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Revision 1.50 by root, Sun Jun 10 17:31:53 2012 UTC vs.
Revision 1.109 by root, Tue Nov 29 08:48:22 2022 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:X_RESOURCE:%.interval:seconds:minimum time between updates	5	#:META:RESOURCE:%.interval:seconds:minimum time between updates
		6	#:META:RESOURCE:pixmap:file[;geom]:set image as background
		7	#:META:RESOURCE:backgroundPixmap:file[;geom]:set image as background
		8	#:META:RESOURCE:tr:boolean:set root pixmap as background
		9	#:META:RESOURCE:transparent:boolean:set root pixmap as background
		10	#:META:RESOURCE:tint:color:tint background with color
		11	#:META:RESOURCE:tintColor:color:tint background with color
		12	#:META:RESOURCE:sh:number:shade background by number %
		13	#:META:RESOURCE:shading:number:shade background by number %
		14	#:META:RESOURCE:blr:HxV:gaussian-blur background with radii
		15	#:META:RESOURCE:blurRadius:HxV:gaussian-blur background with radii
		16	#:META:OSC:20:change/query background image
		17	#:META:OSC:705:change transparent background tint colour
6		18
7	=head1 NAME	19	=head1 NAME
8		20
9	background - manage terminal background	21	background - manage terminal background
10		22
11	=head1 SYNOPSIS	23	=head1 SYNOPSIS
12		24
13	urxvt --background-expr 'background expression'	25	urxvt --background-expr 'background expression'
14	--background-border	26	--background-border
15	--background-interval seconds	27	--background-interval seconds
16		28
		29	=head1 QUICK AND DIRTY CHEAT SHEET
		30
		31	Load a random jpeg image and tile the background with it without scaling
		32	or anything else:
		33
		34	load "/path/to/img.jpg"
		35
		36	The same, but use mirroring/reflection instead of tiling:
		37
		38	mirror load "/path/to/img.jpg"
		39
		40	Load an image and scale it to exactly fill the terminal window:
		41
		42	scale keep { load "/path/to/img.jpg" }
		43
		44	Implement pseudo-transparency by using a suitably-aligned root pixmap
		45	as window background:
		46
		47	rootalign root
		48
		49	Likewise, but keep a blurred copy:
		50
		51	rootalign keep { blur 10, root }
		52
17	=head1 DESCRIPTION	53	=head1 DESCRIPTION
18		54
19	This extension manages the terminal background by creating a picture that	55	This extension manages the terminal background by creating a picture that
20	is behind the text, replacing the normal background colour.	56	is behind the text, replacing the normal background colour.
21		57
22	It does so by evaluating a Perl expression that I<calculates> the image on	58	It does so by evaluating a Perl expression that I<calculates> the image on
23	the fly, for example, by grabbing the root background or loading a file.	59	the fly, for example, by grabbing the root background or loading a file.
24		60
25	While the full power of Perl is available, the operators have been design	61	While the full power of Perl is available, the operators have been
26	to be as simple as possible.	62	designed to be as simple as possible.
27		63
28	For example, to load an image and scale it to the window size, you would	64	For example, to load an image and scale it to the window size, you would
29	use:	65	use:
30		66
31	urxvt --background-expr 'scale load "/path/to/mybg.png"'	67	urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
32		68
33	Or specified as a X resource:	69	Or specified as a X resource:
34		70
35	URxvt.background-expr: scale load "/path/to/mybg.png"	71	URxvt.background.expr: scale keep { load "/path/to/mybg.png" }
36		72
37	=head1 THEORY OF OPERATION	73	=head1 THEORY OF OPERATION
38		74
39	At startup, just before the window is mapped for the first time, the	75	At startup, just before the window is mapped for the first time, the
40	expression is evaluated and must yield an image. The image is then	76	expression is evaluated and must yield an image. The image is then
…		…
53	If any of the parameters that the expression relies on changes (when the	89	If any of the parameters that the expression relies on changes (when the
54	window is moved or resized, its position or size changes; when the root	90	window is moved or resized, its position or size changes; when the root
55	pixmap is replaced by another one the root background changes; or when the	91	pixmap is replaced by another one the root background changes; or when the
56	timer elapses), then the expression will be evaluated again.	92	timer elapses), then the expression will be evaluated again.
57		93
58	For example, an expression such as C<scale load "$HOME/mybg.png"> scales the	94	For example, an expression such as C<scale keep { load "$HOME/mybg.png"
59	image to the window size, so it relies on the window size and will	95	}> scales the image to the window size, so it relies on the window size
60	be reevaluated each time it is changed, but not when it moves for	96	and will be reevaluated each time it is changed, but not when it moves for
61	example. That ensures that the picture always fills the terminal, even	97	example. That ensures that the picture always fills the terminal, even
62	after it's size changes.	98	after its size changes.
63		99
64	=head2 EXPRESSIONS	100	=head2 EXPRESSIONS
65		101
66	Expressions are normal Perl expressions, in fact, they are Perl blocks -	102	Expressions are normal Perl expressions, in fact, they are Perl blocks -
67	which means you could use multiple lines and statements:	103	which means you could use multiple lines and statements:
68		104
		105	scale keep {
69	again 3600;	106	again 3600;
70	if (localtime now)[6]) {	107	if (localtime now)[6]) {
71	return scale load "$HOME/weekday.png";	108	return load "$HOME/weekday.png";
72	} else {	109	} else {
73	return scale load "$HOME/sunday.png";	110	return load "$HOME/sunday.png";
		111	}
74	}	112	}
75		113
76	This expression gets evaluated once per hour. It will set F<sunday.png> as	114	This inner expression is evaluated once per hour (and whenever the
		115	terminal window is resized). It sets F<sunday.png> as background on
77	background on Sundays, and F<weekday.png> on all other days.	116	Sundays, and F<weekday.png> on all other days.
78		117
79	Fortunately, we expect that most expressions will be much simpler, with	118	Fortunately, we expect that most expressions will be much simpler, with
80	little Perl knowledge needed.	119	little Perl knowledge needed.
81		120
82	Basically, you always start with a function that "generates" an image	121	Basically, you always start with a function that "generates" an image
…		…
105	get a percentage):	144	get a percentage):
106		145
107	scale 2, load "$HOME/mypic.png"	146	scale 2, load "$HOME/mypic.png"
108		147
109	This enlarges the image by a factor of 2 (200%). As you can see, C<scale>	148	This enlarges the image by a factor of 2 (200%). As you can see, C<scale>
110	has now two arguments, the C<200> and the C<load> expression, while	149	has now two arguments, the C<2> and the C<load> expression, while
111	C<load> only has one argument. Arguments are separated from each other by	150	C<load> only has one argument. Arguments are separated from each other by
112	commas.	151	commas.
113		152
114	Scale also accepts two arguments, which are then separate factors for both	153	Scale also accepts two arguments, which are then separate factors for both
115	horizontal and vertical dimensions. For example, this halves the image	154	horizontal and vertical dimensions. For example, this halves the image
116	width and doubles the image height:	155	width and doubles the image height:
117		156
118	scale 0.5, 2, load "$HOME/mypic.png"	157	scale 0.5, 2, load "$HOME/mypic.png"
119		158
120	Other effects than scalign are also readily available, for exmaple, you can	159	IF you try out these expressions, you might suffer from some sluggishness,
121	tile the image to fill the whole window, instead of resizing it:	160	because each time the terminal is resized, it loads the PNG image again
		161	and scales it. Scaling is usually fast (and unavoidable), but loading the
		162	image can be quite time consuming. This is where C<keep> comes in handy:
122		163
		164	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		165
		166	The C<keep> operator executes all the statements inside the braces only
		167	once, or when it thinks the outcome might change. In other cases it
		168	returns the last value computed by the brace block.
