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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.49 by root, Sun Jun 10 15:29:18 2012 UTC vs.
Revision 1.64 by root, Tue Jun 19 20:49:53 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 expression is evaluated once per hour. It will set F<sunday.png> as
79	background on Sundays, and F<weekday.png> on all other days.	79	background on Sundays, and F<weekday.png> on all other days.
80		80
81	Fortunately, we expect that most expressions will be much simpler, with	81	Fortunately, we expect that most expressions will be much simpler, with
82	little Perl knowledge needed.	82	little Perl knowledge needed.
83		83
…		…
117	horizontal and vertical dimensions. For example, this halves the image	117	horizontal and vertical dimensions. For example, this halves the image
118	width and doubles the image height:	118	width and doubles the image height:
119		119
120	scale 0.5, 2, load "$HOME/mypic.png"	120	scale 0.5, 2, load "$HOME/mypic.png"
121		121
122	Other effects than scalign are also readily available, for exmaple, you can	122	IF you try out these expressions, you might suffer from sluggishness,
123	tile the image to fill the whole window, instead of resizing it:	123	because each time the terminal is resized, it again loads the PNG image
		124	and scales it. Scaling is usually fats, but loading the image can be quite
		125	time consuming. This is where C<keep> comes in handy:
124		126
		127	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		128
		129	The C<keep> operator executes all the statements inside the braces only
		130	once, or when it thinks the outcome might change. In other cases it
		131	returns the last value computed by the brace block.
		132
		133	This means that the C<load> is only executed once, which makes it much
		134	faster, but alos means that more memory is being used, because the loaded
		135	image must be kept in memory at all times. In this expression, the
		136	trade-off is likely worth it.
		137
		138	But back to effects: Other effects than scaling are also readily
		139	available, for example, you can tile the image to fill the whole window,
		140	instead of resizing it:
		141
125	tile load "$HOME/mypic.png"	142	tile keep { load "$HOME/mypic.png" }
126		143
127	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator	144	In fact, images returned by C<load> are in C<tile> mode by default, so the
128	is kind of superfluous.	145	C<tile> operator is kind of superfluous.
129		146
130	Another common effect is to mirror the image, so that the same edges touch:	147	Another common effect is to mirror the image, so that the same edges
		148	touch:
131		149
132	mirror load "$HOME/mypic.png"	150	mirror keep { load "$HOME/mypic.png" }
133		151
134	This is also a typical background expression:	152	Another common background expression is:
135		153
136	rootalign root	154	rootalign root
137		155
138	It first takes a snapshot of the screen background image, and then	156	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	157	moves it to the upper left corner of the screen (as opposed to the upepr
140	pseudo-transparency, as the image seems to be static while the window is	158	left corner of the terminal window)- the result is pseudo-transparency:
141	moved around.	159	the image seems to be static while the window is moved around.
142		160
143	=head2 CYCLES AND CACHING	161	=head2 CACHING AND SENSITIVITY
144		162
145	As has been mentioned before, the expression might be evaluated multiple	163	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	164	caching results can be very important for a smooth operation. Caching can
147	have begun. Many operators cache their results till the next cycle.	165	also be useful to reduce memory usage, though, for example, when an image
		166	is cached by C<load>, it could be shared by multiple terminal windows
		167	running inside urxvtd.
148		168
149	For example, the C<load> operator keeps a copy of the image. If it is	169	=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		170
153	This only works for one cycle though, so as long as you load the same	171	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	172	... }>. The C<keep> operator takes a block of multiple statements enclosed
155	image, it will forget about the first one.	173	by C<{}> and keeps the return value in memory.
156		174
157	This allows you to either speed things up by keeping multiple images in	175	An expression can be "sensitive" to various external events, such as
158	memory, or comserve memory by loading images more often.	176	scaling or moving the window, root backgorund changes and timers. Simply
		177	using an expression (such as C<scale> without parameters) that depend on
		178	certain changing values (called "variables"), or using those variables
		179	directly, will make an expression sensitive to these events - for example,
		180	using C<scale> or C<TW> will make the expression sensitive to the terminal
		181	size, and thus to resizing events.
