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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.48 by root, Sun Jun 10 15:01:14 2012 UTC vs.
Revision 1.69 by root, Mon Jul 2 01:32:26 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
…		…
28	to be as simple as possible.	26	to be as simple as possible.
29		27
30	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
31	use:	29	use:
32		30
33	urxvt --background-expr 'scale load "/path/to/mybg.png"'	31	urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
34		32
35	Or specified as a X resource:	33	Or specified as a X resource:
36		34
37	URxvt.background-expr: scale load "/path/to/mybg.png"	35	URxvt.background-expr: scale keep { load "/path/to/mybg.png" }
38		36
39	=head1 THEORY OF OPERATION	37	=head1 THEORY OF OPERATION
40		38
41	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
42	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
…		…
55	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
56	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
57	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
58	timer elapses), then the expression will be evaluated again.	56	timer elapses), then the expression will be evaluated again.
59		57
60	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"
61	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
62	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
63	example. That ensures that the picture always fills the terminal, even	61	example. That ensures that the picture always fills the terminal, even
64	after it's size changes.	62	after its size changes.
65		63
66	=head2 EXPRESSIONS	64	=head2 EXPRESSIONS
67		65
68	Expressions are normal Perl expressions, in fact, they are Perl blocks -	66	Expressions are normal Perl expressions, in fact, they are Perl blocks -
69	which means you could use multiple lines and statements:	67	which means you could use multiple lines and statements:
70		68
		69	scale keep {
71	again 3600;	70	again 3600;
72	if (localtime now)[6]) {	71	if (localtime now)[6]) {
73	return scale load "$HOME/weekday.png";	72	return load "$HOME/weekday.png";
74	} else {	73	} else {
75	return scale load "$HOME/sunday.png";	74	return load "$HOME/sunday.png";
		75	}
76	}	76	}
77		77
78	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
79	background on Sundays, and F<weekday.png> on all other days.	80	Sundays, and F<weekday.png> on all other days.
80		81
81	Fortunately, we expect that most expressions will be much simpler, with	82	Fortunately, we expect that most expressions will be much simpler, with
82	little Perl knowledge needed.	83	little Perl knowledge needed.
83		84
84	Basically, you always start with a function that "generates" an image	85	Basically, you always start with a function that "generates" an image
…		…
117	horizontal and vertical dimensions. For example, this halves the image	118	horizontal and vertical dimensions. For example, this halves the image
118	width and doubles the image height:	119	width and doubles the image height:
119		120
120	scale 0.5, 2, load "$HOME/mypic.png"	121	scale 0.5, 2, load "$HOME/mypic.png"
121		122
122	Other effects than scalign are also readily available, for exmaple, you can	123	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:	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:
124		127
		128	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		129
		130	The C<keep> operator executes all the statements inside the braces only
		131	once, or when it thinks the outcome might change. In other cases it
		132	returns the last value computed by the brace block.
		133
		134	This means that the C<load> is only executed once, which makes it much
		135	faster, but also means that more memory is being used, because the loaded
		136	image must be kept in memory at all times. In this expression, the
		137	trade-off is likely worth it.
		138
		139	But back to effects: Other effects than scaling are also readily
		140	available, for example, you can tile the image to fill the whole window,
		141	instead of resizing it:
		142
125	tile load "$HOME/mypic.png"	143	tile keep { load "$HOME/mypic.png" }
126		144
127	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator	145	In fact, images returned by C<load> are in C<tile> mode by default, so the
128	is kind of superfluous.	146	C<tile> operator is kind of superfluous.
129		147
130	Another common effect is to mirror the image, so that the same edges touch:	148	Another common effect is to mirror the image, so that the same edges
		149	touch:
131		150
132	mirror load "$HOME/mypic.png"	151	mirror keep { load "$HOME/mypic.png" }
133		152
134	This is also a typical background expression:	153	Another common background expression is:
135		154
136	rootalign root	155	rootalign root
137		156
138	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
139	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
140	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:
141	moved around.	160	the image seems to be static while the window is moved around.
142		161
143	=head2 CYCLES AND CACHING	162	=head2 CACHING AND SENSITIVITY
144		163
145	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,
146	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
147	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.
