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Revision 1.17 by root, Wed Jun 6 14:34:03 2012 UTC vs.
Revision 1.50 by root, Sun Jun 10 17:31:53 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 5#:META:X_RESOURCE:%.interval:seconds:minimum time between updates
6 6
7our $EXPR = 'move load "/root/pix/das_fette_schwein.jpg", repeat_wrap, X, Y'; 7=head1 NAME
8$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 8
18use Safe; 9 background - manage terminal background
19 10
11=head1 SYNOPSIS
12
13 urxvt --background-expr 'background expression'
14 --background-border
15 --background-interval seconds
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=item --background-interval seconds
195
196Since some operations in the underlying XRender extension can effetively
197freeze your X-server for prolonged time, this extension enforces a minimum
198time between updates, which is normally about 0.1 seconds.
199
200If you want to do updates more often, you can decrease this safety
201interval with this switch.
202
203=back
204
205=cut
206
207our %_IMGCACHE;
208our $HOME;
20our ($bgdsl_self, $old, $new); 209our ($self, $old, $new);
21our ($l, $t, $w, $h); 210our ($x, $y, $w, $h);
22 211
23# enforce at least this interval between updates 212# enforce at least this interval between updates
24our $MIN_INTERVAL = 1/100; 213our $MIN_INTERVAL = 6/59.951;
25 214
26{ 215{
27 package urxvt::bgdsl; # background language 216 package urxvt::bgdsl; # background language
28 217
29 *repeat_empty = \&urxvt::RepeatNone; 218 use List::Util qw(min max sum shuffle);
30 *repeat_tile = \&urxvt::RepeatNormal;
31 *repeat_pad = \&urxvt::RepeatPad;
32 *repeat_mirror = \&urxvt::RepeatReflect;
33 219
34=head2 PROVIDERS/GENERATORS 220=head2 PROVIDERS/GENERATORS
35 221
222These functions provide an image, by loading it from disk, grabbing it
223from the root screen or by simply generating it. They are used as starting
224points to get an image you can play with.
225
36=over 4 226=over 4
37 227
38=item load $path 228=item load $path
229
230Loads the image at the given C<$path>. The image is set to plane tiling
231mode.
232
233Loaded images will be cached for one cycle.
39 234
40=cut 235=cut
41 236
42 sub load($) { 237 sub load($) {
43 my ($path) = @_; 238 my ($path) = @_;
44 239
45 $new->{load}{$path} = $old->{load}{$path} || $bgdsl_self->new_img_from_file ($path); 240 $new->{load}{$path} = $old->{load}{$path} || $self->new_img_from_file ($path);
46 } 241 }
242
243=item root
244
245Returns the root window pixmap, that is, hopefully, the background image
246of your screen. The image is set to extend mode.
247
248This function makes your expression root sensitive, that means it will be
249reevaluated when the bg image changes.
250
251=cut
47 252
48 sub root() { 253 sub root() {
49 $new->{rootpmap_sensitive} = 1; 254 $new->{rootpmap_sensitive} = 1;
50 die "root op not supported, exg, we need you"; 255 die "root op not supported, exg, we need you";
51 } 256 }
52 257
258=item solid $colour
259
260=item solid $width, $height, $colour
261
262Creates a new image and completely fills it with the given colour. The
263image is set to tiling mode.
264
265If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
266useful for solid backgrounds or for use in filtering effects.
267
268=cut
269
53 sub solid($;$$) { 270 sub solid($;$$) {
271 my $colour = pop;
272
54 my $img = $bgdsl_self->new_img (urxvt::PictStandardARGB32, $_[1] || 1, $_[2] || 1); 273 my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] || 1, $_[1] || 1);
55 $img->fill ($_[0]); 274 $img->fill ($colour);
56 $img 275 $img
57 } 276 }
58 277
278=item clone $img
279
280Returns an exact copy of the image. This is useful if you want to have
281multiple copies of the same image to apply different effects to.
282
283=cut
284
285 sub clone($) {
286 $_[0]->clone
287 }
288
59=back 289=back
60 290
61=head2 OPERATORS 291=head2 TILING MODES
292
293The following operators modify the tiling mode of an image, that is, the
294way that pixels outside the image area are painted when the image is used.
