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Revision 1.16 by root, Wed Jun 6 11:46:11 2012 UTC vs.
Revision 1.45 by root, Sun Jun 10 11:53:32 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:%.enable:boolean:some boolean 4#:META:X_RESOURCE:%.border.:boolean:respect the terminal border
5#:META:X_RESOURCE:%.extra.*:value:extra config
6 5
7our $EXPR = 'move load "/root/pix/das_fette_schwein.jpg", repeat_wrap, X, Y'; 6#TODO: once, rootalign
8$EXPR = '
9 rotate W, H, 50, 50, counter 1/59.95, repeat_mirror,
10 clip X, Y, W, H, repeat_mirror,
11 load "/root/pix/das_fette_schwein.jpg"
12';
13$EXPR = 'solid "red"';
14#$EXPR = 'blur root, 10, 10'
15#$EXPR = 'blur move (root, -x, -y), 5, 5'
16#resize load "/root/pix/das_fette_schwein.jpg", w, h
17 7
18use Safe; 8=head1 NAME
19 9
10 background - manage terminal background
11
12=head1 SYNOPSIS
13
14 urxvt --background-expr 'background expression'
15 --background-border
16
17=head1 DESCRIPTION
18
19This extension manages the terminal background by creating a picture that
20is behind the text, replacing the normal background colour.
21
22It does so by evaluating a Perl expression that I<calculates> the image on
23the fly, for example, by grabbing the root background or loading a file.
24
25While the full power of Perl is available, the operators have been design
26to be as simple as possible.
27
28For example, to load an image and scale it to the window size, you would
29use:
30
31 urxvt --background-expr 'scale load "/path/to/mybg.png"'
32
33Or specified as a X resource:
34
35 URxvt.background-expr: scale load "/path/to/mybg.png"
36
37=head1 THEORY OF OPERATION
38
39At startup, just before the window is mapped for the first time, the
40expression is evaluated and must yield an image. The image is then
41extended as necessary to cover the whole terminal window, and is set as a
42background pixmap.
43
44If the image contains an alpha channel, then it will be used as-is in
45visuals that support alpha channels (for example, for a compositing
46manager). In other visuals, the terminal background colour will be used to
47replace any transparency.
48
49When the expression relies, directly or indirectly, on the window size,
50position, the root pixmap, or a timer, then it will be remembered. If not,
51then it will be removed.
52
53If any of the parameters that the expression relies on changes (when the
54window is moved or resized, its position or size changes; when the root
55pixmap is replaced by another one the root background changes; or when the
56timer elapses), then the expression will be evaluated again.
57
58For example, an expression such as C<scale load "$HOME/mybg.png"> scales the
59image to the window size, so it relies on the window size and will
60be reevaluated each time it is changed, but not when it moves for
61example. That ensures that the picture always fills the terminal, even
62after it's size changes.
63
64=head2 EXPRESSIONS
65
66Expressions are normal Perl expressions, in fact, they are Perl blocks -
67which means you could use multiple lines and statements:
68
69 again 3600;
70 if (localtime now)[6]) {
71 return scale load "$HOME/weekday.png";
72 } else {
73 return scale load "$HOME/sunday.png";
74 }
75
76This expression gets evaluated once per hour. It will set F<sunday.png> as
77background on Sundays, and F<weekday.png> on all other days.
78
79Fortunately, we expect that most expressions will be much simpler, with
80little Perl knowledge needed.
81
82Basically, you always start with a function that "generates" an image
83object, such as C<load>, which loads an image from disk, or C<root>, which
84returns the root window background image:
85
86 load "$HOME/mypic.png"
87
88The path is usually specified as a quoted string (the exact rules can be
89found in the L<perlop> manpage). The F<$HOME> at the beginning of the
90string is expanded to the home directory.
91
92Then you prepend one or more modifiers or filtering expressions, such as
93C<scale>:
94
95 scale load "$HOME/mypic.png"
96
97Just like a mathematical expression with functions, you should read these
98expressions from right to left, as the C<load> is evaluated first, and
99its result becomes the argument to the C<scale> function.
