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Revision 1.62 by root, Sun Jun 17 21:58:18 2012 UTC vs.
Revision 1.67 by sf-exg, Fri Jun 29 18:12:25 2012 UTC

26to be as simple as possible. 26to be as simple as possible.
27 27
28For example, to load an image and scale it to the window size, you would 28For example, to load an image and scale it to the window size, you would
29use: 29use:
30 30
31 urxvt --background-expr 'scale load "/path/to/mybg.png"' 31 urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
32 32
33Or specified as a X resource: 33Or specified as a X resource:
34 34
35 URxvt.background-expr: scale load "/path/to/mybg.png" 35 URxvt.background-expr: scale keep { load "/path/to/mybg.png" }
36 36
37=head1 THEORY OF OPERATION 37=head1 THEORY OF OPERATION
38 38
39At startup, just before the window is mapped for the first time, the 39At startup, just before the window is mapped for the first time, the
40expression is evaluated and must yield an image. The image is then 40expression is evaluated and must yield an image. The image is then
53If any of the parameters that the expression relies on changes (when the 53If any of the parameters that the expression relies on changes (when the
54window is moved or resized, its position or size changes; when the root 54window is moved or resized, its position or size changes; when the root
55pixmap is replaced by another one the root background changes; or when the 55pixmap is replaced by another one the root background changes; or when the
56timer elapses), then the expression will be evaluated again. 56timer elapses), then the expression will be evaluated again.
57 57
58For example, an expression such as C<scale load "$HOME/mybg.png"> scales the 58For example, an expression such as C<scale keep { load "$HOME/mybg.png"
59image to the window size, so it relies on the window size and will 59}> scales the image to the window size, so it relies on the window size
60be reevaluated each time it is changed, but not when it moves for 60and will be reevaluated each time it is changed, but not when it moves for
61example. That ensures that the picture always fills the terminal, even 61example. That ensures that the picture always fills the terminal, even
62after its size changes. 62after its size changes.
63 63
64=head2 EXPRESSIONS 64=head2 EXPRESSIONS
65 65
66Expressions are normal Perl expressions, in fact, they are Perl blocks - 66Expressions are normal Perl expressions, in fact, they are Perl blocks -
67which means you could use multiple lines and statements: 67which means you could use multiple lines and statements:
68 68
69 scale keep {
69 again 3600; 70 again 3600;
70 if (localtime now)[6]) { 71 if (localtime now)[6]) {
71 return scale load "$HOME/weekday.png"; 72 return load "$HOME/weekday.png";
72 } else { 73 } else {
73 return scale load "$HOME/sunday.png"; 74 return load "$HOME/sunday.png";
75 }
74 } 76 }
75 77
76This expression is evaluated once per hour. It will set F<sunday.png> as 78This expression is evaluated once per hour. It will set F<sunday.png> as
77background on Sundays, and F<weekday.png> on all other days. 79background on Sundays, and F<weekday.png> on all other days.
78 80
115horizontal and vertical dimensions. For example, this halves the image 117horizontal and vertical dimensions. For example, this halves the image
116width and doubles the image height: 118width and doubles the image height:
117 119
118 scale 0.5, 2, load "$HOME/mypic.png" 120 scale 0.5, 2, load "$HOME/mypic.png"
119 121
120Other effects than scaling are also readily available, for example, you can 122IF you try out these expressions, you might suffer from sluggishness,
121tile the image to fill the whole window, instead of resizing it: 123because each time the terminal is resized, it again loads the PNG image
124and scales it. Scaling is usually fast, but loading the image can be quite
125time consuming. This is where C<keep> comes in handy:
122 126
127 scale 0.5, 2, keep { load "$HOME/mypic.png" }
128
129The C<keep> operator executes all the statements inside the braces only
130once, or when it thinks the outcome might change. In other cases it
131returns the last value computed by the brace block.
