[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 1.67 by sf-exg, Fri Jun 29 18:12:25 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 expression is evaluated once per hour. It will set F<sunday.png> as
77	background on Sundays, and F<weekday.png> on all other days.	79	background on Sundays, and F<weekday.png> on all other days.
78		80
79	Fortunately, we expect that most expressions will be much simpler, with	81	Fortunately, we expect that most expressions will be much simpler, with
80	little Perl knowledge needed.	82	little Perl knowledge needed.
81		83
…		…
115	horizontal and vertical dimensions. For example, this halves the image	117	horizontal and vertical dimensions. For example, this halves the image
116	width and doubles the image height:	118	width and doubles the image height:
117		119
118	scale 0.5, 2, load "$HOME/mypic.png"	120	scale 0.5, 2, load "$HOME/mypic.png"
119		121
120	Other effects than scalign are also readily available, for exmaple, you can	122	IF you try out these expressions, you might suffer from sluggishness,
121	tile the image to fill the whole window, instead of resizing it:	123	because each time the terminal is resized, it again loads the PNG image
		124	and scales it. Scaling is usually fast, but loading the image can be quite
		125	time consuming. This is where C<keep> comes in handy:
122		126
		127	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		128
		129	The C<keep> operator executes all the statements inside the braces only
		130	once, or when it thinks the outcome might change. In other cases it
		131	returns the last value computed by the brace block.
		132
		133	This means that the C<load> is only executed once, which makes it much
		134	faster, but also means that more memory is being used, because the loaded
		135	image must be kept in memory at all times. In this expression, the
		136	trade-off is likely worth it.
		137
		138	But back to effects: Other effects than scaling are also readily
		139	available, for example, you can tile the image to fill the whole window,
		140	instead of resizing it:
		141
123	tile load "$HOME/mypic.png"	142	tile keep { load "$HOME/mypic.png" }
124		143
125	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator	144	In fact, images returned by C<load> are in C<tile> mode by default, so the
126	is kind of superfluous.	145	C<tile> operator is kind of superfluous.
127		146
128	Another common effect is to mirror the image, so that the same edges touch:	147	Another common effect is to mirror the image, so that the same edges
		148	touch:
129		149
130	mirror load "$HOME/mypic.png"	150	mirror keep { load "$HOME/mypic.png" }
131		151
132	This is also a typical background expression:	152	Another common background expression is:
133		153
134	rootalign root	154	rootalign root
135		155
136	It first takes a snapshot of the screen background image, and then	156	This one first takes a snapshot of the screen background image, and then
137	moves it to the upper left corner of the screen - the result is	157	moves it to the upper left corner of the screen (as opposed to the upper
138	pseudo-transparency, as the image seems to be static while the window is	158	left corner of the terminal window)- the result is pseudo-transparency:
139	moved around.	159	the image seems to be static while the window is moved around.
140		160
141	=head2 CYCLES AND CACHING	161	=head2 CACHING AND SENSITIVITY
142		162
143	As has been mentioned before, the expression might be evaluated multiple	163	Since some operations (such as C<load> and C<blur>) can take a long time,
144	times. Each time the expression is reevaluated, a new cycle is said to	164	caching results can be very important for a smooth operation. Caching can
145	have begun. Many operators cache their results till the next cycle.	165	also be useful to reduce memory usage, though, for example, when an image
		166	is cached by C<load>, it could be shared by multiple terminal windows
		167	running inside urxvtd.
146		168
147	For example, the C<load> operator keeps a copy of the image. If it is	169	=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		170
151	This only works for one cycle though, so as long as you load the same	171	The most important way to cache expensive operations is to use C<keep {
152	image every time, it will always be cached, but when you load a different	172	... }>. The C<keep> operator takes a block of multiple statements enclosed
153	image, it will forget about the first one.	173	by C<{}> and keeps the return value in memory.
154		174
155	This allows you to either speed things up by keeping multiple images in	175	An expression can be "sensitive" to various external events, such as
156	memory, or comserve memory by loading images more often.	176	scaling or moving the window, root background changes and timers. Simply
		177	using an expression (such as C<scale> without parameters) that depends on
		178	certain changing values (called "variables"), or using those variables
		179	directly, will make an expression sensitive to these events - for example,
		180	using C<scale> or C<TW> will make the expression sensitive to the terminal
		181	size, and thus to resizing events.
