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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.46 by root, Sun Jun 10 13:32:55 2012 UTC vs.
Revision 1.75 by root, Fri Aug 10 20:07:11 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
		281	our %_IMG_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);
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 us 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	die "root op not supported, exg, we need you";	349	$self->new_img_from_root
257	}	350	}
258		351
259	=item solid $colour	352	=item solid $colour
260		353
261	=item solid $width, $height, $colour	354	=item solid $width, $height, $colour
…		…
269	=cut	362	=cut
270		363
271	sub solid($;$$) {	364	sub solid($;$$) {
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 $img
…		…
285		378
286	sub clone($) {	379	sub clone($) {
287	$_[0]->clone	380	$_[0]->clone
288	}	381	}
289		382
290	=back	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	}
291		426
292	=head2 TILING MODES	427	=head2 TILING MODES
293		428
294	The following operators modify the tiling mode of an image, that is, the	429	The following operators modify the tiling mode of an image, that is, the
295	way that pixels outside the image area are painted when the image is used.	430	way that pixels outside the image area are painted when the image is used.
…		…
325	become transparent. This mode is most useful when you want to place an	460	become transparent. This mode is most useful when you want to place an
326	image over another image or the background colour while leaving all	461	image over another image or the background colour while leaving all
327	background pixels outside the image unchanged.	462	background pixels outside the image unchanged.
328		463
329	Example: load an image and display it in the upper left corner. The rest	464	Example: load an image and display it in the upper left corner. The rest
330	of the space is left "empty" (transparent or wahtever your compisotr does	465	of the space is left "empty" (transparent or whatever your compositor does
331	in alpha mode, else background colour).	466	in alpha mode, else background colour).
332		467
333	pad load "mybg.png"	468	pad load "mybg.png"
334		469
335	=item extend $img	470	=item extend $img
336		471
337	Extends the image over the whole plane, using the closest pixel in the	472	Extends the image over the whole plane, using the closest pixel in the
338	area outside the image. This mode is mostly useful when you more complex	473	area outside the image. This mode is mostly useful when you use more complex
339	filtering operations and want the pixels outside the image to have the	474	filtering operations and want the pixels outside the image to have the
340	same values as the pixels near the edge.	475	same values as the pixels near the edge.
341		476
342	Example: just for curiosity, how does this pixel extension stuff work?	477	Example: just for curiosity, how does this pixel extension stuff work?
343		478
…		…
392	Using these functions make your expression sensitive to window moves.	527	Using these functions make your expression sensitive to window moves.
393		528
394	These functions are mainly useful to align images to the root window.	529	These functions are mainly useful to align images to the root window.
395		530
396	Example: load an image and align it so it looks as if anchored to the	531	Example: load an image and align it so it looks as if anchored to the
397	background.	532	background (that's exactly what C<rootalign> does btw.):
398		533
399	move -TX, -TY, load "mybg.png"	534	move -TX, -TY, keep { load "mybg.png" }
400		535
401	=item TW	536	=item TW
402		537
403	Return the width (C<TW>) and height (C<TH>) of the terminal window (the	538	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
404	terminal window is the full window by default, and the character area only	539	terminal window is the full window by default, and the character area only
…		…
410	the window size to conserve memory.	545	the window size to conserve memory.
411		546
412	Example: take the screen background, clip it to the window size, blur it a	547	Example: take the screen background, clip it to the window size, blur it a
413	bit, align it to the window position and use it as background.	548	bit, align it to the window position and use it as background.
414		549
415	clip move -TX, -TY, blur 5, root	550	clip move -TX, -TY, keep { blur 5, root }
416		551
417	=cut	552	=cut
418		553
419	sub TX() { $new->{position_sensitive} = 1; $x }	554	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
420	sub TY() { $new->{position_sensitive} = 1; $y }	555	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
421	sub TW() { $new->{size_sensitive} = 1; $w }	556	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
422	sub TH() { $new->{size_sensitive} = 1; $h }	557	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
423		558
424	=item now	559	=item now
425		560
426	Returns the current time as (fractional) seconds since the epoch.	561	Returns the current time as (fractional) seconds since the epoch.
427		562
…		…
434	C<$seconds> seconds.	569	C<$seconds> seconds.
435		570
436	Example: load some image and rotate it according to the time of day (as if it were	571	Example: load some image and rotate it according to the time of day (as if it were
437	the hour pointer of a clock). Update this image every minute.	572	the hour pointer of a clock). Update this image every minute.