148		169
149	For example, the C<load> operator keeps a copy of the image. If it is	170	=head3 C<keep { ... }> caching
150	asked to load the same image on the next cycle it will not load it again,
151	but return the cached copy.
152		171
153	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 {
154	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
155	image, it will forget about the first one.	174	by C<{}> and keeps the return value in memory.
156		175
157	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
158	memory, or comserve 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.
159		183
160	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
161	this:	185	reevaluation of the whole expression with the new value of the expression.
162		186
163	my $img1 = load "img1.png";	187	C<keep> is most useful for expensive operations, such as C<blur>:
164	my $img2 = load "img2.png";
165	(0.5 > rand) ? $img1 : $img2
166		188
167	Since both images are "loaded" every time the expression is evaluated,	189	rootalign keep { blur 20, root }
168	they are always kept in memory. Contrast this version:
169		190
170	my $path1 = "img1.png";	191	This makes a blurred copy of the root background once, and on subsequent
171	my $path2 = "img2.png";	192	calls, just root-aligns it. Since C<blur> is usually quite slow and
172	load ((0.5 > rand) ? $path1 : $path2)	193	C<rootalign> is quite fast, this trades extra memory (for the cached
		194	blurred pixmap) with speed (blur only needs to be redone when root
		195	changes).
173		196
174	Here, a path is selected randomly, and load is only called for one image,	197	=head3 C<load> caching
175	so keeps only one image in memory. If, on the next evaluation, luck	198
176	decides to use the other path, then it will have to load that image again.	199	The C<load> operator itself does not keep images in memory, but as long as
		200	the image is still in memory, C<load> will use the in-memory image instead
		201	of loading it freshly from disk.
		202
		203	That means that this expression:
		204
		205	keep { load "$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.
177		209
178	=head1 REFERENCE	210	=head1 REFERENCE
179		211
180	=head2 COMMAND LINE SWITCHES	212	=head2 COMMAND LINE SWITCHES
181		213
…		…
193	Specifying this flag changes the behaviour, so that the image only	225	Specifying this flag changes the behaviour, so that the image only
194	replaces the background of the character area.	226	replaces the background of the character area.
195		227
196	=item --background-interval seconds	228	=item --background-interval seconds
197		229
198	Since some operations in the underlying XRender extension can effetively	230	Since some operations in the underlying XRender extension can effectively
199	freeze your X-server for prolonged time, this extension enforces a minimum	231	freeze your X-server for prolonged time, this extension enforces a minimum
200	time between updates, which is normally about 0.1 seconds.	232	time between updates, which is normally about 0.1 seconds.
201		233
202	If you want to do updates more often, you can decrease this safety	234	If you want to do updates more often, you can decrease this safety
203	interval with this switch.	235	interval with this switch.
204		236
205	=back	237	=back
206		238
207	=cut	239	=cut
208		240
		241	our %_IMG_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	die "root op not supported, exg, we need you";	304	$self->new_img_from_root
257	}	305	}
258		306
259	=item solid $colour	307	=item solid $colour
260		308
261	=item solid $width, $height, $colour	309	=item solid $width, $height, $colour
…		…
269	=cut	317	=cut
270		318
271	sub solid($;$$) {	319	sub solid($;$$) {
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 $img
…		…
285		333
286	sub clone($) {	334	sub clone($) {
287	$_[0]->clone	335	$_[0]->clone
288	}	336	}
289		337
290	=back	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
		380	}
291		381
292	=head2 TILING MODES	382	=head2 TILING MODES
293		383
294	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
295	way that pixels outside the image area are painted when the image is used.	385	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	415	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	416	image over another image or the background colour while leaving all
327	background pixels outside the image unchanged.	417	background pixels outside the image unchanged.
328		418
329	Example: load an image and display it in the upper left corner. The rest	419	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	420	of the space is left "empty" (transparent or whatever your compositor does
331	in alpha mode, else background colour).	421	in alpha mode, else background colour).
