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Revision 1.37 by root, Fri Jun 8 20:35:43 2012 UTC vs.
Revision 1.88 by root, Sat May 17 13:38:23 2014 UTC

1#! perl 1#! perl
2 2
3#:META:X_RESOURCE:%.expr:string:background expression 3#:META:RESOURCE:%.expr:string:background expression
4#:META:X_RESOURCE:%.border.:boolean:respect the terminal border 4#:META:RESOURCE:%.border:boolean:respect the terminal border
5#:META:RESOURCE:%.interval:seconds:minimum time between updates
5 6
6#TODO: once, rootalign 7=head1 NAME
7 8
8=head1 background - manage terminal background 9background - manage terminal background
9 10
10=head2 SYNOPSIS 11=head1 SYNOPSIS
11 12
12 urxvt --background-expr 'background expression' 13 urxvt --background-expr 'background expression'
13 --background-border 14 --background-border
15 --background-interval seconds
14 16
17=head1 QUICK AND DIRTY CHEAT SHEET
18
19Just load a random jpeg image and tile the background with it without
20scaling or anything else:
21
22 load "/path/to/img.jpg"
23
24The same, but use mirroring/reflection instead of tiling:
25
26 mirror load "/path/to/img.jpg"
27
28Load an image and scale it to exactly fill the terminal window:
29
30 scale keep { load "/path/to/img.jpg" }
31
32Implement pseudo-transparency by using a suitably-aligned root pixmap
33as window background:
34
35 rootalign root
36
37Likewise, but keep a blurred copy:
38
39 rootalign keep { blur 10, root }
40
15=head2 DESCRIPTION 41=head1 DESCRIPTION
16 42
17This extension manages the terminal background by creating a picture that 43This extension manages the terminal background by creating a picture that
18is behind the text, replacing the normal background colour. 44is behind the text, replacing the normal background colour.
19 45
20It does so by evaluating a Perl expression that I<calculates> the image on 46It does so by evaluating a Perl expression that I<calculates> the image on
24to be as simple as possible. 50to be as simple as possible.
25 51
26For example, to load an image and scale it to the window size, you would 52For example, to load an image and scale it to the window size, you would
27use: 53use:
28 54
29 urxvt --background-expr 'scale load "/path/to/mybg.png"' 55 urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
30 56
31Or specified as a X resource: 57Or specified as a X resource:
32 58
33 URxvt.background-expr: scale load "/path/to/mybg.png" 59 URxvt.background-expr: scale keep { load "/path/to/mybg.png" }
34 60
35=head2 THEORY OF OPERATION 61=head1 THEORY OF OPERATION
36 62
37At startup, just before the window is mapped for the first time, the 63At startup, just before the window is mapped for the first time, the
38expression is evaluated and must yield an image. The image is then 64expression 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 65extended as necessary to cover the whole terminal window, and is set as a
40background pixmap. 66background pixmap.
51If any of the parameters that the expression relies on changes (when the 77If 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 78window 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 79pixmap is replaced by another one the root background changes; or when the
54timer elapses), then the expression will be evaluated again. 80timer elapses), then the expression will be evaluated again.
55 81
56For example, an expression such as C<scale load "$HOME/mybg.png"> scales the 82For example, an expression such as C<scale keep { load "$HOME/mybg.png"
57image to the window size, so it relies on the window size and will 83}> scales the image to the window size, so it relies on the window size
58be reevaluated each time it is changed, but not when it moves for 84and will be reevaluated each time it is changed, but not when it moves for
59example. That ensures that the picture always fills the terminal, even 85example. That ensures that the picture always fills the terminal, even
60after it's size changes. 86after its size changes.
61 87
62=head3 EXPRESSIONS 88=head2 EXPRESSIONS
63 89
64Expressions are normal Perl expressions, in fact, they are Perl blocks - 90Expressions are normal Perl expressions, in fact, they are Perl blocks -
65which means you could use multiple lines and statements: 91which means you could use multiple lines and statements:
66 92
93 scale keep {
67 again 3600; 94 again 3600;
68 if (localtime now)[6]) { 95 if (localtime now)[6]) {
69 return scale load "$HOME/weekday.png"; 96 return load "$HOME/weekday.png";
70 } else { 97 } else {
71 return scale load "$HOME/sunday.png"; 98 return load "$HOME/sunday.png";
99 }
72 } 100 }
73 101
74This expression gets evaluated once per hour. It will set F<sunday.png> as 102This inner expression is evaluated once per hour (and whenever the
103terminal window is resized). It sets F<sunday.png> as background on
75background on sundays, and F<weekday.png> on all other days. 104Sundays, and F<weekday.png> on all other days.
76 105
77Fortunately, we expect that most expressions will be much simpler, with 106Fortunately, we expect that most expressions will be much simpler, with
78little Perl knowledge needed. 107little Perl knowledge needed.
79 108
80Basically, you always start with a function that "generates" an image 109Basically, you always start with a function that "generates" an image
97its result becomes the argument to the C<scale> function. 126its result becomes the argument to the C<scale> function.
98 127
99Many operators also allow some parameters preceding the input image 128Many operators also allow some parameters preceding the input image
100that modify its behaviour. For example, C<scale> without any additional 129that modify its behaviour. For example, C<scale> without any additional
101arguments scales the image to size of the terminal window. If you specify 130arguments scales the image to size of the terminal window. If you specify
102an additional argument, it uses it as a percentage: 131an additional argument, it uses it as a scale factor (multiply by 100 to
132get a percentage):
103 133
104 scale 200, load "$HOME/mypic.png" 134 scale 2, load "$HOME/mypic.png"
105 135
106This enlarges the image by a factor of 2 (200%). As you can see, C<scale> 136This 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 137has 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 138C<load> only has one argument. Arguments are separated from each other by
109commas. 139commas.
