CheatSheetForConvertingto2geom - Revision history

Verbalshadow: add replacement python script

2008-12-30T23:33:50Z

add replacement python script

← Older revision		Revision as of 23:33, 30 December 2008
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	If you are certain that the NR::Rect always contains valid coordinates, replace it with Geom::Rect.		If you are certain that the NR::Rect always contains valid coordinates, replace it with Geom::Rect.

			== Simple One for One Multi-Replacement in a Single Pass Python Script ==

			http://inkscape.pastebin.com/f53b7e2ae

Johanengelen: /* Things that need small adjustments or complete replacement */

2008-12-30T22:32:40Z

Things that need small adjustments or complete replacement

← Older revision		Revision as of 22:32, 30 December 2008
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	<nowiki>'boost::optional<Geom::D2<Geom::Interval> >' requested</nowiki>		<nowiki>'boost::optional<Geom::D2<Geom::Interval> >' requested</nowiki>
	\| <code><nowiki>boost::optional<NR::Rect></nowiki></code>		\| <code><nowiki>boost::optional<NR::Rect></nowiki></code>
	\| <code><nowiki>~~boost::optional<~~Geom::~~Rect>~~</nowiki></code>		\| <code><nowiki>Geom::OptRect</nowiki></code>

	\|-		\|-

Johanengelen: /* Conversion of rectangles (NR::Rect, NRRect, Geom::Rect, Geom::OptRect) */

2008-12-30T22:31:31Z

Conversion of rectangles (NR::Rect, NRRect, Geom::Rect, Geom::OptRect)

← Older revision		Revision as of 22:31, 30 December 2008
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	In summary, it is safest to do the following, but please think carefully about your decision		In summary, it is safest to do the following, but please think carefully about your decision

	NRRect ==> Geom::OptRect		NRRect ==> Geom::OptRect<br>
	NR::Rect ==> Geom::OptRect		NR::Rect ==> Geom::OptRect

	If you are certain that the NR::Rect always contains valid coordinates, replace it with Geom::Rect.		If you are certain that the NR::Rect always contains valid coordinates, replace it with Geom::Rect.

Johanengelen: /* Conversion of rectangles (NR::Rect, NRRect, Geom::Rect, Geom::OptRect) */

2008-12-30T22:31:08Z

Conversion of rectangles (NR::Rect, NRRect, Geom::Rect, Geom::OptRect)

← Older revision		Revision as of 22:31, 30 December 2008
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	Geom::Rect rect4b = *rect4; // rect4b = (1,2)-(3,4)		Geom::Rect rect4b = *rect4; // rect4b = (1,2)-(3,4)
	}		}

			Note that geomrect.isEmpty() does not exist as this name is ambiguous. geomrect.hasZeroArea() does exist, and geomoptrect.isEmpty() too.

			In summary, it is safest to do the following, but please think carefully about your decision

			NRRect ==> Geom::OptRect
			NR::Rect ==> Geom::OptRect

			If you are certain that the NR::Rect always contains valid coordinates, replace it with Geom::Rect.

Johanengelen: /* Conversion of rectangles (NR::Rect, NRRect, Geom::Rect, Geom::OptRect) */

2008-12-30T22:27:46Z

Conversion of rectangles (NR::Rect, NRRect, Geom::Rect, Geom::OptRect)

← Older revision		Revision as of 22:27, 30 December 2008
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	sorry for the very brief text here. feel free to improve it and add things. ask in the jabber channel if you have difficulties.		sorry for the very brief text here. feel free to improve it and add things. ask in the jabber channel if you have difficulties.