332		422
333	pad load "mybg.png"	423	pad load "mybg.png"
334		424
335	=item extend $img	425	=item extend $img
336		426
337	Extends the image over the whole plane, using the closest pixel in the	427	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	428	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	429	filtering operations and want the pixels outside the image to have the
340	same values as the pixels near the edge.	430	same values as the pixels near the edge.
341		431
342	Example: just for curiosity, how does this pixel extension stuff work?	432	Example: just for curiosity, how does this pixel extension stuff work?
343		433
…		…
392	Using these functions make your expression sensitive to window moves.	482	Using these functions make your expression sensitive to window moves.
393		483
394	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.
395		485
396	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
397	background.	487	background (that's exactly what C<rootalign> does btw.):
398		488
399	move -TX, -TY, load "mybg.png"	489	move -TX, -TY, keep { load "mybg.png" }
400		490
401	=item TW	491	=item TW
402		492
403	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
404	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
…		…
410	the window size to conserve memory.	500	the window size to conserve memory.
411		501
412	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
413	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.
414		504
415	clip move -TX, -TY, blur 5, root	505	clip move -TX, -TY, keep { blur 5, root }
416		506
417	=cut	507	=cut
418		508
419	sub TX() { $new->{position_sensitive} = 1; $x }	509	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
420	sub TY() { $new->{position_sensitive} = 1; $y }	510	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
421	sub TW() { $new->{size_sensitive} = 1; $w }	511	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
422	sub TH() { $new->{size_sensitive} = 1; $h }	512	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
423		513
424	=item now	514	=item now
425		515
426	Returns the current time as (fractional) seconds since the epoch.	516	Returns the current time as (fractional) seconds since the epoch.
427		517
…		…
434	C<$seconds> seconds.	524	C<$seconds> seconds.
435		525
436	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
437	the hour pointer of a clock). Update this image every minute.	527	the hour pointer of a clock). Update this image every minute.
438		528
		529	again 60;
439	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" }
440		531
441	=item counter $seconds	532	=item counter $seconds
442		533
443	Like C<again>, but also returns an increasing counter value, starting at	534	Like C<again>, but also returns an increasing counter value, starting at
444	0, which might be useful for some simple animation effects.	535	0, which might be useful for some simple animation effects.
…		…
446	=cut	537	=cut
447		538
448	sub now() { urxvt::NOW }	539	sub now() { urxvt::NOW }
449		540
450	sub again($) {	541	sub again($) {
451	$new->{again} = $_[0];	542	$frame->[FR_AGAIN]{time} = $_[0];
452	}	543	}
453		544
454	sub counter($) {	545	sub counter($) {
455	$new->{again} = $_[0];	546	$frame->[FR_AGAIN]{time} = $_[0];
456	$self->{counter} + 0	547	$frame->[FR_STATE]{counter} + 0
457	}	548	}
458		549
459	=back	550	=back
460		551
461	=head2 SHAPE CHANGING OPERATORS	552	=head2 SHAPE CHANGING OPERATORS
…		…
481	assumed.	572	assumed.
482		573
483	Example: load an image, blur it, and clip it to the window size to save	574	Example: load an image, blur it, and clip it to the window size to save
484	memory.	575	memory.
485		576
486	clip blur 10, load "mybg.png"	577	clip keep { blur 10, load "mybg.png" }
487		578
488	=cut	579	=cut
489		580
490	sub clip($;$$;$$) {	581	sub clip($;$$;$$) {
491	my $img = pop;	582	my $img = pop;
…		…
585	the terminal window (or the box specified by C<$width> and C<$height> if	676	the terminal window (or the box specified by C<$width> and C<$height> if
586	given).	677	given).
587		678
588	Example: load an image and center it.	679	Example: load an image and center it.
589		680
590	center pad load "mybg.png"	681	center keep { pad load "mybg.png" }
591		682
592	=item rootalign $img	683	=item rootalign $img
593		684
594	Moves the image so that it appears glued to the screen as opposed to the	685	Moves the image so that it appears glued to the screen as opposed to the
595	window. This gives the illusion of a larger area behind the window. It is	686	window. This gives the illusion of a larger area behind the window. It is
596	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	687	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
597	top left of the screen.	688	top left of the screen.