110 140
111Scale also accepts two arguments, which are then separate factors for both 141Scale also accepts two arguments, which are then separate factors for both
112horizontal and vertical dimensions. For example, this halves the image 142horizontal and vertical dimensions. For example, this halves the image
113width and doubles the image height: 143width and doubles the image height:
114 144
115 scale 50, 200, load "$HOME/mypic.png" 145 scale 0.5, 2, load "$HOME/mypic.png"
116 146
117TODO 147IF you try out these expressions, you might suffer from some sluggishness,
148because each time the terminal is resized, it loads the PNG image again
149and scales it. Scaling is usually fast (and unavoidable), but loading the
150image can be quite time consuming. This is where C<keep> comes in handy:
118 151
119=head3 CYCLES AND CACHING 152 scale 0.5, 2, keep { load "$HOME/mypic.png" }
120 153
121TODO 154The C<keep> operator executes all the statements inside the braces only
155once, or when it thinks the outcome might change. In other cases it
156returns the last value computed by the brace block.
122 157
123Each time the expression is reevaluated, a new cycle is said to have begun. Many operators 158This means that the C<load> is only executed once, which makes it much
124cache their results till the next cycle. For example 159faster, but also means that more memory is being used, because the loaded
160image must be kept in memory at all times. In this expression, the
161trade-off is likely worth it.
125 162
163But back to effects: Other effects than scaling are also readily
164available, for example, you can tile the image to fill the whole window,
165instead of resizing it:
166
167 tile keep { load "$HOME/mypic.png" }
168
169In fact, images returned by C<load> are in C<tile> mode by default, so the
170C<tile> operator is kind of superfluous.
171
172Another common effect is to mirror the image, so that the same edges
173touch:
174
175 mirror keep { load "$HOME/mypic.png" }
176
177Another common background expression is:
178
179 rootalign root
180
181This one first takes a snapshot of the screen background image, and then
182moves it to the upper left corner of the screen (as opposed to the upper
183left corner of the terminal window)- the result is pseudo-transparency:
184the image seems to be static while the window is moved around.
185
186=head2 COLOUR SPECIFICATIONS
187
188Whenever an operator expects a "colour", then this can be specified in one
189of two ways: Either as string with an X11 colour specification, such as:
190
191 "red" # named colour
192 "#f00" # simple rgb
193 "[50]red" # red with 50% alpha
194 "TekHVC:300/50/50" # anything goes
195
196OR as an array reference with one, three or four components:
197
198 [0.5] # 50% gray, 100% alpha
199 [0.5, 0, 0] # dark red, no green or blur, 100% alpha
200 [0.5, 0, 0, 0.7] # same with explicit 70% alpha
201
202=head2 CACHING AND SENSITIVITY
203
204Since some operations (such as C<load> and C<blur>) can take a long time,
205caching results can be very important for a smooth operation. Caching can
206also be useful to reduce memory usage, though, for example, when an image
207is cached by C<load>, it could be shared by multiple terminal windows
208running inside urxvtd.
209
210=head3 C<keep { ... }> caching
211
212The most important way to cache expensive operations is to use C<keep {
213... }>. The C<keep> operator takes a block of multiple statements enclosed
214by C<{}> and keeps the return value in memory.
215
216An expression can be "sensitive" to various external events, such as
217scaling or moving the window, root background changes and timers. Simply
218using an expression (such as C<scale> without parameters) that depends on
219certain changing values (called "variables"), or using those variables
220directly, will make an expression sensitive to these events - for example,
221using C<scale> or C<TW> will make the expression sensitive to the terminal
222size, and thus to resizing events.
223
224When such an event happens, C<keep> will automatically trigger a
225reevaluation of the whole expression with the new value of the expression.
226
227C<keep> is most useful for expensive operations, such as C<blur>:
228
229 rootalign keep { blur 20, root }
230
231This makes a blurred copy of the root background once, and on subsequent
232calls, just root-aligns it. Since C<blur> is usually quite slow and
233C<rootalign> is quite fast, this trades extra memory (for the cached
234blurred pixmap) with speed (blur only needs to be redone when root
235changes).
236
237=head3 C<load> caching
238
239The C<load> operator itself does not keep images in memory, but as long as
240the image is still in memory, C<load> will use the in-memory image instead
241of loading it freshly from disk.
242
243That means that this expression:
244
245 keep { load "$HOME/path..." }
246
247Not only caches the image in memory, other terminal instances that try to
248C<load> it can reuse that in-memory copy.
249
126=head2 REFERENCE 250=head1 REFERENCE
127 251
128=head3 COMMAND LINE SWITCHES 252=head2 COMMAND LINE SWITCHES
129 253
130=over 4 254=over 4
131 255
132=item --background-expr perl-expression 256=item --background-expr perl-expression
133 257
139overwriting borders and any other areas, such as the scrollbar. 263overwriting borders and any other areas, such as the scrollbar.
140 264
141Specifying this flag changes the behaviour, so that the image only 265Specifying this flag changes the behaviour, so that the image only
142replaces the background of the character area. 266replaces the background of the character area.
143 267
268=item --background-interval seconds
269
270Since some operations in the underlying XRender extension can effectively
271freeze your X-server for prolonged time, this extension enforces a minimum
272time between updates, which is normally about 0.1 seconds.
273
274If you want to do updates more often, you can decrease this safety
275interval with this switch.
