,14 +2147,10 @@ im_rightshift_size( IMAGE *in, IMAGE *out,
 int 
 im_Lab2XYZ_temp( IMAGE *in, IMAGE *out, double X0, double Y0, double Z0 )
 {
-	double ary[3];
 	VipsArea *temp;
 	VipsImage *x;
 
-	ary[0] = X0;
-	ary[1] = Y0;
-	ary[2] = Z0;
-	temp = (VipsArea *) vips_array_double_new( ary, 3 ); 
+	temp = (VipsArea *) vips_array_double_newv( 3, X0, Y0, Z0 ); 
 	if( vips_Lab2XYZ( in, &x, "temp", temp, NULL ) ) {
 		vips_area_unref( temp );
 		return( -1 );

libvips/foreign/dzsave.c

@@ -569,6 +569,10 @@ strip_allocate( VipsThreadState *state, void *a, gboolean *stop )
 
 	VipsRect image;
 
+#ifdef DEBUG
+	printf( "strip_allocate\n" );
+#endif /*DEBUG*/
+
 	image.left = 0;
 	image.top = 0;
 	image.width = layer->width;
@@ -589,6 +593,10 @@ strip_allocate( VipsThreadState *state, void *a, gboolean *stop )
 
 	if( vips_rect_isempty( &state->pos ) ) {
 		*stop = TRUE;
+#ifdef DEBUG
+		printf( "strip_allocate: done\n" );
+#endif /*DEBUG*/
+
 		return( 0 );
 	}
 
@@ -703,6 +711,10 @@ strip_work( VipsThreadState *state, void *a )
 	VipsImage *x;
 	char buf[PATH_MAX];
 
+#ifdef DEBUG
+	printf( "strip_work\n" );
+#endif /*DEBUG*/
+
 	if( tile_name( layer, buf, 
 		state->x / dz->tile_size, state->y / dz->tile_size ) )
 		return( -1 );
@@ -732,12 +744,20 @@ strip_work( VipsThreadState *state, void *a )
 		x = z;
 	}
 
+#ifdef DEBUG
+	printf( "strip_work: writing to %s\n", buf );
+#endif /*DEBUG*/
+
 	if( vips_image_write_to_file( x, buf ) ) {
 		g_object_unref( x );
 		return( -1 );
 	}
 	g_object_unref( x );
 
+#ifdef DEBUG
+	printf( "strip_work: success\n" );
+#endif /*DEBUG*/
+
 	return( 0 );
 }
 

libvips/include/vips/object.h

@@ -339,6 +339,28 @@ int vips_object_get_argument_priority( VipsObject *object, const char *name );
 #define VIPS_ARGUMENT_FOR_ALL_END } }
 
 /* And some macros to collect args from a va list. 
+ *
+ * Use something like this:
+
+	GParamSpec *pspec;
+	VipsArgumentClass *argument_class;
+	VipsArgumentInstance *argument_instance;
+
+	if( vips_object_get_argument( VIPS_OBJECT( operation ), name,
+		&pspec, &argument_class, &argument_instance ) )
+		return( -1 );
+
+	VIPS_ARGUMENT_COLLECT_SET( pspec, argument_class, ap );
+
+		GValue value holds the value of an input argument, do 
+		something with it
+
+	VIPS_ARGUMENT_COLLECT_GET( pspec, argument_class, ap );
+
+		void **arg points to where to write an output argument
+
+	VIPS_ARGUMENT_COLLECT_END
+ 
  */
 #define VIPS_ARGUMENT_COLLECT_SET( PSPEC, ARG_CLASS, AP ) \
 	if( (ARG_CLASS->flags & VIPS_ARGUMENT_INPUT) ) { \

libvips/include/vips/type.h

@@ -137,6 +137,7 @@ GType vips_blob_get_type( void );
 #define VIPS_TYPE_ARRAY_DOUBLE (vips_array_double_get_type())
 typedef VipsArea VipsArrayDouble;
 VipsArrayDouble *vips_array_double_new( const double *array, int n );
+VipsArrayDouble *vips_array_double_newv( int n, ... );
 GType vips_array_double_get_type( void );
 
 /**

libvips/iofuncs/object.c

@@ -43,6 +43,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <stdarg.h>
 
 #include <vips/vips.h>
 #include <vips/internal.h>

libvips/iofuncs/type.c

@@ -46,6 +46,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <stdarg.h>
 
 #include <vips/vips.h>
 #include <vips/internal.h>
@@ -135,7 +136,7 @@ vips_thing_get_type( void )
  * function. It also keeps a count and a GType, so the area can be an array.
  *
  * This type is used for things like passing an array of double or an array of
- * VipsObject pointers to operations, and for reference-countred immutable
+ * VipsObject pointers to operations, and for reference-counted immutable
  * strings. 
  */
 
@@ -939,6 +940,37 @@ vips_array_double_new( const double *array, int n )
 	return( area );
 }
 
+/**
+ * vips_array_double_newv:
+ * @n: number of doubles
+ * @...: list of double arguments
+ *
+ * Allocate a new array of @n doubles and copy @... into it. Free with
+ * vips_area_unref().
+ *
+ * See also: vips_array_double_new()
+ *
+ * Returns: (transfer full): A new #VipsArrayDouble.
+ */
+VipsArrayDouble *
+vips_array_double_newv( int n, ... )
+{
+	va_list ap;
+	VipsArea *area;
+	double *array;
+	int i;
+
+	area = vips_area_new_array( G_TYPE_DOUBLE, sizeof( double ), n );
+	array = vips_area_get_data( area, NULL, NULL, NULL, NULL );
+
+	va_start( ap, n );
+	for( i = 0; i < n; i++ )
+		array[i] = va_arg( ap, double ); 
+	va_end( ap );
+
+	return( area );
+}
+
 /** 
  * vips_value_get_array_double:
  * @value: %GValue to get from