62 295
63=over 4 296=over 4
64 297
65=cut 298=item tile $img
66 299
67# sub clone($) { 300Tiles the whole plane with the image and returns this new image - or in
68# $_[0]->clone 301other words, it returns a copy of the image in plane tiling mode.
302
303Example: load an image and tile it over the background, without
304resizing. The C<tile> call is superfluous because C<load> already defaults
305to tiling mode.
306
307 tile load "mybg.png"
308
309=item mirror $img
310
311Similar to tile, but reflects the image each time it uses a new copy, so
312that top edges always touch top edges, right edges always touch right
313edges and so on (with normal tiling, left edges always touch right edges
314and top always touch bottom edges).
315
316Example: load an image and mirror it over the background, avoiding sharp
317edges at the image borders at the expense of mirroring the image itself
318
319 mirror load "mybg.png"
320
321=item pad $img
322
323Takes an image and modifies it so that all pixels outside the image area
324become transparent. This mode is most useful when you want to place an
325image over another image or the background colour while leaving all
326background pixels outside the image unchanged.
327
328Example: load an image and display it in the upper left corner. The rest
329of the space is left "empty" (transparent or wahtever your compisotr does
330in alpha mode, else background colour).
331
332 pad load "mybg.png"
333
334=item extend $img
335
336Extends the image over the whole plane, using the closest pixel in the
337area outside the image. This mode is mostly useful when you more complex
338filtering operations and want the pixels outside the image to have the
339same values as the pixels near the edge.
340
341Example: just for curiosity, how does this pixel extension stuff work?
342
343 extend move 50, 50, load "mybg.png"
344
345=cut
346
347 sub pad($) {
348 my $img = $_[0]->clone;
349 $img->repeat_mode (urxvt::RepeatNone);
350 $img
69# } 351 }
70 352
353 sub tile($) {
354 my $img = $_[0]->clone;
355 $img->repeat_mode (urxvt::RepeatNormal);
356 $img
357 }
358
359 sub mirror($) {
360 my $img = $_[0]->clone;
361 $img->repeat_mode (urxvt::RepeatReflect);
362 $img
363 }
364
365 sub extend($) {
366 my $img = $_[0]->clone;
367 $img->repeat_mode (urxvt::RepeatPad);
368 $img
369 }
370
371=back
372
373=head2 VARIABLE VALUES
374
375The following functions provide variable data such as the terminal window
376dimensions. They are not (Perl-) variables, they just return stuff that
377varies. Most of them make your expression sensitive to some events, for
378example using C<TW> (terminal width) means your expression is evaluated
379again when the terminal is resized.
380
381=over 4
382
383=item TX
384
385=item TY
386
387Return the X and Y coordinates of the terminal window (the terminal
388window is the full window by default, and the character area only when in
389border-respect mode).
390
391Using these functions make your expression sensitive to window moves.
392
393These functions are mainly useful to align images to the root window.
394
395Example: load an image and align it so it looks as if anchored to the
396background.
397
398 move -TX, -TY, load "mybg.png"
399
400=item TW
401
402Return the width (C<TW>) and height (C<TH>) of the terminal window (the
403terminal window is the full window by default, and the character area only
404when in border-respect mode).
405
406Using these functions make your expression sensitive to window resizes.
407
408These functions are mainly useful to scale images, or to clip images to
409the window size to conserve memory.
410
411Example: take the screen background, clip it to the window size, blur it a
412bit, align it to the window position and use it as background.
413
414 clip move -TX, -TY, blur 5, root
415
416=cut
417
418 sub TX() { $new->{position_sensitive} = 1; $x }
419 sub TY() { $new->{position_sensitive} = 1; $y }
420 sub TW() { $new->{size_sensitive} = 1; $w }
421 sub TH() { $new->{size_sensitive} = 1; $h }
422
423=item now
424
425Returns the current time as (fractional) seconds since the epoch.
426
427Using this expression does I<not> make your expression sensitive to time,
428but the next two functions do.
429
430=item again $seconds
431
432When this function is used the expression will be reevaluated again in
433C<$seconds> seconds.
434
435Example: load some image and rotate it according to the time of day (as if it were
436the hour pointer of a clock). Update this image every minute.
437
438 again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
439
440=item counter $seconds
441
442Like C<again>, but also returns an increasing counter value, starting at
4430, which might be useful for some simple animation effects.
