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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.49 by root, Sun Jun 10 15:29:18 2012 UTC vs.
Revision 1.77 by root, Tue Sep 4 11:21:11 2012 UTC

…		…
2		2
3	#:META:X_RESOURCE:%.expr:string:background expression	3	#:META:X_RESOURCE:%.expr:string:background expression
4	#:META:X_RESOURCE:%.border:boolean:respect the terminal border	4	#:META:X_RESOURCE:%.border:boolean:respect the terminal border
5	#:META:X_RESOURCE:%.interval:seconds:minimum time between updates	5	#:META:X_RESOURCE:%.interval:seconds:minimum time between updates
6		6
7	#TODO: once, rootalign
8
9	=head1 NAME	7	=head1 NAME
10		8
11	background - manage terminal background	9	background - manage terminal background
12		10
13	=head1 SYNOPSIS	11	=head1 SYNOPSIS
14		12
15	urxvt --background-expr 'background expression'	13	urxvt --background-expr 'background expression'
16	--background-border	14	--background-border
17	--background-interval seconds	15	--background-interval seconds
18		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
19	=head1 DESCRIPTION	41	=head1 DESCRIPTION
20		42
21	This extension manages the terminal background by creating a picture that	43	This extension manages the terminal background by creating a picture that
22	is behind the text, replacing the normal background colour.	44	is behind the text, replacing the normal background colour.
23		45
…		…
28	to be as simple as possible.	50	to be as simple as possible.
29		51
30	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
31	use:	53	use:
32		54
33	urxvt --background-expr 'scale load "/path/to/mybg.png"'	55	urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
34		56
35	Or specified as a X resource:	57	Or specified as a X resource:
36		58
37	URxvt.background-expr: scale load "/path/to/mybg.png"	59	URxvt.background-expr: scale keep { load "/path/to/mybg.png" }
38		60
39	=head1 THEORY OF OPERATION	61	=head1 THEORY OF OPERATION
40		62
41	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
42	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
…		…
55	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
56	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
57	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
58	timer elapses), then the expression will be evaluated again.	80	timer elapses), then the expression will be evaluated again.
59		81
60	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"
61	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
62	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
63	example. That ensures that the picture always fills the terminal, even	85	example. That ensures that the picture always fills the terminal, even
64	after it's size changes.	86	after its size changes.
65		87
66	=head2 EXPRESSIONS	88	=head2 EXPRESSIONS
67		89
68	Expressions are normal Perl expressions, in fact, they are Perl blocks -	90	Expressions are normal Perl expressions, in fact, they are Perl blocks -
69	which means you could use multiple lines and statements:	91	which means you could use multiple lines and statements:
70		92
		93	scale keep {
71	again 3600;	94	again 3600;
72	if (localtime now)[6]) {	95	if (localtime now)[6]) {
73	return scale load "$HOME/weekday.png";	96	return load "$HOME/weekday.png";
74	} else {	97	} else {
75	return scale load "$HOME/sunday.png";	98	return load "$HOME/sunday.png";
		99	}
76	}	100	}
77		101
78	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
79	background on Sundays, and F<weekday.png> on all other days.	104	Sundays, and F<weekday.png> on all other days.
80		105
81	Fortunately, we expect that most expressions will be much simpler, with	106	Fortunately, we expect that most expressions will be much simpler, with
82	little Perl knowledge needed.	107	little Perl knowledge needed.
83		108
84	Basically, you always start with a function that "generates" an image	109	Basically, you always start with a function that "generates" an image
…		…
117	horizontal and vertical dimensions. For example, this halves the image	142	horizontal and vertical dimensions. For example, this halves the image
118	width and doubles the image height:	143	width and doubles the image height:
119		144
120	scale 0.5, 2, load "$HOME/mypic.png"	145	scale 0.5, 2, load "$HOME/mypic.png"
121		146
122	Other effects than scalign are also readily available, for exmaple, you can	147	IF you try out these expressions, you might suffer from some sluggishness,
123	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:
124		151
		152	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		153
		154	The C<keep> operator executes all the statements inside the braces only
		155	once, or when it thinks the outcome might change. In other cases it
		156	returns the last value computed by the brace block.
