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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.58 by root, Thu Jun 14 18:13:19 2012 UTC vs.
Revision 1.73 by sf-exg, Thu Jul 5 20:05:19 2012 UTC

…		…
26	to be as simple as possible.	26	to be as simple as possible.
27		27
28	For example, to load an image and scale it to the window size, you would	28	For example, to load an image and scale it to the window size, you would
29	use:	29	use:
30		30
31	urxvt --background-expr 'scale load "/path/to/mybg.png"'	31	urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
32		32
33	Or specified as a X resource:	33	Or specified as a X resource:
34		34
35	URxvt.background-expr: scale load "/path/to/mybg.png"	35	URxvt.background-expr: scale keep { load "/path/to/mybg.png" }
36		36
37	=head1 THEORY OF OPERATION	37	=head1 THEORY OF OPERATION
38		38
39	At startup, just before the window is mapped for the first time, the	39	At startup, just before the window is mapped for the first time, the
40	expression is evaluated and must yield an image. The image is then	40	expression is evaluated and must yield an image. The image is then
…		…
53	If any of the parameters that the expression relies on changes (when the	53	If any of the parameters that the expression relies on changes (when the
54	window is moved or resized, its position or size changes; when the root	54	window is moved or resized, its position or size changes; when the root
55	pixmap is replaced by another one the root background changes; or when the	55	pixmap is replaced by another one the root background changes; or when the
56	timer elapses), then the expression will be evaluated again.	56	timer elapses), then the expression will be evaluated again.
57		57
58	For example, an expression such as C<scale load "$HOME/mybg.png"> scales the	58	For example, an expression such as C<scale keep { load "$HOME/mybg.png"
59	image to the window size, so it relies on the window size and will	59	}> scales the image to the window size, so it relies on the window size
60	be reevaluated each time it is changed, but not when it moves for	60	and will be reevaluated each time it is changed, but not when it moves for
61	example. That ensures that the picture always fills the terminal, even	61	example. That ensures that the picture always fills the terminal, even
62	after its size changes.	62	after its size changes.
63		63
64	=head2 EXPRESSIONS	64	=head2 EXPRESSIONS
65		65
66	Expressions are normal Perl expressions, in fact, they are Perl blocks -	66	Expressions are normal Perl expressions, in fact, they are Perl blocks -
67	which means you could use multiple lines and statements:	67	which means you could use multiple lines and statements:
68		68
		69	scale keep {
69	again 3600;	70	again 3600;
70	if (localtime now)[6]) {	71	if (localtime now)[6]) {
71	return scale load "$HOME/weekday.png";	72	return load "$HOME/weekday.png";
72	} else {	73	} else {
73	return scale load "$HOME/sunday.png";	74	return load "$HOME/sunday.png";
		75	}
74	}	76	}
75		77
76	This expression is evaluated once per hour. It will set F<sunday.png> as	78	This inner expression is evaluated once per hour (and whenever the
		79	terminal window is resized). It sets F<sunday.png> as background on
77	background on Sundays, and F<weekday.png> on all other days.	80	Sundays, and F<weekday.png> on all other days.
78		81
79	Fortunately, we expect that most expressions will be much simpler, with	82	Fortunately, we expect that most expressions will be much simpler, with
80	little Perl knowledge needed.	83	little Perl knowledge needed.
81		84
82	Basically, you always start with a function that "generates" an image	85	Basically, you always start with a function that "generates" an image
…		…
115	horizontal and vertical dimensions. For example, this halves the image	118	horizontal and vertical dimensions. For example, this halves the image
116	width and doubles the image height:	119	width and doubles the image height:
117		120
118	scale 0.5, 2, load "$HOME/mypic.png"	121	scale 0.5, 2, load "$HOME/mypic.png"
119		122
120	Other effects than scaling are also readily available, for example, you can	123	IF you try out these expressions, you might suffer from some sluggishness,
121	tile the image to fill the whole window, instead of resizing it:	124	because each time the terminal is resized, it loads the PNG image again
		125	and scales it. Scaling is usually fast (and unavoidable), but loading the
		126	image can be quite time consuming. This is where C<keep> comes in handy:
122		127
		128	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		129
		130	The C<keep> operator executes all the statements inside the braces only
		131	once, or when it thinks the outcome might change. In other cases it
		132	returns the last value computed by the brace block.