132
133This means that the C<load> is only executed once, which makes it much
134faster, but also means that more memory is being used, because the loaded
135image must be kept in memory at all times. In this expression, the
136trade-off is likely worth it.
137
138But back to effects: Other effects than scaling are also readily
139available, for example, you can tile the image to fill the whole window,
140instead of resizing it:
141
123 tile load "$HOME/mypic.png" 142 tile keep { load "$HOME/mypic.png" }
124 143
125In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator 144In fact, images returned by C<load> are in C<tile> mode by default, so the
126is kind of superfluous. 145C<tile> operator is kind of superfluous.
127 146
128Another common effect is to mirror the image, so that the same edges touch: 147Another common effect is to mirror the image, so that the same edges
148touch:
129 149
130 mirror load "$HOME/mypic.png" 150 mirror keep { load "$HOME/mypic.png" }
131 151
132This is also a typical background expression: 152Another common background expression is:
133 153
134 rootalign root 154 rootalign root
135 155
136It first takes a snapshot of the screen background image, and then 156This one first takes a snapshot of the screen background image, and then
137moves it to the upper left corner of the screen - the result is 157moves it to the upper left corner of the screen (as opposed to the upper
138pseudo-transparency, as the image seems to be static while the window is 158left corner of the terminal window)- the result is pseudo-transparency:
139moved around. 159the image seems to be static while the window is moved around.
140 160
141=head2 CYCLES AND CACHING 161=head2 CACHING AND SENSITIVITY
142 162
143As has been mentioned before, the expression might be evaluated multiple 163Since some operations (such as C<load> and C<blur>) can take a long time,
144times. Each time the expression is reevaluated, a new cycle is said to 164caching results can be very important for a smooth operation. Caching can
145have begun. Many operators cache their results till the next cycle. 165also be useful to reduce memory usage, though, for example, when an image
166is cached by C<load>, it could be shared by multiple terminal windows
167running inside urxvtd.
146 168
147For example, the C<load> operator keeps a copy of the image. If it is 169=head3 C<keep { ... }> caching
148asked to load the same image on the next cycle it will not load it again,
149but return the cached copy.
150 170
151This only works for one cycle though, so as long as you load the same 171The most important way to cache expensive operations is to use C<keep {
152image every time, it will always be cached, but when you load a different 172... }>. The C<keep> operator takes a block of multiple statements enclosed
153image, it will forget about the first one. 173by C<{}> and keeps the return value in memory.
154 174
155This allows you to either speed things up by keeping multiple images in 175An expression can be "sensitive" to various external events, such as
156memory, or conserve memory by loading images more often. 176scaling or moving the window, root background changes and timers. Simply
177using an expression (such as C<scale> without parameters) that depends on
178certain changing values (called "variables"), or using those variables
179directly, will make an expression sensitive to these events - for example,
180using C<scale> or C<TW> will make the expression sensitive to the terminal
181size, and thus to resizing events.
157 182
158For example, you can keep two images in memory and use a random one like 183When such an event happens, C<keep> will automatically trigger a
159this: 184reevaluation of the whole expression with the new value of the expression.
160 185
161 my $img1 = load "img1.png"; 186C<keep> is most useful for expensive operations, such as C<blur>:
162 my $img2 = load "img2.png";
163 (0.5 > rand) ? $img1 : $img2
164 187
165Since both images are "loaded" every time the expression is evaluated, 188 rootalign once { blur 20, root }
166they are always kept in memory. Contrast this version:
167 189
168 my $path1 = "img1.png"; 190This makes a blurred copy of the root background once, and on subsequent
169 my $path2 = "img2.png"; 191calls, just root-aligns it. Since C<blur> is usually quite slow and
170 load ((0.5 > rand) ? $path1 : $path2) 192C<rootalign> is quite fast, this trades extra memory (for the cached
193blurred pixmap) with speed (blur only needs to be redone when root
194changes).