		169
		170	This means that the C<load> is only executed once, which makes it much
		171	faster, but also means that more memory is being used, because the loaded
		172	image must be kept in memory at all times. In this expression, the
		173	trade-off is likely worth it.
		174
		175	But back to effects: Other effects than scaling are also readily
		176	available, for example, you can tile the image to fill the whole window,
		177	instead of resizing it:
		178
123	tile load "$HOME/mypic.png"	179	tile keep { load "$HOME/mypic.png" }
124		180
125	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator	181	In fact, images returned by C<load> are in C<tile> mode by default, so the
126	is kind of superfluous.	182	C<tile> operator is kind of superfluous.
127		183
128	Another common effect is to mirror the image, so that the same edges touch:	184	Another common effect is to mirror the image, so that the same edges
		185	touch:
129		186
130	mirror load "$HOME/mypic.png"	187	mirror keep { load "$HOME/mypic.png" }
131		188
132	This is also a typical background expression:	189	Another common background expression is:
133		190
134	rootalign root	191	rootalign root
135		192
136	It first takes a snapshot of the screen background image, and then	193	This one first takes a snapshot of the screen background image, and then
137	moves it to the upper left corner of the screen - the result is	194	moves it to the upper left corner of the screen (as opposed to the upper
138	pseudo-transparency, as the image seems to be static while the window is	195	left corner of the terminal window)- the result is pseudo-transparency:
139	moved around.	196	the image seems to be static while the window is moved around.
140		197
141	=head2 CYCLES AND CACHING	198	=head2 COLOUR SPECIFICATIONS
142		199
143	As has been mentioned before, the expression might be evaluated multiple	200	Whenever an operator expects a "colour", then this can be specified in one
144	times. Each time the expression is reevaluated, a new cycle is said to	201	of two ways: Either as string with an X11 colour specification, such as:
145	have begun. Many operators cache their results till the next cycle.
146		202
147	For example, the C<load> operator keeps a copy of the image. If it is	203	"red" # named colour
148	asked to load the same image on the next cycle it will not load it again,	204	"#f00" # simple rgb
149	but return the cached copy.	205	"[50]red" # red with 50% alpha
		206	"TekHVC:300/50/50" # anything goes
150		207
151	This only works for one cycle though, so as long as you load the same	208	OR as an array reference with one, three or four components:
152	image every time, it will always be cached, but when you load a different
153	image, it will forget about the first one.
154		209
155	This allows you to either speed things up by keeping multiple images in	210	[0.5] # 50% gray, 100% alpha
156	memory, or comserve memory by loading images more often.	211	[0.5, 0, 0] # dark red, no green or blur, 100% alpha
		212	[0.5, 0, 0, 0.7] # same with explicit 70% alpha
157		213
158	For example, you can keep two images in memory and use a random one like	214	=head2 CACHING AND SENSITIVITY
159	this:
160		215
161	my $img1 = load "img1.png";	216	Since some operations (such as C<load> and C<blur>) can take a long time,
162	my $img2 = load "img2.png";	217	caching results can be very important for a smooth operation. Caching can
163	(0.5 > rand) ? $img1 : $img2	218	also be useful to reduce memory usage, though, for example, when an image
		219	is cached by C<load>, it could be shared by multiple terminal windows
		220	running inside urxvtd.
164		221
165	Since both images are "loaded" every time the expression is evaluated,	222	=head3 C<keep { ... }> caching
166	they are always kept in memory. Contrast this version:
167		223
168	my $path1 = "img1.png";	224	The most important way to cache expensive operations is to use C<keep {
169	my $path2 = "img2.png";	225	... }>. The C<keep> operator takes a block of multiple statements enclosed
170	load ((0.5 > rand) ? $path1 : $path2)	226	by C<{}> and keeps the return value in memory.
171		227
172	Here, a path is selected randomly, and load is only called for one image,	228	An expression can be "sensitive" to various external events, such as
173	so keeps only one image in memory. If, on the next evaluation, luck	229	scaling or moving the window, root background changes and timers. Simply
174	decides to use the other path, then it will have to load that image again.	230	using an expression (such as C<scale> without parameters) that depends on
		231	certain changing values (called "variables"), or using those variables
		232	directly, will make an expression sensitive to these events - for example,
		233	using C<scale> or C<TW> will make the expression sensitive to the terminal
		234	size, and thus to resizing events.
		235
		236	When such an event happens, C<keep> will automatically trigger a
		237	reevaluation of the whole expression with the new value of the expression.
		238
		239	C<keep> is most useful for expensive operations, such as C<blur>:
		240
		241	rootalign keep { blur 20, root }
		242
		243	This makes a blurred copy of the root background once, and on subsequent
		244	calls, just root-aligns it. Since C<blur> is usually quite slow and
		245	C<rootalign> is quite fast, this trades extra memory (for the cached
		246	blurred pixmap) with speed (blur only needs to be redone when root
		247	changes).
		248
		249	=head3 C<load> caching
		250
		251	The C<load> operator itself does not keep images in memory, but as long as
		252	the image is still in memory, C<load> will use the in-memory image instead
		253	of loading it freshly from disk.
		254
		255	That means that this expression:
		256
		257	keep { load "$HOME/path..." }
		258
		259	Not only caches the image in memory, other terminal instances that try to
		260	C<load> it can reuse that in-memory copy.
175		261
176	=head1 REFERENCE	262	=head1 REFERENCE
177		263
178	=head2 COMMAND LINE SWITCHES	264	=head2 COMMAND LINE SWITCHES
179		265
180	=over 4	266	=over
181		267
182	=item --background-expr perl-expression	268	=item --background-expr perl-expression
183		269
184	Specifies the Perl expression to evaluate.	270	Specifies the Perl expression to evaluate.
185		271
…		…
191	Specifying this flag changes the behaviour, so that the image only	277	Specifying this flag changes the behaviour, so that the image only
192	replaces the background of the character area.	278	replaces the background of the character area.
193		279
194	=item --background-interval seconds	280	=item --background-interval seconds
195		281
196	Since some operations in the underlying XRender extension can effetively	282	Since some operations in the underlying XRender extension can effectively
197	freeze your X-server for prolonged time, this extension enforces a minimum	283	freeze your X-server for prolonged time, this extension enforces a minimum
198	time between updates, which is normally about 0.1 seconds.	284	time between updates, which is normally about 0.1 seconds.
199		285
200	If you want to do updates more often, you can decrease this safety	286	If you want to do updates more often, you can decrease this safety
201	interval with this switch.	287	interval with this switch.
202		288
203	=back	289	=back
204		290
205	=cut	291	=cut
206		292
207	our %_IMGCACHE;	293	our %_IMG_CACHE;
208	our $HOME;	294	our $HOME;
209	our ($self, $old, $new);	295	our ($self, $frame);
210	our ($x, $y, $w, $h);	296	our ($x, $y, $w, $h, $focus);
211		297
212	# enforce at least this interval between updates	298	# enforce at least this interval between updates
213	our $MIN_INTERVAL = 6/59.951;	299	our $MIN_INTERVAL = 6/59.951;
214		300
215	{	301	{
216	package urxvt::bgdsl; # background language	302	package urxvt::bgdsl; # background language
		303
		304	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
		305	sub FR_CACHE () { 1 } # cached values
		306	sub FR_AGAIN () { 2 } # what this expr is sensitive to
		307	sub FR_STATE () { 3 } # watchers etc.
