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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.8 by root, Tue Jun 5 14:07:47 2012 UTC vs.
Revision 1.71 by root, Mon Jul 2 01:40:41 2012 UTC

1	#! perl	1	#! perl
2		2
3	our $EXPR = 'move load "/root/pix/das_fette_schwein.jpg", repeat_wrap, X, Y';	3	#:META:X_RESOURCE:%.expr:string:background expression
4	$EXPR = '	4	#:META:X_RESOURCE:%.border:boolean:respect the terminal border
5	blur 10, 10,	5	#:META:X_RESOURCE:%.interval:seconds:minimum time between updates
6	rotate W, H, 50, 50, counter 1/60, repeat_mirror,
7	clip X, Y, W, H, repeat_mirror,
8	load "/root/pix/das_fette_schwein.jpg"
9	';
10	#$EXPR = 'blur root, 10, 10'
11	#$EXPR = 'blur move (root, -x, -y), 5, 5'
12	#resize load "/root/pix/das_fette_schwein.jpg", w, h
13		6
14	use Safe;	7	=head1 NAME
15		8
16	our ($bgdsl_self, $old, $new);	9	background - manage terminal background
		10
		11	=head1 SYNOPSIS
		12
		13	urxvt --background-expr 'background expression'
		14	--background-border
		15	--background-interval seconds
		16
		17	=head1 DESCRIPTION
		18
		19	This extension manages the terminal background by creating a picture that
		20	is behind the text, replacing the normal background colour.
		21
		22	It does so by evaluating a Perl expression that I<calculates> the image on
		23	the fly, for example, by grabbing the root background or loading a file.
		24
		25	While the full power of Perl is available, the operators have been design
		26	to be as simple as possible.
		27
		28	For example, to load an image and scale it to the window size, you would
		29	use:
		30
		31	urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
		32
		33	Or specified as a X resource:
		34
		35	URxvt.background-expr: scale keep { load "/path/to/mybg.png" }
		36
		37	=head1 THEORY OF OPERATION
		38
		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
		41	extended as necessary to cover the whole terminal window, and is set as a
		42	background pixmap.
		43
		44	If the image contains an alpha channel, then it will be used as-is in
		45	visuals that support alpha channels (for example, for a compositing
		46	manager). In other visuals, the terminal background colour will be used to
		47	replace any transparency.
		48
		49	When the expression relies, directly or indirectly, on the window size,
		50	position, the root pixmap, or a timer, then it will be remembered. If not,
		51	then it will be removed.
		52
		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
		55	pixmap is replaced by another one the root background changes; or when the
		56	timer elapses), then the expression will be evaluated again.
		57
		58	For example, an expression such as C<scale keep { load "$HOME/mybg.png"
		59	}> scales the image to the window size, so it relies on the window size
		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
		62	after its size changes.
		63
		64	=head2 EXPRESSIONS
		65
		66	Expressions are normal Perl expressions, in fact, they are Perl blocks -
		67	which means you could use multiple lines and statements:
		68
		69	scale keep {
		70	again 3600;
		71	if (localtime now)[6]) {
		72	return load "$HOME/weekday.png";
		73	} else {
		74	return load "$HOME/sunday.png";
		75	}
		76	}
		77
		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
		80	Sundays, and F<weekday.png> on all other days.
		81
		82	Fortunately, we expect that most expressions will be much simpler, with
		83	little Perl knowledge needed.
		84
		85	Basically, you always start with a function that "generates" an image
		86	object, such as C<load>, which loads an image from disk, or C<root>, which
		87	returns the root window background image:
		88
		89	load "$HOME/mypic.png"
		90
		91	The path is usually specified as a quoted string (the exact rules can be
		92	found in the L<perlop> manpage). The F<$HOME> at the beginning of the
		93	string is expanded to the home directory.
		94
		95	Then you prepend one or more modifiers or filtering expressions, such as
		96	C<scale>:
		97
		98	scale load "$HOME/mypic.png"
		99
		100	Just like a mathematical expression with functions, you should read these
		101	expressions from right to left, as the C<load> is evaluated first, and
		102	its result becomes the argument to the C<scale> function.
		103
		104	Many operators also allow some parameters preceding the input image
		105	that modify its behaviour. For example, C<scale> without any additional
		106	arguments scales the image to size of the terminal window. If you specify
		107	an additional argument, it uses it as a scale factor (multiply by 100 to
		108	get a percentage):
		109
		110	scale 2, load "$HOME/mypic.png"
		111
		112	This enlarges the image by a factor of 2 (200%). As you can see, C<scale>
		113	has now two arguments, the C<200> and the C<load> expression, while
		114	C<load> only has one argument. Arguments are separated from each other by
		115	commas.