		133
		134	This means that the C<load> is only executed once, which makes it much
		135	faster, but also means that more memory is being used, because the loaded
		136	image must be kept in memory at all times. In this expression, the
		137	trade-off is likely worth it.
		138
		139	But back to effects: Other effects than scaling are also readily
		140	available, for example, you can tile the image to fill the whole window,
		141	instead of resizing it:
		142
123	tile load "$HOME/mypic.png"	143	tile keep { load "$HOME/mypic.png" }
124		144
125	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator	145	In fact, images returned by C<load> are in C<tile> mode by default, so the
126	is kind of superfluous.	146	C<tile> operator is kind of superfluous.
127		147
128	Another common effect is to mirror the image, so that the same edges touch:	148	Another common effect is to mirror the image, so that the same edges
		149	touch:
129		150
130	mirror load "$HOME/mypic.png"	151	mirror keep { load "$HOME/mypic.png" }
131		152
132	This is also a typical background expression:	153	Another common background expression is:
133		154
134	rootalign root	155	rootalign root
135		156
136	It first takes a snapshot of the screen background image, and then	157	This one first takes a snapshot of the screen background image, and then
137	moves it to the upper left corner of the screen - the result is	158	moves it to the upper left corner of the screen (as opposed to the upper
138	pseudo-transparency, as the image seems to be static while the window is	159	left corner of the terminal window)- the result is pseudo-transparency:
139	moved around.	160	the image seems to be static while the window is moved around.
140		161
141	=head2 CYCLES AND CACHING	162	=head2 COLOUR SPECIFICATIONS
142		163
143	As has been mentioned before, the expression might be evaluated multiple	164	Whenever an operator expects a "colour", then this can be specified in one
144	times. Each time the expression is reevaluated, a new cycle is said to	165	of two ways: Either as string with an X11 colour specification, such as:
145	have begun. Many operators cache their results till the next cycle.
146		166
147	For example, the C<load> operator keeps a copy of the image. If it is	167	"red" # named colour
148	asked to load the same image on the next cycle it will not load it again,	168	"#f00" # simple rgb
149	but return the cached copy.	169	"[50]red" # red with 50% alpha
		170	"TekHVC:300/50/50" # anything goes
150		171
151	This only works for one cycle though, so as long as you load the same	172	OR as an array reference with one, three or four components:
152	image every time, it will always be cached, but when you load a different
153	image, it will forget about the first one.
154		173
155	This allows you to either speed things up by keeping multiple images in	174	[0.5] # 50% gray, 100% alpha
156	memory, or conserve memory by loading images more often.	175	[0.5, 0, 0] # dark red, no green or blur, 100% alpha
		176	[0.5, 0, 0, 0.7] # same with explicit 70% alpha
157		177
158	For example, you can keep two images in memory and use a random one like	178	=head2 CACHING AND SENSITIVITY
159	this:
160		179
161	my $img1 = load "img1.png";	180	Since some operations (such as C<load> and C<blur>) can take a long time,
162	my $img2 = load "img2.png";	181	caching results can be very important for a smooth operation. Caching can
163	(0.5 > rand) ? $img1 : $img2	182	also be useful to reduce memory usage, though, for example, when an image
		183	is cached by C<load>, it could be shared by multiple terminal windows
		184	running inside urxvtd.
164		185
165	Since both images are "loaded" every time the expression is evaluated,	186	=head3 C<keep { ... }> caching
166	they are always kept in memory. Contrast this version:
167		187
168	my $path1 = "img1.png";	188	The most important way to cache expensive operations is to use C<keep {
169	my $path2 = "img2.png";	189	... }>. The C<keep> operator takes a block of multiple statements enclosed
170	load ((0.5 > rand) ? $path1 : $path2)	190	by C<{}> and keeps the return value in memory.
