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Revision 1.29 by root, Thu Jun 7 13:12:08 2012 UTC vs.
Revision 1.36 by root, Fri Jun 8 20:23:09 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
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
17This extension manages the terminal background by creating a picture that
18is behind the text, replacing the normal background colour.
19
20It does so by evaluating a Perl expression that I<calculates> the image on
21the fly, for example, by grabbing the root background or loading a file.
22
23While the full power of Perl is available, the operators have been design
24to be as simple as possible.
25
26For example, to load an image and scale it to the window size, you would
27use:
28
29 urxvt --background-expr 'scale load "/path/to/mybg.png"'
30
31Or specified as a X resource:
32
33 URxvt.background-expr: scale load "/path/to/mybg.png"
34
35=head2 THEORY OF OPERATION
36
37At startup, just before the window is mapped for the first time, the
38expression is evaluated and must yield an image. The image is then
39extended as necessary to cover the whole terminal window, and is set as a
40background pixmap.
41
42If the image contains an alpha channel, then it will be used as-is in
43visuals that support alpha channels (for example, for a compositing
44manager). In other visuals, the terminal background colour will be used to
45replace any transparency.
46
47When the expression relies, directly or indirectly, on the window size,
48position, the root pixmap, or a timer, then it will be remembered. If not,
49then it will be removed.
50
51If any of the parameters that the expression relies on changes (when the
52window is moved or resized, its position or size changes; when the root
53pixmap is replaced by another one the root background changes; or when the
54timer elapses), then the expression will be evaluated again.
55
56For example, an expression such as C<scale load "$HOME/mybg.png"> scales the
57image to the window size, so it relies on the window size and will
58be reevaluated each time it is changed, but not when it moves for
59example. That ensures that the picture always fills the terminal, even
60after it's size changes.
61
62=head3 EXPRESSIONS
63
64Expressions are normal Perl expressions, in fact, they are Perl blocks -
65which means you could use multiple lines and statements:
66
67 again 3600;
68 if (localtime now)[6]) {
69 return scale load "$HOME/weekday.png";
70 } else {
71 return scale load "$HOME/sunday.png";
72 }
73
74This expression gets evaluated once per hour. It will set F<sunday.png> as
75background on sundays, and F<weekday.png> on all other days.
76
77Fortunately, we expect that most expressions will be much simpler, with
78little Perl knowledge needed.
79
80Basically, you always start with a function that "generates" an image
81object, such as C<load>, which loads an image from disk, or C<root>, which
82returns the root window background image:
83
84 load "$HOME/mypic.png"
85
86The path is usually specified as a quoted string (the exact rules can be
87found in the L<perlop> manpage). The F<$HOME> at the beginning of the
88string is expanded to the home directory.
89
90Then you prepend one or more modifiers or filtering expressions, such as
91C<scale>:
92
93 scale load "$HOME/mypic.png"
94
95Just like a mathematical expression with functions, you should read these
96expressions from right to left, as the C<load> is evaluated first, and
97its result becomes the argument to the C<scale> function.
98
99Many operators also allow some parameters preceding the input image
100that modify its behaviour. For example, C<scale> without any additional
101arguments scales the image to size of the terminal window. If you specify
102an additional argument, it uses it as a percentage:
103
104 scale 200, load "$HOME/mypic.png"
105
106This enlarges the image by a factor of 2 (200%). As you can see, C<scale>
107has now two arguments, the C<200> and the C<load> expression, while
108C<load> only has one argument. Arguments are separated from each other by
109commas.
110
111Scale also accepts two arguments, which are then separate factors for both
112horizontal and vertical dimensions. For example, this halves the image
113width and doubles the image height:
114
115 scale 50, 200, load "$HOME/mypic.png"
116
117TODO
118
119=head3 CYCLES AND CACHING
120
121TODO
122
123Each time the expression is reevaluated, a new cycle is said to have begun. Many operators
124cache their results till the next cycle. For example
125
126=head2 REFERENCE
127
128=head3 COMMAND LINE SWITCHES
129
130=over 4
131
132=item --background-expr perl-expression
133
134Specifies the Perl expression to evaluate.
135
136=item --background-border
137
138By default, the expression creates an image that fills the full window,
139overwriting borders and any other areas, such as the scrollbar.
140
141Specifying this flag changes the behaviour, so that the image only
142replaces the background of the character area.