438		573
		574	again 60;
439	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"	575	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
440		576
441	=item counter $seconds	577	=item counter $seconds
442		578
443	Like C<again>, but also returns an increasing counter value, starting at	579	Like C<again>, but also returns an increasing counter value, starting at
444	0, which might be useful for some simple animation effects.	580	0, which might be useful for some simple animation effects.
…		…
446	=cut	582	=cut
447		583
448	sub now() { urxvt::NOW }	584	sub now() { urxvt::NOW }
449		585
450	sub again($) {	586	sub again($) {
451	$new->{again} = $_[0];	587	$frame->[FR_AGAIN]{time} = $_[0];
452	}	588	}
453		589
454	sub counter($) {	590	sub counter($) {
455	$new->{again} = $_[0];	591	$frame->[FR_AGAIN]{time} = $_[0];
456	$self->{counter} + 0	592	$frame->[FR_STATE]{counter} + 0
457	}	593	}
458		594
459	=back	595	=back
460		596
461	=head2 SHAPE CHANGING OPERATORS	597	=head2 SHAPE CHANGING OPERATORS
…		…
481	assumed.	617	assumed.
482		618
483	Example: load an image, blur it, and clip it to the window size to save	619	Example: load an image, blur it, and clip it to the window size to save
484	memory.	620	memory.
485		621
486	clip blur 10, load "mybg.png"	622	clip keep { blur 10, load "mybg.png" }
487		623
488	=cut	624	=cut
489		625
490	sub clip($;$$;$$) {	626	sub clip($;$$;$$) {
491	my $img = pop;	627	my $img = pop;
…		…
585	the terminal window (or the box specified by C<$width> and C<$height> if	721	the terminal window (or the box specified by C<$width> and C<$height> if
586	given).	722	given).
587		723
588	Example: load an image and center it.	724	Example: load an image and center it.
589		725
590	center pad load "mybg.png"	726	center keep { pad load "mybg.png" }
591		727
592	=item rootalign $img	728	=item rootalign $img
593		729
594	Moves the image so that it appears glued to the screen as opposed to the	730	Moves the image so that it appears glued to the screen as opposed to the
595	window. This gives the illusion of a larger area behind the window. It is	731	window. This gives the illusion of a larger area behind the window. It is
596	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	732	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
597	top left of the screen.	733	top left of the screen.
598		734
599	Example: load a background image, put it in mirror mode and root align it.	735	Example: load a background image, put it in mirror mode and root align it.
600		736
601	rootalign mirror load "mybg.png"	737	rootalign keep { mirror load "mybg.png" }
602		738
603	Example: take the screen background and align it, giving the illusion of	739	Example: take the screen background and align it, giving the illusion of
604	transparency as long as the window isn't in front of other windows.	740	transparency as long as the window isn't in front of other windows.
605		741
606	rootalign root	742	rootalign root
…		…
631		767
632	sub rootalign($) {	768	sub rootalign($) {
633	move -TX, -TY, $_[0]	769	move -TX, -TY, $_[0]
634	}	770	}
635		771
		772	=item rotate $center_x, $center_y, $degrees, $img
		773
		774	Rotates the image clockwise by C<$degrees> degrees, around the point at
		775	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		776
		777	Example: rotate the image by 90 degrees around it's center.
		778
		779	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		780
		781	=cut
		782
		783	sub rotate($$$$) {
		784	my $img = pop;
		785	$img->rotate (
		786	$_[0] * ($img->w + $img->x),
		787	$_[1] * ($img->h + $img->y),
		788	$_[2] * (3.14159265 / 180),
		789	)
		790	}
		791
636	=back	792	=back
637		793
638	=head2 COLOUR MODIFICATIONS	794	=head2 COLOUR MODIFICATIONS
639		795
640	The following operators change the pixels of the image.	796	The following operators change the pixels of the image.
641		797
642	=over 4	798	=over 4
		799
		800	=item tint $color, $img
		801
		802	Tints the image in the given colour.
		803
		804	Example: tint the image red.
		805
		806	tint "red", load "rgb.png"
		807
		808	Example: the same, but specify the colour by component.
		809
		810	tint [1, 0, 0], load "rgb.png"
		811
		812	=cut
		813
		814	sub tint($$) {
		815	$_[1]->tint ($_[0])
		816	}
643		817
644	=item contrast $factor, $img	818	=item contrast $factor, $img
645		819
646	=item contrast $r, $g, $b, $img	820	=item contrast $r, $g, $b, $img
647		821
…		…
674		848
675	Values less than 0 reduce brightness, while values larger than 0 increase	849	Values less than 0 reduce brightness, while values larger than 0 increase
676	it. Useful range is from -1 to 1 - the former results in a black, the	850	it. Useful range is from -1 to 1 - the former results in a black, the
677	latter in a white picture.	851	latter in a white picture.
