1 |
#! perl |
2 |
|
3 |
#:META:X_RESOURCE:%.expr:string:background expression |
4 |
#:META:X_RESOURCE:%.border.:boolean:respect the terminal border |
5 |
|
6 |
#TODO: once, rootalign |
7 |
|
8 |
=head1 background - manage terminal background |
9 |
|
10 |
=head2 SYNOPSIS |
11 |
|
12 |
urxvt --background-expr 'background expression' |
13 |
--background-border |
14 |
|
15 |
=head2 DESCRIPTION |
16 |
|
17 |
This extension manages the terminal background by creating a picture that |
18 |
is behind the text, replacing the normal background colour. |
19 |
|
20 |
It does so by evaluating a Perl expression that I<calculates> the image on |
21 |
the fly, for example, by grabbing the root background or loading a file. |
22 |
|
23 |
While the full power of Perl is available, the operators have been design |
24 |
to be as simple as possible. |
25 |
|
26 |
For example, to load an image and scale it to the window size, you would |
27 |
use: |
28 |
|
29 |
urxvt --background-expr 'scale load "/path/to/mybg.png"' |
30 |
|
31 |
Or specified as a X resource: |
32 |
|
33 |
URxvt.background-expr: scale load "/path/to/mybg.png" |
34 |
|
35 |
=head2 THEORY OF OPERATION |
36 |
|
37 |
At startup, just before the window is mapped for the first time, the |
38 |
expression is evaluated and must yield an image. The image is then |
39 |
extended as necessary to cover the whole terminal window, and is set as a |
40 |
background pixmap. |
41 |
|
42 |
If the image contains an alpha channel, then it will be used as-is in |
43 |
visuals that support alpha channels (for example, for a compositing |
44 |
manager). In other visuals, the terminal background colour will be used to |
45 |
replace any transparency. |
46 |
|
47 |
When the expression relies, directly or indirectly, on the window size, |
48 |
position, the root pixmap, or a timer, then it will be remembered. If not, |
49 |
then it will be removed. |
50 |
|
51 |
If any of the parameters that the expression relies on changes (when the |
52 |
window is moved or resized, its position or size changes; when the root |
53 |
pixmap is replaced by another one the root background changes; or when the |
54 |
timer elapses), then the expression will be evaluated again. |
55 |
|
56 |
For example, an expression such as C<scale load "$HOME/mybg.png"> scales the |
57 |
image to the window size, so it relies on the window size and will |
58 |
be reevaluated each time it is changed, but not when it moves for |
59 |
example. That ensures that the picture always fills the terminal, even |
60 |
after it's size changes. |
61 |
|
62 |
=head3 EXPRESSIONS |
63 |
|
64 |
Expressions are normal Perl expressions, in fact, they are Perl blocks - |
65 |
which means you could use multiple lines and statements: |
66 |
|
67 |
again 3600; |
68 |
if (localtime now)[6]) { |
69 |
return scale load "$HOME/weekday.png"; |
70 |
} else { |
71 |
return scale load "$HOME/sunday.png"; |
72 |
} |
73 |
|
74 |
This expression gets evaluated once per hour. It will set F<sunday.png> as |
75 |
background on Sundays, and F<weekday.png> on all other days. |
76 |
|
77 |
Fortunately, we expect that most expressions will be much simpler, with |
78 |
little Perl knowledge needed. |
79 |
|
80 |
Basically, you always start with a function that "generates" an image |
81 |
object, such as C<load>, which loads an image from disk, or C<root>, which |
82 |
returns the root window background image: |
83 |
|
84 |
load "$HOME/mypic.png" |
85 |
|
86 |
The path is usually specified as a quoted string (the exact rules can be |
