[ViewVC] Diff of: cvs/rxvt-unicode/src/perl/background

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.52 by root, Tue Jun 12 10:45:53 2012 UTC vs.
Revision 1.91 by sf-exg, Thu Jul 7 17:38:34 2016 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		6
7	=head1 NAME	7	=head1 NAME
8		8
9	background - manage terminal background	9	background - manage terminal background
10		10
11	=head1 SYNOPSIS	11	=head1 SYNOPSIS
12		12
13	urxvt --background-expr 'background expression'	13	urxvt --background-expr 'background expression'
14	--background-border	14	--background-border
15	--background-interval seconds	15	--background-interval seconds
16		16
		17	=head1 QUICK AND DIRTY CHEAT SHEET
		18
		19	Just load a random jpeg image and tile the background with it without
		20	scaling or anything else:
		21
		22	load "/path/to/img.jpg"
		23
		24	The same, but use mirroring/reflection instead of tiling:
		25
		26	mirror load "/path/to/img.jpg"
		27
		28	Load an image and scale it to exactly fill the terminal window:
		29
		30	scale keep { load "/path/to/img.jpg" }
		31
		32	Implement pseudo-transparency by using a suitably-aligned root pixmap
		33	as window background:
		34
		35	rootalign root
		36
		37	Likewise, but keep a blurred copy:
		38
		39	rootalign keep { blur 10, root }
		40
17	=head1 DESCRIPTION	41	=head1 DESCRIPTION
18		42
19	This extension manages the terminal background by creating a picture that	43	This extension manages the terminal background by creating a picture that
20	is behind the text, replacing the normal background colour.	44	is behind the text, replacing the normal background colour.
21		45
26	to be as simple as possible.	50	to be as simple as possible.
27		51
28	For example, to load an image and scale it to the window size, you would	52	For example, to load an image and scale it to the window size, you would
29	use:	53	use:
30		54
31	urxvt --background-expr 'scale load "/path/to/mybg.png"'	55	urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
32		56
33	Or specified as a X resource:	57	Or specified as a X resource:
34		58
35	URxvt.background-expr: scale load "/path/to/mybg.png"	59	URxvt.background.expr: scale keep { load "/path/to/mybg.png" }
36		60
37	=head1 THEORY OF OPERATION	61	=head1 THEORY OF OPERATION
38		62
39	At startup, just before the window is mapped for the first time, the	63	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	64	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	77	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	78	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	79	pixmap is replaced by another one the root background changes; or when the
56	timer elapses), then the expression will be evaluated again.	80	timer elapses), then the expression will be evaluated again.
57		81
58	For example, an expression such as C<scale load "$HOME/mybg.png"> scales the	82	For example, an expression such as C<scale keep { load "$HOME/mybg.png"
59	image to the window size, so it relies on the window size and will	83	}> 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	84	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	85	example. That ensures that the picture always fills the terminal, even
62	after its size changes.	86	after its size changes.
63		87
64	=head2 EXPRESSIONS	88	=head2 EXPRESSIONS
65		89
66	Expressions are normal Perl expressions, in fact, they are Perl blocks -	90	Expressions are normal Perl expressions, in fact, they are Perl blocks -
67	which means you could use multiple lines and statements:	91	which means you could use multiple lines and statements:
68		92
		93	scale keep {
69	again 3600;	94	again 3600;
70	if (localtime now)[6]) {	95	if (localtime now)[6]) {
71	return scale load "$HOME/weekday.png";	96	return load "$HOME/weekday.png";
72	} else {	97	} else {
73	return scale load "$HOME/sunday.png";	98	return load "$HOME/sunday.png";
		99	}
74	}	100	}
75		101
76	This expression gets evaluated once per hour. It will set F<sunday.png> as	102	This inner expression is evaluated once per hour (and whenever the
		103	terminal window is resized). It sets F<sunday.png> as background on
77	background on Sundays, and F<weekday.png> on all other days.	104	Sundays, and F<weekday.png> on all other days.
78		105
79	Fortunately, we expect that most expressions will be much simpler, with	106	Fortunately, we expect that most expressions will be much simpler, with
80	little Perl knowledge needed.	107	little Perl knowledge needed.
81		108
82	Basically, you always start with a function that "generates" an image	109	Basically, you always start with a function that "generates" an image
…		…
105	get a percentage):	132	get a percentage):
106		133
107	scale 2, load "$HOME/mypic.png"	134	scale 2, load "$HOME/mypic.png"
108		135
109	This enlarges the image by a factor of 2 (200%). As you can see, C<scale>	136	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	137	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	138	C<load> only has one argument. Arguments are separated from each other by
112	commas.	139	commas.
