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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.54 by root, Thu Jun 14 16:22:20 2012 UTC vs.
Revision 1.71 by root, Mon Jul 2 01:40:41 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 is 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 COLOUR SPECIFICATIONS
142		163
143	As has been mentioned before, the expression might be evaluated multiple	164	Whenever an oprator expects a "colour", then this can be specified in one
144	times. Each time the expression is reevaluated, a new cycle is said to	165	of two ways: Either as string with an X11 colour specification, such as:
145	have begun. Many operators cache their results till the next cycle.
146		166
147	For example, the C<load> operator keeps a copy of the image. If it is	167	"red" # named colour
148	asked to load the same image on the next cycle it will not load it again,	168	"#f00" # simple rgb
149	but return the cached copy.	169	"[50]red" # red with 50% alpha
		170	"TekHVC:300/50/50" # anything goes
150		171
151	This only works for one cycle though, so as long as you load the same	172	OR as an array reference with one, three or four components:
152	image every time, it will always be cached, but when you load a different
153	image, it will forget about the first one.
154		173
155	This allows you to either speed things up by keeping multiple images in	174	[0.5] # 50% gray, 100% alpha
156	memory, or conserve memory by loading images more often.	175	[0.5, 0, 0] # dark red, no green or blur, 100% alpha
		176	[0.5, 0, 0, 0.7] # same with explicit 70% alpha
157		177
158	For example, you can keep two images in memory and use a random one like	178	=head2 CACHING AND SENSITIVITY
159	this:
160		179
161	my $img1 = load "img1.png";	180	Since some operations (such as C<load> and C<blur>) can take a long time,
162	my $img2 = load "img2.png";	181	caching results can be very important for a smooth operation. Caching can
163	(0.5 > rand) ? $img1 : $img2	182	also be useful to reduce memory usage, though, for example, when an image
		183	is cached by C<load>, it could be shared by multiple terminal windows
		184	running inside urxvtd.
164		185
165	Since both images are "loaded" every time the expression is evaluated,	186	=head3 C<keep { ... }> caching
166	they are always kept in memory. Contrast this version:
167		187
168	my $path1 = "img1.png";	188	The most important way to cache expensive operations is to use C<keep {
169	my $path2 = "img2.png";	189	... }>. The C<keep> operator takes a block of multiple statements enclosed
170	load ((0.5 > rand) ? $path1 : $path2)	190	by C<{}> and keeps the return value in memory.
171		191
172	Here, a path is selected randomly, and load is only called for one image,	192	An expression can be "sensitive" to various external events, such as
173	so keeps only one image in memory. If, on the next evaluation, luck	193	scaling or moving the window, root background changes and timers. Simply
174	decides to use the other path, then it will have to load that image again.	194	using an expression (such as C<scale> without parameters) that depends on
		195	certain changing values (called "variables"), or using those variables
		196	directly, will make an expression sensitive to these events - for example,
		197	using C<scale> or C<TW> will make the expression sensitive to the terminal
		198	size, and thus to resizing events.
		199
		200	When such an event happens, C<keep> will automatically trigger a
		201	reevaluation of the whole expression with the new value of the expression.
		202
		203	C<keep> is most useful for expensive operations, such as C<blur>:
		204
		205	rootalign keep { blur 20, root }
		206
		207	This makes a blurred copy of the root background once, and on subsequent
		208	calls, just root-aligns it. Since C<blur> is usually quite slow and
		209	C<rootalign> is quite fast, this trades extra memory (for the cached
		210	blurred pixmap) with speed (blur only needs to be redone when root
		211	changes).
		212
		213	=head3 C<load> caching
		214
		215	The C<load> operator itself does not keep images in memory, but as long as
		216	the image is still in memory, C<load> will use the in-memory image instead
		217	of loading it freshly from disk.