87 |
found in the L<perlop> manpage). The F<$HOME> at the beginning of the |
88 |
string is expanded to the home directory. |
89 |
|
90 |
Then you prepend one or more modifiers or filtering expressions, such as |
91 |
C<scale>: |
92 |
|
93 |
scale load "$HOME/mypic.png" |
94 |
|
95 |
Just like a mathematical expression with functions, you should read these |
96 |
expressions from right to left, as the C<load> is evaluated first, and |
97 |
its result becomes the argument to the C<scale> function. |
98 |
|
99 |
Many operators also allow some parameters preceding the input image |
100 |
that modify its behaviour. For example, C<scale> without any additional |
101 |
arguments scales the image to size of the terminal window. If you specify |
102 |
an additional argument, it uses it as a percentage: |
103 |
|
104 |
scale 200, load "$HOME/mypic.png" |
105 |
|
106 |
This enlarges the image by a factor of 2 (200%). As you can see, C<scale> |
107 |
has now two arguments, the C<200> and the C<load> expression, while |
108 |
C<load> only has one argument. Arguments are separated from each other by |
109 |
commas. |
110 |
|
111 |
Scale also accepts two arguments, which are then separate factors for both |
112 |
horizontal and vertical dimensions. For example, this halves the image |
113 |
width and doubles the image height: |
114 |
|
115 |
scale 50, 200, load "$HOME/mypic.png" |
116 |
|
117 |
Other effects than scalign are also readily available, for exmaple, you can |
118 |
tile the image to fill the whole window, instead of resizing it: |
119 |
|
120 |
tile load "$HOME/mypic.png" |
121 |
|
122 |
In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator |
123 |
is kind of superfluous. |
124 |
|
125 |
Another common effect is to mirror the image, so that the same edges touch: |
126 |
|
127 |
mirror load "$HOME/mypic.png" |
128 |
|
129 |
This is also a typical background expression: |
130 |
|
131 |
rootalign root |
132 |
|
133 |
It first takes a snapshot of the screen background image, and then |
134 |
moves it to the upper left corner of the screen - the result is |
135 |
pseudo-transparency, as the image seems to be static while the window is |
136 |
moved around. |
137 |
|
138 |
=head3 CYCLES AND CACHING |
139 |
|
140 |
As has been mentioned before, the expression might be evaluated multiple |
141 |
times. Each time the expression is reevaluated, a new cycle is said to |
142 |
have begun. Many operators cache their results till the next cycle. |
143 |
|
144 |
For example, the C<load> operator keeps a copy of the image. If it is |
145 |
asked to load the same image on the next cycle it will not load it again, |
146 |
but return the cached copy. |
147 |
|
148 |
This only works for one cycle though, so as long as you load the same |
149 |
image every time, it will always be cached, but when you load a different |
150 |
image, it will forget about the first one. |
151 |
|
152 |
This allows you to either speed things up by keeping multiple images in |
153 |
memory, or comserve memory by loading images more often. |
154 |
|
155 |
For example, you can keep two images in memory and use a random one like |
156 |
this: |
157 |
|
158 |
my $img1 = load "img1.png"; |
159 |
my $img2 = load "img2.png"; |
160 |
(0.5 > rand) ? $img1 : $img2 |
161 |
|
162 |
Since both images are "loaded" every time the expression is evaluated, |
163 |
they are always kept in memory. Contrast this version: |
164 |
|
165 |
my $path1 = "img1.png"; |
166 |
my $path2 = "img2.png"; |
