[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 1.69 by root, Mon Jul 2 01:32:26 2012 UTC

…		…
26	to be as simple as possible.	26	to be as simple as possible.
27		27
28	For example, to load an image and scale it to the window size, you would	28	For example, to load an image and scale it to the window size, you would
29	use:	29	use:
30		30
31	urxvt --background-expr 'scale load "/path/to/mybg.png"'	31	urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
32		32
33	Or specified as a X resource:	33	Or specified as a X resource:
34		34
35	URxvt.background-expr: scale load "/path/to/mybg.png"	35	URxvt.background-expr: scale keep { load "/path/to/mybg.png" }
36		36
37	=head1 THEORY OF OPERATION	37	=head1 THEORY OF OPERATION
38		38
39	At startup, just before the window is mapped for the first time, the	39	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	40	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	53	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	54	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	55	pixmap is replaced by another one the root background changes; or when the
56	timer elapses), then the expression will be evaluated again.	56	timer elapses), then the expression will be evaluated again.
57		57
58	For example, an expression such as C<scale load "$HOME/mybg.png"> scales the	58	For example, an expression such as C<scale keep { load "$HOME/mybg.png"
59	image to the window size, so it relies on the window size and will	59	}> 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	60	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	61	example. That ensures that the picture always fills the terminal, even
62	after its size changes.	62	after its size changes.
63		63
64	=head2 EXPRESSIONS	64	=head2 EXPRESSIONS
65		65
66	Expressions are normal Perl expressions, in fact, they are Perl blocks -	66	Expressions are normal Perl expressions, in fact, they are Perl blocks -
67	which means you could use multiple lines and statements:	67	which means you could use multiple lines and statements:
68		68
		69	scale keep {
69	again 3600;	70	again 3600;
70	if (localtime now)[6]) {	71	if (localtime now)[6]) {
71	return scale load "$HOME/weekday.png";	72	return load "$HOME/weekday.png";
72	} else {	73	} else {
73	return scale load "$HOME/sunday.png";	74	return load "$HOME/sunday.png";
		75	}
74	}	76	}
75		77
76	This expression gets evaluated once per hour. It will set F<sunday.png> as	78	This inner expression is evaluated once per hour (and whenever the
		79	temrinal window is resized). It sets F<sunday.png> as background on
77	background on Sundays, and F<weekday.png> on all other days.	80	Sundays, and F<weekday.png> on all other days.
78		81
79	Fortunately, we expect that most expressions will be much simpler, with	82	Fortunately, we expect that most expressions will be much simpler, with
80	little Perl knowledge needed.	83	little Perl knowledge needed.
81		84
82	Basically, you always start with a function that "generates" an image	85	Basically, you always start with a function that "generates" an image
…		…
115	horizontal and vertical dimensions. For example, this halves the image	118	horizontal and vertical dimensions. For example, this halves the image
116	width and doubles the image height:	119	width and doubles the image height:
117		120
118	scale 0.5, 2, load "$HOME/mypic.png"	121	scale 0.5, 2, load "$HOME/mypic.png"
119		122
120	Other effects than scaling are also readily available, for example, you can	123	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:	124	because each time the terminal is resized, it loads the PNG image agin
		125	and scales it. Scaling is usually fast (and unavoidable), but loading the
		126	image can be quite time consuming. This is where C<keep> comes in handy:
122		127
		128	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		129
		130	The C<keep> operator executes all the statements inside the braces only
		131	once, or when it thinks the outcome might change. In other cases it
		132	returns the last value computed by the brace block.
		133
		134	This means that the C<load> is only executed once, which makes it much
		135	faster, but also means that more memory is being used, because the loaded
		136	image must be kept in memory at all times. In this expression, the
		137	trade-off is likely worth it.
		138
		139	But back to effects: Other effects than scaling are also readily
		140	available, for example, you can tile the image to fill the whole window,
		141	instead of resizing it:
		142
123	tile load "$HOME/mypic.png"	143	tile keep { load "$HOME/mypic.png" }
124		144
125	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator	145	In fact, images returned by C<load> are in C<tile> mode by default, so the
126	is kind of superfluous.	146	C<tile> operator is kind of superfluous.
127		147
128	Another common effect is to mirror the image, so that the same edges touch:	148	Another common effect is to mirror the image, so that the same edges
		149	touch:
129		150
130	mirror load "$HOME/mypic.png"	151	mirror keep { load "$HOME/mypic.png" }
131		152
132	This is also a typical background expression:	153	Another common background expression is:
133		154
134	rootalign root	155	rootalign root
135		156
136	It first takes a snapshot of the screen background image, and then	157	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	158	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	159	left corner of the terminal window)- the result is pseudo-transparency:
139	moved around.	160	the image seems to be static while the window is moved around.
