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Revision 1.49 by root, Sun Jun 10 15:29:18 2012 UTC vs.
Revision 1.56 by root, Thu Jun 14 17:06:57 2012 UTC

1#! perl 1#! perl
2 2
3#:META:X_RESOURCE:%.expr:string:background expression 3#:META:X_RESOURCE:%.expr:string:background expression
4#:META:X_RESOURCE:%.border:boolean:respect the terminal border 4#:META:X_RESOURCE:%.border:boolean:respect the terminal border
5#:META:X_RESOURCE:%.interval:seconds:minimum time between updates 5#:META:X_RESOURCE:%.interval:seconds:minimum time between updates
6
7#TODO: once, rootalign
8 6
9=head1 NAME 7=head1 NAME
10 8
11 background - manage terminal background 9 background - manage terminal background
12 10
59 57
60For example, an expression such as C<scale load "$HOME/mybg.png"> scales the 58For example, an expression such as C<scale load "$HOME/mybg.png"> scales the
61image to the window size, so it relies on the window size and will 59image to the window size, so it relies on the window size and will
62be reevaluated each time it is changed, but not when it moves for 60be reevaluated each time it is changed, but not when it moves for
63example. That ensures that the picture always fills the terminal, even 61example. That ensures that the picture always fills the terminal, even
64after it's size changes. 62after its size changes.
65 63
66=head2 EXPRESSIONS 64=head2 EXPRESSIONS
67 65
68Expressions are normal Perl expressions, in fact, they are Perl blocks - 66Expressions are normal Perl expressions, in fact, they are Perl blocks -
69which means you could use multiple lines and statements: 67which means you could use multiple lines and statements:
73 return scale load "$HOME/weekday.png"; 71 return scale load "$HOME/weekday.png";
74 } else { 72 } else {
75 return scale load "$HOME/sunday.png"; 73 return scale load "$HOME/sunday.png";
76 } 74 }
77 75
78This expression gets evaluated once per hour. It will set F<sunday.png> as 76This expression is evaluated once per hour. It will set F<sunday.png> as
79background on Sundays, and F<weekday.png> on all other days. 77background on Sundays, and F<weekday.png> on all other days.
80 78
81Fortunately, we expect that most expressions will be much simpler, with 79Fortunately, we expect that most expressions will be much simpler, with
82little Perl knowledge needed. 80little Perl knowledge needed.
83 81
117horizontal and vertical dimensions. For example, this halves the image 115horizontal and vertical dimensions. For example, this halves the image
118width and doubles the image height: 116width and doubles the image height:
119 117
120 scale 0.5, 2, load "$HOME/mypic.png" 118 scale 0.5, 2, load "$HOME/mypic.png"
121 119
122Other effects than scalign are also readily available, for exmaple, you can 120Other effects than scaling are also readily available, for example, you can
123tile the image to fill the whole window, instead of resizing it: 121tile the image to fill the whole window, instead of resizing it:
124 122
125 tile load "$HOME/mypic.png" 123 tile load "$HOME/mypic.png"
126 124
127In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator 125In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator
153This only works for one cycle though, so as long as you load the same 151This only works for one cycle though, so as long as you load the same
154image every time, it will always be cached, but when you load a different 152image every time, it will always be cached, but when you load a different
155image, it will forget about the first one. 153image, it will forget about the first one.
156 154
157This allows you to either speed things up by keeping multiple images in 155This allows you to either speed things up by keeping multiple images in
158memory, or comserve memory by loading images more often. 156memory, or conserve memory by loading images more often.
159 157
160For example, you can keep two images in memory and use a random one like 158For example, you can keep two images in memory and use a random one like
161this: 159this:
162 160
163 my $img1 = load "img1.png"; 161 my $img1 = load "img1.png";
193Specifying this flag changes the behaviour, so that the image only 191Specifying this flag changes the behaviour, so that the image only
194replaces the background of the character area. 192replaces the background of the character area.
195 193
196=item --background-interval seconds 194=item --background-interval seconds
197 195
198Since some operations in the underlying XRender extension can effetively 196Since some operations in the underlying XRender extension can effectively
199freeze your X-server for prolonged time, this extension enforces a minimum 197freeze your X-server for prolonged time, this extension enforces a minimum
200time between updates, which is normally about 0.1 seconds. 198time between updates, which is normally about 0.1 seconds.
201 199
202If you want to do updates more often, you can decrease this safety 200If you want to do updates more often, you can decrease this safety
203interval with this switch. 201interval with this switch.