217		308
218	use List::Util qw(min max sum shuffle);	309	use List::Util qw(min max sum shuffle);
219		310
220	=head2 PROVIDERS/GENERATORS	311	=head2 PROVIDERS/GENERATORS
221		312
222	These functions provide an image, by loading it from disk, grabbing it	313	These functions provide an image, by loading it from disk, grabbing it
223	from the root screen or by simply generating it. They are used as starting	314	from the root screen or by simply generating it. They are used as starting
224	points to get an image you can play with.	315	points to get an image you can play with.
225		316
226	=over 4	317	=over
227		318
228	=item load $path	319	=item load $path
229		320
230	Loads the image at the given C<$path>. The image is set to plane tiling	321	Loads the image at the given C<$path>. The image is set to plane tiling
231	mode.	322	mode.
232		323
233	Loaded images will be cached for one cycle.	324	If the image is already in memory (e.g. because another terminal instance
		325	uses it), then the in-memory copy is returned instead.
234		326
		327	=item load_uc $path
		328
		329	Load uncached - same as load, but does not cache the image, which means it
		330	is I<always> loaded from the filesystem again, even if another copy of it
		331	is in memory at the time.
		332
235	=cut	333	=cut
		334
		335	sub load_uc($) {
		336	$self->new_img_from_file ($_[0])
		337	}
236		338
237	sub load($) {	339	sub load($) {
238	my ($path) = @_;	340	my ($path) = @_;
239		341
240	$new->{load}{$path} = $old->{load}{$path} || $self->new_img_from_file ($path);	342	$_IMG_CACHE{$path} || do {
		343	my $img = load_uc $path;
		344	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		345	$img
		346	}
241	}	347	}
242		348
243	=item root	349	=item root
244		350
245	Returns the root window pixmap, that is, hopefully, the background image	351	Returns the root window pixmap, that is, hopefully, the background image
246	of your screen. The image is set to extend mode.	352	of your screen.
247		353
248	This function makes your expression root sensitive, that means it will be	354	This function makes your expression root sensitive, that means it will be
249	reevaluated when the bg image changes.	355	reevaluated when the bg image changes.
250		356
251	=cut	357	=cut
252		358
253	sub root() {	359	sub root() {
254	$new->{rootpmap_sensitive} = 1;	360	$frame->[FR_AGAIN]{rootpmap} = 1;
255	die "root op not supported, exg, we need you";	361	$self->new_img_from_root
256	}	362	}
257		363
258	=item solid $colour	364	=item solid $colour
259		365
260	=item solid $width, $height, $colour	366	=item solid $width, $height, $colour
…		…
268	=cut	374	=cut
269		375
270	sub solid($;$$) {	376	sub solid($;$$) {
271	my $colour = pop;	377	my $colour = pop;
272		378
273	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] || 1, $_[1] || 1);	379	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] || 1, $_[1] || 1);
274	$img->fill ($colour);	380	$img->fill ($colour);
275	$img	381	$img
276	}	382	}
277		383
278	=item clone $img	384	=item clone $img
…		…
284		390
285	sub clone($) {	391	sub clone($) {
286	$_[0]->clone	392	$_[0]->clone
287	}	393	}
288		394
		395	=item merge $img ...
		396
		397	Takes any number of images and merges them together, creating a single
		398	image containing them all. The tiling mode of the first image is used as
		399	the tiling mode of the resulting image.
		400
		401	This function is called automatically when an expression returns multiple
		402	images.
		403
		404	=cut
		405
		406	sub merge(@) {
		407	return $_[0] unless $#_;
		408
		409	# rather annoyingly clumsy, but optimisation is for another time
		410
		411	my $x0 = +1e9;
		412	my $y0 = +1e9;
		413	my $x1 = -1e9;
		414	my $y1 = -1e9;
		415
		416	for (@_) {
		417	my ($x, $y, $w, $h) = $_->geometry;
		418
		419	$x0 = $x if $x0 > $x;
		420	$y0 = $y if $y0 > $y;
		421
		422	$x += $w;
		423	$y += $h;
		424
		425	$x1 = $x if $x1 < $x;
		426	$y1 = $y if $y1 < $y;
		427	}
		428
		429	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		430	$base->repeat_mode ($_[0]->repeat_mode);
		431	$base->fill ([0, 0, 0, 0]);
		432
		433	$base->draw ($_)
		434	for @_;
		435
		436	$base
		437	}
		438
289	=back	439	=back
290		440
291	=head2 TILING MODES	441	=head2 TILING MODES
292		442
293	The following operators modify the tiling mode of an image, that is, the	443	The following operators modify the tiling mode of an image, that is, the
294	way that pixels outside the image area are painted when the image is used.	444	way that pixels outside the image area are painted when the image is used.
295		445
296	=over 4	446	=over
297		447
298	=item tile $img	448	=item tile $img
299		449
300	Tiles the whole plane with the image and returns this new image - or in	450	Tiles the whole plane with the image and returns this new image - or in
301	other words, it returns a copy of the image in plane tiling mode.	451	other words, it returns a copy of the image in plane tiling mode.
…		…
324	become transparent. This mode is most useful when you want to place an	474	become transparent. This mode is most useful when you want to place an
325	image over another image or the background colour while leaving all	475	image over another image or the background colour while leaving all
326	background pixels outside the image unchanged.	476	background pixels outside the image unchanged.
327		477
328	Example: load an image and display it in the upper left corner. The rest	478	Example: load an image and display it in the upper left corner. The rest
329	of the space is left "empty" (transparent or wahtever your compisotr does	479	of the space is left "empty" (transparent or whatever your compositor does
330	in alpha mode, else background colour).	480	in alpha mode, else background colour).
331		481
332	pad load "mybg.png"	482	pad load "mybg.png"
333		483
334	=item extend $img	484	=item extend $img
335		485
336	Extends the image over the whole plane, using the closest pixel in the	486	Extends the image over the whole plane, using the closest pixel in the
337	area outside the image. This mode is mostly useful when you more complex	487	area outside the image. This mode is mostly useful when you use more complex
338	filtering operations and want the pixels outside the image to have the	488	filtering operations and want the pixels outside the image to have the
339	same values as the pixels near the edge.	489	same values as the pixels near the edge.
340		490
341	Example: just for curiosity, how does this pixel extension stuff work?	491	Example: just for curiosity, how does this pixel extension stuff work?
342		492
…		…
376	dimensions. They are not (Perl-) variables, they just return stuff that	526	dimensions. They are not (Perl-) variables, they just return stuff that
377	varies. Most of them make your expression sensitive to some events, for	527	varies. Most of them make your expression sensitive to some events, for
378	example using C<TW> (terminal width) means your expression is evaluated	528	example using C<TW> (terminal width) means your expression is evaluated
379	again when the terminal is resized.	529	again when the terminal is resized.
380		530
381	=over 4	531	=over
382		532
383	=item TX	533	=item TX
384		534
385	=item TY	535	=item TY
386		536
387	Return the X and Y coordinates of the terminal window (the terminal	537	Return the X and Y coordinates of the terminal window (the terminal
388	window is the full window by default, and the character area only when in	538	window is the full window by default, and the character area only when in
389	border-respect mode).	539	border-respect mode).
390		540
391	Using these functions make your expression sensitive to window moves.	541	Using these functions makes your expression sensitive to window moves.
392		542
393	These functions are mainly useful to align images to the root window.	543	These functions are mainly useful to align images to the root window.