		116
		117	Scale also accepts two arguments, which are then separate factors for both
		118	horizontal and vertical dimensions. For example, this halves the image
		119	width and doubles the image height:
		120
		121	scale 0.5, 2, load "$HOME/mypic.png"
		122
		123	IF you try out these expressions, you might suffer from some sluggishness,
		124	because each time the terminal is resized, it loads the PNG image agin
		125	and scales it. Scaling is usually fast (and unavoidable), but loading the
		126	image can be quite time consuming. This is where C<keep> comes in handy:
		127
		128	scale 0.5, 2, keep { load "$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
		143	tile keep { load "$HOME/mypic.png" }
		144
		145	In fact, images returned by C<load> are in C<tile> mode by default, so the
		146	C<tile> operator is kind of superfluous.
		147
		148	Another common effect is to mirror the image, so that the same edges
		149	touch:
		150
		151	mirror keep { load "$HOME/mypic.png" }
		152
		153	Another common background expression is:
		154
		155	rootalign root
		156
		157	This one first takes a snapshot of the screen background image, and then
		158	moves it to the upper left corner of the screen (as opposed to the upper
		159	left corner of the terminal window)- the result is pseudo-transparency:
		160	the image seems to be static while the window is moved around.
		161
		162	=head2 COLOUR SPECIFICATIONS
		163
		164	Whenever an oprator expects a "colour", then this can be specified in one
		165	of two ways: Either as string with an X11 colour specification, such as:
		166
		167	"red" # named colour
		168	"#f00" # simple rgb
		169	"[50]red" # red with 50% alpha
		170	"TekHVC:300/50/50" # anything goes
		171
		172	OR as an array reference with one, three or four components:
		173
		174	[0.5] # 50% gray, 100% alpha
		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
		177
		178	=head2 CACHING AND SENSITIVITY
		179
		180	Since some operations (such as C<load> and C<blur>) can take a long time,
		181	caching results can be very important for a smooth operation. Caching can
		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.
		185
		186	=head3 C<keep { ... }> caching
		187
		188	The most important way to cache expensive operations is to use C<keep {
		189	... }>. The C<keep> operator takes a block of multiple statements enclosed
		190	by C<{}> and keeps the return value in memory.
		191
		192	An expression can be "sensitive" to various external events, such as
		193	scaling or moving the window, root background changes and timers. Simply
		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.
		225
		226	=head1 REFERENCE
		227
		228	=head2 COMMAND LINE SWITCHES
		229
		230	=over 4
		231
		232	=item --background-expr perl-expression
		233
		234	Specifies the Perl expression to evaluate.
		235
		236	=item --background-border
		237
		238	By default, the expression creates an image that fills the full window,
		239	overwriting borders and any other areas, such as the scrollbar.
		240
		241	Specifying this flag changes the behaviour, so that the image only
		242	replaces the background of the character area.
		243
		244	=item --background-interval seconds
		245
		246	Since some operations in the underlying XRender extension can effectively
		247	freeze your X-server for prolonged time, this extension enforces a minimum
		248	time between updates, which is normally about 0.1 seconds.
		249
		250	If you want to do updates more often, you can decrease this safety
		251	interval with this switch.
		252
		253	=back
		254
		255	=cut
		256
		257	our %_IMG_CACHE;
		258	our $HOME;
		259	our ($self, $frame);
17	our ($l, $t, $w, $h);	260	our ($x, $y, $w, $h);
		261
		262	# enforce at least this interval between updates
		263	our $MIN_INTERVAL = 6/59.951;
18		264
19	{	265	{
20	package urxvt::bgdsl; # background language	266	package urxvt::bgdsl; # background language
21		267
22	*repeat_black = \&urxvt::RepeatNone; #TODO wtf	268	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
23	*repeat_wrap = \&urxvt::RepeatNormal;	269	sub FR_CACHE () { 1 } # cached values
24	*repeat_pad = \&urxvt::RepeatPad;	270	sub FR_AGAIN () { 2 } # what this expr is sensitive to
25	*repeat_mirror = \&urxvt::RepeatReflect;	271	sub FR_STATE () { 3 } # watchers etc.
		272
		273	use List::Util qw(min max sum shuffle);
		274
		275	=head2 PROVIDERS/GENERATORS
		276
		277	These functions provide an image, by loading it from disk, grabbing it
		278	from the root screen or by simply generating it. They are used as starting
		279	points to get an image you can play with.
		280
		281	=over 4
		282
		283	=item load $path
		284
		285	Loads the image at the given C<$path>. The image is set to plane tiling
		286	mode.