444
445=cut
446
447 sub now() { urxvt::NOW }
448
449 sub again($) {
450 $new->{again} = $_[0];
451 }
452
453 sub counter($) {
454 $new->{again} = $_[0];
455 $self->{counter} + 0
456 }
457
458=back
459
460=head2 SHAPE CHANGING OPERATORS
461
462The following operators modify the shape, size or position of the image.
463
464=over 4
465
466=item clip $img
467
468=item clip $width, $height, $img
469
470=item clip $x, $y, $width, $height, $img
471
472Clips an image to the given rectangle. If the rectangle is outside the
473image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is
474larger than the image, then the tiling mode defines how the extra pixels
475will be filled.
476
477If C<$x> an C<$y> are missing, then C<0> is assumed for both.
478
479If C<$width> and C<$height> are missing, then the window size will be
480assumed.
481
482Example: load an image, blur it, and clip it to the window size to save
483memory.
484
485 clip blur 10, load "mybg.png"
486
487=cut
488
71 sub clip($$$$$;$) { 489 sub clip($;$$;$$) {
490 my $img = pop;
72 my $img = pop; 491 my $h = pop || TH;
492 my $w = pop || TW;
73 $img->sub_rect ($_[0], $_[1], $_[2], $_[3], $_[4]) 493 $img->sub_rect ($_[0], $_[1], $w, $h)
494 }
495
496=item scale $img
497
498=item scale $size_factor, $img
499
500=item scale $width_factor, $height_factor, $img
501
502Scales the image by the given factors in horizontal
503(C<$width>) and vertical (C<$height>) direction.
504
505If only one factor is give, it is used for both directions.
506
507If no factors are given, scales the image to the window size without
508keeping aspect.
509
510=item resize $width, $height, $img
511
512Resizes the image to exactly C<$width> times C<$height> pixels.
513
514=item fit $img
515
516=item fit $width, $height, $img
517
518Fits the image into the given C<$width> and C<$height> without changing
519aspect, or the terminal size. That means it will be shrunk or grown until
520the whole image fits into the given area, possibly leaving borders.
521
522=item cover $img
523
524=item cover $width, $height, $img
525
526Similar to C<fit>, but shrinks or grows until all of the area is covered
527by the image, so instead of potentially leaving borders, it will cut off
528image data that doesn't fit.
529
530=cut
531
532 sub scale($;$;$) {
533 my $img = pop;
534
535 @_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
536 : @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
537 : $img->scale (TW, TH)
74 } 538 }
75 539
76 sub resize($$$) { 540 sub resize($$$) {
77 my $img = pop; 541 my $img = pop;
78 $img->scale ($_[0], $_[1]) 542 $img->scale ($_[0], $_[1])
79 } 543 }
80 544
81 # TODO: ugly 545 sub fit($;$$) {
546 my $img = pop;
547 my $w = ($_[0] || TW) / $img->w;
548 my $h = ($_[1] || TH) / $img->h;
549 scale +(min $w, $h), $img
550 }
551
552 sub cover($;$$) {
553 my $img = pop;
554 my $w = ($_[0] || TW) / $img->w;
555 my $h = ($_[1] || TH) / $img->h;
556 scale +(max $w, $h), $img
557 }
558
559=item move $dx, $dy, $img
560
561Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
562the vertical.
563
564Example: move the image right by 20 pixels and down by 30.
565
566 move 20, 30, ...
567
568=item align $xalign, $yalign, $img
569
570Aligns the image according to a factor - C<0> means the image is moved to
571the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
572exactly centered and C<1> means it touches the right or bottom edge.
573
574Example: remove any visible border around an image, center it vertically but move
575it to the right hand side.
576
577 align 1, 0.5, pad $img
578
579=item center $img
580
581=item center $width, $height, $img
582
583Centers the image, i.e. the center of the image is moved to the center of
584the terminal window (or the box specified by C<$width> and C<$height> if
585given).
586
587Example: load an image and center it.
588
589 center pad load "mybg.png"
590
591=item rootalign $img
592
593Moves the image so that it appears glued to the screen as opposed to the
594window. This gives the illusion of a larger area behind the window. It is
595exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
596top left of the screen.