394		544
395	Example: load an image and align it so it looks as if anchored to the	545	Example: load an image and align it so it looks as if anchored to the
396	background.	546	background (that's exactly what C<rootalign> does btw.):
397		547
398	move -TX, -TY, load "mybg.png"	548	move -TX, -TY, keep { load "mybg.png" }
399		549
400	=item TW	550	=item TW
		551
		552	=item TH
401		553
402	Return the width (C<TW>) and height (C<TH>) of the terminal window (the	554	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
403	terminal window is the full window by default, and the character area only	555	terminal window is the full window by default, and the character area only
404	when in border-respect mode).	556	when in border-respect mode).
405		557
406	Using these functions make your expression sensitive to window resizes.	558	Using these functions makes your expression sensitive to window resizes.
407		559
408	These functions are mainly useful to scale images, or to clip images to	560	These functions are mainly useful to scale images, or to clip images to
409	the window size to conserve memory.	561	the window size to conserve memory.
410		562
411	Example: take the screen background, clip it to the window size, blur it a	563	Example: take the screen background, clip it to the window size, blur it a
412	bit, align it to the window position and use it as background.	564	bit, align it to the window position and use it as background.
413		565
414	clip move -TX, -TY, blur 5, root	566	clip move -TX, -TY, keep { blur 5, root }
415		567
416	=cut	568	=item FOCUS
417		569
418	sub TX() { $new->{position_sensitive} = 1; $x }	570	Returns a boolean indicating whether the terminal window has keyboard
419	sub TY() { $new->{position_sensitive} = 1; $y }	571	focus, in which case it returns true.
420	sub TW() { $new->{size_sensitive} = 1; $w }	572
421	sub TH() { $new->{size_sensitive} = 1; $h }	573	Using this function makes your expression sensitive to focus changes.
		574
		575	A common use case is to fade the background image when the terminal loses
		576	focus, often together with the C<-fade> command line option. In fact,
		577	there is a special function for just that use case: C<focus_fade>.
		578
		579	Example: use two entirely different background images, depending on
		580	whether the window has focus.
		581
		582	FOCUS ? keep { load "has_focus.jpg" } : keep { load "no_focus.jpg" }
		583
		584	=cut
		585
		586	sub TX () { $frame->[FR_AGAIN]{position} = 1; $x }
		587	sub TY () { $frame->[FR_AGAIN]{position} = 1; $y }
		588	sub TW () { $frame->[FR_AGAIN]{size} = 1; $w }
		589	sub TH () { $frame->[FR_AGAIN]{size} = 1; $h }
		590	sub FOCUS() { $frame->[FR_AGAIN]{focus} = 1; $focus }
422		591
423	=item now	592	=item now
424		593
425	Returns the current time as (fractional) seconds since the epoch.	594	Returns the current time as (fractional) seconds since the epoch.
426		595
…		…
433	C<$seconds> seconds.	602	C<$seconds> seconds.
434		603
435	Example: load some image and rotate it according to the time of day (as if it were	604	Example: load some image and rotate it according to the time of day (as if it were
436	the hour pointer of a clock). Update this image every minute.	605	the hour pointer of a clock). Update this image every minute.
437		606
		607	again 60;
438	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"	608	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
439		609
440	=item counter $seconds	610	=item counter $seconds
441		611
442	Like C<again>, but also returns an increasing counter value, starting at	612	Like C<again>, but also returns an increasing counter value, starting at
443	0, which might be useful for some simple animation effects.	613	0, which might be useful for some simple animation effects.
…		…
445	=cut	615	=cut
446		616
447	sub now() { urxvt::NOW }	617	sub now() { urxvt::NOW }
448		618
449	sub again($) {	619	sub again($) {
450	$new->{again} = $_[0];	620	$frame->[FR_AGAIN]{time} = $_[0];
451	}	621	}
452		622
453	sub counter($) {	623	sub counter($) {
454	$new->{again} = $_[0];	624	$frame->[FR_AGAIN]{time} = $_[0];
455	$self->{counter} + 0	625	$frame->[FR_STATE]{counter} + 0
456	}	626	}
457		627
458	=back	628	=back
459		629
460	=head2 SHAPE CHANGING OPERATORS	630	=head2 SHAPE CHANGING OPERATORS
461		631
462	The following operators modify the shape, size or position of the image.	632	The following operators modify the shape, size or position of the image.
463		633
464	=over 4	634	=over
465		635
466	=item clip $img	636	=item clip $img
467		637
468	=item clip $width, $height, $img	638	=item clip $width, $height, $img
469		639
…		…
472	Clips an image to the given rectangle. If the rectangle is outside the	642	Clips an image to the given rectangle. If the rectangle is outside the
473	image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is	643	image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is
474	larger than the image, then the tiling mode defines how the extra pixels	644	larger than the image, then the tiling mode defines how the extra pixels
475	will be filled.	645	will be filled.
476		646
477	If C<$x> an C<$y> are missing, then C<0> is assumed for both.	647	If C<$x> and C<$y> are missing, then C<0> is assumed for both.
478		648
479	If C<$width> and C<$height> are missing, then the window size will be	649	If C<$width> and C<$height> are missing, then the window size will be
480	assumed.	650	assumed.
481		651
482	Example: load an image, blur it, and clip it to the window size to save	652	Example: load an image, blur it, and clip it to the window size to save
483	memory.	653	memory.
484		654
485	clip blur 10, load "mybg.png"	655	clip keep { blur 10, load "mybg.png" }
486		656
487	=cut	657	=cut
488		658
489	sub clip($;$$;$$) {	659	sub clip($;$$;$$) {
490	my $img = pop;	660	my $img = pop;
…		…
500	=item scale $width_factor, $height_factor, $img	670	=item scale $width_factor, $height_factor, $img
501		671
502	Scales the image by the given factors in horizontal	672	Scales the image by the given factors in horizontal
503	(C<$width>) and vertical (C<$height>) direction.	673	(C<$width>) and vertical (C<$height>) direction.
504		674
505	If only one factor is give, it is used for both directions.	675	If only one factor is given, it is used for both directions.
506		676
507	If no factors are given, scales the image to the window size without	677	If no factors are given, scales the image to the window size without
508	keeping aspect.	678	keeping aspect.
509		679
510	=item resize $width, $height, $img	680	=item resize $width, $height, $img
…		…
584	the terminal window (or the box specified by C<$width> and C<$height> if	754	the terminal window (or the box specified by C<$width> and C<$height> if
585	given).	755	given).
586		756
587	Example: load an image and center it.	757	Example: load an image and center it.
588		758
589	center pad load "mybg.png"	759	center keep { pad load "mybg.png" }
590		760
591	=item rootalign $img	761	=item rootalign $img
592		762
593	Moves the image so that it appears glued to the screen as opposed to the	763	Moves the image so that it appears glued to the screen as opposed to the
594	window. This gives the illusion of a larger area behind the window. It is	764	window. This gives the illusion of a larger area behind the window. It is
595	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	765	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
596	top left of the screen.	766	top left of the screen.
597		767
598	Example: load a background image, put it in mirror mode and root align it.	768	Example: load a background image, put it in mirror mode and root align it.
599		769
600	rootalign mirror load "mybg.png"	770	rootalign keep { mirror load "mybg.png" }
601		771
602	Example: take the screen background and align it, giving the illusion of	772	Example: take the screen background and align it, giving the illusion of
603	transparency as long as the window isn't in front of other windows.	773	transparency as long as the window isn't in front of other windows.