		157
		158	This means that the C<load> is only executed once, which makes it much
		159	faster, but also means that more memory is being used, because the loaded
		160	image must be kept in memory at all times. In this expression, the
		161	trade-off is likely worth it.
		162
		163	But back to effects: Other effects than scaling are also readily
		164	available, for example, you can tile the image to fill the whole window,
		165	instead of resizing it:
		166
125	tile load "$HOME/mypic.png"	167	tile keep { load "$HOME/mypic.png" }
126		168
127	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator	169	In fact, images returned by C<load> are in C<tile> mode by default, so the
128	is kind of superfluous.	170	C<tile> operator is kind of superfluous.
129		171
130	Another common effect is to mirror the image, so that the same edges touch:	172	Another common effect is to mirror the image, so that the same edges
		173	touch:
131		174
132	mirror load "$HOME/mypic.png"	175	mirror keep { load "$HOME/mypic.png" }
133		176
134	This is also a typical background expression:	177	Another common background expression is:
135		178
136	rootalign root	179	rootalign root
137		180
138	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
139	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
140	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:
141	moved around.	184	the image seems to be static while the window is moved around.
142		185
143	=head2 CYCLES AND CACHING	186	=head2 COLOUR SPECIFICATIONS
144		187
145	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
146	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:
147	have begun. Many operators cache their results till the next cycle.
148		190
149	For example, the C<load> operator keeps a copy of the image. If it is	191	"red" # named colour
150	asked to load the same image on the next cycle it will not load it again,	192	"#f00" # simple rgb
151	but return the cached copy.	193	"[50]red" # red with 50% alpha
		194	"TekHVC:300/50/50" # anything goes
152		195
153	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:
154	image every time, it will always be cached, but when you load a different
155	image, it will forget about the first one.
156		197
157	This allows you to either speed things up by keeping multiple images in	198	[0.5] # 50% gray, 100% alpha
158	memory, or comserve 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
159		201
160	For example, you can keep two images in memory and use a random one like	202	=head2 CACHING AND SENSITIVITY
161	this:
162		203
163	my $img1 = load "img1.png";	204	Since some operations (such as C<load> and C<blur>) can take a long time,
164	my $img2 = load "img2.png";	205	caching results can be very important for a smooth operation. Caching can
165	(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.
166		209
167	Since both images are "loaded" every time the expression is evaluated,	210	=head3 C<keep { ... }> caching
168	they are always kept in memory. Contrast this version:
169		211
170	my $path1 = "img1.png";	212	The most important way to cache expensive operations is to use C<keep {
171	my $path2 = "img2.png";	213	... }>. The C<keep> operator takes a block of multiple statements enclosed
172	load ((0.5 > rand) ? $path1 : $path2)	214	by C<{}> and keeps the return value in memory.
173		215
174	Here, a path is selected randomly, and load is only called for one image,	216	An expression can be "sensitive" to various external events, such as
175	so keeps only one image in memory. If, on the next evaluation, luck	217	scaling or moving the window, root background changes and timers. Simply
176	decides to use the other path, then it will have to load that image again.	218	using an expression (such as C<scale> without parameters) that depends on
		219	certain changing values (called "variables"), or using those variables
		220	directly, will make an expression sensitive to these events - for example,
		221	using C<scale> or C<TW> will make the expression sensitive to the terminal
		222	size, and thus to resizing events.
		223
		224	When such an event happens, C<keep> will automatically trigger a
		225	reevaluation of the whole expression with the new value of the expression.