597
598Example: load a background image, put it in mirror mode and root align it.
599
600 rootalign mirror load "mybg.png"
601
602Example: take the screen background and align it, giving the illusion of
603transparency as long as the window isn't in front of other windows.
604
605 rootalign root
606
607=cut
608
82 sub move($$;$) { 609 sub move($$;$) {
83 my $img = pop; 610 my $img = pop->clone;
84 $img->sub_rect ( 611 $img->move ($_[0], $_[1]);
85 $_[0], $_[1], 612 $img
86 $img->w, $img->h,
87 $_[2],
88 )
89 } 613 }
90 614
615 sub align($;$$) {
616 my $img = pop;
617
618 move $_[0] * (TW - $img->w),
619 $_[1] * (TH - $img->h),
620 $img
621 }
622
623 sub center($;$$) {
624 my $img = pop;
625 my $w = $_[0] || TW;
626 my $h = $_[1] || TH;
627
628 move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
629 }
630
631 sub rootalign($) {
632 move -TX, -TY, $_[0]
633 }
634
635=back
636
637=head2 COLOUR MODIFICATIONS
638
639The following operators change the pixels of the image.
640
641=over 4
642
643=item contrast $factor, $img
644
645=item contrast $r, $g, $b, $img
646
647=item contrast $r, $g, $b, $a, $img
648
649Adjusts the I<contrast> of an image.
650
651The first form applies a single C<$factor> to red, green and blue, the
652second form applies separate factors to each colour channel, and the last
653form includes the alpha channel.
654
655Values from 0 to 1 lower the contrast, values higher than 1 increase the
656contrast.
657
658Due to limitations in the underlying XRender extension, lowering contrast
659also reduces brightness, while increasing contrast currently also
660increases brightness.
661
662=item brightness $bias, $img
663
664=item brightness $r, $g, $b, $img
665
666=item brightness $r, $g, $b, $a, $img
667
668Adjusts the brightness of an image.
669
670The first form applies a single C<$bias> to red, green and blue, the
671second form applies separate biases to each colour channel, and the last
672form includes the alpha channel.
673
674Values less than 0 reduce brightness, while values larger than 0 increase
675it. Useful range is from -1 to 1 - the former results in a black, the
676latter in a white picture.
677
678Due to idiosynchrasies in the underlying XRender extension, biases less
679than zero can be I<very> slow.
680
681=cut
682
683 sub contrast($$;$$;$) {
684 my $img = pop;
685 my ($r, $g, $b, $a) = @_;
686
687 ($g, $b) = ($r, $r) if @_ < 3;
688 $a = 1 if @_ < 4;
689
690 $img = $img->clone;
691 $img->contrast ($r, $g, $b, $a);
692 $img
693 }
694
695 sub brightness($$;$$;$) {
696 my $img = pop;
697 my ($r, $g, $b, $a) = @_;
698
699 ($g, $b) = ($r, $r) if @_ < 3;
700 $a = 1 if @_ < 4;
701
702 $img = $img->clone;
703 $img->brightness ($r, $g, $b, $a);
704 $img
705 }
706
707=item blur $radius, $img
708
709=item blur $radius_horz, $radius_vert, $img
710
711Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
712can also be specified separately.
713
714Blurring is often I<very> slow, at least compared or other
715operators. Larger blur radii are slower than smaller ones, too, so if you
716don't want to freeze your screen for long times, start experimenting with
717low values for radius (<5).
718
719=cut
720
721 sub blur($$;$) {
722 my $img = pop;
723 $img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
724 }
725
726=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
727
728Rotates the image by C<$degrees> degrees, counter-clockwise, around the
729pointer at C<$center_x> and C<$center_y> (specified as factor of image
730width/height), generating a new image with width C<$new_width> and height
731C<$new_height>.
732
733#TODO# new width, height, maybe more operators?