		287
		288	If the image is already in memory (e.g. because another terminal instance
		289	uses it), then the in-memory copy us returned instead.
		290
		291	=item load_uc $path
		292
		293	Load uncached - same as load, but does not cache the image, which means it
		294	is I<always> loaded from the filesystem again.
		295
		296	=cut
26		297
27	sub load($) {	298	sub load($) {
28	my ($path) = @_;	299	my ($path) = @_;
29		300
30	$new->{load}{$path} = $old->{load}{$path} \|\| $bgdsl_self->new_img_from_file ($path);	301	$_IMG_CACHE{$path} \|\| do {
		302	my $img = $self->new_img_from_file ($path);
		303	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		304	$img
		305	}
31	}	306	}
		307
		308	=item root
		309
		310	Returns the root window pixmap, that is, hopefully, the background image
		311	of your screen.
		312
		313	This function makes your expression root sensitive, that means it will be
		314	reevaluated when the bg image changes.
		315
		316	=cut
32		317
33	sub root() {	318	sub root() {
34	die "root op not supported, exg, we need you";	319	$frame->[FR_AGAIN]{rootpmap} = 1;
		320	$self->new_img_from_root
35	}	321	}
36		322
		323	=item solid $colour
		324
		325	=item solid $width, $height, $colour
		326
		327	Creates a new image and completely fills it with the given colour. The
		328	image is set to tiling mode.
		329
		330	If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
		331	useful for solid backgrounds or for use in filtering effects.
		332
		333	=cut
		334
		335	sub solid($;$$) {
		336	my $colour = pop;
		337
		338	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
		339	$img->fill ($colour);
		340	$img
		341	}
		342
		343	=item clone $img
		344
		345	Returns an exact copy of the image. This is useful if you want to have
		346	multiple copies of the same image to apply different effects to.
		347
		348	=cut
		349
37	# sub clone($) {	350	sub clone($) {
38	# $_[0]->clone	351	$_[0]->clone
39	# }	352	}
40		353
		354	=item merge $img ...
		355
		356	Takes any number of images and merges them together, creating a single
		357	image containing them all. The tiling mode of the first image is used as
		358	the tiling mode of the resulting image.
		359
		360	This function is called automatically when an expression returns multiple
		361	images.
		362
		363	=cut
		364
		365	sub merge(@) {
		366	return $_[0] unless $#_;
		367
		368	# rather annoyingly clumsy, but optimisation is for another time
		369
		370	my $x0 = +1e9;
		371	my $y0 = +1e9;
		372	my $x1 = -1e9;
		373	my $y1 = -1e9;
		374
		375	for (@_) {
		376	my ($x, $y, $w, $h) = $_->geometry;
		377
		378	$x0 = $x if $x0 > $x;
		379	$y0 = $y if $y0 > $y;
		380
		381	$x += $w;
		382	$y += $h;
		383
		384	$x1 = $x if $x1 < $x;
		385	$y1 = $y if $y1 < $y;
		386	}
		387
		388	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		389	$base->repeat_mode ($_[0]->repeat_mode);
		390	$base->fill ([0, 0, 0, 0]);
		391
		392	$base->draw ($_)
		393	for @_;
		394
		395	$base
		396	}
		397
		398	=head2 TILING MODES
		399
		400	The following operators modify the tiling mode of an image, that is, the
		401	way that pixels outside the image area are painted when the image is used.
		402
		403	=over 4
		404
		405	=item tile $img
		406
		407	Tiles the whole plane with the image and returns this new image - or in
		408	other words, it returns a copy of the image in plane tiling mode.
		409
		410	Example: load an image and tile it over the background, without
		411	resizing. The C<tile> call is superfluous because C<load> already defaults
		412	to tiling mode.
		413
		414	tile load "mybg.png"
		415
		416	=item mirror $img
		417
		418	Similar to tile, but reflects the image each time it uses a new copy, so
		419	that top edges always touch top edges, right edges always touch right
		420	edges and so on (with normal tiling, left edges always touch right edges
		421	and top always touch bottom edges).
		422
		423	Example: load an image and mirror it over the background, avoiding sharp
		424	edges at the image borders at the expense of mirroring the image itself
		425
		426	mirror load "mybg.png"
		427
		428	=item pad $img
		429
		430	Takes an image and modifies it so that all pixels outside the image area
		431	become transparent. This mode is most useful when you want to place an
		432	image over another image or the background colour while leaving all
		433	background pixels outside the image unchanged.
		434
		435	Example: load an image and display it in the upper left corner. The rest
		436	of the space is left "empty" (transparent or whatever your compositor does
		437	in alpha mode, else background colour).