		218
		219	That means that this expression:
		220
		221	keep { load "$HOME/path..." }
		222
		223	Not only caches the image in memory, other terminal instances that try to
		224	C<load> it can reuse that in-memory copy.
175		225
176	=head1 REFERENCE	226	=head1 REFERENCE
177		227
178	=head2 COMMAND LINE SWITCHES	228	=head2 COMMAND LINE SWITCHES
179		229
…		…
203	=back	253	=back
204		254
205	=cut	255	=cut
206		256
207	our %_IMG_CACHE;	257	our %_IMG_CACHE;
208	our %_ONCE_CACHE;
209	our $HOME;	258	our $HOME;
210	our ($self, $old, $new);	259	our ($self, $frame);
211	our ($x, $y, $w, $h);	260	our ($x, $y, $w, $h);
212		261
213	# enforce at least this interval between updates	262	# enforce at least this interval between updates
214	our $MIN_INTERVAL = 6/59.951;	263	our $MIN_INTERVAL = 6/59.951;
215		264
216	{	265	{
217	package urxvt::bgdsl; # background language	266	package urxvt::bgdsl; # background language
		267
		268	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
		269	sub FR_CACHE () { 1 } # cached values
		270	sub FR_AGAIN () { 2 } # what this expr is sensitive to
		271	sub FR_STATE () { 3 } # watchers etc.
218		272
219	use List::Util qw(min max sum shuffle);	273	use List::Util qw(min max sum shuffle);
220		274
221	=head2 PROVIDERS/GENERATORS	275	=head2 PROVIDERS/GENERATORS
222		276
…		…
229	=item load $path	283	=item load $path
230		284
231	Loads the image at the given C<$path>. The image is set to plane tiling	285	Loads the image at the given C<$path>. The image is set to plane tiling
232	mode.	286	mode.
233		287
234	Loaded images will be cached for one cycle, and shared between temrinals	288	If the image is already in memory (e.g. because another terminal instance
235	running in the same process (e.g. in C<urxvtd>).	289	uses it), then the in-memory copy us returned instead.
236		290
237	=item load_uc $path	291	=item load_uc $path
238		292
239	Load uncached - same as load, but does not cache the image. This function	293	Load uncached - same as load, but does not cache the image, which means it
240	is most useufl if you want to optimise a background expression in some	294	is I<always> loaded from the filesystem again.
241	way.
242		295
243	=cut	296	=cut
244		297
245	sub load_uc($) {	298	sub load($) {
246	my ($path) = @_;	299	my ($path) = @_;
247		300
248	$_IMG_CACHE{$path} \|\| do {	301	$_IMG_CACHE{$path} \|\| do {
249	my $img = $self->new_img_from_file ($path);	302	my $img = $self->new_img_from_file ($path);
250	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);	303	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
251	$img	304	$img
252	}	305	}
253	}	306	}
254		307
255	sub load($) {
256	my ($path) = @_;
257
258	$new->{load}{$path} = $old->{load}{$path} \|\| load_uc $path;
259	}
260
261	=item root	308	=item root
262		309
263	Returns the root window pixmap, that is, hopefully, the background image	310	Returns the root window pixmap, that is, hopefully, the background image
264	of your screen. The image is set to extend mode.	311	of your screen.
265		312
266	This function makes your expression root sensitive, that means it will be	313	This function makes your expression root sensitive, that means it will be
267	reevaluated when the bg image changes.	314	reevaluated when the bg image changes.
268		315
269	=cut	316	=cut
270		317
271	sub root() {	318	sub root() {
272	$new->{rootpmap_sensitive} = 1;	319	$frame->[FR_AGAIN]{rootpmap} = 1;
273	$self->new_img_from_root	320	$self->new_img_from_root
274	}	321	}
275		322
276	=item solid $colour	323	=item solid $colour
277		324
…		…
286	=cut	333	=cut
287		334
288	sub solid($;$$) {	335	sub solid($;$$) {
289	my $colour = pop;	336	my $colour = pop;
290		337
291	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	338	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
292	$img->fill ($colour);	339	$img->fill ($colour);
293	$img	340	$img
294	}	341	}
295		342
296	=item clone $img	343	=item clone $img
…		…
300		347
301	=cut	348	=cut
302		349
303	sub clone($) {	350	sub clone($) {
304	$_[0]->clone	351	$_[0]->clone
		352	}
		353
		354	=item merge $img ...
		355
		356	Takes any number of images and merges them together, creating a single
		357	image containing them all. The tiling mode of the first image is used as
		358	the tiling mode of the resulting image.
		359
		360	This function is called automatically when an expression returns multiple
		361	images.