143
144=back
145
146=cut
147
7our $EXPR; 148our $EXPR;#d#
8#$EXPR = 'move W * 0.1, -H * 0.1, resize W * 0.5, H * 0.5, repeat_none load "opensource.png"'; 149#$EXPR = 'move W * 0.1, -H * 0.1, resize W * 0.5, H * 0.5, repeat_none load "opensource.png"';
9$EXPR = 'move -X, -Y, load "argb.png"'; 150$EXPR = 'move -TX, -TY, load "argb.png"';
10#$EXPR = ' 151#$EXPR = '
11# rotate W, H, 50, 50, counter 1/59.95, repeat_mirror, 152# rotate W, H, 50, 50, counter 1/59.95, repeat_mirror,
12# clip X, Y, W, H, repeat_mirror, 153# clip X, Y, W, H, repeat_mirror,
13# load "/root/pix/das_fette_schwein.jpg" 154# load "/root/pix/das_fette_schwein.jpg"
14#'; 155#';
15#$EXPR = 'solid "red"'; 156#$EXPR = 'solid "red"';
16#$EXPR = 'blur root, 10, 10' 157#$EXPR = 'blur root, 10, 10'
17#$EXPR = 'blur move (root, -x, -y), 5, 5' 158#$EXPR = 'blur move (root, -x, -y), 5, 5'
18#resize load "/root/pix/das_fette_schwein.jpg", w, h 159#resize load "/root/pix/das_fette_schwein.jpg", w, h
19 160
20use Safe; 161our $HOME;
21
22our ($bgdsl_self, $old, $new); 162our ($self, $old, $new);
23our ($x, $y, $w, $h); 163our ($x, $y, $w, $h);
24 164
25# enforce at least this interval between updates 165# enforce at least this interval between updates
26our $MIN_INTERVAL = 1/100; 166our $MIN_INTERVAL = 1/100;
27 167
28{ 168{
29 package urxvt::bgdsl; # background language 169 package urxvt::bgdsl; # background language
30 170
31=head2 PROVIDERS/GENERATORS 171=head2 PROVIDERS/GENERATORS
32 172
173These functions provide an image, by loading it from disk, grabbing it
174from the root screen or by simply generating it. They are used as starting
175points to get an image you can play with.
176
33=over 4 177=over 4
34 178
35=item load $path 179=item load $path
36 180
37Loads the image at the given C<$path>. The image is set to plane tiling 181Loads the image at the given C<$path>. The image is set to plane tiling
38mode. 182mode.
39 183
40 184Loaded images will be cached for one cycle.
41 185
42=cut 186=cut
43 187
44 sub load($) { 188 sub load($) {
45 my ($path) = @_; 189 my ($path) = @_;
46 190
47 $new->{load}{$path} = $old->{load}{$path} || $bgdsl_self->new_img_from_file ($path); 191 $new->{load}{$path} = $old->{load}{$path} || $self->new_img_from_file ($path);
48 } 192 }
193
194=item root
195
196Returns the root window pixmap, that is, hopefully, the background image
197of your screen. The image is set to extend mode.
198
199This function makes your expression root sensitive, that means it will be
200reevaluated when the bg image changes.
201
202=cut
49 203
50 sub root() { 204 sub root() {
51 $new->{rootpmap_sensitive} = 1; 205 $new->{rootpmap_sensitive} = 1;
52 die "root op not supported, exg, we need you"; 206 die "root op not supported, exg, we need you";
53 } 207 }
54 208
209=item solid $colour
210
211=item solid $width, $height, $colour
212
213Creates a new image and completely fills it with the given colour. The
214image is set to tiling mode.
215
216If <$width> and C<$height> are omitted, it creates a 1x1 image, which is
217useful for solid backgrounds or for use in filtering effects.
218
219=cut
220
55 sub solid($;$$) { 221 sub solid($$;$) {
222 my $colour = pop;
223
56 my $img = $bgdsl_self->new_img (urxvt::PictStandardARGB32, $_[1] || 1, $_[2] || 1); 224 my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] || 1, $_[1] || 1);
57 $img->fill ($_[0]); 225 $img->fill ($colour);
58 $img 226 $img
59 } 227 }
60 228
61=back 229=back
62 230
63=head2 VARIABLES 231=head2 VARIABLES
64 232
233The following functions provide variable data such as the terminal
234window dimensions. Most of them make your expression sensitive to some
235events, for example using C<TW> (terminal width) means your expression is
236evaluated again when the terminal is resized.
237
65=over 4 238=over 4
66 239
67=cut 240=item TX
68 241
242=item TY
243
244Return the X and Y coordinates of the terminal window (the terminal
245window is the full window by default, and the character area only when in
246border-respect mode).
247
248Using these functions make your expression sensitive to window moves.
249
250These functions are mainly useful to align images to the root window.