157		182
158	For example, you can keep two images in memory and use a random one like	183	When such an event happens, C<keep> will automatically trigger a
159	this:	184	reevaluation of the whole expression with the new value of the expression.
160		185
161	my $img1 = load "img1.png";	186	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		187
165	Since both images are "loaded" every time the expression is evaluated,	188	rootalign once { blur 20, root }
166	they are always kept in memory. Contrast this version:
167		189
168	my $path1 = "img1.png";	190	This makes a blurred copy of the root background once, and on subsequent
169	my $path2 = "img2.png";	191	calls, just root-aligns it. Since C<blur> is usually quite slow and
170	load ((0.5 > rand) ? $path1 : $path2)	192	C<rootalign> is quite fast, this trades extra memory (for the cached
		193	blurred pixmap) with speed (blur only needs to be redone when root
		194	changes).
171		195
172	Here, a path is selected randomly, and load is only called for one image,	196	=head3 C<load> caching
173	so keeps only one image in memory. If, on the next evaluation, luck	197
174	decides to use the other path, then it will have to load that image again.	198	The C<load> operator itself does not keep images in memory, but as long as
		199	the image is still in memory, C<load> will use the in-memory image instead
		200	of loading it freshly from disk.
		201
		202	That means that this expression:
		203
		204	keep { load "$HOME/path..." }
		205
		206	Not only caches the image in memory, other terminal instances that try to
		207	C<load> it can reuse that in-memory copy.
175		208
176	=head1 REFERENCE	209	=head1 REFERENCE
177		210
178	=head2 COMMAND LINE SWITCHES	211	=head2 COMMAND LINE SWITCHES
179		212
…		…
189	overwriting borders and any other areas, such as the scrollbar.	222	overwriting borders and any other areas, such as the scrollbar.
190		223
191	Specifying this flag changes the behaviour, so that the image only	224	Specifying this flag changes the behaviour, so that the image only
192	replaces the background of the character area.	225	replaces the background of the character area.
193		226
		227	=item --background-interval seconds
		228
		229	Since some operations in the underlying XRender extension can effectively
		230	freeze your X-server for prolonged time, this extension enforces a minimum
		231	time between updates, which is normally about 0.1 seconds.
		232
		233	If you want to do updates more often, you can decrease this safety
		234	interval with this switch.
		235
194	=back	236	=back
195		237
196	=cut	238	=cut
197		239
		240	our %_IMG_CACHE;
198	our $HOME;	241	our $HOME;
199	our ($self, $old, $new);	242	our ($self, $frame);
200	our ($x, $y, $w, $h);	243	our ($x, $y, $w, $h);
201		244
202	# enforce at least this interval between updates	245	# enforce at least this interval between updates
203	our $MIN_INTERVAL = 1/100;	246	our $MIN_INTERVAL = 6/59.951;
204		247
205	{	248	{
206	package urxvt::bgdsl; # background language	249	package urxvt::bgdsl; # background language
		250
		251	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
		252	sub FR_CACHE () { 1 } # cached values
		253	sub FR_AGAIN () { 2 } # what this expr is sensitive to
		254	sub FR_STATE () { 3 } # watchers etc.
207		255
208	use List::Util qw(min max sum shuffle);	256	use List::Util qw(min max sum shuffle);
209		257
210	=head2 PROVIDERS/GENERATORS	258	=head2 PROVIDERS/GENERATORS
211		259
…		…
218	=item load $path	266	=item load $path
219		267
220	Loads the image at the given C<$path>. The image is set to plane tiling	268	Loads the image at the given C<$path>. The image is set to plane tiling
221	mode.	269	mode.
222		270
223	Loaded images will be cached for one cycle.	271	If the image is already in memory (e.g. because another terminal instance
		272	uses it), then the in-memory copy us returned instead.
224		273
		274	=item load_uc $path
		275
		276	Load uncached - same as load, but does not cache the image, which means it
		277	is I<always> loaded from the filesystem again.
		278
225	=cut	279	=cut
		280
		281	sub load_uc($) {
		282	$self->new_img_from_file ($path)
		283	}
226		284
227	sub load($) {	285	sub load($) {
228	my ($path) = @_;	286	my ($path) = @_;
229		287
230	$new->{load}{$path} = $old->{load}{$path} \|\| $self->new_img_from_file ($path);	288	$_IMG_CACHE{$path} \|\| do {
		289	my $img = load_uc $path;
		290	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		291	$img
		292	}
231	}	293	}
232		294
233	=item root	295	=item root
234		296
235	Returns the root window pixmap, that is, hopefully, the background image	297	Returns the root window pixmap, that is, hopefully, the background image
236	of your screen. The image is set to extend mode.	298	of your screen.
