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Revision 1.32 by sf-exg, Thu Jun 7 13:56:27 2012 UTC vs.
Revision 1.97 by root, Tue Sep 17 18:17:14 2019 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:%.enable:boolean:some boolean	4	#:META:RESOURCE:%.border:boolean:respect the terminal border
5	#:META:X_RESOURCE:%.extra.:value:extra config	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
6		16
7	our $EXPR;	17	=head1 NAME
8	#$EXPR = 'move W * 0.1, -H * 0.1, resize W * 0.5, H * 0.5, repeat_none load "opensource.png"';
9	$EXPR = 'move -TX, -TY, load "argb.png"';
10	#$EXPR = '
11	# rotate W, H, 50, 50, counter 1/59.95, repeat_mirror,
12	# clip X, Y, W, H, repeat_mirror,
13	# load "/root/pix/das_fette_schwein.jpg"
14	#';
15	#$EXPR = 'solid "red"';
16	#$EXPR = 'blur root, 10, 10'
17	#$EXPR = 'blur move (root, -x, -y), 5, 5'
18	#resize load "/root/pix/das_fette_schwein.jpg", w, h
19		18
20	use Safe;	19	background - manage terminal background
21		20
22	our ($bgdsl_self, $old, $new);	21	=head1 SYNOPSIS
		22
		23	urxvt --background-expr 'background expression'
		24	--background-border
		25	--background-interval seconds
		26
		27	=head1 QUICK AND DIRTY CHEAT SHEET
		28
		29	Just load a random jpeg image and tile the background with it without
		30	scaling or anything else:
		31
		32	load "/path/to/img.jpg"
		33
		34	The same, but use mirroring/reflection instead of tiling:
		35
		36	mirror load "/path/to/img.jpg"
		37
		38	Load an image and scale it to exactly fill the terminal window:
		39
		40	scale keep { load "/path/to/img.jpg" }
		41
		42	Implement pseudo-transparency by using a suitably-aligned root pixmap
		43	as window background:
		44
		45	rootalign root
		46
		47	Likewise, but keep a blurred copy:
		48
		49	rootalign keep { blur 10, root }
		50
		51	=head1 DESCRIPTION
		52
		53	This extension manages the terminal background by creating a picture that
		54	is behind the text, replacing the normal background colour.
		55
		56	It does so by evaluating a Perl expression that I<calculates> the image on
		57	the fly, for example, by grabbing the root background or loading a file.
		58
		59	While the full power of Perl is available, the operators have been design
		60	to be as simple as possible.
		61
		62	For example, to load an image and scale it to the window size, you would
		63	use:
		64
		65	urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
		66
		67	Or specified as a X resource:
		68
		69	URxvt.background.expr: scale keep { load "/path/to/mybg.png" }
		70
		71	=head1 THEORY OF OPERATION
		72
		73	At startup, just before the window is mapped for the first time, the
		74	expression is evaluated and must yield an image. The image is then
		75	extended as necessary to cover the whole terminal window, and is set as a
		76	background pixmap.
		77
		78	If the image contains an alpha channel, then it will be used as-is in
		79	visuals that support alpha channels (for example, for a compositing
		80	manager). In other visuals, the terminal background colour will be used to
		81	replace any transparency.
		82
		83	When the expression relies, directly or indirectly, on the window size,
		84	position, the root pixmap, or a timer, then it will be remembered. If not,
		85	then it will be removed.
		86
		87	If any of the parameters that the expression relies on changes (when the
		88	window is moved or resized, its position or size changes; when the root
		89	pixmap is replaced by another one the root background changes; or when the
		90	timer elapses), then the expression will be evaluated again.
		91
		92	For example, an expression such as C<scale keep { load "$HOME/mybg.png"
		93	}> scales the image to the window size, so it relies on the window size
		94	and will be reevaluated each time it is changed, but not when it moves for
		95	example. That ensures that the picture always fills the terminal, even
		96	after its size changes.
		97
		98	=head2 EXPRESSIONS
		99
		100	Expressions are normal Perl expressions, in fact, they are Perl blocks -
		101	which means you could use multiple lines and statements:
		102
		103	scale keep {
		104	again 3600;
		105	if (localtime now)[6]) {
		106	return load "$HOME/weekday.png";
		107	} else {
		108	return load "$HOME/sunday.png";
		109	}
		110	}
		111
		112	This inner expression is evaluated once per hour (and whenever the
		113	terminal window is resized). It sets F<sunday.png> as background on
		114	Sundays, and F<weekday.png> on all other days.
		115
		116	Fortunately, we expect that most expressions will be much simpler, with
		117	little Perl knowledge needed.
		118
		119	Basically, you always start with a function that "generates" an image
		120	object, such as C<load>, which loads an image from disk, or C<root>, which
		121	returns the root window background image:
		122
		123	load "$HOME/mypic.png"
		124
		125	The path is usually specified as a quoted string (the exact rules can be
		126	found in the L<perlop> manpage). The F<$HOME> at the beginning of the
		127	string is expanded to the home directory.
		128
		129	Then you prepend one or more modifiers or filtering expressions, such as
		130	C<scale>:
		131
		132	scale load "$HOME/mypic.png"
		133
		134	Just like a mathematical expression with functions, you should read these
		135	expressions from right to left, as the C<load> is evaluated first, and
		136	its result becomes the argument to the C<scale> function.
		137
		138	Many operators also allow some parameters preceding the input image
		139	that modify its behaviour. For example, C<scale> without any additional
		140	arguments scales the image to size of the terminal window. If you specify
		141	an additional argument, it uses it as a scale factor (multiply by 100 to
		142	get a percentage):
		143
		144	scale 2, load "$HOME/mypic.png"
		145
		146	This enlarges the image by a factor of 2 (200%). As you can see, C<scale>
		147	has now two arguments, the C<2> and the C<load> expression, while
		148	C<load> only has one argument. Arguments are separated from each other by
		149	commas.
		150
		151	Scale also accepts two arguments, which are then separate factors for both
		152	horizontal and vertical dimensions. For example, this halves the image
		153	width and doubles the image height:
		154
		155	scale 0.5, 2, load "$HOME/mypic.png"
		156
		157	IF you try out these expressions, you might suffer from some sluggishness,
		158	because each time the terminal is resized, it loads the PNG image again
		159	and scales it. Scaling is usually fast (and unavoidable), but loading the
		160	image can be quite time consuming. This is where C<keep> comes in handy:
		161
		162	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		163
		164	The C<keep> operator executes all the statements inside the braces only
		165	once, or when it thinks the outcome might change. In other cases it
		166	returns the last value computed by the brace block.
		167
		168	This means that the C<load> is only executed once, which makes it much
		169	faster, but also means that more memory is being used, because the loaded
		170	image must be kept in memory at all times. In this expression, the
		171	trade-off is likely worth it.
		172
		173	But back to effects: Other effects than scaling are also readily
		174	available, for example, you can tile the image to fill the whole window,
		175	instead of resizing it:
		176
		177	tile keep { load "$HOME/mypic.png" }
		178
		179	In fact, images returned by C<load> are in C<tile> mode by default, so the
		180	C<tile> operator is kind of superfluous.
		181
		182	Another common effect is to mirror the image, so that the same edges
		183	touch:
		184
		185	mirror keep { load "$HOME/mypic.png" }
		186
		187	Another common background expression is:
		188
		189	rootalign root
		190
		191	This one first takes a snapshot of the screen background image, and then
		192	moves it to the upper left corner of the screen (as opposed to the upper
		193	left corner of the terminal window)- the result is pseudo-transparency:
		194	the image seems to be static while the window is moved around.