159		182
160	For example, you can keep two images in memory and use a random one like	183	When such an event happens, C<keep> will automatically trigger a
161	this:	184	reevaluation of the whole expression with the new value of the expression.
162		185
163	my $img1 = load "img1.png";	186	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		187
167	Since both images are "loaded" every time the expression is evaluated,	188	rootalign once { blur 20, root }
168	they are always kept in memory. Contrast this version:
169		189
170	my $path1 = "img1.png";	190	This makes a blurred copy of the root background once, and on subsequent
171	my $path2 = "img2.png";	191	calls, just root-aligns it. Since C<blur> is usually quite slow and
172	load ((0.5 > rand) ? $path1 : $path2)	192	C<rootalign> is quite fast, this trades extra memory (for the cached
		193	blurred pixmap) with speed (blur only needs to be redone when root
		194	changes).
173		195
174	Here, a path is selected randomly, and load is only called for one image,	196	=head3 C<load> caching
175	so keeps only one image in memory. If, on the next evaluation, luck	197
176	decides to use the other path, then it will have to load that image again.	198	The C<load> operator itself does not keep images in memory, but as long as
		199	the image is still in memory, C<load> will use the in-memory image instead
		200	of loading it freshly from disk.
		201
		202	That means that this expression:
		203
		204	keep { load "$HOME/path..." }
		205
		206	Not only caches the image in memory, other terminal instances that try to
		207	C<load> it can reuse that in-memory copy.
177		208
178	=head1 REFERENCE	209	=head1 REFERENCE
179		210
180	=head2 COMMAND LINE SWITCHES	211	=head2 COMMAND LINE SWITCHES
181		212
…		…
193	Specifying this flag changes the behaviour, so that the image only	224	Specifying this flag changes the behaviour, so that the image only
194	replaces the background of the character area.	225	replaces the background of the character area.
195		226
196	=item --background-interval seconds	227	=item --background-interval seconds
197		228
198	Since some operations in the underlying XRender extension can effetively	229	Since some operations in the underlying XRender extension can effectively
199	freeze your X-server for prolonged time, this extension enforces a minimum	230	freeze your X-server for prolonged time, this extension enforces a minimum
200	time between updates, which is normally about 0.1 seconds.	231	time between updates, which is normally about 0.1 seconds.
201		232
202	If you want to do updates more often, you can decrease this safety	233	If you want to do updates more often, you can decrease this safety
203	interval with this switch.	234	interval with this switch.
204		235
205	=back	236	=back
206		237
207	=cut	238	=cut
208		239
209	our %_IMGCACHE;	240	our %_IMG_CACHE;
210	our $HOME;	241	our $HOME;
211	our ($self, $old, $new);	242	our ($self, $frame);
212	our ($x, $y, $w, $h);	243	our ($x, $y, $w, $h);
213		244
214	# enforce at least this interval between updates	245	# enforce at least this interval between updates
215	our $MIN_INTERVAL = 6/59.951;	246	our $MIN_INTERVAL = 6/59.951;
216		247
217	{	248	{
218	package urxvt::bgdsl; # background language	249	package urxvt::bgdsl; # background language
		250
		251	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
		252	sub FR_CACHE () { 1 } # cached values
		253	sub FR_AGAIN () { 2 } # what this expr is sensitive to
		254	sub FR_STATE () { 3 } # watchers etc.
219		255
220	use List::Util qw(min max sum shuffle);	256	use List::Util qw(min max sum shuffle);
221		257
222	=head2 PROVIDERS/GENERATORS	258	=head2 PROVIDERS/GENERATORS
223		259
…		…
230	=item load $path	266	=item load $path
231		267
232	Loads the image at the given C<$path>. The image is set to plane tiling	268	Loads the image at the given C<$path>. The image is set to plane tiling
233	mode.	269	mode.
234		270
235	Loaded images will be cached for one cycle.	271	If the image is already in memory (e.g. because another temrinal instance
		272	uses it), then the in-memory copy us returned instead.