598		689
599	Example: load a background image, put it in mirror mode and root align it.	690	Example: load a background image, put it in mirror mode and root align it.
600		691
601	rootalign mirror load "mybg.png"	692	rootalign keep { mirror load "mybg.png" }
602		693
603	Example: take the screen background and align it, giving the illusion of	694	Example: take the screen background and align it, giving the illusion of
604	transparency as long as the window isn't in front of other windows.	695	transparency as long as the window isn't in front of other windows.
605		696
606	rootalign root	697	rootalign root
…		…
631		722
632	sub rootalign($) {	723	sub rootalign($) {
633	move -TX, -TY, $_[0]	724	move -TX, -TY, $_[0]
634	}	725	}
635		726
		727	=item rotate $center_x, $center_y, $degrees, $img
		728
		729	Rotates the image clockwise by C<$degrees> degrees, around the point at
		730	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		731
		732	Example: rotate the image by 90 degrees around it's center.
		733
		734	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		735
		736	=cut
		737
		738	sub rotate($$$$) {
		739	my $img = pop;
		740	$img->rotate (
		741	$_[0] * ($img->w + $img->x),
		742	$_[1] * ($img->h + $img->y),
		743	$_[2] * (3.14159265 / 180),
		744	)
		745	}
		746
636	=back	747	=back
637		748
638	=head2 COLOUR MODIFICATIONS	749	=head2 COLOUR MODIFICATIONS
639		750
640	The following operators change the pixels of the image.	751	The following operators change the pixels of the image.
…		…
674		785
675	Values less than 0 reduce brightness, while values larger than 0 increase	786	Values less than 0 reduce brightness, while values larger than 0 increase
676	it. Useful range is from -1 to 1 - the former results in a black, the	787	it. Useful range is from -1 to 1 - the former results in a black, the
677	latter in a white picture.	788	latter in a white picture.
678		789
679	Due to idiosynchrasies in the underlying XRender extension, biases less	790	Due to idiosyncrasies in the underlying XRender extension, biases less
680	than zero can be I<very> slow.	791	than zero can be I<very> slow.
681		792
682	=cut	793	=cut
683		794
684	sub contrast($$;$$;$) {	795	sub contrast($$;$$;$) {
685	my $img = pop;	796	my $img = pop;
686	my ($r, $g, $b, $a) = @_;	797	my ($r, $g, $b, $a) = @_;
687		798
688	($g, $b) = ($r, $r) if @_ < 4;	799	($g, $b) = ($r, $r) if @_ < 3;
689	$a = 1 if @_ < 5;	800	$a = 1 if @_ < 4;
690		801
691	$img = $img->clone;	802	$img = $img->clone;
692	$img->contrast ($r, $g, $b, $a);	803	$img->contrast ($r, $g, $b, $a);
693	$img	804	$img
694	}	805	}
695		806
696	sub brightness($$;$$;$) {	807	sub brightness($$;$$;$) {
697	my $img = pop;	808	my $img = pop;
698	my ($r, $g, $b, $a) = @_;	809	my ($r, $g, $b, $a) = @_;
699		810
700	($g, $b) = ($r, $r) if @_ < 4;	811	($g, $b) = ($r, $r) if @_ < 3;
701	$a = 1 if @_ < 5;	812	$a = 1 if @_ < 4;
702		813
703	$img = $img->clone;	814	$img = $img->clone;
704	$img->brightness ($r, $g, $b, $a);	815	$img->brightness ($r, $g, $b, $a);
705	$img	816	$img
706	}	817	}
…		…
722	sub blur($$;$) {	833	sub blur($$;$) {
723	my $img = pop;	834	my $img = pop;
724	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	835	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
725	}	836	}
726		837
727	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
728
729	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
730	pointer at C<$center_x> and C<$center_y> (specified as factor of image
731	width/height), generating a new image with width C<$new_width> and height
732	C<$new_height>.
733
734	#TODO# new width, height, maybe more operators?
735
736	Example: rotate the image by 90 degrees
737
738	=cut
739
740	sub rotate($$$$$$) {
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	838	=back
752		839
		840	=head2 OTHER STUFF
		841
		842	Anything that didn't fit any of the other categories, even after applying
		843	force and closing our eyes.