167 |
load ((0.5 > rand) ? $path1 : $path2) |
168 |
|
169 |
Here, a path is selected randomly, and load is only called for one image, |
170 |
so keeps only one image in memory. If, on the next evaluation, luck |
171 |
decides to use the other path, then it will have to load that image again. |
172 |
|
173 |
=head2 REFERENCE |
174 |
|
175 |
=head3 COMMAND LINE SWITCHES |
176 |
|
177 |
=over 4 |
178 |
|
179 |
=item --background-expr perl-expression |
180 |
|
181 |
Specifies the Perl expression to evaluate. |
182 |
|
183 |
=item --background-border |
184 |
|
185 |
By default, the expression creates an image that fills the full window, |
186 |
overwriting borders and any other areas, such as the scrollbar. |
187 |
|
188 |
Specifying this flag changes the behaviour, so that the image only |
189 |
replaces the background of the character area. |
190 |
|
191 |
=back |
192 |
|
193 |
=cut |
194 |
|
195 |
our $HOME; |
196 |
our ($self, $old, $new); |
197 |
our ($x, $y, $w, $h); |
198 |
|
199 |
# enforce at least this interval between updates |
200 |
our $MIN_INTERVAL = 1/100; |
201 |
|
202 |
{ |
203 |
package urxvt::bgdsl; # background language |
204 |
|
205 |
=head2 PROVIDERS/GENERATORS |
206 |
|
207 |
These functions provide an image, by loading it from disk, grabbing it |
208 |
from the root screen or by simply generating it. They are used as starting |
209 |
points to get an image you can play with. |
210 |
|
211 |
=over 4 |
212 |
|
213 |
=item load $path |
214 |
|
215 |
Loads the image at the given C<$path>. The image is set to plane tiling |
216 |
mode. |
217 |
|
218 |
Loaded images will be cached for one cycle. |
219 |
|
220 |
=cut |
221 |
|
222 |
sub load($) { |
223 |
my ($path) = @_; |
224 |
|
225 |
$new->{load}{$path} = $old->{load}{$path} || $self->new_img_from_file ($path); |
226 |
} |
227 |
|
228 |
=item root |
229 |
|
230 |
Returns the root window pixmap, that is, hopefully, the background image |
231 |
of your screen. The image is set to extend mode. |
232 |
|
233 |
This function makes your expression root sensitive, that means it will be |
234 |
reevaluated when the bg image changes. |
235 |
|
236 |
=cut |
237 |
|
238 |
sub root() { |
239 |
$new->{rootpmap_sensitive} = 1; |
240 |
die "root op not supported, exg, we need you"; |
241 |
} |
242 |
|
243 |
=item solid $colour |
244 |
|
245 |
=item solid $width, $height, $colour |
246 |
|
247 |
Creates a new image and completely fills it with the given colour. The |
248 |
image is set to tiling mode. |
249 |
|
250 |
If <$width> and C<$height> are omitted, it creates a 1x1 image, which is |
251 |
useful for solid backgrounds or for use in filtering effects. |
252 |
|
253 |
=cut |
254 |
|
255 |
sub solid($$;$) { |
256 |
my $colour = pop; |
257 |
|
258 |
my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] || 1, $_[1] || 1); |
259 |
$img->fill ($colour); |
260 |
$img |
261 |
} |
262 |
|
263 |
=back |
264 |
|
265 |
=head2 VARIABLES |
266 |
|
267 |
The following functions provide variable data such as the terminal |
268 |
window dimensions. Most of them make your expression sensitive to some |
269 |
events, for example using C<TW> (terminal width) means your expression is |
270 |
evaluated again when the terminal is resized. |
271 |
|
272 |
=over 4 |
273 |
|
274 |
=item TX |
275 |
|
276 |
=item TY |
277 |
|
278 |
Return the X and Y coordinates of the terminal window (the terminal |
279 |
window is the full window by default, and the character area only when in |
280 |
border-respect mode). |
281 |
|