		195
		196	=head2 COLOUR SPECIFICATIONS
		197
		198	Whenever an operator expects a "colour", then this can be specified in one
		199	of two ways: Either as string with an X11 colour specification, such as:
		200
		201	"red" # named colour
		202	"#f00" # simple rgb
		203	"[50]red" # red with 50% alpha
		204	"TekHVC:300/50/50" # anything goes
		205
		206	OR as an array reference with one, three or four components:
		207
		208	[0.5] # 50% gray, 100% alpha
		209	[0.5, 0, 0] # dark red, no green or blur, 100% alpha
		210	[0.5, 0, 0, 0.7] # same with explicit 70% alpha
		211
		212	=head2 CACHING AND SENSITIVITY
		213
		214	Since some operations (such as C<load> and C<blur>) can take a long time,
		215	caching results can be very important for a smooth operation. Caching can
		216	also be useful to reduce memory usage, though, for example, when an image
		217	is cached by C<load>, it could be shared by multiple terminal windows
		218	running inside urxvtd.
		219
		220	=head3 C<keep { ... }> caching
		221
		222	The most important way to cache expensive operations is to use C<keep {
		223	... }>. The C<keep> operator takes a block of multiple statements enclosed
		224	by C<{}> and keeps the return value in memory.
		225
		226	An expression can be "sensitive" to various external events, such as
		227	scaling or moving the window, root background changes and timers. Simply
		228	using an expression (such as C<scale> without parameters) that depends on
		229	certain changing values (called "variables"), or using those variables
		230	directly, will make an expression sensitive to these events - for example,
		231	using C<scale> or C<TW> will make the expression sensitive to the terminal
		232	size, and thus to resizing events.
		233
		234	When such an event happens, C<keep> will automatically trigger a
		235	reevaluation of the whole expression with the new value of the expression.
		236
		237	C<keep> is most useful for expensive operations, such as C<blur>:
		238
		239	rootalign keep { blur 20, root }
		240
		241	This makes a blurred copy of the root background once, and on subsequent
		242	calls, just root-aligns it. Since C<blur> is usually quite slow and
		243	C<rootalign> is quite fast, this trades extra memory (for the cached
		244	blurred pixmap) with speed (blur only needs to be redone when root
		245	changes).
		246
		247	=head3 C<load> caching
		248
		249	The C<load> operator itself does not keep images in memory, but as long as
		250	the image is still in memory, C<load> will use the in-memory image instead
		251	of loading it freshly from disk.
		252
		253	That means that this expression:
		254
		255	keep { load "$HOME/path..." }
		256
		257	Not only caches the image in memory, other terminal instances that try to
		258	C<load> it can reuse that in-memory copy.
		259
		260	=head1 REFERENCE
		261
		262	=head2 COMMAND LINE SWITCHES
		263
		264	=over 4
		265
		266	=item --background-expr perl-expression
		267
		268	Specifies the Perl expression to evaluate.
		269
		270	=item --background-border
		271
		272	By default, the expression creates an image that fills the full window,
		273	overwriting borders and any other areas, such as the scrollbar.
		274
		275	Specifying this flag changes the behaviour, so that the image only
		276	replaces the background of the character area.
		277
		278	=item --background-interval seconds
		279
		280	Since some operations in the underlying XRender extension can effectively
		281	freeze your X-server for prolonged time, this extension enforces a minimum
		282	time between updates, which is normally about 0.1 seconds.
		283
		284	If you want to do updates more often, you can decrease this safety
		285	interval with this switch.
		286
		287	=back
		288
		289	=cut
		290
		291	our %_IMG_CACHE;
		292	our $HOME;
		293	our ($self, $frame);
23	our ($x, $y, $w, $h);	294	our ($x, $y, $w, $h, $focus);
24		295
25	# enforce at least this interval between updates	296	# enforce at least this interval between updates
26	our $MIN_INTERVAL = 1/100;	297	our $MIN_INTERVAL = 6/59.951;
27		298
28	{	299	{
29	package urxvt::bgdsl; # background language	300	package urxvt::bgdsl; # background language
		301
		302	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
		303	sub FR_CACHE () { 1 } # cached values
		304	sub FR_AGAIN () { 2 } # what this expr is sensitive to
		305	sub FR_STATE () { 3 } # watchers etc.
		306
		307	use List::Util qw(min max sum shuffle);
30		308
31	=head2 PROVIDERS/GENERATORS	309	=head2 PROVIDERS/GENERATORS
32		310
33	These functions provide an image, by loading it from disk, grabbing it	311	These functions provide an image, by loading it from disk, grabbing it
34	from the root screen or by simply generating it. They are used as starting	312	from the root screen or by simply generating it. They are used as starting
…		…
39	=item load $path	317	=item load $path
40		318
41	Loads the image at the given C<$path>. The image is set to plane tiling	319	Loads the image at the given C<$path>. The image is set to plane tiling
42	mode.	320	mode.
43		321
44	Loaded images will be cached for one cycle.	322	If the image is already in memory (e.g. because another terminal instance
		323	uses it), then the in-memory copy is returned instead.
45		324
		325	=item load_uc $path
		326
		327	Load uncached - same as load, but does not cache the image, which means it
		328	is I<always> loaded from the filesystem again, even if another copy of it
		329	is in memory at the time.
		330
46	=cut	331	=cut
		332
		333	sub load_uc($) {
		334	$self->new_img_from_file ($_[0])
		335	}
47		336
48	sub load($) {	337	sub load($) {
49	my ($path) = @_;	338	my ($path) = @_;
50		339
51	$new->{load}{$path} = $old->{load}{$path} || $bgdsl_self->new_img_from_file ($path);	340	$_IMG_CACHE{$path} || do {
		341	my $img = load_uc $path;
		342	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		343	$img
		344	}
52	}	345	}
53		346
54	=item root	347	=item root
55		348
56	Returns the root window pixmap, that is, hopefully, the background image	349	Returns the root window pixmap, that is, hopefully, the background image
57	of your screen. The image is set to extend mode.	350	of your screen.
58		351
59	This function makes your expression root sensitive, that means it will be	352	This function makes your expression root sensitive, that means it will be
60	reevaluated when the bg image changes.	353	reevaluated when the bg image changes.
61		354
62	=cut	355	=cut
63		356
64	sub root() {	357	sub root() {
65	$new->{rootpmap_sensitive} = 1;	358	$frame->[FR_AGAIN]{rootpmap} = 1;
66	die "root op not supported, exg, we need you";	359	$self->new_img_from_root
67	}	360	}
68		361
69	=item solid $colour	362	=item solid $colour
70		363
71	=item solid $width, $height, $colour	364	=item solid $width, $height, $colour
72		365
73	Creates a new image and completely fills it with the given colour. The	366	Creates a new image and completely fills it with the given colour. The
74	image is set to tiling mode.	367	image is set to tiling mode.
75		368
76	If <$width> and C<$height> are omitted, it creates a 1x1 image, which is	369	If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
77	useful for solid backgrounds or for use in filtering effects.	370	useful for solid backgrounds or for use in filtering effects.
78		371
79	=cut	372	=cut
80		373
81	sub solid($$;$) {	374	sub solid($;$$) {
82	my $colour = pop;	375	my $colour = pop;
83		376
84	my $img = $bgdsl_self->new_img (urxvt::PictStandardARGB32, $_[0] || 1, $_[1] || 1);	377	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] || 1, $_[1] || 1);
85	$img->fill ($colour);	378	$img->fill ($colour);
86	$img	379	$img
87	}	380	}
88		381
89	=back	382	=item clone $img
90		383
91	=head2 VARIABLES	384	Returns an exact copy of the image. This is useful if you want to have
		385	multiple copies of the same image to apply different effects to.
92		386
93	The following functions provide variable data such as the terminal
94	window dimensions. Most of them make your expression sensitive to some
95	events, for example using C<TW> (terminal width) means your expression is
96	evaluated again when the terminal is resized.