		226
		227	C<keep> is most useful for expensive operations, such as C<blur>:
		228
		229	rootalign keep { blur 20, root }
		230
		231	This makes a blurred copy of the root background once, and on subsequent
		232	calls, just root-aligns it. Since C<blur> is usually quite slow and
		233	C<rootalign> is quite fast, this trades extra memory (for the cached
		234	blurred pixmap) with speed (blur only needs to be redone when root
		235	changes).
		236
		237	=head3 C<load> caching
		238
		239	The C<load> operator itself does not keep images in memory, but as long as
		240	the image is still in memory, C<load> will use the in-memory image instead
		241	of loading it freshly from disk.
		242
		243	That means that this expression:
		244
		245	keep { load "$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.
177		249
178	=head1 REFERENCE	250	=head1 REFERENCE
179		251
180	=head2 COMMAND LINE SWITCHES	252	=head2 COMMAND LINE SWITCHES
181		253
…		…
193	Specifying this flag changes the behaviour, so that the image only	265	Specifying this flag changes the behaviour, so that the image only
194	replaces the background of the character area.	266	replaces the background of the character area.
195		267
196	=item --background-interval seconds	268	=item --background-interval seconds
197		269
198	Since some operations in the underlying XRender extension can effetively	270	Since some operations in the underlying XRender extension can effectively
199	freeze your X-server for prolonged time, this extension enforces a minimum	271	freeze your X-server for prolonged time, this extension enforces a minimum
200	time between updates, which is normally about 0.1 seconds.	272	time between updates, which is normally about 0.1 seconds.
201		273
202	If you want to do updates more often, you can decrease this safety	274	If you want to do updates more often, you can decrease this safety
203	interval with this switch.	275	interval with this switch.
204		276
205	=back	277	=back
206		278
207	=cut	279	=cut
208		280
209	our %_IMGCACHE;	281	our %_IMG_CACHE;
210	our $HOME;	282	our $HOME;
211	our ($self, $old, $new);	283	our ($self, $frame);
212	our ($x, $y, $w, $h);	284	our ($x, $y, $w, $h);
213		285
214	# enforce at least this interval between updates	286	# enforce at least this interval between updates
215	our $MIN_INTERVAL = 6/59.951;	287	our $MIN_INTERVAL = 6/59.951;
216		288
217	{	289	{
218	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.
219		296
220	use List::Util qw(min max sum shuffle);	297	use List::Util qw(min max sum shuffle);
221		298
222	=head2 PROVIDERS/GENERATORS	299	=head2 PROVIDERS/GENERATORS
223		300
…		…
230	=item load $path	307	=item load $path
231		308
232	Loads the image at the given C<$path>. The image is set to plane tiling	309	Loads the image at the given C<$path>. The image is set to plane tiling
233	mode.	310	mode.
234		311
235	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 us returned instead.
236		314
		315	=item load_uc $path
		316
		317	Load uncached - same as load, but does not cache the image, which means it
		318	is I<always> loaded from the filesystem again, even if another copy of it
		319	is in memory at the time.
		320
237	=cut	321	=cut
		322
		323	sub load_uc($) {
		324	$self->new_img_from_file ($_[0])
		325	}
238		326
239	sub load($) {	327	sub load($) {
240	my ($path) = @_;	328	my ($path) = @_;
241		329
242	$new->{load}{$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	}
243	}	335	}
244		336
245	=item root	337	=item root
246		338
247	Returns the root window pixmap, that is, hopefully, the background image	339	Returns the root window pixmap, that is, hopefully, the background image
248	of your screen. The image is set to extend mode.	340	of your screen.
249		341
250	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
251	reevaluated when the bg image changes.	343	reevaluated when the bg image changes.