113		140
114	Scale also accepts two arguments, which are then separate factors for both	141	Scale also accepts two arguments, which are then separate factors for both
115	horizontal and vertical dimensions. For example, this halves the image	142	horizontal and vertical dimensions. For example, this halves the image
116	width and doubles the image height:	143	width and doubles the image height:
117		144
118	scale 0.5, 2, load "$HOME/mypic.png"	145	scale 0.5, 2, load "$HOME/mypic.png"
119		146
120	Other effects than scaling are also readily available, for example, you can	147	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:	148	because each time the terminal is resized, it loads the PNG image again
		149	and scales it. Scaling is usually fast (and unavoidable), but loading the
		150	image can be quite time consuming. This is where C<keep> comes in handy:
122		151
		152	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		153
		154	The C<keep> operator executes all the statements inside the braces only
		155	once, or when it thinks the outcome might change. In other cases it
		156	returns the last value computed by the brace block.
		157
		158	This means that the C<load> is only executed once, which makes it much
		159	faster, but also means that more memory is being used, because the loaded
		160	image must be kept in memory at all times. In this expression, the
		161	trade-off is likely worth it.
		162
		163	But back to effects: Other effects than scaling are also readily
		164	available, for example, you can tile the image to fill the whole window,
		165	instead of resizing it:
		166
123	tile load "$HOME/mypic.png"	167	tile keep { load "$HOME/mypic.png" }
124		168
125	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator	169	In fact, images returned by C<load> are in C<tile> mode by default, so the
126	is kind of superfluous.	170	C<tile> operator is kind of superfluous.
127		171
128	Another common effect is to mirror the image, so that the same edges touch:	172	Another common effect is to mirror the image, so that the same edges
		173	touch:
129		174
130	mirror load "$HOME/mypic.png"	175	mirror keep { load "$HOME/mypic.png" }
131		176
132	This is also a typical background expression:	177	Another common background expression is:
133		178
134	rootalign root	179	rootalign root
135		180
136	It first takes a snapshot of the screen background image, and then	181	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	182	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	183	left corner of the terminal window)- the result is pseudo-transparency:
139	moved around.	184	the image seems to be static while the window is moved around.
140		185
141	=head2 CYCLES AND CACHING	186	=head2 COLOUR SPECIFICATIONS
142		187
143	As has been mentioned before, the expression might be evaluated multiple	188	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	189	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		190
147	For example, the C<load> operator keeps a copy of the image. If it is	191	"red" # named colour
148	asked to load the same image on the next cycle it will not load it again,	192	"#f00" # simple rgb
149	but return the cached copy.	193	"[50]red" # red with 50% alpha
		194	"TekHVC:300/50/50" # anything goes
150		195
151	This only works for one cycle though, so as long as you load the same	196	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		197
155	This allows you to either speed things up by keeping multiple images in	198	[0.5] # 50% gray, 100% alpha
156	memory, or conserve memory by loading images more often.	199	[0.5, 0, 0] # dark red, no green or blur, 100% alpha
		200	[0.5, 0, 0, 0.7] # same with explicit 70% alpha
157		201
158	For example, you can keep two images in memory and use a random one like	202	=head2 CACHING AND SENSITIVITY
159	this:
160		203
161	my $img1 = load "img1.png";	204	Since some operations (such as C<load> and C<blur>) can take a long time,
162	my $img2 = load "img2.png";	205	caching results can be very important for a smooth operation. Caching can
163	(0.5 > rand) ? $img1 : $img2	206	also be useful to reduce memory usage, though, for example, when an image
		207	is cached by C<load>, it could be shared by multiple terminal windows
		208	running inside urxvtd.
164		209
165	Since both images are "loaded" every time the expression is evaluated,	210	=head3 C<keep { ... }> caching
166	they are always kept in memory. Contrast this version:
167		211
168	my $path1 = "img1.png";	212	The most important way to cache expensive operations is to use C<keep {
169	my $path2 = "img2.png";	213	... }>. The C<keep> operator takes a block of multiple statements enclosed
170	load ((0.5 > rand) ? $path1 : $path2)	214	by C<{}> and keeps the return value in memory.
171		215
172	Here, a path is selected randomly, and load is only called for one image,	216	An expression can be "sensitive" to various external events, such as
173	so keeps only one image in memory. If, on the next evaluation, luck	217	scaling or moving the window, root background changes and timers. Simply
174	decides to use the other path, then it will have to load that image again.	218	using an expression (such as C<scale> without parameters) that depends on
		219	certain changing values (called "variables"), or using those variables
		220	directly, will make an expression sensitive to these events - for example,
		221	using C<scale> or C<TW> will make the expression sensitive to the terminal
		222	size, and thus to resizing events.
		223
		224	When such an event happens, C<keep> will automatically trigger a
		225	reevaluation of the whole expression with the new value of the expression.
		226
		227	C<keep> is most useful for expensive operations, such as C<blur>:
		228
		229	rootalign keep { blur 20, root }
		230
		231	This makes a blurred copy of the root background once, and on subsequent
		232	calls, just root-aligns it. Since C<blur> is usually quite slow and
		233	C<rootalign> is quite fast, this trades extra memory (for the cached
		234	blurred pixmap) with speed (blur only needs to be redone when root
		235	changes).