100
101Many operators also allow some parameters preceding the input image
102that modify its behaviour. For example, C<scale> without any additional
103arguments scales the image to size of the terminal window. If you specify
104an additional argument, it uses it as a scale factor (multiply by 100 to
105get a percentage):
106
107 scale 2, load "$HOME/mypic.png"
108
109This enlarges the image by a factor of 2 (200%). As you can see, C<scale>
110has now two arguments, the C<200> and the C<load> expression, while
111C<load> only has one argument. Arguments are separated from each other by
112commas.
113
114Scale also accepts two arguments, which are then separate factors for both
115horizontal and vertical dimensions. For example, this halves the image
116width and doubles the image height:
117
118 scale 0.5, 2, load "$HOME/mypic.png"
119
120Other effects than scalign are also readily available, for exmaple, you can
121tile the image to fill the whole window, instead of resizing it:
122
123 tile load "$HOME/mypic.png"
124
125In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator
126is kind of superfluous.
127
128Another common effect is to mirror the image, so that the same edges touch:
129
130 mirror load "$HOME/mypic.png"
131
132This is also a typical background expression:
133
134 rootalign root
135
136It first takes a snapshot of the screen background image, and then
137moves it to the upper left corner of the screen - the result is
138pseudo-transparency, as the image seems to be static while the window is
139moved around.
140
141=head2 CYCLES AND CACHING
142
143As has been mentioned before, the expression might be evaluated multiple
144times. Each time the expression is reevaluated, a new cycle is said to
145have begun. Many operators cache their results till the next cycle.
146
147For example, the C<load> operator keeps a copy of the image. If it is
148asked to load the same image on the next cycle it will not load it again,
149but return the cached copy.
150
151This only works for one cycle though, so as long as you load the same
152image every time, it will always be cached, but when you load a different
153image, it will forget about the first one.
154
155This allows you to either speed things up by keeping multiple images in
156memory, or comserve memory by loading images more often.
157
158For example, you can keep two images in memory and use a random one like
159this:
160
161 my $img1 = load "img1.png";
162 my $img2 = load "img2.png";
163 (0.5 > rand) ? $img1 : $img2
164
165Since both images are "loaded" every time the expression is evaluated,
166they are always kept in memory. Contrast this version:
167
168 my $path1 = "img1.png";
169 my $path2 = "img2.png";
170 load ((0.5 > rand) ? $path1 : $path2)
171
172Here, a path is selected randomly, and load is only called for one image,
173so keeps only one image in memory. If, on the next evaluation, luck
174decides to use the other path, then it will have to load that image again.
175
176=head1 REFERENCE
177
178=head2 COMMAND LINE SWITCHES
179
180=over 4
181
182=item --background-expr perl-expression
183
184Specifies the Perl expression to evaluate.
185
186=item --background-border
187
188By default, the expression creates an image that fills the full window,
189overwriting borders and any other areas, such as the scrollbar.
190
191Specifying this flag changes the behaviour, so that the image only
192replaces the background of the character area.
193
194=back
195
196=cut
197
198our $HOME;
20our ($bgdsl_self, $old, $new); 199our ($self, $old, $new);
21our ($l, $t, $w, $h); 200our ($x, $y, $w, $h);
22 201
23# enforce at least this interval between updates 202# enforce at least this interval between updates
24our $MIN_INTERVAL = 1/100; 203our $MIN_INTERVAL = 1/100;
25 204
26{ 205{
27 package urxvt::bgdsl; # background language 206 package urxvt::bgdsl; # background language
28 207
29 *repeat_black = \&urxvt::RepeatNone; #TODO wtf 208 use List::Util qw(min max sum shuffle);
30 *repeat_wrap = \&urxvt::RepeatNormal;
31 *repeat_pad = \&urxvt::RepeatPad;
32 *repeat_mirror = \&urxvt::RepeatReflect;
33 209
34=head2 PROVIDERS/GENERATORS 210=head2 PROVIDERS/GENERATORS
35 211
212These functions provide an image, by loading it from disk, grabbing it
213from the root screen or by simply generating it. They are used as starting
214points to get an image you can play with.