276
144=back 277=back
145 278
146=cut 279=cut
147 280
148our $EXPR;#d# 281our %_IMG_CACHE;
149#$EXPR = 'move W * 0.1, -H * 0.1, resize W * 0.5, H * 0.5, repeat_none load "opensource.png"';
150$EXPR = 'move -TX, -TY, load "argb.png"';
151#$EXPR = '
152# rotate W, H, 50, 50, counter 1/59.95, repeat_mirror,
153# clip X, Y, W, H, repeat_mirror,
154# load "/root/pix/das_fette_schwein.jpg"
155#';
156#$EXPR = 'solid "red"';
157#$EXPR = 'blur root, 10, 10'
158#$EXPR = 'blur move (root, -x, -y), 5, 5'
159#resize load "/root/pix/das_fette_schwein.jpg", w, h
160
161our $HOME; 282our $HOME;
162our ($self, $old, $new); 283our ($self, $frame);
163our ($x, $y, $w, $h); 284our ($x, $y, $w, $h, $focus);
164 285
165# enforce at least this interval between updates 286# enforce at least this interval between updates
166our $MIN_INTERVAL = 1/100; 287our $MIN_INTERVAL = 6/59.951;
167 288
168{ 289{
169 package urxvt::bgdsl; # background language 290 package urxvt::bgdsl; # background language
291
292 sub FR_PARENT() { 0 } # parent frame, if any - must be #0
293 sub FR_CACHE () { 1 } # cached values
294 sub FR_AGAIN () { 2 } # what this expr is sensitive to
295 sub FR_STATE () { 3 } # watchers etc.
296
297 use List::Util qw(min max sum shuffle);
170 298
171=head2 PROVIDERS/GENERATORS 299=head2 PROVIDERS/GENERATORS
172 300
173These functions provide an image, by loading it from disk, grabbing it 301These 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 302from the root screen or by simply generating it. They are used as starting
179=item load $path 307=item load $path
180 308
181Loads the image at the given C<$path>. The image is set to plane tiling 309Loads the image at the given C<$path>. The image is set to plane tiling
182mode. 310mode.
183 311
184Loaded images will be cached for one cycle. 312If the image is already in memory (e.g. because another terminal instance
313uses it), then the in-memory copy is returned instead.
185 314
315=item load_uc $path
316
317Load uncached - same as load, but does not cache the image, which means it
318is I<always> loaded from the filesystem again, even if another copy of it
319is in memory at the time.
320
186=cut 321=cut
322
323 sub load_uc($) {
324 $self->new_img_from_file ($_[0])
325 }
187 326
188 sub load($) { 327 sub load($) {
189 my ($path) = @_; 328 my ($path) = @_;
190 329
191 $new->{load}{$path} = $old->{load}{$path} || $self->new_img_from_file ($path); 330 $_IMG_CACHE{$path} || do {
331 my $img = load_uc $path;
332 Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
333 $img
334 }
192 } 335 }
193 336
194=item root 337=item root
195 338
196Returns the root window pixmap, that is, hopefully, the background image 339Returns the root window pixmap, that is, hopefully, the background image
197of your screen. The image is set to extend mode. 340of your screen.
198 341
199This function makes your expression root sensitive, that means it will be 342This function makes your expression root sensitive, that means it will be
200reevaluated when the bg image changes. 343reevaluated when the bg image changes.
201 344
202=cut 345=cut
203 346
204 sub root() { 347 sub root() {
205 $new->{rootpmap_sensitive} = 1; 348 $frame->[FR_AGAIN]{rootpmap} = 1;
206 die "root op not supported, exg, we need you"; 349 $self->new_img_from_root
207 } 350 }
208 351
209=item solid $colour 352=item solid $colour
210 353
211=item solid $width, $height, $colour 354=item solid $width, $height, $colour
212 355
213Creates a new image and completely fills it with the given colour. The 356Creates a new image and completely fills it with the given colour. The
214image is set to tiling mode. 357image is set to tiling mode.
215 358
216If <$width> and C<$height> are omitted, it creates a 1x1 image, which is 359If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
217useful for solid backgrounds or for use in filtering effects. 360useful for solid backgrounds or for use in filtering effects.
218 361
219=cut 362=cut
220 363
221 sub solid($$;$) { 364 sub solid($;$$) {
222 my $colour = pop; 365 my $colour = pop;
223 366
224 my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] || 1, $_[1] || 1); 367 my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] || 1, $_[1] || 1);
225 $img->fill ($colour); 368 $img->fill ($colour);
226 $img 369 $img
227 } 370 }
228 371
229=back 372=item clone $img
230 373
231=head2 VARIABLES 374Returns an exact copy of the image. This is useful if you want to have
375multiple copies of the same image to apply different effects to.
232 376
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
238=over 4
239
240=item TX
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 377=cut
274 378
275 sub TX() { $new->{position_sensitive} = 1; $x }
276 sub TY() { $new->{position_sensitive} = 1; $y }
277 sub TW() { $new->{size_sensitive} = 1; $w }
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 $seconds
298
299Like C<again>, but also returns an increasing counter value, starting at
3000, which might be useful for some simple animation effects.
301
302=cut
303
304 sub now() { urxvt::NOW }
305
306 sub again($) {
307 $new->{again} = $_[0];
308 }
309
310 sub counter($) { 379 sub clone($) {
311 $new->{again} = $_[0]; 380 $_[0]->clone
312 $self->{counter} + 0 381 }
382
383=item merge $img ...
384
385Takes any number of images and merges them together, creating a single
386image containing them all. The tiling mode of the first image is used as
387the tiling mode of the resulting image.
388
389This function is called automatically when an expression returns multiple
390images.