		236
		237	=head3 C<load> caching
		238
		239	The C<load> operator itself does not keep images in memory, but as long as
		240	the image is still in memory, C<load> will use the in-memory image instead
		241	of loading it freshly from disk.
		242
		243	That means that this expression:
		244
		245	keep { load "$HOME/path..." }
		246
		247	Not only caches the image in memory, other terminal instances that try to
		248	C<load> it can reuse that in-memory copy.
175		249
176	=head1 REFERENCE	250	=head1 REFERENCE
177		251
178	=head2 COMMAND LINE SWITCHES	252	=head2 COMMAND LINE SWITCHES
179		253
…		…
203	=back	277	=back
204		278
205	=cut	279	=cut
206		280
207	our %_IMG_CACHE;	281	our %_IMG_CACHE;
208	our %_ONCE_CACHE;
209	our $HOME;	282	our $HOME;
210	our ($self, $old, $new);	283	our ($self, $frame);
211	our ($x, $y, $w, $h);	284	our ($x, $y, $w, $h, $focus);
212		285
213	# enforce at least this interval between updates	286	# enforce at least this interval between updates
214	our $MIN_INTERVAL = 6/59.951;	287	our $MIN_INTERVAL = 6/59.951;
215		288
216	{	289	{
217	package urxvt::bgdsl; # background language	290	package urxvt::bgdsl; # background language
		291
		292	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
		293	sub FR_CACHE () { 1 } # cached values
		294	sub FR_AGAIN () { 2 } # what this expr is sensitive to
		295	sub FR_STATE () { 3 } # watchers etc.
218		296
219	use List::Util qw(min max sum shuffle);	297	use List::Util qw(min max sum shuffle);
220		298
221	=head2 PROVIDERS/GENERATORS	299	=head2 PROVIDERS/GENERATORS
222		300
…		…
229	=item load $path	307	=item load $path
230		308
231	Loads the image at the given C<$path>. The image is set to plane tiling	309	Loads the image at the given C<$path>. The image is set to plane tiling
232	mode.	310	mode.
233		311
234	Loaded images will be cached for one cycle.	312	If the image is already in memory (e.g. because another terminal instance
		313	uses it), then the in-memory copy is returned instead.
235		314
		315	=item load_uc $path
		316
		317	Load uncached - same as load, but does not cache the image, which means it
		318	is I<always> loaded from the filesystem again, even if another copy of it
		319	is in memory at the time.
		320
236	=cut	321	=cut
		322
		323	sub load_uc($) {
		324	$self->new_img_from_file ($_[0])
		325	}
237		326
238	sub load($) {	327	sub load($) {
239	my ($path) = @_;	328	my ($path) = @_;
240		329
241	$new->{load}{$path} = $old->{load}{$path} \|\| $self->new_img_from_file ($path);	330	$_IMG_CACHE{$path} \|\| do {
		331	my $img = load_uc $path;
		332	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		333	$img
		334	}
242	}	335	}
243		336
244	=item root	337	=item root
245		338
246	Returns the root window pixmap, that is, hopefully, the background image	339	Returns the root window pixmap, that is, hopefully, the background image
247	of your screen. The image is set to extend mode.	340	of your screen.
248		341
249	This function makes your expression root sensitive, that means it will be	342	This function makes your expression root sensitive, that means it will be
250	reevaluated when the bg image changes.	343	reevaluated when the bg image changes.
251		344
252	=cut	345	=cut
253		346
254	sub root() {	347	sub root() {
255	$new->{rootpmap_sensitive} = 1;	348	$frame->[FR_AGAIN]{rootpmap} = 1;
256	$self->new_img_from_root	349	$self->new_img_from_root
257	}	350	}
258		351
259	=item solid $colour	352	=item solid $colour
260		353
…		…
269	=cut	362	=cut
270		363
271	sub solid($;$$) {	364	sub solid($;$$) {
272	my $colour = pop;	365	my $colour = pop;
273		366
274	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	367	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
275	$img->fill ($colour);	368	$img->fill ($colour);
276	$img	369	$img
277	}	370	}
278		371
279	=item clone $img	372	=item clone $img
…		…
284	=cut	377	=cut
285		378
286	sub clone($) {	379	sub clone($) {
287	$_[0]->clone	380	$_[0]->clone
288	}	381	}
		382
		383	=item merge $img ...
		384
		385	Takes any number of images and merges them together, creating a single
		386	image containing them all. The tiling mode of the first image is used as
		387	the tiling mode of the resulting image.
		388
		389	This function is called automatically when an expression returns multiple
		390	images.
