PNGOUT is a

freeware Freeware is software, most often proprietary, that is distributed at no monetary cost to the end user. There is no agreed-upon set of rights, license, or EULA that defines ''freeware'' unambiguously; every publisher defines its own rules for t ...

command line A command-line interpreter or command-line processor uses a command-line interface (CLI) to receive commands from a user in the form of lines of text. This provides a means of setting parameters for the environment, invoking executables and pro ...

optimizer for PNG images written by

Ken Silverman Ken Silverman (born November 1, 1975) is an American game programmer, best known for writing the Build engine. It was most notably utilized by ''Duke Nukem 3D'', ''Shadow Warrior'', ''Blood'', and more than a dozen other games in the mid- to la ...

. The transformation is

lossless Lossless compression is a class of data compression that allows the original data to be perfectly reconstructed from the compressed data with no loss of information. Lossless compression is possible because most real-world data exhibits statistic ...

, meaning that the resulting image is visually identical to the source image. According to its author, this program can often get higher compression than other optimizers by 5–10%. It is possible to compress some inflated PNGs to a size below 1% of the original file. PNGOUT was also available as a plug-in for the

image viewer An image viewer or image browser is a computer program that can display stored graphical images; it can often handle various graphics file formats. Such software usually renders the image according to properties of the display such as color depth, ...

IrfanView IrfanView () is an image viewer, editor, organiser and converter program for Microsoft Windows. It can also play video and audio files, and has some image creation and painting capabilities. IrfanView is free for non-commercial use; commercial u ...

and can be enabled as an option when saving files. It allows editing of various PNGOUT settings via a

dialog box The dialog box (also called dialogue box (non-U.S. English), message box or simply dialog) is a graphical control element in the form of a small window that communicates information to the user and prompts them for a response. Dialog boxes ar ...

. PNGOUT integration was removed in IrfanView version 4.58. In 2006, a commercial version of PNGOUT with a graphical user interface, known as PNGOUTWin, was released by Ardfry Imaging, a small company Silverman co-founded in 2005. There is also a freeware

GUI The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...

frontend to PNGOUT available, known as PNGGauntlet.pnggauntlet.com
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Main operation

The main function of PNGOUT is to reduce the size of image data contained in the IDAT chunk. This chunk is compressed using the deflate algorithm. Deflate algorithms can vary in speed and compression ratio, with higher compression ratios generally implying lower speed. Ken Silverman wrote a deflate compressor for PNGOUT that is slower than the ones used in most graphics software, but produces smaller files. PNGOUT also performs automatic bit depth, color, and palette reduction where appropriate.

External links

Ken Silverman's Utility Page
— official PNGOUT site

PNGOUTWin
— official site
Official Linux/BSD/Mac OS X ports of PNGOUT

References

Freeware Graphics software Data compression software {{graphics-software-stub

Main operation

See also

External links

References