171 195
172Here, a path is selected randomly, and load is only called for one image, 196=head3 C<load> caching
173so keeps only one image in memory. If, on the next evaluation, luck 197
174decides to use the other path, then it will have to load that image again. 198The C<load> operator itself does not keep images in memory, but as long as
199the image is still in memory, C<load> will use the in-memory image instead
200of loading it freshly from disk.
201
202That means that this expression:
203
204 keep { load "$HOME/path..." }
205
206Not only caches the image in memory, other terminal instances that try to
207C<load> it can reuse that in-memory copy.
175 208
176=head1 REFERENCE 209=head1 REFERENCE
177 210
178=head2 COMMAND LINE SWITCHES 211=head2 COMMAND LINE SWITCHES
179 212
204 237
205=cut 238=cut
206 239
207our %_IMG_CACHE; 240our %_IMG_CACHE;
208our $HOME; 241our $HOME;
209our ($self, $old, $new); 242our ($self, $frame);
210our ($x, $y, $w, $h); 243our ($x, $y, $w, $h);
211 244
212# enforce at least this interval between updates 245# enforce at least this interval between updates
213our $MIN_INTERVAL = 6/59.951; 246our $MIN_INTERVAL = 6/59.951;
214 247
215{ 248{
216 package urxvt::bgdsl; # background language 249 package urxvt::bgdsl; # background language
250
251 sub FR_PARENT() { 0 } # parent frame, if any - must be #0
252 sub FR_CACHE () { 1 } # cached values
253 sub FR_AGAIN () { 2 } # what this expr is sensitive to
254 sub FR_STATE () { 3 } # watchers etc.
217 255
218 use List::Util qw(min max sum shuffle); 256 use List::Util qw(min max sum shuffle);
219 257
220=head2 PROVIDERS/GENERATORS 258=head2 PROVIDERS/GENERATORS
221 259
228=item load $path 266=item load $path
229 267
230Loads the image at the given C<$path>. The image is set to plane tiling 268Loads the image at the given C<$path>. The image is set to plane tiling
231mode. 269mode.
232 270
233Loaded images will be cached for one cycle, and shared between temrinals 271If the image is already in memory (e.g. because another terminal instance
234running in the same process (e.g. in C<urxvtd>). 272uses it), then the in-memory copy us returned instead.
235 273
236=item load_uc $path 274=item load_uc $path
237 275
238Load uncached - same as load, but does not cache the image. This function 276Load uncached - same as load, but does not cache the image, which means it
239is most useufl if you want to optimise a background expression in some 277is I<always> loaded from the filesystem again.
240way.
241 278
242=cut 279=cut
243 280
244 sub load_uc($) { 281 sub load_uc($) {
282 $self->new_img_from_file ($path)
283 }
284
285 sub load($) {
245 my ($path) = @_; 286 my ($path) = @_;
246 287
247 $_IMG_CACHE{$path} || do { 288 $_IMG_CACHE{$path} || do {
248 my $img = $self->new_img_from_file ($path); 289 my $img = load_uc $path;
249 Scalar::Util::weaken ($_IMG_CACHE{$path} = $img); 290 Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
250 $img 291 $img
251 } 292 }
252 } 293 }
253 294
254 sub load($) {
255 my ($path) = @_;
256
257 $new->{load}{$path} = $old->{load}{$path} || load_uc $path;
258 }
259
260=item root 295=item root
261 296
262Returns the root window pixmap, that is, hopefully, the background image 297Returns the root window pixmap, that is, hopefully, the background image
263of your screen. 298of your screen.
264 299
266reevaluated when the bg image changes. 301reevaluated when the bg image changes.
267 302
268=cut 303=cut
269 304
270 sub root() { 305 sub root() {
271 $new->{again}{rootpmap} = 1; 306 $frame->[FR_AGAIN]{rootpmap} = 1;
272 $self->new_img_from_root 307 $self->new_img_from_root
273 } 308 }
274 309
275=item solid $colour 310=item solid $colour
276 311
305 340
306=item merge $img ... 341=item merge $img ...