		391
		392	=cut
		393
		394	sub merge(@) {
		395	return $_[0] unless $#_;
		396
		397	# rather annoyingly clumsy, but optimisation is for another time
		398
		399	my $x0 = +1e9;
		400	my $y0 = +1e9;
		401	my $x1 = -1e9;
		402	my $y1 = -1e9;
		403
		404	for (@_) {
		405	my ($x, $y, $w, $h) = $_->geometry;
		406
		407	$x0 = $x if $x0 > $x;
		408	$y0 = $y if $y0 > $y;
		409
		410	$x += $w;
		411	$y += $h;
		412
		413	$x1 = $x if $x1 < $x;
		414	$y1 = $y if $y1 < $y;
		415	}
		416
		417	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		418	$base->repeat_mode ($_[0]->repeat_mode);
		419	$base->fill ([0, 0, 0, 0]);
		420
		421	$base->draw ($_)
		422	for @_;
		423
		424	$base
		425	}
		426
		427	=back
289		428
290	=head2 TILING MODES	429	=head2 TILING MODES
291		430
292	The following operators modify the tiling mode of an image, that is, the	431	The following operators modify the tiling mode of an image, that is, the
293	way that pixels outside the image area are painted when the image is used.	432	way that pixels outside the image area are painted when the image is used.
…		…
385		524
386	Return the X and Y coordinates of the terminal window (the terminal	525	Return the X and Y coordinates of the terminal window (the terminal
387	window is the full window by default, and the character area only when in	526	window is the full window by default, and the character area only when in
388	border-respect mode).	527	border-respect mode).
389		528
390	Using these functions make your expression sensitive to window moves.	529	Using these functions makes your expression sensitive to window moves.
391		530
392	These functions are mainly useful to align images to the root window.	531	These functions are mainly useful to align images to the root window.
393		532
394	Example: load an image and align it so it looks as if anchored to the	533	Example: load an image and align it so it looks as if anchored to the
395	background.	534	background (that's exactly what C<rootalign> does btw.):
396		535
397	move -TX, -TY, load "mybg.png"	536	move -TX, -TY, keep { load "mybg.png" }
398		537
399	=item TW	538	=item TW
		539
		540	=item TH
400		541
401	Return the width (C<TW>) and height (C<TH>) of the terminal window (the	542	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
402	terminal window is the full window by default, and the character area only	543	terminal window is the full window by default, and the character area only
403	when in border-respect mode).	544	when in border-respect mode).
404		545
405	Using these functions make your expression sensitive to window resizes.	546	Using these functions makes your expression sensitive to window resizes.
406		547
407	These functions are mainly useful to scale images, or to clip images to	548	These functions are mainly useful to scale images, or to clip images to
408	the window size to conserve memory.	549	the window size to conserve memory.
409		550
410	Example: take the screen background, clip it to the window size, blur it a	551	Example: take the screen background, clip it to the window size, blur it a
411	bit, align it to the window position and use it as background.	552	bit, align it to the window position and use it as background.
412		553
413	clip move -TX, -TY, blur 5, root	554	clip move -TX, -TY, keep { blur 5, root }
414		555
415	=cut	556	=item FOCUS
416		557
417	sub TX() { $new->{position_sensitive} = 1; $x }	558	Returns a boolean indicating whether the terminal window has keyboard
418	sub TY() { $new->{position_sensitive} = 1; $y }	559	focus, in which case it returns true.
419	sub TW() { $new->{size_sensitive} = 1; $w }	560
420	sub TH() { $new->{size_sensitive} = 1; $h }	561	Using this function makes your expression sensitive to focus changes.
		562
		563	A common use case is to fade the background image when the terminal loses
		564	focus, often together with the C<-fade> command line option. In fact,
		565	there is a special function for just that use case: C<focus_fade>.
		566
		567	Example: use two entirely different background images, depending on
		568	whether the window has focus.
		569
		570	FOCUS ? keep { load "has_focus.jpg" } : keep { load "no_focus.jpg" }
		571
		572	=cut
		573
		574	sub TX () { $frame->[FR_AGAIN]{position} = 1; $x }
		575	sub TY () { $frame->[FR_AGAIN]{position} = 1; $y }
		576	sub TW () { $frame->[FR_AGAIN]{size} = 1; $w }
		577	sub TH () { $frame->[FR_AGAIN]{size} = 1; $h }
		578	sub FOCUS() { $frame->[FR_AGAIN]{focus} = 1; $focus }
421		579
422	=item now	580	=item now
423		581
424	Returns the current time as (fractional) seconds since the epoch.	582	Returns the current time as (fractional) seconds since the epoch.
425		583
…		…
432	C<$seconds> seconds.	590	C<$seconds> seconds.
433		591
434	Example: load some image and rotate it according to the time of day (as if it were	592	Example: load some image and rotate it according to the time of day (as if it were
435	the hour pointer of a clock). Update this image every minute.	593	the hour pointer of a clock). Update this image every minute.
436		594
		595	again 60;
437	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"	596	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
438		597
439	=item counter $seconds	598	=item counter $seconds
440		599
441	Like C<again>, but also returns an increasing counter value, starting at	600	Like C<again>, but also returns an increasing counter value, starting at
442	0, which might be useful for some simple animation effects.	601	0, which might be useful for some simple animation effects.