215
36=over 4 216=over 4
37 217
38=item load $path 218=item load $path
219
220Loads the image at the given C<$path>. The image is set to plane tiling
221mode.
222
223Loaded images will be cached for one cycle.
39 224
40=cut 225=cut
41 226
42 sub load($) { 227 sub load($) {
43 my ($path) = @_; 228 my ($path) = @_;
44 229
45 $new->{load}{$path} = $old->{load}{$path} || $bgdsl_self->new_img_from_file ($path); 230 $new->{load}{$path} = $old->{load}{$path} || $self->new_img_from_file ($path);
46 } 231 }
232
233=item root
234
235Returns the root window pixmap, that is, hopefully, the background image
236of your screen. The image is set to extend mode.
237
238This function makes your expression root sensitive, that means it will be
239reevaluated when the bg image changes.
240
241=cut
47 242
48 sub root() { 243 sub root() {
49 $new->{rootpmap_sensitive} = 1; 244 $new->{rootpmap_sensitive} = 1;
50 die "root op not supported, exg, we need you"; 245 die "root op not supported, exg, we need you";
51 } 246 }
52 247
248=item solid $colour
249
250=item solid $width, $height, $colour
251
252Creates a new image and completely fills it with the given colour. The
253image is set to tiling mode.
254
255If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
256useful for solid backgrounds or for use in filtering effects.
257
258=cut
259
53 sub solid($;$$) { 260 sub solid($;$$) {
261 my $colour = pop;
262
54 my $img = $bgdsl_self->new_img (urxvt::PictStandardARGB32, $_[1] || 1, $_[2] || 1); 263 my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] || 1, $_[1] || 1);
55 $img->fill ($_[0]); 264 $img->fill ($colour);
56 $img 265 $img
57 } 266 }
58 267
268=item clone $img
269
270Returns an exact copy of the image. This is useful if you want to have
271multiple copies of the same image to apply different effects to.
272
273=cut
274
275 sub clone($) {
276 $_[0]->clone
277 }
278
59=back 279=back
60 280
61=head2 OPERATORS 281=head2 TILING MODES
282
283The following operators modify the tiling mode of an image, that is, the
284way that pixels outside the image area are painted when the image is used.
62 285
63=over 4 286=over 4
64 287
65=cut 288=item tile $img
66 289
67# sub clone($) { 290Tiles the whole plane with the image and returns this new image - or in
68# $_[0]->clone 291other words, it returns a copy of the image in plane tiling mode.
292
293Example: load an image and tile it over the background, without
294resizing. The C<tile> call is superfluous because C<load> already defaults
295to tiling mode.
296
297 tile load "mybg.png"
298
299=item mirror $img
300
301Similar to tile, but reflects the image each time it uses a new copy, so
302that top edges always touch top edges, right edges always touch right
303edges and so on (with normal tiling, left edges always touch right edges
304and top always touch bottom edges).
305
306Example: load an image and mirror it over the background, avoiding sharp
307edges at the image borders at the expense of mirroring the image itself
308
309 mirror load "mybg.png"
310
311=item pad $img
312
313Takes an image and modifies it so that all pixels outside the image area
314become transparent. This mode is most useful when you want to place an
315image over another image or the background colour while leaving all
316background pixels outside the image unchanged.
317
318Example: load an image and display it in the upper left corner. The rest
319of the space is left "empty" (transparent or wahtever your compisotr does
320in alpha mode, else background colour).
321
322 pad load "mybg.png"
323
324=item extend $img
325
326Extends the image over the whole plane, using the closest pixel in the
327area outside the image. This mode is mostly useful when you more complex
328filtering operations and want the pixels outside the image to have the
329same values as the pixels near the edge.
330
331Example: just for curiosity, how does this pixel extension stuff work?