140		161
141	=head2 CYCLES AND CACHING	162	=head2 CACHING AND SENSITIVITY
142		163
143	As has been mentioned before, the expression might be evaluated multiple	164	Since some operations (such as C<load> and C<blur>) can take a long time,
144	times. Each time the expression is reevaluated, a new cycle is said to	165	caching results can be very important for a smooth operation. Caching can
145	have begun. Many operators cache their results till the next cycle.	166	also be useful to reduce memory usage, though, for example, when an image
		167	is cached by C<load>, it could be shared by multiple terminal windows
		168	running inside urxvtd.
146		169
147	For example, the C<load> operator keeps a copy of the image. If it is	170	=head3 C<keep { ... }> caching
148	asked to load the same image on the next cycle it will not load it again,
149	but return the cached copy.
150		171
151	This only works for one cycle though, so as long as you load the same	172	The most important way to cache expensive operations is to use C<keep {
152	image every time, it will always be cached, but when you load a different	173	... }>. The C<keep> operator takes a block of multiple statements enclosed
153	image, it will forget about the first one.	174	by C<{}> and keeps the return value in memory.
154		175
155	This allows you to either speed things up by keeping multiple images in	176	An expression can be "sensitive" to various external events, such as
156	memory, or conserve memory by loading images more often.	177	scaling or moving the window, root background changes and timers. Simply
		178	using an expression (such as C<scale> without parameters) that depends on
		179	certain changing values (called "variables"), or using those variables
		180	directly, will make an expression sensitive to these events - for example,
		181	using C<scale> or C<TW> will make the expression sensitive to the terminal
		182	size, and thus to resizing events.
157		183
158	For example, you can keep two images in memory and use a random one like	184	When such an event happens, C<keep> will automatically trigger a
159	this:	185	reevaluation of the whole expression with the new value of the expression.
160		186
161	my $img1 = load "img1.png";	187	C<keep> is most useful for expensive operations, such as C<blur>:
162	my $img2 = load "img2.png";
163	(0.5 > rand) ? $img1 : $img2
164		188
165	Since both images are "loaded" every time the expression is evaluated,	189	rootalign keep { blur 20, root }
166	they are always kept in memory. Contrast this version:
167		190
168	my $path1 = "img1.png";	191	This makes a blurred copy of the root background once, and on subsequent
169	my $path2 = "img2.png";	192	calls, just root-aligns it. Since C<blur> is usually quite slow and
170	load ((0.5 > rand) ? $path1 : $path2)	193	C<rootalign> is quite fast, this trades extra memory (for the cached
		194	blurred pixmap) with speed (blur only needs to be redone when root
		195	changes).
171		196
172	Here, a path is selected randomly, and load is only called for one image,	197	=head3 C<load> caching
173	so keeps only one image in memory. If, on the next evaluation, luck	198
174	decides to use the other path, then it will have to load that image again.	199	The C<load> operator itself does not keep images in memory, but as long as
		200	the image is still in memory, C<load> will use the in-memory image instead
		201	of loading it freshly from disk.
		202
		203	That means that this expression:
		204
		205	keep { load "$HOME/path..." }
		206
		207	Not only caches the image in memory, other terminal instances that try to
		208	C<load> it can reuse that in-memory copy.
175		209
176	=head1 REFERENCE	210	=head1 REFERENCE
177		211
178	=head2 COMMAND LINE SWITCHES	212	=head2 COMMAND LINE SWITCHES
179		213
…		…
203	=back	237	=back
204		238
205	=cut	239	=cut
206		240
207	our %_IMG_CACHE;	241	our %_IMG_CACHE;
208	our %_ONCE_CACHE;
209	our $HOME;	242	our $HOME;
210	our ($self, $old, $new);	243	our ($self, $frame);
211	our ($x, $y, $w, $h);	244	our ($x, $y, $w, $h);
212		245
213	# enforce at least this interval between updates	246	# enforce at least this interval between updates
214	our $MIN_INTERVAL = 6/59.951;	247	our $MIN_INTERVAL = 6/59.951;
215		248
216	{	249	{
217	package urxvt::bgdsl; # background language	250	package urxvt::bgdsl; # background language
		251
		252	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
		253	sub FR_CACHE () { 1 } # cached values
		254	sub FR_AGAIN () { 2 } # what this expr is sensitive to
		255	sub FR_STATE () { 3 } # watchers etc.