204 202
205=back 203=back
206 204
207=cut 205=cut
208 206
209our %_IMGCACHE; 207our %_IMG_CACHE;
210our $HOME; 208our $HOME;
211our ($self, $old, $new); 209our ($self, $old, $new);
212our ($x, $y, $w, $h); 210our ($x, $y, $w, $h);
213 211
214# enforce at least this interval between updates 212# enforce at least this interval between updates
230=item load $path 228=item load $path
231 229
232Loads the image at the given C<$path>. The image is set to plane tiling 230Loads the image at the given C<$path>. The image is set to plane tiling
233mode. 231mode.
234 232
235Loaded images will be cached for one cycle. 233Loaded images will be cached for one cycle, and shared between temrinals
234running in the same process (e.g. in C<urxvtd>).
236 235
236=item load_uc $path
237
238Load uncached - same as load, but does not cache the image. This function
239is most useufl if you want to optimise a background expression in some
240way.
241
237=cut 242=cut
243
244 sub load_uc($) {
245 my ($path) = @_;
246
247 $_IMG_CACHE{$path} || do {
248 my $img = $self->new_img_from_file ($path);
249 Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
250 $img
251 }
252 }
238 253
239 sub load($) { 254 sub load($) {
240 my ($path) = @_; 255 my ($path) = @_;
241 256
242 $new->{load}{$path} = $old->{load}{$path} || $self->new_img_from_file ($path); 257 $new->{load}{$path} = $old->{load}{$path} || load_uc $path;
243 } 258 }
244 259
245=item root 260=item root
246 261
247Returns the root window pixmap, that is, hopefully, the background image 262Returns the root window pixmap, that is, hopefully, the background image
251reevaluated when the bg image changes. 266reevaluated when the bg image changes.
252 267
253=cut 268=cut
254 269
255 sub root() { 270 sub root() {
256 $new->{rootpmap_sensitive} = 1; 271 $new->{again}{rootpmap} = 1;
257 die "root op not supported, exg, we need you"; 272 $self->new_img_from_root
258 } 273 }
259 274
260=item solid $colour 275=item solid $colour
261 276
262=item solid $width, $height, $colour 277=item solid $width, $height, $colour
286 301
287 sub clone($) { 302 sub clone($) {
288 $_[0]->clone 303 $_[0]->clone
289 } 304 }
290 305
291=back 306=item merge $img ...
307
308Takes any number of images and merges them together, creating a single image containing them all.
309
310=cut
311
312 sub merge(@) {
313 #TODO
314 }
292 315
293=head2 TILING MODES 316=head2 TILING MODES
294 317
295The following operators modify the tiling mode of an image, that is, the 318The following operators modify the tiling mode of an image, that is, the
296way that pixels outside the image area are painted when the image is used. 319way that pixels outside the image area are painted when the image is used.
326become transparent. This mode is most useful when you want to place an 349become transparent. This mode is most useful when you want to place an
327image over another image or the background colour while leaving all 350image over another image or the background colour while leaving all
328background pixels outside the image unchanged. 351background pixels outside the image unchanged.
329 352
330Example: load an image and display it in the upper left corner. The rest 353Example: load an image and display it in the upper left corner. The rest
331of the space is left "empty" (transparent or wahtever your compisotr does 354of the space is left "empty" (transparent or whatever your compositor does
332in alpha mode, else background colour). 355in alpha mode, else background colour).
333 356
334 pad load "mybg.png" 357 pad load "mybg.png"
335 358
336=item extend $img 359=item extend $img
337 360
338Extends the image over the whole plane, using the closest pixel in the 361Extends the image over the whole plane, using the closest pixel in the
339area outside the image. This mode is mostly useful when you more complex 362area outside the image. This mode is mostly useful when you use more complex
340filtering operations and want the pixels outside the image to have the 363filtering operations and want the pixels outside the image to have the
341same values as the pixels near the edge. 364same values as the pixels near the edge.
342 365
343Example: just for curiosity, how does this pixel extension stuff work? 366Example: just for curiosity, how does this pixel extension stuff work?
344 367
411the window size to conserve memory. 434the window size to conserve memory.
412 435
413Example: take the screen background, clip it to the window size, blur it a 436Example: take the screen background, clip it to the window size, blur it a
414bit, align it to the window position and use it as background. 437bit, align it to the window position and use it as background.