391
392=cut
393
394 sub merge(@) {
395 return $_[0] unless $#_;
396
397 # rather annoyingly clumsy, but optimisation is for another time
398
399 my $x0 = +1e9;
400 my $y0 = +1e9;
401 my $x1 = -1e9;
402 my $y1 = -1e9;
403
404 for (@_) {
405 my ($x, $y, $w, $h) = $_->geometry;
406
407 $x0 = $x if $x0 > $x;
408 $y0 = $y if $y0 > $y;
409
410 $x += $w;
411 $y += $h;
412
413 $x1 = $x if $x1 < $x;
414 $y1 = $y if $y1 < $y;
415 }
416
417 my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
418 $base->repeat_mode ($_[0]->repeat_mode);
419 $base->fill ([0, 0, 0, 0]);
420
421 $base->draw ($_)
422 for @_;
423
424 $base
313 } 425 }
314 426
315=back 427=back
316 428
317=head2 TILING MODES 429=head2 TILING MODES
350become transparent. This mode is most useful when you want to place an 462become transparent. This mode is most useful when you want to place an
351image over another image or the background colour while leaving all 463image over another image or the background colour while leaving all
352background pixels outside the image unchanged. 464background pixels outside the image unchanged.
353 465
354Example: load an image and display it in the upper left corner. The rest 466Example: 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 467of the space is left "empty" (transparent or whatever your compositor does
356in alpha mode, else background colour). 468in alpha mode, else background colour).
357 469
358 pad load "mybg.png" 470 pad load "mybg.png"
359 471
360=item extend $img 472=item extend $img
361 473
362Extends the image over the whole plane, using the closest pixel in the 474Extends the image over the whole plane, using the closest pixel in the
363area outside the image. This mode is mostly useful when you more complex 475area outside the image. This mode is mostly useful when you use more complex
364filtering operations and want the pixels outside the image to have the 476filtering operations and want the pixels outside the image to have the
365same values as the pixels near the edge. 477same values as the pixels near the edge.
366 478
367Example: just for curiosity, how does this pixel extension stuff work? 479Example: just for curiosity, how does this pixel extension stuff work?
368 480
394 $img 506 $img
395 } 507 }
396 508
397=back 509=back
398 510
399=head2 PIXEL OPERATORS 511=head2 VARIABLE VALUES
400 512
401The following operators modify the image pixels in various ways. 513The following functions provide variable data such as the terminal window
514dimensions. They are not (Perl-) variables, they just return stuff that
515varies. Most of them make your expression sensitive to some events, for
516example using C<TW> (terminal width) means your expression is evaluated
517again when the terminal is resized.
402 518
403=over 4 519=over 4
404 520
405=item clone $img 521=item TX
406 522
407Returns an exact copy of the image. 523=item TY
408 524
409=cut 525Return the X and Y coordinates of the terminal window (the terminal
526window is the full window by default, and the character area only when in
527border-respect mode).
410 528
529Using these functions makes your expression sensitive to window moves.
530
531These functions are mainly useful to align images to the root window.
532
533Example: load an image and align it so it looks as if anchored to the
534background (that's exactly what C<rootalign> does btw.):
535
536 move -TX, -TY, keep { load "mybg.png" }
537
538=item TW
539
540=item TH
541
542Return the width (C<TW>) and height (C<TH>) of the terminal window (the
543terminal window is the full window by default, and the character area only
544when in border-respect mode).
545
546Using these functions makes your expression sensitive to window resizes.
547
548These functions are mainly useful to scale images, or to clip images to
549the window size to conserve memory.
550
551Example: take the screen background, clip it to the window size, blur it a
552bit, align it to the window position and use it as background.
553
554 clip move -TX, -TY, keep { blur 5, root }
555
556=item FOCUS
557
558Returns a boolean indicating whether the terminal window has keyboard
559focus, in which case it returns true.
560
561Using this function makes your expression sensitive to focus changes.
562
563A common use case is to fade the background image when the terminal loses
564focus, often together with the C<-fade> command line option. In fact,
565there is a special function for just that use case: C<focus_fade>.
566
567Example: use two entirely different background images, depending on
568whether the window has focus.
569
570 FOCUS ? keep { load "has_focus.jpg" } : keep { load "no_focus.jpg" }
571
572=cut
573
574 sub TX () { $frame->[FR_AGAIN]{position} = 1; $x }
575 sub TY () { $frame->[FR_AGAIN]{position} = 1; $y }
576 sub TW () { $frame->[FR_AGAIN]{size} = 1; $w }
577 sub TH () { $frame->[FR_AGAIN]{size} = 1; $h }
578 sub FOCUS() { $frame->[FR_AGAIN]{focus} = 1; $focus }
579
580=item now
581
582Returns the current time as (fractional) seconds since the epoch.
583
584Using this expression does I<not> make your expression sensitive to time,
585but the next two functions do.
586
587=item again $seconds
588
589When this function is used the expression will be reevaluated again in
590C<$seconds> seconds.
591
592Example: load some image and rotate it according to the time of day (as if it were
593the hour pointer of a clock). Update this image every minute.
594
595 again 60;
596 rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
597
598=item counter $seconds
599
600Like C<again>, but also returns an increasing counter value, starting at
6010, which might be useful for some simple animation effects.
602
603=cut
604
605 sub now() { urxvt::NOW }
606
607 sub again($) {
608 $frame->[FR_AGAIN]{time} = $_[0];
609 }
610
411 sub clone($) { 611 sub counter($) {
412 $_[0]->clone 612 $frame->[FR_AGAIN]{time} = $_[0];
613 $frame->[FR_STATE]{counter} + 0
413 } 614 }
615
616=back
617
618=head2 SHAPE CHANGING OPERATORS
619
620The following operators modify the shape, size or position of the image.