…		…
444	=cut	603	=cut
445		604
446	sub now() { urxvt::NOW }	605	sub now() { urxvt::NOW }
447		606
448	sub again($) {	607	sub again($) {
449	$new->{again} = $_[0];	608	$frame->[FR_AGAIN]{time} = $_[0];
450	}	609	}
451		610
452	sub counter($) {	611	sub counter($) {
453	$new->{again} = $_[0];	612	$frame->[FR_AGAIN]{time} = $_[0];
454	$self->{counter} + 0	613	$frame->[FR_STATE]{counter} + 0
455	}	614	}
456		615
457	=back	616	=back
458		617
459	=head2 SHAPE CHANGING OPERATORS	618	=head2 SHAPE CHANGING OPERATORS
…		…
471	Clips an image to the given rectangle. If the rectangle is outside the	630	Clips an image to the given rectangle. If the rectangle is outside the
472	image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is	631	image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is
473	larger than the image, then the tiling mode defines how the extra pixels	632	larger than the image, then the tiling mode defines how the extra pixels
474	will be filled.	633	will be filled.
475		634
476	If C<$x> an C<$y> are missing, then C<0> is assumed for both.	635	If C<$x> and C<$y> are missing, then C<0> is assumed for both.
477		636
478	If C<$width> and C<$height> are missing, then the window size will be	637	If C<$width> and C<$height> are missing, then the window size will be
479	assumed.	638	assumed.
480		639
481	Example: load an image, blur it, and clip it to the window size to save	640	Example: load an image, blur it, and clip it to the window size to save
482	memory.	641	memory.
483		642
484	clip blur 10, load "mybg.png"	643	clip keep { blur 10, load "mybg.png" }
485		644
486	=cut	645	=cut
487		646
488	sub clip($;$$;$$) {	647	sub clip($;$$;$$) {
489	my $img = pop;	648	my $img = pop;
…		…
499	=item scale $width_factor, $height_factor, $img	658	=item scale $width_factor, $height_factor, $img
500		659
501	Scales the image by the given factors in horizontal	660	Scales the image by the given factors in horizontal
502	(C<$width>) and vertical (C<$height>) direction.	661	(C<$width>) and vertical (C<$height>) direction.
503		662
504	If only one factor is give, it is used for both directions.	663	If only one factor is given, it is used for both directions.
505		664
506	If no factors are given, scales the image to the window size without	665	If no factors are given, scales the image to the window size without
507	keeping aspect.	666	keeping aspect.
508		667
509	=item resize $width, $height, $img	668	=item resize $width, $height, $img
…		…
583	the terminal window (or the box specified by C<$width> and C<$height> if	742	the terminal window (or the box specified by C<$width> and C<$height> if
584	given).	743	given).
585		744
586	Example: load an image and center it.	745	Example: load an image and center it.
587		746
588	center pad load "mybg.png"	747	center keep { pad load "mybg.png" }
589		748
590	=item rootalign $img	749	=item rootalign $img
591		750
592	Moves the image so that it appears glued to the screen as opposed to the	751	Moves the image so that it appears glued to the screen as opposed to the
593	window. This gives the illusion of a larger area behind the window. It is	752	window. This gives the illusion of a larger area behind the window. It is
594	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	753	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
595	top left of the screen.	754	top left of the screen.
596		755
597	Example: load a background image, put it in mirror mode and root align it.	756	Example: load a background image, put it in mirror mode and root align it.
598		757
599	rootalign mirror load "mybg.png"	758	rootalign keep { mirror load "mybg.png" }
600		759
601	Example: take the screen background and align it, giving the illusion of	760	Example: take the screen background and align it, giving the illusion of
602	transparency as long as the window isn't in front of other windows.	761	transparency as long as the window isn't in front of other windows.
603		762
604	rootalign root	763	rootalign root
…		…
629		788
630	sub rootalign($) {	789	sub rootalign($) {
631	move -TX, -TY, $_[0]	790	move -TX, -TY, $_[0]
632	}	791	}
633		792
634	=item rotate $center_x, $center_y, $degrees, $new_width, $new_height	793	=item rotate $center_x, $center_y, $degrees, $img
635		794
636	Rotates the image by C<$degrees> degrees, counter-clockwise, around the	795	Rotates the image clockwise by C<$degrees> degrees, around the point at
637	pointer at C<$center_x> and C<$center_y> (specified as factor of image	796	C<$center_x> and C<$center_y> (specified as factor of image width/height).
638	width/height), generating a new image with width C<$new_width> and height
639	C<$new_height>.
640		797
641	#TODO# new width, height, maybe more operators?