	<b>Most of the conversions of NR::Rect and NRRect to 2Geom needs careful thought.</b> 2Geom makes a very important distinction between rectangles and optional rectangles. Libnr is most vague about this, so you often have to find out how a certain rectangle is used: whether it always contains valid data, or whether it can contain wrong data. For example, an NRRect that is defined as (a,b)-(a,b) often means it is an "invalid" rectangle, i.e. the data is invalid and the rectangle coordinates should not be trusted. In this case NRRect::upgrade() returns an empty boost::optional<NR::Rect>. So probably, an NRRect should be replaced with Geom::OptRect. A what? OptRect. Optional Rectangle. This means 2geom knows the data in it can not always be trusted. So when one unifies an OptRect with another OptRect, 2geom checks first whether the coordinates in both can be trusted. An Geom::Rect is <b>always</b> considered as a valid rectangle:		<b>Most of the conversions of NR::Rect and NRRect to 2Geom needs careful thought.</b>

			2Geom makes a very important distinction between rectangles and optional rectangles. Libnr is most vague about this, so you often have to find out how a certain rectangle is used: whether it always contains valid data, or whether it can contain wrong data. For example, an NRRect that is defined as (a,b)-(a,b) often means it is an "invalid" rectangle, i.e. the data is invalid and the rectangle coordinates should not be trusted. In this case NRRect::upgrade() returns an empty boost::optional<NR::Rect>. So probably, an NRRect should be replaced with Geom::OptRect. A what? OptRect. Optional Rectangle. This means 2geom knows the data in it can not always be trusted. So when one unifies an OptRect with another OptRect, 2geom checks first whether the coordinates in both can be trusted. An Geom::Rect is <b>always</b> considered as a valid rectangle:

	Geom::Rect rect1; // will probably be initialized as (0,0)-(0,0), but don't use this! (deprecated)		Geom::Rect rect1; // will probably be initialized as (0,0)-(0,0), but don't use this! (deprecated)

Johanengelen: /* Cheat Sheet For Converting to 2geom */

2008-12-30T22:27:28Z

Cheat Sheet For Converting to 2geom

← Older revision		Revision as of 22:27, 30 December 2008
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	\|}		\|}

			== Conversion of rectangles (NR::Rect, NRRect, Geom::Rect, Geom::OptRect) ==
			sorry for the very brief text here. feel free to improve it and add things. ask in the jabber channel if you have difficulties.

			<b>Most of the conversions of NR::Rect and NRRect to 2Geom needs careful thought.</b> 2Geom makes a very important distinction between rectangles and optional rectangles. Libnr is most vague about this, so you often have to find out how a certain rectangle is used: whether it always contains valid data, or whether it can contain wrong data. For example, an NRRect that is defined as (a,b)-(a,b) often means it is an "invalid" rectangle, i.e. the data is invalid and the rectangle coordinates should not be trusted. In this case NRRect::upgrade() returns an empty boost::optional<NR::Rect>. So probably, an NRRect should be replaced with Geom::OptRect. A what? OptRect. Optional Rectangle. This means 2geom knows the data in it can not always be trusted. So when one unifies an OptRect with another OptRect, 2geom checks first whether the coordinates in both can be trusted. An Geom::Rect is <b>always</b> considered as a valid rectangle:

			Geom::Rect rect1; // will probably be initialized as (0,0)-(0,0), but don't use this! (deprecated)
			Geom::Rect rect2(Geom::Point(1,1), Geom::Point(1,1); // creates (1,1)-(1,1) rect :-)
			Geom::OptRect rect3; // creates rectangle with no coordinates
			Geom::OptRect rect4(Geom::Rect((Geom::Point(1,2), Geom::Point(3,4)); // creates optional rectangle with defined coordinates.
			Geom::Rect rect3b = *rect3; // this will crash, because rect3 does not contain a rect
			//correct usage is:
			if (rect4) {
			Geom::Rect rect4b = *rect4; // rect4b = (1,2)-(3,4)
			}

Johanengelen: /* Items That you Can Switch NR:: for Geom:: */

2008-12-30T22:13:08Z

Items That you Can Switch NR:: for Geom::

← Older revision		Revision as of 22:13, 30 December 2008
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	* <code>NR::Y</code>		* <code>NR::Y</code>
	* <code>NR::X</code>		* <code>NR::X</code>
	* <code>NR::~~identify~~</code>		* <code>NR::identity</code>
	* <code>NR::Coord</code>		* <code>NR::Coord</code>

Johanengelen: /* Lets talk about emptiness. */

2008-12-30T22:12:11Z

Lets talk about emptiness.

