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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.36 by root, Fri Jun 8 20:23:09 2012 UTC vs.
Revision 1.40 by root, Fri Jun 8 22:19:21 2012 UTC

    } else {
       return scale load "$HOME/sunday.png";
    }
 This expression gets evaluated once per hour. It will set F<sunday.png> as
-background on sundays, and F<weekday.png> on all other days.
+background on Sundays, and F<weekday.png> on all other days.
 Fortunately, we expect that most expressions will be much simpler, with
 little Perl knowledge needed.
 Basically, you always start with a function that "generates" an image
 horizontal and vertical dimensions. For example, this halves the image
 width and doubles the image height:
    scale 50, 200, load "$HOME/mypic.png"
-TODO
+Other effects than scalign are also readily available, for exmaple, you can
+tile the image to fill the whole window, instead of resizing it:
+   tile load "$HOME/mypic.png"
+In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator
+is kind of superfluous.
+Another common effect is to mirror the image, so that the same edges touch:
+   mirror load "$HOME/mypic.png"
+This is also a typical background expression:
+   rootalign root
+It first takes a snapshot of the screen background image, and then
+moves it to the upper left corner of the screen - the result is
+pseudo-transparency, as the image seems to be static while the window is
+moved around.
 =head3 CYCLES AND CACHING
-TODO
+As has been mentioned before, the expression might be evaluated multiple
-Each time the expression is reevaluated, a new cycle is said to have begun. Many operators
+times. Each time the expression is reevaluated, a new cycle is said to
-cache their results till the next cycle. For example
+have begun. Many operators cache their results till the next cycle.
+For example, the C<load> operator keeps a copy of the image. If it is
+asked to load the same image on the next cycle it will not load it again,
+but return the cached copy.
+This only works for one cycle though, so as long as you load the same
+image every time, it will always be cached, but when you load a different
+image, it will forget about the first one.
+This allows you to either speed things up by keeping multiple images in
+memory, or comserve memory by loading images more often.
+For example, you can keep two images in memory and use a random one like
+this:
+   my $img1 = load "img1.png";
+   my $img2 = load "img2.png";
+   (0.5 > rand) ? $img1 : $img2
+Since both images are "loaded" every time the expression is evaluated,
+they are always kept in memory. Contrast this version:
+   my $path1 = "img1.png";
+   my $path2 = "img2.png";
+   load ((0.5 > rand) ? $path1 : $path2)
+Here, a path is selected randomly, and load is only called for one image,
+so keeps only one image in memory. If, on the next evaluation, luck
+decides to use the other path, then it will have to load that image again.
 =head2 REFERENCE
 =head3 COMMAND LINE SWITCHES
 replaces the background of the character area.
 =back
 =cut
-our $EXPR;#d#
-#$EXPR = 'move W * 0.1, -H * 0.1, resize W * 0.5, H * 0.5, repeat_none load "opensource.png"';
-$EXPR = 'move -TX, -TY, load "argb.png"';
-#$EXPR = '
-#   rotate W, H, 50, 50, counter 1/59.95, repeat_mirror,
-#   clip X, Y, W, H, repeat_mirror,
-#   load "/root/pix/das_fette_schwein.jpg"
-#';
-#$EXPR = 'solid "red"';
-#$EXPR = 'blur root, 10, 10'
-#$EXPR = 'blur move (root, -x, -y), 5, 5'
-#resize load "/root/pix/das_fette_schwein.jpg", w, h
 our $HOME;
 our ($self, $old, $new);
 our ($x, $y, $w, $h);
 =item solid $width, $height, $colour
 Creates a new image and completely fills it with the given colour. The
 image is set to tiling mode.
-If <$width> and C<$height> are omitted, it creates a 1x1 image, which is
+If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
 useful for solid backgrounds or for use in filtering effects.
 =cut
    sub solid($$;$) {
 =item contrast $r, $g, $b, $a, $img
 Adjusts the I<contrast> of an image.
+#TODO#
 =item brightness $factor, $img
 =item brightness $r, $g, $b, $img
 =item brightness $r, $g, $b, $a, $img
+Adjusts the brightness of an image.
 =cut
    sub contrast($$;$$;$) {
       my $img = pop;
       ($g, $b) = ($r, $r) if @_ < 4;
       $a       = 1        if @_ < 5;
       $img = $img->clone;
-#      $img->contrast ($r, $g, $b, $a);
+      $img->contrast ($r, $g, $b, $a);
       $img
    }
    sub brightness($$;$$;$) {
       my $img = pop;
       $img = $img->clone;
       $img->brightness ($r, $g, $b, $a);
       $img
    }
+=item blur $radius, $img
+=item blur $radius_horz, $radius_vert, $img
+Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
+can also be specified separately.
+Blurring is often I<very> slow, at least compared or other
+operators. Larger blur radii are slower than smaller ones, too, so if you
+don't want to freeze your screen for long times, start experimenting with
+low values for radius (<5).
+=cut
    sub blur($$;$) {
       my $img = pop;
       $img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
    }
+=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
+Rotates the image by C<$degrees> degrees, counter-clockwise, around the
+pointer at C<$center_x> and C<$center_y> (specified as percentage of image
+width/height), generating a new image with width C<$new_width> and height
+C<$new_height>.
+#TODO# new width, height, maybe more operators?
+Example: rotate the image by 90 degrees
+=cut
    sub rotate($$$$$$) {
       my $img = pop;
       $img->rotate (
          $_[0],

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.36 by root, Fri Jun 8 20:23:09 2012 UTC vs. Revision 1.40 by root, Fri Jun 8 22:19:21 2012 UTC

Diff Legend

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.36 by root, Fri Jun 8 20:23:09 2012 UTC vs.
Revision 1.40 by root, Fri Jun 8 22:19:21 2012 UTC