642
643	Example: rotate the image by 90 degrees	798	Example: rotate the image by 90 degrees around its center.
644		799
645	=cut	800	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
646		801
		802	=cut
		803
647	sub rotate($$$$$$) {	804	sub rotate($$$$) {
648	my $img = pop;	805	my $img = pop;
649	$img->rotate (	806	$img->rotate (
650	$_[0] * $img->w,	807	$_[0] * ($img->w + $img->x),
651	$_[1] * $img->h,	808	$_[1] * ($img->h + $img->y),
652	$_[2] * (3.14159265 / 180),	809	$_[2] * (3.14159265 / 180),
653	$_[3],
654	$_[4],
655	)	810	)
656	}	811	}
657		812
658	=back	813	=back
659		814
660	=head2 COLOUR MODIFICATIONS	815	=head2 COLOUR MODIFICATIONS
661		816
662	The following operators change the pixels of the image.	817	The following operators change the pixels of the image.
663		818
664	=over 4	819	=over 4
		820
		821	=item tint $color, $img
		822
		823	Tints the image in the given colour.
		824
		825	Example: tint the image red.
		826
		827	tint "red", load "rgb.png"
		828
		829	Example: the same, but specify the colour by component.
		830
		831	tint [1, 0, 0], load "rgb.png"
		832
		833	=cut
		834
		835	sub tint($$) {
		836	$_[1]->tint ($_[0])
		837	}
		838
		839	=item shade $factor, $img
		840
		841	Shade the image by the given factor.
		842
		843	=cut
		844
		845	sub shade($$) {
		846	$_[1]->shade ($_[0])
		847	}
665		848
666	=item contrast $factor, $img	849	=item contrast $factor, $img
667		850
668	=item contrast $r, $g, $b, $img	851	=item contrast $r, $g, $b, $img
669		852
…		…
699	latter in a white picture.	882	latter in a white picture.
700		883
701	Due to idiosyncrasies in the underlying XRender extension, biases less	884	Due to idiosyncrasies in the underlying XRender extension, biases less
702	than zero can be I<very> slow.	885	than zero can be I<very> slow.
703		886
		887	You can also try the experimental(!) C<muladd> operator.
		888
704	=cut	889	=cut
705		890
706	sub contrast($$;$$;$) {	891	sub contrast($$;$$;$) {
707	my $img = pop;	892	my $img = pop;
708	my ($r, $g, $b, $a) = @_;	893	my ($r, $g, $b, $a) = @_;
…		…
723	$a = 1 if @_ < 4;	908	$a = 1 if @_ < 4;
724		909
725	$img = $img->clone;	910	$img = $img->clone;
726	$img->brightness ($r, $g, $b, $a);	911	$img->brightness ($r, $g, $b, $a);
727	$img	912	$img
		913	}
		914
		915	=item muladd $mul, $add, $img # EXPERIMENTAL
		916
		917	First multiplies the pixels by C<$mul>, then adds C<$add>. This can be used
		918	to implement brightness and contrast at the same time, with a wider value
		919	range than contrast and brightness operators.
		920
		921	Due to numerous bugs in XRender implementations, it can also introduce a
		922	number of visual artifacts.
		923
		924	Example: increase contrast by a factor of C<$c> without changing image
		925	brightness too much.
		926
		927	muladd $c, (1 - $c) * 0.5, $img
		928
		929	=cut
		930
		931	sub muladd($$$) {
		932	$_[2]->muladd ($_[0], $_[1])
728	}	933	}
729		934
730	=item blur $radius, $img	935	=item blur $radius, $img
731		936
732	=item blur $radius_horz, $radius_vert, $img	937	=item blur $radius_horz, $radius_vert, $img
…		…
744	sub blur($$;$) {	949	sub blur($$;$) {
745	my $img = pop;	950	my $img = pop;
746	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	951	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
747	}	952	}
748		953
		954	=item focus_fade $img
		955
		956	=item focus_fade $factor, $img
		957
		958	=item focus_fade $factor, $color, $img
		959
		960	Fades the image by the given factor (and colour) when focus is lost (the
		961	same as the C<-fade>/C<-fadecolor> command line options, which also supply
		962	the default values for C<factor> and C<$color>. Unlike with C<-fade>, the
		963	C<$factor> is a real value, not a percentage value (that is, 0..1, not
		964	0..100).
		965
		966	Example: do the right thing when focus fading is requested.
		967
		968	focus_fade load "mybg.jpg";
		969
		970	=cut
		971
		972	sub focus_fade($;$$) {
		973	my $img = pop;
		974
		975	return $img
		976	if FOCUS;
		977
		978	my $fade = @_ >= 1 ? $_[0] : defined $self->resource ("fade") ? $self->resource ("fade") * 0.01 : 0;
		979	my $color = @_ >= 2 ? $_[1] : $self->resource ("color+" . urxvt::Color_fade);
		980
		981	$img = $img->tint ($color) if $color ne "rgb:00/00/00";
		982	$img = $img->muladd (1 - $fade, 0) if $fade;
		983
		984	$img
		985	}
		986
749	=back	987	=back
750		988
751	=head2 OTHER STUFF	989	=head2 OTHER STUFF
752		990
753	Anything that didn't fit any of the other categories, even after appliyng	991	Anything that didn't fit any of the other categories, even after applying
754	force and closing our eyes.	992	force and closing our eyes.