		362
		363	=cut
		364
		365	sub merge(@) {
		366	return $_[0] unless $#_;
		367
		368	# rather annoyingly clumsy, but optimisation is for another time
		369
		370	my $x0 = +1e9;
		371	my $y0 = +1e9;
		372	my $x1 = -1e9;
		373	my $y1 = -1e9;
		374
		375	for (@_) {
		376	my ($x, $y, $w, $h) = $_->geometry;
		377
		378	$x0 = $x if $x0 > $x;
		379	$y0 = $y if $y0 > $y;
		380
		381	$x += $w;
		382	$y += $h;
		383
		384	$x1 = $x if $x1 < $x;
		385	$y1 = $y if $y1 < $y;
		386	}
		387
		388	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		389	$base->repeat_mode ($_[0]->repeat_mode);
		390	$base->fill ([0, 0, 0, 0]);
		391
		392	$base->draw ($_)
		393	for @_;
		394
		395	$base
305	}	396	}
306		397
307	=head2 TILING MODES	398	=head2 TILING MODES
308		399
309	The following operators modify the tiling mode of an image, that is, the	400	The following operators modify the tiling mode of an image, that is, the
…		…
407	Using these functions make your expression sensitive to window moves.	498	Using these functions make your expression sensitive to window moves.
408		499
409	These functions are mainly useful to align images to the root window.	500	These functions are mainly useful to align images to the root window.
410		501
411	Example: load an image and align it so it looks as if anchored to the	502	Example: load an image and align it so it looks as if anchored to the
412	background.	503	background (that's exactly what C<rootalign> does btw.):
413		504
414	move -TX, -TY, load "mybg.png"	505	move -TX, -TY, keep { load "mybg.png" }
415		506
416	=item TW	507	=item TW
417		508
418	Return the width (C<TW>) and height (C<TH>) of the terminal window (the	509	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
419	terminal window is the full window by default, and the character area only	510	terminal window is the full window by default, and the character area only
…		…
425	the window size to conserve memory.	516	the window size to conserve memory.
426		517
427	Example: take the screen background, clip it to the window size, blur it a	518	Example: take the screen background, clip it to the window size, blur it a
428	bit, align it to the window position and use it as background.	519	bit, align it to the window position and use it as background.
429		520
430	clip move -TX, -TY, blur 5, root	521	clip move -TX, -TY, keep { blur 5, root }
431		522
432	=cut	523	=cut
433		524
434	sub TX() { $new->{position_sensitive} = 1; $x }	525	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
435	sub TY() { $new->{position_sensitive} = 1; $y }	526	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
436	sub TW() { $new->{size_sensitive} = 1; $w }	527	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
437	sub TH() { $new->{size_sensitive} = 1; $h }	528	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
438		529
439	=item now	530	=item now
440		531
441	Returns the current time as (fractional) seconds since the epoch.	532	Returns the current time as (fractional) seconds since the epoch.
442		533
…		…
449	C<$seconds> seconds.	540	C<$seconds> seconds.
450		541
451	Example: load some image and rotate it according to the time of day (as if it were	542	Example: load some image and rotate it according to the time of day (as if it were
452	the hour pointer of a clock). Update this image every minute.	543	the hour pointer of a clock). Update this image every minute.
453		544
		545	again 60;
454	again 60; rotate 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"	546	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
455		547
456	=item counter $seconds	548	=item counter $seconds
457		549
458	Like C<again>, but also returns an increasing counter value, starting at	550	Like C<again>, but also returns an increasing counter value, starting at
459	0, which might be useful for some simple animation effects.	551	0, which might be useful for some simple animation effects.
…		…
461	=cut	553	=cut
462		554
463	sub now() { urxvt::NOW }	555	sub now() { urxvt::NOW }
464		556
465	sub again($) {	557	sub again($) {
466	$new->{again} = $_[0];	558	$frame->[FR_AGAIN]{time} = $_[0];
467	}	559	}
468		560
469	sub counter($) {	561	sub counter($) {
470	$new->{again} = $_[0];	562	$frame->[FR_AGAIN]{time} = $_[0];
471	$self->{counter} + 0	563	$frame->[FR_STATE]{counter} + 0
472	}	564	}
473		565
474	=back	566	=back
475		567
476	=head2 SHAPE CHANGING OPERATORS	568	=head2 SHAPE CHANGING OPERATORS
…		…
496	assumed.	588	assumed.
497		589
498	Example: load an image, blur it, and clip it to the window size to save	590	Example: load an image, blur it, and clip it to the window size to save
499	memory.	591	memory.