218		256
219	use List::Util qw(min max sum shuffle);	257	use List::Util qw(min max sum shuffle);
220		258
221	=head2 PROVIDERS/GENERATORS	259	=head2 PROVIDERS/GENERATORS
222		260
…		…
229	=item load $path	267	=item load $path
230		268
231	Loads the image at the given C<$path>. The image is set to plane tiling	269	Loads the image at the given C<$path>. The image is set to plane tiling
232	mode.	270	mode.
233		271
234	Loaded images will be cached for one cycle.	272	If the image is already in memory (e.g. because another terminal instance
		273	uses it), then the in-memory copy us returned instead.
		274
		275	=item load_uc $path
		276
		277	Load uncached - same as load, but does not cache the image, which means it
		278	is I<always> loaded from the filesystem again.
235		279
236	=cut	280	=cut
237		281
238	sub load($) {	282	sub load($) {
239	my ($path) = @_;	283	my ($path) = @_;
240		284
241	$new->{load}{$path} = $old->{load}{$path} \|\| $self->new_img_from_file ($path);	285	$_IMG_CACHE{$path} \|\| do {
		286	my $img = $self->new_img_from_file ($path);
		287	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		288	$img
		289	}
242	}	290	}
243		291
244	=item root	292	=item root
245		293
246	Returns the root window pixmap, that is, hopefully, the background image	294	Returns the root window pixmap, that is, hopefully, the background image
247	of your screen. The image is set to extend mode.	295	of your screen.
248		296
249	This function makes your expression root sensitive, that means it will be	297	This function makes your expression root sensitive, that means it will be
250	reevaluated when the bg image changes.	298	reevaluated when the bg image changes.
251		299
252	=cut	300	=cut
253		301
254	sub root() {	302	sub root() {
255	$new->{rootpmap_sensitive} = 1;	303	$frame->[FR_AGAIN]{rootpmap} = 1;
256	$self->new_img_from_root	304	$self->new_img_from_root
257	}	305	}
258		306
259	=item solid $colour	307	=item solid $colour
260		308
…		…
269	=cut	317	=cut
270		318
271	sub solid($;$$) {	319	sub solid($;$$) {
272	my $colour = pop;	320	my $colour = pop;
273		321
274	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	322	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
275	$img->fill ($colour);	323	$img->fill ($colour);
276	$img	324	$img
277	}	325	}
278		326
279	=item clone $img	327	=item clone $img
…		…
283		331
284	=cut	332	=cut
285		333
286	sub clone($) {	334	sub clone($) {
287	$_[0]->clone	335	$_[0]->clone
		336	}
		337
		338	=item merge $img ...
		339
		340	Takes any number of images and merges them together, creating a single
		341	image containing them all. The tiling mode of the first image is used as
		342	the tiling mode of the resulting image.
		343
		344	This function is called automatically when an expression returns multiple
		345	images.
		346
		347	=cut
		348
		349	sub merge(@) {
		350	return $_[0] unless $#_;
		351
		352	# rather annoyingly clumsy, but optimisation is for another time
		353
		354	my $x0 = +1e9;
		355	my $y0 = +1e9;
		356	my $x1 = -1e9;
		357	my $y1 = -1e9;
		358
		359	for (@_) {
		360	my ($x, $y, $w, $h) = $_->geometry;
		361
		362	$x0 = $x if $x0 > $x;
		363	$y0 = $y if $y0 > $y;
		364
		365	$x += $w;
		366	$y += $h;
		367
		368	$x1 = $x if $x1 < $x;
		369	$y1 = $y if $y1 < $y;
		370	}
		371
		372	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		373	$base->repeat_mode ($_[0]->repeat_mode);
		374	$base->fill ([0, 0, 0, 0]);
		375
		376	$base->draw ($_)
		377	for @_;
		378
		379	$base
288	}	380	}
289		381
290	=head2 TILING MODES	382	=head2 TILING MODES
291		383
292	The following operators modify the tiling mode of an image, that is, the	384	The following operators modify the tiling mode of an image, that is, the
…		…
390	Using these functions make your expression sensitive to window moves.	482	Using these functions make your expression sensitive to window moves.
391		483
392	These functions are mainly useful to align images to the root window.	484	These functions are mainly useful to align images to the root window.