		844
		845	=over 4
		846
		847	=item keep { ... }
		848
		849	This operator takes a code block as argument, that is, one or more
		850	statements enclosed by braces.
		851
		852	The trick is that this code block is only evaluated when the outcome
		853	changes - on other calls the C<keep> simply returns the image it computed
		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.
		857
		858	This can be extremely useful to avoid redoing slow operations - for
		859	example, if your background expression takes the root background, blurs it
		860	and then root-aligns it it would have to blur the root background on every
		861	window move or resize.
		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
		868	Putting the blur into a C<keep> block will make sure the blur is only done
		869	once, while the C<rootalign> is still done each time the window moves.
		870
		871	rootlign keep { blur 10, root }
		872
		873	This leaves the question of how to force reevaluation of the block,
		874	in case the root background changes: If expression inside the block
		875	is sensitive to some event (root background changes, window geometry
		876	changes), then it will be reevaluated automatically as needed.
		877
		878	=cut
		879
		880	sub keep(&) {
		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};
		910	# }
		911
		912	=back
		913
753	=cut	914	=cut
754		915
755	}	916	}
756		917
757	sub parse_expr {	918	sub parse_expr {
758	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	. "}";
759	die if $@;	925	die if $@;
760	$expr	926	$expr
761	}	927	}
762		928
763	# compiles a parsed expression	929	# compiles a parsed expression
764	sub set_expr {	930	sub set_expr {
765	my ($self, $expr) = @_;	931	my ($self, $expr) = @_;
766		932
		933	$self->{root} = [];
767	$self->{expr} = $expr;	934	$self->{expr} = $expr;
768	$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 $state->{rootpmap};
		983	}
769	}	984	}
770		985
771	# evaluate the current bg expression	986	# evaluate the current bg expression
772	sub recalculate {	987	sub recalculate {
773	my ($arg_self) = @_;	988	my ($arg_self) = @_;
…		…
783		998
784	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	999	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
785		1000
786	# set environment to evaluate user expression	1001	# set environment to evaluate user expression
787		1002
788	local $self = $arg_self;	1003	local $self = $arg_self;
789
790	local $HOME = $ENV{HOME};	1004	local $HOME = $ENV{HOME};
791	local $old = $self->{state};	1005	local $frame = [];
792	local $new = my $state = $self->{state} = {};
793		1006
794	($x, $y, $w, $h) =
795	$self->background_geometry ($self->{border});	1007	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
796		1008
797	# evaluate user expression	1009	# evaluate user expression
798		1010
799	my $img = eval { $self->{expr}->() };	1011	my @img = eval { $self->{expr}->() };
800	warn $@ if $@;#d#	1012	die $@ if $@;
801	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;
802		1016
803	$state->{size_sensitive} = 1	1017	my $img = urxvt::bgdsl::merge @img;
		1018
		1019	$frame->[FR_AGAIN]{size} = 1
804	if $img->repeat_mode != urxvt::RepeatNormal;	1020	if $img->repeat_mode != urxvt::RepeatNormal;
805		1021
806	# if the expression is sensitive to external events, prepare reevaluation then	1022	# if the expression is sensitive to external events, prepare reevaluation then
807		1023	$self->compile_frame ($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	$self->disable ("rootpmap_change");
840	}
841		1024
842	# clear stuff we no longer need	1025	# clear stuff we no longer need
843		1026
844	%$old = ();	1027	# unless (%{ $frame->[FR_STATE] }) {
845
846	unless ($repeat) {
847	delete $self->{state};	1028	# delete $self->{state};
848	delete $self->{expr};	1029	# delete $self->{expr};
849	}	1030	# }
850		1031
851	# set background pixmap	1032	# set background pixmap
852		1033
853	$self->set_background ($img, $self->{border});	1034	$self->set_background ($img, $self->{border});
854	$self->scr_recolour (0);	1035	$self->scr_recolour (0);

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.48 by root, Sun Jun 10 15:01:14 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 1.48 by root, Sun Jun 10 15:01:14 2012 UTC vs.
Revision 1.69 by root, Mon Jul 2 01:32:26 2012 UTC