282 |
Using these functions make your expression sensitive to window moves. |
283 |
|
284 |
These functions are mainly useful to align images to the root window. |
285 |
|
286 |
Example: load an image and align it so it looks as if anchored to the |
287 |
background. |
288 |
|
289 |
move -TX, -TY, load "mybg.png" |
290 |
|
291 |
=item TW |
292 |
|
293 |
Return the width (C<TW>) and height (C<TH>) of the terminal window (the |
294 |
terminal window is the full window by default, and the character area only |
295 |
when in border-respect mode). |
296 |
|
297 |
Using these functions make your expression sensitive to window resizes. |
298 |
|
299 |
These functions are mainly useful to scale images, or to clip images to |
300 |
the window size to conserve memory. |
301 |
|
302 |
Example: take the screen background, clip it to the window size, blur it a |
303 |
bit, align it to the window position and use it as background. |
304 |
|
305 |
clip move -TX, -TY, blur 5, root |
306 |
|
307 |
=cut |
308 |
|
309 |
sub TX() { $new->{position_sensitive} = 1; $x } |
310 |
sub TY() { $new->{position_sensitive} = 1; $y } |
311 |
sub TW() { $new->{size_sensitive} = 1; $w } |
312 |
sub TH() { $new->{size_sensitive} = 1; $h } |
313 |
|
314 |
=item now |
315 |
|
316 |
Returns the current time as (fractional) seconds since the epoch. |
317 |
|
318 |
Using this expression does I<not> make your expression sensitive to time, |
319 |
but the next two functions do. |
320 |
|
321 |
=item again $seconds |
322 |
|
323 |
When this function is used the expression will be reevaluated again in |
324 |
C<$seconds> seconds. |
325 |
|
326 |
Example: load some image and rotate it according to the time of day (as if it were |
327 |
the hour pointer of a clock). Update this image every minute. |
328 |
|
329 |
again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png" |
330 |
|
331 |
=item counter $seconds |
332 |
|
333 |
Like C<again>, but also returns an increasing counter value, starting at |
334 |
0, which might be useful for some simple animation effects. |
335 |
|
336 |
=cut |
337 |
|
338 |
sub now() { urxvt::NOW } |
339 |
|
340 |
sub again($) { |
341 |
$new->{again} = $_[0]; |
342 |
} |
343 |
|
344 |
sub counter($) { |
345 |
$new->{again} = $_[0]; |
346 |
$self->{counter} + 0 |
347 |
} |
348 |
|
349 |
=back |
350 |
|
351 |
=head2 TILING MODES |
352 |
|
353 |
The following operators modify the tiling mode of an image, that is, the |
354 |
way that pixels outside the image area are painted when the image is used. |
355 |
|
356 |
=over 4 |
357 |
|
358 |
=item tile $img |
359 |
|
360 |
Tiles the whole plane with the image and returns this new image - or in |
361 |
other words, it returns a copy of the image in plane tiling mode. |
362 |
|
363 |
Example: load an image and tile it over the background, without |
364 |
resizing. The C<tile> call is superfluous because C<load> already defaults |
365 |
to tiling mode. |
366 |
|
367 |
tile load "mybg.png" |
368 |
|
369 |
=item mirror $img |
370 |
|
371 |
Similar to tile, but reflects the image each time it uses a new copy, so |
372 |
that top edges always touch top edges, right edges always touch right |
373 |
edges and so on (with normal tiling, left edges always touch right edges |
374 |
and top always touch bottom edges). |
375 |
|
376 |
Example: load an image and mirror it over the background, avoiding sharp |
377 |
edges at the image borders at the expense of mirroring the image itself |
378 |
|
379 |
mirror load "mybg.png" |
380 |
|
381 |