171		191
172	Here, a path is selected randomly, and load is only called for one image,	192	An expression can be "sensitive" to various external events, such as
173	so keeps only one image in memory. If, on the next evaluation, luck	193	scaling or moving the window, root background changes and timers. Simply
174	decides to use the other path, then it will have to load that image again.	194	using an expression (such as C<scale> without parameters) that depends on
		195	certain changing values (called "variables"), or using those variables
		196	directly, will make an expression sensitive to these events - for example,
		197	using C<scale> or C<TW> will make the expression sensitive to the terminal
		198	size, and thus to resizing events.
		199
		200	When such an event happens, C<keep> will automatically trigger a
		201	reevaluation of the whole expression with the new value of the expression.
		202
		203	C<keep> is most useful for expensive operations, such as C<blur>:
		204
		205	rootalign keep { blur 20, root }
		206
		207	This makes a blurred copy of the root background once, and on subsequent
		208	calls, just root-aligns it. Since C<blur> is usually quite slow and
		209	C<rootalign> is quite fast, this trades extra memory (for the cached
		210	blurred pixmap) with speed (blur only needs to be redone when root
		211	changes).
		212
		213	=head3 C<load> caching
		214
		215	The C<load> operator itself does not keep images in memory, but as long as
		216	the image is still in memory, C<load> will use the in-memory image instead
		217	of loading it freshly from disk.
		218
		219	That means that this expression:
		220
		221	keep { load "$HOME/path..." }
		222
		223	Not only caches the image in memory, other terminal instances that try to
		224	C<load> it can reuse that in-memory copy.
175		225
176	=head1 REFERENCE	226	=head1 REFERENCE
177		227
178	=head2 COMMAND LINE SWITCHES	228	=head2 COMMAND LINE SWITCHES
179		229
…		…
204		254
205	=cut	255	=cut
206		256
207	our %_IMG_CACHE;	257	our %_IMG_CACHE;
208	our $HOME;	258	our $HOME;
209	our ($self, $old, $new);	259	our ($self, $frame);
210	our ($x, $y, $w, $h);	260	our ($x, $y, $w, $h);
211		261
212	# enforce at least this interval between updates	262	# enforce at least this interval between updates
213	our $MIN_INTERVAL = 6/59.951;	263	our $MIN_INTERVAL = 6/59.951;
214		264
215	{	265	{
216	package urxvt::bgdsl; # background language	266	package urxvt::bgdsl; # background language
		267
		268	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
		269	sub FR_CACHE () { 1 } # cached values
		270	sub FR_AGAIN () { 2 } # what this expr is sensitive to
		271	sub FR_STATE () { 3 } # watchers etc.
217		272
218	use List::Util qw(min max sum shuffle);	273	use List::Util qw(min max sum shuffle);
219		274
220	=head2 PROVIDERS/GENERATORS	275	=head2 PROVIDERS/GENERATORS
221		276
…		…
228	=item load $path	283	=item load $path
229		284
230	Loads the image at the given C<$path>. The image is set to plane tiling	285	Loads the image at the given C<$path>. The image is set to plane tiling
231	mode.	286	mode.
232		287
233	Loaded images will be cached for one cycle, and shared between temrinals	288	If the image is already in memory (e.g. because another terminal instance
234	running in the same process (e.g. in C<urxvtd>).	289	uses it), then the in-memory copy us returned instead.
235		290
236	=item load_uc $path	291	=item load_uc $path
237		292
238	Load uncached - same as load, but does not cache the image. This function	293	Load uncached - same as load, but does not cache the image, which means it
239	is most useufl if you want to optimise a background expression in some	294	is I<always> loaded from the filesystem again, even if another copy of it
240	way.	295	is in memory at the time.
