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Revision 1.35 by root, Fri Jun 8 08:06:38 2012 UTC vs.
Revision 1.85 by root, Thu Oct 3 01:11:48 2013 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:%.border.:boolean:respect the terminal border 4#:META:X_RESOURCE:%.border:boolean:respect the terminal border
5#:META:X_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 rxvt -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
43This extension manages the terminal background by creating a picture that
44is behind the text, replacing the normal background colour.
45
46It does so by evaluating a Perl expression that I<calculates> the image on
47the fly, for example, by grabbing the root background or loading a file.
48
49While the full power of Perl is available, the operators have been design
50to be as simple as possible.
51
52For example, to load an image and scale it to the window size, you would
53use:
54
55 urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
56
57Or specified as a X resource:
58
59 URxvt.background-expr: scale keep { load "/path/to/mybg.png" }
60
61=head1 THEORY OF OPERATION
62
63At startup, just before the window is mapped for the first time, the
64expression is evaluated and must yield an image. The image is then
65extended as necessary to cover the whole terminal window, and is set as a
66background pixmap.
67
68If the image contains an alpha channel, then it will be used as-is in
69visuals that support alpha channels (for example, for a compositing
70manager). In other visuals, the terminal background colour will be used to
71replace any transparency.
72
73When the expression relies, directly or indirectly, on the window size,
74position, the root pixmap, or a timer, then it will be remembered. If not,
75then it will be removed.
76
77If any of the parameters that the expression relies on changes (when the
78window is moved or resized, its position or size changes; when the root
79pixmap is replaced by another one the root background changes; or when the
80timer elapses), then the expression will be evaluated again.
81
82For example, an expression such as C<scale keep { load "$HOME/mybg.png"
83}> scales the image to the window size, so it relies on the window size
84and will be reevaluated each time it is changed, but not when it moves for
85example. That ensures that the picture always fills the terminal, even
86after its size changes.
87
88=head2 EXPRESSIONS
89
90Expressions are normal Perl expressions, in fact, they are Perl blocks -
91which means you could use multiple lines and statements:
92
93 scale keep {
94 again 3600;
95 if (localtime now)[6]) {
96 return load "$HOME/weekday.png";
97 } else {
98 return load "$HOME/sunday.png";
99 }
100 }
101
102This inner expression is evaluated once per hour (and whenever the
103terminal window is resized). It sets F<sunday.png> as background on
104Sundays, and F<weekday.png> on all other days.
105
106Fortunately, we expect that most expressions will be much simpler, with
107little Perl knowledge needed.
108
109Basically, you always start with a function that "generates" an image
110object, such as C<load>, which loads an image from disk, or C<root>, which
111returns the root window background image:
112
113 load "$HOME/mypic.png"
114
115The path is usually specified as a quoted string (the exact rules can be
116found in the L<perlop> manpage). The F<$HOME> at the beginning of the
117string is expanded to the home directory.
118
119Then you prepend one or more modifiers or filtering expressions, such as
120C<scale>:
121
122 scale load "$HOME/mypic.png"
123
124Just like a mathematical expression with functions, you should read these
125expressions from right to left, as the C<load> is evaluated first, and
126its result becomes the argument to the C<scale> function.
127
128Many operators also allow some parameters preceding the input image
129that modify its behaviour. For example, C<scale> without any additional
130arguments scales the image to size of the terminal window. If you specify
131an additional argument, it uses it as a scale factor (multiply by 100 to
132get a percentage):
133
134 scale 2, load "$HOME/mypic.png"
135
136This enlarges the image by a factor of 2 (200%). As you can see, C<scale>
137has now two arguments, the C<200> and the C<load> expression, while
138C<load> only has one argument. Arguments are separated from each other by
139commas.
140
141Scale also accepts two arguments, which are then separate factors for both
142horizontal and vertical dimensions. For example, this halves the image
143width and doubles the image height:
144
145 scale 0.5, 2, load "$HOME/mypic.png"
146
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:
151
152 scale 0.5, 2, keep { load "$HOME/mypic.png" }
153
154The C<keep> operator executes all the statements inside the braces only
155once, or when it thinks the outcome might change. In other cases it
156returns the last value computed by the brace block.
