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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.50 by root, Sun Jun 10 17:31:53 2012 UTC vs.
Revision 1.70 by root, Mon Jul 2 01:35:37 2012 UTC

…		…
26	to be as simple as possible.	26	to be as simple as possible.
27		27
28	For example, to load an image and scale it to the window size, you would	28	For example, to load an image and scale it to the window size, you would
29	use:	29	use:
30		30
31	urxvt --background-expr 'scale load "/path/to/mybg.png"'	31	urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
32		32
33	Or specified as a X resource:	33	Or specified as a X resource:
34		34
35	URxvt.background-expr: scale load "/path/to/mybg.png"	35	URxvt.background-expr: scale keep { load "/path/to/mybg.png" }
36		36
37	=head1 THEORY OF OPERATION	37	=head1 THEORY OF OPERATION
38		38
39	At startup, just before the window is mapped for the first time, the	39	At startup, just before the window is mapped for the first time, the
40	expression is evaluated and must yield an image. The image is then	40	expression is evaluated and must yield an image. The image is then
…		…
53	If any of the parameters that the expression relies on changes (when the	53	If any of the parameters that the expression relies on changes (when the
54	window is moved or resized, its position or size changes; when the root	54	window is moved or resized, its position or size changes; when the root
55	pixmap is replaced by another one the root background changes; or when the	55	pixmap is replaced by another one the root background changes; or when the
56	timer elapses), then the expression will be evaluated again.	56	timer elapses), then the expression will be evaluated again.
57		57
58	For example, an expression such as C<scale load "$HOME/mybg.png"> scales the	58	For example, an expression such as C<scale keep { load "$HOME/mybg.png"
59	image to the window size, so it relies on the window size and will	59	}> scales the image to the window size, so it relies on the window size
60	be reevaluated each time it is changed, but not when it moves for	60	and will be reevaluated each time it is changed, but not when it moves for
61	example. That ensures that the picture always fills the terminal, even	61	example. That ensures that the picture always fills the terminal, even
62	after 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
…		…
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
194	=item --background-interval seconds	228	=item --background-interval seconds
195		229
196	Since some operations in the underlying XRender extension can effetively	230	Since some operations in the underlying XRender extension can effectively
197	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
198	time between updates, which is normally about 0.1 seconds.	232	time between updates, which is normally about 0.1 seconds.
199		233
200	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
201	interval with this switch.	235	interval with this switch.
202		236
203	=back	237	=back
204		238
205	=cut	239	=cut
206		240
207	our %_IMGCACHE;	241	our %_IMG_CACHE;
208	our $HOME;	242	our $HOME;
209	our ($self, $old, $new);	243	our ($self, $frame);
210	our ($x, $y, $w, $h);	244	our ($x, $y, $w, $h);
211		245
212	# enforce at least this interval between updates	246	# enforce at least this interval between updates
213	our $MIN_INTERVAL = 6/59.951;	247	our $MIN_INTERVAL = 6/59.951;
214		248
215	{	249	{
216	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.
217		256
218	use List::Util qw(min max sum shuffle);	257	use List::Util qw(min max sum shuffle);
219		258
220	=head2 PROVIDERS/GENERATORS	259	=head2 PROVIDERS/GENERATORS
221		260
…		…
228	=item load $path	267	=item load $path
229		268
230	Loads the image at the given C<$path>. The image is set to plane tiling	269	Loads the image at the given C<$path>. The image is set to plane tiling
231	mode.	270	mode.
232		271
233	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 $path
		276
		277	Load uncached - same as load, but does not cache the image, which means it
		278	is I<always> loaded from the filesystem again.
234		279
235	=cut	280	=cut
236		281
237	sub load($) {	282	sub load($) {
238	my ($path) = @_;	283	my ($path) = @_;
239		284
240	$new->{load}{$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	}
241	}	290	}
242		291
243	=item root	292	=item root
244		293
245	Returns the root window pixmap, that is, hopefully, the background image	294	Returns the root window pixmap, that is, hopefully, the background image
246	of your screen. The image is set to extend mode.	295	of your screen.
247		296
248	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
249	reevaluated when the bg image changes.	298	reevaluated when the bg image changes.