621
622=over 4
414 623
415=item clip $img 624=item clip $img
416 625
417=item clip $width, $height, $img 626=item clip $width, $height, $img
418 627
421Clips an image to the given rectangle. If the rectangle is outside the 630Clips an image to the given rectangle. If the rectangle is outside the
422image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is 631image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is
423larger than the image, then the tiling mode defines how the extra pixels 632larger than the image, then the tiling mode defines how the extra pixels
424will be filled. 633will be filled.
425 634
426If C<$x> an C<$y> are missing, then C<0> is assumed for both. 635If C<$x> and C<$y> are missing, then C<0> is assumed for both.
427 636
428If C<$width> and C<$height> are missing, then the window size will be 637If C<$width> and C<$height> are missing, then the window size will be
429assumed. 638assumed.
430 639
431Example: load an image, blur it, and clip it to the window size to save 640Example: load an image, blur it, and clip it to the window size to save
432memory. 641memory.
433 642
434 clip blur 10, load "mybg.png" 643 clip keep { blur 10, load "mybg.png" }
435 644
436=cut 645=cut
437 646
438 sub clip($;$$;$$) { 647 sub clip($;$$;$$) {
439 my $img = pop; 648 my $img = pop;
442 $img->sub_rect ($_[0], $_[1], $w, $h) 651 $img->sub_rect ($_[0], $_[1], $w, $h)
443 } 652 }
444 653
445=item scale $img 654=item scale $img
446 655
447=item scale $size_percent, $img 656=item scale $size_factor, $img
448 657
449=item scale $width_percent, $height_percent, $img 658=item scale $width_factor, $height_factor, $img
450 659
451Scales the image by the given percentages in horizontal 660Scales the image by the given factors in horizontal
452(C<$width_percent>) and vertical (C<$height_percent>) direction. 661(C<$width>) and vertical (C<$height>) direction.
453 662
454If only one percentage is give, it is used for both directions. 663If only one factor is given, it is used for both directions.
455 664
456If no percentages are given, scales the image to the window size without 665If no factors are given, scales the image to the window size without
457keeping aspect. 666keeping aspect.
458 667
459=item resize $width, $height, $img 668=item resize $width, $height, $img
460 669
461Resizes the image to exactly C<$width> times C<$height> pixels. 670Resizes the image to exactly C<$width> times C<$height> pixels.
462 671
463=cut 672=item fit $img
464 673
465#TODO: maximise, maximise_fill? 674=item fit $width, $height, $img
675
676Fits the image into the given C<$width> and C<$height> without changing
677aspect, or the terminal size. That means it will be shrunk or grown until
678the whole image fits into the given area, possibly leaving borders.
679
680=item cover $img
681
682=item cover $width, $height, $img
683
684Similar to C<fit>, but shrinks or grows until all of the area is covered
685by the image, so instead of potentially leaving borders, it will cut off
686image data that doesn't fit.
687
688=cut
466 689
467 sub scale($;$;$) { 690 sub scale($;$;$) {
468 my $img = pop; 691 my $img = pop;
469 692
470 @_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01) 693 @_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
471 : @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01) 694 : @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
472 : $img->scale (TW, TH) 695 : $img->scale (TW, TH)
473 } 696 }
474 697
475 sub resize($$$) { 698 sub resize($$$) {
476 my $img = pop; 699 my $img = pop;
477 $img->scale ($_[0], $_[1]) 700 $img->scale ($_[0], $_[1])
478 } 701 }
479 702
703 sub fit($;$$) {
704 my $img = pop;
705 my $w = ($_[0] || TW) / $img->w;
706 my $h = ($_[1] || TH) / $img->h;
707 scale +(min $w, $h), $img
708 }
709
710 sub cover($;$$) {
711 my $img = pop;
712 my $w = ($_[0] || TW) / $img->w;
713 my $h = ($_[1] || TH) / $img->h;
714 scale +(max $w, $h), $img
715 }
716
480=item move $dx, $dy, $img 717=item move $dx, $dy, $img
481 718
482Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in 719Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
483the vertical. 720the vertical.
484 721
485Example: move the image right by 20 pixels and down by 30. 722Example: move the image right by 20 pixels and down by 30.
486 723
487 move 20, 30, ... 724 move 20, 30, ...
725
726=item align $xalign, $yalign, $img
727
728Aligns the image according to a factor - C<0> means the image is moved to
729the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
730exactly centered and C<1> means it touches the right or bottom edge.
731
732Example: remove any visible border around an image, center it vertically but move
733it to the right hand side.
734
735 align 1, 0.5, pad $img
736
737=item center $img
738
739=item center $width, $height, $img
740
741Centers the image, i.e. the center of the image is moved to the center of
742the terminal window (or the box specified by C<$width> and C<$height> if
743given).
744
745Example: load an image and center it.
746
747 center keep { pad load "mybg.png" }
488 748
489=item rootalign $img 749=item rootalign $img
490 750
491Moves the image so that it appears glued to the screen as opposed to the 751Moves 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 752window. 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 753exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
494top left of the screen. 754top left of the screen.
495 755
496Example: load a background image, put it in mirror mode and root align it. 756Example: load a background image, put it in mirror mode and root align it.
497 757
498 rootalign mirror load "mybg.png" 758 rootalign keep { mirror load "mybg.png" }
499 759
500Example: take the screen background and align it, giving the illusion of 760Example: take the screen background and align it, giving the illusion of
501transparency as long as the window isn't in front of other windows. 761transparency as long as the window isn't in front of other windows.
