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Revision 1.49 by root, Sun Jun 10 15:29:18 2012 UTC vs.
Revision 1.57 by root, Thu Jun 14 18:06:15 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
309image containing them all.
310
311=cut
312
313 sub merge(@) {
314 #TODO
315 }
292 316
293=head2 TILING MODES 317=head2 TILING MODES
294 318
295The following operators modify the tiling mode of an image, that is, the 319The 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. 320way 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 350become transparent. This mode is most useful when you want to place an
327image over another image or the background colour while leaving all 351image over another image or the background colour while leaving all
328background pixels outside the image unchanged. 352background pixels outside the image unchanged.
329 353
330Example: load an image and display it in the upper left corner. The rest 354Example: 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 355of the space is left "empty" (transparent or whatever your compositor does
332in alpha mode, else background colour). 356in alpha mode, else background colour).
333 357
334 pad load "mybg.png" 358 pad load "mybg.png"
335 359
336=item extend $img 360=item extend $img
337 361
338Extends the image over the whole plane, using the closest pixel in the 362Extends 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 363area 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 364filtering operations and want the pixels outside the image to have the
341same values as the pixels near the edge. 365same values as the pixels near the edge.
342 366
343Example: just for curiosity, how does this pixel extension stuff work? 367Example: just for curiosity, how does this pixel extension stuff work?
344 368
411the window size to conserve memory. 435the window size to conserve memory.
412 436
413Example: take the screen background, clip it to the window size, blur it a 437Example: 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. 438bit, align it to the window position and use it as background.
415 439
416 clip move -TX, -TY, blur 5, root 440 clip move -TX, -TY, once { blur 5, root }
417 441
418=cut 442=cut
419 443
420 sub TX() { $new->{position_sensitive} = 1; $x } 444 sub TX() { $new->{again}{position} = 1; $x }
421 sub TY() { $new->{position_sensitive} = 1; $y } 445 sub TY() { $new->{again}{position} = 1; $y }
422 sub TW() { $new->{size_sensitive} = 1; $w } 446 sub TW() { $new->{again}{size} = 1; $w }
423 sub TH() { $new->{size_sensitive} = 1; $h } 447 sub TH() { $new->{again}{size} = 1; $h }
424 448
425=item now 449=item now
426 450
427Returns the current time as (fractional) seconds since the epoch. 451Returns the current time as (fractional) seconds since the epoch.
428 452
435C<$seconds> seconds. 459C<$seconds> seconds.
436 460
437Example: load some image and rotate it according to the time of day (as if it were 461Example: 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. 462the hour pointer of a clock). Update this image every minute.
439 463
440 again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png" 464 again 60; rotate 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
441 465
442=item counter $seconds 466=item counter $seconds
443 467
444Like C<again>, but also returns an increasing counter value, starting at 468Like C<again>, but also returns an increasing counter value, starting at
4450, which might be useful for some simple animation effects. 4690, which might be useful for some simple animation effects.
447=cut 471=cut
448 472
449 sub now() { urxvt::NOW } 473 sub now() { urxvt::NOW }
450 474
451 sub again($) { 475 sub again($) {
452 $new->{again} = $_[0]; 476 $new->{again}{time} = $_[0];
453 } 477 }
454 478
455 sub counter($) { 479 sub counter($) {
456 $new->{again} = $_[0]; 480 $new->{again}{time} = $_[0];
457 $self->{counter} + 0 481 $self->{counter} + 0
458 } 482 }
459 483
460=back 484=back
461 485
632 656
633 sub rootalign($) { 657 sub rootalign($) {
634 move -TX, -TY, $_[0] 658 move -TX, -TY, $_[0]
635 } 659 }
636 660
661=item rotate $center_x, $center_y, $degrees
662
663Rotates the image by C<$degrees> degrees, counter-clockwise, around the
664pointer at C<$center_x> and C<$center_y> (specified as factor of image
665width/height).
666
667#TODO# new width, height, maybe more operators?
668
669Example: rotate the image by 90 degrees
670
671=cut
672
673 sub rotate($$$$) {
674 my $img = pop;
675 $img->rotate (
676 $_[0] * $img->w,
677 $_[1] * $img->h,
678 $_[2] * (3.14159265 / 180),
679 )
680 }
681
637=back 682=back
638 683
639=head2 COLOUR MODIFICATIONS 684=head2 COLOUR MODIFICATIONS
640 685
641The following operators change the pixels of the image. 686The following operators change the pixels of the image.
675 720
676Values less than 0 reduce brightness, while values larger than 0 increase 721Values less than 0 reduce brightness, while values larger than 0 increase
677it. Useful range is from -1 to 1 - the former results in a black, the 722it. Useful range is from -1 to 1 - the former results in a black, the
678latter in a white picture. 723latter in a white picture.
679 724
680Due to idiosynchrasies in the underlying XRender extension, biases less 725Due to idiosyncrasies in the underlying XRender extension, biases less
681than zero can be I<very> slow. 726than zero can be I<very> slow.