157
158This means that the C<load> is only executed once, which makes it much
159faster, but also means that more memory is being used, because the loaded
160image must be kept in memory at all times. In this expression, the
161trade-off is likely worth it.
162
163But back to effects: Other effects than scaling are also readily
164available, for example, you can tile the image to fill the whole window,
165instead of resizing it:
166
167 tile keep { load "$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
17=head2 REFERENCE 250=head1 REFERENCE
18 251
19=cut 252=head2 COMMAND LINE SWITCHES
20 253
21our $EXPR; 254=over 4
22#$EXPR = 'move W * 0.1, -H * 0.1, resize W * 0.5, H * 0.5, repeat_none load "opensource.png"';
23$EXPR = 'move -TX, -TY, load "argb.png"';
24#$EXPR = '
25# rotate W, H, 50, 50, counter 1/59.95, repeat_mirror,
26# clip X, Y, W, H, repeat_mirror,
27# load "/root/pix/das_fette_schwein.jpg"
28#';
29#$EXPR = 'solid "red"';
30#$EXPR = 'blur root, 10, 10'
31#$EXPR = 'blur move (root, -x, -y), 5, 5'
32#resize load "/root/pix/das_fette_schwein.jpg", w, h
33 255
34our ($self, $old, $new); 256=item --background-expr perl-expression
257
258Specifies the Perl expression to evaluate.
259
260=item --background-border
261
262By default, the expression creates an image that fills the full window,
263overwriting borders and any other areas, such as the scrollbar.
264
265Specifying this flag changes the behaviour, so that the image only
266replaces the background of the character area.
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
277=back
278
279=cut
280
281our %_IMG_CACHE;
282our $HOME;
283our ($self, $frame);
35our ($x, $y, $w, $h); 284our ($x, $y, $w, $h, $focus);
36 285
37# enforce at least this interval between updates 286# enforce at least this interval between updates
38our $MIN_INTERVAL = 1/100; 287our $MIN_INTERVAL = 6/59.951;
39 288
40{ 289{
41 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);
42 298
43=head2 PROVIDERS/GENERATORS 299=head2 PROVIDERS/GENERATORS
44 300
45These functions provide an image, by loading it from disk, grabbing it 301These functions provide an image, by loading it from disk, grabbing it
46from 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
51=item load $path 307=item load $path
52 308
53Loads the image at the given C<$path>. The image is set to plane tiling 309Loads the image at the given C<$path>. The image is set to plane tiling
54mode. 310mode.
55 311
56Loaded 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.
57 314
315=item load_uc $path
316
317Load uncached - same as load, but does not cache the image, which means it
318is I<always> loaded from the filesystem again, even if another copy of it
319is in memory at the time.
320
58=cut 321=cut
322
323 sub load_uc($) {
324 $self->new_img_from_file ($_[0])
325 }
59 326
60 sub load($) { 327 sub load($) {
61 my ($path) = @_; 328 my ($path) = @_;
62 329
63 $new->{load}{$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 }
64 } 335 }
65 336
66=item root 337=item root
67 338
68Returns the root window pixmap, that is, hopefully, the background image 339Returns the root window pixmap, that is, hopefully, the background image
69of your screen. The image is set to extend mode. 340of your screen.
70 341
71This function makes your expression root sensitive, that means it will be 342This function makes your expression root sensitive, that means it will be
72reevaluated when the bg image changes. 343reevaluated when the bg image changes.
73 344
74=cut 345=cut
75 346
76 sub root() { 347 sub root() {
77 $new->{rootpmap_sensitive} = 1; 348 $frame->[FR_AGAIN]{rootpmap} = 1;
78 die "root op not supported, exg, we need you"; 349 $self->new_img_from_root
79 } 350 }
80 351
81=item solid $colour 352=item solid $colour
82 353
83=item solid $width, $height, $colour 354=item solid $width, $height, $colour
84 355
85Creates a new image and completely fills it with the given colour. The 356Creates a new image and completely fills it with the given colour. The
86image is set to tiling mode. 357image is set to tiling mode.