734
735Example: rotate the image by 90 degrees
736
737=cut
738
91 sub rotate($$$$$$;$) { 739 sub rotate($$$$$$) {
92 my $img = pop; 740 my $img = pop;
93 $img->rotate ( 741 $img->rotate (
94 $_[0], 742 $_[0],
95 $_[1], 743 $_[1],
96 $_[2] * $img->w * .01, 744 $_[2] * $img->w,
97 $_[3] * $img->h * .01, 745 $_[3] * $img->h,
98 $_[4] * (3.14159265 / 180), 746 $_[4] * (3.14159265 / 180),
99 $_[5],
100 ) 747 )
101 }
102
103 sub blur($$$) {
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 } 748 }
148 749
149=back 750=back
150 751
151=cut 752=cut
166 $self->recalculate; 767 $self->recalculate;
167} 768}
168 769
169# evaluate the current bg expression 770# evaluate the current bg expression
170sub recalculate { 771sub recalculate {
171 my ($self) = @_; 772 my ($arg_self) = @_;
172 773
173 # rate limit evaluation 774 # rate limit evaluation
174 775
175 if ($self->{next_refresh} > urxvt::NOW) { 776 if ($arg_self->{next_refresh} > urxvt::NOW) {
176 $self->{next_refresh_timer} = urxvt::timer->new->after ($self->{next_refresh} - urxvt::NOW)->cb (sub { 777 $arg_self->{next_refresh_timer} = urxvt::timer->new->after ($arg_self->{next_refresh} - urxvt::NOW)->cb (sub {
177 $self->recalculate; 778 $arg_self->recalculate;
178 }); 779 });
179 return; 780 return;
180 } 781 }
181 782
182 $self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL; 783 $arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
183 784
184 # set environment to evaluate user expression 785 # set environment to evaluate user expression
185 786
186 local $bgdsl_self = $self; 787 local $self = $arg_self;
187 788
789 local $HOME = $ENV{HOME};
188 local $old = $self->{state}; 790 local $old = $self->{state};
189 local $new = my $state = $self->{state} = {}; 791 local $new = my $state = $self->{state} = {};
190 792
191 ($l, $t, $w, $h) = 793 ($x, $y, $w, $h) =
192 $self->get_geometry; 794 $self->background_geometry ($self->{border});
193 795
194 # evaluate user expression 796 # evaluate user expression
195 797
196 my $img = eval { $self->{expr}->() }; 798 my $img = eval { $self->{expr}->() };
197 warn $@ if $@;#d# 799 warn $@ if $@;#d#
198 die if !UNIVERSAL::isa $img, "urxvt::img"; 800 die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";
801
802 $state->{size_sensitive} = 1
803 if $img->repeat_mode != urxvt::RepeatNormal;
199 804
200 # if the expression is sensitive to external events, prepare reevaluation then 805 # if the expression is sensitive to external events, prepare reevaluation then
201 806
202 my $repeat; 807 my $repeat;
203 808
204 if (my $again = $state->{again}) { 809 if (my $again = $state->{again}) {
205 $repeat = 1; 810 $repeat = 1;
811 my $self = $self;
206 $state->{timer} = $again == $old->{again} 812 $state->{timer} = $again == $old->{again}
207 ? $old->{timer} 813 ? $old->{timer}
208 : urxvt::timer->new->after ($again)->interval ($again)->cb (sub { 814 : urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
209 ++$self->{counter}; 815 ++$self->{counter};
210 $self->recalculate 816 $self->recalculate
239 unless ($repeat) { 845 unless ($repeat) {
240 delete $self->{state}; 846 delete $self->{state};
241 delete $self->{expr}; 847 delete $self->{expr};
242 } 848 }
243 849
244 # prepare and set background pixmap 850 # set background pixmap
245 851
246 $img = $img->sub_rect (0, 0, $w, $h)
247 if $img->w != $w || $img->h != $h;
248
249 $self->set_background ($img); 852 $self->set_background ($img, $self->{border});
250 $self->scr_recolour (0); 853 $self->scr_recolour (0);
251 $self->want_refresh; 854 $self->want_refresh;
252} 855}
253 856
254sub on_start { 857sub on_start {
255 my ($self) = @_; 858 my ($self) = @_;
256 859
860 my $expr = $self->x_resource ("%.expr")
861 or return;
862
863 $self->has_render
864 or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
865
257 $self->set_expr (parse_expr $EXPR); 866 $self->set_expr (parse_expr $expr);
867 $self->{border} = $self->x_resource_boolean ("%.border");
868
869 $MIN_INTERVAL = $self->x_resource ("%.interval");
258 870
259 () 871 ()
260} 872}
261 873

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