Beefy Boxes and Bandwidth Generously Provided by pair Networks
good chemistry is complicated,
and a little bit messy -LW

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??


Running parallel is possible for both examples. The latter makes use of relay (for orderly) and gather capabilities in MCE.

First Example

use strict; use warnings; use GD::Simple; use MCE::Map; my $png = GD::Image->newFromPng('test.png'); my ($width,$height) = $png->getBounds; MCE::Map->init( max_workers => 4 ); my @sw = mce_map { my ($y,$str) = ($_,''); for my $x (0..$width - 1) { $str .= getPixel($x,$y); } $str; } 0..$height - 1; MCE::Map->finish(); # print $_, "\n" for @sw; sub getPixel { my ($index) = $png->getPixel($_[0],$_[1]); my ($r,$g,$b) = $png->rgb($index); my $p = ($b > 128 || $r > 128) ? 0 : 1; return $p; }

Second Example

use strict; use warnings; use GD::Simple; use MCE; my $png = GD::Image->newFromPng('test.png'); my ($bx,$by) = $png->getBounds; my @col; # foreground colors for (0..$png->colorsTotal) { my ($r,$g,$b) = $png->rgb($_); push (@col,$_) unless ($b>128 || $r>128); } my $pdata = ''; MCE->new( max_workers => 4, chunk_size => 1, input_data => \@col, init_relay => 1, # loads MCE::Relay gather => sub { # this runs inside the parent $pdata |= $_[0]; }, user_func => sub { # run parallel my $val = ~$png->wbmp($_); # send the val to the parent process # relay makes it run serially and orderly MCE::relay { MCE->gather($val); }; } )->run(); our $zlen = int(($bx + 7) / 8); # number of Bytes per line my $pos = 6; my $y = 0; # position after Header of WBMP my @sw; while ($pos < length($pdata)) { $sw[$y] = ''; for (1..$zlen) { # convert binary data into string $sw[$y] .= sprintf("%08b",ord(substr($pdata,$pos++,1))); } # print $sw[$y], "\n"; $y++; }

The examples run well. Output matches the OP's non-parallel demonstrations.

Regards, Mario

In reply to Re: working with png data by marioroy
in thread working with png data by Anonymous Monk

Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":

  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.
  • Log In?

    What's my password?
    Create A New User
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others surveying the Monastery: (7)
    As of 2019-11-12 21:11 GMT
    Find Nodes?
      Voting Booth?
      Strict and warnings: which comes first?

      Results (66 votes). Check out past polls.