236		273
		274	=item load_uc $path
		275
		276	Load uncached - same as load, but does not cache the image, which means it
		277	is I<always> loaded from the filesystem again.
		278
237	=cut	279	=cut
		280
		281	sub load_uc($) {
		282	$self->new_img_from_file ($path)
		283	}
238		284
239	sub load($) {	285	sub load($) {
240	my ($path) = @_;	286	my ($path) = @_;
241		287
242	$new->{load}{$path} = $old->{load}{$path} \|\| $self->new_img_from_file ($path);	288	$_IMG_CACHE{$path} \|\| do {
		289	my $img = load_uc $path;
		290	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		291	$img
		292	}
243	}	293	}
244		294
245	=item root	295	=item root
246		296
247	Returns the root window pixmap, that is, hopefully, the background image	297	Returns the root window pixmap, that is, hopefully, the background image
248	of your screen. The image is set to extend mode.	298	of your screen.
249		299
250	This function makes your expression root sensitive, that means it will be	300	This function makes your expression root sensitive, that means it will be
251	reevaluated when the bg image changes.	301	reevaluated when the bg image changes.
252		302
253	=cut	303	=cut
254		304
255	sub root() {	305	sub root() {
256	$new->{rootpmap_sensitive} = 1;	306	$frame->[FR_AGAIN]{rootpmap} = 1;
257	die "root op not supported, exg, we need you";	307	$self->new_img_from_root
258	}	308	}
259		309
260	=item solid $colour	310	=item solid $colour
261		311
262	=item solid $width, $height, $colour	312	=item solid $width, $height, $colour
…		…
270	=cut	320	=cut
271		321
272	sub solid($;$$) {	322	sub solid($;$$) {
273	my $colour = pop;	323	my $colour = pop;
274		324
275	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	325	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
276	$img->fill ($colour);	326	$img->fill ($colour);
277	$img	327	$img
278	}	328	}
279		329
280	=item clone $img	330	=item clone $img
…		…
286		336
287	sub clone($) {	337	sub clone($) {
288	$_[0]->clone	338	$_[0]->clone
289	}	339	}
290		340
291	=back	341	=item merge $img ...
		342
		343	Takes any number of images and merges them together, creating a single
		344	image containing them all. The tiling mode of the first image is used as
		345	the tiling mdoe of the resulting image.
		346
		347	This function is called automatically when an expression returns multiple
		348	images.
		349
		350	=cut
		351
		352	sub merge(@) {
		353	return $_[0] unless $#_;
		354
		355	# rather annoyingly clumsy, but optimisation is for another time
		356
		357	my $x0 = +1e9;
		358	my $y0 = +1e9;
		359	my $x1 = -1e9;
		360	my $y1 = -1e9;
		361
		362	for (@_) {
		363	my ($x, $y, $w, $h) = $_->geometry;
		364
		365	$x0 = $x if $x0 > $x;
		366	$y0 = $y if $y0 > $y;
		367
		368	$x += $w;
		369	$y += $h;
		370
		371	$x1 = $x if $x1 < $x;
		372	$y1 = $y if $y1 < $y;
		373	}
		374
		375	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		376	$base->repeat_mode ($_[0]->repeat_mode);
		377	$base->fill ([0, 0, 0, 0]);
		378
		379	$base->draw ($_)
		380	for @_;
		381
		382	$base
		383	}
292		384
293	=head2 TILING MODES	385	=head2 TILING MODES
294		386
295	The following operators modify the tiling mode of an image, that is, the	387	The following operators modify the tiling mode of an image, that is, the
296	way that pixels outside the image area are painted when the image is used.	388	way that pixels outside the image area are painted when the image is used.
…		…
326	become transparent. This mode is most useful when you want to place an	418	become transparent. This mode is most useful when you want to place an
327	image over another image or the background colour while leaving all	419	image over another image or the background colour while leaving all
328	background pixels outside the image unchanged.	420	background pixels outside the image unchanged.