=item pad $img |
382 |
|
383 |
Takes an image and modifies it so that all pixels outside the image area |
384 |
become transparent. This mode is most useful when you want to place an |
385 |
image over another image or the background colour while leaving all |
386 |
background pixels outside the image unchanged. |
387 |
|
388 |
Example: load an image and display it in the upper left corner. The rest |
389 |
of the space is left "empty" (transparent or wahtever your compisotr does |
390 |
in alpha mode, else background colour). |
391 |
|
392 |
pad load "mybg.png" |
393 |
|
394 |
=item extend $img |
395 |
|
396 |
Extends the image over the whole plane, using the closest pixel in the |
397 |
area outside the image. This mode is mostly useful when you more complex |
398 |
filtering operations and want the pixels outside the image to have the |
399 |
same values as the pixels near the edge. |
400 |
|
401 |
Example: just for curiosity, how does this pixel extension stuff work? |
402 |
|
403 |
extend move 50, 50, load "mybg.png" |
404 |
|
405 |
=cut |
406 |
|
407 |
sub pad($) { |
408 |
my $img = $_[0]->clone; |
409 |
$img->repeat_mode (urxvt::RepeatNone); |
410 |
$img |
411 |
} |
412 |
|
413 |
sub tile($) { |
414 |
my $img = $_[0]->clone; |
415 |
$img->repeat_mode (urxvt::RepeatNormal); |
416 |
$img |
417 |
} |
418 |
|
419 |
sub mirror($) { |
420 |
my $img = $_[0]->clone; |
421 |
$img->repeat_mode (urxvt::RepeatReflect); |
422 |
$img |
423 |
} |
424 |
|
425 |
sub extend($) { |
426 |
my $img = $_[0]->clone; |
427 |
$img->repeat_mode (urxvt::RepeatPad); |
428 |
$img |
429 |
} |
430 |
|
431 |
=back |
432 |
|
433 |
=head2 PIXEL OPERATORS |
434 |
|
435 |
The following operators modify the image pixels in various ways. |
436 |
|
437 |
=over 4 |
438 |
|
439 |
=item clone $img |
440 |
|
441 |
Returns an exact copy of the image. |
442 |
|
443 |
=cut |
444 |
|
445 |
sub clone($) { |
446 |
$_[0]->clone |
447 |
} |
448 |
|
449 |
=item clip $img |
450 |
|
451 |
=item clip $width, $height, $img |
452 |
|
453 |
=item clip $x, $y, $width, $height, $img |
454 |
|
455 |
Clips an image to the given rectangle. If the rectangle is outside the |
456 |
image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is |
457 |
larger than the image, then the tiling mode defines how the extra pixels |
458 |
will be filled. |
459 |
|
460 |
If C<$x> an C<$y> are missing, then C<0> is assumed for both. |
461 |
|
462 |
If C<$width> and C<$height> are missing, then the window size will be |
463 |
assumed. |
464 |
|
465 |
Example: load an image, blur it, and clip it to the window size to save |
466 |
memory. |
467 |
|
468 |
clip blur 10, load "mybg.png" |
469 |
|
470 |
=cut |
471 |
|
472 |
sub clip($;$$;$$) { |
473 |
my $img = pop; |
474 |
my $h = pop || TH; |
475 |
my $w = pop || TW; |
476 |
$img->sub_rect ($_[0], $_[1], $w, $h) |
477 |
} |
478 |
|
479 |
=item scale $img |
480 |
|
481 |
=item scale $size_percent, $img |
482 |
|
483 |
=item scale $width_percent, $height_percent, $img |
484 |
|
485 |
Scales the image by the given percentages in horizontal |
486 |
(C<$width_percent>) and vertical (C<$height_percent>) direction. |
487 |
|
488 |
If only one percentage is give, it is used for both directions. |
489 |
|
490 |
If no percentages are given, scales the image to the window size without |
491 |
keeping aspect. |
492 |
|
493 |
=item resize $width, $height, $img |
494 |
|
495 |
Resizes the image to exactly C<$width> times C<$height> pixels. |
496 |
|
497 |
=cut |
498 |
|
499 |
#TODO: maximise, maximise_fill? |