502 762
503 rootalign root 763 rootalign root
504 764
505=cut 765=cut
506 766
507 sub move($$;$) { 767 sub move($$;$) {
508 my $img = pop->clone; 768 my $img = pop->clone;
509 $img->move ($_[0], $_[1]); 769 $img->move ($_[0], $_[1]);
510 $img 770 $img
511 } 771 }
512 772
773 sub align($;$$) {
774 my $img = pop;
775
776 move $_[0] * (TW - $img->w),
777 $_[1] * (TH - $img->h),
778 $img
779 }
780
781 sub center($;$$) {
782 my $img = pop;
783 my $w = $_[0] || TW;
784 my $h = $_[1] || TH;
785
786 move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
787 }
788
513 sub rootalign($) { 789 sub rootalign($) {
514 move -TX, -TY, $_[0] 790 move -TX, -TY, $_[0]
515 } 791 }
516 792
793=item rotate $center_x, $center_y, $degrees, $img
794
795Rotates the image clockwise by C<$degrees> degrees, around the point at
796C<$center_x> and C<$center_y> (specified as factor of image width/height).
797
798Example: rotate the image by 90 degrees around its center.
799
800 rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
801
802=cut
803
804 sub rotate($$$$) {
805 my $img = pop;
806 $img->rotate (
807 $_[0] * ($img->w + $img->x),
808 $_[1] * ($img->h + $img->y),
809 $_[2] * (3.14159265 / 180),
810 )
811 }
812
813=back
814
815=head2 COLOUR MODIFICATIONS
816
817The following operators change the pixels of the image.
818
819=over 4
820
821=item tint $color, $img
822
823Tints the image in the given colour.
824
825Example: tint the image red.
826
827 tint "red", load "rgb.png"
828
829Example: the same, but specify the colour by component.
830
831 tint [1, 0, 0], load "rgb.png"
832
833=cut
834
835 sub tint($$) {
836 $_[1]->tint ($_[0])
837 }
838
839=item shade $factor, $img
840
841Shade the image by the given factor.
842
843=cut
844
845 sub shade($$) {
846 $_[1]->shade ($_[0])
847 }
848
517=item contrast $factor, $img 849=item contrast $factor, $img
518 850
519=item contrast $r, $g, $b, $img 851=item contrast $r, $g, $b, $img
520 852
521=item contrast $r, $g, $b, $a, $img 853=item contrast $r, $g, $b, $a, $img
522 854
523Adjusts the I<contrast> of an image. 855Adjusts the I<contrast> of an image.
524 856
857The first form applies a single C<$factor> to red, green and blue, the
858second form applies separate factors to each colour channel, and the last
859form includes the alpha channel.
860
861Values from 0 to 1 lower the contrast, values higher than 1 increase the
862contrast.
863
864Due to limitations in the underlying XRender extension, lowering contrast
865also reduces brightness, while increasing contrast currently also
866increases brightness.
867
525=item brightness $factor, $img 868=item brightness $bias, $img
526 869
527=item brightness $r, $g, $b, $img 870=item brightness $r, $g, $b, $img
528 871
529=item brightness $r, $g, $b, $a, $img 872=item brightness $r, $g, $b, $a, $img
873
874Adjusts the brightness of an image.
875
876The first form applies a single C<$bias> to red, green and blue, the
877second form applies separate biases to each colour channel, and the last
878form includes the alpha channel.
879
880Values less than 0 reduce brightness, while values larger than 0 increase
881it. Useful range is from -1 to 1 - the former results in a black, the
882latter in a white picture.
883
884Due to idiosyncrasies in the underlying XRender extension, biases less
885than zero can be I<very> slow.
886
887You can also try the experimental(!) C<muladd> operator.
530 888
531=cut 889=cut
532 890
533 sub contrast($$;$$;$) { 891 sub contrast($$;$$;$) {
534 my $img = pop; 892 my $img = pop;
535 my ($r, $g, $b, $a) = @_; 893 my ($r, $g, $b, $a) = @_;
536 894
537 ($g, $b) = ($r, $r) if @_ < 4; 895 ($g, $b) = ($r, $r) if @_ < 3;
538 $a = 1 if @_ < 5; 896 $a = 1 if @_ < 4;
539 897
540 $img = $img->clone; 898 $img = $img->clone;
541 $img->contrast ($r, $g, $b, $a); 899 $img->contrast ($r, $g, $b, $a);
542 $img 900 $img
543 } 901 }
544 902
545 sub brightness($$;$$;$) { 903 sub brightness($$;$$;$) {
546 my $img = pop; 904 my $img = pop;
547 my ($r, $g, $b, $a) = @_; 905 my ($r, $g, $b, $a) = @_;
548 906
549 ($g, $b) = ($r, $r) if @_ < 4; 907 ($g, $b) = ($r, $r) if @_ < 3;
550 $a = 1 if @_ < 5; 908 $a = 1 if @_ < 4;
551 909
552 $img = $img->clone; 910 $img = $img->clone;
553 $img->brightness ($r, $g, $b, $a); 911 $img->brightness ($r, $g, $b, $a);
554 $img 912 $img
555 } 913 }
556 914
915=item muladd $mul, $add, $img # EXPERIMENTAL
916
917First multiplies the pixels by C<$mul>, then adds C<$add>. This can be used
918to implement brightness and contrast at the same time, with a wider value
919range than contrast and brightness operators.
920
921Due to numerous bugs in XRender implementations, it can also introduce a
922number of visual artifacts.
923
924Example: increase contrast by a factor of C<$c> without changing image
925brightness too much.