329		421
330	Example: load an image and display it in the upper left corner. The rest	422	Example: load an image and display it in the upper left corner. The rest
331	of the space is left "empty" (transparent or wahtever your compisotr does	423	of the space is left "empty" (transparent or whatever your compositor does
332	in alpha mode, else background colour).	424	in alpha mode, else background colour).
333		425
334	pad load "mybg.png"	426	pad load "mybg.png"
335		427
336	=item extend $img	428	=item extend $img
337		429
338	Extends the image over the whole plane, using the closest pixel in the	430	Extends the image over the whole plane, using the closest pixel in the
339	area outside the image. This mode is mostly useful when you more complex	431	area outside the image. This mode is mostly useful when you use more complex
340	filtering operations and want the pixels outside the image to have the	432	filtering operations and want the pixels outside the image to have the
341	same values as the pixels near the edge.	433	same values as the pixels near the edge.
342		434
343	Example: just for curiosity, how does this pixel extension stuff work?	435	Example: just for curiosity, how does this pixel extension stuff work?
344		436
…		…
393	Using these functions make your expression sensitive to window moves.	485	Using these functions make your expression sensitive to window moves.
394		486
395	These functions are mainly useful to align images to the root window.	487	These functions are mainly useful to align images to the root window.
396		488
397	Example: load an image and align it so it looks as if anchored to the	489	Example: load an image and align it so it looks as if anchored to the
398	background.	490	background (that's exactly what C<rootalign> does btw.):
399		491
400	move -TX, -TY, load "mybg.png"	492	move -TX, -TY, keep { load "mybg.png" }
401		493
402	=item TW	494	=item TW
403		495
404	Return the width (C<TW>) and height (C<TH>) of the terminal window (the	496	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
405	terminal window is the full window by default, and the character area only	497	terminal window is the full window by default, and the character area only
…		…
411	the window size to conserve memory.	503	the window size to conserve memory.
412		504
413	Example: take the screen background, clip it to the window size, blur it a	505	Example: take the screen background, clip it to the window size, blur it a
414	bit, align it to the window position and use it as background.	506	bit, align it to the window position and use it as background.
415		507
416	clip move -TX, -TY, blur 5, root	508	clip move -TX, -TY, keep { blur 5, root }
417		509
418	=cut	510	=cut
419		511
420	sub TX() { $new->{position_sensitive} = 1; $x }	512	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
421	sub TY() { $new->{position_sensitive} = 1; $y }	513	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
422	sub TW() { $new->{size_sensitive} = 1; $w }	514	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
423	sub TH() { $new->{size_sensitive} = 1; $h }	515	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
424		516
425	=item now	517	=item now
426		518
427	Returns the current time as (fractional) seconds since the epoch.	519	Returns the current time as (fractional) seconds since the epoch.
428		520
…		…
435	C<$seconds> seconds.	527	C<$seconds> seconds.
436		528
437	Example: load some image and rotate it according to the time of day (as if it were	529	Example: load some image and rotate it according to the time of day (as if it were
438	the hour pointer of a clock). Update this image every minute.	530	the hour pointer of a clock). Update this image every minute.
439		531
		532	again 60;
440	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"	533	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
441		534
442	=item counter $seconds	535	=item counter $seconds
443		536
444	Like C<again>, but also returns an increasing counter value, starting at	537	Like C<again>, but also returns an increasing counter value, starting at
445	0, which might be useful for some simple animation effects.	538	0, which might be useful for some simple animation effects.
…		…
447	=cut	540	=cut
448		541
449	sub now() { urxvt::NOW }	542	sub now() { urxvt::NOW }
450		543
451	sub again($) {	544	sub again($) {
452	$new->{again} = $_[0];	545	$frame->[FR_AGAIN]{time} = $_[0];
453	}	546	}
454		547
455	sub counter($) {	548	sub counter($) {
456	$new->{again} = $_[0];	549	$frame->[FR_AGAIN]{time} = $_[0];
457	$self->{counter} + 0	550	$frame->[FR_STATE]{counter} + 0
458	}	551	}
459		552
460	=back	553	=back
461		554
462	=head2 SHAPE CHANGING OPERATORS	555	=head2 SHAPE CHANGING OPERATORS
…		…
482	assumed.	575	assumed.
