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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.45 by root, Sun Jun 10 11:53:32 2012 UTC vs.
Revision 1.69 by root, Mon Jul 2 01:32:26 2012 UTC

…		…
1	#! perl	1	#! perl
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		5	#:META:X_RESOURCE:%.interval:seconds:minimum time between updates
6	#TODO: once, rootalign
7		6
8	=head1 NAME	7	=head1 NAME
9		8
10	background - manage terminal background	9	background - manage terminal background
11		10
12	=head1 SYNOPSIS	11	=head1 SYNOPSIS
13		12
14	urxvt --background-expr 'background expression'	13	urxvt --background-expr 'background expression'
15	--background-border	14	--background-border
		15	--background-interval seconds
16		16
17	=head1 DESCRIPTION	17	=head1 DESCRIPTION
18		18
19	This extension manages the terminal background by creating a picture that	19	This extension manages the terminal background by creating a picture that
20	is behind the text, replacing the normal background colour.	20	is behind the text, replacing the normal background colour.
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 it's size changes.	62	after its size changes.
63		63
64	=head2 EXPRESSIONS	64	=head2 EXPRESSIONS
65		65
66	Expressions are normal Perl expressions, in fact, they are Perl blocks -	66	Expressions are normal Perl expressions, in fact, they are Perl blocks -
67	which means you could use multiple lines and statements:	67	which means you could use multiple lines and statements:
68		68
		69	scale keep {
69	again 3600;	70	again 3600;
70	if (localtime now)[6]) {	71	if (localtime now)[6]) {
71	return scale load "$HOME/weekday.png";	72	return load "$HOME/weekday.png";
72	} else {	73	} else {
73	return scale load "$HOME/sunday.png";	74	return load "$HOME/sunday.png";
		75	}
74	}	76	}
75		77
76	This expression gets evaluated once per hour. It will set F<sunday.png> as	78	This inner expression is evaluated once per hour (and whenever the
		79	temrinal window is resized). It sets F<sunday.png> as background on
77	background on Sundays, and F<weekday.png> on all other days.	80	Sundays, and F<weekday.png> on all other days.
78		81
79	Fortunately, we expect that most expressions will be much simpler, with	82	Fortunately, we expect that most expressions will be much simpler, with
80	little Perl knowledge needed.	83	little Perl knowledge needed.
81		84
82	Basically, you always start with a function that "generates" an image	85	Basically, you always start with a function that "generates" an image
…		…
115	horizontal and vertical dimensions. For example, this halves the image	118	horizontal and vertical dimensions. For example, this halves the image
116	width and doubles the image height:	119	width and doubles the image height:
117		120
118	scale 0.5, 2, load "$HOME/mypic.png"	121	scale 0.5, 2, load "$HOME/mypic.png"
119		122
120	Other effects than scalign are also readily available, for exmaple, you can	123	IF you try out these expressions, you might suffer from some sluggishness,
121	tile the image to fill the whole window, instead of resizing it:	124	because each time the terminal is resized, it loads the PNG image agin
		125	and scales it. Scaling is usually fast (and unavoidable), but loading the
		126	image can be quite time consuming. This is where C<keep> comes in handy:
122		127
		128	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		129
		130	The C<keep> operator executes all the statements inside the braces only
		131	once, or when it thinks the outcome might change. In other cases it
		132	returns the last value computed by the brace block.
		133
		134	This means that the C<load> is only executed once, which makes it much
		135	faster, but also means that more memory is being used, because the loaded
		136	image must be kept in memory at all times. In this expression, the
		137	trade-off is likely worth it.
		138
		139	But back to effects: Other effects than scaling are also readily
		140	available, for example, you can tile the image to fill the whole window,
		141	instead of resizing it:
		142
123	tile load "$HOME/mypic.png"	143	tile keep { load "$HOME/mypic.png" }
124		144
125	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator	145	In fact, images returned by C<load> are in C<tile> mode by default, so the
126	is kind of superfluous.	146	C<tile> operator is kind of superfluous.