926
927 muladd $c, (1 - $c) * 0.5, $img
928
929=cut
930
931 sub muladd($$$) {
932 $_[2]->muladd ($_[0], $_[1])
933 }
934
935=item blur $radius, $img
936
937=item blur $radius_horz, $radius_vert, $img
938
939Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
940can also be specified separately.
941
942Blurring is often I<very> slow, at least compared or other
943operators. Larger blur radii are slower than smaller ones, too, so if you
944don't want to freeze your screen for long times, start experimenting with
945low values for radius (<5).
946
947=cut
948
557 sub blur($$;$) { 949 sub blur($$;$) {
558 my $img = pop; 950 my $img = pop;
559 $img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0]) 951 $img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
560 } 952 }
561 953
562 sub rotate($$$$$$) { 954=item focus_fade $img
955
956=item focus_fade $factor, $img
957
958=item focus_fade $factor, $color, $img
959
960Fades the image by the given factor (and colour) when focus is lost (the
961same as the C<-fade>/C<-fadecolor> command line options, which also supply
962the default values for C<factor> and C<$color>. Unlike with C<-fade>, the
963C<$factor> is a real value, not a percentage value (that is, 0..1, not
9640..100).
965
966Example: do the right thing when focus fading is requested.
967
968 focus_fade load "mybg.jpg";
969
970=cut
971
972 sub focus_fade($;$$) {
563 my $img = pop; 973 my $img = pop;
564 $img->rotate ( 974
565 $_[0], 975 return $img
566 $_[1], 976 if FOCUS;
567 $_[2] * $img->w * .01, 977
568 $_[3] * $img->h * .01, 978 my $fade = @_ >= 1 ? $_[0] : defined $self->resource ("fade") ? $self->resource ("fade") * 0.01 : 0;
569 $_[4] * (3.14159265 / 180), 979 my $color = @_ >= 2 ? $_[1] : $self->resource ("color+" . urxvt::Color_fade);
570 ) 980
981 $img = $img->tint ($color) if $color ne "rgb:00/00/00";
982 $img = $img->muladd (1 - $fade, 0) if $fade;
983
984 $img
571 } 985 }
572 986
573=back 987=back
574 988
989=head2 OTHER STUFF
990
991Anything that didn't fit any of the other categories, even after applying
992force and closing our eyes.
993
994=over 4
995
996=item keep { ... }
997
998This operator takes a code block as argument, that is, one or more
999statements enclosed by braces.
1000
1001The trick is that this code block is only evaluated when the outcome
1002changes - on other calls the C<keep> simply returns the image it computed
1003previously (yes, it should only be used with images). Or in other words,
1004C<keep> I<caches> the result of the code block so it doesn't need to be
1005computed again.
1006
1007This can be extremely useful to avoid redoing slow operations - for
1008example, if your background expression takes the root background, blurs it
1009and then root-aligns it it would have to blur the root background on every
1010window move or resize.
1011
1012Another example is C<load>, which can be quite slow.
1013
1014In fact, urxvt itself encloses the whole expression in some kind of
1015C<keep> block so it only is reevaluated as required.
1016
1017Putting the blur into a C<keep> block will make sure the blur is only done
1018once, while the C<rootalign> is still done each time the window moves.
1019
1020 rootalign keep { blur 10, root }
1021
1022This leaves the question of how to force reevaluation of the block,
1023in case the root background changes: If expression inside the block
1024is sensitive to some event (root background changes, window geometry
1025changes), then it will be reevaluated automatically as needed.
1026
1027=cut
1028
1029 sub keep(&) {
1030 my $id = $_[0]+0;
1031
1032 local $frame = $self->{frame_cache}{$id} ||= [$frame];
1033
1034 unless ($frame->[FR_CACHE]) {
1035 $frame->[FR_CACHE] = [ $_[0]() ];
1036
1037 my $self = $self;
1038 my $frame = $frame;
1039 Scalar::Util::weaken $frame;
1040 $self->compile_frame ($frame, sub {
1041 # clear this frame cache, also for all parents
1042 for (my $frame = $frame; $frame; $frame = $frame->[0]) {
1043 undef $frame->[FR_CACHE];
1044 }
1045
1046 $self->recalculate;
1047 });
1048 };
1049
1050 # in scalar context we always return the first original result, which
1051 # is not quite how perl works.