87 358
88If <$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
89useful for solid backgrounds or for use in filtering effects. 360useful for solid backgrounds or for use in filtering effects.
90 361
91=cut 362=cut
92 363
93 sub solid($$;$) { 364 sub solid($;$$) {
94 my $colour = pop; 365 my $colour = pop;
95 366
96 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);
97 $img->fill ($colour); 368 $img->fill ($colour);
98 $img 369 $img
99 } 370 }
100 371
101=back 372=item clone $img
102 373
103=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.
104 376
105The following functions provide variable data such as the terminal
106window dimensions. Most of them make your expression sensitive to some
107events, for example using C<TW> (terminal width) means your expression is
108evaluated again when the terminal is resized.
109
110=over 4
111
112=item TX
113
114=item TY
115
116Return the X and Y coordinates of the terminal window (the terminal
117window is the full window by default, and the character area only when in
118border-respect mode).
119
120Using these functions make your expression sensitive to window moves.
121
122These functions are mainly useful to align images to the root window.
123
124Example: load an image and align it so it looks as if anchored to the
125background.
126
127 move -TX, -TY, load "mybg.png"
128
129=item TW
130
131Return the width (C<TW>) and height (C<TH>) of the terminal window (the
132terminal window is the full window by default, and the character area only
133when in border-respect mode).
134
135Using these functions make your expression sensitive to window resizes.
136
137These functions are mainly useful to scale images, or to clip images to
138the window size to conserve memory.
139
140Example: take the screen background, clip it to the window size, blur it a
141bit, align it to the window position and use it as background.
142
143 clip move -TX, -TY, blur 5, root
144
145=cut 377=cut
146 378
147 sub TX() { $new->{position_sensitive} = 1; $x }
148 sub TY() { $new->{position_sensitive} = 1; $y }
149 sub TW() { $new->{size_sensitive} = 1; $w }
150 sub TH() { $new->{size_sensitive} = 1; $h }
151
152=item now
153
154Returns the current time as (fractional) seconds since the epoch.
155
156Using this expression does I<not> make your expression sensitive to time,
157but the next two functions do.
158
159=item again $seconds
160
161When this function is used the expression will be reevaluated again in
162C<$seconds> seconds.
163
164Example: load some image and rotate it according to the time of day (as if it were
165the hour pointer of a clock). update this image every minute.
166
167 again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
168
169=item counter $seconds
170
171Like C<again>, but also returns an increasing counter value, starting at
1720, which might be useful for some simple animation effects.
173
174=cut
175
176 sub now() { urxvt::NOW }
177
178 sub again($) {
179 $new->{again} = $_[0];
180 }
181
182 sub counter($) { 379 sub clone($) {
183 $new->{again} = $_[0]; 380 $_[0]->clone
184 $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
185 } 425 }
186 426
187=back 427=back
188 428
189=head2 TILING MODES 429=head2 TILING MODES
209Similar to tile, but reflects the image each time it uses a new copy, so 449Similar to tile, but reflects the image each time it uses a new copy, so
210that top edges always touch top edges, right edges always touch right 450that top edges always touch top edges, right edges always touch right
211edges and so on (with normal tiling, left edges always touch right edges 451edges and so on (with normal tiling, left edges always touch right edges
212and top always touch bottom edges). 452and top always touch bottom edges).
213 453
214Exmaple: load an image and mirror it over the background, avoiding sharp 454Example: load an image and mirror it over the background, avoiding sharp
215edges at the image borders at the expense of mirroring the image itself 455edges at the image borders at the expense of mirroring the image itself
216 456
217 mirror load "mybg.png" 457 mirror load "mybg.png"
218 458
219=item pad $img 459=item pad $img
221Takes an image and modifies it so that all pixels outside the image area 461Takes an image and modifies it so that all pixels outside the image area
222become 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
223image over another image or the background colour while leaving all 463image over another image or the background colour while leaving all
224background pixels outside the image unchanged. 464background pixels outside the image unchanged.