		438
		439	pad load "mybg.png"
		440
		441	=item extend $img
		442
		443	Extends the image over the whole plane, using the closest pixel in the
		444	area outside the image. This mode is mostly useful when you use more complex
		445	filtering operations and want the pixels outside the image to have the
		446	same values as the pixels near the edge.
		447
		448	Example: just for curiosity, how does this pixel extension stuff work?
		449
		450	extend move 50, 50, load "mybg.png"
		451
		452	=cut
		453
		454	sub pad($) {
		455	my $img = $_[0]->clone;
		456	$img->repeat_mode (urxvt::RepeatNone);
		457	$img
		458	}
		459
		460	sub tile($) {
		461	my $img = $_[0]->clone;
		462	$img->repeat_mode (urxvt::RepeatNormal);
		463	$img
		464	}
		465
		466	sub mirror($) {
		467	my $img = $_[0]->clone;
		468	$img->repeat_mode (urxvt::RepeatReflect);
		469	$img
		470	}
		471
		472	sub extend($) {
		473	my $img = $_[0]->clone;
		474	$img->repeat_mode (urxvt::RepeatPad);
		475	$img
		476	}
		477
		478	=back
		479
		480	=head2 VARIABLE VALUES
		481
		482	The following functions provide variable data such as the terminal window
		483	dimensions. They are not (Perl-) variables, they just return stuff that
		484	varies. Most of them make your expression sensitive to some events, for
		485	example using C<TW> (terminal width) means your expression is evaluated
		486	again when the terminal is resized.
		487
		488	=over 4
		489
		490	=item TX
		491
		492	=item TY
		493
		494	Return the X and Y coordinates of the terminal window (the terminal
		495	window is the full window by default, and the character area only when in
		496	border-respect mode).
		497
		498	Using these functions make your expression sensitive to window moves.
		499
		500	These functions are mainly useful to align images to the root window.
		501
		502	Example: load an image and align it so it looks as if anchored to the
		503	background (that's exactly what C<rootalign> does btw.):
		504
		505	move -TX, -TY, keep { load "mybg.png" }
		506
		507	=item TW
		508
		509	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		510	terminal window is the full window by default, and the character area only
		511	when in border-respect mode).
		512
		513	Using these functions make your expression sensitive to window resizes.
		514
		515	These functions are mainly useful to scale images, or to clip images to
		516	the window size to conserve memory.
		517
		518	Example: take the screen background, clip it to the window size, blur it a
		519	bit, align it to the window position and use it as background.
		520
		521	clip move -TX, -TY, keep { blur 5, root }
		522
		523	=cut
		524
		525	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
		526	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
		527	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
		528	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
		529
		530	=item now
		531
		532	Returns the current time as (fractional) seconds since the epoch.
		533
		534	Using this expression does I<not> make your expression sensitive to time,
		535	but the next two functions do.
		536
		537	=item again $seconds
		538
		539	When this function is used the expression will be reevaluated again in
		540	C<$seconds> seconds.
		541
		542	Example: load some image and rotate it according to the time of day (as if it were
		543	the hour pointer of a clock). Update this image every minute.
		544
		545	again 60;
		546	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
		547
		548	=item counter $seconds
		549
		550	Like C<again>, but also returns an increasing counter value, starting at
		551	0, which might be useful for some simple animation effects.
		552
		553	=cut
		554
		555	sub now() { urxvt::NOW }
		556
		557	sub again($) {
		558	$frame->[FR_AGAIN]{time} = $_[0];
		559	}
		560
		561	sub counter($) {
		562	$frame->[FR_AGAIN]{time} = $_[0];
		563	$frame->[FR_STATE]{counter} + 0
		564	}
		565
		566	=back
		567
		568	=head2 SHAPE CHANGING OPERATORS
		569
		570	The following operators modify the shape, size or position of the image.
		571
		572	=over 4
		573
		574	=item clip $img
		575
		576	=item clip $width, $height, $img
		577
		578	=item clip $x, $y, $width, $height, $img
		579
		580	Clips an image to the given rectangle. If the rectangle is outside the
		581	image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is
		582	larger than the image, then the tiling mode defines how the extra pixels
		583	will be filled.
		584
		585	If C<$x> an C<$y> are missing, then C<0> is assumed for both.
		586
		587	If C<$width> and C<$height> are missing, then the window size will be
		588	assumed.
		589
		590	Example: load an image, blur it, and clip it to the window size to save
		591	memory.