500		592
501	clip blur 10, load "mybg.png"	593	clip keep { blur 10, load "mybg.png" }
502		594
503	=cut	595	=cut
504		596
505	sub clip($;$$;$$) {	597	sub clip($;$$;$$) {
506	my $img = pop;	598	my $img = pop;
…		…
600	the terminal window (or the box specified by C<$width> and C<$height> if	692	the terminal window (or the box specified by C<$width> and C<$height> if
601	given).	693	given).
602		694
603	Example: load an image and center it.	695	Example: load an image and center it.
604		696
605	center pad load "mybg.png"	697	center keep { pad load "mybg.png" }
606		698
607	=item rootalign $img	699	=item rootalign $img
608		700
609	Moves the image so that it appears glued to the screen as opposed to the	701	Moves the image so that it appears glued to the screen as opposed to the
610	window. This gives the illusion of a larger area behind the window. It is	702	window. This gives the illusion of a larger area behind the window. It is
611	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	703	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
612	top left of the screen.	704	top left of the screen.
613		705
614	Example: load a background image, put it in mirror mode and root align it.	706	Example: load a background image, put it in mirror mode and root align it.
615		707
616	rootalign mirror load "mybg.png"	708	rootalign keep { mirror load "mybg.png" }
617		709
618	Example: take the screen background and align it, giving the illusion of	710	Example: take the screen background and align it, giving the illusion of
619	transparency as long as the window isn't in front of other windows.	711	transparency as long as the window isn't in front of other windows.
620		712
621	rootalign root	713	rootalign root
…		…
646		738
647	sub rootalign($) {	739	sub rootalign($) {
648	move -TX, -TY, $_[0]	740	move -TX, -TY, $_[0]
649	}	741	}
650		742
651	=item rotate $center_x, $center_y, $degrees	743	=item rotate $center_x, $center_y, $degrees, $img
652		744
653	Rotates the image by C<$degrees> degrees, counter-clockwise, around the	745	Rotates the image clockwise by C<$degrees> degrees, around the point at
654	pointer at C<$center_x> and C<$center_y> (specified as factor of image	746	C<$center_x> and C<$center_y> (specified as factor of image width/height).
655	width/height).
656		747
657	#TODO# new width, height, maybe more operators?
658
659	Example: rotate the image by 90 degrees	748	Example: rotate the image by 90 degrees around it's center.
		749
		750	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
660		751
661	=cut	752	=cut
662		753
663	sub rotate($$$$) {	754	sub rotate($$$$) {
664	my $img = pop;	755	my $img = pop;
665	$img->rotate (	756	$img->rotate (
666	$_[0] * $img->w,	757	$_[0] * ($img->w + $img->x),
667	$_[1] * $img->h,	758	$_[1] * ($img->h + $img->y),
668	$_[2] * (3.14159265 / 180),	759	$_[2] * (3.14159265 / 180),
669	)	760	)
670	}	761	}
671		762
672	=back	763	=back
…		…
674	=head2 COLOUR MODIFICATIONS	765	=head2 COLOUR MODIFICATIONS
675		766
676	The following operators change the pixels of the image.	767	The following operators change the pixels of the image.
677		768
678	=over 4	769	=over 4
		770
		771	=item tint $color, $img
		772
		773	Tints the image in the given colour.
		774
		775	Example: tint the image red.
		776
		777	tint "red", load "rgb.png"
		778
		779	Example: the same, but specify the colour by component.
		780
		781	tint [1, 0, 0], load "rgb.png"
		782
		783	=cut
		784
		785	sub tint($$) {
		786	$_[1]->tint ($_[0])
		787	}
679		788
680	=item contrast $factor, $img	789	=item contrast $factor, $img
681		790
682	=item contrast $r, $g, $b, $img	791	=item contrast $r, $g, $b, $img
683		792
…		…
762		871
763	=back	872	=back
764		873
765	=head2 OTHER STUFF	874	=head2 OTHER STUFF
766		875
767	Anything that didn't fit any of the other categories, even after appliyng	876	Anything that didn't fit any of the other categories, even after applying
768	force and closing our eyes.	877	force and closing our eyes.
769		878
770	=over 4	879	=over 4
771		880
772	=item once { ... }	881	=item keep { ... }
773		882
774	This function takes a code block as argument, that is, one or more	883	This operator takes a code block as argument, that is, one or more
775	statements enclosed by braces.	884	statements enclosed by braces.
