--- rxvt-unicode/src/perl/background	2012/06/05 12:08:23	1.3
+++ rxvt-unicode/src/perl/background	2012/06/05 22:23:07	1.14
@@ -1,6 +1,14 @@
 #! perl
 
-our $EXPR = 'move load "/root/pix/das_fette_schwein.jpg", left, top';
+#:META:RESOURCE:$$:string:background expression
+#:META:RESOURCE:$$-enable:boolean:some boolean
+
+our $EXPR = 'move load "/root/pix/das_fette_schwein.jpg", repeat_wrap, X, Y';
+$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"
+';
 #$EXPR = 'blur root, 10, 10'
 #$EXPR = 'blur move (root, -x, -y), 5, 5'
 #resize load "/root/pix/das_fette_schwein.jpg", w, h
@@ -10,6 +18,9 @@
 our ($bgdsl_self, $old, $new);
 our ($l, $t, $w, $h);
 
+# enforce at leats this time between updates
+our $MIN_INTERVAL = 1/100;
+
 {
    package urxvt::bgdsl; # background language
 
@@ -25,56 +36,80 @@
    }
 
    sub root() {
+      $new->{rootpmap_sensitive} = 1;
       die "root op not supported, exg, we need you";
    }
 
+#   sub clone($) {
+#      $_[0]->clone
+#   }
+
+   sub clip($$$$$;$) {
+      my $img = pop;
+      $img->sub_rect ($_[0], $_[1], $_[2], $_[3], $_[4])
+   }
+
    sub resize($$$) {
-      $_[0]->scale ($_[1], $_[2])
+      my $img = pop;
+      $img->scale ($_[0], $_[1])
    }
 
-   sub move($$$) {
-      # TODO: must be simpler
-      $_[0]->transform ($_[0]->w, $_[0]->h, $_[1],
-         1, 0, -$_[2],
-         0, 1, -$_[3],
-         0, 0,      1,
+   # TODO: ugly
+   sub move($$;$) {
+      my $img = pop;
+      $img->sub_rect (
+         $_[0], $_[1],
+         $img->w, $img->h,
+         $_[2],
       )
    }
 
-   sub rotate($$$$) {
-      $_[0]->rotate ($_[0], $_[1], $_[2], $_[3] * (3.14159265 / 180))
+   sub rotate($$$$$$;$) {
+      my $img = pop;
+      $img->rotate (
+         $_[0],
+         $_[1],
+         $_[2] * $img->w * .01,
+         $_[3] * $img->h * .01,
+         $_[4] * (3.14159265 / 180),
+         $_[5],
+      )
    }
 
    sub blur($$$) {
-      my ($img, $rh, $rv) = @_;
+      my ($rh, $rv, $img) = @_;
 
-      $img = $img->clone;
-      $img->clone->blur ($rh, $rv);
-      $img
+      $img->blur ($rh, $rv);
    }
 
    sub contrast($$;$$;$) {
-      my ($img, $r, $g, $b, $a) = @_;
+      my $img = pop;
+      my ($r, $g, $b, $a) = @_;
+
       ($g, $b) = ($r, $r) if @_ < 4;
       $a       = 1        if @_ < 5;
+
       $img = $img->clone;
       $img->contrast ($r, $g, $b, $a);
       $img
    }
 
    sub brightness($$;$$;$) {
-      my ($img, $r, $g, $b, $a) = @_;
+      my $img = pop;
+      my ($r, $g, $b, $a) = @_;
+
       ($g, $b) = ($r, $r) if @_ < 4;
       $a       = 1        if @_ < 5;
+
       $img = $img->clone;
       $img->brightness ($r, $g, $b, $a);
       $img
    }
 
-   sub left  () { $new->{position_sensitive} = 1; $l }
-   sub top   () { $new->{position_sensitive} = 1; $t }
-   sub width () { $new->{size_sensitive}     = 1; $w }
-   sub height() { $new->{size_sensitive}     = 1; $h }
+   sub X() { $new->{position_sensitive} = 1; $l }
+   sub Y() { $new->{position_sensitive} = 1; $t }
+   sub W() { $new->{size_sensitive}     = 1; $w }
+   sub H() { $new->{size_sensitive}     = 1; $h }
 
    sub now() { urxvt::NOW }
 
@@ -84,7 +119,7 @@
 
    sub counter($) {
       $new->{again} = $_[0];
-      $bgdsl_self->{counter}++ + 0
+      $bgdsl_self->{counter} + 0
    }
 }
 
@@ -98,7 +133,6 @@
 sub set_expr {
    my ($self, $expr) = @_;
 
-   local $Data::Dumper::Deparse=1; use Data::Dumper; warn Dumper $expr;#d#
    $self->{expr} = $expr;
    $self->recalculate;
 }
@@ -107,6 +141,19 @@
 sub recalculate {
    my ($self) = @_;
 
+   # rate limit evaluation
+
+   if ($self->{next_refresh} > urxvt::NOW) {
+      $self->{next_refresh_timer} = urxvt::timer->new->after ($self->{next_refresh} - urxvt::NOW)->cb (sub {
+         $self->recalculate;
+      });
+      return;
+   }
+
+   $self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
+
+   # set environment to evaluate user expression
+
    local $bgdsl_self = $self;
 
    local $old = $self->{state};
@@ -115,16 +162,23 @@
    ($l, $t, $w, $h) =
       $self->get_geometry;
 
-      warn "$l, $t";#d#
+   # evaluate user expression
 
    my $img = eval { $self->{expr}->() };
    warn $@ if $@;#d#
 
+   # if the expression is sensitive to external events, prepare reevaluation then
+
    my $repeat;
 
    if (my $again = $state->{again}) {
       $repeat = 1;
-      $state->{again} = urxvt::timer->new->after ($again)->cb (sub { $self->recalculate });
+      $state->{timer} = $again == $old->{again}
+                        ? $old->{timer}
+                        : urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
+                             ++$self->{counter};
+                             $self->recalculate
+                          });
    }
 
    if (delete $state->{position_sensitive}) {
@@ -141,9 +195,27 @@
       $self->disable ("size_change");
    }
 
-   # TODO: install handlers for geometry changes &c
+   if (delete $state->{rootpmap_sensitive}) {
+      $repeat = 1;
+      $self->enable (rootpmap_change => sub { $_[0]->recalculate });
+   } else {
+      $self->disable ("rootpmap_change");
+   }
+
+   # clear stuff we no longer need
+
+   %$old = ();
+
+   unless ($repeat) {
+      delete $self->{state};
+      delete $self->{expr};
+   }
+
+   # prepare and set background pixmap
+
+   $img = $img->sub_rect (0, 0, $w, $h)
+      if $img->w != $w || $img->h != $h;
 
-   warn $img;
    $self->set_background ($img);
    $self->scr_recolour (0);
    $self->want_refresh;