237		299
238	This function makes your expression root sensitive, that means it will be	300	This function makes your expression root sensitive, that means it will be
239	reevaluated when the bg image changes.	301	reevaluated when the bg image changes.
240		302
241	=cut	303	=cut
242		304
243	sub root() {	305	sub root() {
244	$new->{rootpmap_sensitive} = 1;	306	$frame->[FR_AGAIN]{rootpmap} = 1;
245	die "root op not supported, exg, we need you";	307	$self->new_img_from_root
246	}	308	}
247		309
248	=item solid $colour	310	=item solid $colour
249		311
250	=item solid $width, $height, $colour	312	=item solid $width, $height, $colour
…		…
258	=cut	320	=cut
259		321
260	sub solid($;$$) {	322	sub solid($;$$) {
261	my $colour = pop;	323	my $colour = pop;
262		324
263	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	325	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
264	$img->fill ($colour);	326	$img->fill ($colour);
265	$img	327	$img
266	}	328	}
267		329
268	=item clone $img	330	=item clone $img
…		…
274		336
275	sub clone($) {	337	sub clone($) {
276	$_[0]->clone	338	$_[0]->clone
277	}	339	}
278		340
279	=back	341	=item merge $img ...
		342
		343	Takes any number of images and merges them together, creating a single
		344	image containing them all. The tiling mode of the first image is used as
		345	the tiling mode of the resulting image.
		346
		347	This function is called automatically when an expression returns multiple
		348	images.
		349
		350	=cut
		351
		352	sub merge(@) {
		353	return $_[0] unless $#_;
		354
		355	# rather annoyingly clumsy, but optimisation is for another time
		356
		357	my $x0 = +1e9;
		358	my $y0 = +1e9;
		359	my $x1 = -1e9;
		360	my $y1 = -1e9;
		361
		362	for (@_) {
		363	my ($x, $y, $w, $h) = $_->geometry;
		364
		365	$x0 = $x if $x0 > $x;
		366	$y0 = $y if $y0 > $y;
		367
		368	$x += $w;
		369	$y += $h;
		370
		371	$x1 = $x if $x1 < $x;
		372	$y1 = $y if $y1 < $y;
		373	}
		374
		375	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		376	$base->repeat_mode ($_[0]->repeat_mode);
		377	$base->fill ([0, 0, 0, 0]);
		378
		379	$base->draw ($_)
		380	for @_;
		381
		382	$base
		383	}
280		384
281	=head2 TILING MODES	385	=head2 TILING MODES
282		386
283	The following operators modify the tiling mode of an image, that is, the	387	The following operators modify the tiling mode of an image, that is, the
284	way that pixels outside the image area are painted when the image is used.	388	way that pixels outside the image area are painted when the image is used.
…		…
314	become transparent. This mode is most useful when you want to place an	418	become transparent. This mode is most useful when you want to place an
315	image over another image or the background colour while leaving all	419	image over another image or the background colour while leaving all
316	background pixels outside the image unchanged.	420	background pixels outside the image unchanged.
317		421
318	Example: load an image and display it in the upper left corner. The rest	422	Example: load an image and display it in the upper left corner. The rest
319	of the space is left "empty" (transparent or wahtever your compisotr does	423	of the space is left "empty" (transparent or whatever your compositor does
320	in alpha mode, else background colour).	424	in alpha mode, else background colour).
321		425
322	pad load "mybg.png"	426	pad load "mybg.png"
323		427
324	=item extend $img	428	=item extend $img
325		429
326	Extends the image over the whole plane, using the closest pixel in the	430	Extends the image over the whole plane, using the closest pixel in the
327	area outside the image. This mode is mostly useful when you more complex	431	area outside the image. This mode is mostly useful when you use more complex
328	filtering operations and want the pixels outside the image to have the	432	filtering operations and want the pixels outside the image to have the
329	same values as the pixels near the edge.	433	same values as the pixels near the edge.
330		434
331	Example: just for curiosity, how does this pixel extension stuff work?	435	Example: just for curiosity, how does this pixel extension stuff work?
332		436
…		…
381	Using these functions make your expression sensitive to window moves.	485	Using these functions make your expression sensitive to window moves.