		592
		593	clip keep { blur 10, load "mybg.png" }
		594
		595	=cut
		596
41	sub clip($$$$$;$) {	597	sub clip($;$$;$$) {
42	my $img = pop;	598	my $img = pop;
		599	my $h = pop \|\| TH;
		600	my $w = pop \|\| TW;
43	$img->sub_rect ($_[0], $_[1], $_[2], $_[3], $_[4])	601	$img->sub_rect ($_[0], $_[1], $w, $h)
		602	}
		603
		604	=item scale $img
		605
		606	=item scale $size_factor, $img
		607
		608	=item scale $width_factor, $height_factor, $img
		609
		610	Scales the image by the given factors in horizontal
		611	(C<$width>) and vertical (C<$height>) direction.
		612
		613	If only one factor is give, it is used for both directions.
		614
		615	If no factors are given, scales the image to the window size without
		616	keeping aspect.
		617
		618	=item resize $width, $height, $img
		619
		620	Resizes the image to exactly C<$width> times C<$height> pixels.
		621
		622	=item fit $img
		623
		624	=item fit $width, $height, $img
		625
		626	Fits the image into the given C<$width> and C<$height> without changing
		627	aspect, or the terminal size. That means it will be shrunk or grown until
		628	the whole image fits into the given area, possibly leaving borders.
		629
		630	=item cover $img
		631
		632	=item cover $width, $height, $img
		633
		634	Similar to C<fit>, but shrinks or grows until all of the area is covered
		635	by the image, so instead of potentially leaving borders, it will cut off
		636	image data that doesn't fit.
		637
		638	=cut
		639
		640	sub scale($;$;$) {
		641	my $img = pop;
		642
		643	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
		644	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
		645	: $img->scale (TW, TH)
44	}	646	}
45		647
46	sub resize($$$) {	648	sub resize($$$) {
47	my $img = pop;	649	my $img = pop;
48	$img->scale ($_[0], $_[1])	650	$img->scale ($_[0], $_[1])
49	}	651	}
50		652
51	# TODO: ugly	653	sub fit($;$$) {
		654	my $img = pop;
		655	my $w = ($_[0] \|\| TW) / $img->w;
		656	my $h = ($_[1] \|\| TH) / $img->h;
		657	scale +(min $w, $h), $img
		658	}
		659
		660	sub cover($;$$) {
		661	my $img = pop;
		662	my $w = ($_[0] \|\| TW) / $img->w;
		663	my $h = ($_[1] \|\| TH) / $img->h;
		664	scale +(max $w, $h), $img
		665	}
		666
		667	=item move $dx, $dy, $img
		668
		669	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
		670	the vertical.
		671
		672	Example: move the image right by 20 pixels and down by 30.
		673
		674	move 20, 30, ...
		675
		676	=item align $xalign, $yalign, $img
		677
		678	Aligns the image according to a factor - C<0> means the image is moved to
		679	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		680	exactly centered and C<1> means it touches the right or bottom edge.
		681
		682	Example: remove any visible border around an image, center it vertically but move
		683	it to the right hand side.
		684
		685	align 1, 0.5, pad $img
		686
		687	=item center $img
		688
		689	=item center $width, $height, $img
		690
		691	Centers the image, i.e. the center of the image is moved to the center of
		692	the terminal window (or the box specified by C<$width> and C<$height> if
		693	given).
		694
		695	Example: load an image and center it.
		696
		697	center keep { pad load "mybg.png" }
		698
		699	=item rootalign $img
		700
		701	Moves the image so that it appears glued to the screen as opposed to the
		702	window. This gives the illusion of a larger area behind the window. It is
		703	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
		704	top left of the screen.
		705
		706	Example: load a background image, put it in mirror mode and root align it.
		707
		708	rootalign keep { mirror load "mybg.png" }
		709
		710	Example: take the screen background and align it, giving the illusion of
		711	transparency as long as the window isn't in front of other windows.
		712
		713	rootalign root
		714
		715	=cut
		716
52	sub move($$;$) {	717	sub move($$;$) {
		718	my $img = pop->clone;
		719	$img->move ($_[0], $_[1]);
		720	$img
		721	}
		722
		723	sub align($;$$) {
53	my $img = pop;	724	my $img = pop;
54	$img->sub_rect (
55	$_[0], $_[1],
56	$img->w, $img->h,
57	$_[2],
58	)
59	}
60		725
		726	move $_[0] * (TW - $img->w),
		727	$_[1] * (TH - $img->h),
		728	$img
		729	}
		730
		731	sub center($;$$) {
		732	my $img = pop;
		733	my $w = $_[0] \|\| TW;
		734	my $h = $_[1] \|\| TH;
		735
		736	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		737	}
		738
		739	sub rootalign($) {
		740	move -TX, -TY, $_[0]
