libart 2.3.16

[swftools.git] / lib / art / art_filterlevel.h

diff --git a/lib/art/art_filterlevel.h b/lib/art/art_filterlevel.h
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+/* Libart_LGPL - library of basic graphic primitives
+ * Copyright (C) 1998 Raph Levien
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifndef __ART_FILTERLEVEL_H__
+#define __ART_FILTERLEVEL_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+typedef enum {
+  ART_FILTER_NEAREST,
+  ART_FILTER_TILES,
+  ART_FILTER_BILINEAR,
+  ART_FILTER_HYPER
+} ArtFilterLevel;
+
+/* NEAREST is nearest neighbor. It is the fastest and lowest quality.
+
+   TILES is an accurate simulation of the PostScript image operator
+   without any interpolation enabled; each pixel is rendered as a tiny
+   parallelogram of solid color, the edges of which are implemented
+   with antialiasing. It resembles nearest neighbor for enlargement,
+   and bilinear for reduction.
+
+   BILINEAR is bilinear interpolation. For enlargement, it is
+   equivalent to point-sampling the ideal bilinear-interpolated
+   image. For reduction, it is equivalent to laying down small tiles
+   and integrating over the coverage area.
+
+   HYPER is the highest quality reconstruction function. It is derived
+   from the hyperbolic filters in Wolberg's "Digital Image Warping,"
+   and is formally defined as the hyperbolic-filter sampling the ideal
+   hyperbolic-filter interpolated image (the filter is designed to be
+   idempotent for 1:1 pixel mapping). It is the slowest and highest
+   quality.
+
+   Note: at this stage of implementation, most filter modes are likely
+   not to be implemented.
+
+   Note: cubic filtering is missing from this list, because there isn't
+   much point - hyper is just as fast to implement and slightly better
+   in quality.
+
+*/
+
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif /* __ART_PATHCODE_H__ */