604		774
605	rootalign root	775	rootalign root
…		…
630		800
631	sub rootalign($) {	801	sub rootalign($) {
632	move -TX, -TY, $_[0]	802	move -TX, -TY, $_[0]
633	}	803	}
634		804
		805	=item rotate $center_x, $center_y, $degrees, $img
		806
		807	Rotates the image clockwise by C<$degrees> degrees, around the point at
		808	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		809
		810	Example: rotate the image by 90 degrees around its center.
		811
		812	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		813
		814	=cut
		815
		816	sub rotate($$$$) {
		817	my $img = pop;
		818	$img->rotate (
		819	$_[0] * ($img->w + $img->x),
		820	$_[1] * ($img->h + $img->y),
		821	$_[2] * (3.14159265 / 180),
		822	)
		823	}
		824
635	=back	825	=back
636		826
637	=head2 COLOUR MODIFICATIONS	827	=head2 COLOUR MODIFICATIONS
638		828
639	The following operators change the pixels of the image.	829	The following operators change the pixels of the image.
640		830
641	=over 4	831	=over
		832
		833	=item tint $color, $img
		834
		835	Tints the image in the given colour.
		836
		837	Example: tint the image red.
		838
		839	tint "red", load "rgb.png"
		840
		841	Example: the same, but specify the colour by component.
		842
		843	tint [1, 0, 0], load "rgb.png"
		844
		845	=cut
		846
		847	sub tint($$) {
		848	$_[1]->tint ($_[0])
		849	}
		850
		851	=item shade $factor, $img
		852
		853	Shade the image by the given factor.
		854
		855	=cut
		856
		857	sub shade($$) {
		858	$_[1]->shade ($_[0])
		859	}
642		860
643	=item contrast $factor, $img	861	=item contrast $factor, $img
644		862
645	=item contrast $r, $g, $b, $img	863	=item contrast $r, $g, $b, $img
646		864
…		…
673		891
674	Values less than 0 reduce brightness, while values larger than 0 increase	892	Values less than 0 reduce brightness, while values larger than 0 increase
675	it. Useful range is from -1 to 1 - the former results in a black, the	893	it. Useful range is from -1 to 1 - the former results in a black, the
676	latter in a white picture.	894	latter in a white picture.
677		895
678	Due to idiosynchrasies in the underlying XRender extension, biases less	896	Due to idiosyncrasies in the underlying XRender extension, biases less
679	than zero can be I<very> slow.	897	than zero can be I<very> slow.
		898
		899	You can also try the experimental(!) C<muladd> operator.
680		900
681	=cut	901	=cut
682		902
683	sub contrast($$;$$;$) {	903	sub contrast($$;$$;$) {
684	my $img = pop;	904	my $img = pop;
…		…
700	$a = 1 if @_ < 4;	920	$a = 1 if @_ < 4;
701		921
702	$img = $img->clone;	922	$img = $img->clone;
703	$img->brightness ($r, $g, $b, $a);	923	$img->brightness ($r, $g, $b, $a);
704	$img	924	$img
		925	}
		926
		927	=item muladd $mul, $add, $img # EXPERIMENTAL
		928
		929	First multiplies the pixels by C<$mul>, then adds C<$add>. This can be used
		930	to implement brightness and contrast at the same time, with a wider value
		931	range than contrast and brightness operators.
		932
		933	Due to numerous bugs in XRender implementations, it can also introduce a
		934	number of visual artifacts.
		935
		936	Example: increase contrast by a factor of C<$c> without changing image
		937	brightness too much.
		938
		939	muladd $c, (1 - $c) * 0.5, $img
		940
		941	=cut
		942
		943	sub muladd($$$) {
		944	$_[2]->muladd ($_[0], $_[1])
705	}	945	}
706		946
707	=item blur $radius, $img	947	=item blur $radius, $img
708		948
709	=item blur $radius_horz, $radius_vert, $img	949	=item blur $radius_horz, $radius_vert, $img
…		…
721	sub blur($$;$) {	961	sub blur($$;$) {
722	my $img = pop;	962	my $img = pop;
723	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	963	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
724	}	964	}
725		965
726	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees	966	=item focus_fade $img
727		967
728	Rotates the image by C<$degrees> degrees, counter-clockwise, around the	968	=item focus_fade $factor, $img
729	pointer at C<$center_x> and C<$center_y> (specified as factor of image
730	width/height), generating a new image with width C<$new_width> and height
731	C<$new_height>.
732		969
733	#TODO# new width, height, maybe more operators?	970	=item focus_fade $factor, $color, $img
734		971
735	Example: rotate the image by 90 degrees	972	Fades the image by the given factor (and colour) when focus is lost (the
		973	same as the C<-fade>/C<-fadecolor> command line options, which also supply
		974	the default values for C<factor> and C<$color>. Unlike with C<-fade>, the
		975	C<$factor> is a real value, not a percentage value (that is, 0..1, not
		976	0..100).
736		977
737	=cut	978	Example: do the right thing when focus fading is requested.
738		979
739	sub rotate($$$$$$) {	980	focus_fade load "mybg.jpg";
		981
		982	=cut
		983
		984	sub focus_fade($;$$) {
740	my $img = pop;	985	my $img = pop;
741	$img->rotate (	986
742	$_[0],	987	return $img
743	$_[1],	988	if FOCUS;
744	$_[2] * $img->w,	989
745	$_[3] * $img->h,	990	my $fade = @_ >= 1 ? $_[0] : defined $self->resource ("fade") ? $self->resource ("fade") * 0.01 : 0;
746	$_[4] * (3.14159265 / 180),	991	my $color = @_ >= 2 ? $_[1] : $self->resource ("color+" . &urxvt::Color_fade ()); # Color_fade not always available
747	)	992
		993	$img = $img->tint ($color) if $color ne "rgb:00/00/00";
		994	$img = $img->muladd (1 - $fade, 0) if $fade;
		995
		996	$img
748	}	997	}
749		998
750	=back	999	=back
751		1000
		1001	=head2 OTHER STUFF
		1002
		1003	Anything that didn't fit any of the other categories, even after applying
		1004	force and closing our eyes.
		1005
		1006	=over
		1007
		1008	=item keep { ... }
		1009
		1010	This operator takes a code block as argument, that is, one or more
		1011	statements enclosed by braces.
		1012
		1013	The trick is that this code block is only evaluated when the outcome
		1014	changes - on other calls the C<keep> simply returns the image it computed
		1015	previously (yes, it should only be used with images). Or in other words,
		1016	C<keep> I<caches> the result of the code block so it doesn't need to be
		1017	computed again.
		1018
		1019	This can be extremely useful to avoid redoing slow operations - for
		1020	example, if your background expression takes the root background, blurs it
		1021	and then root-aligns it it would have to blur the root background on every
		1022	window move or resize.
		1023
		1024	Another example is C<load>, which can be quite slow.
		1025
		1026	In fact, urxvt itself encloses the whole expression in some kind of
		1027	C<keep> block so it only is reevaluated as required.
		1028
		1029	Putting the blur into a C<keep> block will make sure the blur is only done
		1030	once, while the C<rootalign> is still done each time the window moves.
		1031
		1032	rootalign keep { blur 10, root }
		1033
		1034	This leaves the question of how to force reevaluation of the block,
		1035	in case the root background changes: If expression inside the block
		1036	is sensitive to some event (root background changes, window geometry
		1037	changes), then it will be reevaluated automatically as needed.