393		485
394	Example: load an image and align it so it looks as if anchored to the	486	Example: load an image and align it so it looks as if anchored to the
395	background.	487	background (that's exactly what C<rootalign> does btw.):
396		488
397	move -TX, -TY, load "mybg.png"	489	move -TX, -TY, keep { load "mybg.png" }
398		490
399	=item TW	491	=item TW
400		492
401	Return the width (C<TW>) and height (C<TH>) of the terminal window (the	493	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	494	terminal window is the full window by default, and the character area only
…		…
408	the window size to conserve memory.	500	the window size to conserve memory.
409		501
410	Example: take the screen background, clip it to the window size, blur it a	502	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.	503	bit, align it to the window position and use it as background.
412		504
413	clip move -TX, -TY, blur 5, root	505	clip move -TX, -TY, keep { blur 5, root }
414		506
415	=cut	507	=cut
416		508
417	sub TX() { $new->{position_sensitive} = 1; $x }	509	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
418	sub TY() { $new->{position_sensitive} = 1; $y }	510	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
419	sub TW() { $new->{size_sensitive} = 1; $w }	511	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
420	sub TH() { $new->{size_sensitive} = 1; $h }	512	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
421		513
422	=item now	514	=item now
423		515
424	Returns the current time as (fractional) seconds since the epoch.	516	Returns the current time as (fractional) seconds since the epoch.
425		517
…		…
432	C<$seconds> seconds.	524	C<$seconds> seconds.
433		525
434	Example: load some image and rotate it according to the time of day (as if it were	526	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.	527	the hour pointer of a clock). Update this image every minute.
436		528
		529	again 60;
437	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"	530	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
438		531
439	=item counter $seconds	532	=item counter $seconds
440		533
441	Like C<again>, but also returns an increasing counter value, starting at	534	Like C<again>, but also returns an increasing counter value, starting at
442	0, which might be useful for some simple animation effects.	535	0, which might be useful for some simple animation effects.
…		…
444	=cut	537	=cut
445		538
446	sub now() { urxvt::NOW }	539	sub now() { urxvt::NOW }
447		540
448	sub again($) {	541	sub again($) {
449	$new->{again} = $_[0];	542	$frame->[FR_AGAIN]{time} = $_[0];
450	}	543	}
451		544
452	sub counter($) {	545	sub counter($) {
453	$new->{again} = $_[0];	546	$frame->[FR_AGAIN]{time} = $_[0];
454	$self->{counter} + 0	547	$frame->[FR_STATE]{counter} + 0
455	}	548	}
456		549
457	=back	550	=back
458		551
459	=head2 SHAPE CHANGING OPERATORS	552	=head2 SHAPE CHANGING OPERATORS
…		…
479	assumed.	572	assumed.
480		573
481	Example: load an image, blur it, and clip it to the window size to save	574	Example: load an image, blur it, and clip it to the window size to save
482	memory.	575	memory.
483		576
484	clip blur 10, load "mybg.png"	577	clip keep { blur 10, load "mybg.png" }
485		578
486	=cut	579	=cut
487		580
488	sub clip($;$$;$$) {	581	sub clip($;$$;$$) {
489	my $img = pop;	582	my $img = pop;
…		…
583	the terminal window (or the box specified by C<$width> and C<$height> if	676	the terminal window (or the box specified by C<$width> and C<$height> if
584	given).	677	given).
585		678
586	Example: load an image and center it.	679	Example: load an image and center it.
587		680
588	center pad load "mybg.png"	681	center keep { pad load "mybg.png" }
589		682
590	=item rootalign $img	683	=item rootalign $img
591		684
592	Moves the image so that it appears glued to the screen as opposed to the	685	Moves the image so that it appears glued to the screen as opposed to the
593	window. This gives the illusion of a larger area behind the window. It is	686	window. This gives the illusion of a larger area behind the window. It is
594	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	687	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
595	top left of the screen.	688	top left of the screen.
596		689
597	Example: load a background image, put it in mirror mode and root align it.	690	Example: load a background image, put it in mirror mode and root align it.
598		691
599	rootalign mirror load "mybg.png"	692	rootalign keep { mirror load "mybg.png" }
600		693
601	Example: take the screen background and align it, giving the illusion of	694	Example: take the screen background and align it, giving the illusion of
602	transparency as long as the window isn't in front of other windows.	695	transparency as long as the window isn't in front of other windows.