252		344
253	=cut	345	=cut
254		346
255	sub root() {	347	sub root() {
256	$new->{rootpmap_sensitive} = 1;	348	$frame->[FR_AGAIN]{rootpmap} = 1;
257	die "root op not supported, exg, we need you";	349	$self->new_img_from_root
258	}	350	}
259		351
260	=item solid $colour	352	=item solid $colour
261		353
262	=item solid $width, $height, $colour	354	=item solid $width, $height, $colour
…		…
270	=cut	362	=cut
271		363
272	sub solid($;$$) {	364	sub solid($;$$) {
273	my $colour = pop;	365	my $colour = pop;
274		366
275	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);
276	$img->fill ($colour);	368	$img->fill ($colour);
277	$img	369	$img
278	}	370	}
279		371
280	=item clone $img	372	=item clone $img
…		…
284		376
285	=cut	377	=cut
286		378
287	sub clone($) {	379	sub clone($) {
288	$_[0]->clone	380	$_[0]->clone
		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
289	}	425	}
290		426
291	=back	427	=back
292		428
293	=head2 TILING MODES	429	=head2 TILING MODES
…		…
326	become transparent. This mode is most useful when you want to place an	462	become transparent. This mode is most useful when you want to place an
327	image over another image or the background colour while leaving all	463	image over another image or the background colour while leaving all
328	background pixels outside the image unchanged.	464	background pixels outside the image unchanged.
329		465
330	Example: load an image and display it in the upper left corner. The rest	466	Example: load an image and display it in the upper left corner. The rest
331	of the space is left "empty" (transparent or wahtever your compisotr does	467	of the space is left "empty" (transparent or whatever your compositor does
332	in alpha mode, else background colour).	468	in alpha mode, else background colour).
333		469
334	pad load "mybg.png"	470	pad load "mybg.png"
335		471
336	=item extend $img	472	=item extend $img
337		473
338	Extends the image over the whole plane, using the closest pixel in the	474	Extends the image over the whole plane, using the closest pixel in the
339	area outside the image. This mode is mostly useful when you more complex	475	area outside the image. This mode is mostly useful when you use more complex
340	filtering operations and want the pixels outside the image to have the	476	filtering operations and want the pixels outside the image to have the
341	same values as the pixels near the edge.	477	same values as the pixels near the edge.
342		478
343	Example: just for curiosity, how does this pixel extension stuff work?	479	Example: just for curiosity, how does this pixel extension stuff work?
344		480
…		…
393	Using these functions make your expression sensitive to window moves.	529	Using these functions make your expression sensitive to window moves.
394		530
395	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.
396		532
397	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
398	background.	534	background (that's exactly what C<rootalign> does btw.):
399		535
400	move -TX, -TY, load "mybg.png"	536	move -TX, -TY, keep { load "mybg.png" }
401		537
402	=item TW	538	=item TW
		539
		540	=item TH
403		541
404	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
405	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
406	when in border-respect mode).	544	when in border-respect mode).
407		545
…		…
411	the window size to conserve memory.	549	the window size to conserve memory.
412		550
413	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
414	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.
415		553
416	clip move -TX, -TY, blur 5, root	554	clip move -TX, -TY, keep { blur 5, root }
417		555
418	=cut	556	=cut
419		557
420	sub TX() { $new->{position_sensitive} = 1; $x }	558	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
421	sub TY() { $new->{position_sensitive} = 1; $y }	559	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
422	sub TW() { $new->{size_sensitive} = 1; $w }	560	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
423	sub TH() { $new->{size_sensitive} = 1; $h }	561	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
424		562
425	=item now	563	=item now
426		564
427	Returns the current time as (fractional) seconds since the epoch.	565	Returns the current time as (fractional) seconds since the epoch.
428		566
…		…
435	C<$seconds> seconds.	573	C<$seconds> seconds.
436		574
437	Example: load some image and rotate it according to the time of day (as if it were	575	Example: load some image and rotate it according to the time of day (as if it were
438	the hour pointer of a clock). Update this image every minute.	576	the hour pointer of a clock). Update this image every minute.