241		296
242	=cut	297	=cut
243		298
244	sub load_uc($) {	299	sub load_uc($) {
		300	$self->new_img_from_file ($_[0])
		301	}
		302
		303	sub load($) {
245	my ($path) = @_;	304	my ($path) = @_;
246		305
247	$_IMG_CACHE{$path} \|\| do {	306	$_IMG_CACHE{$path} \|\| do {
248	my $img = $self->new_img_from_file ($path);	307	my $img = load_uc $path;
249	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);	308	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
250	$img	309	$img
251	}	310	}
252	}	311	}
253		312
254	sub load($) {
255	my ($path) = @_;
256
257	$new->{load}{$path} = $old->{load}{$path} \|\| load_uc $path;
258	}
259
260	=item root	313	=item root
261		314
262	Returns the root window pixmap, that is, hopefully, the background image	315	Returns the root window pixmap, that is, hopefully, the background image
263	of your screen. The image is set to extend mode.	316	of your screen.
264		317
265	This function makes your expression root sensitive, that means it will be	318	This function makes your expression root sensitive, that means it will be
266	reevaluated when the bg image changes.	319	reevaluated when the bg image changes.
267		320
268	=cut	321	=cut
269		322
270	sub root() {	323	sub root() {
271	$new->{again}{rootpmap} = 1;	324	$frame->[FR_AGAIN]{rootpmap} = 1;
272	$self->new_img_from_root	325	$self->new_img_from_root
273	}	326	}
274		327
275	=item solid $colour	328	=item solid $colour
276		329
…		…
285	=cut	338	=cut
286		339
287	sub solid($;$$) {	340	sub solid($;$$) {
288	my $colour = pop;	341	my $colour = pop;
289		342
290	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	343	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
291	$img->fill ($colour);	344	$img->fill ($colour);
292	$img	345	$img
293	}	346	}
294		347
295	=item clone $img	348	=item clone $img
…		…
304	}	357	}
305		358
306	=item merge $img ...	359	=item merge $img ...
307		360
308	Takes any number of images and merges them together, creating a single	361	Takes any number of images and merges them together, creating a single
309	image containing them all.	362	image containing them all. The tiling mode of the first image is used as
		363	the tiling mode of the resulting image.
		364
		365	This function is called automatically when an expression returns multiple
		366	images.
310		367
311	=cut	368	=cut
312		369
313	sub merge(@) {	370	sub merge(@) {
		371	return $_[0] unless $#_;
		372
314	# rather annoyingly clumsy, but optimisation is for another time	373	# rather annoyingly clumsy, but optimisation is for another time
315		374
316	my $x0 = 1e9;	375	my $x0 = +1e9;
317	my $y0 = 1e9;	376	my $y0 = +1e9;
318	my $x1 = -1e9;	377	my $x1 = -1e9;
319	my $y1 = -1e9;	378	my $y1 = -1e9;
320		379
321	for (@_) {	380	for (@_) {
322	my ($x, $y, $w, $h) = $_->geometry;	381	my ($x, $y, $w, $h) = $_->geometry;
…		…
325	$y0 = $y if $y0 > $y;	384	$y0 = $y if $y0 > $y;
326		385
327	$x += $w;	386	$x += $w;
328	$y += $h;	387	$y += $h;
329		388
330	$x1 = $x if $x1 > $x;	389	$x1 = $x if $x1 < $x;
331	$y1 = $y if $y1 > $y;	390	$y1 = $y if $y1 < $y;
332	}	391	}
333		392
334	my $base = $self->new_img ($x0, $y0, $x1 - $x0, $y1 - $y0);	393	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		394	$base->repeat_mode ($_[0]->repeat_mode);
335	$base->fill ([0, 0, 0, 0]);	395	$base->fill ([0, 0, 0, 0]);
336		396
337	$base->blend (1., $_)	397	$base->draw ($_)
338	for @_;	398	for @_;
339		399
340	$base	400	$base
341	}	401	}
342		402
…		…
443	Using these functions make your expression sensitive to window moves.	503	Using these functions make your expression sensitive to window moves.
444		504
445	These functions are mainly useful to align images to the root window.	505	These functions are mainly useful to align images to the root window.
