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+/*************************************************************************
+ *
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * Copyright 2000, 2010 Oracle and/or its affiliates.
+ *
+ * OpenOffice.org - a multi-platform office productivity suite
+ *
+ * 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_TOOLS_HXX
+#define _BGFX_TOOLS_TOOLS_HXX
+
+#include <sal/types.h>
+
+namespace basegfx
+{
+ class B2DPoint;
+ class B2DRange;
+
+ namespace tools
+ {
+ /** Liang-Barsky 2D line clipping algorithm
+
+ This function clips a line given by two points against the
+ given rectangle. The resulting line is returned in the
+ given points.
+
+ @param io_rStart
+ Start point of the line. On return, contains the clipped
+ start point.
+
+ @param io_rEnd
+ End point of the line. On return, contains the clipped
+ end point.
+
+ @param rClipRect
+ The rectangle to clip against
+
+ @return true, when at least part of the line is visible
+ after the clip, false otherwise
+ */
+ bool liangBarskyClip2D( ::basegfx::B2DPoint& io_rStart,
+ ::basegfx::B2DPoint& io_rEnd,
+ const ::basegfx::B2DRange& rClipRect );
+
+ /** Expand given parallelogram, such that it extends beyond
+ bound rect in a given direction.
+
+ This method is useful when e.g. generating one-dimensional
+ gradients, such as linear or axial gradients: those
+ gradients vary only in one direction, the other has
+ constant color. Most of the time, those gradients extends
+ infinitely in the direction with the constant color, but
+ practically, one always has a limiting bound rect into
+ which the gradient is painted. The method at hand now
+ extends a given parallelogram (e.g. the transformed
+ bounding box of a gradient) virtually into infinity to the
+ top and to the bottom (i.e. normal to the line io_rLeftTop
+ io_rRightTop), such that the given rectangle is guaranteed
+ to be covered in that direction.
+
+ @attention There might be some peculiarities with this
+ method, that might limit its usage to the described
+ gradients. One of them is the fact that when determining
+ how far the parallelogram has to be extended to the top or
+ the bottom, the upper and lower border are assumed to be
+ infinite lines.
+
+ @param io_rLeftTop
+ Left, top edge of the parallelogramm. Note that this need
+ not be the left, top edge geometrically, it's just used
+ when determining the extension direction. Thus, it's
+ perfectly legal to affine-transform a rectangle, and given
+ the transformed point here. On method return, this
+ parameter will contain the adapted output.
+
+ @param io_rLeftBottom
+ Left, bottom edge of the parallelogramm. Note that this need
+ not be the left, bottom edge geometrically, it's just used
+ when determining the extension direction. Thus, it's
+ perfectly legal to affine-transform a rectangle, and given
+ the transformed point here. On method return, this
+ parameter will contain the adapted output.
+
+ @param io_rRightTop
+ Right, top edge of the parallelogramm. Note that this need
+ not be the right, top edge geometrically, it's just used
+ when determining the extension direction. Thus, it's
+ perfectly legal to affine-transform a rectangle, and given
+ the transformed point here. On method return, this
+ parameter will contain the adapted output.
+
+ @param io_rRightBottom
+ Right, bottom edge of the parallelogramm. Note that this need
+ not be the right, bottom edge geometrically, it's just used
+ when determining the extension direction. Thus, it's
+ perfectly legal to affine-transform a rectangle, and given
+ the transformed point here. On method return, this
+ parameter will contain the adapted output.
+
+ @param rFitTarget
+ The rectangle to fit the parallelogram into.
+ */
+ void infiniteLineFromParallelogram( ::basegfx::B2DPoint& io_rLeftTop,
+ ::basegfx::B2DPoint& io_rLeftBottom,
+ ::basegfx::B2DPoint& io_rRightTop,
+ ::basegfx::B2DPoint& io_rRightBottom,
+ const ::basegfx::B2DRange& rFitTarget );
+
+ }
+}
+
+#endif /* _BGFX_TOOLS_TOOLS_HXX */