500 |
|
501 |
sub scale($;$;$) { |
502 |
my $img = pop; |
503 |
|
504 |
@_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01) |
505 |
: @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01) |
506 |
: $img->scale (TW, TH) |
507 |
} |
508 |
|
509 |
sub resize($$$) { |
510 |
my $img = pop; |
511 |
$img->scale ($_[0], $_[1]) |
512 |
} |
513 |
|
514 |
=item move $dx, $dy, $img |
515 |
|
516 |
Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in |
517 |
the vertical. |
518 |
|
519 |
Example: move the image right by 20 pixels and down by 30. |
520 |
|
521 |
move 20, 30, ... |
522 |
|
523 |
=item rootalign $img |
524 |
|
525 |
Moves the image so that it appears glued to the screen as opposed to the |
526 |
window. This gives the illusion of a larger area behind the window. It is |
527 |
exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the |
528 |
top left of the screen. |
529 |
|
530 |
Example: load a background image, put it in mirror mode and root align it. |
531 |
|
532 |
rootalign mirror load "mybg.png" |
533 |
|
534 |
Example: take the screen background and align it, giving the illusion of |
535 |
transparency as long as the window isn't in front of other windows. |
536 |
|
537 |
rootalign root |
538 |
|
539 |
=cut |
540 |
|
541 |
sub move($$;$) { |
542 |
my $img = pop->clone; |
543 |
$img->move ($_[0], $_[1]); |
544 |
$img |
545 |
} |
546 |
|
547 |
sub rootalign($) { |
548 |
move -TX, -TY, $_[0] |
549 |
} |
550 |
|
551 |
=item contrast $factor, $img |
552 |
|
553 |
=item contrast $r, $g, $b, $img |
554 |
|
555 |
=item contrast $r, $g, $b, $a, $img |
556 |
|
557 |
Adjusts the I<contrast> of an image. |
558 |
|
559 |
#TODO# |
560 |
|
561 |
=item brightness $factor, $img |
562 |
|
563 |
=item brightness $r, $g, $b, $img |
564 |
|
565 |
=item brightness $r, $g, $b, $a, $img |
566 |
|
567 |
Adjusts the brightness of an image. |
568 |
|
569 |
=cut |
570 |
|
571 |
sub contrast($$;$$;$) { |
572 |
my $img = pop; |
573 |
my ($r, $g, $b, $a) = @_; |
574 |
|
575 |
($g, $b) = ($r, $r) if @_ < 4; |
576 |
$a = 1 if @_ < 5; |
577 |
|
578 |
$img = $img->clone; |
579 |
$img->contrast ($r, $g, $b, $a); |
580 |
$img |
581 |
} |
582 |
|
583 |
sub brightness($$;$$;$) { |
584 |
my $img = pop; |
585 |
my ($r, $g, $b, $a) = @_; |
586 |
|
587 |
($g, $b) = ($r, $r) if @_ < 4; |
588 |
$a = 1 if @_ < 5; |
589 |
|
590 |
$img = $img->clone; |
591 |
$img->brightness ($r, $g, $b, $a); |
592 |
$img |
593 |
} |
594 |
|
595 |
=item blur $radius, $img |
596 |
|
597 |
=item blur $radius_horz, $radius_vert, $img |
598 |
|
599 |
Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii |
600 |
can also be specified separately. |
601 |
|
602 |
Blurring is often I<very> slow, at least compared or other |
603 |
operators. Larger blur radii are slower than smaller ones, too, so if you |
604 |
don't want to freeze your screen for long times, start experimenting with |
605 |
low values for radius (<5). |
606 |
|
607 |
=cut |
608 |
|
609 |
sub blur($$;$) { |
610 |
my $img = pop; |
611 |
$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0]) |
612 |
} |
613 |
|
614 |
=item rotate $new_width, $new_height, $center_x, $center_y, $degrees |
615 |
|
616 |
Rotates the image by C<$degrees> degrees, counter-clockwise, around the |
617 |
pointer at C<$center_x> and C<$center_y> (specified as percentage of image |
618 |
width/height), generating a new image with width C<$new_width> and height |
619 |
C<$new_height>. |
620 |
|
621 |
#TODO# new width, height, maybe more operators? |