776		885
777	The trick is that this code block is only evaluated once - future calls	886	The trick is that this code block is only evaluated when the outcome
778	will simply return the original image (yes, it should only be used with	887	changes - on other calls the C<keep> simply returns the image it computed
779	images).	888	previously (yes, it should only be used with images). Or in other words,
		889	C<keep> I<caches> the result of the code block so it doesn't need to be
		890	computed again.
780		891
781	This can be extremely useful to avoid redoign the same slow operations	892	This can be extremely useful to avoid redoing slow operations - for
782	again and again- for example, if your background expression takes the root	893	example, if your background expression takes the root background, blurs it
783	background, blurs it and then root-aligns it it would have to blur the	894	and then root-aligns it it would have to blur the root background on every
784	root background on every window move or resize.	895	window move or resize.
785		896
		897	Another example is C<load>, which can be quite slow.
		898
		899	In fact, urxvt itself encloses the whole expression in some kind of
		900	C<keep> block so it only is reevaluated as required.
		901
786	Putting the blur into a C<once> block will make sure the blur is only done	902	Putting the blur into a C<keep> block will make sure the blur is only done
787	once:	903	once, while the C<rootalign> is still done each time the window moves.
788		904
789	rootlign once { blur 10, root }	905	rootlign keep { blur 10, root }
790		906
791	This leaves the question of how to force reevaluation of the block, in	907	This leaves the question of how to force reevaluation of the block,
792	case the root background changes: Right now, all once blocks forget that	908	in case the root background changes: If expression inside the block
793	they ahve been executed before each time the root background changes (if	909	is sensitive to some event (root background changes, window geometry
794	the expression is sensitive to that) or when C<once_again> is called.	910	changes), then it will be reevaluated automatically as needed.
795		911
796	=item once_again
797
798	Resets all C<once> block as if they had never been called, i.e. on the
799	next call they will be reevaluated again.
800
801	=cut	912	=cut
802		913
803	sub once(&) {	914	sub keep(&) {
804	$_ONCE_CACHE{$_[0]+0} \|\|= $_[0]()	915	my $id = $_[0]+0;
		916
		917	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		918
		919	unless ($frame->[FR_CACHE]) {
		920	$frame->[FR_CACHE] = [ $_[0]() ];
		921
		922	my $self = $self;
		923	my $frame = $frame;
		924	Scalar::Util::weaken $frame;
		925	$self->compile_frame ($frame, sub {
		926	# clear this frame cache, also for all parents
		927	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		928	undef $frame->[FR_CACHE];
		929	}
		930
		931	$self->recalculate;
		932	});
		933	};
		934
		935	# in scalar context we always return the first original result, which
		936	# is not quite how perl works.
		937	wantarray
		938	? @{ $frame->[FR_CACHE] }
		939	: $frame->[FR_CACHE][0]
		940	}
		941
		942	# sub keep_clear() {
		943	# delete $self->{frame_cache};
805	}	944	# }
806
807	sub once_again() {
808	%_ONCE_CACHE = ();
809	}
810		945
811	=back	946	=back
812		947
813	=cut	948	=cut
814		949
815	}	950	}
816		951
817	sub parse_expr {	952	sub parse_expr {
818	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	953	my $expr = eval
		954	"sub {\n"
		955	. "package urxvt::bgdsl;\n"
		956	. "#line 0 'background expression'\n"
		957	. "$_[0]\n"
		958	. "}";
819	die if $@;	959	die if $@;
820	$expr	960	$expr
821	}	961	}
822		962
823	# compiles a parsed expression	963	# compiles a parsed expression
824	sub set_expr {	964	sub set_expr {
825	my ($self, $expr) = @_;	965	my ($self, $expr) = @_;
826		966
		967	$self->{root} = [];
827	$self->{expr} = $expr;	968	$self->{expr} = $expr;
828	$self->recalculate;	969	$self->recalculate;
		970	}
		971
		972	# takes a hash of sensitivity indicators and installs watchers
		973	sub compile_frame {
		974	my ($self, $frame, $cb) = @_;
		975
		976	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		977	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		978
		979	# don't keep stuff alive
		980	Scalar::Util::weaken $state;
		981
		982	if ($again->{nested}) {
