Beefy Boxes and Bandwidth Generously Provided by pair Networks
Do you know where your variables are?

Re: Question about Tk Canvas, pixels, and images

by Dr. Mu (Hermit)
on Apr 09, 2001 at 10:45 UTC ( #70940=note: print w/replies, xml ) Need Help??

in reply to Question about Tk Canvas, pixels, and images

Use Tk::Photo to create a blank image and then the Canvas' createImage method to install it onto the Canvas. Once there, you can manipulate its pixels individually, like this:
use Tk; $mw = Tk::MainWindow->new; $can = $mw->Canvas(-width => 320, -height => 240)->pack(); $img = $mw->Photo(-width => 320, -height => 240, -palette => '256/256/ +256'); $img->blank; $can->createImage(0, 0, -image => $img, -anchor => 'nw'); $img->put(RED, -to => (160, 120)); printf "%6.6X", $img->get(160, 120); MainLoop();
This code puts a red dot in the middle of a transparent image, then reads and outputs its color in hex. The documentation that covers this comes with the ActiveState distribution of Tk, but I'm sure you can find it on the web if you're not using that distro.

Log In?

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://70940]
[ambrus]: ad code examples.
[ambrus]: I'm not trying to recommend PHP, but I think it has way too bad a name because of its past.
[ambrus]: This is different from MS Word, which was already a good editor in the pre-unicode days (in word for windows versions 2 and 6, which ran on windows 3 but also on windows 95), only it wasn't trying to solve the task of writing maths papers back then.
[Discipulus]: ah ok, sounds reasonable; with no fear: Perl all life long
[ambrus]: Mind you, LaTeX is currently still useful for writing math paper or snippet content without styling in such a way that the
[ambrus]: formatting conventions of a journal or website can be quickly applied to it, and MS Office and LibreOffice has not quite solved this (although it's better for this than it used to be),
[ambrus]: which is sort of a drawback compared to the ages of typewritten manuscripts representing content only to which the typesetter applies formatting, but that process required much more manual labor.
[ambrus]: If you want to typeset a manuscript, you can still do much less work then in the manual typesetting ages and get good formatting.
[ambrus]: All with only cheap modern computers and software.
[ambrus]: Something you can have at home and your corner print shop, without a whole printing press's worth of equipment.

How do I use this? | Other CB clients
Other Users?
Others chilling in the Monastery: (12)
As of 2017-09-26 11:12 GMT
Find Nodes?
    Voting Booth?
    During the recent solar eclipse, I:

    Results (293 votes). Check out past polls.