446		506
447	Example: load an image and align it so it looks as if anchored to the	507	Example: load an image and align it so it looks as if anchored to the
448	background.	508	background (that's exactly what C<rootalign> does btw.):
449		509
450	move -TX, -TY, load "mybg.png"	510	move -TX, -TY, keep { load "mybg.png" }
451		511
452	=item TW	512	=item TW
453		513
454	Return the width (C<TW>) and height (C<TH>) of the terminal window (the	514	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
455	terminal window is the full window by default, and the character area only	515	terminal window is the full window by default, and the character area only
…		…
461	the window size to conserve memory.	521	the window size to conserve memory.
462		522
463	Example: take the screen background, clip it to the window size, blur it a	523	Example: take the screen background, clip it to the window size, blur it a
464	bit, align it to the window position and use it as background.	524	bit, align it to the window position and use it as background.
465		525
466	clip move -TX, -TY, once { blur 5, root }	526	clip move -TX, -TY, keep { blur 5, root }
467		527
468	=cut	528	=cut
469		529
470	sub TX() { $new->{again}{position} = 1; $x }	530	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
471	sub TY() { $new->{again}{position} = 1; $y }	531	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
472	sub TW() { $new->{again}{size} = 1; $w }	532	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
473	sub TH() { $new->{again}{size} = 1; $h }	533	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
474		534
475	=item now	535	=item now
476		536
477	Returns the current time as (fractional) seconds since the epoch.	537	Returns the current time as (fractional) seconds since the epoch.
478		538
…		…
485	C<$seconds> seconds.	545	C<$seconds> seconds.
486		546
487	Example: load some image and rotate it according to the time of day (as if it were	547	Example: load some image and rotate it according to the time of day (as if it were
488	the hour pointer of a clock). Update this image every minute.	548	the hour pointer of a clock). Update this image every minute.
489		549
		550	again 60;
490	again 60; rotate 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"	551	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
491		552
492	=item counter $seconds	553	=item counter $seconds
493		554
494	Like C<again>, but also returns an increasing counter value, starting at	555	Like C<again>, but also returns an increasing counter value, starting at
495	0, which might be useful for some simple animation effects.	556	0, which might be useful for some simple animation effects.
…		…
497	=cut	558	=cut
498		559
499	sub now() { urxvt::NOW }	560	sub now() { urxvt::NOW }
500		561
501	sub again($) {	562	sub again($) {
502	$new->{again}{time} = $_[0];	563	$frame->[FR_AGAIN]{time} = $_[0];
503	}	564	}
504		565
505	sub counter($) {	566	sub counter($) {
506	$new->{again}{time} = $_[0];	567	$frame->[FR_AGAIN]{time} = $_[0];
507	$self->{counter} + 0	568	$frame->[FR_STATE]{counter} + 0
508	}	569	}
509		570
510	=back	571	=back
511		572
512	=head2 SHAPE CHANGING OPERATORS	573	=head2 SHAPE CHANGING OPERATORS
…		…
532	assumed.	593	assumed.
533		594
534	Example: load an image, blur it, and clip it to the window size to save	595	Example: load an image, blur it, and clip it to the window size to save
535	memory.	596	memory.
536		597
537	clip blur 10, load "mybg.png"	598	clip keep { blur 10, load "mybg.png" }
538		599
539	=cut	600	=cut
540		601
541	sub clip($;$$;$$) {	602	sub clip($;$$;$$) {
542	my $img = pop;	603	my $img = pop;
…		…
636	the terminal window (or the box specified by C<$width> and C<$height> if	697	the terminal window (or the box specified by C<$width> and C<$height> if
637	given).	698	given).
638		699
639	Example: load an image and center it.	700	Example: load an image and center it.
640		701
641	center pad load "mybg.png"	702	center keep { pad load "mybg.png" }
642		703
643	=item rootalign $img	704	=item rootalign $img
644		705
645	Moves the image so that it appears glued to the screen as opposed to the	706	Moves the image so that it appears glued to the screen as opposed to the
646	window. This gives the illusion of a larger area behind the window. It is	707	window. This gives the illusion of a larger area behind the window. It is
647	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	708	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
648	top left of the screen.	709	top left of the screen.
649		710
650	Example: load a background image, put it in mirror mode and root align it.	711	Example: load a background image, put it in mirror mode and root align it.