		983	$state->{nested} = 1;
		984	} else {
		985	delete $state->{nested};
		986	}
		987
		988	if (my $interval = $again->{time}) {
		989	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		990	if $state->{time}[0] != $interval;
		991
		992	# callback might have changed, although we could just rule that out
		993	$state->{time}[1]->cb (sub {
		994	++$state->{counter};
		995	$cb->();
		996	});
		997	} else {
		998	delete $state->{time};
		999	}
		1000
		1001	if ($again->{position}) {
		1002	$state->{position} = $self->on (position_change => $cb);
		1003	} else {
		1004	delete $state->{position};
		1005	}
		1006
		1007	if ($again->{size}) {
		1008	$state->{size} = $self->on (size_change => $cb);
		1009	} else {
		1010	delete $state->{size};
		1011	}
		1012
		1013	if ($again->{rootpmap}) {
		1014	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		1015	} else {
		1016	delete $state->{rootpmap};
		1017	}
829	}	1018	}
830		1019
831	# evaluate the current bg expression	1020	# evaluate the current bg expression
832	sub recalculate {	1021	sub recalculate {
833	my ($arg_self) = @_;	1022	my ($arg_self) = @_;
…		…
843		1032
844	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1033	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
845		1034
846	# set environment to evaluate user expression	1035	# set environment to evaluate user expression
847		1036
848	local $self = $arg_self;	1037	local $self = $arg_self;
849
850	local $HOME = $ENV{HOME};	1038	local $HOME = $ENV{HOME};
851	local $old = $self->{state};	1039	local $frame = [];
852	local $new = my $state = $self->{state} = {};
853		1040
854	($x, $y, $w, $h) =
855	$self->background_geometry ($self->{border});	1041	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
856		1042
857	# evaluate user expression	1043	# evaluate user expression
858		1044
859	my $img = eval { $self->{expr}->() };	1045	my @img = eval { $self->{expr}->() };
860	warn $@ if $@;#d#	1046	die $@ if $@;
861	die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";	1047	die "background-expr did not return anything.\n" unless @img;
		1048	die "background-expr: expected image(s), got something else.\n"
		1049	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
862		1050
863	$state->{size_sensitive} = 1	1051	my $img = urxvt::bgdsl::merge @img;
		1052
		1053	$frame->[FR_AGAIN]{size} = 1
864	if $img->repeat_mode != urxvt::RepeatNormal;	1054	if $img->repeat_mode != urxvt::RepeatNormal;
865		1055
866	# if the expression is sensitive to external events, prepare reevaluation then	1056	# if the expression is sensitive to external events, prepare reevaluation then
867		1057	$self->compile_frame ($frame, sub { $arg_self->recalculate });
868	my $repeat;
869
870	if (my $again = $state->{again}) {
871	$repeat = 1;
872	my $self = $self;
873	$state->{timer} = $again == $old->{again}
874	? $old->{timer}
875	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
876	++$self->{counter};
877	$self->recalculate
878	});
879	}
880
881	if (delete $state->{position_sensitive}) {
882	$repeat = 1;
883	$self->enable (position_change => sub { $_[0]->recalculate });
884	} else {
885	$self->disable ("position_change");
886	}
887
888	if (delete $state->{size_sensitive}) {
889	$repeat = 1;
890	$self->enable (size_change => sub { $_[0]->recalculate });
891	} else {
892	$self->disable ("size_change");
893	}
894
895	if (delete $state->{rootpmap_sensitive}) {
896	$repeat = 1;
897	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
898	} else {
899	$self->disable ("rootpmap_change");
900	}
901		1058
902	# clear stuff we no longer need	1059	# clear stuff we no longer need
903		1060
904	%$old = ();	1061	# unless (%{ $frame->[FR_STATE] }) {
905
906	unless ($repeat) {
907	delete $self->{state};	1062	# delete $self->{state};
908	delete $self->{expr};	1063	# delete $self->{expr};
909	}	1064	# }
910		1065
911	# set background pixmap	1066	# set background pixmap
912		1067
913	$self->set_background ($img, $self->{border});	1068	$self->set_background ($img, $self->{border});
914	$self->scr_recolour (0);	1069	$self->scr_recolour (0);

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.54 by root, Thu Jun 14 16:22:20 2012 UTC vs. Revision 1.71 by root, Mon Jul 2 01:40:41 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.54 by root, Thu Jun 14 16:22:20 2012 UTC vs.
Revision 1.71 by root, Mon Jul 2 01:40:41 2012 UTC