97
98	=over 4
99
100	=item TX
101
102	=item TY
103
104	Return the X and Y coordinates of the terminal window (the terminal
105	window is the full window by default, and the character area only when in
106	border-respect mode).
107
108	Using these functions make your expression sensitive to window moves.
109
110	These functions are mainly useful to align images to the root window.
111
112	Example: load an image and align it so it looks as if anchored to the
113	background.
114
115	move -TX, -TY, load "mybg.png"
116
117	=item TW
118
119	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
120	terminal window is the full window by default, and the character area only
121	when in border-respect mode).
122
123	Using these functions make your expression sensitive to window resizes.
124
125	These functions are mainly useful to scale images, or to clip images to
126	the window size to conserve memory.
127
128	Example: take the screen background, clip it to the window size, blur it a
129	bit, align it to the window position and use it as background.
130
131	clip move -TX, -TY, blur 5, root
132
133	=cut	387	=cut
134		388
135	sub TX() { $new->{position_sensitive} = 1; $x }
136	sub TY() { $new->{position_sensitive} = 1; $y }
137	sub TW() { $new->{size_sensitive} = 1; $w }
138	sub TH() { $new->{size_sensitive} = 1; $h }
139
140	sub now() { urxvt::NOW }
141
142	sub again($) {
143	$new->{again} = $_[0];
144	}
145
146	sub counter($) {	389	sub clone($) {
147	$new->{again} = $_[0];	390	$_[0]->clone
148	$bgdsl_self->{counter} + 0	391	}
		392
		393	=item merge $img ...
		394
		395	Takes any number of images and merges them together, creating a single
		396	image containing them all. The tiling mode of the first image is used as
		397	the tiling mode of the resulting image.
		398
		399	This function is called automatically when an expression returns multiple
		400	images.
		401
		402	=cut
		403
		404	sub merge(@) {
		405	return $_[0] unless $#_;
		406
		407	# rather annoyingly clumsy, but optimisation is for another time
		408
		409	my $x0 = +1e9;
		410	my $y0 = +1e9;
		411	my $x1 = -1e9;
		412	my $y1 = -1e9;
		413
		414	for (@_) {
		415	my ($x, $y, $w, $h) = $_->geometry;
		416
		417	$x0 = $x if $x0 > $x;
		418	$y0 = $y if $y0 > $y;
		419
		420	$x += $w;
		421	$y += $h;
		422
		423	$x1 = $x if $x1 < $x;
		424	$y1 = $y if $y1 < $y;
		425	}
		426
		427	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		428	$base->repeat_mode ($_[0]->repeat_mode);
		429	$base->fill ([0, 0, 0, 0]);
		430
		431	$base->draw ($_)
		432	for @_;
		433
		434	$base
149	}	435	}
150		436
151	=back	437	=back
152		438
153	=head2 TILING MODES	439	=head2 TILING MODES
…		…
159		445
160	=item tile $img	446	=item tile $img
161		447
162	Tiles the whole plane with the image and returns this new image - or in	448	Tiles the whole plane with the image and returns this new image - or in
163	other words, it returns a copy of the image in plane tiling mode.	449	other words, it returns a copy of the image in plane tiling mode.
		450
		451	Example: load an image and tile it over the background, without
		452	resizing. The C<tile> call is superfluous because C<load> already defaults
		453	to tiling mode.
		454
		455	tile load "mybg.png"
164		456
165	=item mirror $img	457	=item mirror $img
166		458
167	Similar to tile, but reflects the image each time it uses a new copy, so	459	Similar to tile, but reflects the image each time it uses a new copy, so
168	that top edges always touch top edges, right edges always touch right	460	that top edges always touch top edges, right edges always touch right
169	edges and so on (with normal tiling, left edges always touch right edges	461	edges and so on (with normal tiling, left edges always touch right edges
170	and top always touch bottom edges).	462	and top always touch bottom edges).
171		463
		464	Example: load an image and mirror it over the background, avoiding sharp
		465	edges at the image borders at the expense of mirroring the image itself
		466
		467	mirror load "mybg.png"
		468
172	=item pad $img	469	=item pad $img
173		470
174	Takes an image and modifies it so that all pixels outside the image area	471	Takes an image and modifies it so that all pixels outside the image area
175	become transparent. This mode is most useful when you want to place an	472	become transparent. This mode is most useful when you want to place an
176	image over another image or the background colour while leaving all	473	image over another image or the background colour while leaving all
177	background pixels outside the image unchanged.	474	background pixels outside the image unchanged.
178		475
		476	Example: load an image and display it in the upper left corner. The rest
		477	of the space is left "empty" (transparent or whatever your compositor does
		478	in alpha mode, else background colour).
		479
		480	pad load "mybg.png"
		481
179	=item extend $img	482	=item extend $img
180		483
181	Extends the image over the whole plane, using the closest pixel in the	484	Extends the image over the whole plane, using the closest pixel in the
182	area outside the image. This mode is mostly useful when you more complex	485	area outside the image. This mode is mostly useful when you use more complex
183	filtering operations and want the pixels outside the image to have the	486	filtering operations and want the pixels outside the image to have the
184	same values as the pixels near the edge.	487	same values as the pixels near the edge.
		488
		489	Example: just for curiosity, how does this pixel extension stuff work?
		490
		491	extend move 50, 50, load "mybg.png"
185		492
186	=cut	493	=cut
187		494
188	sub pad($) {	495	sub pad($) {
189	my $img = $_[0]->clone;	496	my $img = $_[0]->clone;
…		…
209	$img	516	$img
210	}	517	}
211		518
212	=back	519	=back
213		520
214	=head2 PIXEL OPERATORS	521	=head2 VARIABLE VALUES
215		522
216	The following operators modify the image pixels in various ways.	523	The following functions provide variable data such as the terminal window
		524	dimensions. They are not (Perl-) variables, they just return stuff that
		525	varies. Most of them make your expression sensitive to some events, for
		526	example using C<TW> (terminal width) means your expression is evaluated
		527	again when the terminal is resized.
217		528
218	=over 4	529	=over 4
219		530
220	=item clone $img	531	=item TX
221		532
222	Returns an exact copy of the image.	533	=item TY
223		534
224	=cut	535	Return the X and Y coordinates of the terminal window (the terminal
		536	window is the full window by default, and the character area only when in
		537	border-respect mode).
225		538
		539	Using these functions makes your expression sensitive to window moves.
		540
		541	These functions are mainly useful to align images to the root window.
		542
		543	Example: load an image and align it so it looks as if anchored to the
		544	background (that's exactly what C<rootalign> does btw.):
		545
		546	move -TX, -TY, keep { load "mybg.png" }
		547
		548	=item TW
		549
		550	=item TH
		551
		552	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		553	terminal window is the full window by default, and the character area only
		554	when in border-respect mode).
		555
		556	Using these functions makes your expression sensitive to window resizes.
		557
		558	These functions are mainly useful to scale images, or to clip images to
		559	the window size to conserve memory.
		560
		561	Example: take the screen background, clip it to the window size, blur it a
		562	bit, align it to the window position and use it as background.
		563
		564	clip move -TX, -TY, keep { blur 5, root }
		565
		566	=item FOCUS
		567
		568	Returns a boolean indicating whether the terminal window has keyboard
		569	focus, in which case it returns true.
		570
		571	Using this function makes your expression sensitive to focus changes.
		572
		573	A common use case is to fade the background image when the terminal loses
		574	focus, often together with the C<-fade> command line option. In fact,
		575	there is a special function for just that use case: C<focus_fade>.
		576
		577	Example: use two entirely different background images, depending on
		578	whether the window has focus.