← Older revision		Revision as of 22:12, 30 December 2008
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	What is the difference?		What is the difference?

	A Rect that has the coordinates 0f (1,2 - 2,6) ~~has both~~ points and area.		A Rect that has the coordinates of (1,2) - (2,6) contains points and has a non-zero area.
	A Rect that has the coordinates 0f (0,0 - 0,0) has points but no area.		A Rect that has the coordinates of (0,0) - (0,0) contains one point but has zero area.
	A ~~boost::optional::<~~Geom::~~Rect>~~ that has no coordinates has neither points or area.		A Rect that has the coordinates of (0,0) - (10,0) contains points but has zero area.
			A Geom::OptRect that has not been defined with coordinates has neither points or area.

	~~Geom::Rect can~~ not ~~have no coordinates~~ please use ~~boost::optional::<~~Geom::Rect> .		If you need to define a rectangle, but are not sure whether it is always a valid rectangle, please use Geom::OptRect. It means "Optional Rect". A bounding box of a path could be an "invalid" rectangle for example, when the path has no fill or stroke.

	~~rect.isEmpty() checks if~~ a ~~rectangles has coordinates NOT~~ for ~~Area of~~ the ~~rect~~.

			optrect.isEmpty() checks if optrect contains a valid rectangle NOT if the rect has zero area. rect.hasZeroArea() does that.

	==Items That you Can Switch NR:: for Geom::==		==Items That you Can Switch NR:: for Geom::==

Verbalshadow: correction

2008-10-18T05:19:29Z

correction

← Older revision		Revision as of 05:19, 18 October 2008
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	What is the difference?		What is the difference?

	A Rect that has the coordinates 0f (1,2 - 2,6) has both ~~coordinates~~ and area.		A Rect that has the coordinates 0f (1,2 - 2,6) has both points and area.
	A Rect that has the coordinates 0f (0,0 - 0,0) has ~~coordinates~~ but no area.		A Rect that has the coordinates 0f (0,0 - 0,0) has points but no area.
	A boost::optional::<Geom::Rect> that has no coordinates has ~~both~~ points ~~and~~ area.		A boost::optional::<Geom::Rect> that has no coordinates has neither points or area.

	Geom::Rect can not have no coordinates please use boost::optional::<Geom::Rect> .		Geom::Rect can not have no coordinates please use boost::optional::<Geom::Rect> .

Verbalshadow: add comments about types of empties and isEmpty

2008-10-18T05:06:36Z

add comments about types of empties and isEmpty

← Older revision		Revision as of 05:06, 18 October 2008
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	If you are just starting I suggest you pick a header file and convert just one function at a time. That will give you a feel for the process as you get more comfortable do more at one time.		If you are just starting I suggest you pick a header file and convert just one function at a time. That will give you a feel for the process as you get more comfortable do more at one time.

			==Lets talk about emptiness.==
			In Inkscape and in 2geom there are two types of emptiness for rectangles.

			Rectangles with no coordinates.
			Rectangles with zero area.

			What is the difference?

			A Rect that has the coordinates 0f (1,2 - 2,6) has both coordinates and area.
			A Rect that has the coordinates 0f (0,0 - 0,0) has coordinates but no area.
			A boost::optional::<Geom::Rect> that has no coordinates has both points and area.

			Geom::Rect can not have no coordinates please use boost::optional::<Geom::Rect> .

			rect.isEmpty() checks if a rectangles has coordinates NOT for Area of the rect.


	==Items That you Can Switch NR:: for Geom::==		==Items That you Can Switch NR:: for Geom::==