251
252Example: load an image and align it so it looks as if anchored to the
253background.
254
255 move -TX, -TY, load "mybg.png"
256
257=item TW
258
259Return the width (C<TW>) and height (C<TH>) of the terminal window (the
260terminal window is the full window by default, and the character area only
261when in border-respect mode).
262
263Using these functions make your expression sensitive to window resizes.
264
265These functions are mainly useful to scale images, or to clip images to
266the window size to conserve memory.
267
268Example: take the screen background, clip it to the window size, blur it a
269bit, align it to the window position and use it as background.
270
271 clip move -TX, -TY, blur 5, root
272
273=cut
274
69 sub X() { $new->{position_sensitive} = 1; $x } 275 sub TX() { $new->{position_sensitive} = 1; $x }
70 sub Y() { $new->{position_sensitive} = 1; $y } 276 sub TY() { $new->{position_sensitive} = 1; $y }
71 sub W() { $new->{size_sensitive} = 1; $w } 277 sub TW() { $new->{size_sensitive} = 1; $w }
72 sub H() { $new->{size_sensitive} = 1; $h } 278 sub TH() { $new->{size_sensitive} = 1; $h }
279
280=item now
281
282Returns the current time as (fractional) seconds since the epoch.
283
284Using this expression does I<not> make your expression sensitive to time,
285but the next two functions do.
286
287=item again $seconds
288
289When this function is used the expression will be reevaluated again in
290C<$seconds> seconds.
291
292Example: load some image and rotate it according to the time of day (as if it were
293the hour pointer of a clock). Update this image every minute.
294
295 again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
296
297=item counter $seconds
298
299Like C<again>, but also returns an increasing counter value, starting at
3000, which might be useful for some simple animation effects.
301
302=cut
73 303
74 sub now() { urxvt::NOW } 304 sub now() { urxvt::NOW }
75 305
76 sub again($) { 306 sub again($) {
77 $new->{again} = $_[0]; 307 $new->{again} = $_[0];
78 } 308 }
79 309
80 sub counter($) { 310 sub counter($) {
81 $new->{again} = $_[0]; 311 $new->{again} = $_[0];
82 $bgdsl_self->{counter} + 0 312 $self->{counter} + 0
83 } 313 }
84 314
85=back 315=back
86 316
87=head2 TILING MODES 317=head2 TILING MODES
93 323
94=item tile $img 324=item tile $img
95 325
96Tiles the whole plane with the image and returns this new image - or in 326Tiles the whole plane with the image and returns this new image - or in
97other words, it returns a copy of the image in plane tiling mode. 327other words, it returns a copy of the image in plane tiling mode.
328
329Example: load an image and tile it over the background, without
330resizing. The C<tile> call is superfluous because C<load> already defaults
331to tiling mode.
332
333 tile load "mybg.png"
98 334
99=item mirror $img 335=item mirror $img
100 336
101Similar to tile, but reflects the image each time it uses a new copy, so 337Similar to tile, but reflects the image each time it uses a new copy, so
102that top edges always touch top edges, right edges always touch right 338that top edges always touch top edges, right edges always touch right
103edges and so on (with normal tiling, left edges always touch right edges 339edges and so on (with normal tiling, left edges always touch right edges
104and top always touch bottom edges). 340and top always touch bottom edges).
105 341
342Example: load an image and mirror it over the background, avoiding sharp
343edges at the image borders at the expense of mirroring the image itself
344
345 mirror load "mybg.png"
346
106=item pad $img 347=item pad $img
107 348
108Takes an image and modifies it so that all pixels outside the image area 349Takes an image and modifies it so that all pixels outside the image area
109become transparent. This mode is most useful when you want to place an 350become transparent. This mode is most useful when you want to place an
110image over another image or the background colour while leaving all 351image over another image or the background colour while leaving all
111background pixels outside the image unchanged. 352background pixels outside the image unchanged.
112 353
354Example: load an image and display it in the upper left corner. The rest
355of the space is left "empty" (transparent or wahtever your compisotr does
356in alpha mode, else background colour).
357
358 pad load "mybg.png"
359
113=item extend $img 360=item extend $img
114 361
115Extends the image over the whole plane, using the closest pixel in the 362Extends the image over the whole plane, using the closest pixel in the
116area outside the image. This mode is mostly useful when you more complex 363area outside the image. This mode is mostly useful when you more complex
117filtering operations and want the pixels outside the image to have the 364filtering operations and want the pixels outside the image to have the
118same values as the pixels near the edge. 365same values as the pixels near the edge.