		579
		580	FOCUS ? keep { load "has_focus.jpg" } : keep { load "no_focus.jpg" }
		581
		582	=cut
		583
		584	sub TX () { $frame->[FR_AGAIN]{position} = 1; $x }
		585	sub TY () { $frame->[FR_AGAIN]{position} = 1; $y }
		586	sub TW () { $frame->[FR_AGAIN]{size} = 1; $w }
		587	sub TH () { $frame->[FR_AGAIN]{size} = 1; $h }
		588	sub FOCUS() { $frame->[FR_AGAIN]{focus} = 1; $focus }
		589
		590	=item now
		591
		592	Returns the current time as (fractional) seconds since the epoch.
		593
		594	Using this expression does I<not> make your expression sensitive to time,
		595	but the next two functions do.
		596
		597	=item again $seconds
		598
		599	When this function is used the expression will be reevaluated again in
		600	C<$seconds> seconds.
		601
		602	Example: load some image and rotate it according to the time of day (as if it were
		603	the hour pointer of a clock). Update this image every minute.
		604
		605	again 60;
		606	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
		607
		608	=item counter $seconds
		609
		610	Like C<again>, but also returns an increasing counter value, starting at
		611	0, which might be useful for some simple animation effects.
		612
		613	=cut
		614
		615	sub now() { urxvt::NOW }
		616
		617	sub again($) {
		618	$frame->[FR_AGAIN]{time} = $_[0];
		619	}
		620
226	sub clone($) {	621	sub counter($) {
227	$_[0]->clone	622	$frame->[FR_AGAIN]{time} = $_[0];
		623	$frame->[FR_STATE]{counter} + 0
228	}	624	}
		625
		626	=back
		627
		628	=head2 SHAPE CHANGING OPERATORS
		629
		630	The following operators modify the shape, size or position of the image.
		631
		632	=over 4
229		633
230	=item clip $img	634	=item clip $img
231		635
232	=item clip $width, $height, $img	636	=item clip $width, $height, $img
233		637
…		…
236	Clips an image to the given rectangle. If the rectangle is outside the	640	Clips an image to the given rectangle. If the rectangle is outside the
237	image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is	641	image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is
238	larger than the image, then the tiling mode defines how the extra pixels	642	larger than the image, then the tiling mode defines how the extra pixels
239	will be filled.	643	will be filled.
240		644
241	If C<$x> an C<$y> are missing, then C<0> is assumed for both.	645	If C<$x> and C<$y> are missing, then C<0> is assumed for both.
242		646
243	If C<$width> and C<$height> are missing, then the window size will be	647	If C<$width> and C<$height> are missing, then the window size will be
244	assumed.	648	assumed.
245		649
246	Example: load an image, blur it, and clip it to the window size to save	650	Example: load an image, blur it, and clip it to the window size to save
247	memory.	651	memory.
248		652
249	clip blur 10, load "mybg.png"	653	clip keep { blur 10, load "mybg.png" }
250		654
251	=cut	655	=cut
252		656
253	sub clip($;$$;$$) {	657	sub clip($;$$;$$) {
254	my $img = pop;	658	my $img = pop;
…		…
257	$img->sub_rect ($_[0], $_[1], $w, $h)	661	$img->sub_rect ($_[0], $_[1], $w, $h)
258	}	662	}
259		663
260	=item scale $img	664	=item scale $img
261		665
262	=item scale $size_percent, $img	666	=item scale $size_factor, $img
263		667
264	=item scale $width_percent, $height_percent, $img	668	=item scale $width_factor, $height_factor, $img
265		669
266	Scales the image by the given percentages in horizontal	670	Scales the image by the given factors in horizontal
267	(C<$width_percent>) and vertical (C<$height_percent>) direction.	671	(C<$width>) and vertical (C<$height>) direction.
268		672
269	If only one percentage is give, it is used for both directions.	673	If only one factor is given, it is used for both directions.
270		674
271	If no percentages are given, scales the image to the window size without	675	If no factors are given, scales the image to the window size without
272	keeping aspect.	676	keeping aspect.
273		677
274	=item resize $width, $height, $img	678	=item resize $width, $height, $img
275		679
276	Resizes the image to exactly C<$width> times C<$height> pixels.	680	Resizes the image to exactly C<$width> times C<$height> pixels.
277		681
278	=cut	682	=item fit $img
279		683
280	#TODO: maximise, maximise_fill?	684	=item fit $width, $height, $img
281		685
		686	Fits the image into the given C<$width> and C<$height> without changing
		687	aspect, or the terminal size. That means it will be shrunk or grown until
		688	the whole image fits into the given area, possibly leaving borders.
		689
		690	=item cover $img
		691
		692	=item cover $width, $height, $img
		693
		694	Similar to C<fit>, but shrinks or grows until all of the area is covered
		695	by the image, so instead of potentially leaving borders, it will cut off
		696	image data that doesn't fit.
		697
		698	=cut
		699
282	sub scale($$$) {	700	sub scale($;$;$) {
283	my $img = pop;	701	my $img = pop;
284		702
285	@_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01)	703	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
286	: @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01)	704	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
287	: $img->scale (TW, TH)	705	: $img->scale (TW, TH)
288	}	706	}
289		707
290	sub resize($$$) {	708	sub resize($$$) {
291	my $img = pop;	709	my $img = pop;
292	$img->scale ($_[0], $_[1])	710	$img->scale ($_[0], $_[1])
293	}	711	}
		712
		713	sub fit($;$$) {
		714	my $img = pop;
		715	my $w = ($_[0] || TW) / $img->w;
		716	my $h = ($_[1] || TH) / $img->h;
		717	scale +(min $w, $h), $img
		718	}
		719
		720	sub cover($;$$) {
		721	my $img = pop;
		722	my $w = ($_[0] || TW) / $img->w;
		723	my $h = ($_[1] || TH) / $img->h;
		724	scale +(max $w, $h), $img
		725	}
		726
		727	=item move $dx, $dy, $img
		728
		729	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
		730	the vertical.
		731
		732	Example: move the image right by 20 pixels and down by 30.
		733
		734	move 20, 30, ...
		735
		736	=item align $xalign, $yalign, $img
		737
		738	Aligns the image according to a factor - C<0> means the image is moved to
		739	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		740	exactly centered and C<1> means it touches the right or bottom edge.
		741
		742	Example: remove any visible border around an image, center it vertically but move
		743	it to the right hand side.
		744
		745	align 1, 0.5, pad $img
		746
		747	=item center $img
		748
		749	=item center $width, $height, $img
		750
		751	Centers the image, i.e. the center of the image is moved to the center of
		752	the terminal window (or the box specified by C<$width> and C<$height> if
		753	given).
		754
		755	Example: load an image and center it.
		756
		757	center keep { pad load "mybg.png" }
		758
		759	=item rootalign $img
		760
		761	Moves the image so that it appears glued to the screen as opposed to the
		762	window. This gives the illusion of a larger area behind the window. It is
		763	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
		764	top left of the screen.
		765
		766	Example: load a background image, put it in mirror mode and root align it.
		767
		768	rootalign keep { mirror load "mybg.png" }
		769
		770	Example: take the screen background and align it, giving the illusion of
		771	transparency as long as the window isn't in front of other windows.