382		486
383	These functions are mainly useful to align images to the root window.	487	These functions are mainly useful to align images to the root window.
384		488
385	Example: load an image and align it so it looks as if anchored to the	489	Example: load an image and align it so it looks as if anchored to the
386	background.	490	background (that's exactly what C<rootalign> does btw.):
387		491
388	move -TX, -TY, load "mybg.png"	492	move -TX, -TY, keep { load "mybg.png" }
389		493
390	=item TW	494	=item TW
391		495
392	Return the width (C<TW>) and height (C<TH>) of the terminal window (the	496	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
393	terminal window is the full window by default, and the character area only	497	terminal window is the full window by default, and the character area only
…		…
399	the window size to conserve memory.	503	the window size to conserve memory.
400		504
401	Example: take the screen background, clip it to the window size, blur it a	505	Example: take the screen background, clip it to the window size, blur it a
402	bit, align it to the window position and use it as background.	506	bit, align it to the window position and use it as background.
403		507
404	clip move -TX, -TY, blur 5, root	508	clip move -TX, -TY, keep { blur 5, root }
405		509
406	=cut	510	=cut
407		511
408	sub TX() { $new->{position_sensitive} = 1; $x }	512	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
409	sub TY() { $new->{position_sensitive} = 1; $y }	513	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
410	sub TW() { $new->{size_sensitive} = 1; $w }	514	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
411	sub TH() { $new->{size_sensitive} = 1; $h }	515	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
412		516
413	=item now	517	=item now
414		518
415	Returns the current time as (fractional) seconds since the epoch.	519	Returns the current time as (fractional) seconds since the epoch.
416		520
…		…
423	C<$seconds> seconds.	527	C<$seconds> seconds.
424		528
425	Example: load some image and rotate it according to the time of day (as if it were	529	Example: load some image and rotate it according to the time of day (as if it were
426	the hour pointer of a clock). Update this image every minute.	530	the hour pointer of a clock). Update this image every minute.
427		531
		532	again 60;
428	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"	533	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
429		534
430	=item counter $seconds	535	=item counter $seconds
431		536
432	Like C<again>, but also returns an increasing counter value, starting at	537	Like C<again>, but also returns an increasing counter value, starting at
433	0, which might be useful for some simple animation effects.	538	0, which might be useful for some simple animation effects.
…		…
435	=cut	540	=cut
436		541
437	sub now() { urxvt::NOW }	542	sub now() { urxvt::NOW }
438		543
439	sub again($) {	544	sub again($) {
440	$new->{again} = $_[0];	545	$frame->[FR_AGAIN]{time} = $_[0];
441	}	546	}
442		547
443	sub counter($) {	548	sub counter($) {
444	$new->{again} = $_[0];	549	$frame->[FR_AGAIN]{time} = $_[0];
445	$self->{counter} + 0	550	$frame->[FR_STATE]{counter} + 0
446	}	551	}
447		552
448	=back	553	=back
449		554
450	=head2 SHAPE CHANGING OPERATORS	555	=head2 SHAPE CHANGING OPERATORS
…		…
470	assumed.	575	assumed.
471		576
472	Example: load an image, blur it, and clip it to the window size to save	577	Example: load an image, blur it, and clip it to the window size to save
473	memory.	578	memory.
474		579
475	clip blur 10, load "mybg.png"	580	clip keep { blur 10, load "mybg.png" }
476		581
477	=cut	582	=cut
478		583
479	sub clip($;$$;$$) {	584	sub clip($;$$;$$) {
480	my $img = pop;	585	my $img = pop;
…		…
553		658
554	Example: move the image right by 20 pixels and down by 30.	659	Example: move the image right by 20 pixels and down by 30.
555		660
556	move 20, 30, ...	661	move 20, 30, ...
557		662
		663	=item align $xalign, $yalign, $img
		664
		665	Aligns the image according to a factor - C<0> means the image is moved to
		666	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		667	exactly centered and C<1> means it touches the right or bottom edge.
		668
		669	Example: remove any visible border around an image, center it vertically but move
		670	it to the right hand side.
		671
		672	align 1, 0.5, pad $img
		673
558	=item center $img	674	=item center $img
559		675
560	=item center $width, $height, $img	676	=item center $width, $height, $img
561		677
562	Centers the image, i.e. the center of the image is moved to the center of	678	Centers the image, i.e. the center of the image is moved to the center of
563	the terminal window (or the box specified by C<$width> and C<$height> if	679	the terminal window (or the box specified by C<$width> and C<$height> if
564	given).	680	given).