332
333 extend move 50, 50, load "mybg.png"
334
335=cut
336
337 sub pad($) {
338 my $img = $_[0]->clone;
339 $img->repeat_mode (urxvt::RepeatNone);
340 $img
69# } 341 }
70 342
343 sub tile($) {
344 my $img = $_[0]->clone;
345 $img->repeat_mode (urxvt::RepeatNormal);
346 $img
347 }
348
349 sub mirror($) {
350 my $img = $_[0]->clone;
351 $img->repeat_mode (urxvt::RepeatReflect);
352 $img
353 }
354
355 sub extend($) {
356 my $img = $_[0]->clone;
357 $img->repeat_mode (urxvt::RepeatPad);
358 $img
359 }
360
361=back
362
363=head2 VARIABLE VALUES
364
365The following functions provide variable data such as the terminal window
366dimensions. They are not (Perl-) variables, they just return stuff that
367varies. Most of them make your expression sensitive to some events, for
368example using C<TW> (terminal width) means your expression is evaluated
369again when the terminal is resized.
370
371=over 4
372
373=item TX
374
375=item TY
376
377Return the X and Y coordinates of the terminal window (the terminal
378window is the full window by default, and the character area only when in
379border-respect mode).
380
381Using these functions make your expression sensitive to window moves.
382
383These functions are mainly useful to align images to the root window.
384
385Example: load an image and align it so it looks as if anchored to the
386background.
387
388 move -TX, -TY, load "mybg.png"
389
390=item TW
391
392Return the width (C<TW>) and height (C<TH>) of the terminal window (the
393terminal window is the full window by default, and the character area only
394when in border-respect mode).
395
396Using these functions make your expression sensitive to window resizes.
397
398These functions are mainly useful to scale images, or to clip images to
399the window size to conserve memory.
400
401Example: take the screen background, clip it to the window size, blur it a
402bit, align it to the window position and use it as background.
403
404 clip move -TX, -TY, blur 5, root
405
406=cut
407
408 sub TX() { $new->{position_sensitive} = 1; $x }
409 sub TY() { $new->{position_sensitive} = 1; $y }
410 sub TW() { $new->{size_sensitive} = 1; $w }
411 sub TH() { $new->{size_sensitive} = 1; $h }
412
413=item now
414
415Returns the current time as (fractional) seconds since the epoch.
416
417Using this expression does I<not> make your expression sensitive to time,
418but the next two functions do.
419
420=item again $seconds
421
422When this function is used the expression will be reevaluated again in
423C<$seconds> seconds.
424
425Example: load some image and rotate it according to the time of day (as if it were
426the hour pointer of a clock). Update this image every minute.
427
428 again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
429
430=item counter $seconds
431
432Like C<again>, but also returns an increasing counter value, starting at
4330, which might be useful for some simple animation effects.
434
435=cut
436
437 sub now() { urxvt::NOW }
438
439 sub again($) {
440 $new->{again} = $_[0];
441 }
442
443 sub counter($) {
444 $new->{again} = $_[0];
445 $self->{counter} + 0
446 }
447
448=back
449
450=head2 SHAPE CHANGING OPERATORS
451
452The following operators modify the shape, size or position of the image.
453
454=over 4
455
456=item clip $img
457
458=item clip $width, $height, $img
459
460=item clip $x, $y, $width, $height, $img
461
462Clips an image to the given rectangle. If the rectangle is outside the
463image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is
464larger than the image, then the tiling mode defines how the extra pixels
465will be filled.
466
467If C<$x> an C<$y> are missing, then C<0> is assumed for both.
468
469If C<$width> and C<$height> are missing, then the window size will be
470assumed.
471
472Example: load an image, blur it, and clip it to the window size to save
473memory.
474
475 clip blur 10, load "mybg.png"
476
477=cut
478
71 sub clip($$$$$;$) { 479 sub clip($;$$;$$) {
480 my $img = pop;
72 my $img = pop; 481 my $h = pop || TH;
482 my $w = pop || TW;
73 $img->sub_rect ($_[0], $_[1], $_[2], $_[3], $_[4]) 483 $img->sub_rect ($_[0], $_[1], $w, $h)
484 }
485
486=item scale $img
487
488=item scale $size_factor, $img
489
490=item scale $width_factor, $height_factor, $img
491
492Scales the image by the given factors in horizontal
493(C<$width>) and vertical (C<$height>) direction.