		772
		773	rootalign root
		774
		775	=cut
294		776
295	sub move($$;$) {	777	sub move($$;$) {
296	my $img = pop->clone;	778	my $img = pop->clone;
297	$img->move ($_[0], $_[1]);	779	$img->move ($_[0], $_[1]);
298	$img	780	$img
299	}	781	}
300		782
		783	sub align($;$$) {
		784	my $img = pop;
		785
		786	move $_[0] * (TW - $img->w),
		787	$_[1] * (TH - $img->h),
		788	$img
		789	}
		790
		791	sub center($;$$) {
		792	my $img = pop;
		793	my $w = $_[0] || TW;
		794	my $h = $_[1] || TH;
		795
		796	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		797	}
		798
		799	sub rootalign($) {
		800	move -TX, -TY, $_[0]
		801	}
		802
		803	=item rotate $center_x, $center_y, $degrees, $img
		804
		805	Rotates the image clockwise by C<$degrees> degrees, around the point at
		806	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		807
		808	Example: rotate the image by 90 degrees around its center.
		809
		810	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		811
		812	=cut
		813
301	sub rotate($$$$$$) {	814	sub rotate($$$$) {
302	my $img = pop;	815	my $img = pop;
303	$img->rotate (	816	$img->rotate (
304	$_[0],	817	$_[0] * ($img->w + $img->x),
305	$_[1],	818	$_[1] * ($img->h + $img->y),
306	$_[2] * $img->w * .01,
307	$_[3] * $img->h * .01,
308	$_[4] * (3.14159265 / 180),	819	$_[2] * (3.14159265 / 180),
309	)	820	)
310	}	821	}
		822
		823	=back
		824
		825	=head2 COLOUR MODIFICATIONS
		826
		827	The following operators change the pixels of the image.
		828
		829	=over 4
		830
		831	=item tint $color, $img
		832
		833	Tints the image in the given colour.
		834
		835	Example: tint the image red.
		836
		837	tint "red", load "rgb.png"
		838
		839	Example: the same, but specify the colour by component.
		840
		841	tint [1, 0, 0], load "rgb.png"
		842
		843	=cut
		844
		845	sub tint($$) {
		846	$_[1]->tint ($_[0])
		847	}
		848
		849	=item shade $factor, $img
		850
		851	Shade the image by the given factor.
		852
		853	=cut
		854
		855	sub shade($$) {
		856	$_[1]->shade ($_[0])
		857	}
		858
		859	=item contrast $factor, $img
		860
		861	=item contrast $r, $g, $b, $img
		862
		863	=item contrast $r, $g, $b, $a, $img
		864
		865	Adjusts the I<contrast> of an image.
		866
		867	The first form applies a single C<$factor> to red, green and blue, the
		868	second form applies separate factors to each colour channel, and the last
		869	form includes the alpha channel.
		870
		871	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		872	contrast.
		873
		874	Due to limitations in the underlying XRender extension, lowering contrast
		875	also reduces brightness, while increasing contrast currently also
		876	increases brightness.
		877
		878	=item brightness $bias, $img
		879
		880	=item brightness $r, $g, $b, $img
		881
		882	=item brightness $r, $g, $b, $a, $img
		883
		884	Adjusts the brightness of an image.
		885
		886	The first form applies a single C<$bias> to red, green and blue, the
		887	second form applies separate biases to each colour channel, and the last
		888	form includes the alpha channel.
		889
		890	Values less than 0 reduce brightness, while values larger than 0 increase
		891	it. Useful range is from -1 to 1 - the former results in a black, the
		892	latter in a white picture.
		893
		894	Due to idiosyncrasies in the underlying XRender extension, biases less
		895	than zero can be I<very> slow.
		896
		897	You can also try the experimental(!) C<muladd> operator.
		898
		899	=cut
		900
		901	sub contrast($$;$$;$) {
		902	my $img = pop;
		903	my ($r, $g, $b, $a) = @_;
		904
		905	($g, $b) = ($r, $r) if @_ < 3;
		906	$a = 1 if @_ < 4;
		907
		908	$img = $img->clone;
		909	$img->contrast ($r, $g, $b, $a);
		910	$img
		911	}
		912
		913	sub brightness($$;$$;$) {
		914	my $img = pop;
		915	my ($r, $g, $b, $a) = @_;
		916
		917	($g, $b) = ($r, $r) if @_ < 3;
		918	$a = 1 if @_ < 4;
		919
		920	$img = $img->clone;
		921	$img->brightness ($r, $g, $b, $a);
		922	$img
		923	}
		924
		925	=item muladd $mul, $add, $img # EXPERIMENTAL
		926
		927	First multiplies the pixels by C<$mul>, then adds C<$add>. This can be used
		928	to implement brightness and contrast at the same time, with a wider value
		929	range than contrast and brightness operators.
		930
		931	Due to numerous bugs in XRender implementations, it can also introduce a
		932	number of visual artifacts.
		933
		934	Example: increase contrast by a factor of C<$c> without changing image
		935	brightness too much.
		936
		937	muladd $c, (1 - $c) * 0.5, $img
		938
		939	=cut
		940
		941	sub muladd($$$) {
		942	$_[2]->muladd ($_[0], $_[1])
		943	}
		944
		945	=item blur $radius, $img
		946
		947	=item blur $radius_horz, $radius_vert, $img
		948
		949	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
		950	can also be specified separately.
		951
		952	Blurring is often I<very> slow, at least compared or other
		953	operators. Larger blur radii are slower than smaller ones, too, so if you
		954	don't want to freeze your screen for long times, start experimenting with
		955	low values for radius (<5).
		956
		957	=cut
311		958
312	sub blur($$;$) {	959	sub blur($$;$) {
313	my $img = pop;	960	my $img = pop;
314	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	961	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
315	}	962	}
316		963
317	sub contrast($$;$$;$) {	964	=item focus_fade $img
		965
		966	=item focus_fade $factor, $img
		967
		968	=item focus_fade $factor, $color, $img
		969
		970	Fades the image by the given factor (and colour) when focus is lost (the
		971	same as the C<-fade>/C<-fadecolor> command line options, which also supply
		972	the default values for C<factor> and C<$color>. Unlike with C<-fade>, the
		973	C<$factor> is a real value, not a percentage value (that is, 0..1, not
		974	0..100).
		975
		976	Example: do the right thing when focus fading is requested.
		977
		978	focus_fade load "mybg.jpg";
		979
		980	=cut
		981
		982	sub focus_fade($;$$) {
318	my $img = pop;	983	my $img = pop;
319	my ($r, $g, $b, $a) = @_;
320		984
321	($g, $b) = ($r, $r) if @_ < 4;	985	return $img
322	$a = 1 if @_ < 5;	986	if FOCUS;
323		987
324	$img = $img->clone;	988	my $fade = @_ >= 1 ? $_[0] : defined $self->resource ("fade") ? $self->resource ("fade") * 0.01 : 0;
325	$img->contrast ($r, $g, $b, $a);	989	my $color = @_ >= 2 ? $_[1] : $self->resource ("color+" . urxvt::Color_fade);
		990
		991	$img = $img->tint ($color) if $color ne "rgb:00/00/00";
		992	$img = $img->muladd (1 - $fade, 0) if $fade;
		993
326	$img	994	$img
327	}	995	}
328		996
329	sub brightness($$;$$;$) {
330	my $img = pop;
331	my ($r, $g, $b, $a) = @_;
332
333	($g, $b) = ($r, $r) if @_ < 4;
334	$a = 1 if @_ < 5;
335
336	$img = $img->clone;
337	$img->brightness ($r, $g, $b, $a);
338	$img
339	}
340
341	=back	997	=back
342		998
		999	=head2 OTHER STUFF
		1000
		1001	Anything that didn't fit any of the other categories, even after applying
		1002	force and closing our eyes.
		1003
		1004	=over 4
		1005
		1006	=item keep { ... }
		1007
		1008	This operator takes a code block as argument, that is, one or more
		1009	statements enclosed by braces.
		1010
		1011	The trick is that this code block is only evaluated when the outcome
		1012	changes - on other calls the C<keep> simply returns the image it computed
		1013	previously (yes, it should only be used with images). Or in other words,
		1014	C<keep> I<caches> the result of the code block so it doesn't need to be
		1015	computed again.