415 438
416 clip move -TX, -TY, blur 5, root 439 clip move -TX, -TY, once { blur 5, root }
417 440
418=cut 441=cut
419 442
420 sub TX() { $new->{position_sensitive} = 1; $x } 443 sub TX() { $new->{again}{position} = 1; $x }
421 sub TY() { $new->{position_sensitive} = 1; $y } 444 sub TY() { $new->{again}{position} = 1; $y }
422 sub TW() { $new->{size_sensitive} = 1; $w } 445 sub TW() { $new->{again}{size} = 1; $w }
423 sub TH() { $new->{size_sensitive} = 1; $h } 446 sub TH() { $new->{again}{size} = 1; $h }
424 447
425=item now 448=item now
426 449
427Returns the current time as (fractional) seconds since the epoch. 450Returns the current time as (fractional) seconds since the epoch.
428 451
435C<$seconds> seconds. 458C<$seconds> seconds.
436 459
437Example: load some image and rotate it according to the time of day (as if it were 460Example: load some image and rotate it according to the time of day (as if it were
438the hour pointer of a clock). Update this image every minute. 461the hour pointer of a clock). Update this image every minute.
439 462
440 again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png" 463 again 60; rotate 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
441 464
442=item counter $seconds 465=item counter $seconds
443 466
444Like C<again>, but also returns an increasing counter value, starting at 467Like C<again>, but also returns an increasing counter value, starting at
4450, which might be useful for some simple animation effects. 4680, which might be useful for some simple animation effects.
447=cut 470=cut
448 471
449 sub now() { urxvt::NOW } 472 sub now() { urxvt::NOW }
450 473
451 sub again($) { 474 sub again($) {
452 $new->{again} = $_[0]; 475 $new->{again}{time} = $_[0];
453 } 476 }
454 477
455 sub counter($) { 478 sub counter($) {
456 $new->{again} = $_[0]; 479 $new->{again}{time} = $_[0];
457 $self->{counter} + 0 480 $self->{counter} + 0
458 } 481 }
459 482
460=back 483=back
461 484
632 655
633 sub rootalign($) { 656 sub rootalign($) {
634 move -TX, -TY, $_[0] 657 move -TX, -TY, $_[0]
635 } 658 }
636 659
660=item rotate $center_x, $center_y, $degrees
661
662Rotates the image by C<$degrees> degrees, counter-clockwise, around the
663pointer at C<$center_x> and C<$center_y> (specified as factor of image
664width/height).
665
666#TODO# new width, height, maybe more operators?
667
668Example: rotate the image by 90 degrees
669
670=cut
671
672 sub rotate($$$$) {
673 my $img = pop;
674 $img->rotate (
675 $_[0] * $img->w,
676 $_[1] * $img->h,
677 $_[2] * (3.14159265 / 180),
678 )
679 }
680
637=back 681=back
638 682
639=head2 COLOUR MODIFICATIONS 683=head2 COLOUR MODIFICATIONS
640 684
641The following operators change the pixels of the image. 685The following operators change the pixels of the image.
675 719
676Values less than 0 reduce brightness, while values larger than 0 increase 720Values less than 0 reduce brightness, while values larger than 0 increase
677it. Useful range is from -1 to 1 - the former results in a black, the 721it. Useful range is from -1 to 1 - the former results in a black, the
678latter in a white picture. 722latter in a white picture.
679 723
680Due to idiosynchrasies in the underlying XRender extension, biases less 724Due to idiosyncrasies in the underlying XRender extension, biases less
681than zero can be I<very> slow. 725than zero can be I<very> slow.
682 726
683=cut 727=cut
684 728
685 sub contrast($$;$$;$) { 729 sub contrast($$;$$;$) {
723 sub blur($$;$) { 767 sub blur($$;$) {
724 my $img = pop; 768 my $img = pop;
725 $img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0]) 769 $img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
726 } 770 }
727 771
728=item rotate $new_width, $new_height, $center_x, $center_y, $degrees 772=back
729 773
730Rotates the image by C<$degrees> degrees, counter-clockwise, around the 774=head2 OTHER STUFF
731pointer at C<$center_x> and C<$center_y> (specified as factor of image
732width/height), generating a new image with width C<$new_width> and height
733C<$new_height>.
734 775
735#TODO# new width, height, maybe more operators? 776Anything that didn't fit any of the other categories, even after applying
777force and closing our eyes.
736 778
737Example: rotate the image by 90 degrees 779=over 4
738 780
739=cut 781=item once { ... }
740 782
741 sub rotate($$$$$$) { 783This function takes a code block as argument, that is, one or more
742 my $img = pop; 784statements enclosed by braces.