755		993
756	=over 4	994	=over 4
757		995
758	=item once { ... }	996	=item keep { ... }
759		997
760	This function takes a code block as argument, that is, one or more	998	This operator takes a code block as argument, that is, one or more
761	statements enclosed by braces.	999	statements enclosed by braces.
762		1000
763	The trick is that this code block is only evaluated once - future calls	1001	The trick is that this code block is only evaluated when the outcome
764	will simply return the original image (yes, it should only be used with	1002	changes - on other calls the C<keep> simply returns the image it computed
765	images).	1003	previously (yes, it should only be used with images). Or in other words,
		1004	C<keep> I<caches> the result of the code block so it doesn't need to be
		1005	computed again.
766		1006
767	This can be extremely useful to avoid redoign the same slow operations	1007	This can be extremely useful to avoid redoing slow operations - for
768	again and again- for example, if your background expression takes the root	1008	example, if your background expression takes the root background, blurs it
769	background, blurs it and then root-aligns it it would have to blur the	1009	and then root-aligns it it would have to blur the root background on every
770	root background on every window move or resize.	1010	window move or resize.
771		1011
		1012	Another example is C<load>, which can be quite slow.
		1013
		1014	In fact, urxvt itself encloses the whole expression in some kind of
		1015	C<keep> block so it only is reevaluated as required.
		1016
772	Putting the blur into a C<once> block will make sure the blur is only done	1017	Putting the blur into a C<keep> block will make sure the blur is only done
773	once:	1018	once, while the C<rootalign> is still done each time the window moves.
774		1019
775	rootlign once { blur 10, root }	1020	rootalign keep { blur 10, root }
776		1021
777	This leaves the question of how to force reevaluation of the block, in	1022	This leaves the question of how to force reevaluation of the block,
778	case the root background changes: Right now, all once blocks forget that	1023	in case the root background changes: If expression inside the block
779	they ahve been executed before each time the root background changes (if	1024	is sensitive to some event (root background changes, window geometry
780	the expression is sensitive to that) or when C<once_again> is called.	1025	changes), then it will be reevaluated automatically as needed.
781		1026
782	=item once_again
783
784	Resets all C<once> block as if they had never been called, i.e. on the
785	next call they will be reevaluated again.
786
787	=cut	1027	=cut
788		1028
789	sub once(&) {	1029	sub keep(&) {
790	$_ONCE_CACHE{$_[0]+0} \|\|= $_[0]()	1030	my $id = $_[0]+0;
		1031
		1032	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		1033
		1034	unless ($frame->[FR_CACHE]) {
		1035	$frame->[FR_CACHE] = [ $_[0]() ];
		1036
		1037	my $self = $self;
		1038	my $frame = $frame;
		1039	Scalar::Util::weaken $frame;
		1040	$self->compile_frame ($frame, sub {
		1041	# clear this frame cache, also for all parents
		1042	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		1043	undef $frame->[FR_CACHE];
		1044	}
		1045
		1046	$self->recalculate;
		1047	});
		1048	};
		1049
		1050	# in scalar context we always return the first original result, which
		1051	# is not quite how perl works.
		1052	wantarray
		1053	? @{ $frame->[FR_CACHE] }
		1054	: $frame->[FR_CACHE][0]
		1055	}
		1056
		1057	# sub keep_clear() {
		1058	# delete $self->{frame_cache};
791	}	1059	# }
792
793	sub once_again() {
794	%_ONCE_CACHE = ();
795	}
796		1060
797	=back	1061	=back
798		1062
799	=cut	1063	=cut
800		1064
801	}	1065	}
802		1066
803	sub parse_expr {	1067	sub parse_expr {
804	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	1068	my $expr = eval
		1069	"sub {\n"
		1070	. "package urxvt::bgdsl;\n"
		1071	. "#line 0 'background expression'\n"
		1072	. "$_[0]\n"
		1073	. "}";
805	die if $@;	1074	die if $@;
806	$expr	1075	$expr
807	}	1076	}
808		1077
809	# compiles a parsed expression	1078	# compiles a parsed expression
810	sub set_expr {	1079	sub set_expr {
811	my ($self, $expr) = @_;	1080	my ($self, $expr) = @_;
812		1081
		1082	$self->{root} = []; # the outermost frame
813	$self->{expr} = $expr;	1083	$self->{expr} = $expr;
814	$self->recalculate;	1084	$self->recalculate;
		1085	}
		1086
		1087	# takes a hash of sensitivity indicators and installs watchers
		1088	sub compile_frame {
		1089	my ($self, $frame, $cb) = @_;
		1090
		1091	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		1092	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		1093
		1094	# don't keep stuff alive
		1095	Scalar::Util::weaken $state;
		1096