		1038
		1039	=back
		1040
		1041	=head1 OLD BACKGROUND IMAGE SETTINGS
		1042
		1043	This extension also provides support for the old options/resources and
		1044	OSC sequences for setting a background image. These settings are
		1045	B<deprecated> and will be removed in future versions.
		1046
		1047	=head2 OPTIONS AND RESOURCES
		1048
		1049	=over
		1050
		1051	=item B<-pixmap> I<file[;oplist]>
		1052
		1053	=item B<backgroundPixmap:> I<file[;oplist]>
		1054
		1055	Use the specified image file as the window's background and also
		1056	optionally specify a colon separated list of operations to modify it.
		1057	Note that you may need to quote the C<;> character when using the
		1058	command line option, as C<;> is usually a metacharacter in shells.
		1059	Supported operations are:
		1060
		1061	=over
		1062
		1063	=item B<WxH+X+Y>
		1064
		1065	sets scale and position. B<"W" / "H"> specify the horizontal/vertical
		1066	scale (percent), and B<"X" / "Y"> locate the image centre (percent). A
		1067	scale of 0 disables scaling.
		1068
		1069	=item B<op=tile>
		1070
		1071	enables tiling
		1072
		1073	=item B<op=keep-aspect>
		1074
		1075	maintain the image aspect ratio when scaling
		1076
		1077	=item B<op=root-align>
		1078
		1079	use the position of the terminal window relative to the root window as
		1080	the image offset, simulating a root window background
		1081
		1082	=back
		1083
		1084	The default scale and position setting is C<100x100+50+50>.
		1085	Alternatively, a predefined set of templates can be used to achieve
		1086	the most common setups:
		1087
		1088	=over
		1089
		1090	=item B<style=tiled>
		1091
		1092	the image is tiled with no scaling. Equivalent to 0x0+0+0:op=tile
		1093
		1094	=item B<style=aspect-stretched>
		1095
		1096	the image is scaled to fill the whole window maintaining the aspect
		1097	ratio and centered. Equivalent to 100x100+50+50:op=keep-aspect
		1098
		1099	=item B<style=stretched>
		1100
		1101	the image is scaled to fill the whole window. Equivalent to 100x100
		1102
		1103	=item B<style=centered>
		1104
		1105	the image is centered with no scaling. Equivalent to 0x0+50+50
		1106
		1107	=item B<style=root-tiled>
		1108
		1109	the image is tiled with no scaling and using 'root' positioning.
		1110	Equivalent to 0x0:op=tile:op=root-align
		1111
		1112	=back
		1113
		1114	If multiple templates are specified the last one wins. Note that a
		1115	template overrides all the scale, position and operations settings.
		1116
		1117	If used in conjunction with pseudo-transparency, the specified image
		1118	will be blended over the transparent background using alpha-blending.
		1119
		1120	=item B<-tr>|B<+tr>
		1121
		1122	=item B<transparent:> I<boolean>
		1123
		1124	Turn on/off pseudo-transparency by using the root pixmap as background.
		1125
		1126	=item B<-tint> I<colour>
		1127
		1128	=item B<tintColor:> I<colour>
		1129
		1130	Tint the transparent background with the given colour. Note that a
		1131	black tint yields a completely black image while a white tint yields
		1132	the image unchanged.
		1133
		1134	=item B<-sh> I<number>
		1135
		1136	=item B<shading:> I<number>
		1137
		1138	Darken (0 .. 99) or lighten (101 .. 200) the transparent background.
		1139	A value of 100 means no shading.
		1140
		1141	=item B<-blr> I<HxV>
		1142
		1143	=item B<blurRadius:> I<HxV>
		1144
		1145	Apply gaussian blur with the specified radius to the transparent
		1146	background. If a single number is specified, the vertical and
		1147	horizontal radii are considered to be the same. Setting one of the
		1148	radii to 1 and the other to a large number creates interesting effects
		1149	on some backgrounds. The maximum radius value is 128. An horizontal or
		1150	vertical radius of 0 disables blurring.
		1151
		1152	=back
		1153
		1154	=head2 OSC sequences
		1155
		1156	This extension will react to the following OSC sequences. Note that
		1157	this extension will not be autoloaded when these are used currently,
		1158	so to make urxvt recognize them, you have to enable the C<background>
		1159	extension. One way to achieve that is to use the C<--background-expr ''>
		1160	command line argument or by specifying an empty C<URxvt.background.expr:>>
		1161	resource.
		1162
		1163	=over
		1164
		1165	=item B<< C<ESC ] 705 ; Pt ST> >> Change transparent background tint colour to B<< C<Pt> >>.
		1166
		1167	=item B<< C<ESC ] 20 ; Pt ST> >> Change/Query background image
		1168	parameters: the value of B<< C<Pt> >> can be one of the following
		1169	commands:
		1170
		1171	=over
		1172
		1173	=item B<< C<?> >>
		1174
		1175	display scale and position in the title
		1176
		1177	=item B<< C<;WxH+X+Y> >>
		1178
		1179	change scale and/or position
		1180
		1181	=item B<< C<FILE;WxH+X+Y> >>
		1182
		1183	change background image
		1184
		1185	=back
		1186
		1187	=cut
		1188
		1189	sub keep(&) {
		1190	my $id = $_[0]+0;
		1191
		1192	local $frame = $self->{frame_cache}{$id} ||= [$frame];
		1193
		1194	unless ($frame->[FR_CACHE]) {
		1195	$frame->[FR_CACHE] = [ $_[0]() ];
		1196
		1197	my $self = $self;
		1198	my $frame = $frame;
		1199	Scalar::Util::weaken $frame;
		1200	$self->compile_frame ($frame, sub {
		1201	# clear this frame cache, also for all parents
		1202	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		1203	undef $frame->[FR_CACHE];
		1204	}
		1205
		1206	$self->recalculate;
		1207	});
		1208	};
		1209
		1210	# in scalar context we always return the first original result, which
		1211	# is not quite how perl works.
