Twip

For the podcast, see This Week in Photography. For the austenitic steel, see TWIP steel.

A twip (abbreviating "twentieth of a point", "twentieth of an inch point", or "twentieth of an Imperial point" ) is a typographical measurement, defined as 1/20 of a typographical point. One twip is 1/1440 inch or 17.639 µm when derived from the PostScript point at 72 to the inch, and 1/1445.4 inch or 17.573 µm based on the printer's point at 72.27 to the inch.

In computing

Twips are screen-independent units to ensure that the proportion of screen elements are the same on all display systems. A twip is defined as being 1/1440 of an inch.

A pixel is a screen-dependent unit, standing for 'picture element'. A pixel is a dot that represents the smallest graphical measurement on a screen. Twips are the default unit of measurement in Visual Basic (version 6 and earlier, prior to VB.NET). Converting between twips and screen pixels is achieved using functions such as TwipsPerPixelX and TwipsPerPixelY.

Twips are a commonly used unit with Symbian OS bitmap images and are also used internally in SWF format. They are also used in Rich Text Format from Microsoft for platform-independent exchange and they are the base length unit in OpenOffice.org and its fork LibreOffice.

Flash internally calculates anything that uses pixels with twips (or 1/20 of a point). Sprites, movie clips and any other object on the stage are positioned with twips. As a result, the coordinates of (for example) sprites are always multiples of 0.05 (i.e. 1/20).

See also

• Himetric

References

• Sparke, Gerard; Etherington, Stephen (2000). Visual Basic Programmers' Workbook. ISBN 978-1-74009-445-0.
• MSDN Library — com.ms.wfc.ui.CoordinateSystem.TWIP
• Free On-Line Dictionary of Computing — twip
• Foundation, ActionScript 3.0 Animation, Making Things Move! by Keith Peters ISBN 978-1-59059-791-0 (pbk)
• Converting between twips and pixels - Ruby code