743 $img->rotate ( 785
744 $_[0], 786The trick is that this code block is only evaluated once - future calls
745 $_[1], 787will simply return the original image (yes, it should only be used with
746 $_[2] * $img->w, 788images).
747 $_[3] * $img->h, 789
748 $_[4] * (3.14159265 / 180), 790This can be extremely useful to avoid redoign the same slow operations
791again and again- for example, if your background expression takes the root
792background, blurs it and then root-aligns it it would have to blur the
793root background on every window move or resize.
794
795Putting the blur into a C<once> block will make sure the blur is only done
796once:
797
798 rootlign once { blur 10, root }
799
800This leaves the question of how to force reevaluation of the block, in
801case the root background changes: Right now, all once blocks forget that
802they ahve been executed before each time the root background changes (if
803the expression is sensitive to that) or when C<once_again> is called.
804
805=item once_again
806
807Resets all C<once> block as if they had never been called, i.e. on the
808next call they will be reevaluated again.
809
810=cut
811
812 sub once(&) {
813 my $once = $self->{once_cache}{$_[0]+0} ||= do {
814 local $new->{again};
815 my @res = $_[0]();
816 [$new->{again}, \@res]
749 ) 817 };
818
819 $new->{again} = {
820 %{ $new->{again} },
821 %{ $once->[0] }
822 };
823
824 # in scalar context we always return the first original result, which
825 # is not quite how perl works.
826 wantarray
827 ? @{ $once->[1] }
828 : $once->[1][0]
829 }
830
831 sub once_again() {
832 delete $self->{once_cache};
750 } 833 }
751 834
752=back 835=back
753 836
754=cut 837=cut
799 882
800 my $img = eval { $self->{expr}->() }; 883 my $img = eval { $self->{expr}->() };
801 warn $@ if $@;#d# 884 warn $@ if $@;#d#
802 die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img"; 885 die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";
803 886
804 $state->{size_sensitive} = 1 887 # if the expression is sensitive to external events, prepare reevaluation then
888
889 my $again = delete $state->{again};
890
891 $again->{size} = 1
805 if $img->repeat_mode != urxvt::RepeatNormal; 892 if $img->repeat_mode != urxvt::RepeatNormal;
806 893
807 # if the expression is sensitive to external events, prepare reevaluation then
808
809 my $repeat;
810
811 if (my $again = $state->{again}) { 894 if (my $again = $again->{time}) {
812 $repeat = 1;
813 my $self = $self; 895 my $self = $self;
814 $state->{timer} = $again == $old->{again} 896 $state->{timer} = $again == $old->{again}
815 ? $old->{timer} 897 ? $old->{timer}
816 : urxvt::timer->new->after ($again)->interval ($again)->cb (sub { 898 : urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
817 ++$self->{counter}; 899 ++$self->{counter};
818 $self->recalculate 900 $self->recalculate
819 }); 901 });
820 } 902 }
821 903
822 if (delete $state->{position_sensitive}) { 904 if ($again->{position}) {
823 $repeat = 1;
824 $self->enable (position_change => sub { $_[0]->recalculate }); 905 $self->enable (position_change => sub { $_[0]->recalculate });
825 } else { 906 } else {
826 $self->disable ("position_change"); 907 $self->disable ("position_change");
827 } 908 }
828 909
829 if (delete $state->{size_sensitive}) { 910 if ($again->{size}) {
830 $repeat = 1;
831 $self->enable (size_change => sub { $_[0]->recalculate }); 911 $self->enable (size_change => sub { $_[0]->recalculate });
832 } else { 912 } else {
833 $self->disable ("size_change"); 913 $self->disable ("size_change");
834 } 914 }
835 915
836 if (delete $state->{rootpmap_sensitive}) { 916 if ($again->{rootpmap}) {
837 $repeat = 1;
838 $self->enable (rootpmap_change => sub { $_[0]->recalculate }); 917 $self->enable (rootpmap_change => sub {
918 delete $_[0]{once_cache}; # this will override once-block values from
919 $_[0]->recalculate;
920 });
839 } else { 921 } else {
840 $self->disable ("rootpmap_change"); 922 $self->disable ("rootpmap_change");
841 } 923 }
842 924
843 # clear stuff we no longer need 925 # clear stuff we no longer need
844 926
845 %$old = (); 927 %$old = ();
846 928
847 unless ($repeat) { 929 unless (%$again) {
848 delete $self->{state}; 930 delete $self->{state};
849 delete $self->{expr}; 931 delete $self->{expr};
850 } 932 }
851 933
852 # set background pixmap 934 # set background pixmap

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