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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.44 by root, Sun Jun 10 11:31:22 2012 UTC vs.
Revision 1.45 by root, Sun Jun 10 11:53:32 2012 UTC

       my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] || 1, $_[1] || 1);
       $img->fill ($colour);
       $img
    }
+=item clone $img
+Returns an exact copy of the image. This is useful if you want to have
+multiple copies of the same image to apply different effects to.
+=cut
+   sub clone($) {
+      $_[0]->clone
+   }
 =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.
+=over 4
+=item tile $img
+Tiles the whole plane with the image and returns this new image - or in
+other words, it returns a copy of the image in plane tiling mode.
+Example: load an image and tile it over the background, without
+resizing. The C<tile> call is superfluous because C<load> already defaults
+to tiling mode.
+   tile load "mybg.png"
+=item mirror $img
+Similar to tile, but reflects the image each time it uses a new copy, so
+that top edges always touch top edges, right edges always touch right
+edges and so on (with normal tiling, left edges always touch right edges
+and top always touch bottom edges).
+Example: load an image and mirror it over the background, avoiding sharp
+edges at the image borders at the expense of mirroring the image itself
+   mirror load "mybg.png"
+=item pad $img
+Takes an image and modifies it so that all pixels outside the image area
+become transparent. This mode is most useful when you want to place an
+image over another image or the background colour while leaving all
+background pixels outside the image unchanged.
+Example: load an image and display it in the upper left corner. The rest
+of the space is left "empty" (transparent or wahtever your compisotr does
+in alpha mode, else background colour).
+   pad load "mybg.png"
+=item extend $img
+Extends the image over the whole plane, using the closest pixel in the
+area outside the image. This mode is mostly useful when you more complex
+filtering operations and want the pixels outside the image to have the
+same values as the pixels near the edge.
+Example: just for curiosity, how does this pixel extension stuff work?
+   extend move 50, 50, load "mybg.png"
+=cut
+   sub pad($) {
+      my $img = $_[0]->clone;
+      $img->repeat_mode (urxvt::RepeatNone);
+      $img
+   }
+   sub tile($) {
+      my $img = $_[0]->clone;
+      $img->repeat_mode (urxvt::RepeatNormal);
+      $img
+   }
+   sub mirror($) {
+      my $img = $_[0]->clone;
+      $img->repeat_mode (urxvt::RepeatReflect);
+      $img
+   }
+   sub extend($) {
+      my $img = $_[0]->clone;
+      $img->repeat_mode (urxvt::RepeatPad);
+      $img
+   }
+=back
-=head2 VARIABLES
+=head2 VARIABLE VALUES
 The following functions provide variable data such as the terminal window
-dimensions. They are not (Perl-) variables, they jsut return stuff that
+dimensions. They are not (Perl-) variables, they just return stuff that
 varies. Most of them make your expression sensitive to some events, for
 example using C<TW> (terminal width) means your expression is evaluated
 again when the terminal is resized.
 =over 4
       $self->{counter} + 0
    }
 =back
-=head2 TILING MODES
+=head2 SHAPE CHANGING OPERATORS
-The following operators modify the tiling mode of an image, that is, the
+The following operators modify the shape, size or position of the image.
-way that pixels outside the image area are painted when the image is used.
 =over 4
-=item tile $img
-Tiles the whole plane with the image and returns this new image - or in
-other words, it returns a copy of the image in plane tiling mode.
-Example: load an image and tile it over the background, without
-resizing. The C<tile> call is superfluous because C<load> already defaults
-to tiling mode.
-   tile load "mybg.png"
-=item mirror $img
-Similar to tile, but reflects the image each time it uses a new copy, so
-that top edges always touch top edges, right edges always touch right
-edges and so on (with normal tiling, left edges always touch right edges
-and top always touch bottom edges).
-Example: load an image and mirror it over the background, avoiding sharp
-edges at the image borders at the expense of mirroring the image itself
-   mirror load "mybg.png"
-=item pad $img
-Takes an image and modifies it so that all pixels outside the image area
-become transparent. This mode is most useful when you want to place an
-image over another image or the background colour while leaving all
-background pixels outside the image unchanged.
-Example: load an image and display it in the upper left corner. The rest
-of the space is left "empty" (transparent or wahtever your compisotr does
-in alpha mode, else background colour).
-   pad load "mybg.png"
-=item extend $img
-Extends the image over the whole plane, using the closest pixel in the
-area outside the image. This mode is mostly useful when you more complex
-filtering operations and want the pixels outside the image to have the
-same values as the pixels near the edge.
-Example: just for curiosity, how does this pixel extension stuff work?
-   extend move 50, 50, load "mybg.png"
-=cut
-   sub pad($) {
-      my $img = $_[0]->clone;
-      $img->repeat_mode (urxvt::RepeatNone);
-      $img
-   }
-   sub tile($) {
-      my $img = $_[0]->clone;
-      $img->repeat_mode (urxvt::RepeatNormal);
-      $img
-   }
-   sub mirror($) {
-      my $img = $_[0]->clone;
-      $img->repeat_mode (urxvt::RepeatReflect);
-      $img
-   }
-   sub extend($) {
-      my $img = $_[0]->clone;
-      $img->repeat_mode (urxvt::RepeatPad);
-      $img
-   }
-=back
-=head2 PIXEL OPERATORS
-The following operators modify the image pixels in various ways.
-=over 4
-=item clone $img
-Returns an exact copy of the image.
-=cut
-   sub clone($) {
-      $_[0]->clone
-   }
 =item clip $img
 =item clip $width, $height, $img
    sub rootalign($) {
       move -TX, -TY, $_[0]
    }
+=back
+=head2 COLOUR MODIFICATIONS
+The following operators change the pixels of the image.
+=over 4
 =item contrast $factor, $img
 =item contrast $r, $g, $b, $img
 =item contrast $r, $g, $b, $a, $img
 Adjusts the I<contrast> of an image.
-#TODO#
+The first form applies a single C<$factor> to red, green and blue, the
+second form applies separate factors to each colour channel, and the last
+form includes the alpha channel.
+Values from 0 to 1 lower the contrast, values higher than 1 increase the
+contrast.
+Due to limitations in the underlying XRender extension, lowering contrast
+also reduces brightness, while increasing contrast currently also
+increases brightness.
-=item brightness $factor, $img
+=item brightness $bias, $img
 =item brightness $r, $g, $b, $img
 =item brightness $r, $g, $b, $a, $img
 Adjusts the brightness of an image.
+The first form applies a single C<$bias> to red, green and blue, the
+second form applies separate biases to each colour channel, and the last
+form includes the alpha channel.
+Values less than 0 reduce brightness, while values larger than 0 increase
+it. Useful range is from -1 to 1 - the former results in a black, the
+latter in a white picture.
+Due to idiosynchrasies in the underlying XRender extension, biases less
+than zero can be I<very> slow.
 =cut
    sub contrast($$;$$;$) {
       my $img = pop;

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.44 by root, Sun Jun 10 11:31:22 2012 UTC vs. Revision 1.45 by root, Sun Jun 10 11:53:32 2012 UTC

Diff Legend

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.44 by root, Sun Jun 10 11:31:22 2012 UTC vs.
Revision 1.45 by root, Sun Jun 10 11:53:32 2012 UTC