651		712
652	rootalign mirror load "mybg.png"	713	rootalign keep { mirror load "mybg.png" }
653		714
654	Example: take the screen background and align it, giving the illusion of	715	Example: take the screen background and align it, giving the illusion of
655	transparency as long as the window isn't in front of other windows.	716	transparency as long as the window isn't in front of other windows.
656		717
657	rootalign root	718	rootalign root
…		…
682		743
683	sub rootalign($) {	744	sub rootalign($) {
684	move -TX, -TY, $_[0]	745	move -TX, -TY, $_[0]
685	}	746	}
686		747
687	=item rotate $center_x, $center_y, $degrees	748	=item rotate $center_x, $center_y, $degrees, $img
688		749
689	Rotates the image by C<$degrees> degrees, counter-clockwise, around the	750	Rotates the image clockwise by C<$degrees> degrees, around the point at
690	pointer at C<$center_x> and C<$center_y> (specified as factor of image	751	C<$center_x> and C<$center_y> (specified as factor of image width/height).
691	width/height).
692		752
693	#TODO# new width, height, maybe more operators?
694
695	Example: rotate the image by 90 degrees	753	Example: rotate the image by 90 degrees around it's center.
		754
		755	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
696		756
697	=cut	757	=cut
698		758
699	sub rotate($$$$) {	759	sub rotate($$$$) {
700	my $img = pop;	760	my $img = pop;
701	$img->rotate (	761	$img->rotate (
702	$_[0] * $img->w,	762	$_[0] * ($img->w + $img->x),
703	$_[1] * $img->h,	763	$_[1] * ($img->h + $img->y),
704	$_[2] * (3.14159265 / 180),	764	$_[2] * (3.14159265 / 180),
705	)	765	)
706	}	766	}
707		767
708	=back	768	=back
…		…
710	=head2 COLOUR MODIFICATIONS	770	=head2 COLOUR MODIFICATIONS
711		771
712	The following operators change the pixels of the image.	772	The following operators change the pixels of the image.
713		773
714	=over 4	774	=over 4
		775
		776	=item tint $color, $img
		777
		778	Tints the image in the given colour.
		779
		780	Example: tint the image red.
		781
		782	tint "red", load "rgb.png"
		783
		784	Example: the same, but specify the colour by component.
		785
		786	tint [1, 0, 0], load "rgb.png"
		787
		788	=cut
		789
		790	sub tint($$) {
		791	$_[1]->tint ($_[0])
		792	}
715		793
716	=item contrast $factor, $img	794	=item contrast $factor, $img
717		795
718	=item contrast $r, $g, $b, $img	796	=item contrast $r, $g, $b, $img
719		797
…		…
803	Anything that didn't fit any of the other categories, even after applying	881	Anything that didn't fit any of the other categories, even after applying
804	force and closing our eyes.	882	force and closing our eyes.
805		883
806	=over 4	884	=over 4
807		885
808	=item once { ... }	886	=item keep { ... }
809		887
810	This function takes a code block as argument, that is, one or more	888	This operator takes a code block as argument, that is, one or more
811	statements enclosed by braces.	889	statements enclosed by braces.
812		890
813	The trick is that this code block is only evaluated once - future calls	891	The trick is that this code block is only evaluated when the outcome
814	will simply return the original image (yes, it should only be used with	892	changes - on other calls the C<keep> simply returns the image it computed
815	images).	893	previously (yes, it should only be used with images). Or in other words,
		894	C<keep> I<caches> the result of the code block so it doesn't need to be
		895	computed again.
816		896
817	This can be extremely useful to avoid redoign the same slow operations	897	This can be extremely useful to avoid redoing slow operations - for
818	again and again- for example, if your background expression takes the root	898	example, if your background expression takes the root background, blurs it
819	background, blurs it and then root-aligns it it would have to blur the	899	and then root-aligns it it would have to blur the root background on every
820	root background on every window move or resize.	900	window move or resize.
