Working with 2Geom FAQ - Revision history

BryceHarrington: Move from Goals page

2018-11-12T00:48:39Z

Move from Goals page

← Older revision		Revision as of 00:48, 12 November 2018
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	== Questions ==		== Questions ==

			=== How do I use the basic geometric primitives? ===
			Point and D2<T> provide the classical two dimensional point. A rectangle is a D2<Interval>, a 2d parametric polynomial is a D2<SBasis>. Most operations are lifted from T automatically, so for example, a matrix multiply applied to a Rect produces the smallest rect that would contain the result.

			Matrix provides a 2D affine transformation(scale, rotate, translate). There is also a NR:Matrix which provides general linear algebra (using blas etc).

			Polynomials (SBasis and Bezier) which can be cheaply transformed between basis. There are many operations on polynomials, ranging from traditional arithmetic (+, -, *, /), through higher functions (sin, sqrt) to geometric operators (unit_vector, curvature).

			There are paths with various operations like intersection and bounding.

			There are special geometric types like Circle, ConvexHull and Ray with optimised representations and operators (intersection, nearest point, roots).


	===How to create a straight line (for types: Path, pwd2, d2pw)?===		===How to create a straight line (for types: Path, pwd2, d2pw)?===

2016-07-13T05:58:37Z

← Older revision	Revision as of 05:58, 13 July 2016
(No difference)

2013-11-26T10:13:52Z

How do I convert 2geom to svgd and back?

← Older revision		Revision as of 10:13, 26 November 2013
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	Above appears out-dated, try:		Above appears out-dated, try:

	#include <~~2geom~~/svg~~-path~~.h>		#include <svg/svg.h>
	...		...
	std::vector<Geom::Path> path_2geom;		std::vector<Geom::Path> path_2geom;

2013-11-26T10:07:07Z

← Older revision		Revision as of 10:07, 26 November 2013
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	g_free(svgd);		g_free(svgd);

			Above appears out-dated, try:

			#include <2geom/svg-path.h>
			...
			std::vector<Geom::Path> path_2geom;
			gchar * svgd = sp_svg_write_path( path_2geom );
			std::vector<Geom::Path> newpath_2geom = sp_svg_read_pathv(svgd)
			g_free(svgd);

	===What does "compose" do?===		===What does "compose" do?===

2012-02-19T20:20:31Z

A dot product ?

← Older revision		Revision as of 20:20, 19 February 2012
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	2Geom provides various compose operations for functions representable using piecewise sbasis functions, as well the ability to compose arbitrary functions defined directly in code. ~~All~~ the mathematics is performed in sbasis space.		2Geom provides various compose operations for functions representable using piecewise sbasis functions, as well the ability to compose arbitrary functions defined directly in code. Almost all the mathematics is performed in sbasis space.

2012-02-19T20:19:53Z

remove obsolete documentation

← Older revision		Revision as of 20:19, 19 February 2012
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	g_free(svgd);		g_free(svgd);


	~~===How do I convert from Inkscape paths to 2geom paths?===~~
	~~#include "live_effects/n-art-bpath-2geom.h"~~
	~~...~~
	~~NArtBpath * path_in;~~
	~~std::vector<Geom::Path> path_2geom = BPath_to_2GeomPath(path_in);~~
	~~NArtBpath *new_bpath = BPath_from_2GeomPath(path_2geom);~~

	~~===How do I convert from Inkscape points to 2geom points?===~~
	~~Geom::Point p_2geom(NR_HUGE, NR_HUGE);~~
	~~NR::Point t(p_2geom);~~
	~~Geom::Point pother_2geom = t.to_2geom();~~

	===What does "compose" do?===		===What does "compose" do?===

2008-08-18T11:19:36Z

How to convert from Path to pwd2 to d2pw to path and back?

← Older revision		Revision as of 11:19, 18 August 2008
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	Piecewise<D2<SBasis> > pwd2 = Piecewise<D2<SBasis> >(D2<SBasis>(Linear(a[X], b[X]), Linear(a[Y], b[Y])));		Piecewise<D2<SBasis> > pwd2 = Piecewise<D2<SBasis> >(D2<SBasis>(Linear(a[X], b[X]), Linear(a[Y], b[Y])));

	===How to convert from Path to pwd2 to d2pw to path and back?===		===How to convert from Path (or PathVector) to pwd2 to d2pw to path and back?===

	D2<Piecewise<SBasis> > y;		D2<Piecewise<SBasis> > y;
	Piecewise<D2<SBasis> > x;		Piecewise<D2<SBasis> > x;
	Path p;		Path p;
			PathVector pvec;
	//Assume the above vars are initialized		//Assume the above vars are initialized
	x = p.toPwSb();		x = p.toPwSb();
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	x = sectionize(y); // d2pw -> pwd2		x = sectionize(y); // d2pw -> pwd2
	p = path_from_piecewise(x, tolerance); // pw2d -> path		p = path_from_piecewise(x, tolerance); // pw2d -> path
			x = paths_to_pw(pvec); // pathvector -> pwd2

	How do i convert from d2pw to path?		How do i convert from d2pw to path?

2008-07-01T17:05:49Z

How to convert from Path to pwd2 to d2pw to path and back?

← Older revision		Revision as of 17:05, 1 July 2008
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	//Assume the above vars are initialized		//Assume the above vars are initialized
	x = p.toPwSb();		x = p.toPwSb();
	y = make_cuts_independant(x); // pwd2 -> d2pw		y = make_cuts_independant(x); // pwd2 -> d2pw
	x = sectionize(y); // d2pw -> pwd2		x = sectionize(y); // d2pw -> pwd2
			p = path_from_piecewise(x, tolerance); // pw2d -> path

	How do i convert from d2pw to path		How do i convert from d2pw to path?
	~~How do i convert from pwd2 to path~~

	===How do I calculate the bounding box of a path?===		===How do I calculate the bounding box of a path?===

2008-04-04T19:45:47Z

dot product

← Older revision		Revision as of 19:45, 4 April 2008
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	* 'center-warp', which shows how repeated composition produces the tweak tool effect		* 'center-warp', which shows how repeated composition produces the tweak tool effect
	* 'path-along-path' which shows how composition allows mapping a shape along a path		* 'path-along-path' which shows how composition allows mapping a shape along a path

			===A dot product ?===
			the dot() function is here for you.
			point1 = Geom::Point(10,2);
			point2 = Geom::Point(0,1);
			dot(point1,point2); // = 2


	2Geom provides various compose operations for functions representable using piecewise sbasis functions, as well the ability to compose arbitrary functions defined directly in code. All the mathematics is performed in sbasis space.		2Geom provides various compose operations for functions representable using piecewise sbasis functions, as well the ability to compose arbitrary functions defined directly in code. All the mathematics is performed in sbasis space.

2007-12-25T09:58:51Z

How do I convert from Inkscape points to 2geom points?

← Older revision		Revision as of 09:58, 25 December 2007
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	===How do I convert from Inkscape points to 2geom points?===		===How do I convert from Inkscape points to 2geom points?===
	Geom::Point p_2geom(NR_HUGE, NR_HUGE);		Geom::Point p_2geom(NR_HUGE, NR_HUGE);
	NR::Point t(~~t_2geom~~);		NR::Point t(p_2geom);
	Geom::Point pother_2geom = t.to_2geom();		Geom::Point pother_2geom = t.to_2geom();