127		147
128	Another common effect is to mirror the image, so that the same edges touch:	148	Another common effect is to mirror the image, so that the same edges
		149	touch:
129		150
130	mirror load "$HOME/mypic.png"	151	mirror keep { load "$HOME/mypic.png" }
131		152
132	This is also a typical background expression:	153	Another common background expression is:
133		154
134	rootalign root	155	rootalign root
135		156
136	It first takes a snapshot of the screen background image, and then	157	This one first takes a snapshot of the screen background image, and then
137	moves it to the upper left corner of the screen - the result is	158	moves it to the upper left corner of the screen (as opposed to the upper
138	pseudo-transparency, as the image seems to be static while the window is	159	left corner of the terminal window)- the result is pseudo-transparency:
139	moved around.	160	the image seems to be static while the window is moved around.
140		161
141	=head2 CYCLES AND CACHING	162	=head2 CACHING AND SENSITIVITY
142		163
143	As has been mentioned before, the expression might be evaluated multiple	164	Since some operations (such as C<load> and C<blur>) can take a long time,
144	times. Each time the expression is reevaluated, a new cycle is said to	165	caching results can be very important for a smooth operation. Caching can
145	have begun. Many operators cache their results till the next cycle.	166	also be useful to reduce memory usage, though, for example, when an image
		167	is cached by C<load>, it could be shared by multiple terminal windows
		168	running inside urxvtd.
146		169
147	For example, the C<load> operator keeps a copy of the image. If it is	170	=head3 C<keep { ... }> caching
148	asked to load the same image on the next cycle it will not load it again,
149	but return the cached copy.
150		171
151	This only works for one cycle though, so as long as you load the same	172	The most important way to cache expensive operations is to use C<keep {
152	image every time, it will always be cached, but when you load a different	173	... }>. The C<keep> operator takes a block of multiple statements enclosed
153	image, it will forget about the first one.	174	by C<{}> and keeps the return value in memory.
154		175
155	This allows you to either speed things up by keeping multiple images in	176	An expression can be "sensitive" to various external events, such as
156	memory, or 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.
157		183
158	For example, you can keep two images in memory and use a random one like	184	When such an event happens, C<keep> will automatically trigger a
159	this:	185	reevaluation of the whole expression with the new value of the expression.
160		186
161	my $img1 = load "img1.png";	187	C<keep> is most useful for expensive operations, such as C<blur>:
162	my $img2 = load "img2.png";
163	(0.5 > rand) ? $img1 : $img2
164		188
165	Since both images are "loaded" every time the expression is evaluated,	189	rootalign keep { blur 20, root }
166	they are always kept in memory. Contrast this version:
167		190
168	my $path1 = "img1.png";	191	This makes a blurred copy of the root background once, and on subsequent
169	my $path2 = "img2.png";	192	calls, just root-aligns it. Since C<blur> is usually quite slow and
170	load ((0.5 > rand) ? $path1 : $path2)	193	C<rootalign> is quite fast, this trades extra memory (for the cached
		194	blurred pixmap) with speed (blur only needs to be redone when root
		195	changes).
171		196
172	Here, a path is selected randomly, and load is only called for one image,	197	=head3 C<load> caching
173	so keeps only one image in memory. If, on the next evaluation, luck	198
174	decides to use the other path, then it will have to load that image again.	199	The C<load> operator itself does not keep images in memory, but as long as
		200	the image is still in memory, C<load> will use the in-memory image instead
		201	of loading it freshly from disk.
		202
		203	That means that this expression:
		204
		205	keep { load "$HOME/path..." }
		206
		207	Not only caches the image in memory, other terminal instances that try to
		208	C<load> it can reuse that in-memory copy.
175		209
176	=head1 REFERENCE	210	=head1 REFERENCE
177		211
178	=head2 COMMAND LINE SWITCHES	212	=head2 COMMAND LINE SWITCHES
179		213
…		…
189	overwriting borders and any other areas, such as the scrollbar.	223	overwriting borders and any other areas, such as the scrollbar.
190		224
191	Specifying this flag changes the behaviour, so that the image only	225	Specifying this flag changes the behaviour, so that the image only
192	replaces the background of the character area.	226	replaces the background of the character area.
193		227
		228	=item --background-interval seconds
		229
		230	Since some operations in the underlying XRender extension can effectively
		231	freeze your X-server for prolonged time, this extension enforces a minimum
		232	time between updates, which is normally about 0.1 seconds.
		233
		234	If you want to do updates more often, you can decrease this safety
		235	interval with this switch.