250		299
251	=cut	300	=cut
252		301
253	sub root() {	302	sub root() {
254	$new->{rootpmap_sensitive} = 1;	303	$frame->[FR_AGAIN]{rootpmap} = 1;
255	die "root op not supported, exg, we need you";	304	$self->new_img_from_root
256	}	305	}
257		306
258	=item solid $colour	307	=item solid $colour
259		308
260	=item solid $width, $height, $colour	309	=item solid $width, $height, $colour
…		…
268	=cut	317	=cut
269		318
270	sub solid($;$$) {	319	sub solid($;$$) {
271	my $colour = pop;	320	my $colour = pop;
272		321
273	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);
274	$img->fill ($colour);	323	$img->fill ($colour);
275	$img	324	$img
276	}	325	}
277		326
278	=item clone $img	327	=item clone $img
…		…
284		333
285	sub clone($) {	334	sub clone($) {
286	$_[0]->clone	335	$_[0]->clone
287	}	336	}
288		337
289	=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	}
290		381
291	=head2 TILING MODES	382	=head2 TILING MODES
292		383
293	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
294	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.
…		…
324	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
325	image over another image or the background colour while leaving all	416	image over another image or the background colour while leaving all
326	background pixels outside the image unchanged.	417	background pixels outside the image unchanged.
327		418
328	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
329	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
330	in alpha mode, else background colour).	421	in alpha mode, else background colour).
331		422
332	pad load "mybg.png"	423	pad load "mybg.png"
333		424
334	=item extend $img	425	=item extend $img
335		426
336	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
337	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
338	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
339	same values as the pixels near the edge.	430	same values as the pixels near the edge.
340		431
341	Example: just for curiosity, how does this pixel extension stuff work?	432	Example: just for curiosity, how does this pixel extension stuff work?
342		433
…		…
391	Using these functions make your expression sensitive to window moves.	482	Using these functions make your expression sensitive to window moves.
392		483
393	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.
394		485
395	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
396	background.	487	background (that's exactly what C<rootalign> does btw.):
397		488
398	move -TX, -TY, load "mybg.png"	489	move -TX, -TY, keep { load "mybg.png" }
399		490
400	=item TW	491	=item TW
401		492
402	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
403	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
…		…
409	the window size to conserve memory.	500	the window size to conserve memory.
410		501
411	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
412	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.
413		504
414	clip move -TX, -TY, blur 5, root	505	clip move -TX, -TY, keep { blur 5, root }
415		506
416	=cut	507	=cut
417		508
418	sub TX() { $new->{position_sensitive} = 1; $x }	509	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
419	sub TY() { $new->{position_sensitive} = 1; $y }	510	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
420	sub TW() { $new->{size_sensitive} = 1; $w }	511	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
421	sub TH() { $new->{size_sensitive} = 1; $h }	512	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
422		513
423	=item now	514	=item now
424		515
425	Returns the current time as (fractional) seconds since the epoch.	516	Returns the current time as (fractional) seconds since the epoch.
426		517
…		…
433	C<$seconds> seconds.	524	C<$seconds> seconds.
434		525
435	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
436	the hour pointer of a clock). Update this image every minute.	527	the hour pointer of a clock). Update this image every minute.
437		528
		529	again 60;
438	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" }
439		531
440	=item counter $seconds	532	=item counter $seconds
441		533
442	Like C<again>, but also returns an increasing counter value, starting at	534	Like C<again>, but also returns an increasing counter value, starting at
443	0, which might be useful for some simple animation effects.	535	0, which might be useful for some simple animation effects.
…		…
445	=cut	537	=cut
446		538
447	sub now() { urxvt::NOW }	539	sub now() { urxvt::NOW }
448		540
449	sub again($) {	541	sub again($) {
450	$new->{again} = $_[0];	542	$frame->[FR_AGAIN]{time} = $_[0];
451	}	543	}
452		544
453	sub counter($) {	545	sub counter($) {
454	$new->{again} = $_[0];	546	$frame->[FR_AGAIN]{time} = $_[0];
455	$self->{counter} + 0	547	$frame->[FR_STATE]{counter} + 0
456	}	548	}
457		549
458	=back	550	=back
459		551
460	=head2 SHAPE CHANGING OPERATORS	552	=head2 SHAPE CHANGING OPERATORS
…		…
480	assumed.	572	assumed.