225 465
226Example: load an image and display it in the upper left corner. The rets 466Example: load an image and display it in the upper left corner. The rest
227of the space is left "empty" (transparent or wahtever your compisotr does 467of the space is left "empty" (transparent or whatever your compositor does
228in alpha mode, else background colour). 468in alpha mode, else background colour).
229 469
230 pad load "mybg.png" 470 pad load "mybg.png"
231 471
232=item extend $img 472=item extend $img
233 473
234Extends 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
235area 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
236filtering operations and want the pixels outside the image to have the 476filtering operations and want the pixels outside the image to have the
237same values as the pixels near the edge. 477same values as the pixels near the edge.
238 478
239Example: just for curiosity, how does this pixel extension stuff work? 479Example: just for curiosity, how does this pixel extension stuff work?
240 480
266 $img 506 $img
267 } 507 }
268 508
269=back 509=back
270 510
271=head2 PIXEL OPERATORS 511=head2 VARIABLE VALUES
272 512
273The 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.
274 518
275=over 4 519=over 4
276 520
277=item clone $img 521=item TX
278 522
279Returns an exact copy of the image. 523=item TY
280 524
281=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).
282 528
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 bacckground 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} = $_[0];
609 }
610
283 sub clone($) { 611 sub counter($) {
284 $_[0]->clone 612 $frame->[FR_AGAIN]{time} = $_[0];
613 $frame->[FR_STATE]{counter} + 0
285 } 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
286 623
287=item clip $img 624=item clip $img
288 625
289=item clip $width, $height, $img 626=item clip $width, $height, $img
290 627
293Clips an image to the given rectangle. If the rectangle is outside the 630Clips an image to the given rectangle. If the rectangle is outside the
294image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is 631image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is
295larger than the image, then the tiling mode defines how the extra pixels 632larger than the image, then the tiling mode defines how the extra pixels
296will be filled. 633will be filled.
297 634
298If C<$x> an C<$y> are missing, then C<0> is assumed for both. 635If C<$x> and C<$y> are missing, then C<0> is assumed for both.
299 636
300If C<$width> and C<$height> are missing, then the window size will be 637If C<$width> and C<$height> are missing, then the window size will be
301assumed. 638assumed.
302 639
303Example: load an image, blur it, and clip it to the window size to save 640Example: load an image, blur it, and clip it to the window size to save
304memory. 641memory.
305 642
306 clip blur 10, load "mybg.png" 643 clip keep { blur 10, load "mybg.png" }
307 644
308=cut 645=cut
309 646
310 sub clip($;$$;$$) { 647 sub clip($;$$;$$) {
311 my $img = pop; 648 my $img = pop;
314 $img->sub_rect ($_[0], $_[1], $w, $h) 651 $img->sub_rect ($_[0], $_[1], $w, $h)
315 } 652 }
316 653
317=item scale $img 654=item scale $img
318 655
319=item scale $size_percent, $img 656=item scale $size_factor, $img
320 657
321=item scale $width_percent, $height_percent, $img 658=item scale $width_factor, $height_factor, $img
322 659
323Scales the image by the given percentages in horizontal 660Scales the image by the given factors in horizontal
324(C<$width_percent>) and vertical (C<$height_percent>) direction. 661(C<$width>) and vertical (C<$height>) direction.
325 662
326If only one percentage is give, it is used for both directions. 663If only one factor is given, it is used for both directions.
327 664
328If 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
329keeping aspect. 666keeping aspect.
330 667
331=item resize $width, $height, $img 668=item resize $width, $height, $img
332 669
333Resizes the image to exactly C<$width> times C<$height> pixels. 670Resizes the image to exactly C<$width> times C<$height> pixels.
334 671
335=cut 672=item fit $img
336 673
337#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, $img
683
684Similar to C<fit>, but shrinks or grows until all of the area is covered
685by the image, so instead of potentially leaving borders, it will cut off
686image data that doesn't fit.