		681
		682	Example: load an image and center it.
		683
		684	center keep { pad load "mybg.png" }
565		685
566	=item rootalign $img	686	=item rootalign $img
567		687
568	Moves the image so that it appears glued to the screen as opposed to the	688	Moves the image so that it appears glued to the screen as opposed to the
569	window. This gives the illusion of a larger area behind the window. It is	689	window. This gives the illusion of a larger area behind the window. It is
570	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	690	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
571	top left of the screen.	691	top left of the screen.
572		692
573	Example: load a background image, put it in mirror mode and root align it.	693	Example: load a background image, put it in mirror mode and root align it.
574		694
575	rootalign mirror load "mybg.png"	695	rootalign keep { mirror load "mybg.png" }
576		696
577	Example: take the screen background and align it, giving the illusion of	697	Example: take the screen background and align it, giving the illusion of
578	transparency as long as the window isn't in front of other windows.	698	transparency as long as the window isn't in front of other windows.
579		699
580	rootalign root	700	rootalign root
581		701
582	=cut	702	=cut
583		703
584	sub move($$;$) {	704	sub move($$;$) {
585	my $img = pop->clone;	705	my $img = pop->clone;
586	$img->move ($_[0], $_[1]);	706	$img->move ($_[0], $_[1]);
587	$img	707	$img
588	}	708	}
589		709
		710	sub align($;$$) {
		711	my $img = pop;
		712
		713	move $_[0] * (TW - $img->w),
		714	$_[1] * (TH - $img->h),
		715	$img
		716	}
		717
590	sub center($;$$) {	718	sub center($;$$) {
591	my $img = pop;	719	my $img = pop;
592	my $w = $_[0] \|\| TW;	720	my $w = $_[0] \|\| TW;
593	my $h = $_[0] \|\| TH;	721	my $h = $_[1] \|\| TH;
594		722
595	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img	723	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
596	}	724	}
597		725
598	sub rootalign($) {	726	sub rootalign($) {
599	move -TX, -TY, $_[0]	727	move -TX, -TY, $_[0]
		728	}
		729
		730	=item rotate $center_x, $center_y, $degrees, $img
		731
		732	Rotates the image clockwise by C<$degrees> degrees, around the point at
		733	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		734
		735	Example: rotate the image by 90 degrees around it's center.
		736
		737	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		738
		739	=cut
		740
		741	sub rotate($$$$) {
		742	my $img = pop;
		743	$img->rotate (
		744	$_[0] * ($img->w + $img->x),
		745	$_[1] * ($img->h + $img->y),
		746	$_[2] * (3.14159265 / 180),
		747	)
600	}	748	}
601		749
602	=back	750	=back
603		751
604	=head2 COLOUR MODIFICATIONS	752	=head2 COLOUR MODIFICATIONS
…		…
640		788
641	Values less than 0 reduce brightness, while values larger than 0 increase	789	Values less than 0 reduce brightness, while values larger than 0 increase
642	it. Useful range is from -1 to 1 - the former results in a black, the	790	it. Useful range is from -1 to 1 - the former results in a black, the
643	latter in a white picture.	791	latter in a white picture.
644		792
645	Due to idiosynchrasies in the underlying XRender extension, biases less	793	Due to idiosyncrasies in the underlying XRender extension, biases less
646	than zero can be I<very> slow.	794	than zero can be I<very> slow.