483		576
484	Example: load an image, blur it, and clip it to the window size to save	577	Example: load an image, blur it, and clip it to the window size to save
485	memory.	578	memory.
486		579
487	clip blur 10, load "mybg.png"	580	clip keep { blur 10, load "mybg.png" }
488		581
489	=cut	582	=cut
490		583
491	sub clip($;$$;$$) {	584	sub clip($;$$;$$) {
492	my $img = pop;	585	my $img = pop;
…		…
586	the terminal window (or the box specified by C<$width> and C<$height> if	679	the terminal window (or the box specified by C<$width> and C<$height> if
587	given).	680	given).
588		681
589	Example: load an image and center it.	682	Example: load an image and center it.
590		683
591	center pad load "mybg.png"	684	center keep { pad load "mybg.png" }
592		685
593	=item rootalign $img	686	=item rootalign $img
594		687
595	Moves the image so that it appears glued to the screen as opposed to the	688	Moves the image so that it appears glued to the screen as opposed to the
596	window. This gives the illusion of a larger area behind the window. It is	689	window. This gives the illusion of a larger area behind the window. It is
597	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	690	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
598	top left of the screen.	691	top left of the screen.
599		692
600	Example: load a background image, put it in mirror mode and root align it.	693	Example: load a background image, put it in mirror mode and root align it.
601		694
602	rootalign mirror load "mybg.png"	695	rootalign keep { mirror load "mybg.png" }
603		696
604	Example: take the screen background and align it, giving the illusion of	697	Example: take the screen background and align it, giving the illusion of
605	transparency as long as the window isn't in front of other windows.	698	transparency as long as the window isn't in front of other windows.
606		699
607	rootalign root	700	rootalign root
…		…
632		725
633	sub rootalign($) {	726	sub rootalign($) {
634	move -TX, -TY, $_[0]	727	move -TX, -TY, $_[0]
635	}	728	}
636		729
		730	=item rotate $center_x, $center_y, $degrees, $img
		731
		732	Rotates the image clockwise by C<$degrees> degrees, around the point at
		733	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		734
		735	Example: rotate the image by 90 degrees around it's center.
		736
		737	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		738
		739	=cut
		740
		741	sub rotate($$$$) {
		742	my $img = pop;
		743	$img->rotate (
		744	$_[0] * ($img->w + $img->x),
		745	$_[1] * ($img->h + $img->y),
		746	$_[2] * (3.14159265 / 180),
		747	)
		748	}
		749
637	=back	750	=back
638		751
639	=head2 COLOUR MODIFICATIONS	752	=head2 COLOUR MODIFICATIONS
640		753
641	The following operators change the pixels of the image.	754	The following operators change the pixels of the image.
…		…
675		788
676	Values less than 0 reduce brightness, while values larger than 0 increase	789	Values less than 0 reduce brightness, while values larger than 0 increase
677	it. Useful range is from -1 to 1 - the former results in a black, the	790	it. Useful range is from -1 to 1 - the former results in a black, the
678	latter in a white picture.	791	latter in a white picture.
679		792
680	Due to idiosynchrasies in the underlying XRender extension, biases less	793	Due to idiosyncrasies in the underlying XRender extension, biases less
681	than zero can be I<very> slow.	794	than zero can be I<very> slow.
682		795
683	=cut	796	=cut
684		797
685	sub contrast($$;$$;$) {	798	sub contrast($$;$$;$) {
…		…
723	sub blur($$;$) {	836	sub blur($$;$) {
724	my $img = pop;	837	my $img = pop;
725	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	838	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
726	}	839	}
727		840
728	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
729
730	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
731	pointer at C<$center_x> and C<$center_y> (specified as factor of image
732	width/height), generating a new image with width C<$new_width> and height
733	C<$new_height>.
734
735	#TODO# new width, height, maybe more operators?