481		573
482	Example: load an image, blur it, and clip it to the window size to save	574	Example: load an image, blur it, and clip it to the window size to save
483	memory.	575	memory.
484		576
485	clip blur 10, load "mybg.png"	577	clip keep { blur 10, load "mybg.png" }
486		578
487	=cut	579	=cut
488		580
489	sub clip($;$$;$$) {	581	sub clip($;$$;$$) {
490	my $img = pop;	582	my $img = pop;
…		…
584	the terminal window (or the box specified by C<$width> and C<$height> if	676	the terminal window (or the box specified by C<$width> and C<$height> if
585	given).	677	given).
586		678
587	Example: load an image and center it.	679	Example: load an image and center it.
588		680
589	center pad load "mybg.png"	681	center keep { pad load "mybg.png" }
590		682
591	=item rootalign $img	683	=item rootalign $img
592		684
593	Moves the image so that it appears glued to the screen as opposed to the	685	Moves the image so that it appears glued to the screen as opposed to the
594	window. This gives the illusion of a larger area behind the window. It is	686	window. This gives the illusion of a larger area behind the window. It is
595	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	687	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
596	top left of the screen.	688	top left of the screen.
597		689
598	Example: load a background image, put it in mirror mode and root align it.	690	Example: load a background image, put it in mirror mode and root align it.
599		691
600	rootalign mirror load "mybg.png"	692	rootalign keep { mirror load "mybg.png" }
601		693
602	Example: take the screen background and align it, giving the illusion of	694	Example: take the screen background and align it, giving the illusion of
603	transparency as long as the window isn't in front of other windows.	695	transparency as long as the window isn't in front of other windows.
604		696
605	rootalign root	697	rootalign root
…		…
630		722
631	sub rootalign($) {	723	sub rootalign($) {
632	move -TX, -TY, $_[0]	724	move -TX, -TY, $_[0]
633	}	725	}
634		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($$$$) {
		739	my $img = pop;
		740	$img->rotate (
		741	$_[0] * ($img->w + $img->x),
		742	$_[1] * ($img->h + $img->y),
		743	$_[2] * (3.14159265 / 180),
		744	)
		745	}
		746
635	=back	747	=back
636		748
637	=head2 COLOUR MODIFICATIONS	749	=head2 COLOUR MODIFICATIONS
638		750
639	The following operators change the pixels of the image.	751	The following operators change the pixels of the image.
640		752
641	=over 4	753	=over 4
		754
		755	=item tint $color, $img
		756
		757	Tints the image in the given colour.
		758
		759	Example: tint the image red.
		760
		761	tint "red", load "rgb.png"
		762
		763	Example: the same, but specify the colour by component.
		764
		765	tint [1, 0, 0], load "rgb.png"
		766
		767	=cut
		768
		769	sub tint($$) {
		770	$_[1]->tint ($_[0])
		771	}
642		772
643	=item contrast $factor, $img	773	=item contrast $factor, $img
644		774
645	=item contrast $r, $g, $b, $img	775	=item contrast $r, $g, $b, $img
646		776
…		…
673		803
674	Values less than 0 reduce brightness, while values larger than 0 increase	804	Values less than 0 reduce brightness, while values larger than 0 increase
675	it. Useful range is from -1 to 1 - the former results in a black, the	805	it. Useful range is from -1 to 1 - the former results in a black, the
676	latter in a white picture.	806	latter in a white picture.
677		807
678	Due to idiosynchrasies in the underlying XRender extension, biases less	808	Due to idiosyncrasies in the underlying XRender extension, biases less
679	than zero can be I<very> slow.	809	than zero can be I<very> slow.
680		810
681	=cut	811	=cut
682		812
683	sub contrast($$;$$;$) {	813	sub contrast($$;$$;$) {
…		…
721	sub blur($$;$) {	851	sub blur($$;$) {
722	my $img = pop;	852	my $img = pop;
723	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	853	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
724	}	854	}
725		855
726	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
727
728	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
729	pointer at C<$center_x> and C<$center_y> (specified as factor of image
730	width/height), generating a new image with width C<$new_width> and height
731	C<$new_height>.
732
733	#TODO# new width, height, maybe more operators?