439		577
		578	again 60;
440	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"	579	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
441		580
442	=item counter $seconds	581	=item counter $seconds
443		582
444	Like C<again>, but also returns an increasing counter value, starting at	583	Like C<again>, but also returns an increasing counter value, starting at
445	0, which might be useful for some simple animation effects.	584	0, which might be useful for some simple animation effects.
…		…
447	=cut	586	=cut
448		587
449	sub now() { urxvt::NOW }	588	sub now() { urxvt::NOW }
450		589
451	sub again($) {	590	sub again($) {
452	$new->{again} = $_[0];	591	$frame->[FR_AGAIN]{time} = $_[0];
453	}	592	}
454		593
455	sub counter($) {	594	sub counter($) {
456	$new->{again} = $_[0];	595	$frame->[FR_AGAIN]{time} = $_[0];
457	$self->{counter} + 0	596	$frame->[FR_STATE]{counter} + 0
458	}	597	}
459		598
460	=back	599	=back
461		600
462	=head2 SHAPE CHANGING OPERATORS	601	=head2 SHAPE CHANGING OPERATORS
…		…
482	assumed.	621	assumed.
483		622
484	Example: load an image, blur it, and clip it to the window size to save	623	Example: load an image, blur it, and clip it to the window size to save
485	memory.	624	memory.
486		625
487	clip blur 10, load "mybg.png"	626	clip keep { blur 10, load "mybg.png" }
488		627
489	=cut	628	=cut
490		629
491	sub clip($;$$;$$) {	630	sub clip($;$$;$$) {
492	my $img = pop;	631	my $img = pop;
…		…
586	the terminal window (or the box specified by C<$width> and C<$height> if	725	the terminal window (or the box specified by C<$width> and C<$height> if
587	given).	726	given).
588		727
589	Example: load an image and center it.	728	Example: load an image and center it.
590		729
591	center pad load "mybg.png"	730	center keep { pad load "mybg.png" }
592		731
593	=item rootalign $img	732	=item rootalign $img
594		733
595	Moves the image so that it appears glued to the screen as opposed to the	734	Moves the image so that it appears glued to the screen as opposed to the
596	window. This gives the illusion of a larger area behind the window. It is	735	window. This gives the illusion of a larger area behind the window. It is
597	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	736	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
598	top left of the screen.	737	top left of the screen.
599		738
600	Example: load a background image, put it in mirror mode and root align it.	739	Example: load a background image, put it in mirror mode and root align it.
601		740
602	rootalign mirror load "mybg.png"	741	rootalign keep { mirror load "mybg.png" }
603		742
604	Example: take the screen background and align it, giving the illusion of	743	Example: take the screen background and align it, giving the illusion of
605	transparency as long as the window isn't in front of other windows.	744	transparency as long as the window isn't in front of other windows.
606		745
607	rootalign root	746	rootalign root
…		…
632		771
633	sub rootalign($) {	772	sub rootalign($) {
634	move -TX, -TY, $_[0]	773	move -TX, -TY, $_[0]
635	}	774	}
636		775
		776	=item rotate $center_x, $center_y, $degrees, $img
		777
		778	Rotates the image clockwise by C<$degrees> degrees, around the point at
		779	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		780
		781	Example: rotate the image by 90 degrees around it's center.
		782
		783	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		784
		785	=cut
		786
		787	sub rotate($$$$) {
		788	my $img = pop;
		789	$img->rotate (
		790	$_[0] * ($img->w + $img->x),
		791	$_[1] * ($img->h + $img->y),
		792	$_[2] * (3.14159265 / 180),
		793	)