687
688=cut
338 689
339 sub scale($;$;$) { 690 sub scale($;$;$) {
340 my $img = pop; 691 my $img = pop;
341 692
342 @_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01) 693 @_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
343 : @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01) 694 : @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
344 : $img->scale (TW, TH) 695 : $img->scale (TW, TH)
345 } 696 }
346 697
347 sub resize($$$) { 698 sub resize($$$) {
348 my $img = pop; 699 my $img = pop;
349 $img->scale ($_[0], $_[1]) 700 $img->scale ($_[0], $_[1])
350 } 701 }
702
703 sub fit($;$$) {
704 my $img = pop;
705 my $w = ($_[0] || TW) / $img->w;
706 my $h = ($_[1] || TH) / $img->h;
707 scale +(min $w, $h), $img
708 }
709
710 sub cover($;$$) {
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
717=item move $dx, $dy, $img
718
719Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
720the vertical.
721
722Example: move the image right by 20 pixels and down by 30.
723
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" }
748
749=item rootalign $img
750
751Moves the image so that it appears glued to the screen as opposed to the
752window. This gives the illusion of a larger area behind the window. It is
753exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
754top left of the screen.
755
756Example: load a background image, put it in mirror mode and root align it.
757
758 rootalign keep { mirror load "mybg.png" }
759
760Example: take the screen background and align it, giving the illusion of
761transparency as long as the window isn't in front of other windows.
762
763 rootalign root
764
765=cut
351 766
352 sub move($$;$) { 767 sub move($$;$) {
353 my $img = pop->clone; 768 my $img = pop->clone;
354 $img->move ($_[0], $_[1]); 769 $img->move ($_[0], $_[1]);
355 $img 770 $img
356 } 771 }
357 772
773 sub align($;$$) {
774 my $img = pop;
775
776 move $_[0] * (TW - $img->w),
777 $_[1] * (TH - $img->h),
778 $img
779 }
780
781 sub center($;$$) {
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), $img
787 }
788
789 sub rootalign($) {
790 move -TX, -TY, $_[0]
791 }
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
358 sub rotate($$$$$$) { 804 sub rotate($$$$) {
359 my $img = pop; 805 my $img = pop;
360 $img->rotate ( 806 $img->rotate (
361 $_[0], 807 $_[0] * ($img->w + $img->x),
362 $_[1], 808 $_[1] * ($img->h + $img->y),
363 $_[2] * $img->w * .01,
364 $_[3] * $img->h * .01,
365 $_[4] * (3.14159265 / 180), 809 $_[2] * (3.14159265 / 180),
366 ) 810 )
367 } 811 }
812
813=back
814
815=head2 COLOUR MODIFICATIONS
816
817The following operators change the pixels of the image.
818
819=over 4
820
821=item tint $color, $img
822
823Tints the image in the given colour.
824
825Example: tint the image red.
826
827 tint "red", load "rgb.png"
828
829Example: the same, but specify the colour by component.
830
831 tint [1, 0, 0], load "rgb.png"
832
833=cut
834
835 sub tint($$) {
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($$) {
846 $_[1]->shade ($_[0])
847 }
848
849=item contrast $factor, $img
850
851=item contrast $r, $g, $b, $img
852
853=item contrast $r, $g, $b, $a, $img
854
855Adjusts the I<contrast> of an image.
856
857The first form applies a single C<$factor> to red, green and blue, the
858second form applies separate factors to each colour channel, and the last
859form includes the alpha channel.
860
861Values from 0 to 1 lower the contrast, values higher than 1 increase the
862contrast.
863
864Due to limitations in the underlying XRender extension, lowering contrast
865also reduces brightness, while increasing contrast currently also
866increases brightness.
867
868=item brightness $bias, $img
869
870=item brightness $r, $g, $b, $img
871
872=item brightness $r, $g, $b, $a, $img
873
874Adjusts the brightness of an image.
875
876The first form applies a single C<$bias> to red, green and blue, the
877second form applies separate biases to each colour channel, and the last
878form includes the alpha channel.