		236
194	=back	237	=back
195		238
196	=cut	239	=cut
197		240
		241	our %_IMG_CACHE;
198	our $HOME;	242	our $HOME;
199	our ($self, $old, $new);	243	our ($self, $frame);
200	our ($x, $y, $w, $h);	244	our ($x, $y, $w, $h);
201		245
202	# enforce at least this interval between updates	246	# enforce at least this interval between updates
203	our $MIN_INTERVAL = 1/100;	247	our $MIN_INTERVAL = 6/59.951;
204		248
205	{	249	{
206	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.
207		256
208	use List::Util qw(min max sum shuffle);	257	use List::Util qw(min max sum shuffle);
209		258
210	=head2 PROVIDERS/GENERATORS	259	=head2 PROVIDERS/GENERATORS
211		260
…		…
218	=item load $path	267	=item load $path
219		268
220	Loads the image at the given C<$path>. The image is set to plane tiling	269	Loads the image at the given C<$path>. The image is set to plane tiling
221	mode.	270	mode.
222		271
223	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 $path
		276
		277	Load uncached - same as load, but does not cache the image, which means it
		278	is I<always> loaded from the filesystem again.
224		279
225	=cut	280	=cut
226		281
227	sub load($) {	282	sub load($) {
228	my ($path) = @_;	283	my ($path) = @_;
229		284
230	$new->{load}{$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	}
231	}	290	}
232		291
233	=item root	292	=item root
234		293
235	Returns the root window pixmap, that is, hopefully, the background image	294	Returns the root window pixmap, that is, hopefully, the background image
236	of your screen. The image is set to extend mode.	295	of your screen.
237		296
238	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
239	reevaluated when the bg image changes.	298	reevaluated when the bg image changes.
240		299
241	=cut	300	=cut
242		301
243	sub root() {	302	sub root() {
244	$new->{rootpmap_sensitive} = 1;	303	$frame->[FR_AGAIN]{rootpmap} = 1;
245	die "root op not supported, exg, we need you";	304	$self->new_img_from_root
246	}	305	}
247		306
248	=item solid $colour	307	=item solid $colour
249		308
250	=item solid $width, $height, $colour	309	=item solid $width, $height, $colour
…		…
258	=cut	317	=cut
259		318
260	sub solid($;$$) {	319	sub solid($;$$) {
261	my $colour = pop;	320	my $colour = pop;
262		321
263	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);
264	$img->fill ($colour);	323	$img->fill ($colour);
265	$img	324	$img
266	}	325	}
267		326
268	=item clone $img	327	=item clone $img
…		…
274		333
275	sub clone($) {	334	sub clone($) {
276	$_[0]->clone	335	$_[0]->clone
277	}	336	}
278		337
279	=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	}
280		381
281	=head2 TILING MODES	382	=head2 TILING MODES
282		383
283	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
284	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.
…		…
314	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
315	image over another image or the background colour while leaving all	416	image over another image or the background colour while leaving all
316	background pixels outside the image unchanged.	417	background pixels outside the image unchanged.
317		418
318	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
319	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
320	in alpha mode, else background colour).	421	in alpha mode, else background colour).
321		422
322	pad load "mybg.png"	423	pad load "mybg.png"
323		424
324	=item extend $img	425	=item extend $img
325		426
326	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
327	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
328	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
329	same values as the pixels near the edge.	430	same values as the pixels near the edge.
330		431
331	Example: just for curiosity, how does this pixel extension stuff work?	432	Example: just for curiosity, how does this pixel extension stuff work?
332		433
…		…
381	Using these functions make your expression sensitive to window moves.	482	Using these functions make your expression sensitive to window moves.
382		483
383	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.
384		485
385	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
386	background.	487	background (that's exactly what C<rootalign> does btw.):
387		488
388	move -TX, -TY, load "mybg.png"	489	move -TX, -TY, keep { load "mybg.png" }
389		490
390	=item TW	491	=item TW
391		492
392	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
393	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
…		…
399	the window size to conserve memory.	500	the window size to conserve memory.
400		501
401	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
402	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.
403		504
404	clip move -TX, -TY, blur 5, root	505	clip move -TX, -TY, keep { blur 5, root }
405		506
406	=cut	507	=cut
407		508
408	sub TX() { $new->{position_sensitive} = 1; $x }	509	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
409	sub TY() { $new->{position_sensitive} = 1; $y }	510	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
410	sub TW() { $new->{size_sensitive} = 1; $w }	511	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
411	sub TH() { $new->{size_sensitive} = 1; $h }	512	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
412		513
413	=item now	514	=item now
414		515
415	Returns the current time as (fractional) seconds since the epoch.	516	Returns the current time as (fractional) seconds since the epoch.