678		852
679	Due to idiosynchrasies in the underlying XRender extension, biases less	853	Due to idiosyncrasies in the underlying XRender extension, biases less
680	than zero can be I<very> slow.	854	than zero can be I<very> slow.
		855
		856	You can also try the experimental(!) C<muladd> operator.
681		857
682	=cut	858	=cut
683		859
684	sub contrast($$;$$;$) {	860	sub contrast($$;$$;$) {
685	my $img = pop;	861	my $img = pop;
686	my ($r, $g, $b, $a) = @_;	862	my ($r, $g, $b, $a) = @_;
687		863
688	($g, $b) = ($r, $r) if @_ < 4;	864	($g, $b) = ($r, $r) if @_ < 3;
689	$a = 1 if @_ < 5;	865	$a = 1 if @_ < 4;
690		866
691	$img = $img->clone;	867	$img = $img->clone;
692	$img->contrast ($r, $g, $b, $a);	868	$img->contrast ($r, $g, $b, $a);
693	$img	869	$img
694	}	870	}
695		871
696	sub brightness($$;$$;$) {	872	sub brightness($$;$$;$) {
697	my $img = pop;	873	my $img = pop;
698	my ($r, $g, $b, $a) = @_;	874	my ($r, $g, $b, $a) = @_;
699		875
700	($g, $b) = ($r, $r) if @_ < 4;	876	($g, $b) = ($r, $r) if @_ < 3;
701	$a = 1 if @_ < 5;	877	$a = 1 if @_ < 4;
702		878
703	$img = $img->clone;	879	$img = $img->clone;
704	$img->brightness ($r, $g, $b, $a);	880	$img->brightness ($r, $g, $b, $a);
705	$img	881	$img
		882	}
		883
		884	=item muladd $mul, $add, $img # EXPERIMENTAL
		885
		886	First multipliesthe pixels by C<$mul>, then adds C<$add>. This cna be used
		887	to implement brightness and contrast at the same time, with a wider value
		888	range than contrast and brightness operators.
		889
		890	Due to numerous bugs in XRender implementations, it can also introduce a
		891	number of visual artifacts.
		892
		893	Example: increase contrast by a factor of C<$c> without changing image
		894	brightness too much.
		895
		896	muladd $c, (1 - $c) * 0.5, $img
		897
		898	=cut
		899
		900	sub muladd($$$) {
		901	$_[2]->muladd ($_[0], $_[1])
706	}	902	}
707		903
708	=item blur $radius, $img	904	=item blur $radius, $img
709		905
710	=item blur $radius_horz, $radius_vert, $img	906	=item blur $radius_horz, $radius_vert, $img
…		…
722	sub blur($$;$) {	918	sub blur($$;$) {
723	my $img = pop;	919	my $img = pop;
724	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	920	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
725	}	921	}
726		922
727	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
728
729	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
730	pointer at C<$center_x> and C<$center_y> (specified as factor of image
731	width/height), generating a new image with width C<$new_width> and height
732	C<$new_height>.
733
734	#TODO# new width, height, maybe more operators?
735
736	Example: rotate the image by 90 degrees
737
738	=cut
739
740	sub rotate($$$$$$) {
741	my $img = pop;
742	$img->rotate (
743	$_[0],
744	$_[1],
745	$_[2] * $img->w,
746	$_[3] * $img->h,
747	$_[4] * (3.14159265 / 180),
748	)
749	}
750
751	=back	923	=back
752		924
		925	=head2 OTHER STUFF
		926
		927	Anything that didn't fit any of the other categories, even after applying
		928	force and closing our eyes.
		929
		930	=over 4
		931
		932	=item keep { ... }
		933
		934	This operator takes a code block as argument, that is, one or more
		935	statements enclosed by braces.