307 342
308Takes any number of images and merges them together, creating a single 343Takes any number of images and merges them together, creating a single
309image containing them all. The tiling mode of the first image is used as 344image containing them all. The tiling mode of the first image is used as
310the tiling mdoe of the resulting image. 345the tiling mode of the resulting image.
311 346
312This function is called automatically when an expression returns multiple 347This function is called automatically when an expression returns multiple
313images. 348images.
314 349
315=cut 350=cut
450Using these functions make your expression sensitive to window moves. 485Using these functions make your expression sensitive to window moves.
451 486
452These functions are mainly useful to align images to the root window. 487These functions are mainly useful to align images to the root window.
453 488
454Example: load an image and align it so it looks as if anchored to the 489Example: load an image and align it so it looks as if anchored to the
455background. 490background (that's exactly what C<rootalign> does btw.):
456 491
457 move -TX, -TY, load "mybg.png" 492 move -TX, -TY, keep { load "mybg.png" }
458 493
459=item TW 494=item TW
460 495
461Return the width (C<TW>) and height (C<TH>) of the terminal window (the 496Return the width (C<TW>) and height (C<TH>) of the terminal window (the
462terminal window is the full window by default, and the character area only 497terminal window is the full window by default, and the character area only
468the window size to conserve memory. 503the window size to conserve memory.
469 504
470Example: take the screen background, clip it to the window size, blur it a 505Example: take the screen background, clip it to the window size, blur it a
471bit, align it to the window position and use it as background. 506bit, align it to the window position and use it as background.
472 507
473 clip move -TX, -TY, once { blur 5, root } 508 clip move -TX, -TY, keep { blur 5, root }
474 509
475=cut 510=cut
476 511
477 sub TX() { $new->{again}{position} = 1; $x } 512 sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
478 sub TY() { $new->{again}{position} = 1; $y } 513 sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
479 sub TW() { $new->{again}{size} = 1; $w } 514 sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
480 sub TH() { $new->{again}{size} = 1; $h } 515 sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
481 516
482=item now 517=item now
483 518
484Returns the current time as (fractional) seconds since the epoch. 519Returns the current time as (fractional) seconds since the epoch.
485 520
492C<$seconds> seconds. 527C<$seconds> seconds.
493 528
494Example: load some image and rotate it according to the time of day (as if it were 529Example: load some image and rotate it according to the time of day (as if it were
495the hour pointer of a clock). Update this image every minute. 530the hour pointer of a clock). Update this image every minute.
496 531
532 again 60;
497 again 60; rotate 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png" 533 rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
498 534
499=item counter $seconds 535=item counter $seconds
500 536
501Like C<again>, but also returns an increasing counter value, starting at 537Like C<again>, but also returns an increasing counter value, starting at
5020, which might be useful for some simple animation effects. 5380, which might be useful for some simple animation effects.
504=cut 540=cut
505 541
506 sub now() { urxvt::NOW } 542 sub now() { urxvt::NOW }
507 543
508 sub again($) { 544 sub again($) {
509 $new->{again}{time} = $_[0]; 545 $frame->[FR_AGAIN]{time} = $_[0];
510 } 546 }
511 547
512 sub counter($) { 548 sub counter($) {
513 $new->{again}{time} = $_[0]; 549 $frame->[FR_AGAIN]{time} = $_[0];
514 $self->{counter} + 0 550 $frame->[FR_STATE]{counter} + 0
515 } 551 }
516 552
517=back 553=back
518 554
519=head2 SHAPE CHANGING OPERATORS 555=head2 SHAPE CHANGING OPERATORS
539assumed. 575assumed.
540 576
541Example: load an image, blur it, and clip it to the window size to save 577Example: load an image, blur it, and clip it to the window size to save
542memory. 578memory.
