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Diffstat (limited to 'basegfx/inc/basegfx/tools/tools.hxx')
-rw-r--r-- | basegfx/inc/basegfx/tools/tools.hxx | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/basegfx/inc/basegfx/tools/tools.hxx b/basegfx/inc/basegfx/tools/tools.hxx new file mode 100644 index 000000000000..1e33ccbbf995 --- /dev/null +++ b/basegfx/inc/basegfx/tools/tools.hxx @@ -0,0 +1,134 @@ +/************************************************************************* + * + * 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: tools.hxx,v $ + * $Revision: 1.4 $ + * + * 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 */ |