879
880Values less than 0 reduce brightness, while values larger than 0 increase
881it. Useful range is from -1 to 1 - the former results in a black, the
882latter in a white picture.
883
884Due to idiosyncrasies in the underlying XRender extension, biases less
885than zero can be I<very> slow.
886
887You can also try the experimental(!) C<muladd> operator.
888
889=cut
890
891 sub contrast($$;$$;$) {
892 my $img = pop;
893 my ($r, $g, $b, $a) = @_;
894
895 ($g, $b) = ($r, $r) if @_ < 3;
896 $a = 1 if @_ < 4;
897
898 $img = $img->clone;
899 $img->contrast ($r, $g, $b, $a);
900 $img
901 }
902
903 sub brightness($$;$$;$) {
904 my $img = pop;
905 my ($r, $g, $b, $a) = @_;
906
907 ($g, $b) = ($r, $r) if @_ < 3;
908 $a = 1 if @_ < 4;
909
910 $img = $img->clone;
911 $img->brightness ($r, $g, $b, $a);
912 $img
913 }
914
915=item muladd $mul, $add, $img # EXPERIMENTAL
916
917First multiplies the pixels by C<$mul>, then adds C<$add>. This can be used
918to implement brightness and contrast at the same time, with a wider value
919range than contrast and brightness operators.
920
921Due to numerous bugs in XRender implementations, it can also introduce a
922number of visual artifacts.
923
924Example: increase contrast by a factor of C<$c> without changing image
925brightness too much.
926
927 muladd $c, (1 - $c) * 0.5, $img
928
929=cut
930
931 sub muladd($$$) {
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
368 948
369 sub blur($$;$) { 949 sub blur($$;$) {
370 my $img = pop; 950 my $img = pop;
371 $img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0]) 951 $img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
372 } 952 }
373 953
374 sub contrast($$;$$;$) { 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<$factor> is the real value, not a percentage value (that is, 0..1, not
9640..100).
965
966Example: do the right thing when focus fading is requested.
967
968 focus_fade load "mybg.jpg";
969
970=cut
971
972 sub focus_fade($;$$) {
375 my $img = pop; 973 my $img = pop;
376 my ($r, $g, $b, $a) = @_;
377 974
378 ($g, $b) = ($r, $r) if @_ < 4; 975 return $img
379 $a = 1 if @_ < 5; 976 if FOCUS;
380 977
381 $img = $img->clone; 978 my $fade = @_ >= 1 ? $_[0] : defined $self->resource ("fade") ? $self->resource ("fade") * 0.01 : 0;
382 $img->contrast ($r, $g, $b, $a); 979 my $color = @_ >= 2 ? $_[1] : $self->resource ("color+" . urxvt::Color_fade);
980
981 $img = $img->tint ($color) if $color ne "rgb:00/00/00";
982 $img = $img->muladd (1 - $fade, 0) if $fade;
983
383 $img 984 $img
384 } 985 }
385 986
386 sub brightness($$;$$;$) {
387 my $img = pop;
388 my ($r, $g, $b, $a) = @_;
389
390 ($g, $b) = ($r, $r) if @_ < 4;
391 $a = 1 if @_ < 5;
392
393 $img = $img->clone;
394 $img->brightness ($r, $g, $b, $a);
395 $img
396 }
397
398=back 987=back
399 988
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
400=cut 1063=cut
401 1064
402} 1065}
403 1066
404sub parse_expr { 1067sub parse_expr {
405 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 . "}";
406 die if $@; 1074 die if $@;
407 $expr 1075 $expr
408} 1076}
409 1077
410# compiles a parsed expression 1078# compiles a parsed expression
411sub set_expr { 1079sub set_expr {
412 my ($self, $expr) = @_; 1080 my ($self, $expr) = @_;
413 1081
1082 $self->{root} = []; # the outermost frame
414 $self->{expr} = $expr; 1083 $self->{expr} = $expr;
415 $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 $state->{focus};
1138 }
416} 1139}
417 1140
418# evaluate the current bg expression 1141# evaluate the current bg expression
419sub recalculate { 1142sub recalculate {