		794	}
		795
637	=back	796	=back
638		797
639	=head2 COLOUR MODIFICATIONS	798	=head2 COLOUR MODIFICATIONS
640		799
641	The following operators change the pixels of the image.	800	The following operators change the pixels of the image.
642		801
643	=over 4	802	=over 4
		803
		804	=item tint $color, $img
		805
		806	Tints the image in the given colour.
		807
		808	Example: tint the image red.
		809
		810	tint "red", load "rgb.png"
		811
		812	Example: the same, but specify the colour by component.
		813
		814	tint [1, 0, 0], load "rgb.png"
		815
		816	=cut
		817
		818	sub tint($$) {
		819	$_[1]->tint ($_[0])
		820	}
644		821
645	=item contrast $factor, $img	822	=item contrast $factor, $img
646		823
647	=item contrast $r, $g, $b, $img	824	=item contrast $r, $g, $b, $img
648		825
…		…
675		852
676	Values less than 0 reduce brightness, while values larger than 0 increase	853	Values less than 0 reduce brightness, while values larger than 0 increase
677	it. Useful range is from -1 to 1 - the former results in a black, the	854	it. Useful range is from -1 to 1 - the former results in a black, the
678	latter in a white picture.	855	latter in a white picture.
679		856
680	Due to idiosynchrasies in the underlying XRender extension, biases less	857	Due to idiosyncrasies in the underlying XRender extension, biases less
681	than zero can be I<very> slow.	858	than zero can be I<very> slow.
		859
		860	You can also try the experimental(!) C<muladd> operator.
682		861
683	=cut	862	=cut
684		863
685	sub contrast($$;$$;$) {	864	sub contrast($$;$$;$) {
686	my $img = pop;	865	my $img = pop;
…		…
702	$a = 1 if @_ < 4;	881	$a = 1 if @_ < 4;
703		882
704	$img = $img->clone;	883	$img = $img->clone;
705	$img->brightness ($r, $g, $b, $a);	884	$img->brightness ($r, $g, $b, $a);
706	$img	885	$img
		886	}
		887
		888	=item muladd $mul, $add, $img # EXPERIMENTAL
		889
		890	First multipliesthe pixels by C<$mul>, then adds C<$add>. This cna be used
		891	to implement brightness and contrast at the same time, with a wider value
		892	range than contrast and brightness operators.
		893
		894	Due to numerous bugs in XRender implementations, it can also introduce a
		895	number of visual artifacts.
		896
		897	Example: increase contrast by a factor of C<$c> without changing image
		898	brightness too much.
		899
		900	muladd $c, (1 - $c) * 0.5, $img
		901
		902	=cut
		903
		904	sub muladd($$$) {
		905	$_[2]->muladd ($_[0], $_[1])
707	}	906	}
708		907
709	=item blur $radius, $img	908	=item blur $radius, $img
710		909
711	=item blur $radius_horz, $radius_vert, $img	910	=item blur $radius_horz, $radius_vert, $img
…		…
723	sub blur($$;$) {	922	sub blur($$;$) {
724	my $img = pop;	923	my $img = pop;
725	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	924	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
726	}	925	}
727		926
728	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
729
730	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
731	pointer at C<$center_x> and C<$center_y> (specified as factor of image
732	width/height), generating a new image with width C<$new_width> and height
733	C<$new_height>.
734
735	#TODO# new width, height, maybe more operators?
736
737	Example: rotate the image by 90 degrees
738
739	=cut
740
741	sub rotate($$$$$$) {
742	my $img = pop;
743	$img->rotate (
744	$_[0],
745	$_[1],
746	$_[2] * $img->w,
747	$_[3] * $img->h,
748	$_[4] * (3.14159265 / 180),
749	)
750	}
751
752	=back	927	=back
753		928
		929	=head2 OTHER STUFF
		930
		931	Anything that didn't fit any of the other categories, even after applying
		932	force and closing our eyes.
		933
		934	=over 4
		935
		936	=item keep { ... }
		937
		938	This operator takes a code block as argument, that is, one or more
		939	statements enclosed by braces.