603		696
604	rootalign root	697	rootalign root
…		…
629		722
630	sub rootalign($) {	723	sub rootalign($) {
631	move -TX, -TY, $_[0]	724	move -TX, -TY, $_[0]
632	}	725	}
633		726
634	=item rotate $center_x, $center_y, $degrees, $new_width, $new_height	727	=item rotate $center_x, $center_y, $degrees, $img
635		728
636	Rotates the image by C<$degrees> degrees, counter-clockwise, around the	729	Rotates the image clockwise by C<$degrees> degrees, around the point at
637	pointer at C<$center_x> and C<$center_y> (specified as factor of image	730	C<$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<$new_height>.
640		731
641	#TODO# new width, height, maybe more operators?
642
643	Example: rotate the image by 90 degrees	732	Example: rotate the image by 90 degrees around it's center.
644		733
645	=cut	734	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
646		735
		736	=cut
		737
647	sub rotate($$$$$$) {	738	sub rotate($$$$) {
648	my $img = pop;	739	my $img = pop;
649	$img->rotate (	740	$img->rotate (
650	$_[0] * $img->w,	741	$_[0] * ($img->w + $img->x),
651	$_[1] * $img->h,	742	$_[1] * ($img->h + $img->y),
652	$_[2] * (3.14159265 / 180),	743	$_[2] * (3.14159265 / 180),
653	$_[3],
654	$_[4],
655	)	744	)
656	}	745	}
657		746
658	=back	747	=back
659		748
…		…
748		837
749	=back	838	=back
750		839
751	=head2 OTHER STUFF	840	=head2 OTHER STUFF
752		841
753	Anything that didn't fit any of the other categories, even after appliyng	842	Anything that didn't fit any of the other categories, even after applying
754	force and closing our eyes.	843	force and closing our eyes.
755		844
756	=over 4	845	=over 4
757		846
758	=item once { ... }	847	=item keep { ... }
759		848
760	This function takes a code block as argument, that is, one or more	849	This operator takes a code block as argument, that is, one or more
761	statements enclosed by braces.	850	statements enclosed by braces.
762		851
763	The trick is that this code block is only evaluated once - future calls	852	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	853	changes - on other calls the C<keep> simply returns the image it computed
765	images).	854	previously (yes, it should only be used with images). Or in other words,
		855	C<keep> I<caches> the result of the code block so it doesn't need to be
		856	computed again.
766		857
767	This can be extremely useful to avoid redoign the same slow operations	858	This can be extremely useful to avoid redoing slow operations - for
768	again and again- for example, if your background expression takes the root	859	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	860	and then root-aligns it it would have to blur the root background on every
770	root background on every window move or resize.	861	window move or resize.
771		862
		863	Another example is C<load>, which can be quite slow.
		864
		865	In fact, urxvt itself encloses the whole expression in some kind of
		866	C<keep> block so it only is reevaluated as required.
		867
772	Putting the blur into a C<once> block will make sure the blur is only done	868	Putting the blur into a C<keep> block will make sure the blur is only done
773	once:	869	once, while the C<rootalign> is still done each time the window moves.
774		870
775	rootlign once { blur 10, root }	871	rootlign keep { blur 10, root }
776		872
777	This leaves the question of how to force reevaluation of the block, in	873	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	874	in case the root background changes: If expression inside the block
779	they ahve been executed before each time the root background changes (if	875	is sensitive to some event (root background changes, window geometry
780	the expression is sensitive to that) or when C<once_again> is called.	876	changes), then it will be reevaluated automatically as needed.
781		877
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	878	=cut
788		879
789	sub once(&) {	880	sub keep(&) {
790	$_ONCE_CACHE{$_[0]+0} \|\|= $_[0]()	881	my $id = $_[0]+0;
		882
		883	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		884
		885	unless ($frame->[FR_CACHE]) {
		886	$frame->[FR_CACHE] = [ $_[0]() ];
		887
		888	my $self = $self;
		889	my $frame = $frame;
		890	Scalar::Util::weaken $frame;
		891	$self->compile_frame ($frame, sub {
		892	# clear this frame cache, also for all parents
		893	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		894	undef $frame->[FR_CACHE];
		895	}
		896
		897	$self->recalculate;
		898	});
		899	};
		900
		901	# in scalar context we always return the first original result, which
		902	# is not quite how perl works.
