glenda.party
term% ls -F
term% pwd
$home/manuals/9front/1/tweak
term% cat index.txt
TWEAK(1)                    General Commands Manual                   TWEAK(1)



NAME
       tweak - edit image files, subfont files, face files, etc.

SYNOPSIS
       tweak [ file ...  ]

DESCRIPTION
       Tweak  edits existing files holding various forms of images.  To create
       original images, start from an existing image, subfont, etc.

       Tweak reads its argument files and displays the resulting images  in  a
       vertical  column.   If the image is too wide to fit across the display,
       it is folded much like a long line of text in  an  rio  window.   Under
       each image is displayed one or two lines of text presenting its parame‐
       ters.  The first line shows the image's depth, 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  subfont,  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 images may
       be displayed.  The text associated with such a view includes  mag,  the
       magnification.   If  the  view is of a single character from a subfont,
       the second line of text shows the character's value (including the sub‐
       font's  offset)  in  hexadecimal  and as a character in tweak's default
       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 sub‐
       font's image.

       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 image files, click button 1 over
       the  unmagnified  file.  The cursor will switch to a cross.  Still with
       button 1, sweep a rectangle, as in rio, 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.)

       Pressing buttons 1 and 2 within magnified images changes pixel  values.
       By  default, button 1 sets the pixel to all zeros and button 2 sets the
       pixel to all ones.

       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 pixel value written when the corresponding button is pressed
              over a pixel.

       invert-on-copy
              Whether the pixel values are inverted when a copy  operation  is
              performed.

       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.

       pixels Report the coordinate and value of individual  pixels  indicated
              by  pressing  button 3.  This is a mode of operation canceled by
              pressing button 1 or 2.

       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.

SOURCE
       /sys/src/cmd/tweak.c

SEE ALSO
       cachechars(2), image(6), font(6)

BUGS
       For a program written to adjust width tables in fonts, tweak  has  been
       pushed unreasonably far.



                                                                      TWEAK(1)