		1212	wantarray
		1213	? @{ $frame->[FR_CACHE] }
		1214	: $frame->[FR_CACHE][0]
		1215	}
		1216
		1217	# sub keep_clear() {
		1218	# delete $self->{frame_cache};
		1219	# }
		1220
		1221	=back
		1222
752	=cut	1223	=cut
753		1224
754	}	1225	}
755		1226
756	sub parse_expr {	1227	sub parse_expr {
757	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	1228	my ($expr) = @_;
		1229
		1230	# an empty expression is valid and represents the default background
		1231	if ($expr !~ /\S/) {
		1232	$expr = sub {
		1233	undef
		1234	};
		1235	} else {
		1236	$expr = eval
		1237	"sub {\n"
		1238	. "package urxvt::bgdsl;\n"
		1239	. "#line 0 'background expression'\n"
		1240	. "$expr\n"
		1241	. "}";
758	die if $@;	1242	die if $@;
		1243	}
		1244
759	$expr	1245	$expr
760	}	1246	}
761		1247
762	# compiles a parsed expression	1248	# compiles a parsed expression
763	sub set_expr {	1249	sub set_expr {
764	my ($self, $expr) = @_;	1250	my ($self, $expr) = @_;
765		1251
		1252	$self->{root} = []; # the outermost frame
766	$self->{expr} = $expr;	1253	$self->{expr} = $expr;
767	$self->recalculate;	1254	$self->recalculate;
		1255	}
		1256
		1257	# takes a hash of sensitivity indicators and installs watchers
		1258	sub compile_frame {
		1259	my ($self, $frame, $cb) = @_;
		1260
		1261	my $state = $frame->[urxvt::bgdsl::FR_STATE] ||= {};
		1262	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		1263
		1264	# don't keep stuff alive
		1265	Scalar::Util::weaken $state;
		1266
		1267	if ($again->{nested}) {
		1268	$state->{nested} = 1;
		1269	} else {
		1270	delete $state->{nested};
		1271	}
		1272
		1273	if (my $interval = $again->{time}) {
		1274	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		1275	if $state->{time}[0] != $interval;
		1276
		1277	# callback *might* have changed, although we could just rule that out
		1278	$state->{time}[1]->cb (sub {
		1279	++$state->{counter};
		1280	$cb->();
		1281	});
		1282	} else {
		1283	delete $state->{time};
		1284	}
		1285
		1286	if ($again->{position}) {
		1287	$state->{position} = $self->on (position_change => $cb);
		1288	} else {
		1289	delete $state->{position};
		1290	}
		1291
		1292	if ($again->{size}) {
		1293	$state->{size} = $self->on (size_change => $cb);
		1294	} else {
		1295	delete $state->{size};
		1296	}
		1297
		1298	if ($again->{rootpmap}) {
		1299	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		1300	} else {
		1301	delete $state->{rootpmap};
		1302	}
		1303
		1304	if ($again->{focus}) {
		1305	$state->{focus} = $self->on (focus_in => $cb, focus_out => $cb);
		1306	} else {
		1307	delete $state->{focus};
		1308	}
768	}	1309	}
769		1310
770	# evaluate the current bg expression	1311	# evaluate the current bg expression
771	sub recalculate {	1312	sub recalculate {
772	my ($arg_self) = @_;	1313	my ($arg_self) = @_;
…		…
780	return;	1321	return;
781	}	1322	}
782		1323
783	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1324	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
784		1325
		1326	unless ($arg_self->has_render) {
		1327	warn "background extension needs RENDER extension 0.11 or higher, ignoring background-expr.\n";
		1328	return;
		1329	}
		1330
785	# set environment to evaluate user expression	1331	# set environment to evaluate user expression
786		1332
787	local $self = $arg_self;	1333	local $self = $arg_self;
788
789	local $HOME = $ENV{HOME};	1334	local $HOME = $ENV{HOME};
790	local $old = $self->{state};	1335	local $frame = $self->{root};
791	local $new = my $state = $self->{state} = {};
792		1336
793	($x, $y, $w, $h) =
794	$self->background_geometry ($self->{border});	1337	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
		1338	$focus = $self->focus;
795		1339
796	# evaluate user expression	1340	# evaluate user expression
797		1341
798	my $img = eval { $self->{expr}->() };	1342	my @img = eval { $self->{expr}->() };
799	warn $@ if $@;#d#	1343	die $@ if $@;
800	die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";	1344	die "background-expr did not return anything.\n" unless @img;
801		1345
802	$state->{size_sensitive} = 1	1346	if ($img[0]) {
		1347	die "background-expr: expected image(s), got something else.\n"
		1348	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
		1349
		1350	my $img = urxvt::bgdsl::merge @img;
		1351
		1352	$frame->[urxvt::bgdsl::FR_AGAIN]{size} = 1
803	if $img->repeat_mode != urxvt::RepeatNormal;	1353	if $img->repeat_mode != urxvt::RepeatNormal;
804		1354
805	# if the expression is sensitive to external events, prepare reevaluation then	1355	# if the expression is sensitive to external events, prepare reevaluation then
		1356	$self->compile_frame ($frame, sub { $arg_self->recalculate });
806		1357
807	my $repeat;	1358	# clear stuff we no longer need
808		1359
809	if (my $again = $state->{again}) {	1360	# unless (%{ $frame->[FR_STATE] }) {
810	$repeat = 1;	1361	# delete $self->{state};
811	my $self = $self;	1362	# delete $self->{expr};
812	$state->{timer} = $again == $old->{again}
813	? $old->{timer}
814	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
815	++$self->{counter};
816	$self->recalculate
817	});
818	}	1363	# }
819		1364
820	if (delete $state->{position_sensitive}) {	1365	# set background pixmap
821	$repeat = 1;	1366
822	$self->enable (position_change => sub { $_[0]->recalculate });	1367	$self->set_background ($img, $self->{border});
823	} else {	1368	} else {
824	$self->disable ("position_change");	1369	$self->clr_background;
825	}	1370	}
826		1371
827	if (delete $state->{size_sensitive}) {
828	$repeat = 1;
829	$self->enable (size_change => sub { $_[0]->recalculate });
830	} else {
831	$self->disable ("size_change");
832	}
833
834	if (delete $state->{rootpmap_sensitive}) {
835	$repeat = 1;
836	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
837	} else {
838	$self->disable ("rootpmap_change");
839	}
840
841	# clear stuff we no longer need
842
843	%$old = ();
844
845	unless ($repeat) {
846	delete $self->{state};
847	delete $self->{expr};
848	}
849
850	# set background pixmap
851
852	$self->set_background ($img, $self->{border});
853	$self->scr_recolour (0);	1372	$self->scr_recolor (0);
854	$self->want_refresh;	1373	$self->want_refresh;
855	}	1374	}
856		1375
		1376	sub old_bg_opts {
		1377	my ($self, $arg) = @_;
		1378
		1379	$arg or return;
		1380
		1381	my @str = split /;/, $arg;
		1382
		1383	return unless $str[0] or $self->{bg_opts}->{path};
		1384
		1385	my $bg_opts = $self->{bg_opts};
		1386
		1387	if ($str[0]) {
		1388	$bg_opts->{tile} = 0;
		1389	$bg_opts->{keep_aspect} = 0;
		1390	$bg_opts->{root_align} = 0;
		1391	$bg_opts->{h_scale} = $bg_opts->{v_scale} = 100;
		1392	$bg_opts->{h_align} = $bg_opts->{v_align} = 50;
		1393	$bg_opts->{path} = $str[0];
		1394	}
		1395
		1396	my @oplist = split /:/, $str[1];
		1397
		1398	for (@oplist) {
		1399	if (/style=tiled/i) {
		1400	$bg_opts->{tile} = 1;
		1401	$bg_opts->{keep_aspect} = 0;
		1402	$bg_opts->{root_align} = 0;
		1403	$bg_opts->{h_scale} = $bg_opts->{v_scale} = 0;
		1404	$bg_opts->{h_align} = $bg_opts->{v_align} = 0;
		1405	} elsif (/style=aspect-stretched/i) {
		1406	$bg_opts->{tile} = 0;
		1407	$bg_opts->{keep_aspect} = 1;
		1408	$bg_opts->{root_align} = 0;
		1409	$bg_opts->{h_scale} = $bg_opts->{v_scale} = 100;
		1410	$bg_opts->{h_align} = $bg_opts->{v_align} = 50;
		1411	} elsif (/style=stretched/i) {
		1412	$bg_opts->{tile} = 0;
		1413	$bg_opts->{keep_aspect} = 0;
		1414	$bg_opts->{root_align} = 0;
		1415	$bg_opts->{h_scale} = $bg_opts->{v_scale} = 100;
		1416	$bg_opts->{h_align} = $bg_opts->{v_align} = 50;
		1417	} elsif (/style=centered/i) {
		1418	$bg_opts->{tile} = 0;
		1419	$bg_opts->{keep_aspect} = 0;
		1420	$bg_opts->{root_align} = 0;
		1421	$bg_opts->{h_scale} = $bg_opts->{v_scale} = 0;
		1422	$bg_opts->{h_align} = $bg_opts->{v_align} = 50;
		1423	} elsif (/style=root-tiled/i) {
		1424	$bg_opts->{tile} = 1;
		1425	$bg_opts->{keep_aspect} = 0;
		1426	$bg_opts->{root_align} = 1;
		1427	$bg_opts->{h_scale} = $bg_opts->{v_scale} = 0;
		1428	$bg_opts->{h_align} = $bg_opts->{v_align} = 0;
		1429	} elsif (/op=tile/i) {
		1430	$bg_opts->{tile} = 1;
		1431	} elsif (/op=keep-aspect/i) {
		1432	$bg_opts->{keep_aspect} = 1;
		1433	} elsif (/op=root-align/i) {
		1434	$bg_opts->{root_align} = 1;
		1435	} elsif (/^ =? ([0-9]+)? (?:[xX] ([0-9]+))? ([+-][0-9]+)? ([+-][0-9]+)? $/x) {
		1436	my ($w, $h, $x, $y) = ($1, $2, $3, $4);
		1437
		1438	if ($str[0]) {
		1439	$w = $h unless defined $w;
		1440	$h = $w unless defined $h;
		1441	$y = $x unless defined $y;
		1442	}
		1443
		1444	$bg_opts->{h_scale} = $w if defined $w;
		1445	$bg_opts->{v_scale} = $h if defined $h;
		1446	$bg_opts->{h_align} = $x if defined $x;
		1447	$bg_opts->{v_align} = $y if defined $y;
		1448	}
		1449	}
		1450	}
		1451
		1452	# helper function, quote string as perl without allowing
		1453	# any code execution or other shenanigans.