543 579
544 clip blur 10, load "mybg.png" 580 clip keep { blur 10, load "mybg.png" }
545 581
546=cut 582=cut
547 583
548 sub clip($;$$;$$) { 584 sub clip($;$$;$$) {
549 my $img = pop; 585 my $img = pop;
643the terminal window (or the box specified by C<$width> and C<$height> if 679the terminal window (or the box specified by C<$width> and C<$height> if
644given). 680given).
645 681
646Example: load an image and center it. 682Example: load an image and center it.
647 683
648 center pad load "mybg.png" 684 center keep { pad load "mybg.png" }
649 685
650=item rootalign $img 686=item rootalign $img
651 687
652Moves the image so that it appears glued to the screen as opposed to the 688Moves the image so that it appears glued to the screen as opposed to the
653window. This gives the illusion of a larger area behind the window. It is 689window. This gives the illusion of a larger area behind the window. It is
654exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the 690exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
655top left of the screen. 691top left of the screen.
656 692
657Example: load a background image, put it in mirror mode and root align it. 693Example: load a background image, put it in mirror mode and root align it.
658 694
659 rootalign mirror load "mybg.png" 695 rootalign keep { mirror load "mybg.png" }
660 696
661Example: take the screen background and align it, giving the illusion of 697Example: take the screen background and align it, giving the illusion of
662transparency as long as the window isn't in front of other windows. 698transparency as long as the window isn't in front of other windows.
663 699
664 rootalign root 700 rootalign root
689 725
690 sub rootalign($) { 726 sub rootalign($) {
691 move -TX, -TY, $_[0] 727 move -TX, -TY, $_[0]
692 } 728 }
693 729
694=item rotate $center_x, $center_y, $degrees 730=item rotate $center_x, $center_y, $degrees, $img
695 731
696Rotates the image by C<$degrees> degrees, counter-clockwise, around the 732Rotates the image clockwise by C<$degrees> degrees, around the point at
697pointer at C<$center_x> and C<$center_y> (specified as factor of image 733C<$center_x> and C<$center_y> (specified as factor of image width/height).
698width/height).
699 734
700#TODO# new width, height, maybe more operators?
701
702Example: rotate the image by 90 degrees 735Example: rotate the image by 90 degrees around it's center.
736
737 rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
703 738
704=cut 739=cut
705 740
706 sub rotate($$$$) { 741 sub rotate($$$$) {
707 my $img = pop; 742 my $img = pop;
810Anything that didn't fit any of the other categories, even after applying 845Anything that didn't fit any of the other categories, even after applying
811force and closing our eyes. 846force and closing our eyes.
812 847
813=over 4 848=over 4
814 849
815=item once { ... } 850=item keep { ... }
816 851
852 #TODO#
853
817This function takes a code block as argument, that is, one or more 854This operator takes a code block as argument, that is, one or more
818statements enclosed by braces. 855statements enclosed by braces.
819 856
820The trick is that this code block is only evaluated once - future calls 857The trick is that this code block is only evaluated once - future calls
821will simply return the original image (yes, it should only be used with 858will simply return the original image (yes, it should only be used with
822images). 859images).
823 860
824This can be extremely useful to avoid redoign the same slow operations 861This can be extremely useful to avoid redoing the same slow operations
825again and again- for example, if your background expression takes the root 862again and again- for example, if your background expression takes the root
826background, blurs it and then root-aligns it it would have to blur the 863background, blurs it and then root-aligns it it would have to blur the
827root background on every window move or resize. 864root background on every window move or resize.
828 865
866In fact, urxvt itself encloses the whole expression in some kind of
867C<once> block so it only is reevaluated as required.