		903	wantarray
		904	? @{ $frame->[FR_CACHE] }
		905	: $frame->[FR_CACHE][0]
		906	}
		907
		908	# sub keep_clear() {
		909	# delete $self->{frame_cache};
791	}	910	# }
792
793	sub once_again() {
794	%_ONCE_CACHE = ();
795	}
796		911
797	=back	912	=back
798		913
799	=cut	914	=cut
800		915
801	}	916	}
802		917
803	sub parse_expr {	918	sub parse_expr {
804	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	919	my $expr = eval
		920	"sub {\n"
		921	. "package urxvt::bgdsl;\n"
		922	. "#line 0 'background expression'\n"
		923	. "$_[0]\n"
		924	. "}";
805	die if $@;	925	die if $@;
806	$expr	926	$expr
807	}	927	}
808		928
809	# compiles a parsed expression	929	# compiles a parsed expression
810	sub set_expr {	930	sub set_expr {
811	my ($self, $expr) = @_;	931	my ($self, $expr) = @_;
812		932
		933	$self->{root} = [];
813	$self->{expr} = $expr;	934	$self->{expr} = $expr;
814	$self->recalculate;	935	$self->recalculate;
		936	}
		937
		938	# takes a hash of sensitivity indicators and installs watchers
		939	sub compile_frame {
		940	my ($self, $frame, $cb) = @_;
		941
		942	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		943	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		944
		945	# don't keep stuff alive
		946	Scalar::Util::weaken $state;
		947
		948	if ($again->{nested}) {
		949	$state->{nested} = 1;
		950	} else {
		951	delete $state->{nested};
		952	}
		953
		954	if (my $interval = $again->{time}) {
		955	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		956	if $state->{time}[0] != $interval;
		957
		958	# callback might have changed, although we could just rule that out
		959	$state->{time}[1]->cb (sub {
		960	++$state->{counter};
		961	$cb->();
		962	});
		963	} else {
		964	delete $state->{time};
		965	}
		966
		967	if ($again->{position}) {
		968	$state->{position} = $self->on (position_change => $cb);
		969	} else {
		970	delete $state->{position};
		971	}
		972
		973	if ($again->{size}) {
		974	$state->{size} = $self->on (size_change => $cb);
		975	} else {
		976	delete $state->{size};
		977	}
		978
		979	if ($again->{rootpmap}) {
		980	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		981	} else {
		982	delete $state->{rootpmap};
		983	}
815	}	984	}
816		985
817	# evaluate the current bg expression	986	# evaluate the current bg expression
818	sub recalculate {	987	sub recalculate {
819	my ($arg_self) = @_;	988	my ($arg_self) = @_;
…		…
829		998
830	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	999	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
831		1000
832	# set environment to evaluate user expression	1001	# set environment to evaluate user expression
833		1002
834	local $self = $arg_self;	1003	local $self = $arg_self;
835
836	local $HOME = $ENV{HOME};	1004	local $HOME = $ENV{HOME};
837	local $old = $self->{state};	1005	local $frame = [];
838	local $new = my $state = $self->{state} = {};
839		1006
840	($x, $y, $w, $h) =
841	$self->background_geometry ($self->{border});	1007	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
842		1008
843	# evaluate user expression	1009	# evaluate user expression
844		1010
845	my $img = eval { $self->{expr}->() };	1011	my @img = eval { $self->{expr}->() };
846	warn $@ if $@;#d#	1012	die $@ if $@;
847	die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";	1013	die "background-expr did not return anything.\n" unless @img;
		1014	die "background-expr: expected image(s), got something else.\n"
		1015	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
848		1016
849	$state->{size_sensitive} = 1	1017	my $img = urxvt::bgdsl::merge @img;
		1018
		1019	$frame->[FR_AGAIN]{size} = 1
850	if $img->repeat_mode != urxvt::RepeatNormal;	1020	if $img->repeat_mode != urxvt::RepeatNormal;
851		1021
852	# if the expression is sensitive to external events, prepare reevaluation then	1022	# if the expression is sensitive to external events, prepare reevaluation then
853		1023	$self->compile_frame ($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	$self->disable ("rootpmap_change");
886	}
887		1024
888	# clear stuff we no longer need	1025	# clear stuff we no longer need
889		1026
890	%$old = ();	1027	# unless (%{ $frame->[FR_STATE] }) {
891
892	unless ($repeat) {
893	delete $self->{state};	1028	# delete $self->{state};
894	delete $self->{expr};	1029	# delete $self->{expr};
895	}	1030	# }
896		1031
897	# set background pixmap	1032	# set background pixmap
898		1033
899	$self->set_background ($img, $self->{border});	1034	$self->set_background ($img, $self->{border});
900	$self->scr_recolour (0);	1035	$self->scr_recolour (0);

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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 1.69 by root, Mon Jul 2 01:32:26 2012 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 1.69 by root, Mon Jul 2 01:32:26 2012 UTC