		1454	sub q0 {
		1455	"qq\x00\Q$_[0]\E\x00"
		1456	}
		1457
		1458	sub old_bg_expr {
		1459	my ($self) = @_;
		1460
		1461	my $expr;
		1462
		1463	my $bg_opts = $self->{bg_opts};
		1464
		1465	if ($bg_opts->{root} =~ /^\s*(?:true|yes|on|1)\s*$/i) {
		1466	$expr .= "tile (";
		1467
		1468	my $shade = $bg_opts->{shade};
		1469
		1470	if ($shade) {
		1471	$shade = List::Util::min $shade, 200;
		1472	$shade = List::Util::max $shade, -100;
		1473	$shade = 200 - (100 + $shade) if $shade < 0;
		1474
		1475	$shade = $shade * 0.01 - 1;
		1476	$expr .= "shade $shade, ";
		1477	}
		1478
		1479	my $tint = $bg_opts->{tint};
		1480
		1481	if ($tint) {
		1482	$tint = q0 $tint;
		1483	$expr .= "tint $tint,";
		1484	}
		1485
		1486	my $blur = $bg_opts->{blur};
		1487
		1488	if ($blur and $blur =~ /^ =? ([0-9]+)? (?:[xX] ([0-9]+))? $/x) {
		1489	my $hr = defined $1 ? $1 : 1;
		1490	my $vr = defined $2 ? $2 : $hr;
		1491
		1492	if ($hr != 0 and $vr != 0) {
		1493	$expr .= "blur $hr, $vr, ";
		1494	}
		1495	}
		1496
		1497	$expr .= "rootalign root)";
		1498	}
		1499
		1500	if ($bg_opts->{path}) {
		1501	my $file_expr;
		1502	my $h_scale = $bg_opts->{h_scale} * 0.01;
		1503	my $v_scale = $bg_opts->{v_scale} * 0.01;
		1504	my $h_align = $bg_opts->{h_align} * 0.01;
		1505	my $v_align = $bg_opts->{v_align} * 0.01;
		1506
		1507	if (!$bg_opts->{tile}) {
		1508	$file_expr .= "pad (";
		1509	} else {
		1510	$file_expr .= "tile (";
		1511	}
		1512
		1513	if ($bg_opts->{root_align}) {
		1514	$file_expr .= "rootalign ";
		1515	} else {
		1516	$file_expr .= "align $h_align, $v_align, ";
		1517	}
		1518
		1519	if ($h_scale != 0 and $v_scale != 0) {
		1520	my $op = $bg_opts->{keep_aspect} ? "fit" : "resize";
		1521	$file_expr .= "$op TW * $h_scale, TH * $v_scale, ";
		1522	}
		1523
		1524	my $path = q0 $bg_opts->{path};
		1525
		1526	$file_expr .= "keep { load $path })";
		1527
		1528	if ($expr) {
		1529	$expr .= ", tint (\"[50]white\", $file_expr)";
		1530	} else {
		1531	$expr = $file_expr;
		1532	}
		1533	}
		1534
		1535	$expr
		1536	}
		1537
		1538	sub find_resource {
		1539	my ($self, $res, $opt) = @_;
		1540
		1541	my $v = $self->x_resource ($opt);
		1542	$v = $self->x_resource ($res) unless defined $v;
		1543
		1544	$v
		1545	}
		1546
		1547	sub parse_bgopts {
		1548	my ($self) = @_;
		1549
		1550	my $expr = $self->x_resource ("%.expr");
		1551
		1552	if (!$expr) {
		1553	$self->{bg_opts} = { h_scale => 100, v_scale => 100,
		1554	h_align => 50, v_align => 50 };
		1555
		1556	$self->{bg_opts}{shade} = $self->find_resource ("shading", "sh");
		1557	$self->{bg_opts}{tint} = $self->find_resource ("tintColor", "tint");
		1558	$self->{bg_opts}{blur} = $self->find_resource ("blurRadius", "blr");
		1559	$self->{bg_opts}{root} = $self->find_resource ("transparent", "tr");
		1560
		1561	$self->old_bg_opts ($self->find_resource ("backgroundPixmap", "pixmap"));
		1562	$expr = $self->old_bg_expr;
		1563	}
		1564
		1565	$self->set_expr (parse_expr $expr);
		1566	$self->{border} = $self->x_resource_boolean ("%.border");
		1567
		1568	$MIN_INTERVAL = $self->x_resource ("%.interval");
		1569	}
		1570
857	sub on_start {	1571	sub on_start {
858	my ($self) = @_;	1572	my ($self) = @_;
859		1573
860	my $expr = $self->x_resource ("%.expr")	1574	$self->parse_bgopts;
861	or return;
862
863	$self->has_render
864	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
865
866	$self->set_expr (parse_expr $expr);
867	$self->{border} = $self->x_resource_boolean ("%.border");
868
869	$MIN_INTERVAL = $self->x_resource ("%.interval");
870		1575
871	()	1576	()
872	}	1577	}
873		1578
		1579	sub on_osc_seq {
		1580	my ($self, $op, $arg) = @_;
		1581
		1582	$op eq "20" or $op eq "706"
		1583	or return;
		1584
		1585	$self->{bg_opts}
		1586	or $self->parse_bgopts;
		1587
		1588	if ($op eq "20") {
		1589	if ($arg eq "?") {
		1590	my $h_scale = $self->{bg_opts}{h_scale};
		1591	my $v_scale = $self->{bg_opts}{v_scale};
		1592	my $h_align = $self->{bg_opts}{h_align};
		1593	my $v_align = $self->{bg_opts}{v_align};
		1594	$self->cmd_parse ("\033]2;[${h_scale}x${v_scale}+${h_align}+${v_align}]\007");
		1595	} else {
		1596	$self->old_bg_opts ($arg);
		1597	my $expr = $self->old_bg_expr;
		1598	$self->set_expr (parse_expr $expr) if $expr;
		1599	}
		1600	} elsif ($op eq "705") {
		1601	$self->{bg_opts}{tint} = $arg;
		1602	my $expr = $self->old_bg_expr;
		1603	$self->set_expr (parse_expr $expr) if $expr;
		1604	}
		1605
		1606	1
		1607	}
		1608

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