821		901
		902	Another example is C<load>, which can be quite slow.
		903
		904	In fact, urxvt itself encloses the whole expression in some kind of
		905	C<keep> block so it only is reevaluated as required.
		906
822	Putting the blur into a C<once> block will make sure the blur is only done	907	Putting the blur into a C<keep> block will make sure the blur is only done
823	once:	908	once, while the C<rootalign> is still done each time the window moves.
824		909
825	rootlign once { blur 10, root }	910	rootalign keep { blur 10, root }
826		911
827	This leaves the question of how to force reevaluation of the block, in	912	This leaves the question of how to force reevaluation of the block,
828	case the root background changes: Right now, all once blocks forget that	913	in case the root background changes: If expression inside the block
829	they ahve been executed before each time the root background changes (if	914	is sensitive to some event (root background changes, window geometry
830	the expression is sensitive to that) or when C<once_again> is called.	915	changes), then it will be reevaluated automatically as needed.
831		916
832	=item once_again
833
834	Resets all C<once> block as if they had never been called, i.e. on the
835	next call they will be reevaluated again.
836
837	=cut	917	=cut
838		918
839	sub once(&) {	919	sub keep(&) {
840	my $once = $self->{once_cache}{$_[0]+0} \|\|= do {	920	my $id = $_[0]+0;
841	local $new->{again};	921
842	my @res = $_[0]();	922	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
843	[$new->{again}, \@res]	923
		924	unless ($frame->[FR_CACHE]) {
		925	$frame->[FR_CACHE] = [ $_[0]() ];
		926
		927	my $self = $self;
		928	my $frame = $frame;
		929	Scalar::Util::weaken $frame;
		930	$self->compile_frame ($frame, sub {
		931	# clear this frame cache, also for all parents
		932	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		933	undef $frame->[FR_CACHE];
		934	}
		935
		936	$self->recalculate;
844	};	937	});
845
846	$new->{again} = {
847	%{ $new->{again} },
848	%{ $once->[0] }
849	};	938	};
850		939
851	# in scalar context we always return the first original result, which	940	# in scalar context we always return the first original result, which
852	# is not quite how perl works.	941	# is not quite how perl works.
853	wantarray	942	wantarray
854	? @{ $once->[1] }	943	? @{ $frame->[FR_CACHE] }
855	: $once->[1][0]	944	: $frame->[FR_CACHE][0]
		945	}
		946
		947	# sub keep_clear() {
		948	# delete $self->{frame_cache};
856	}	949	# }
857
858	sub once_again() {
859	delete $self->{once_cache};
860	}
861		950
862	=back	951	=back
863		952
864	=cut	953	=cut
865		954
866	}	955	}
867		956
868	sub parse_expr {	957	sub parse_expr {
869	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	958	my $expr = eval
		959	"sub {\n"
		960	. "package urxvt::bgdsl;\n"
		961	. "#line 0 'background expression'\n"
		962	. "$_[0]\n"
		963	. "}";
870	die if $@;	964	die if $@;
871	$expr	965	$expr
872	}	966	}
873		967
874	# compiles a parsed expression	968	# compiles a parsed expression
875	sub set_expr {	969	sub set_expr {
876	my ($self, $expr) = @_;	970	my ($self, $expr) = @_;
877		971
		972	$self->{root} = [];
878	$self->{expr} = $expr;	973	$self->{expr} = $expr;
879	$self->recalculate;	974	$self->recalculate;
		975	}
		976
		977	# takes a hash of sensitivity indicators and installs watchers
		978	sub compile_frame {
		979	my ($self, $frame, $cb) = @_;
		980
		981	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		982	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		983
		984	# don't keep stuff alive
		985	Scalar::Util::weaken $state;
		986
		987	if ($again->{nested}) {
		988	$state->{nested} = 1;
		989	} else {
		990	delete $state->{nested};
		991	}
		992
		993	if (my $interval = $again->{time}) {
		994	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		995	if $state->{time}[0] != $interval;
		996
		997	# callback might have changed, although we could just rule that out
		998	$state->{time}[1]->cb (sub {