119 366
367Example: just for curiosity, how does this pixel extension stuff work?
368
369 extend move 50, 50, load "mybg.png"
370
120=cut 371=cut
121 372
122 sub pad($) { 373 sub pad($) {
123 my $img = $_[0]->clone; 374 my $img = $_[0]->clone;
124 $img->repeat_mode (urxvt::RepeatNone); 375 $img->repeat_mode (urxvt::RepeatNone);
184 435
185=cut 436=cut
186 437
187 sub clip($;$$;$$) { 438 sub clip($;$$;$$) {
188 my $img = pop; 439 my $img = pop;
189 my $h = pop || H; 440 my $h = pop || TH;
190 my $w = pop || W; 441 my $w = pop || TW;
191 $img->sub_rect ($_[0], $_[1], $w, $h) 442 $img->sub_rect ($_[0], $_[1], $w, $h)
192 } 443 }
193 444
194=item scale $img 445=item scale $img
195 446
211 462
212=cut 463=cut
213 464
214#TODO: maximise, maximise_fill? 465#TODO: maximise, maximise_fill?
215 466
216 sub scale($$$) { 467 sub scale($;$;$) {
217 my $img = pop; 468 my $img = pop;
218 469
219 @_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01) 470 @_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01)
220 : @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01) 471 : @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01)
221 : $img->scale (W, H) 472 : $img->scale (TW, TH)
222 } 473 }
223 474
224 sub resize($$$) { 475 sub resize($$$) {
225 my $img = pop; 476 my $img = pop;
226 $img->scale ($_[0], $_[1]) 477 $img->scale ($_[0], $_[1])
227 } 478 }
228 479
229 # TODO: ugly 480=item move $dx, $dy, $img
481
482Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
483the vertical.
484
485Example: move the image right by 20 pixels and down by 30.
486
487 move 20, 30, ...
488
489=item rootalign $img
490
491Moves the image so that it appears glued to the screen as opposed to the
492window. This gives the illusion of a larger area behind the window. It is
493exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
494top left of the screen.
495
496Example: load a background image, put it in mirror mode and root align it.
497
498 rootalign mirror load "mybg.png"
499
500Example: take the screen background and align it, giving the illusion of
501transparency as long as the window isn't in front of other windows.
502
503 rootalign root
504
505=cut
506
230 sub move($$;$) { 507 sub move($$;$) {
231 my $img = pop->clone; 508 my $img = pop->clone;
232 $img->move ($_[0], $_[1]); 509 $img->move ($_[0], $_[1]);
233 $img 510 $img
511 }
512
513 sub rootalign($) {
514 move -TX, -TY, $_[0]
515 }
516
517=item contrast $factor, $img
518
519=item contrast $r, $g, $b, $img
520
521=item contrast $r, $g, $b, $a, $img
522
523Adjusts the I<contrast> of an image.
524
525=item brightness $factor, $img
526
527=item brightness $r, $g, $b, $img
528
529=item brightness $r, $g, $b, $a, $img
530
531=cut
532
533 sub contrast($$;$$;$) {
234# my $img = pop; 534 my $img = pop;
235# $img->sub_rect ( 535 my ($r, $g, $b, $a) = @_;
236# $_[0], $_[1], 536
237# $img->w, $img->h, 537 ($g, $b) = ($r, $r) if @_ < 4;
238# $_[2], 538 $a = 1 if @_ < 5;
239# ) 539
540 $img = $img->clone;
541# $img->contrast ($r, $g, $b, $a);
542 $img
543 }
544
545 sub brightness($$;$$;$) {
546 my $img = pop;
547 my ($r, $g, $b, $a) = @_;
548
549 ($g, $b) = ($r, $r) if @_ < 4;
550 $a = 1 if @_ < 5;
551
552 $img = $img->clone;
553 $img->brightness ($r, $g, $b, $a);
554 $img
555 }
556
557 sub blur($$;$) {
558 my $img = pop;
559 $img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
240 } 560 }
241 561
242 sub rotate($$$$$$) { 562 sub rotate($$$$$$) {
243 my $img = pop; 563 my $img = pop;
244 $img->rotate ( 564 $img->rotate (
248 $_[3] * $img->h * .01, 568 $_[3] * $img->h * .01,
249 $_[4] * (3.14159265 / 180), 569 $_[4] * (3.14159265 / 180),
250 ) 570 )
251 } 571 }
252 572
253 sub blur($$;$) {
254 my $img = pop;
255
256 $img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0]);
257 }
258
259 sub contrast($$;$$;$) {
260 my $img = pop;
261 my ($r, $g, $b, $a) = @_;
262