		940
		941	The trick is that this code block is only evaluated when the outcome
		942	changes - on other calls the C<keep> simply returns the image it computed
		943	previously (yes, it should only be used with images). Or in other words,
		944	C<keep> I<caches> the result of the code block so it doesn't need to be
		945	computed again.
		946
		947	This can be extremely useful to avoid redoing slow operations - for
		948	example, if your background expression takes the root background, blurs it
		949	and then root-aligns it it would have to blur the root background on every
		950	window move or resize.
		951
		952	Another example is C<load>, which can be quite slow.
		953
		954	In fact, urxvt itself encloses the whole expression in some kind of
		955	C<keep> block so it only is reevaluated as required.
		956
		957	Putting the blur into a C<keep> block will make sure the blur is only done
		958	once, while the C<rootalign> is still done each time the window moves.
		959
		960	rootalign keep { blur 10, root }
		961
		962	This leaves the question of how to force reevaluation of the block,
		963	in case the root background changes: If expression inside the block
		964	is sensitive to some event (root background changes, window geometry
		965	changes), then it will be reevaluated automatically as needed.
		966
		967	=cut
		968
		969	sub keep(&) {
		970	my $id = $_[0]+0;
		971
		972	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		973
		974	unless ($frame->[FR_CACHE]) {
		975	$frame->[FR_CACHE] = [ $_[0]() ];
		976
		977	my $self = $self;
		978	my $frame = $frame;
		979	Scalar::Util::weaken $frame;
		980	$self->compile_frame ($frame, sub {
		981	# clear this frame cache, also for all parents
		982	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		983	undef $frame->[FR_CACHE];
		984	}
		985
		986	$self->recalculate;
		987	});
		988	};
		989
		990	# in scalar context we always return the first original result, which
		991	# is not quite how perl works.
		992	wantarray
		993	? @{ $frame->[FR_CACHE] }
		994	: $frame->[FR_CACHE][0]
		995	}
		996
		997	# sub keep_clear() {
		998	# delete $self->{frame_cache};
		999	# }
		1000
		1001	=back
		1002
754	=cut	1003	=cut
755		1004
756	}	1005	}
757		1006
758	sub parse_expr {	1007	sub parse_expr {
759	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	1008	my $expr = eval
		1009	"sub {\n"
		1010	. "package urxvt::bgdsl;\n"
		1011	. "#line 0 'background expression'\n"
		1012	. "$_[0]\n"
		1013	. "}";
760	die if $@;	1014	die if $@;
761	$expr	1015	$expr
762	}	1016	}
763		1017
764	# compiles a parsed expression	1018	# compiles a parsed expression
765	sub set_expr {	1019	sub set_expr {
766	my ($self, $expr) = @_;	1020	my ($self, $expr) = @_;
767		1021
		1022	$self->{root} = []; # the outermost frame
768	$self->{expr} = $expr;	1023	$self->{expr} = $expr;
769	$self->recalculate;	1024	$self->recalculate;
		1025	}
		1026
		1027	# takes a hash of sensitivity indicators and installs watchers
		1028	sub compile_frame {
		1029	my ($self, $frame, $cb) = @_;
		1030
		1031	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		1032	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		1033
		1034	# don't keep stuff alive
		1035	Scalar::Util::weaken $state;
		1036
		1037	if ($again->{nested}) {
		1038	$state->{nested} = 1;
		1039	} else {
		1040	delete $state->{nested};
		1041	}
		1042
		1043	if (my $interval = $again->{time}) {
		1044	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		1045	if $state->{time}[0] != $interval;
		1046
		1047	# callback might have changed, although we could just rule that out
		1048	$state->{time}[1]->cb (sub {
		1049	++$state->{counter};
		1050	$cb->();
		1051	});
		1052	} else {
		1053	delete $state->{time};
		1054	}
		1055
		1056	if ($again->{position}) {
		1057	$state->{position} = $self->on (position_change => $cb);