868
829Putting the blur into a C<once> block will make sure the blur is only done 869Putting the blur into a C<once> block will make sure the blur is only done
830once: 870once:
831 871
832 rootlign once { blur 10, root } 872 rootlign keep { blur 10, root }
833 873
834This leaves the question of how to force reevaluation of the block, in 874This leaves the question of how to force reevaluation of the block,
835case the root background changes: Right now, all once blocks forget that 875in case the root background changes: If expression inside the block
836they ahve been executed before each time the root background changes (if 876is sensitive to some event (root background changes, window geometry
837the expression is sensitive to that) or when C<once_again> is called. 877changes), then it will be reevaluated automatically as needed.
838 878
839=item once_again 879=item once_again
840 880
841Resets all C<once> block as if they had never been called, i.e. on the 881Resets all C<once> block as if they had never been called, i.e. on the
842next call they will be reevaluated again. 882next call they will be reevaluated again.
843 883
844=cut 884=cut
845 885
846 sub once(&) { 886 sub once(&) {
847 my $once = $self->{once_cache}{$_[0]+0} ||= do { 887 my $id = $_[0]+0;
848 local $new->{again}; 888
849 my @res = $_[0](); 889 local $frame = $self->{frame_cache}{$id} ||= [$frame];
850 [$new->{again}, \@res] 890
891 unless ($frame->[FR_CACHE]) {
892 $frame->[FR_CACHE] = [ $_[0]() ];
893
894 my $self = $self;
895 my $frame = $frame;
896 Scalar::Util::weaken $frame;
897 $self->compile_frame ($frame, sub {
898 # clear this frame cache, also for all parents
899 for (my $frame = $frame; $frame; $frame = $frame->[0]) {
900 undef $frame->[FR_CACHE];
901 }
902
903 $self->recalculate;
851 }; 904 });
852
853 $new->{again} = {
854 %{ $new->{again} },
855 %{ $once->[0] }
856 }; 905 };
857 906
858 # in scalar context we always return the first original result, which 907 # in scalar context we always return the first original result, which
859 # is not quite how perl works. 908 # is not quite how perl works.
860 wantarray 909 wantarray
861 ? @{ $once->[1] } 910 ? @{ $frame->[FR_CACHE] }
862 : $once->[1][0] 911 : $frame->[FR_CACHE][0]
863 } 912 }
864 913
865 sub once_again() { 914 sub once_again() {
866 delete $self->{once_cache}; 915 delete $self->{frame_cache};
867 } 916 }
868 917
869=back 918=back
870 919
871=cut 920=cut
872 921
873} 922}
874 923
875sub parse_expr { 924sub parse_expr {
876 my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}"; 925 my $expr = eval
926 "sub {\n"
927 . "package urxvt::bgdsl;\n"
928 . "#line 0 'background expression'\n"
929 . "$_[0]\n"
930 . "}";
877 die if $@; 931 die if $@;
878 $expr 932 $expr
879} 933}
880 934
881# compiles a parsed expression 935# compiles a parsed expression
882sub set_expr { 936sub set_expr {
883 my ($self, $expr) = @_; 937 my ($self, $expr) = @_;
884 938
939 $self->{root} = [];
885 $self->{expr} = $expr; 940 $self->{expr} = $expr;
886 $self->recalculate; 941 $self->recalculate;
942}
943
944# takes a hash of sensitivity indicators and installs watchers
945sub compile_frame {
946 my ($self, $frame, $cb) = @_;
947
948 my $state = $frame->[urxvt::bgdsl::FR_STATE] ||= {};
949 my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
950
951 # don't keep stuff alive
952 Scalar::Util::weaken $state;
953
954 if ($again->{nested}) {
955 $state->{nested} = 1;
956 } else {
957 delete $state->{nested};
958 }
959
960 if (my $interval = $again->{time}) {
961 $state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
962 if $state->{time}[0] != $interval;
963
964 # callback *might* have changed, although we could just rule that out