		999	++$state->{counter};
		1000	$cb->();
		1001	});
		1002	} else {
		1003	delete $state->{time};
		1004	}
		1005
		1006	if ($again->{position}) {
		1007	$state->{position} = $self->on (position_change => $cb);
		1008	} else {
		1009	delete $state->{position};
		1010	}
		1011
		1012	if ($again->{size}) {
		1013	$state->{size} = $self->on (size_change => $cb);
		1014	} else {
		1015	delete $state->{size};
		1016	}
		1017
		1018	if ($again->{rootpmap}) {
		1019	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		1020	} else {
		1021	delete $state->{rootpmap};
		1022	}
880	}	1023	}
881		1024
882	# evaluate the current bg expression	1025	# evaluate the current bg expression
883	sub recalculate {	1026	sub recalculate {
884	my ($arg_self) = @_;	1027	my ($arg_self) = @_;
…		…
894		1037
895	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1038	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
896		1039
897	# set environment to evaluate user expression	1040	# set environment to evaluate user expression
898		1041
899	local $self = $arg_self;	1042	local $self = $arg_self;
900
901	local $HOME = $ENV{HOME};	1043	local $HOME = $ENV{HOME};
902	local $old = $self->{state};	1044	local $frame = [];
903	local $new = my $state = $self->{state} = {};
904		1045
905	($x, $y, $w, $h) =
906	$self->background_geometry ($self->{border});	1046	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
907		1047
908	# evaluate user expression	1048	# evaluate user expression
909		1049
910	my $img = eval { $self->{expr}->() };	1050	my @img = eval { $self->{expr}->() };
911	warn $@ if $@;#d#	1051	die $@ if $@;
912	die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";	1052	die "background-expr did not return anything.\n" unless @img;
		1053	die "background-expr: expected image(s), got something else.\n"
		1054	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
		1055
		1056	my $img = urxvt::bgdsl::merge @img;
		1057
		1058	$frame->[FR_AGAIN]{size} = 1
		1059	if $img->repeat_mode != urxvt::RepeatNormal;
913		1060
914	# if the expression is sensitive to external events, prepare reevaluation then	1061	# if the expression is sensitive to external events, prepare reevaluation then
915		1062	$self->compile_frame ($frame, sub { $arg_self->recalculate });
916	my $again = delete $state->{again};
917
918	$again->{size} = 1
919	if $img->repeat_mode != urxvt::RepeatNormal;
920
921	if (my $again = $again->{time}) {
922	my $self = $self;
923	$state->{timer} = $again == $old->{again}
924	? $old->{timer}
925	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
926	++$self->{counter};
927	$self->recalculate
928	});
929	}
930
931	if ($again->{position}) {
932	$self->enable (position_change => sub { $_[0]->recalculate });
933	} else {
934	$self->disable ("position_change");
935	}
936
937	if ($again->{size}) {
938	$self->enable (size_change => sub { $_[0]->recalculate });
939	} else {
940	$self->disable ("size_change");
941	}
942
943	if ($again->{rootpmap}) {
944	$self->enable (rootpmap_change => sub {
945	delete $_[0]{once_cache}; # this will override once-block values from
946	$_[0]->recalculate;
947	});
948	} else {
949	$self->disable ("rootpmap_change");
950	}
951		1063
952	# clear stuff we no longer need	1064	# clear stuff we no longer need
953		1065
954	%$old = ();	1066	# unless (%{ $frame->[FR_STATE] }) {
955
956	unless (%$again) {
957	delete $self->{state};	1067	# delete $self->{state};
958	delete $self->{expr};	1068	# delete $self->{expr};
959	}	1069	# }
960		1070
961	# set background pixmap	1071	# set background pixmap
962		1072
963	$self->set_background ($img, $self->{border});	1073	$self->set_background ($img, $self->{border});
964	$self->scr_recolour (0);	1074	$self->scr_recolour (0);

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.58 by root, Thu Jun 14 18:13:19 2012 UTC vs. Revision 1.73 by sf-exg, Thu Jul 5 20:05:19 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.58 by root, Thu Jun 14 18:13:19 2012 UTC vs.
Revision 1.73 by sf-exg, Thu Jul 5 20:05:19 2012 UTC