		741	}
		742
		743	=item rotate $center_x, $center_y, $degrees, $img
		744
		745	Rotates the image clockwise by C<$degrees> degrees, around the point at
		746	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		747
		748	Example: rotate the image by 90 degrees around it's center.
		749
		750	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		751
		752	=cut
		753
61	sub rotate($$$$$$;$) {	754	sub rotate($$$$) {
62	my $img = pop;	755	my $img = pop;
63	$img->rotate (	756	$img->rotate (
64	$_[0],	757	$_[0] * ($img->w + $img->x),
65	$_[1],	758	$_[1] * ($img->h + $img->y),
66	$_[2] * $img->w * .01,
67	$_[3] * $img->h * .01,
68	$_[4] * (3.14159265 / 180),	759	$_[2] * (3.14159265 / 180),
69	$_[5],
70	)	760	)
71	}	761	}
72		762
73	sub blur($$$) {	763	=back
74	my ($rh, $rv, $img) = @_;
75		764
76	$img = $img->clone;	765	=head2 COLOUR MODIFICATIONS
77	$img->blur ($rh, $rv);	766
78	$img	767	The following operators change the pixels of the image.
		768
		769	=over 4
		770
		771	=item tint $color, $img
		772
		773	Tints the image in the given colour.
		774
		775	Example: tint the image red.
		776
		777	tint "red", load "rgb.png"
		778
		779	Example: the same, but specify the colour by component.
		780
		781	tint [1, 0, 0], load "rgb.png"
		782
		783	=cut
		784
		785	sub tint($$) {
		786	$_[1]->tint ($_[0])
79	}	787	}
		788
		789	=item contrast $factor, $img
		790
		791	=item contrast $r, $g, $b, $img
		792
		793	=item contrast $r, $g, $b, $a, $img
		794
		795	Adjusts the I<contrast> of an image.
		796
		797	The first form applies a single C<$factor> to red, green and blue, the
		798	second form applies separate factors to each colour channel, and the last
		799	form includes the alpha channel.
		800
		801	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		802	contrast.
		803
		804	Due to limitations in the underlying XRender extension, lowering contrast
		805	also reduces brightness, while increasing contrast currently also
		806	increases brightness.
		807
		808	=item brightness $bias, $img
		809
		810	=item brightness $r, $g, $b, $img
		811
		812	=item brightness $r, $g, $b, $a, $img
		813
		814	Adjusts the brightness of an image.
		815
		816	The first form applies a single C<$bias> to red, green and blue, the
		817	second form applies separate biases to each colour channel, and the last
		818	form includes the alpha channel.
		819
		820	Values less than 0 reduce brightness, while values larger than 0 increase
		821	it. Useful range is from -1 to 1 - the former results in a black, the
		822	latter in a white picture.
		823
		824	Due to idiosyncrasies in the underlying XRender extension, biases less
		825	than zero can be I<very> slow.
		826
		827	=cut
80		828
81	sub contrast($$;$$;$) {	829	sub contrast($$;$$;$) {
82	my $img = pop;	830	my $img = pop;
83	my ($r, $g, $b, $a) = @_;	831	my ($r, $g, $b, $a) = @_;
84		832
85	($g, $b) = ($r, $r) if @_ < 4;	833	($g, $b) = ($r, $r) if @_ < 3;
86	$a = 1 if @_ < 5;	834	$a = 1 if @_ < 4;
87		835
88	$img = $img->clone;	836	$img = $img->clone;
89	$img->contrast ($r, $g, $b, $a);	837	$img->contrast ($r, $g, $b, $a);
90	$img	838	$img
91	}	839	}
92		840
93	sub brightness($$;$$;$) {	841	sub brightness($$;$$;$) {
94	my $img = pop;	842	my $img = pop;
95	my ($r, $g, $b, $a) = @_;	843	my ($r, $g, $b, $a) = @_;
96		844
97	($g, $b) = ($r, $r) if @_ < 4;	845	($g, $b) = ($r, $r) if @_ < 3;
98	$a = 1 if @_ < 5;	846	$a = 1 if @_ < 4;
99		847
100	$img = $img->clone;	848	$img = $img->clone;
101	$img->brightness ($r, $g, $b, $a);	849	$img->brightness ($r, $g, $b, $a);
102	$img	850	$img
103	}	851	}
104		852
105	sub X() { $new->{position_sensitive} = 1; $l }	853	=item blur $radius, $img
106	sub Y() { $new->{position_sensitive} = 1; $t }
107	sub W() { $new->{size_sensitive} = 1; $w }
108	sub H() { $new->{size_sensitive} = 1; $h }
109		854
110	sub now() { urxvt::NOW }	855	=item blur $radius_horz, $radius_vert, $img
111		856
112	sub again($) {	857	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
113	$new->{again} = $_[0];	858	can also be specified separately.