622 |
|
623 |
Example: rotate the image by 90 degrees |
624 |
|
625 |
=cut |
626 |
|
627 |
sub rotate($$$$$$) { |
628 |
my $img = pop; |
629 |
$img->rotate ( |
630 |
$_[0], |
631 |
$_[1], |
632 |
$_[2] * $img->w * .01, |
633 |
$_[3] * $img->h * .01, |
634 |
$_[4] * (3.14159265 / 180), |
635 |
) |
636 |
} |
637 |
|
638 |
=back |
639 |
|
640 |
=cut |
641 |
|
642 |
} |
643 |
|
644 |
sub parse_expr { |
645 |
my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}"; |
646 |
die if $@; |
647 |
$expr |
648 |
} |
649 |
|
650 |
# compiles a parsed expression |
651 |
sub set_expr { |
652 |
my ($self, $expr) = @_; |
653 |
|
654 |
$self->{expr} = $expr; |
655 |
$self->recalculate; |
656 |
} |
657 |
|
658 |
# evaluate the current bg expression |
659 |
sub recalculate { |
660 |
my ($arg_self) = @_; |
661 |
|
662 |
# rate limit evaluation |
663 |
|
664 |
if ($arg_self->{next_refresh} > urxvt::NOW) { |
665 |
$arg_self->{next_refresh_timer} = urxvt::timer->new->after ($arg_self->{next_refresh} - urxvt::NOW)->cb (sub { |
666 |
$arg_self->recalculate; |
667 |
}); |
668 |
return; |
669 |
} |
670 |
|
671 |
$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL; |
672 |
|
673 |
# set environment to evaluate user expression |
674 |
|
675 |
local $self = $arg_self; |
676 |
|
677 |
local $HOME = $ENV{HOME}; |
678 |
local $old = $self->{state}; |
679 |
local $new = my $state = $self->{state} = {}; |
680 |
|
681 |
($x, $y, $w, $h) = |
682 |
$self->background_geometry ($self->{border}); |
683 |
|
684 |
# evaluate user expression |
685 |
|
686 |
my $img = eval { $self->{expr}->() }; |
687 |
warn $@ if $@;#d# |
688 |
die if !UNIVERSAL::isa $img, "urxvt::img"; |
689 |
|
690 |
$state->{size_sensitive} = 1 |
691 |
if $img->repeat_mode != urxvt::RepeatNormal; |
692 |
|
693 |
# if the expression is sensitive to external events, prepare reevaluation then |
694 |
|
695 |
my $repeat; |
696 |
|
697 |
if (my $again = $state->{again}) { |
698 |
$repeat = 1; |
699 |
my $self = $self; |
700 |
$state->{timer} = $again == $old->{again} |
701 |
? $old->{timer} |
702 |
: urxvt::timer->new->after ($again)->interval ($again)->cb (sub { |
703 |
++$self->{counter}; |
704 |
$self->recalculate |
705 |
}); |
706 |
} |
707 |
|
708 |
if (delete $state->{position_sensitive}) { |
709 |
$repeat = 1; |
710 |
$self->enable (position_change => sub { $_[0]->recalculate }); |
711 |
} else { |
712 |
$self->disable ("position_change"); |
713 |
} |
714 |
|
715 |
if (delete $state->{size_sensitive}) { |
716 |
$repeat = 1; |
717 |
$self->enable (size_change => sub { $_[0]->recalculate }); |
718 |
} else { |
719 |
$self->disable ("size_change"); |
720 |
} |
721 |
|
722 |
if (delete $state->{rootpmap_sensitive}) { |
723 |
$repeat = 1; |
724 |
$self->enable (rootpmap_change => sub { $_[0]->recalculate }); |
725 |
} else { |
726 |
$self->disable ("rootpmap_change"); |
727 |
} |
728 |
|
729 |
# clear stuff we no longer need |
730 |
|
731 |
%$old = (); |
732 |
|
733 |
unless ($repeat) { |
734 |
delete $self->{state}; |
735 |
delete $self->{expr}; |
736 |
} |
737 |
|
738 |
# set background pixmap |
739 |
|
740 |
$self->set_background ($img, $self->{border}); |
741 |
$self->scr_recolour (0); |
742 |
$self->want_refresh; |
743 |
} |
744 |
|
745 |
sub on_start { |
746 |
my ($self) = @_; |
747 |
|
748 |
my $expr = $self->x_resource ("background.expr") |
749 |
or return; |
750 |
|
751 |
$self->set_expr (parse_expr $expr); |
752 |
$self->{border} = $self->x_resource_boolean ("background.border"); |
753 |
|
754 |
() |
755 |
} |
756 |
|