		1016
		1017	This can be extremely useful to avoid redoing slow operations - for
		1018	example, if your background expression takes the root background, blurs it
		1019	and then root-aligns it it would have to blur the root background on every
		1020	window move or resize.
		1021
		1022	Another example is C<load>, which can be quite slow.
		1023
		1024	In fact, urxvt itself encloses the whole expression in some kind of
		1025	C<keep> block so it only is reevaluated as required.
		1026
		1027	Putting the blur into a C<keep> block will make sure the blur is only done
		1028	once, while the C<rootalign> is still done each time the window moves.
		1029
		1030	rootalign keep { blur 10, root }
		1031
		1032	This leaves the question of how to force reevaluation of the block,
		1033	in case the root background changes: If expression inside the block
		1034	is sensitive to some event (root background changes, window geometry
		1035	changes), then it will be reevaluated automatically as needed.
		1036
		1037	=back
		1038
		1039	=head1 OLD BACKGROUND IMAGE SETTINGS
		1040
		1041	This extension also provides support for the old options/resources and
		1042	OSC sequences for setting a background image. These settings are
		1043	B<deprecated> and will be removed in future versions.
		1044
		1045	=head2 OPTIONS AND RESOURCES
		1046
		1047	=over 4
		1048
		1049	=item B<-pixmap> I<file[;oplist]>
		1050
		1051	=item B<backgroundPixmap:> I<file[;oplist]>
		1052
		1053	Use the specified image file as the window's background and also
		1054	optionally specify a colon separated list of operations to modify it.
		1055	Note that you may need to quote the C<;> character when using the
		1056	command line option, as C<;> is usually a metacharacter in shells.
		1057	Supported operations are:
		1058
		1059	=over 4
		1060
		1061	=item B<WxH+X+Y>
		1062
		1063	sets scale and position. B<"W" / "H"> specify the horizontal/vertical
		1064	scale (percent), and B<"X" / "Y"> locate the image centre (percent). A
		1065	scale of 0 disables scaling.
		1066
		1067	=item B<op=tile>
		1068
		1069	enables tiling
		1070
		1071	=item B<op=keep-aspect>
		1072
		1073	maintain the image aspect ratio when scaling
		1074
		1075	=item B<op=root-align>
		1076
		1077	use the position of the terminal window relative to the root window as
		1078	the image offset, simulating a root window background
		1079
		1080	=back
		1081
		1082	The default scale and position setting is C<100x100+50+50>.
		1083	Alternatively, a predefined set of templates can be used to achieve
		1084	the most common setups:
		1085
		1086	=over 4
		1087
		1088	=item B<style=tiled>
		1089
		1090	the image is tiled with no scaling. Equivalent to 0x0+0+0:op=tile
		1091
		1092	=item B<style=aspect-stretched>
		1093
		1094	the image is scaled to fill the whole window maintaining the aspect
		1095	ratio and centered. Equivalent to 100x100+50+50:op=keep-aspect
		1096
		1097	=item B<style=stretched>
		1098
		1099	the image is scaled to fill the whole window. Equivalent to 100x100
		1100
		1101	=item B<style=centered>
		1102
		1103	the image is centered with no scaling. Equivalent to 0x0+50+50
		1104
		1105	=item B<style=root-tiled>
		1106
		1107	the image is tiled with no scaling and using 'root' positioning.
		1108	Equivalent to 0x0:op=tile:op=root-align
		1109
		1110	=back
		1111
		1112	If multiple templates are specified the last one wins. Note that a
		1113	template overrides all the scale, position and operations settings.
		1114
		1115	If used in conjunction with pseudo-transparency, the specified image
		1116	will be blended over the transparent background using alpha-blending.
		1117
		1118	=item B<-tr>|B<+tr>
		1119
		1120	=item B<transparent:> I<boolean>
		1121
		1122	Turn on/off pseudo-transparency by using the root pixmap as background.
		1123
		1124	=item B<-tint> I<colour>
		1125
		1126	=item B<tintColor:> I<colour>
		1127
		1128	Tint the transparent background with the given colour. Note that a
		1129	black tint yields a completely black image while a white tint yields
		1130	the image unchanged.
		1131
		1132	=item B<-sh> I<number>
		1133
		1134	=item B<shading:> I<number>
		1135
		1136	Darken (0 .. 99) or lighten (101 .. 200) the transparent background.
		1137	A value of 100 means no shading.
		1138
		1139	=item B<-blr> I<HxV>
		1140
		1141	=item B<blurRadius:> I<HxV>
		1142
		1143	Apply gaussian blur with the specified radius to the transparent
		1144	background. If a single number is specified, the vertical and
		1145	horizontal radii are considered to be the same. Setting one of the
		1146	radii to 1 and the other to a large number creates interesting effects
		1147	on some backgrounds. The maximum radius value is 128. An horizontal or
		1148	vertical radius of 0 disables blurring.
		1149
		1150	=back
		1151
		1152	=head2 OSC sequences
		1153
		1154	=over 4
		1155
		1156	=item B<< C<ESC ] 705 ; Pt ST> >> Change transparent background tint colour to B<< C<Pt> >>.
		1157
		1158	=item B<< C<ESC ] 20 ; Pt ST> >> Change/Query background image
		1159	parameters: the value of B<< C<Pt> >> can be one of the following
		1160	commands:
		1161
		1162	=over 4
		1163
		1164	=item B<< C<?> >>
		1165
		1166	display scale and position in the title
		1167
		1168	=item B<< C<;WxH+X+Y> >>
		1169
		1170	change scale and/or position
		1171
		1172	=item B<< C<FILE;WxH+X+Y> >>
		1173
		1174	change background image
		1175
		1176	=back
		1177
		1178	=cut
		1179
		1180	sub keep(&) {
		1181	my $id = $_[0]+0;
		1182
		1183	local $frame = $self->{frame_cache}{$id} ||= [$frame];
		1184
		1185	unless ($frame->[FR_CACHE]) {
		1186	$frame->[FR_CACHE] = [ $_[0]() ];
		1187
		1188	my $self = $self;
		1189	my $frame = $frame;
		1190	Scalar::Util::weaken $frame;
		1191	$self->compile_frame ($frame, sub {
		1192	# clear this frame cache, also for all parents
		1193	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		1194	undef $frame->[FR_CACHE];
		1195	}
		1196
		1197	$self->recalculate;
		1198	});
		1199	};
		1200
		1201	# in scalar context we always return the first original result, which
		1202	# is not quite how perl works.