		1058	} else {
		1059	delete $state->{position};
		1060	}
		1061
		1062	if ($again->{size}) {
		1063	$state->{size} = $self->on (size_change => $cb);
		1064	} else {
		1065	delete $state->{size};
		1066	}
		1067
		1068	if ($again->{rootpmap}) {
		1069	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		1070	} else {
		1071	delete $state->{rootpmap};
		1072	}
770	}	1073	}
771		1074
772	# evaluate the current bg expression	1075	# evaluate the current bg expression
773	sub recalculate {	1076	sub recalculate {
774	my ($arg_self) = @_;	1077	my ($arg_self) = @_;
…		…
784		1087
785	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1088	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
786		1089
787	# set environment to evaluate user expression	1090	# set environment to evaluate user expression
788		1091
789	local $self = $arg_self;	1092	local $self = $arg_self;
790
791	local $HOME = $ENV{HOME};	1093	local $HOME = $ENV{HOME};
792	local $old = $self->{state};	1094	local $frame = $self->{root};
793	local $new = my $state = $self->{state} = {};
794		1095
795	($x, $y, $w, $h) =
796	$self->background_geometry ($self->{border});	1096	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
797		1097
798	# evaluate user expression	1098	# evaluate user expression
799		1099
800	my $img = eval { $self->{expr}->() };	1100	my @img = eval { $self->{expr}->() };
801	warn $@ if $@;#d#	1101	die $@ if $@;
802	die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";	1102	die "background-expr did not return anything.\n" unless @img;
		1103	die "background-expr: expected image(s), got something else.\n"
		1104	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
803		1105
804	$state->{size_sensitive} = 1	1106	my $img = urxvt::bgdsl::merge @img;
		1107
		1108	$frame->[FR_AGAIN]{size} = 1
805	if $img->repeat_mode != urxvt::RepeatNormal;	1109	if $img->repeat_mode != urxvt::RepeatNormal;
806		1110
807	# if the expression is sensitive to external events, prepare reevaluation then	1111	# if the expression is sensitive to external events, prepare reevaluation then
808		1112	$self->compile_frame ($frame, sub { $arg_self->recalculate });
809	my $repeat;
810
811	if (my $again = $state->{again}) {
812	$repeat = 1;
813	my $self = $self;
814	$state->{timer} = $again == $old->{again}
815	? $old->{timer}
816	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
817	++$self->{counter};
818	$self->recalculate
819	});
820	}
821
822	if (delete $state->{position_sensitive}) {
823	$repeat = 1;
824	$self->enable (position_change => sub { $_[0]->recalculate });
825	} else {
826	$self->disable ("position_change");
827	}
828
829	if (delete $state->{size_sensitive}) {
830	$repeat = 1;
831	$self->enable (size_change => sub { $_[0]->recalculate });
832	} else {
833	$self->disable ("size_change");
834	}
835
836	if (delete $state->{rootpmap_sensitive}) {
837	$repeat = 1;
838	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
839	} else {
840	$self->disable ("rootpmap_change");
841	}
842		1113
843	# clear stuff we no longer need	1114	# clear stuff we no longer need
844		1115
845	%$old = ();	1116	# unless (%{ $frame->[FR_STATE] }) {
846
847	unless ($repeat) {
848	delete $self->{state};	1117	# delete $self->{state};
849	delete $self->{expr};	1118	# delete $self->{expr};
850	}	1119	# }
851		1120
852	# set background pixmap	1121	# set background pixmap
853		1122
854	$self->set_background ($img, $self->{border});	1123	$self->set_background ($img, $self->{border});
855	$self->scr_recolour (0);	1124	$self->scr_recolour (0);

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.49 by root, Sun Jun 10 15:29:18 2012 UTC vs. Revision 1.77 by root, Tue Sep 4 11:21:11 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.49 by root, Sun Jun 10 15:29:18 2012 UTC vs.
Revision 1.77 by root, Tue Sep 4 11:21:11 2012 UTC