494
495If only one factor is give, it is used for both directions.
496
497If no factors are given, scales the image to the window size without
498keeping aspect.
499
500=item resize $width, $height, $img
501
502Resizes the image to exactly C<$width> times C<$height> pixels.
503
504=item fit $img
505
506=item fit $width, $height, $img
507
508Fits the image into the given C<$width> and C<$height> without changing
509aspect, or the terminal size. That means it will be shrunk or grown until
510the whole image fits into the given area, possibly leaving borders.
511
512=item cover $img
513
514=item cover $width, $height, $img
515
516Similar to C<fit>, but shrinks or grows until all of the area is covered
517by the image, so instead of potentially leaving borders, it will cut off
518image data that doesn't fit.
519
520=cut
521
522 sub scale($;$;$) {
523 my $img = pop;
524
525 @_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
526 : @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
527 : $img->scale (TW, TH)
74 } 528 }
75 529
76 sub resize($$$) { 530 sub resize($$$) {
77 my $img = pop; 531 my $img = pop;
78 $img->scale ($_[0], $_[1]) 532 $img->scale ($_[0], $_[1])
79 } 533 }
80 534
81 # TODO: ugly 535 sub fit($;$$) {
536 my $img = pop;
537 my $w = ($_[0] || TW) / $img->w;
538 my $h = ($_[1] || TH) / $img->h;
539 scale +(min $w, $h), $img
540 }
541
542 sub cover($;$$) {
543 my $img = pop;
544 my $w = ($_[0] || TW) / $img->w;
545 my $h = ($_[1] || TH) / $img->h;
546 scale +(max $w, $h), $img
547 }
548
549=item move $dx, $dy, $img
550
551Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
552the vertical.
553
554Example: move the image right by 20 pixels and down by 30.
555
556 move 20, 30, ...
557
558=item center $img
559
560=item center $width, $height, $img
561
562Centers the image, i.e. the center of the image is moved to the center of
563the terminal window (or the box specified by C<$width> and C<$height> if
564given).
565
566=item rootalign $img
567
568Moves the image so that it appears glued to the screen as opposed to the
569window. This gives the illusion of a larger area behind the window. It is
570exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
571top left of the screen.
572
573Example: load a background image, put it in mirror mode and root align it.
574
575 rootalign mirror load "mybg.png"
576
577Example: take the screen background and align it, giving the illusion of
578transparency as long as the window isn't in front of other windows.
579
580 rootalign root
581
582=cut
583
82 sub move($$;$) { 584 sub move($$;$) {
83 my $img = pop; 585 my $img = pop->clone;
84 $img->sub_rect ( 586 $img->move ($_[0], $_[1]);
85 $_[0], $_[1], 587 $img
86 $img->w, $img->h,
87 $_[2],
88 )
89 } 588 }
90 589
590 sub center($;$$) {
591 my $img = pop;
592 my $w = $_[0] || TW;
593 my $h = $_[0] || TH;
594
595 move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
596 }
597
598 sub rootalign($) {
599 move -TX, -TY, $_[0]
600 }
601
602=back
603
604=head2 COLOUR MODIFICATIONS
605
606The following operators change the pixels of the image.
607
608=over 4
609
610=item contrast $factor, $img
611
612=item contrast $r, $g, $b, $img
613
614=item contrast $r, $g, $b, $a, $img
615
616Adjusts the I<contrast> of an image.
617
618The first form applies a single C<$factor> to red, green and blue, the
619second form applies separate factors to each colour channel, and the last
620form includes the alpha channel.
621
622Values from 0 to 1 lower the contrast, values higher than 1 increase the
623contrast.
624
625Due to limitations in the underlying XRender extension, lowering contrast
626also reduces brightness, while increasing contrast currently also
627increases brightness.
