GRAPHICS: Implement LarryScale cel scaling algorithm

1 files changed, 82 insertions, 0 deletions

diff --git a/graphics/larryScale.h b/graphics/larryScale.h
new file mode 100644
index 0000000000..0248cdb062
--- /dev/null
+++ b/graphics/larryScale.h
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+/* ScummVM - Graphic Adventure Engine
+*
+* ScummVM is the legal property of its developers, whose names
+* are too numerous to list here. Please refer to the COPYRIGHT
+* file distributed with this source distribution.
+*
+* This program is free software; you can redistribute it and/or
+* modify it under the terms of the GNU General Public License
+* as published by the Free Software Foundation; either version 2
+* of the License, or (at your option) any later version.
+*
+* This program 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 General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with this program; if not, write to the Free Software
+* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+*
+*/
+
+#ifndef GRAPHICS_LARRYSCALE_H
+#define GRAPHICS_LARRYSCALE_H
+
+#include "common/scummsys.h"
+
+namespace Graphics {
+
+/*
+
+LarryScale is a bitmap scaler for cartoon images.
+
+Features:
+
+* Supports arbitrary scaling factors along both axes (but looks best between 50% and 200%).
+* When downscaling: preserves fine details.
+* When upscaling: keeps lines smooth, introducing very few block artifacts.
+* Does not introduce additional colors.
+
+Limitations:
+
+* Lines must not be anti-aliased and should be only one pixel wide.
+* Fills should be flat without gradients.
+
+*/
+
+typedef byte LarryScaleColor;
+
+class RowReader {
+public:
+	virtual const LarryScaleColor *readRow(int y) = 0;
+	virtual ~RowReader() {}
+};
+
+class RowWriter {
+public:
+	virtual void writeRow(int y, const LarryScaleColor *row) = 0;
+	virtual ~RowWriter() {}
+};
+
+/**
+ * @param srcWidth			The width, in pixels, of the original image
+ * @param srcHeight			The height, in pixels, of the original image
+ * @param transparentColor	The transparent color. Used for outline detection.
+ * @param rowReader			An object with a callback method for reading the lines of the original
+ *							image
+ * @param dstWidth			The width, in pixels, of the scaled target image
+ * @param dstHeight			The height, in pixels, of the scaled target image
+ * @param rowWriter			An object with a callback method accepting the lines of the target image
+ */
+void larryScale(
+	int srcWidth, int srcHeight,
+	LarryScaleColor transparentColor,
+	RowReader &rowReader,
+	int dstWidth, int dstHeight,
+	RowWriter &rowWriter
+);
+
+}
+
+#endif