		1203	wantarray
		1204	? @{ $frame->[FR_CACHE] }
		1205	: $frame->[FR_CACHE][0]
		1206	}
		1207
		1208	# sub keep_clear() {
		1209	# delete $self->{frame_cache};
		1210	# }
		1211
		1212	=back
		1213
343	=cut	1214	=cut
344		1215
345	}	1216	}
346		1217
347	sub parse_expr {	1218	sub parse_expr {
348	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	1219	my $expr = eval
		1220	"sub {\n"
		1221	. "package urxvt::bgdsl;\n"
		1222	. "#line 0 'background expression'\n"
		1223	. "$_[0]\n"
		1224	. "}";
349	die if $@;	1225	die if $@;
350	$expr	1226	$expr
351	}	1227	}
352		1228
353	# compiles a parsed expression	1229	# compiles a parsed expression
354	sub set_expr {	1230	sub set_expr {
355	my ($self, $expr) = @_;	1231	my ($self, $expr) = @_;
356		1232
		1233	$self->{root} = []; # the outermost frame
357	$self->{expr} = $expr;	1234	$self->{expr} = $expr;
358	$self->recalculate;	1235	$self->recalculate;
359	}	1236	}
360		1237
		1238	# takes a hash of sensitivity indicators and installs watchers
		1239	sub compile_frame {
		1240	my ($self, $frame, $cb) = @_;
		1241
		1242	my $state = $frame->[urxvt::bgdsl::FR_STATE] ||= {};
		1243	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		1244
		1245	# don't keep stuff alive
		1246	Scalar::Util::weaken $state;
		1247
		1248	if ($again->{nested}) {
		1249	$state->{nested} = 1;
		1250	} else {
		1251	delete $state->{nested};
		1252	}
		1253
		1254	if (my $interval = $again->{time}) {
		1255	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		1256	if $state->{time}[0] != $interval;
		1257
		1258	# callback *might* have changed, although we could just rule that out
		1259	$state->{time}[1]->cb (sub {
		1260	++$state->{counter};
		1261	$cb->();
		1262	});
		1263	} else {
		1264	delete $state->{time};
		1265	}
		1266
		1267	if ($again->{position}) {
		1268	$state->{position} = $self->on (position_change => $cb);
		1269	} else {
		1270	delete $state->{position};
		1271	}
		1272
		1273	if ($again->{size}) {
		1274	$state->{size} = $self->on (size_change => $cb);
		1275	} else {
		1276	delete $state->{size};
		1277	}
		1278
		1279	if ($again->{rootpmap}) {
		1280	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		1281	} else {
		1282	delete $state->{rootpmap};
		1283	}
		1284
		1285	if ($again->{focus}) {
		1286	$state->{focus} = $self->on (focus_in => $cb, focus_out => $cb);
		1287	} else {
		1288	delete $state->{focus};
		1289	}
		1290	}
		1291
361	# evaluate the current bg expression	1292	# evaluate the current bg expression
362	sub recalculate {	1293	sub recalculate {
363	my ($self) = @_;	1294	my ($arg_self) = @_;
364		1295
365	# rate limit evaluation	1296	# rate limit evaluation
366		1297
367	if ($self->{next_refresh} > urxvt::NOW) {	1298	if ($arg_self->{next_refresh} > urxvt::NOW) {
368	$self->{next_refresh_timer} = urxvt::timer->new->after ($self->{next_refresh} - urxvt::NOW)->cb (sub {	1299	$arg_self->{next_refresh_timer} = urxvt::timer->new->after ($arg_self->{next_refresh} - urxvt::NOW)->cb (sub {
369	$self->recalculate;	1300	$arg_self->recalculate;
370	});	1301	});
371	return;	1302	return;
372	}	1303	}
373		1304
374	$self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1305	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
		1306
		1307	unless ($arg_self->has_render) {
		1308	warn "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1309	return;
		1310	}
375		1311
376	# set environment to evaluate user expression	1312	# set environment to evaluate user expression
377		1313
378	local $bgdsl_self = $self;	1314	local $self = $arg_self;
379		1315	local $HOME = $ENV{HOME};
380	local $old = $self->{state};	1316	local $frame = $self->{root};
381	local $new = my $state = $self->{state} = {};
382		1317
383	my $border = 0; #d#	1318	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
384		1319	$focus = $self->focus;
385	($x, $y, $w, $h) =
386	$self->background_geometry ($border);
387		1320
388	# evaluate user expression	1321	# evaluate user expression
389		1322
390	my $img = eval { $self->{expr}->() };	1323	my @img = eval { $self->{expr}->() };
391	warn $@ if $@;#d#	1324	die $@ if $@;
		1325	die "background-expr did not return anything.\n" unless @img;
		1326	die "background-expr: expected image(s), got something else.\n"
392	die if !UNIVERSAL::isa $img, "urxvt::img";	1327	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
		1328
		1329	my $img = urxvt::bgdsl::merge @img;
		1330
		1331	$frame->[FR_AGAIN]{size} = 1
		1332	if $img->repeat_mode != urxvt::RepeatNormal;
393		1333
394	# if the expression is sensitive to external events, prepare reevaluation then	1334	# if the expression is sensitive to external events, prepare reevaluation then
395		1335	$self->compile_frame ($frame, sub { $arg_self->recalculate });
396	my $repeat;
397
398	if (my $again = $state->{again}) {
399	$repeat = 1;
400	$state->{timer} = $again == $old->{again}
401	? $old->{timer}
402	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
403	++$self->{counter};
404	$self->recalculate
405	});
406	}
407
408	if (delete $state->{position_sensitive}) {
409	$repeat = 1;
410	$self->enable (position_change => sub { $_[0]->recalculate });
411	} else {
412	$self->disable ("position_change");
413	}
414
415	if (delete $state->{size_sensitive}) {
416	$repeat = 1;
417	$self->enable (size_change => sub { $_[0]->recalculate });
418	} else {
419	$self->disable ("size_change");
420	}
421
422	if (delete $state->{rootpmap_sensitive}) {
423	$repeat = 1;
424	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
425	} else {
426	$self->disable ("rootpmap_change");
427	}
428		1336
429	# clear stuff we no longer need	1337	# clear stuff we no longer need
430		1338
431	%$old = ();	1339	# unless (%{ $frame->[FR_STATE] }) {
432
433	unless ($repeat) {
434	delete $self->{state};	1340	# delete $self->{state};
435	delete $self->{expr};	1341	# delete $self->{expr};
436	}	1342	# }
437		1343
438	# prepare and set background pixmap	1344	# set background pixmap
439		1345
440	$img = $img->sub_rect (0, 0, $w, $h)
441	if $img->w != $w || $img->h != $h;
442
443	$self->set_background ($img, $border);	1346	$self->set_background ($img, $self->{border});
444	$self->scr_recolour (0);	1347	$self->scr_recolor (0);
445	$self->want_refresh;	1348	$self->want_refresh;
446	}	1349	}
447		1350
		1351	sub old_bg_opts {
		1352	my ($self, $arg) = @_;
		1353
		1354	$arg or return;
		1355
		1356	my @str = split /;/, $arg;
		1357
		1358	return unless $str[0] or $self->{bg_opts}->{path};
		1359
		1360	my $bg_opts = $self->{bg_opts};
		1361
		1362	if ($str[0]) {
		1363	$bg_opts->{tile} = 0;
		1364	$bg_opts->{keep_aspect} = 0;
		1365	$bg_opts->{root_align} = 0;
		1366	$bg_opts->{h_scale} = $bg_opts->{v_scale} = 100;
		1367	$bg_opts->{h_align} = $bg_opts->{v_align} = 50;
		1368	$bg_opts->{path} = $str[0];
		1369	}
		1370
		1371	my @oplist = split /:/, $str[1];
		1372
		1373	for (@oplist) {
		1374	if (/style=tiled/i) {
		1375	$bg_opts->{tile} = 1;
		1376	$bg_opts->{keep_aspect} = 0;
		1377	$bg_opts->{root_align} = 0;
		1378	$bg_opts->{h_scale} = $bg_opts->{v_scale} = 0;
		1379	$bg_opts->{h_align} = $bg_opts->{v_align} = 0;
		1380	} elsif (/style=aspect-stretched/i) {
		1381	$bg_opts->{tile} = 0;
		1382	$bg_opts->{keep_aspect} = 1;
		1383	$bg_opts->{root_align} = 0;
		1384	$bg_opts->{h_scale} = $bg_opts->{v_scale} = 100;
		1385	$bg_opts->{h_align} = $bg_opts->{v_align} = 50;
		1386	} elsif (/style=stretched/i) {
		1387	$bg_opts->{tile} = 0;
		1388	$bg_opts->{keep_aspect} = 0;
		1389	$bg_opts->{root_align} = 0;
		1390	$bg_opts->{h_scale} = $bg_opts->{v_scale} = 100;
		1391	$bg_opts->{h_align} = $bg_opts->{v_align} = 50;
		1392	} elsif (/style=centered/i) {
		1393	$bg_opts->{tile} = 0;
		1394	$bg_opts->{keep_aspect} = 0;
		1395	$bg_opts->{root_align} = 0;
		1396	$bg_opts->{h_scale} = $bg_opts->{v_scale} = 0;
		1397	$bg_opts->{h_align} = $bg_opts->{v_align} = 50;
		1398	} elsif (/style=root-tiled/i) {
		1399	$bg_opts->{tile} = 1;
		1400	$bg_opts->{keep_aspect} = 0;
		1401	$bg_opts->{root_align} = 1;
		1402	$bg_opts->{h_scale} = $bg_opts->{v_scale} = 0;
		1403	$bg_opts->{h_align} = $bg_opts->{v_align} = 0;
		1404	} elsif (/op=tile/i) {
		1405	$bg_opts->{tile} = 1;
		1406	} elsif (/op=keep-aspect/i) {
		1407	$bg_opts->{keep_aspect} = 1;
		1408	} elsif (/op=root-align/i) {
		1409	$bg_opts->{root_align} = 1;
		1410	} elsif (/^ =? ([0-9]+)? (?:[xX] ([0-9]+))? ([+-][0-9]+)? ([+-][0-9]+)? $/x) {
		1411	my ($w, $h, $x, $y) = ($1, $2, $3, $4);
		1412
		1413	if ($str[0]) {
		1414	$w = $h unless defined $w;
		1415	$h = $w unless defined $h;
		1416	$y = $x unless defined $y;
		1417	}
		1418
		1419	$bg_opts->{h_scale} = $w if defined $w;
		1420	$bg_opts->{v_scale} = $h if defined $h;
		1421	$bg_opts->{h_align} = $x if defined $x;
		1422	$bg_opts->{v_align} = $y if defined $y;
		1423	}
		1424	}
		1425	}
		1426
		1427	# helper function, quote string as perl without allowing
		1428	# any code execution or other shenanigans. does not
		1429	# support binary NULs in string.