416		517
…		…
423	C<$seconds> seconds.	524	C<$seconds> seconds.
424		525
425	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
426	the hour pointer of a clock). Update this image every minute.	527	the hour pointer of a clock). Update this image every minute.
427		528
		529	again 60;
428	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" }
429		531
430	=item counter $seconds	532	=item counter $seconds
431		533
432	Like C<again>, but also returns an increasing counter value, starting at	534	Like C<again>, but also returns an increasing counter value, starting at
433	0, which might be useful for some simple animation effects.	535	0, which might be useful for some simple animation effects.
…		…
435	=cut	537	=cut
436		538
437	sub now() { urxvt::NOW }	539	sub now() { urxvt::NOW }
438		540
439	sub again($) {	541	sub again($) {
440	$new->{again} = $_[0];	542	$frame->[FR_AGAIN]{time} = $_[0];
441	}	543	}
442		544
443	sub counter($) {	545	sub counter($) {
444	$new->{again} = $_[0];	546	$frame->[FR_AGAIN]{time} = $_[0];
445	$self->{counter} + 0	547	$frame->[FR_STATE]{counter} + 0
446	}	548	}
447		549
448	=back	550	=back
449		551
450	=head2 SHAPE CHANGING OPERATORS	552	=head2 SHAPE CHANGING OPERATORS
…		…
470	assumed.	572	assumed.
471		573
472	Example: load an image, blur it, and clip it to the window size to save	574	Example: load an image, blur it, and clip it to the window size to save
473	memory.	575	memory.
474		576
475	clip blur 10, load "mybg.png"	577	clip keep { blur 10, load "mybg.png" }
476		578
477	=cut	579	=cut
478		580
479	sub clip($;$$;$$) {	581	sub clip($;$$;$$) {
480	my $img = pop;	582	my $img = pop;
…		…
553		655
554	Example: move the image right by 20 pixels and down by 30.	656	Example: move the image right by 20 pixels and down by 30.
555		657
556	move 20, 30, ...	658	move 20, 30, ...
557		659
		660	=item align $xalign, $yalign, $img
		661
		662	Aligns the image according to a factor - C<0> means the image is moved to
		663	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		664	exactly centered and C<1> means it touches the right or bottom edge.
		665
		666	Example: remove any visible border around an image, center it vertically but move
		667	it to the right hand side.
		668
		669	align 1, 0.5, pad $img
		670
558	=item center $img	671	=item center $img
559		672
560	=item center $width, $height, $img	673	=item center $width, $height, $img
561		674
562	Centers the image, i.e. the center of the image is moved to the center of	675	Centers the image, i.e. the center of the image is moved to the center of
563	the terminal window (or the box specified by C<$width> and C<$height> if	676	the terminal window (or the box specified by C<$width> and C<$height> if
564	given).	677	given).
		678
		679	Example: load an image and center it.
		680
		681	center keep { pad load "mybg.png" }
565		682
566	=item rootalign $img	683	=item rootalign $img
567		684
568	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
569	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
570	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
571	top left of the screen.	688	top left of the screen.
572		689
573	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.
574		691
575	rootalign mirror load "mybg.png"	692	rootalign keep { mirror load "mybg.png" }
576		693
577	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
578	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.
579		696
580	rootalign root	697	rootalign root
581		698
582	=cut	699	=cut
583		700
584	sub move($$;$) {	701	sub move($$;$) {
585	my $img = pop->clone;	702	my $img = pop->clone;
586	$img->move ($_[0], $_[1]);	703	$img->move ($_[0], $_[1]);
587	$img	704	$img
588	}	705	}
589		706
		707	sub align($;$$) {
		708	my $img = pop;
		709
		710	move $_[0] * (TW - $img->w),
		711	$_[1] * (TH - $img->h),
		712	$img
		713	}
		714
590	sub center($;$$) {	715	sub center($;$$) {
591	my $img = pop;	716	my $img = pop;
592	my $w = $_[0] \|\| TW;	717	my $w = $_[0] \|\| TW;
593	my $h = $_[0] \|\| TH;	718	my $h = $_[1] \|\| TH;
594		719
595	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img	720	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
596	}	721	}
597		722
598	sub rootalign($) {	723	sub rootalign($) {
599	move -TX, -TY, $_[0]	724	move -TX, -TY, $_[0]