628
629=item brightness $bias, $img
630
631=item brightness $r, $g, $b, $img
632
633=item brightness $r, $g, $b, $a, $img
634
635Adjusts the brightness of an image.
636
637The first form applies a single C<$bias> to red, green and blue, the
638second form applies separate biases to each colour channel, and the last
639form includes the alpha channel.
640
641Values less than 0 reduce brightness, while values larger than 0 increase
642it. Useful range is from -1 to 1 - the former results in a black, the
643latter in a white picture.
644
645Due to idiosynchrasies in the underlying XRender extension, biases less
646than zero can be I<very> slow.
647
648=cut
649
650 sub contrast($$;$$;$) {
651 my $img = pop;
652 my ($r, $g, $b, $a) = @_;
653
654 ($g, $b) = ($r, $r) if @_ < 4;
655 $a = 1 if @_ < 5;
656
657 $img = $img->clone;
658 $img->contrast ($r, $g, $b, $a);
659 $img
660 }
661
662 sub brightness($$;$$;$) {
663 my $img = pop;
664 my ($r, $g, $b, $a) = @_;
665
666 ($g, $b) = ($r, $r) if @_ < 4;
667 $a = 1 if @_ < 5;
668
669 $img = $img->clone;
670 $img->brightness ($r, $g, $b, $a);
671 $img
672 }
673
674=item blur $radius, $img
675
676=item blur $radius_horz, $radius_vert, $img
677
678Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
679can also be specified separately.
680
681Blurring is often I<very> slow, at least compared or other
682operators. Larger blur radii are slower than smaller ones, too, so if you
683don't want to freeze your screen for long times, start experimenting with
684low values for radius (<5).
685
686=cut
687
688 sub blur($$;$) {
689 my $img = pop;
690 $img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
691 }
692
693=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
694
695Rotates the image by C<$degrees> degrees, counter-clockwise, around the
696pointer at C<$center_x> and C<$center_y> (specified as factor of image
697width/height), generating a new image with width C<$new_width> and height
698C<$new_height>.
699
700#TODO# new width, height, maybe more operators?
701
702Example: rotate the image by 90 degrees
703
704=cut
705
91 sub rotate($$$$$$;$) { 706 sub rotate($$$$$$) {
92 my $img = pop; 707 my $img = pop;
93 $img->rotate ( 708 $img->rotate (
94 $_[0], 709 $_[0],
95 $_[1], 710 $_[1],
96 $_[2] * $img->w * .01, 711 $_[2] * $img->w,
97 $_[3] * $img->h * .01, 712 $_[3] * $img->h,
98 $_[4] * (3.14159265 / 180), 713 $_[4] * (3.14159265 / 180),
99 $_[5],
100 ) 714 )
101 }
102
103 sub blur($$$) {
104 my ($rh, $rv, $img) = @_;
105
106 $img->blur ($rh, $rv);
107 }
108
109 sub contrast($$;$$;$) {
110 my $img = pop;
111 my ($r, $g, $b, $a) = @_;
112
113 ($g, $b) = ($r, $r) if @_ < 4;
114 $a = 1 if @_ < 5;
115
116 $img = $img->clone;
117 $img->contrast ($r, $g, $b, $a);
118 $img
119 }
120
121 sub brightness($$;$$;$) {
122 my $img = pop;
123 my ($r, $g, $b, $a) = @_;
124
125 ($g, $b) = ($r, $r) if @_ < 4;
126 $a = 1 if @_ < 5;
127
128 $img = $img->clone;
129 $img->brightness ($r, $g, $b, $a);
130 $img
131 }
132
133 sub X() { $new->{position_sensitive} = 1; $l }
134 sub Y() { $new->{position_sensitive} = 1; $t }
135 sub W() { $new->{size_sensitive} = 1; $w }
136 sub H() { $new->{size_sensitive} = 1; $h }
137
138 sub now() { urxvt::NOW }
139
140 sub again($) {
141 $new->{again} = $_[0];
142 }
143
144 sub counter($) {
145 $new->{again} = $_[0];
146 $bgdsl_self->{counter} + 0
147 } 715 }
148 716
149=back 717=back
150 718
151=cut 719=cut
166 $self->recalculate; 734 $self->recalculate;