		936
		937	The trick is that this code block is only evaluated when the outcome
		938	changes - on other calls the C<keep> simply returns the image it computed
		939	previously (yes, it should only be used with images). Or in other words,
		940	C<keep> I<caches> the result of the code block so it doesn't need to be
		941	computed again.
		942
		943	This can be extremely useful to avoid redoing slow operations - for
		944	example, if your background expression takes the root background, blurs it
		945	and then root-aligns it it would have to blur the root background on every
		946	window move or resize.
		947
		948	Another example is C<load>, which can be quite slow.
		949
		950	In fact, urxvt itself encloses the whole expression in some kind of
		951	C<keep> block so it only is reevaluated as required.
		952
		953	Putting the blur into a C<keep> block will make sure the blur is only done
		954	once, while the C<rootalign> is still done each time the window moves.
		955
		956	rootalign keep { blur 10, root }
		957
		958	This leaves the question of how to force reevaluation of the block,
		959	in case the root background changes: If expression inside the block
		960	is sensitive to some event (root background changes, window geometry
		961	changes), then it will be reevaluated automatically as needed.
		962
		963	=cut
		964
		965	sub keep(&) {
		966	my $id = $_[0]+0;
		967
		968	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		969
		970	unless ($frame->[FR_CACHE]) {
		971	$frame->[FR_CACHE] = [ $_[0]() ];
		972
		973	my $self = $self;
		974	my $frame = $frame;
		975	Scalar::Util::weaken $frame;
		976	$self->compile_frame ($frame, sub {
		977	# clear this frame cache, also for all parents
		978	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		979	undef $frame->[FR_CACHE];
		980	}
		981
		982	$self->recalculate;
		983	});
		984	};
		985
		986	# in scalar context we always return the first original result, which
		987	# is not quite how perl works.
		988	wantarray
		989	? @{ $frame->[FR_CACHE] }
		990	: $frame->[FR_CACHE][0]
		991	}
		992
		993	# sub keep_clear() {
		994	# delete $self->{frame_cache};
		995	# }
		996
		997	=back
		998
753	=cut	999	=cut
754		1000
755	}	1001	}
756		1002
757	sub parse_expr {	1003	sub parse_expr {
758	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	1004	my $expr = eval
		1005	"sub {\n"
		1006	. "package urxvt::bgdsl;\n"
		1007	. "#line 0 'background expression'\n"
		1008	. "$_[0]\n"
		1009	. "}";
759	die if $@;	1010	die if $@;
760	$expr	1011	$expr
761	}	1012	}
762		1013
763	# compiles a parsed expression	1014	# compiles a parsed expression
764	sub set_expr {	1015	sub set_expr {
765	my ($self, $expr) = @_;	1016	my ($self, $expr) = @_;
766		1017
		1018	$self->{root} = []; # the outermost frame
767	$self->{expr} = $expr;	1019	$self->{expr} = $expr;
768	$self->recalculate;	1020	$self->recalculate;
		1021	}
		1022
		1023	# takes a hash of sensitivity indicators and installs watchers
		1024	sub compile_frame {
		1025	my ($self, $frame, $cb) = @_;
		1026
		1027	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		1028	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		1029
		1030	# don't keep stuff alive
		1031	Scalar::Util::weaken $state;
		1032
		1033	if ($again->{nested}) {
		1034	$state->{nested} = 1;
		1035	} else {
		1036	delete $state->{nested};
		1037	}
		1038
		1039	if (my $interval = $again->{time}) {
		1040	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		1041	if $state->{time}[0] != $interval;
		1042
		1043	# callback might have changed, although we could just rule that out
		1044	$state->{time}[1]->cb (sub {
		1045	++$state->{counter};
		1046	$cb->();
		1047	});
		1048	} else {
		1049	delete $state->{time};
		1050	}
		1051
		1052	if ($again->{position}) {
		1053	$state->{position} = $self->on (position_change => $cb);
		1054	} else {
		1055	delete $state->{position};
		1056	}
		1057
		1058	if ($again->{size}) {
		1059	$state->{size} = $self->on (size_change => $cb);
		1060	} else {
		1061	delete $state->{size};
		1062	}
		1063
		1064	if ($again->{rootpmap}) {
		1065	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		1066	} else {
		1067	delete $state->{rootpmap};