420 my ($arg_self) = @_; 1143 my ($arg_self) = @_;
430 1153
431 $arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL; 1154 $arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
432 1155
433 # set environment to evaluate user expression 1156 # set environment to evaluate user expression
434 1157
435 local $self = $arg_self; 1158 local $self = $arg_self;
436 1159 local $HOME = $ENV{HOME};
437 local $old = $self->{state}; 1160 local $frame = $self->{root};
438 local $new = my $state = $self->{state} = {};
439 1161
440 ($x, $y, $w, $h) =
441 $self->background_geometry ($self->{border}); 1162 ($x, $y, $w, $h) = $self->background_geometry ($self->{border});
1163 $focus = $self->focus;
442 1164
443 # evaluate user expression 1165 # evaluate user expression
444 1166
445 my $img = eval { $self->{expr}->() }; 1167 my @img = eval { $self->{expr}->() };
446 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"
447 die if !UNIVERSAL::isa $img, "urxvt::img"; 1171 if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
448 1172
449 $state->{size_sensitive} = 1 1173 my $img = urxvt::bgdsl::merge @img;
1174
1175 $frame->[FR_AGAIN]{size} = 1
450 if $img->repeat_mode != urxvt::RepeatNormal; 1176 if $img->repeat_mode != urxvt::RepeatNormal;
451 1177
452 # if the expression is sensitive to external events, prepare reevaluation then 1178 # if the expression is sensitive to external events, prepare reevaluation then
453 1179 $self->compile_frame ($frame, sub { $arg_self->recalculate });
454 my $repeat;
455
456 if (my $again = $state->{again}) {
457 $repeat = 1;
458 my $self = $self;
459 $state->{timer} = $again == $old->{again}
460 ? $old->{timer}
461 : urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
462 ++$self->{counter};
463 $self->recalculate
464 });
465 }
466
467 if (delete $state->{position_sensitive}) {
468 $repeat = 1;
469 $self->enable (position_change => sub { $_[0]->recalculate });
470 } else {
471 $self->disable ("position_change");
472 }
473
474 if (delete $state->{size_sensitive}) {
475 $repeat = 1;
476 $self->enable (size_change => sub { $_[0]->recalculate });
477 } else {
478 $self->disable ("size_change");
479 }
480
481 if (delete $state->{rootpmap_sensitive}) {
482 $repeat = 1;
483 $self->enable (rootpmap_change => sub { $_[0]->recalculate });
484 } else {
485 $self->disable ("rootpmap_change");
486 }
487 1180
488 # clear stuff we no longer need 1181 # clear stuff we no longer need
489 1182
490 %$old = (); 1183# unless (%{ $frame->[FR_STATE] }) {
491
492 unless ($repeat) {
493 delete $self->{state}; 1184# delete $self->{state};
494 delete $self->{expr}; 1185# delete $self->{expr};
495 } 1186# }
496 1187
497 # set background pixmap 1188 # set background pixmap
498 1189
499 $self->set_background ($img, $self->{border}); 1190 $self->set_background ($img, $self->{border});
500 $self->scr_recolour (0); 1191 $self->scr_recolour (0);
502} 1193}
503 1194
504sub on_start { 1195sub on_start {
505 my ($self) = @_; 1196 my ($self) = @_;
506 1197
507 my $expr = $self->x_resource ("background.expr") 1198 my $expr = $self->x_resource ("%.expr")
508 or return; 1199 or return;
509 1200
1201 $self->has_render
1202 or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
1203
510 $self->set_expr (parse_expr $expr); 1204 $self->set_expr (parse_expr $expr);
511 $self->{border} = $self->x_resource_boolean ("background.border"); 1205 $self->{border} = $self->x_resource_boolean ("%.border");
1206
1207 $MIN_INTERVAL = $self->x_resource ("%.interval");
512 1208
513 () 1209 ()
514} 1210}
515 1211

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