263 ($g, $b) = ($r, $r) if @_ < 4;
264 $a = 1 if @_ < 5;
265
266 $img = $img->clone;
267 $img->contrast ($r, $g, $b, $a);
268 $img
269 }
270
271 sub brightness($$;$$;$) {
272 my $img = pop;
273 my ($r, $g, $b, $a) = @_;
274
275 ($g, $b) = ($r, $r) if @_ < 4;
276 $a = 1 if @_ < 5;
277
278 $img = $img->clone;
279 $img->brightness ($r, $g, $b, $a);
280 $img
281 }
282
283=back 573=back
284 574
285=cut 575=cut
286 576
287} 577}
300 $self->recalculate; 590 $self->recalculate;
301} 591}
302 592
303# evaluate the current bg expression 593# evaluate the current bg expression
304sub recalculate { 594sub recalculate {
305 my ($self) = @_; 595 my ($arg_self) = @_;
306 596
307 # rate limit evaluation 597 # rate limit evaluation
308 598
309 if ($self->{next_refresh} > urxvt::NOW) { 599 if ($arg_self->{next_refresh} > urxvt::NOW) {
310 $self->{next_refresh_timer} = urxvt::timer->new->after ($self->{next_refresh} - urxvt::NOW)->cb (sub { 600 $arg_self->{next_refresh_timer} = urxvt::timer->new->after ($arg_self->{next_refresh} - urxvt::NOW)->cb (sub {
311 $self->recalculate; 601 $arg_self->recalculate;
312 }); 602 });
313 return; 603 return;
314 } 604 }
315 605
316 $self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL; 606 $arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
317 607
318 # set environment to evaluate user expression 608 # set environment to evaluate user expression
319 609
320 local $bgdsl_self = $self; 610 local $self = $arg_self;
321 611
612 local $HOME = $ENV{HOME};
322 local $old = $self->{state}; 613 local $old = $self->{state};
323 local $new = my $state = $self->{state} = {}; 614 local $new = my $state = $self->{state} = {};
324 615
325 my $border = 0; #d#
326
327 ($x, $y, $w, $h) = 616 ($x, $y, $w, $h) =
328 $self->background_geometry ($border); 617 $self->background_geometry ($self->{border});
329 618
330 # evaluate user expression 619 # evaluate user expression
331 620
332 my $img = eval { $self->{expr}->() }; 621 my $img = eval { $self->{expr}->() };
333 warn $@ if $@;#d# 622 warn $@ if $@;#d#
334 die if !UNIVERSAL::isa $img, "urxvt::img"; 623 die if !UNIVERSAL::isa $img, "urxvt::img";
335 624
625 $state->{size_sensitive} = 1
626 if $img->repeat_mode != urxvt::RepeatNormal;
627
336 # if the expression is sensitive to external events, prepare reevaluation then 628 # if the expression is sensitive to external events, prepare reevaluation then
337 629
338 my $repeat; 630 my $repeat;
339 631
340 if (my $again = $state->{again}) { 632 if (my $again = $state->{again}) {
341 $repeat = 1; 633 $repeat = 1;
634 my $self = $self;
342 $state->{timer} = $again == $old->{again} 635 $state->{timer} = $again == $old->{again}
343 ? $old->{timer} 636 ? $old->{timer}
344 : urxvt::timer->new->after ($again)->interval ($again)->cb (sub { 637 : urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
345 ++$self->{counter}; 638 ++$self->{counter};
346 $self->recalculate 639 $self->recalculate
375 unless ($repeat) { 668 unless ($repeat) {
376 delete $self->{state}; 669 delete $self->{state};
377 delete $self->{expr}; 670 delete $self->{expr};
378 } 671 }
379 672
380 # prepare and set background pixmap 673 # set background pixmap
381 674
382 $img = $img->sub_rect (0, 0, $w, $h)
383 if $img->w != $w || $img->h != $h;
384
385 $self->set_background ($img, $border); 675 $self->set_background ($img, $self->{border});
386 $self->scr_recolour (0); 676 $self->scr_recolour (0);
387 $self->want_refresh; 677 $self->want_refresh;
388} 678}
389 679
390sub on_start { 680sub on_start {
391 my ($self) = @_; 681 my ($self) = @_;
392 682
683 my $expr = $self->x_resource ("background.expr")
684 or return;
685
393 $self->set_expr (parse_expr $EXPR); 686 $self->set_expr (parse_expr $expr);
687 $self->{border} = $self->x_resource_boolean ("background.border");
394 688
395 () 689 ()
396} 690}
397 691

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