682 727
683=cut 728=cut
684 729
685 sub contrast($$;$$;$) { 730 sub contrast($$;$$;$) {
723 sub blur($$;$) { 768 sub blur($$;$) {
724 my $img = pop; 769 my $img = pop;
725 $img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0]) 770 $img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
726 } 771 }
727 772
728=item rotate $new_width, $new_height, $center_x, $center_y, $degrees 773=back
729 774
730Rotates the image by C<$degrees> degrees, counter-clockwise, around the 775=head2 OTHER STUFF
731pointer at C<$center_x> and C<$center_y> (specified as factor of image
732width/height), generating a new image with width C<$new_width> and height
733C<$new_height>.
734 776
735#TODO# new width, height, maybe more operators? 777Anything that didn't fit any of the other categories, even after applying
778force and closing our eyes.
736 779
737Example: rotate the image by 90 degrees 780=over 4
738 781
739=cut 782=item once { ... }
740 783
741 sub rotate($$$$$$) { 784This function takes a code block as argument, that is, one or more
742 my $img = pop; 785statements enclosed by braces.
743 $img->rotate ( 786
744 $_[0], 787The trick is that this code block is only evaluated once - future calls
745 $_[1], 788will simply return the original image (yes, it should only be used with
746 $_[2] * $img->w, 789images).
747 $_[3] * $img->h, 790
748 $_[4] * (3.14159265 / 180), 791This can be extremely useful to avoid redoign the same slow operations
792again and again- for example, if your background expression takes the root
793background, blurs it and then root-aligns it it would have to blur the
794root background on every window move or resize.
795
796Putting the blur into a C<once> block will make sure the blur is only done
797once:
798
799 rootlign once { blur 10, root }
800
801This leaves the question of how to force reevaluation of the block, in
802case the root background changes: Right now, all once blocks forget that
803they ahve been executed before each time the root background changes (if
804the expression is sensitive to that) or when C<once_again> is called.
805
806=item once_again
807
808Resets all C<once> block as if they had never been called, i.e. on the
809next call they will be reevaluated again.
810
811=cut
812
813 sub once(&) {
814 my $once = $self->{once_cache}{$_[0]+0} ||= do {
815 local $new->{again};
816 my @res = $_[0]();
817 [$new->{again}, \@res]
749 ) 818 };
819
820 $new->{again} = {
821 %{ $new->{again} },
822 %{ $once->[0] }
823 };
824
825 # in scalar context we always return the first original result, which
826 # is not quite how perl works.
827 wantarray
828 ? @{ $once->[1] }
829 : $once->[1][0]
830 }
831
832 sub once_again() {
833 delete $self->{once_cache};
750 } 834 }
751 835
752=back 836=back
753 837
754=cut 838=cut
799 883
800 my $img = eval { $self->{expr}->() }; 884 my $img = eval { $self->{expr}->() };
801 warn $@ if $@;#d# 885 warn $@ if $@;#d#
802 die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img"; 886 die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";
803 887
804 $state->{size_sensitive} = 1 888 # if the expression is sensitive to external events, prepare reevaluation then
889
890 my $again = delete $state->{again};
891
892 $again->{size} = 1
805 if $img->repeat_mode != urxvt::RepeatNormal; 893 if $img->repeat_mode != urxvt::RepeatNormal;
806 894
807 # if the expression is sensitive to external events, prepare reevaluation then
808
809 my $repeat;
810
811 if (my $again = $state->{again}) { 895 if (my $again = $again->{time}) {
812 $repeat = 1;
813 my $self = $self; 896 my $self = $self;
814 $state->{timer} = $again == $old->{again} 897 $state->{timer} = $again == $old->{again}
815 ? $old->{timer} 898 ? $old->{timer}
816 : urxvt::timer->new->after ($again)->interval ($again)->cb (sub { 899 : urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
817 ++$self->{counter}; 900 ++$self->{counter};
818 $self->recalculate 901 $self->recalculate
819 }); 902 });
820 } 903 }
821 904
822 if (delete $state->{position_sensitive}) { 905 if ($again->{position}) {
823 $repeat = 1;
824 $self->enable (position_change => sub { $_[0]->recalculate }); 906 $self->enable (position_change => sub { $_[0]->recalculate });
825 } else { 907 } else {
826 $self->disable ("position_change"); 908 $self->disable ("position_change");
827 } 909 }
828 910
829 if (delete $state->{size_sensitive}) { 911 if ($again->{size}) {
830 $repeat = 1;
831 $self->enable (size_change => sub { $_[0]->recalculate }); 912 $self->enable (size_change => sub { $_[0]->recalculate });
832 } else { 913 } else {
833 $self->disable ("size_change"); 914 $self->disable ("size_change");
834 } 915 }
835 916
836 if (delete $state->{rootpmap_sensitive}) { 917 if ($again->{rootpmap}) {
837 $repeat = 1;
838 $self->enable (rootpmap_change => sub { $_[0]->recalculate }); 918 $self->enable (rootpmap_change => sub {
919 delete $_[0]{once_cache}; # this will override once-block values from
920 $_[0]->recalculate;
921 });
839 } else { 922 } else {
840 $self->disable ("rootpmap_change"); 923 $self->disable ("rootpmap_change");
841 } 924 }
842 925
843 # clear stuff we no longer need 926 # clear stuff we no longer need
844 927
845 %$old = (); 928 %$old = ();
846 929
847 unless ($repeat) { 930 unless (%$again) {
848 delete $self->{state}; 931 delete $self->{state};
849 delete $self->{expr}; 932 delete $self->{expr};
850 } 933 }
851 934
852 # set background pixmap 935 # set background pixmap

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