736
737	Example: rotate the image by 90 degrees
738
739	=cut
740
741	sub rotate($$$$$$) {
742	my $img = pop;
743	$img->rotate (
744	$_[0],
745	$_[1],
746	$_[2] * $img->w,
747	$_[3] * $img->h,
748	$_[4] * (3.14159265 / 180),
749	)
750	}
751
752	=back	841	=back
753		842
		843	=head2 OTHER STUFF
		844
		845	Anything that didn't fit any of the other categories, even after applying
		846	force and closing our eyes.
		847
		848	=over 4
		849
		850	=item once { ... }
		851
		852	This function takes a code block as argument, that is, one or more
		853	statements enclosed by braces.
		854
		855	The trick is that this code block is only evaluated once - future calls
		856	will simply return the original image (yes, it should only be used with
		857	images).
		858
		859	This can be extremely useful to avoid redoing the same slow operations
		860	again and again- for example, if your background expression takes the root
		861	background, blurs it and then root-aligns it it would have to blur the
		862	root background on every window move or resize.
		863
		864	In fact, urxvt itself encloses the whole expression in some kind of
		865	C<once> block so it only is reevaluated as required.
		866
		867	Putting the blur into a C<once> block will make sure the blur is only done
		868	once:
		869
		870	rootlign once { blur 10, root }
		871
		872	This leaves the question of how to force reevaluation of the block,
		873	in case the root background changes: If expression inside the block
		874	is sensitive to some event (root background changes, window geometry
		875	changes), then it will be reevaluated automatically as needed.
		876
		877	=item once_again
		878
		879	Resets all C<once> block as if they had never been called, i.e. on the
		880	next call they will be reevaluated again.
		881
		882	=cut
		883
		884	sub once(&) {
		885	my $id = $_[0]+0;
		886
		887	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		888
		889	unless ($frame->[FR_CACHE]) {
		890	$frame->[FR_CACHE] = [ $_[0]() ];
		891
		892	my $self = $self;
		893	my $frame = $frame;
		894	Scalar::Util::weaken $frame;
		895	$self->compile_frame ($frame, sub {
		896	# clear this frame cache, also for all parents
		897	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		898	undef $frame->[FR_CACHE];
		899	}
		900
		901	$self->recalculate;
		902	});
		903	};
		904
		905	# in scalar context we always return the first original result, which
		906	# is not quite how perl works.
		907	wantarray
		908	? @{ $frame->[FR_CACHE] }
		909	: $frame->[FR_CACHE][0]
		910	}
		911
		912	sub once_again() {
		913	delete $self->{frame_cache};
		914	}
		915
		916	=back
		917
754	=cut	918	=cut
755		919
756	}	920	}
757		921
758	sub parse_expr {	922	sub parse_expr {
759	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	923	my $expr = eval
		924	"sub {\n"
		925	. "package urxvt::bgdsl;\n"
		926	. "#line 0 'background expression'\n"
		927	. "$_[0]\n"
		928	. "}";
760	die if $@;	929	die if $@;
761	$expr	930	$expr
762	}	931	}
763		932
764	# compiles a parsed expression	933	# compiles a parsed expression
765	sub set_expr {	934	sub set_expr {
766	my ($self, $expr) = @_;	935	my ($self, $expr) = @_;
767		936
		937	$self->{root} = [];
768	$self->{expr} = $expr;	938	$self->{expr} = $expr;
769	$self->recalculate;	939	$self->recalculate;
		940	}
		941
		942	# takes a hash of sensitivity indicators and installs watchers
		943	sub compile_frame {
		944	my ($self, $frame, $cb) = @_;
		945
		946	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		947	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		948
		949	# don't keep stuff alive
		950	Scalar::Util::weaken $state;
		951
		952	if ($again->{nested}) {
		953	$state->{nested} = 1;
		954	} else {
		955	delete $state->{nested};
		956	}
		957
		958	if (my $interval = $again->{time}) {
		959	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		960	if $state->{time}[0] != $interval;
		961
		962	# callback might have changed, although we could just rule that out
		963	$state->{time}[1]->cb (sub {