		859
		860	Blurring is often I<very> slow, at least compared or other
		861	operators. Larger blur radii are slower than smaller ones, too, so if you
		862	don't want to freeze your screen for long times, start experimenting with
		863	low values for radius (<5).
		864
		865	=cut
		866
		867	sub blur($$;$) {
		868	my $img = pop;
		869	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
		870	}
		871
		872	=back
		873
		874	=head2 OTHER STUFF
		875
		876	Anything that didn't fit any of the other categories, even after applying
		877	force and closing our eyes.
		878
		879	=over 4
		880
		881	=item keep { ... }
		882
		883	This operator takes a code block as argument, that is, one or more
		884	statements enclosed by braces.
		885
		886	The trick is that this code block is only evaluated when the outcome
		887	changes - on other calls the C<keep> simply returns the image it computed
		888	previously (yes, it should only be used with images). Or in other words,
		889	C<keep> I<caches> the result of the code block so it doesn't need to be
		890	computed again.
		891
		892	This can be extremely useful to avoid redoing slow operations - for
		893	example, if your background expression takes the root background, blurs it
		894	and then root-aligns it it would have to blur the root background on every
		895	window move or resize.
		896
		897	Another example is C<load>, which can be quite slow.
		898
		899	In fact, urxvt itself encloses the whole expression in some kind of
		900	C<keep> block so it only is reevaluated as required.
		901
		902	Putting the blur into a C<keep> block will make sure the blur is only done
		903	once, while the C<rootalign> is still done each time the window moves.
		904
		905	rootlign keep { blur 10, root }
		906
		907	This leaves the question of how to force reevaluation of the block,
		908	in case the root background changes: If expression inside the block
		909	is sensitive to some event (root background changes, window geometry
		910	changes), then it will be reevaluated automatically as needed.
		911
		912	=cut
		913
		914	sub keep(&) {
		915	my $id = $_[0]+0;
		916
		917	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		918
		919	unless ($frame->[FR_CACHE]) {
		920	$frame->[FR_CACHE] = [ $_[0]() ];
		921
		922	my $self = $self;
		923	my $frame = $frame;
		924	Scalar::Util::weaken $frame;
		925	$self->compile_frame ($frame, sub {
		926	# clear this frame cache, also for all parents
		927	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		928	undef $frame->[FR_CACHE];
		929	}
		930
		931	$self->recalculate;
		932	});
		933	};
		934
		935	# in scalar context we always return the first original result, which
		936	# is not quite how perl works.
		937	wantarray
		938	? @{ $frame->[FR_CACHE] }
		939	: $frame->[FR_CACHE][0]
		940	}
		941
		942	# sub keep_clear() {
		943	# delete $self->{frame_cache};
114	}	944	# }
115		945
116	sub counter($) {	946	=back
117	$new->{again} = $_[0];	947
118	$bgdsl_self->{counter} + 0	948	=cut
119	}	949
120	}	950	}
121		951
122	sub parse_expr {	952	sub parse_expr {
123	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	953	my $expr = eval
		954	"sub {\n"
		955	. "package urxvt::bgdsl;\n"
		956	. "#line 0 'background expression'\n"
		957	. "$_[0]\n"
		958	. "}";
124	die if $@;	959	die if $@;
125	$expr	960	$expr
126	}	961	}
127		962
128	# compiles a parsed expression	963	# compiles a parsed expression
129	sub set_expr {	964	sub set_expr {
130	my ($self, $expr) = @_;	965	my ($self, $expr) = @_;
131		966
		967	$self->{root} = [];
132	$self->{expr} = $expr;	968	$self->{expr} = $expr;
133	$self->recalculate;	969	$self->recalculate;
134	}	970	}
135		971
		972	# takes a hash of sensitivity indicators and installs watchers
		973	sub compile_frame {
		974	my ($self, $frame, $cb) = @_;
		975
		976	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		977	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		978
		979	# don't keep stuff alive
		980	Scalar::Util::weaken $state;
		981
		982	if ($again->{nested}) {
		983	$state->{nested} = 1;
		984	} else {
		985	delete $state->{nested};
		986	}
		987
		988	if (my $interval = $again->{time}) {
		989	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		990	if $state->{time}[0] != $interval;
		991
		992	# callback might have changed, although we could just rule that out