		725	}
		726
		727	=item rotate $center_x, $center_y, $degrees, $img
		728
		729	Rotates the image clockwise by C<$degrees> degrees, around the point at
		730	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		731
		732	Example: rotate the image by 90 degrees around it's center.
		733
		734	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		735
		736	=cut
		737
		738	sub rotate($$$$) {
		739	my $img = pop;
		740	$img->rotate (
		741	$_[0] * ($img->w + $img->x),
		742	$_[1] * ($img->h + $img->y),
		743	$_[2] * (3.14159265 / 180),
		744	)
600	}	745	}
601		746
602	=back	747	=back
603		748
604	=head2 COLOUR MODIFICATIONS	749	=head2 COLOUR MODIFICATIONS
…		…
640		785
641	Values less than 0 reduce brightness, while values larger than 0 increase	786	Values less than 0 reduce brightness, while values larger than 0 increase
642	it. Useful range is from -1 to 1 - the former results in a black, the	787	it. Useful range is from -1 to 1 - the former results in a black, the
643	latter in a white picture.	788	latter in a white picture.
644		789
645	Due to idiosynchrasies in the underlying XRender extension, biases less	790	Due to idiosyncrasies in the underlying XRender extension, biases less
646	than zero can be I<very> slow.	791	than zero can be I<very> slow.
647		792
648	=cut	793	=cut
649		794
650	sub contrast($$;$$;$) {	795	sub contrast($$;$$;$) {
651	my $img = pop;	796	my $img = pop;
652	my ($r, $g, $b, $a) = @_;	797	my ($r, $g, $b, $a) = @_;
653		798
654	($g, $b) = ($r, $r) if @_ < 4;	799	($g, $b) = ($r, $r) if @_ < 3;
655	$a = 1 if @_ < 5;	800	$a = 1 if @_ < 4;
656		801
657	$img = $img->clone;	802	$img = $img->clone;
658	$img->contrast ($r, $g, $b, $a);	803	$img->contrast ($r, $g, $b, $a);
659	$img	804	$img
660	}	805	}
661		806
662	sub brightness($$;$$;$) {	807	sub brightness($$;$$;$) {
663	my $img = pop;	808	my $img = pop;
664	my ($r, $g, $b, $a) = @_;	809	my ($r, $g, $b, $a) = @_;
665		810
666	($g, $b) = ($r, $r) if @_ < 4;	811	($g, $b) = ($r, $r) if @_ < 3;
667	$a = 1 if @_ < 5;	812	$a = 1 if @_ < 4;
668		813
669	$img = $img->clone;	814	$img = $img->clone;
670	$img->brightness ($r, $g, $b, $a);	815	$img->brightness ($r, $g, $b, $a);
671	$img	816	$img
672	}	817	}
…		…
688	sub blur($$;$) {	833	sub blur($$;$) {
689	my $img = pop;	834	my $img = pop;
690	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	835	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
691	}	836	}
692		837
693	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
694
695	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
696	pointer at C<$center_x> and C<$center_y> (specified as factor of image
697	width/height), generating a new image with width C<$new_width> and height
698	C<$new_height>.
699
700	#TODO# new width, height, maybe more operators?