1052 wantarray
1053 ? @{ $frame->[FR_CACHE] }
1054 : $frame->[FR_CACHE][0]
1055 }
1056
1057# sub keep_clear() {
1058# delete $self->{frame_cache};
1059# }
1060
1061=back
1062
575=cut 1063=cut
576 1064
577} 1065}
578 1066
579sub parse_expr { 1067sub parse_expr {
580 my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}"; 1068 my $expr = eval
1069 "sub {\n"
1070 . "package urxvt::bgdsl;\n"
1071 . "#line 0 'background expression'\n"
1072 . "$_[0]\n"
1073 . "}";
581 die if $@; 1074 die if $@;
582 $expr 1075 $expr
583} 1076}
584 1077
585# compiles a parsed expression 1078# compiles a parsed expression
586sub set_expr { 1079sub set_expr {
587 my ($self, $expr) = @_; 1080 my ($self, $expr) = @_;
588 1081
1082 $self->{root} = []; # the outermost frame
589 $self->{expr} = $expr; 1083 $self->{expr} = $expr;
590 $self->recalculate; 1084 $self->recalculate;
1085}
1086
1087# takes a hash of sensitivity indicators and installs watchers
1088sub compile_frame {
1089 my ($self, $frame, $cb) = @_;
1090
1091 my $state = $frame->[urxvt::bgdsl::FR_STATE] ||= {};
1092 my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
1093
1094 # don't keep stuff alive
1095 Scalar::Util::weaken $state;
1096
1097 if ($again->{nested}) {
1098 $state->{nested} = 1;
1099 } else {
1100 delete $state->{nested};
1101 }
1102
1103 if (my $interval = $again->{time}) {
1104 $state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
1105 if $state->{time}[0] != $interval;
1106
1107 # callback *might* have changed, although we could just rule that out
1108 $state->{time}[1]->cb (sub {
1109 ++$state->{counter};
1110 $cb->();
1111 });
1112 } else {
1113 delete $state->{time};
1114 }
1115
1116 if ($again->{position}) {
1117 $state->{position} = $self->on (position_change => $cb);
1118 } else {
1119 delete $state->{position};
1120 }
1121
1122 if ($again->{size}) {
1123 $state->{size} = $self->on (size_change => $cb);
1124 } else {
1125 delete $state->{size};
1126 }
1127
1128 if ($again->{rootpmap}) {
1129 $state->{rootpmap} = $self->on (rootpmap_change => $cb);
1130 } else {
1131 delete $state->{rootpmap};
1132 }
1133
1134 if ($again->{focus}) {
1135 $state->{focus} = $self->on (focus_in => $cb, focus_out => $cb);
1136 } else {
1137 delete $state->{focus};
1138 }
591} 1139}
592 1140
593# evaluate the current bg expression 1141# evaluate the current bg expression
594sub recalculate { 1142sub recalculate {
595 my ($arg_self) = @_; 1143 my ($arg_self) = @_;
605 1153
606 $arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL; 1154 $arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
607 1155
608 # set environment to evaluate user expression 1156 # set environment to evaluate user expression
609 1157
610 local $self = $arg_self; 1158 local $self = $arg_self;
611
612 local $HOME = $ENV{HOME}; 1159 local $HOME = $ENV{HOME};
613 local $old = $self->{state}; 1160 local $frame = $self->{root};
614 local $new = my $state = $self->{state} = {};
615 1161
616 ($x, $y, $w, $h) =
617 $self->background_geometry ($self->{border}); 1162 ($x, $y, $w, $h) = $self->background_geometry ($self->{border});
1163 $focus = $self->focus;
618 1164
619 # evaluate user expression 1165 # evaluate user expression
620 1166
621 my $img = eval { $self->{expr}->() }; 1167 my @img = eval { $self->{expr}->() };
622 warn $@ if $@;#d# 1168 die $@ if $@;
1169 die "background-expr did not return anything.\n" unless @img;
1170 die "background-expr: expected image(s), got something else.\n"
623 die if !UNIVERSAL::isa $img, "urxvt::img"; 1171 if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
624 1172
625 $state->{size_sensitive} = 1 1173 my $img = urxvt::bgdsl::merge @img;
1174
1175 $frame->[FR_AGAIN]{size} = 1
626 if $img->repeat_mode != urxvt::RepeatNormal; 1176 if $img->repeat_mode != urxvt::RepeatNormal;
627 1177
628 # if the expression is sensitive to external events, prepare reevaluation then 1178 # if the expression is sensitive to external events, prepare reevaluation then
629 1179 $self->compile_frame ($frame, sub { $arg_self->recalculate });
630 my $repeat;
631
632 if (my $again = $state->{again}) {
633 $repeat = 1;
634 my $self = $self;
635 $state->{timer} = $again == $old->{again}
636 ? $old->{timer}
637 : urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
638 ++$self->{counter};
639 $self->recalculate
640 });
641 }
642
643 if (delete $state->{position_sensitive}) {
644 $repeat = 1;
645 $self->enable (position_change => sub { $_[0]->recalculate });
646 } else {
647 $self->disable ("position_change");
648 }
649
650 if (delete $state->{size_sensitive}) {
651 $repeat = 1;
652 $self->enable (size_change => sub { $_[0]->recalculate });
653 } else {
654 $self->disable ("size_change");
655 }
656
657 if (delete $state->{rootpmap_sensitive}) {
658 $repeat = 1;
659 $self->enable (rootpmap_change => sub { $_[0]->recalculate });
660 } else {
661 $self->disable ("rootpmap_change");
662 }
663 1180
664 # clear stuff we no longer need 1181 # clear stuff we no longer need
665 1182
666 %$old = (); 1183# unless (%{ $frame->[FR_STATE] }) {
667
668 unless ($repeat) {
669 delete $self->{state}; 1184# delete $self->{state};
670 delete $self->{expr}; 1185# delete $self->{expr};
671 } 1186# }
672 1187
673 # set background pixmap 1188 # set background pixmap
674 1189
675 $self->set_background ($img, $self->{border}); 1190 $self->set_background ($img, $self->{border});
676 $self->scr_recolour (0); 1191 $self->scr_recolour (0);
678} 1193}
679 1194
680sub on_start { 1195sub on_start {
681 my ($self) = @_; 1196 my ($self) = @_;
682 1197
683 my $expr = $self->x_resource ("background.expr") 1198 my $expr = $self->x_resource ("%.expr")
684 or return; 1199 or return;
685 1200
1201 $self->has_render
1202 or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
1203
686 $self->set_expr (parse_expr $expr); 1204 $self->set_expr (parse_expr $expr);
687 $self->{border} = $self->x_resource_boolean ("background.border"); 1205 $self->{border} = $self->x_resource_boolean ("%.border");
1206
1207 $MIN_INTERVAL = $self->x_resource ("%.interval");
688 1208
689 () 1209 ()
690} 1210}
691 1211

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