734
735	Example: rotate the image by 90 degrees
736
737	=cut
738
739	sub rotate($$$$$$) {
740	my $img = pop;
741	$img->rotate (
742	$_[0],
743	$_[1],
744	$_[2] * $img->w,
745	$_[3] * $img->h,
746	$_[4] * (3.14159265 / 180),
747	)
748	}
749
750	=back	856	=back
751		857
		858	=head2 OTHER STUFF
		859
		860	Anything that didn't fit any of the other categories, even after applying
		861	force and closing our eyes.
		862
		863	=over 4
		864
		865	=item keep { ... }
		866
		867	This operator takes a code block as argument, that is, one or more
		868	statements enclosed by braces.
		869
		870	The trick is that this code block is only evaluated when the outcome
		871	changes - on other calls the C<keep> simply returns the image it computed
		872	previously (yes, it should only be used with images). Or in other words,
		873	C<keep> I<caches> the result of the code block so it doesn't need to be
		874	computed again.
		875
		876	This can be extremely useful to avoid redoing slow operations - for
		877	example, if your background expression takes the root background, blurs it
		878	and then root-aligns it it would have to blur the root background on every
		879	window move or resize.
		880
		881	Another example is C<load>, which can be quite slow.
		882
		883	In fact, urxvt itself encloses the whole expression in some kind of
		884	C<keep> block so it only is reevaluated as required.
		885
		886	Putting the blur into a C<keep> block will make sure the blur is only done
		887	once, while the C<rootalign> is still done each time the window moves.
		888
		889	rootlign keep { blur 10, root }
		890
		891	This leaves the question of how to force reevaluation of the block,
		892	in case the root background changes: If expression inside the block
		893	is sensitive to some event (root background changes, window geometry
		894	changes), then it will be reevaluated automatically as needed.
		895
		896	=cut
		897
		898	sub keep(&) {
		899	my $id = $_[0]+0;
		900
		901	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		902
		903	unless ($frame->[FR_CACHE]) {
		904	$frame->[FR_CACHE] = [ $_[0]() ];
		905
		906	my $self = $self;
		907	my $frame = $frame;
		908	Scalar::Util::weaken $frame;
		909	$self->compile_frame ($frame, sub {
		910	# clear this frame cache, also for all parents
		911	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		912	undef $frame->[FR_CACHE];
		913	}
		914
		915	$self->recalculate;
		916	});
		917	};
		918
		919	# in scalar context we always return the first original result, which
		920	# is not quite how perl works.
		921	wantarray
		922	? @{ $frame->[FR_CACHE] }
		923	: $frame->[FR_CACHE][0]
		924	}
		925
		926	# sub keep_clear() {
		927	# delete $self->{frame_cache};
		928	# }
		929
		930	=back
		931
752	=cut	932	=cut
753		933
754	}	934	}
755		935
756	sub parse_expr {	936	sub parse_expr {
757	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	937	my $expr = eval
		938	"sub {\n"
		939	. "package urxvt::bgdsl;\n"
		940	. "#line 0 'background expression'\n"
		941	. "$_[0]\n"
		942	. "}";
758	die if $@;	943	die if $@;
759	$expr	944	$expr
760	}	945	}
761		946
762	# compiles a parsed expression	947	# compiles a parsed expression
763	sub set_expr {	948	sub set_expr {
764	my ($self, $expr) = @_;	949	my ($self, $expr) = @_;
765		950
		951	$self->{root} = [];
766	$self->{expr} = $expr;	952	$self->{expr} = $expr;
767	$self->recalculate;	953	$self->recalculate;
		954	}
		955
		956	# takes a hash of sensitivity indicators and installs watchers
		957	sub compile_frame {
		958	my ($self, $frame, $cb) = @_;
		959
		960	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		961	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		962
		963	# don't keep stuff alive
		964	Scalar::Util::weaken $state;
		965
		966	if ($again->{nested}) {
		967	$state->{nested} = 1;
		968	} else {
		969	delete $state->{nested};
		970	}
		971
		972	if (my $interval = $again->{time}) {
		973	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		974	if $state->{time}[0] != $interval;
		975
		976	# callback might have changed, although we could just rule that out