		1068	}
769	}	1069	}
770		1070
771	# evaluate the current bg expression	1071	# evaluate the current bg expression
772	sub recalculate {	1072	sub recalculate {
773	my ($arg_self) = @_;	1073	my ($arg_self) = @_;
…		…
783		1083
784	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1084	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
785		1085
786	# set environment to evaluate user expression	1086	# set environment to evaluate user expression
787		1087
788	local $self = $arg_self;	1088	local $self = $arg_self;
789
790	local $HOME = $ENV{HOME};	1089	local $HOME = $ENV{HOME};
791	local $old = $self->{state};	1090	local $frame = $self->{root};
792	local $new = my $state = $self->{state} = {};
793		1091
794	($x, $y, $w, $h) =
795	$self->background_geometry ($self->{border});	1092	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
796		1093
797	# evaluate user expression	1094	# evaluate user expression
798		1095
799	my $img = eval { $self->{expr}->() };	1096	my @img = eval { $self->{expr}->() };
800	warn $@ if $@;#d#	1097	die $@ if $@;
		1098	die "background-expr did not return anything.\n" unless @img;
		1099	die "background-expr: expected image(s), got something else.\n"
801	die if !UNIVERSAL::isa $img, "urxvt::img";	1100	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
802		1101
803	$state->{size_sensitive} = 1	1102	my $img = urxvt::bgdsl::merge @img;
		1103
		1104	$frame->[FR_AGAIN]{size} = 1
804	if $img->repeat_mode != urxvt::RepeatNormal;	1105	if $img->repeat_mode != urxvt::RepeatNormal;
805		1106
806	# if the expression is sensitive to external events, prepare reevaluation then	1107	# if the expression is sensitive to external events, prepare reevaluation then
807		1108	$self->compile_frame ($frame, sub { $arg_self->recalculate });
808	my $repeat;
809
810	if (my $again = $state->{again}) {
811	$repeat = 1;
812	my $self = $self;
813	$state->{timer} = $again == $old->{again}
814	? $old->{timer}
815	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
816	++$self->{counter};
817	$self->recalculate
818	});
819	}
820
821	if (delete $state->{position_sensitive}) {
822	$repeat = 1;
823	$self->enable (position_change => sub { $_[0]->recalculate });
824	} else {
825	$self->disable ("position_change");
826	}
827
828	if (delete $state->{size_sensitive}) {
829	$repeat = 1;
830	$self->enable (size_change => sub { $_[0]->recalculate });
831	} else {
832	$self->disable ("size_change");
833	}
834
835	if (delete $state->{rootpmap_sensitive}) {
836	$repeat = 1;
837	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
838	} else {
839	$self->disable ("rootpmap_change");
840	}
841		1109
842	# clear stuff we no longer need	1110	# clear stuff we no longer need
843		1111
844	%$old = ();	1112	# unless (%{ $frame->[FR_STATE] }) {
845
846	unless ($repeat) {
847	delete $self->{state};	1113	# delete $self->{state};
848	delete $self->{expr};	1114	# delete $self->{expr};
849	}	1115	# }
850		1116
851	# set background pixmap	1117	# set background pixmap
852		1118
853	$self->set_background ($img, $self->{border});	1119	$self->set_background ($img, $self->{border});
854	$self->scr_recolour (0);	1120	$self->scr_recolour (0);
…		…
856	}	1122	}
857		1123
858	sub on_start {	1124	sub on_start {
859	my ($self) = @_;	1125	my ($self) = @_;
860		1126
861	my $expr = $self->x_resource ("background.expr")	1127	my $expr = $self->x_resource ("%.expr")
862	or return;	1128	or return;
863		1129
		1130	$self->has_render
		1131	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1132
864	$self->set_expr (parse_expr $expr);	1133	$self->set_expr (parse_expr $expr);
865	$self->{border} = $self->x_resource_boolean ("background.border");	1134	$self->{border} = $self->x_resource_boolean ("%.border");
866		1135
867	$MIN_INTERVAL = $self->x_resource ("background.interval");	1136	$MIN_INTERVAL = $self->x_resource ("%.interval");
868		1137
869	()	1138	()
870	}	1139	}
871		1140

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.46 by root, Sun Jun 10 13:32:55 2012 UTC vs. Revision 1.75 by root, Fri Aug 10 20:07:11 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.46 by root, Sun Jun 10 13:32:55 2012 UTC vs.
Revision 1.75 by root, Fri Aug 10 20:07:11 2012 UTC