167} 735}
168 736
169# evaluate the current bg expression 737# evaluate the current bg expression
170sub recalculate { 738sub recalculate {
171 my ($self) = @_; 739 my ($arg_self) = @_;
172 740
173 # rate limit evaluation 741 # rate limit evaluation
174 742
175 if ($self->{next_refresh} > urxvt::NOW) { 743 if ($arg_self->{next_refresh} > urxvt::NOW) {
176 $self->{next_refresh_timer} = urxvt::timer->new->after ($self->{next_refresh} - urxvt::NOW)->cb (sub { 744 $arg_self->{next_refresh_timer} = urxvt::timer->new->after ($arg_self->{next_refresh} - urxvt::NOW)->cb (sub {
177 $self->recalculate; 745 $arg_self->recalculate;
178 }); 746 });
179 return; 747 return;
180 } 748 }
181 749
182 $self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL; 750 $arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
183 751
184 # set environment to evaluate user expression 752 # set environment to evaluate user expression
185 753
186 local $bgdsl_self = $self; 754 local $self = $arg_self;
187 755
756 local $HOME = $ENV{HOME};
188 local $old = $self->{state}; 757 local $old = $self->{state};
189 local $new = my $state = $self->{state} = {}; 758 local $new = my $state = $self->{state} = {};
190 759
191 ($l, $t, $w, $h) = 760 ($x, $y, $w, $h) =
192 $self->get_geometry; 761 $self->background_geometry ($self->{border});
193 762
194 # evaluate user expression 763 # evaluate user expression
195 764
196 my $img = eval { $self->{expr}->() }; 765 my $img = eval { $self->{expr}->() };
197 warn $@ if $@;#d# 766 warn $@ if $@;#d#
198 die if !UNIVERSAL::isa $img, "urxvt::img"; 767 die if !UNIVERSAL::isa $img, "urxvt::img";
199 768
769 $state->{size_sensitive} = 1
770 if $img->repeat_mode != urxvt::RepeatNormal;
771
200 # if the expression is sensitive to external events, prepare reevaluation then 772 # if the expression is sensitive to external events, prepare reevaluation then
201 773
202 my $repeat; 774 my $repeat;
203 775
204 if (my $again = $state->{again}) { 776 if (my $again = $state->{again}) {
205 $repeat = 1; 777 $repeat = 1;
778 my $self = $self;
206 $state->{timer} = $again == $old->{again} 779 $state->{timer} = $again == $old->{again}
207 ? $old->{timer} 780 ? $old->{timer}
208 : urxvt::timer->new->after ($again)->interval ($again)->cb (sub { 781 : urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
209 ++$self->{counter}; 782 ++$self->{counter};
210 $self->recalculate 783 $self->recalculate
239 unless ($repeat) { 812 unless ($repeat) {
240 delete $self->{state}; 813 delete $self->{state};
241 delete $self->{expr}; 814 delete $self->{expr};
242 } 815 }
243 816
244 # prepare and set background pixmap 817 # set background pixmap
245 818
246 $img = $img->sub_rect (0, 0, $w, $h)
247 if $img->w != $w || $img->h != $h;
248
249 $self->set_background ($img); 819 $self->set_background ($img, $self->{border});
250 $self->scr_recolour (0); 820 $self->scr_recolour (0);
251 $self->want_refresh; 821 $self->want_refresh;
252} 822}
253 823
254sub on_start { 824sub on_start {
255 my ($self) = @_; 825 my ($self) = @_;
256 826
257 warn $self->x_resource ("background.enable"); 827 my $expr = $self->x_resource ("background.expr")
828 or return;
258 829
259 $self->set_expr (parse_expr $EXPR); 830 $self->set_expr (parse_expr $expr);
831 $self->{border} = $self->x_resource_boolean ("background.border");
260 832
261 () 833 ()
262} 834}
263 835

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