965 $state->{time}[1]->cb (sub {
966 ++$state->{counter};
967 $cb->();
968 });
969 } else {
970 delete $state->{time};
971 }
972
973 if ($again->{position}) {
974 $state->{position} = $self->on (position_change => $cb);
975 } else {
976 delete $state->{position};
977 }
978
979 if ($again->{size}) {
980 $state->{size} = $self->on (size_change => $cb);
981 } else {
982 delete $state->{size};
983 }
984
985 if ($again->{rootpmap}) {
986 $state->{rootpmap} = $self->on (rootpmap_change => $cb);
987 } else {
988 delete $state->{rootpmap};
989 }
887} 990}
888 991
889# evaluate the current bg expression 992# evaluate the current bg expression
890sub recalculate { 993sub recalculate {
891 my ($arg_self) = @_; 994 my ($arg_self) = @_;
901 1004
902 $arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL; 1005 $arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
903 1006
904 # set environment to evaluate user expression 1007 # set environment to evaluate user expression
905 1008
906 local $self = $arg_self; 1009 local $self = $arg_self;
907
908 local $HOME = $ENV{HOME}; 1010 local $HOME = $ENV{HOME};
909 local $old = $self->{state}; 1011 local $frame = [];
910 local $new = my $state = $self->{state} = {};
911 1012
912 ($x, $y, $w, $h) =
913 $self->background_geometry ($self->{border}); 1013 ($x, $y, $w, $h) = $self->background_geometry ($self->{border});
914 1014
915 # evaluate user expression 1015 # evaluate user expression
916 1016
917 my $img = eval { urxvt::bgdsl::merge $self->{expr}->() }; 1017 my @img = eval { $self->{expr}->() };
918 die $@ if $@; 1018 die $@ if $@;
919 die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img"; 1019 die "background-expr did not return anything.\n" unless @img;
1020 die "background-expr: expected image(s), got something else.\n"
1021 if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
1022
1023 my $img = urxvt::bgdsl::merge @img;
1024
1025 $frame->[FR_AGAIN]{size} = 1
1026 if $img->repeat_mode != urxvt::RepeatNormal;
920 1027
921 # if the expression is sensitive to external events, prepare reevaluation then 1028 # if the expression is sensitive to external events, prepare reevaluation then
922 1029 $self->compile_frame ($frame, sub { $arg_self->recalculate });
923 my $again = delete $state->{again};
924
925 $again->{size} = 1
926 if $img->repeat_mode != urxvt::RepeatNormal;
927
928 if (my $again = $again->{time}) {
929 my $self = $self;
930 $state->{timer} = $again == $old->{again}
931 ? $old->{timer}
932 : urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
933 ++$self->{counter};
934 $self->recalculate
935 });
936 }
937
938 if ($again->{position}) {
939 $self->enable (position_change => sub { $_[0]->recalculate });
940 } else {
941 $self->disable ("position_change");
942 }
943
944 if ($again->{size}) {
945 $self->enable (size_change => sub { $_[0]->recalculate });
946 } else {
947 $self->disable ("size_change");
948 }
949
950 if ($again->{rootpmap}) {
951 $self->enable (rootpmap_change => sub {
952 delete $_[0]{once_cache}; # this will override once-block values from
953 $_[0]->recalculate;
954 });
955 } else {
956 $self->disable ("rootpmap_change");
957 }
958 1030
959 # clear stuff we no longer need 1031 # clear stuff we no longer need
960 1032
961 %$old = (); 1033# unless (%{ $frame->[FR_STATE] }) {
962
963 unless (%$again) {
964 delete $self->{state}; 1034# delete $self->{state};
965 delete $self->{expr}; 1035# delete $self->{expr};
966 } 1036# }
967 1037
968 # set background pixmap 1038 # set background pixmap
969 1039
970 $self->set_background ($img, $self->{border}); 1040 $self->set_background ($img, $self->{border});
971 $self->scr_recolour (0); 1041 $self->scr_recolour (0);

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