		964	++$state->{counter};
		965	$cb->();
		966	});
		967	} else {
		968	delete $state->{time};
		969	}
		970
		971	if ($again->{position}) {
		972	$state->{position} = $self->on (position_change => $cb);
		973	} else {
		974	delete $state->{position};
		975	}
		976
		977	if ($again->{size}) {
		978	$state->{size} = $self->on (size_change => $cb);
		979	} else {
		980	delete $state->{size};
		981	}
		982
		983	if ($again->{rootpmap}) {
		984	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		985	} else {
		986	delete $state->{rootpmap};
		987	}
770	}	988	}
771		989
772	# evaluate the current bg expression	990	# evaluate the current bg expression
773	sub recalculate {	991	sub recalculate {
774	my ($arg_self) = @_;	992	my ($arg_self) = @_;
…		…
784		1002
785	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1003	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
786		1004
787	# set environment to evaluate user expression	1005	# set environment to evaluate user expression
788		1006
789	local $self = $arg_self;	1007	local $self = $arg_self;
790
791	local $HOME = $ENV{HOME};	1008	local $HOME = $ENV{HOME};
792	local $old = $self->{state};	1009	local $frame = [];
793	local $new = my $state = $self->{state} = {};
794		1010
795	($x, $y, $w, $h) =
796	$self->background_geometry ($self->{border});	1011	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
797		1012
798	# evaluate user expression	1013	# evaluate user expression
799		1014
800	my $img = eval { $self->{expr}->() };	1015	my @img = eval { $self->{expr}->() };
801	warn $@ if $@;#d#	1016	die $@ if $@;
802	die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";	1017	die "background-expr did not return anything.\n" unless @img;
		1018	die "background-expr: expected image(s), got something else.\n"
		1019	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
803		1020
804	$state->{size_sensitive} = 1	1021	my $img = urxvt::bgdsl::merge @img;
		1022
		1023	$frame->[FR_AGAIN]{size} = 1
805	if $img->repeat_mode != urxvt::RepeatNormal;	1024	if $img->repeat_mode != urxvt::RepeatNormal;
806		1025
807	# if the expression is sensitive to external events, prepare reevaluation then	1026	# if the expression is sensitive to external events, prepare reevaluation then
808		1027	$self->compile_frame ($frame, sub { $arg_self->recalculate });
809	my $repeat;
810
811	if (my $again = $state->{again}) {
812	$repeat = 1;
813	my $self = $self;
814	$state->{timer} = $again == $old->{again}
815	? $old->{timer}
816	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
817	++$self->{counter};
818	$self->recalculate
819	});
820	}
821
822	if (delete $state->{position_sensitive}) {
823	$repeat = 1;
824	$self->enable (position_change => sub { $_[0]->recalculate });
825	} else {
826	$self->disable ("position_change");
827	}
828
829	if (delete $state->{size_sensitive}) {
830	$repeat = 1;
831	$self->enable (size_change => sub { $_[0]->recalculate });
832	} else {
833	$self->disable ("size_change");
834	}
835
836	if (delete $state->{rootpmap_sensitive}) {
837	$repeat = 1;
838	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
839	} else {
840	$self->disable ("rootpmap_change");
841	}
842		1028
843	# clear stuff we no longer need	1029	# clear stuff we no longer need
844		1030
845	%$old = ();	1031	# unless (%{ $frame->[FR_STATE] }) {
846
847	unless ($repeat) {
848	delete $self->{state};	1032	# delete $self->{state};
849	delete $self->{expr};	1033	# delete $self->{expr};
850	}	1034	# }
851		1035
852	# set background pixmap	1036	# set background pixmap
853		1037
854	$self->set_background ($img, $self->{border});	1038	$self->set_background ($img, $self->{border});
855	$self->scr_recolour (0);	1039	$self->scr_recolour (0);

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.49 by root, Sun Jun 10 15:29:18 2012 UTC vs. Revision 1.64 by root, Tue Jun 19 20:49:53 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.49 by root, Sun Jun 10 15:29:18 2012 UTC vs.
Revision 1.64 by root, Tue Jun 19 20:49:53 2012 UTC