		1097	if ($again->{nested}) {
		1098	$state->{nested} = 1;
		1099	} else {
		1100	delete $state->{nested};
		1101	}
		1102
		1103	if (my $interval = $again->{time}) {
		1104	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		1105	if $state->{time}[0] != $interval;
		1106
		1107	# callback might have changed, although we could just rule that out
		1108	$state->{time}[1]->cb (sub {
		1109	++$state->{counter};
		1110	$cb->();
		1111	});
		1112	} else {
		1113	delete $state->{time};
		1114	}
		1115
		1116	if ($again->{position}) {
		1117	$state->{position} = $self->on (position_change => $cb);
		1118	} else {
		1119	delete $state->{position};
		1120	}
		1121
		1122	if ($again->{size}) {
		1123	$state->{size} = $self->on (size_change => $cb);
		1124	} else {
		1125	delete $state->{size};
		1126	}
		1127
		1128	if ($again->{rootpmap}) {
		1129	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		1130	} else {
		1131	delete $state->{rootpmap};
		1132	}
		1133
		1134	if ($again->{focus}) {
		1135	$state->{focus} = $self->on (focus_in => $cb, focus_out => $cb);
		1136	} else {
		1137	delete $state->{focus};
		1138	}
815	}	1139	}
816		1140
817	# evaluate the current bg expression	1141	# evaluate the current bg expression
818	sub recalculate {	1142	sub recalculate {
819	my ($arg_self) = @_;	1143	my ($arg_self) = @_;
…		…
829		1153
830	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1154	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
831		1155
832	# set environment to evaluate user expression	1156	# set environment to evaluate user expression
833		1157
834	local $self = $arg_self;	1158	local $self = $arg_self;
835
836	local $HOME = $ENV{HOME};	1159	local $HOME = $ENV{HOME};
837	local $old = $self->{state};	1160	local $frame = $self->{root};
838	local $new = my $state = $self->{state} = {};
839		1161
840	($x, $y, $w, $h) =
841	$self->background_geometry ($self->{border});	1162	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
		1163	$focus = $self->focus;
842		1164
843	# evaluate user expression	1165	# evaluate user expression
844		1166
845	my $img = eval { $self->{expr}->() };	1167	my @img = eval { $self->{expr}->() };
846	warn $@ if $@;#d#	1168	die $@ if $@;
847	die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";	1169	die "background-expr did not return anything.\n" unless @img;
		1170	die "background-expr: expected image(s), got something else.\n"
		1171	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
848		1172
849	$state->{size_sensitive} = 1	1173	my $img = urxvt::bgdsl::merge @img;
		1174
		1175	$frame->[FR_AGAIN]{size} = 1
850	if $img->repeat_mode != urxvt::RepeatNormal;	1176	if $img->repeat_mode != urxvt::RepeatNormal;
851		1177
852	# if the expression is sensitive to external events, prepare reevaluation then	1178	# if the expression is sensitive to external events, prepare reevaluation then
853		1179	$self->compile_frame ($frame, sub { $arg_self->recalculate });
854	my $repeat;
855
856	if (my $again = $state->{again}) {
857	$repeat = 1;
858	my $self = $self;
859	$state->{timer} = $again == $old->{again}
860	? $old->{timer}
861	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
862	++$self->{counter};
863	$self->recalculate
864	});
865	}
866
867	if (delete $state->{position_sensitive}) {
868	$repeat = 1;
869	$self->enable (position_change => sub { $_[0]->recalculate });
870	} else {
871	$self->disable ("position_change");
872	}
873
874	if (delete $state->{size_sensitive}) {
875	$repeat = 1;
876	$self->enable (size_change => sub { $_[0]->recalculate });
877	} else {
878	$self->disable ("size_change");
879	}
880
881	if (delete $state->{rootpmap_sensitive}) {
882	$repeat = 1;
883	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
884	} else {
885	$self->disable ("rootpmap_change");
886	}
887		1180
888	# clear stuff we no longer need	1181	# clear stuff we no longer need
889		1182
890	%$old = ();	1183	# unless (%{ $frame->[FR_STATE] }) {
891
892	unless ($repeat) {
893	delete $self->{state};	1184	# delete $self->{state};
894	delete $self->{expr};	1185	# delete $self->{expr};
895	}	1186	# }
896		1187
897	# set background pixmap	1188	# set background pixmap
898		1189
899	$self->set_background ($img, $self->{border});	1190	$self->set_background ($img, $self->{border});
900	$self->scr_recolour (0);	1191	$self->scr_recolor (0);
901	$self->want_refresh;	1192	$self->want_refresh;
902	}	1193	}
903		1194
904	sub on_start {	1195	sub on_start {
905	my ($self) = @_;	1196	my ($self) = @_;

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.52 by root, Tue Jun 12 10:45:53 2012 UTC vs. Revision 1.91 by sf-exg, Thu Jul 7 17:38:34 2016 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.52 by root, Tue Jun 12 10:45:53 2012 UTC vs.
Revision 1.91 by sf-exg, Thu Jul 7 17:38:34 2016 UTC