PNGOUT
Encyclopedia
PNGOUT is a freeware
command line optimizer for PNG images written by Ken Silverman
. The compression is lossless
, meaning that the resulting image will have exactly the same appearance as the source image. According to its author, this program can often get higher compression than other optimizers by 5–10%.
PNGOUT is also available as a plug-in for the freeware
image viewer
IrfanView
and can be enabled as an option when saving files. It allows editing of various PNGOUT settings via a dialog box
.
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
frontend to PNGOUT available, known as PNGGauntlet.http://pnggauntlet.com/
. In general it requires more processing time to achieve a higher compression ratio. Ken Silverman wrote a new DEFLATE compressor for PNGOUT. It is slower than the ones used in most graphics software, but it produces smaller files. PNGOUT also performs automatic bit depth, color, and palette reduction where appropriate.
Freeware
Freeware is computer software that is available for use at no cost or for an optional fee, but usually with one or more restricted usage rights. Freeware is in contrast to commercial software, which is typically sold for profit, but might be distributed for a business or commercial purpose in the...
command line optimizer for PNG images written by Ken Silverman
Ken Silverman
Ken Silverman is a game programmer, best known for writing the Build engine used in Duke Nukem 3D, Shadow Warrior, Blood, and more than a dozen other games in the mid- to late-1990s...
. The compression is lossless
Lossless data compression
Lossless data compression is a class of data compression algorithms that allows the exact original data to be reconstructed from the compressed data. The term lossless is in contrast to lossy data compression, which only allows an approximation of the original data to be reconstructed, in exchange...
, meaning that the resulting image will have exactly the same appearance as the source image. According to its author, this program can often get higher compression than other optimizers by 5–10%.
PNGOUT is also available as a plug-in for the freeware
Freeware
Freeware is computer software that is available for use at no cost or for an optional fee, but usually with one or more restricted usage rights. Freeware is in contrast to commercial software, which is typically sold for profit, but might be distributed for a business or commercial purpose in the...
image viewer
Image viewer
An image viewer or image browser is a computer program that can display stored graphical image; it can often handle various graphics file formats...
IrfanView
IrfanView
IrfanView is a freeware/shareware image viewer for Microsoft Windows that can view, edit, and convert image files and play video/audio files. It is noted for its small size, speed, ease of use, and ability to handle a wide variety of graphic file formats, and has some image creation and painting...
and can be enabled as an option when saving files. It allows editing of various PNGOUT settings via a dialog box
Dialog box
In a graphical user interface of computers, a dialog box is a type of window used to enable reciprocal communication or "dialog" between a computer and its user. It may communicate information to the user, prompt the user for a response, or both...
.
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
Graphical user interface
In computing, a graphical user interface is a type of user interface that allows users to interact with electronic devices with images rather than text commands. GUIs can be used in computers, hand-held devices such as MP3 players, portable media players or gaming devices, household appliances and...
frontend to PNGOUT available, known as PNGGauntlet.http://pnggauntlet.com/
Main operation
PNGOUT is used mainly 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 ratioData compression ratio
Data compression ratio, also known as compression power, is a computer-science term used to quantify the reduction in data-representation size produced by a data compression algorithm...
. In general it requires more processing time to achieve a higher compression ratio. Ken Silverman wrote a new DEFLATE compressor for PNGOUT. It is slower than the ones used in most graphics software, but it 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
- PNGOUT tutorial by Kerry Watson
- PNGOUTWin — official site
- Official Linux/BSD/Mac OS X ports of PNGOUT