LUM(9.1) LUM(9.1)
NAME
lum - compute luminance
SYNOPSIS
fb/lum [ input ]
DESCRIPTION
Lum computes the luminance of the input picture using the NTSC formula L=.299R+.587G+.114B. Pixel values are mapped through the input
image's color map, if any. The resulting image is written to standard output.
SOURCE
/sys/src/fb/lum.c
SEE ALSO
picfile(9.6)
LUM(9.1)
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9V(9.1) 9V(9.1)
NAME
9v, save, flip - copy picture files to and from screen
SYNOPSIS
fb/9v [ -mMq ] [ -w x0 y0 x1 y1 ] [ -c cenx ceny ] [ input ]
fb/save
fb/flip [ -r fps ] [ -p ] p1 p2 ...
DESCRIPTION
9v displays its argument picture file (default standard input) in a new window in the middle of an 81/2 screen. In addition to the native
picfile(9.6) format, it tries to read images of many foreign encodings. (It guesses which encoding based on the file's name, recognizing
suffixes .gif, .jpg, .jpeg, .ega, .face, .pcx, .sgi, .tga, .tif, .tiff, .rle, and .xbm. For a program that guesses based on the file's
contents, see cvt2pic(9.1).) On an 8-bit display, it loads an 8-bit image's color map if it contains one. Otherwise (if the display is
fewer than 8 bits per pixel, or the image is not 8-bit color-mapped) it computes the image's luminance, dithered appropriately for the
available grey shades.
In the 9v window button 1 displays pixel coordinates and values at the top of the window and button 3 pops up a menu. The fix cmap menu
item reloads the color map, in the event that some other program has stepped on it. The exit button exits after confirmation.
The -c flag specifies the window's center coordinates, overriding the default. The -w flag specifies the window's minimum and maximum x
and y coordinates. Flag -m suppresses default loading the color map of images containing one. -M causes 9v to load an image's color map
and exit immediately. -q makes 9v exit on receiving any mouse or keyboard event.
Save writes a picture file containing its window (or screen if 81/2 is not running) onto its standard output.
Flip displays many picture files in sequence in a loop. The pictures must be the same size, and must fit in memory. The pictures are all
loaded into main memory and then sent to the display as required using wrbitmap (see balloc(2)), so the machine running flip can be remote;
a CPU server can be used if there are many large frames. The -r option sets the display rate in frames per second. By default flip dis-
plays as fast as it can: about 15 frames per second for a small picture on a Magnum. The -p flag causes a one-second pause at the end of
the loop.
SOURCE
/sys/src/fb/9v.c
/sys/src/fb/save.c
/sys/src/fb/flip.c
BUGS
9v guesses the format of foreign images by looking at the filename, not its contents.
SEE ALSO
picfile(9.6)
9V(9.1)