		977	$state->{time}[1]->cb (sub {
		978	++$state->{counter};
		979	$cb->();
		980	});
		981	} else {
		982	delete $state->{time};
		983	}
		984
		985	if ($again->{position}) {
		986	$state->{position} = $self->on (position_change => $cb);
		987	} else {
		988	delete $state->{position};
		989	}
		990
		991	if ($again->{size}) {
		992	$state->{size} = $self->on (size_change => $cb);
		993	} else {
		994	delete $state->{size};
		995	}
		996
		997	if ($again->{rootpmap}) {
		998	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		999	} else {
		1000	delete $state->{rootpmap};
		1001	}
768	}	1002	}
769		1003
770	# evaluate the current bg expression	1004	# evaluate the current bg expression
771	sub recalculate {	1005	sub recalculate {
772	my ($arg_self) = @_;	1006	my ($arg_self) = @_;
…		…
782		1016
783	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1017	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
784		1018
785	# set environment to evaluate user expression	1019	# set environment to evaluate user expression
786		1020
787	local $self = $arg_self;	1021	local $self = $arg_self;
788
789	local $HOME = $ENV{HOME};	1022	local $HOME = $ENV{HOME};
790	local $old = $self->{state};	1023	local $frame = [];
791	local $new = my $state = $self->{state} = {};
792		1024
793	($x, $y, $w, $h) =
794	$self->background_geometry ($self->{border});	1025	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
795		1026
796	# evaluate user expression	1027	# evaluate user expression
797		1028
798	my $img = eval { $self->{expr}->() };	1029	my @img = eval { $self->{expr}->() };
799	warn $@ if $@;#d#	1030	die $@ if $@;
800	die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";	1031	die "background-expr did not return anything.\n" unless @img;
		1032	die "background-expr: expected image(s), got something else.\n"
		1033	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
801		1034
802	$state->{size_sensitive} = 1	1035	my $img = urxvt::bgdsl::merge @img;
		1036
		1037	$frame->[FR_AGAIN]{size} = 1
803	if $img->repeat_mode != urxvt::RepeatNormal;	1038	if $img->repeat_mode != urxvt::RepeatNormal;
804		1039
805	# if the expression is sensitive to external events, prepare reevaluation then	1040	# if the expression is sensitive to external events, prepare reevaluation then
806		1041	$self->compile_frame ($frame, sub { $arg_self->recalculate });
807	my $repeat;
808
809	if (my $again = $state->{again}) {
810	$repeat = 1;
811	my $self = $self;
812	$state->{timer} = $again == $old->{again}
813	? $old->{timer}
814	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
815	++$self->{counter};
816	$self->recalculate
817	});
818	}
819
820	if (delete $state->{position_sensitive}) {
821	$repeat = 1;
822	$self->enable (position_change => sub { $_[0]->recalculate });
823	} else {
824	$self->disable ("position_change");
825	}
826
827	if (delete $state->{size_sensitive}) {
828	$repeat = 1;
829	$self->enable (size_change => sub { $_[0]->recalculate });
830	} else {
831	$self->disable ("size_change");
832	}
833
834	if (delete $state->{rootpmap_sensitive}) {
835	$repeat = 1;
836	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
837	} else {
838	$self->disable ("rootpmap_change");
839	}
840		1042
841	# clear stuff we no longer need	1043	# clear stuff we no longer need
842		1044
843	%$old = ();	1045	# unless (%{ $frame->[FR_STATE] }) {
844
845	unless ($repeat) {
846	delete $self->{state};	1046	# delete $self->{state};
847	delete $self->{expr};	1047	# delete $self->{expr};
848	}	1048	# }
849		1049
850	# set background pixmap	1050	# set background pixmap
851		1051
852	$self->set_background ($img, $self->{border});	1052	$self->set_background ($img, $self->{border});
853	$self->scr_recolour (0);	1053	$self->scr_recolour (0);

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.50 by root, Sun Jun 10 17:31:53 2012 UTC vs. Revision 1.70 by root, Mon Jul 2 01:35:37 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.50 by root, Sun Jun 10 17:31:53 2012 UTC vs.
Revision 1.70 by root, Mon Jul 2 01:35:37 2012 UTC