		1430	sub q0 {
		1431	(my $str = shift) =~ s/\x00//g; # make sure there really aren't any embedded NULs
		1432	"q\x00$str\x00"
		1433	}
		1434
		1435	sub old_bg_expr {
		1436	my ($self) = @_;
		1437
		1438	my $expr;
		1439
		1440	my $bg_opts = $self->{bg_opts};
		1441
		1442	if ($bg_opts->{root} =~ /^\s*(?:true|yes|on|1)\s*$/i) {
		1443	$expr .= "tile (";
		1444
		1445	my $shade = $bg_opts->{shade};
		1446
		1447	if ($shade) {
		1448	$shade = List::Util::min $shade, 200;
		1449	$shade = List::Util::max $shade, -100;
		1450	$shade = 200 - (100 + $shade) if $shade < 0;
		1451
		1452	$shade = $shade * 0.01 - 1;
		1453	$expr .= "shade $shade, ";
		1454	}
		1455
		1456	my $tint = $bg_opts->{tint};
		1457
		1458	if ($tint) {
		1459	$tint = q0 $tint;
		1460	$expr .= "tint $tint,";
		1461	}
		1462
		1463	my $blur = $bg_opts->{blur};
		1464
		1465	if ($blur and $blur =~ /^ =? ([0-9]+)? (?:[xX] ([0-9]+))? $/x) {
		1466	my $hr = defined $1 ? $1 : 1;
		1467	my $vr = defined $2 ? $2 : $hr;
		1468
		1469	if ($hr != 0 and $vr != 0) {
		1470	$expr .= "blur $hr, $vr, ";
		1471	}
		1472	}
		1473
		1474	$expr .= "rootalign root)";
		1475	}
		1476
		1477	if ($bg_opts->{path}) {
		1478	my $file_expr;
		1479	my $h_scale = $bg_opts->{h_scale} * 0.01;
		1480	my $v_scale = $bg_opts->{v_scale} * 0.01;
		1481	my $h_align = $bg_opts->{h_align} * 0.01;
		1482	my $v_align = $bg_opts->{v_align} * 0.01;
		1483
		1484	if (!$bg_opts->{tile}) {
		1485	$file_expr .= "pad (";
		1486	} else {
		1487	$file_expr .= "tile (";
		1488	}
		1489
		1490	if ($bg_opts->{root_align}) {
		1491	$file_expr .= "rootalign ";
		1492	} else {
		1493	$file_expr .= "align $h_align, $v_align, ";
		1494	}
		1495
		1496	if ($h_scale != 0 and $v_scale != 0) {
		1497	my $op = $bg_opts->{keep_aspect} ? "fit" : "resize";
		1498	$file_expr .= "$op TW * $h_scale, TH * $v_scale, ";
		1499	}
		1500
		1501	my $path = q0 $bg_opts->{path};
		1502
		1503	$file_expr .= "keep { load $path })";
		1504
		1505	if ($expr) {
		1506	$expr .= ", tint (\"[50]white\", $file_expr)";
		1507	} else {
		1508	$expr = $file_expr;
		1509	}
		1510	}
		1511
		1512	$expr
		1513	}
		1514
		1515	sub on_osc_seq {
		1516	my ($self, $op, $arg) = @_;
		1517
		1518	$self->{bg_opts} or return;
		1519
		1520	$op =~ /^(?:20|705)$/ or return;
		1521
		1522	if ($op eq "20") {
		1523	if ($arg eq "?") {
		1524	my $h_scale = $self->{bg_opts}->{h_scale};
		1525	my $v_scale = $self->{bg_opts}->{v_scale};
		1526	my $h_align = $self->{bg_opts}->{h_align};
		1527	my $v_align = $self->{bg_opts}->{v_align};
		1528	$self->cmd_parse ("\033]2;[${h_scale}x${v_scale}+${h_align}+${v_align}]\007");
		1529	} else {
		1530	$self->old_bg_opts ($arg);
		1531	my $expr = $self->old_bg_expr;
		1532	$self->set_expr (parse_expr $expr) if $expr;
		1533	}
		1534	} elsif ($op eq "705") {
		1535	$self->{bg_opts}->{tint} = $arg;
		1536	my $expr = $self->old_bg_expr;
		1537	$self->set_expr (parse_expr $expr) if $expr;
		1538	}
		1539
		1540	1
		1541	}
		1542
		1543	sub find_resource {
		1544	my ($self, $res, $opt) = @_;
		1545
		1546	my $v = $self->x_resource ($opt);
		1547	$v = $self->x_resource ($res) unless defined $v;
		1548
		1549	$v
		1550	}
		1551
448	sub on_start {	1552	sub on_start {
449	my ($self) = @_;	1553	my ($self) = @_;
450		1554
		1555	my $expr = $self->x_resource ("%.expr");
		1556
		1557	if (!$expr) {
		1558	$self->{bg_opts} = { h_scale => 100, v_scale => 100,
		1559	h_align => 50, v_align => 50 };
		1560
		1561	$self->{bg_opts}{shade} = $self->find_resource ("shading", "sh");
		1562	$self->{bg_opts}{tint} = $self->find_resource ("tintColor", "tint");
		1563	$self->{bg_opts}{blur} = $self->find_resource ("blurRadius", "blr");
		1564	$self->{bg_opts}{root} = $self->find_resource ("transparent", "tr");
		1565
		1566	$self->old_bg_opts ($self->find_resource ("backgroundPixmap", "pixmap"));
		1567	$expr = $self->old_bg_expr;
		1568	}
		1569
		1570	$expr or return;
		1571
451	$self->set_expr (parse_expr $EXPR);	1572	$self->set_expr (parse_expr $expr);
		1573	$self->{border} = $self->x_resource_boolean ("%.border");
		1574
		1575	$MIN_INTERVAL = $self->x_resource ("%.interval");
452		1576
453	()	1577	()
454	}	1578	}
455		1579

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