term% cat index.txt TWEAK(1) General Commands Manual TWEAK(1)
NAME
tweak - edit bitmap files, subfont files, face files, etc.
SYNOPSIS
tweak [ file ... ]
DESCRIPTION
Tweak edits existing files holding various forms of bitmap images. To
create original images, use art(1) or start from an existing bitmap,
subfont, etc.
Tweak reads its argument files and displays the resulting bitmaps in a
vertical column. If the bitmap is too wide to fit across the display,
it is folded much like a long line of text in an 8½ window. Under
each bitmap is displayed one or two lines of text presenting parameters
of the image. The first line shows the bitmap's ldepth, the log base 2
of the number of bits per pixel; r, the rectangle covered by the image;
and the name of the file from which it was read. If the file is a sub‐
font, a second line presents a hexadecimal 16-bit offset to be applied
to character values from the subfont (typically as stored in a font
file; see font(6)); and the subfont's n, height, and ascent as defined
in cachechars(2).
By means described below, magnified views of portions of the bitmaps
may be displayed. The text associated with such a view includes mag,
the magnification. If the view is of a single character from a sub‐
font, the second line of text shows the character's value (including
the subfont's offset) in hexadecimal and as a character in tweak's de‐
fault font; the character's x, top, bottom, left, and width as defined
in cachechars(2); and iwidth, the physical width of the image in the
subfont's bitmap.
There are two methods to obtain a magnified view of a character from a
subfont. The first is to click mouse button 1 over the image of the
character in the subfont. The second is to select the char entry on
the button 3 menu, point the resulting gunsight cursor at the desired
subfont and click button 3, and then type at the text prompt at the
bottom of the screen the character value, either as a multi-digit hexa‐
decimal number or as a single rune representing the character.
To magnify a portion of other types of bitmap files, click button 1
over the unmagnified file. The cursor will switch to a cross. Still
with button 1, sweep a rectangle, as in 8½, that encloses the portion
of the image to be magnified. (If the file is 16Ã16 or smaller, tweak
will just magnify the entire file; no sweeping is necessary.)
Depressing buttons 1 and 2 within magnified images changes pixel val‐
ues. By default, button 1 sets the pixel to all ones and button 2 sets
the pixel to all zeros.
Across the top of the screen is a textual display of global parameters.
These values, as well as many of the textual values associated with the
images, may be edited by clicking button 1 on the displayed value and
typing a new value. The values along the top of the screen are:
mag Default magnification.
val(hex)
The value used to modify pixels within magnified images. The
value must be in hexadecimal, optionally preceded by a tilde for
bitwise negation.
but1
but2 The boolean function used by the named button to set pixel val‐
ues. The function may be specified either by name as defined in
<libg.h>, e.g. DorS, or by simple boolean expression, e.g.
S|D. In these expressions, S is the pixel value defined above
and D is the pixel being modified.
copy The boolean function used in the copy menu item.
Under button 3 is a menu holding a variety of functions. Many of these
functions prompt for the image upon which to act by switching to a gun‐
sight cursor; click button 3 over the selection, or click a different
button to cancel the action.
open Read and display a file. The name of the file is typed to the
prompt on the bottom line.
read Reread a file.
write Write a file.
copy Use the copy function, default S, to transfer a rectangle of
pixels from one image to another. The program prompts with a
cross cursor; sweep out a rectangle in one image or just click
button 3 to select the whole image. The program will leave that
rectangle in place and attach another one to the cursor. Move
that rectangle to the desired place in any image and click but‐
ton 3, or another button to cancel the action.
char As described above, open a magnified view of a character image
in a subfont.
close Close the specified image. If the image is the unmagnified
file, also close any magnified views of that file.
exit Quit tweak. The program will complain once about modified but
unwritten files.
To clear blocks of pixels, use copy with function 0.
SOURCE
/sys/src/cmd/tweak.c
SEE ALSO
art(1), cachechars(2), bitmap(6), font(6)
TWEAK(1)