		993	$state->{time}[1]->cb (sub {
		994	++$state->{counter};
		995	$cb->();
		996	});
		997	} else {
		998	delete $state->{time};
		999	}
		1000
		1001	if ($again->{position}) {
		1002	$state->{position} = $self->on (position_change => $cb);
		1003	} else {
		1004	delete $state->{position};
		1005	}
		1006
		1007	if ($again->{size}) {
		1008	$state->{size} = $self->on (size_change => $cb);
		1009	} else {
		1010	delete $state->{size};
		1011	}
		1012
		1013	if ($again->{rootpmap}) {
		1014	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		1015	} else {
		1016	delete $state->{rootpmap};
		1017	}
		1018	}
		1019
136	# evaluate the current bg expression	1020	# evaluate the current bg expression
137	sub recalculate {	1021	sub recalculate {
138	my ($self) = @_;	1022	my ($arg_self) = @_;
139		1023
140	#TODO: rate limit calls	1024	# rate limit evaluation
141		1025
142	local $bgdsl_self = $self;	1026	if ($arg_self->{next_refresh} > urxvt::NOW) {
		1027	$arg_self->{next_refresh_timer} = urxvt::timer->new->after ($arg_self->{next_refresh} - urxvt::NOW)->cb (sub {
		1028	$arg_self->recalculate;
		1029	});
		1030	return;
		1031	}
143		1032
144	local $old = $self->{state};	1033	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
145	local $new = my $state = $self->{state} = {};
146		1034
147	($l, $t, $w, $h) =	1035	# set environment to evaluate user expression
148	$self->get_geometry;
149		1036
		1037	local $self = $arg_self;
		1038	local $HOME = $ENV{HOME};
		1039	local $frame = [];
		1040
		1041	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
		1042
		1043	# evaluate user expression
		1044
150	my $img = eval { $self->{expr}->() };	1045	my @img = eval { $self->{expr}->() };
151	warn $@ if $@;#d#	1046	die $@ if $@;
		1047	die "background-expr did not return anything.\n" unless @img;
		1048	die "background-expr: expected image(s), got something else.\n"
		1049	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
152		1050
153	my $repeat;	1051	my $img = urxvt::bgdsl::merge @img;
154		1052
155	if (my $again = $state->{again}) {	1053	$frame->[FR_AGAIN]{size} = 1
156	$repeat = 1;	1054	if $img->repeat_mode != urxvt::RepeatNormal;
157	$state->{timer} = $again == $old->{again}
158	? $old->{timer}
159	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
160	++$self->{counter};
161	$self->recalculate
162	});
163	}
164		1055
165	if (delete $state->{position_sensitive}) {	1056	# if the expression is sensitive to external events, prepare reevaluation then
166	$repeat = 1;	1057	$self->compile_frame ($frame, sub { $arg_self->recalculate });
167	$self->enable (position_change => sub { $_[0]->recalculate });
168	} else {
169	$self->disable ("position_change");
170	}
171		1058
172	if (delete $state->{size_sensitive}) {	1059	# clear stuff we no longer need
173	$repeat = 1;
174	$self->enable (size_change => sub { $_[0]->recalculate });
175	} else {
176	$self->disable ("size_change");
177	}
178		1060
179	%$old = ();	1061	# unless (%{ $frame->[FR_STATE] }) {
180
181	unless ($repeat) {
182	delete $self->{state};	1062	# delete $self->{state};
183	delete $self->{expr};	1063	# delete $self->{expr};
184	}	1064	# }
185		1065
186	$img = $img->sub_rect (0, 0, $w, $h)	1066	# set background pixmap
187	if $img->w != $w \|\| $img->h != $h;
188		1067
189	$self->set_background ($img);	1068	$self->set_background ($img, $self->{border});
190	$self->scr_recolour (0);	1069	$self->scr_recolour (0);
191	$self->want_refresh;	1070	$self->want_refresh;
192	}	1071	}
193		1072
194	sub on_start {	1073	sub on_start {
195	my ($self) = @_;	1074	my ($self) = @_;
196		1075
		1076	my $expr = $self->x_resource ("%.expr")
		1077	or return;
		1078
		1079	$self->has_render
		1080	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1081
197	$self->set_expr (parse_expr $EXPR);	1082	$self->set_expr (parse_expr $expr);
		1083	$self->{border} = $self->x_resource_boolean ("%.border");
		1084
		1085	$MIN_INTERVAL = $self->x_resource ("%.interval");
198		1086
199	()	1087	()
200	}	1088	}
201		1089

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.8 by root, Tue Jun 5 14:07:47 2012 UTC vs. Revision 1.71 by root, Mon Jul 2 01:40:41 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.8 by root, Tue Jun 5 14:07:47 2012 UTC vs.
Revision 1.71 by root, Mon Jul 2 01:40:41 2012 UTC