701
702	Example: rotate the image by 90 degrees
703
704	=cut
705
706	sub rotate($$$$$$) {
707	my $img = pop;
708	$img->rotate (
709	$_[0],
710	$_[1],
711	$_[2] * $img->w,
712	$_[3] * $img->h,
713	$_[4] * (3.14159265 / 180),
714	)
715	}
716
717	=back	838	=back
718		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
719	=cut	914	=cut
720		915
721	}	916	}
722		917
723	sub parse_expr {	918	sub parse_expr {
724	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	. "}";
725	die if $@;	925	die if $@;
726	$expr	926	$expr
727	}	927	}
728		928
729	# compiles a parsed expression	929	# compiles a parsed expression
730	sub set_expr {	930	sub set_expr {
731	my ($self, $expr) = @_;	931	my ($self, $expr) = @_;
732		932
		933	$self->{root} = [];
733	$self->{expr} = $expr;	934	$self->{expr} = $expr;
734	$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 $state->{rootpmap};
		983	}
735	}	984	}
736		985
737	# evaluate the current bg expression	986	# evaluate the current bg expression
738	sub recalculate {	987	sub recalculate {
739	my ($arg_self) = @_;	988	my ($arg_self) = @_;
…		…
749		998
750	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	999	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
751		1000
752	# set environment to evaluate user expression	1001	# set environment to evaluate user expression
753		1002
754	local $self = $arg_self;	1003	local $self = $arg_self;
755
756	local $HOME = $ENV{HOME};	1004	local $HOME = $ENV{HOME};
757	local $old = $self->{state};	1005	local $frame = [];
758	local $new = my $state = $self->{state} = {};
759		1006
760	($x, $y, $w, $h) =
761	$self->background_geometry ($self->{border});	1007	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
762		1008
763	# evaluate user expression	1009	# evaluate user expression
764		1010
765	my $img = eval { $self->{expr}->() };	1011	my @img = eval { $self->{expr}->() };
766	warn $@ if $@;#d#	1012	die $@ if $@;
		1013	die "background-expr did not return anything.\n" unless @img;
		1014	die "background-expr: expected image(s), got something else.\n"
767	die if !UNIVERSAL::isa $img, "urxvt::img";	1015	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
768		1016
769	$state->{size_sensitive} = 1	1017	my $img = urxvt::bgdsl::merge @img;
		1018
		1019	$frame->[FR_AGAIN]{size} = 1
770	if $img->repeat_mode != urxvt::RepeatNormal;	1020	if $img->repeat_mode != urxvt::RepeatNormal;
771		1021
772	# if the expression is sensitive to external events, prepare reevaluation then	1022	# if the expression is sensitive to external events, prepare reevaluation then
773		1023	$self->compile_frame ($frame, sub { $arg_self->recalculate });
774	my $repeat;
775
776	if (my $again = $state->{again}) {
777	$repeat = 1;
778	my $self = $self;
779	$state->{timer} = $again == $old->{again}
780	? $old->{timer}
781	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
782	++$self->{counter};
783	$self->recalculate
784	});
785	}
786
787	if (delete $state->{position_sensitive}) {
788	$repeat = 1;
789	$self->enable (position_change => sub { $_[0]->recalculate });
790	} else {
791	$self->disable ("position_change");
792	}
793
794	if (delete $state->{size_sensitive}) {
795	$repeat = 1;
796	$self->enable (size_change => sub { $_[0]->recalculate });
797	} else {
798	$self->disable ("size_change");
799	}
800
801	if (delete $state->{rootpmap_sensitive}) {
802	$repeat = 1;
803	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
804	} else {
805	$self->disable ("rootpmap_change");
806	}
807		1024
808	# clear stuff we no longer need	1025	# clear stuff we no longer need
809		1026
810	%$old = ();	1027	# unless (%{ $frame->[FR_STATE] }) {
811
812	unless ($repeat) {
813	delete $self->{state};	1028	# delete $self->{state};
814	delete $self->{expr};	1029	# delete $self->{expr};
815	}	1030	# }
816		1031
817	# set background pixmap	1032	# set background pixmap
818		1033
819	$self->set_background ($img, $self->{border});	1034	$self->set_background ($img, $self->{border});
820	$self->scr_recolour (0);	1035	$self->scr_recolour (0);
…		…
822	}	1037	}
823		1038
824	sub on_start {	1039	sub on_start {
825	my ($self) = @_;	1040	my ($self) = @_;
826		1041
827	my $expr = $self->x_resource ("background.expr")	1042	my $expr = $self->x_resource ("%.expr")
828	or return;	1043	or return;
829		1044
		1045	$self->has_render
		1046	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1047
830	$self->set_expr (parse_expr $expr);	1048	$self->set_expr (parse_expr $expr);
831	$self->{border} = $self->x_resource_boolean ("background.border");	1049	$self->{border} = $self->x_resource_boolean ("%.border");
		1050
		1051	$MIN_INTERVAL = $self->x_resource ("%.interval");
832		1052
833	()	1053	()
834	}	1054	}
835		1055

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.45 by root, Sun Jun 10 11:53:32 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 1.45 by root, Sun Jun 10 11:53:32 2012 UTC vs.
Revision 1.69 by root, Mon Jul 2 01:32:26 2012 UTC