[ViewVC] Diff of: cvs/rxvt-unicode/src/perl/background

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.72 by root, Mon Jul 2 02:01:41 2012 UTC vs.
Revision 1.79 by root, Tue Sep 4 22:41:11 2012 UTC

 #:META:X_RESOURCE:%.border:boolean:respect the terminal border
 #:META:X_RESOURCE:%.interval:seconds:minimum time between updates
 =head1 NAME
-   background - manage terminal background
+background - manage terminal background
 =head1 SYNOPSIS
    urxvt --background-expr 'background expression'
          --background-border
          --background-interval seconds
+=head1 QUICK AND DIRTY CHEAT SHEET
+Just load a random jpeg image and tile the background with it without
+scaling or anything else:
+   load "/path/to/img.jpg"
+The same, but use mirroring/reflection instead of tiling:
+   mirror load "/path/to/img.jpg"
+Load an image and scale it to exactly fill the terminal window:
+   scale keep { load "/path/to/img.jpg" }
+Implement pseudo-transparency by using a suitably-aligned root pixmap
+as window background:
+   rootalign root
+Likewise, but keep a blurred copy:
+   rootalign keep { blur 10, root }
 =head1 DESCRIPTION
 This extension manages the terminal background by creating a picture that
 is behind the text, replacing the normal background colour.
          return load "$HOME/sunday.png";
       }
    }
 This inner expression is evaluated once per hour (and whenever the
-temrinal window is resized). It sets F<sunday.png> as background on
+terminal window is resized). It sets F<sunday.png> as background on
 Sundays, and F<weekday.png> on all other days.
 Fortunately, we expect that most expressions will be much simpler, with
 little Perl knowledge needed.
 width and doubles the image height:
    scale 0.5, 2, load "$HOME/mypic.png"
 IF you try out these expressions, you might suffer from some sluggishness,
-because each time the terminal is resized, it loads the PNG image agin
+because each time the terminal is resized, it loads the PNG image again
 and scales it. Scaling is usually fast (and unavoidable), but loading the
 image can be quite time consuming. This is where C<keep> comes in handy:
    scale 0.5, 2, keep { load "$HOME/mypic.png" }
 left corner of the terminal window)- the result is pseudo-transparency:
 the image seems to be static while the window is moved around.
 =head2 COLOUR SPECIFICATIONS
-Whenever an oprator expects a "colour", then this can be specified in one
+Whenever an operator expects a "colour", then this can be specified in one
 of two ways: Either as string with an X11 colour specification, such as:
    "red"               # named colour
    "#f00"              # simple rgb
    "[50]red"           # red with 50% alpha
          for @_;
       $base
    }
+=back
 =head2 TILING MODES
 The following operators modify the tiling mode of an image, that is, the
 way that pixels outside the image area are painted when the image is used.
    move -TX, -TY, keep { load "mybg.png" }
 =item TW
+=item TH
 Return the width (C<TW>) and height (C<TH>) of the terminal window (the
 terminal window is the full window by default, and the character area only
 when in border-respect mode).
 Using these functions make your expression sensitive to window resizes.
 Clips an image to the given rectangle. If the rectangle is outside the
 image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is
 larger than the image, then the tiling mode defines how the extra pixels
 will be filled.
-If C<$x> an C<$y> are missing, then C<0> is assumed for both.
+If C<$x> and C<$y> are missing, then C<0> is assumed for both.
 If C<$width> and C<$height> are missing, then the window size will be
 assumed.
 Example: load an image, blur it, and clip it to the window size to save
 latter in a white picture.
 Due to idiosyncrasies in the underlying XRender extension, biases less
 than zero can be I<very> slow.
+You can also try the experimental(!) C<muladd> operator.
 =cut
    sub contrast($$;$$;$) {
       my $img = pop;
       my ($r, $g, $b, $a) = @_;
       $a       = 1        if @_ < 4;
       $img = $img->clone;
       $img->brightness ($r, $g, $b, $a);
       $img
+   }
+=item muladd $mul, $add, $img # EXPERIMENTAL
+First multipliesthe pixels by C<$mul>, then adds C<$add>. This cna be used
+to implement brightness and contrast at the same time, with a wider value
+range than contrast and brightness operators.
+Due to numerous bugs in XRender implementations, it can also introduce a
+number of visual artifacts.
+Example: increase contrast by a factor of C<$c> without changing image
+brightness too much.
+   muladd $c, (1 - $c) * 0.5, $img
+=cut
+   sub muladd($$$) {
+      $_[2]->muladd ($_[0], $_[1])
    }
 =item blur $radius, $img
 =item blur $radius_horz, $radius_vert, $img
 C<keep> block so it only is reevaluated as required.
 Putting the blur into a C<keep> block will make sure the blur is only done
 once, while the C<rootalign> is still done each time the window moves.
-   rootlign keep { blur 10, root }
+   rootalign keep { blur 10, root }
 This leaves the question of how to force reevaluation of the block,
 in case the root background changes: If expression inside the block
 is sensitive to some event (root background changes, window geometry
 changes), then it will be reevaluated automatically as needed.
 # compiles a parsed expression
 sub set_expr {
    my ($self, $expr) = @_;
-   $self->{root} = [];
+   $self->{root} = []; # the outermost frame
    $self->{expr} = $expr;
    $self->recalculate;
 }
 # takes a hash of sensitivity indicators and installs watchers
    # set environment to evaluate user expression
    local $self  = $arg_self;
    local $HOME  = $ENV{HOME};
-   local $frame = [];
+   local $frame = $self->{root};
    ($x, $y, $w, $h) = $self->background_geometry ($self->{border});
    # evaluate user expression

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.72 by root, Mon Jul 2 02:01:41 2012 UTC vs. Revision 1.79 by root, Tue Sep 4 22:41:11 2012 UTC

Diff Legend

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.72 by root, Mon Jul 2 02:01:41 2012 UTC vs.
Revision 1.79 by root, Tue Sep 4 22:41:11 2012 UTC