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authorthb <thb@openoffice.org>2009-10-16 00:43:16 +0200
committerthb <thb@openoffice.org>2009-10-16 00:43:16 +0200
commit1837a267a2cf82b0152631e416d8be66c2adef25 (patch)
treee9df5704754fc1ed559cdc01d7d5c41207af5374 /basegfx/inc/basegfx/tools/keystoplerp.hxx
parent9b9d44ee50a38180c2451ca527bf7b9f6f46f0fe (diff)
#i105937# Much improved gradient support for canvas/basegfx/drawinglayer.
See http://blog.thebehrens.net/2009/07/28/hackweek-iv-canvas-convwatch/ for more background information
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+/*************************************************************************
+ *
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * Copyright 2008 by Sun Microsystems, Inc.
+ *
+ * OpenOffice.org - a multi-platform office productivity suite
+ *
+ * $RCSfile: canvastools.hxx,v $
+ * $Revision: 1.10 $
+ *
+ * This file is part of OpenOffice.org.
+ *
+ * OpenOffice.org is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 3
+ * only, as published by the Free Software Foundation.
+ *
+ * OpenOffice.org 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 Lesser General Public License version 3 for more details
+ * (a copy is included in the LICENSE file that accompanied this code).
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * version 3 along with OpenOffice.org. If not, see
+ * <http://www.openoffice.org/license.html>
+ * for a copy of the LGPLv3 License.
+ *
+ ************************************************************************/
+
+#ifndef _BGFX_TOOLS_KEYSTOPLERP_HXX
+#define _BGFX_TOOLS_KEYSTOPLERP_HXX
+
+#include <basegfx/numeric/ftools.hxx>
+#include <vector>
+
+namespace com{ namespace sun{ namespace star{ namespace uno {
+ template<typename T> class Sequence;
+}}}}
+
+namespace basegfx
+{
+ namespace tools
+ {
+ /** Lerp in a vector of key stops
+
+ This class holds a key stop vector and provides the
+ functionality to lerp inside it. Useful e.g. for
+ multi-stop gradients, or the SMIL key time activity.
+
+ For those, given a global [0,1] lerp alpha, one need to
+ find the suitable bucket index from key stop vector, and
+ then calculate the relative alpha between the two buckets
+ found.
+ */
+ class KeyStopLerp
+ {
+ public:
+ typedef std::pair<std::ptrdiff_t,double> ResultType;
+
+ /** Create lerper with given vector of stops
+
+ @param rKeyStops
+
+ Vector of stops, must contain at least two elements
+ (though preferrably more, otherwise you probably don't
+ need key stop lerping in the first place). All
+ elements must be of monotonically increasing value.
+ */
+ explicit KeyStopLerp( const std::vector<double>& rKeyStops );
+
+ /** Create lerper with given sequence of stops
+
+ @param rKeyStops
+
+ Sequence of stops, must contain at least two elements
+ (though preferrably more, otherwise you probably don't
+ need key stop lerping in the first place). All
+ elements must be of monotonically increasing value.
+ */
+ explicit KeyStopLerp( const ::com::sun::star::uno::Sequence<double>& rKeyStops );
+
+ /** Find two nearest bucket index & interpolate
+
+ @param fAlpha
+ Find bucket index i, with keyStops[i] < fAlpha <=
+ keyStops[i+1]. Return new alpha value in [0,1),
+ proportional to fAlpha's position between keyStops[i]
+ and keyStops[i+1]
+ */
+ ResultType lerp(double fAlpha) const;
+
+ private:
+ std::vector<double> maKeyStops;
+ mutable std::ptrdiff_t mnLastIndex;
+ };
+ }
+}
+
+#endif