647		795
648	=cut	796	=cut
649		797
650	sub contrast($$;$$;$) {	798	sub contrast($$;$$;$) {
651	my $img = pop;	799	my $img = pop;
652	my ($r, $g, $b, $a) = @_;	800	my ($r, $g, $b, $a) = @_;
653		801
654	($g, $b) = ($r, $r) if @_ < 4;	802	($g, $b) = ($r, $r) if @_ < 3;
655	$a = 1 if @_ < 5;	803	$a = 1 if @_ < 4;
656		804
657	$img = $img->clone;	805	$img = $img->clone;
658	$img->contrast ($r, $g, $b, $a);	806	$img->contrast ($r, $g, $b, $a);
659	$img	807	$img
660	}	808	}
661		809
662	sub brightness($$;$$;$) {	810	sub brightness($$;$$;$) {
663	my $img = pop;	811	my $img = pop;
664	my ($r, $g, $b, $a) = @_;	812	my ($r, $g, $b, $a) = @_;
665		813
666	($g, $b) = ($r, $r) if @_ < 4;	814	($g, $b) = ($r, $r) if @_ < 3;
667	$a = 1 if @_ < 5;	815	$a = 1 if @_ < 4;
668		816
669	$img = $img->clone;	817	$img = $img->clone;
670	$img->brightness ($r, $g, $b, $a);	818	$img->brightness ($r, $g, $b, $a);
671	$img	819	$img
672	}	820	}
…		…
688	sub blur($$;$) {	836	sub blur($$;$) {
689	my $img = pop;	837	my $img = pop;
690	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	838	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
691	}	839	}
692		840
693	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
694
695	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
696	pointer at C<$center_x> and C<$center_y> (specified as factor of image
697	width/height), generating a new image with width C<$new_width> and height
698	C<$new_height>.
699
700	#TODO# new width, height, maybe more operators?
701
702	Example: rotate the image by 90 degrees
703
704	=cut
705
706	sub rotate($$$$$$) {
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	841	=back
718		842
		843	=head2 OTHER STUFF
		844
		845	Anything that didn't fit any of the other categories, even after applying
		846	force and closing our eyes.
		847
		848	=over 4
		849
		850	=item keep { ... }
		851
		852	#TODO#
		853
		854	This operator takes a code block as argument, that is, one or more
		855	statements enclosed by braces.
		856
		857	The trick is that this code block is only evaluated once - future calls
		858	will simply return the original image (yes, it should only be used with
		859	images).
		860
		861	This can be extremely useful to avoid redoing the same slow operations
		862	again and again- for example, if your background expression takes the root
		863	background, blurs it and then root-aligns it it would have to blur the
		864	root background on every window move or resize.
		865
		866	In fact, urxvt itself encloses the whole expression in some kind of
		867	C<once> block so it only is reevaluated as required.
		868
		869	Putting the blur into a C<once> block will make sure the blur is only done
		870	once:
		871
		872	rootlign keep { blur 10, root }
		873
		874	This leaves the question of how to force reevaluation of the block,
		875	in case the root background changes: If expression inside the block
		876	is sensitive to some event (root background changes, window geometry
		877	changes), then it will be reevaluated automatically as needed.
		878
		879	=item once_again
		880
		881	Resets all C<once> block as if they had never been called, i.e. on the
		882	next call they will be reevaluated again.
		883
		884	=cut
		885
		886	sub once(&) {
		887	my $id = $_[0]+0;
		888
		889	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		890
		891	unless ($frame->[FR_CACHE]) {
		892	$frame->[FR_CACHE] = [ $_[0]() ];
		893
		894	my $self = $self;
		895	my $frame = $frame;
		896	Scalar::Util::weaken $frame;
		897	$self->compile_frame ($frame, sub {
		898	# clear this frame cache, also for all parents
		899	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		900	undef $frame->[FR_CACHE];
		901	}
		902
		903	$self->recalculate;
		904	});
		905	};
		906
		907	# in scalar context we always return the first original result, which
		908	# is not quite how perl works.
		909	wantarray
		910	? @{ $frame->[FR_CACHE] }
		911	: $frame->[FR_CACHE][0]
		912	}
		913
		914	sub once_again() {
		915	delete $self->{frame_cache};
		916	}
		917
		918	=back
		919
719	=cut	920	=cut
720		921
721	}	922	}
722		923
723	sub parse_expr {	924	sub parse_expr {
724	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	925	my $expr = eval
		926	"sub {\n"
		927	. "package urxvt::bgdsl;\n"
		928	. "#line 0 'background expression'\n"
		929	. "$_[0]\n"
		930	. "}";
725	die if $@;	931	die if $@;
726	$expr	932	$expr
727	}	933	}
728		934
729	# compiles a parsed expression	935	# compiles a parsed expression
730	sub set_expr {	936	sub set_expr {
731	my ($self, $expr) = @_;	937	my ($self, $expr) = @_;
732		938
		939	$self->{root} = [];
733	$self->{expr} = $expr;	940	$self->{expr} = $expr;
734	$self->recalculate;	941	$self->recalculate;
		942	}
		943
		944	# takes a hash of sensitivity indicators and installs watchers
		945	sub compile_frame {
		946	my ($self, $frame, $cb) = @_;
		947
		948	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		949	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		950
		951	# don't keep stuff alive
		952	Scalar::Util::weaken $state;
		953
		954	if ($again->{nested}) {
		955	$state->{nested} = 1;
		956	} else {
		957	delete $state->{nested};
		958	}
		959
		960	if (my $interval = $again->{time}) {
		961	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		962	if $state->{time}[0] != $interval;
		963
		964	# callback might have changed, although we could just rule that out
		965	$state->{time}[1]->cb (sub {
		966	++$state->{counter};
		967	$cb->();
		968	});
		969	} else {
		970	delete $state->{time};
		971	}
		972
		973	if ($again->{position}) {
		974	$state->{position} = $self->on (position_change => $cb);
		975	} else {
		976	delete $state->{position};
		977	}
		978
		979	if ($again->{size}) {
		980	$state->{size} = $self->on (size_change => $cb);
		981	} else {
		982	delete $state->{size};
		983	}
		984
		985	if ($again->{rootpmap}) {
		986	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		987	} else {
		988	delete $state->{rootpmap};
		989	}
735	}	990	}
736		991
737	# evaluate the current bg expression	992	# evaluate the current bg expression
738	sub recalculate {	993	sub recalculate {
739	my ($arg_self) = @_;	994	my ($arg_self) = @_;
…		…
749		1004
750	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1005	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
751		1006
752	# set environment to evaluate user expression	1007	# set environment to evaluate user expression
753		1008
754	local $self = $arg_self;	1009	local $self = $arg_self;
755
756	local $HOME = $ENV{HOME};	1010	local $HOME = $ENV{HOME};
757	local $old = $self->{state};	1011	local $frame = [];
758	local $new = my $state = $self->{state} = {};
759		1012
760	($x, $y, $w, $h) =
761	$self->background_geometry ($self->{border});	1013	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
762		1014
763	# evaluate user expression	1015	# evaluate user expression
764		1016
765	my $img = eval { $self->{expr}->() };	1017	my @img = eval { $self->{expr}->() };
766	warn $@ if $@;#d#	1018	die $@ if $@;
		1019	die "background-expr did not return anything.\n" unless @img;
		1020	die "background-expr: expected image(s), got something else.\n"
767	die if !UNIVERSAL::isa $img, "urxvt::img";	1021	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
768		1022
769	$state->{size_sensitive} = 1	1023	my $img = urxvt::bgdsl::merge @img;
		1024
		1025	$frame->[FR_AGAIN]{size} = 1
770	if $img->repeat_mode != urxvt::RepeatNormal;	1026	if $img->repeat_mode != urxvt::RepeatNormal;
771		1027
772	# if the expression is sensitive to external events, prepare reevaluation then	1028	# if the expression is sensitive to external events, prepare reevaluation then
773		1029	$self->compile_frame ($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	$self->disable ("rootpmap_change");
806	}
807		1030
808	# clear stuff we no longer need	1031	# clear stuff we no longer need
809		1032
810	%$old = ();	1033	# unless (%{ $frame->[FR_STATE] }) {
811
812	unless ($repeat) {
813	delete $self->{state};	1034	# delete $self->{state};
814	delete $self->{expr};	1035	# delete $self->{expr};
815	}	1036	# }
816		1037
817	# set background pixmap	1038	# set background pixmap
818		1039
819	$self->set_background ($img, $self->{border});	1040	$self->set_background ($img, $self->{border});
820	$self->scr_recolour (0);	1041	$self->scr_recolour (0);
…		…
822	}	1043	}
823		1044
824	sub on_start {	1045	sub on_start {
825	my ($self) = @_;	1046	my ($self) = @_;
826		1047
827	my $expr = $self->x_resource ("background.expr")	1048	my $expr = $self->x_resource ("%.expr")
828	or return;	1049	or return;
829		1050
		1051	$self->has_render
		1052	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1053
830	$self->set_expr (parse_expr $expr);	1054	$self->set_expr (parse_expr $expr);
831	$self->{border} = $self->x_resource_boolean ("background.border");	1055	$self->{border} = $self->x_resource_boolean ("%.border");
		1056
		1057	$MIN_INTERVAL = $self->x_resource ("%.interval");
832		1058
833	()	1059	()
834	}	1060	}
835		1061

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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 1.67 by sf-exg, Fri Jun 29 18:12:25 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 1.67 by sf-exg, Fri Jun 29 18:12:25 2012 UTC