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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.2 by root, Tue Jun 5 11:00:40 2012 UTC vs.
Revision 1.70 by root, Mon Jul 2 01:35:37 2012 UTC

1	#! perl	1	#! perl
2		2
3	our $EXPR = 'move load "/root/pix/das_fette_schwein.jpg", &x, &y';	3	#:META:X_RESOURCE:%.expr:string:background expression
4	#$EXPR = 'blur root, 10, 10'	4	#:META:X_RESOURCE:%.border:boolean:respect the terminal border
5	#$EXPR = 'blur move (root, -x, -y), 5, 5'	5	#:META:X_RESOURCE:%.interval:seconds:minimum time between updates
6	#resize load "/root/pix/das_fette_schwein.jpg", w, h
7		6
8	use Safe;	7	=head1 NAME
		8
		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 CACHING AND SENSITIVITY
		163
		164	Since some operations (such as C<load> and C<blur>) can take a long time,
		165	caching results can be very important for a smooth operation. Caching can
		166	also be useful to reduce memory usage, though, for example, when an image
		167	is cached by C<load>, it could be shared by multiple terminal windows
		168	running inside urxvtd.
		169
		170	=head3 C<keep { ... }> caching
		171
		172	The most important way to cache expensive operations is to use C<keep {
		173	... }>. The C<keep> operator takes a block of multiple statements enclosed
		174	by C<{}> and keeps the return value in memory.
		175
		176	An expression can be "sensitive" to various external events, such as
		177	scaling or moving the window, root background changes and timers. Simply
		178	using an expression (such as C<scale> without parameters) that depends on
		179	certain changing values (called "variables"), or using those variables
		180	directly, will make an expression sensitive to these events - for example,
		181	using C<scale> or C<TW> will make the expression sensitive to the terminal
		182	size, and thus to resizing events.
		183
		184	When such an event happens, C<keep> will automatically trigger a
		185	reevaluation of the whole expression with the new value of the expression.
		186
		187	C<keep> is most useful for expensive operations, such as C<blur>:
		188
		189	rootalign keep { blur 20, root }
		190
		191	This makes a blurred copy of the root background once, and on subsequent
		192	calls, just root-aligns it. Since C<blur> is usually quite slow and
		193	C<rootalign> is quite fast, this trades extra memory (for the cached
		194	blurred pixmap) with speed (blur only needs to be redone when root
		195	changes).
		196
		197	=head3 C<load> caching
		198
		199	The C<load> operator itself does not keep images in memory, but as long as
		200	the image is still in memory, C<load> will use the in-memory image instead
		201	of loading it freshly from disk.
		202
		203	That means that this expression:
		204
		205	keep { load "$HOME/path..." }
		206
		207	Not only caches the image in memory, other terminal instances that try to
		208	C<load> it can reuse that in-memory copy.
		209
		210	=head1 REFERENCE
		211
		212	=head2 COMMAND LINE SWITCHES
		213
		214	=over 4
		215
		216	=item --background-expr perl-expression
		217
		218	Specifies the Perl expression to evaluate.
		219
		220	=item --background-border
		221
		222	By default, the expression creates an image that fills the full window,
		223	overwriting borders and any other areas, such as the scrollbar.
		224
		225	Specifying this flag changes the behaviour, so that the image only
		226	replaces the background of the character area.
		227
		228	=item --background-interval seconds
		229
		230	Since some operations in the underlying XRender extension can effectively
		231	freeze your X-server for prolonged time, this extension enforces a minimum
		232	time between updates, which is normally about 0.1 seconds.
		233
		234	If you want to do updates more often, you can decrease this safety
		235	interval with this switch.
		236
		237	=back
		238
		239	=cut
		240
		241	our %_IMG_CACHE;
		242	our $HOME;
		243	our ($self, $frame);
		244	our ($x, $y, $w, $h);
		245
		246	# enforce at least this interval between updates
		247	our $MIN_INTERVAL = 6/59.951;
9		248
10	{	249	{
11	package urxvt::bgdsl::vars;
12
13	our ($self, $old, $new);
14	our ($x, $y, $w, $h);
15
16	package urxvt::bgdsl; # background language	250	package urxvt::bgdsl; # background language
17		251
18	*repeat_black = \&urxvt::RepeatNone; #TODO wtf	252	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
19	*repeat_wrap = \&urxvt::RepeatNormal;	253	sub FR_CACHE () { 1 } # cached values
20	*repeat_pad = \&urxvt::RepeatPad;	254	sub FR_AGAIN () { 2 } # what this expr is sensitive to
21	*repeat_mirror = \&urxvt::RepeatReflect;	255	sub FR_STATE () { 3 } # watchers etc.
		256
		257	use List::Util qw(min max sum shuffle);
		258
		259	=head2 PROVIDERS/GENERATORS
		260
		261	These functions provide an image, by loading it from disk, grabbing it
		262	from the root screen or by simply generating it. They are used as starting
		263	points to get an image you can play with.
		264
		265	=over 4
		266
		267	=item load $path
		268
		269	Loads the image at the given C<$path>. The image is set to plane tiling
		270	mode.
		271
		272	If the image is already in memory (e.g. because another terminal instance
		273	uses it), then the in-memory copy us returned instead.
		274
		275	=item load_uc $path
		276
		277	Load uncached - same as load, but does not cache the image, which means it
		278	is I<always> loaded from the filesystem again.
		279
		280	=cut
22		281
23	sub load($) {	282	sub load($) {
24	my ($path) = @_;	283	my ($path) = @_;
25		284
26	$new->{load}{$path} = $old->{load}{$path} \|\| $self->new_img_from_file ($path);	285	$_IMG_CACHE{$path} \|\| do {
		286	my $img = $self->new_img_from_file ($path);
		287	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		288	$img
		289	}
27	}	290	}
		291
		292	=item root
		293
		294	Returns the root window pixmap, that is, hopefully, the background image
		295	of your screen.
		296
		297	This function makes your expression root sensitive, that means it will be
		298	reevaluated when the bg image changes.
		299
		300	=cut
28		301
29	sub root() {	302	sub root() {
30	die "root op not supported, exg, we need you";	303	$frame->[FR_AGAIN]{rootpmap} = 1;
		304	$self->new_img_from_root
		305	}
		306
		307	=item solid $colour
		308
		309	=item solid $width, $height, $colour
		310
		311	Creates a new image and completely fills it with the given colour. The
		312	image is set to tiling mode.
		313
		314	If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
		315	useful for solid backgrounds or for use in filtering effects.
		316
		317	=cut
		318
		319	sub solid($;$$) {
		320	my $colour = pop;
		321
		322	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
		323	$img->fill ($colour);
		324	$img
		325	}
		326
		327	=item clone $img
		328
		329	Returns an exact copy of the image. This is useful if you want to have
		330	multiple copies of the same image to apply different effects to.
		331
		332	=cut
		333
		334	sub clone($) {
		335	$_[0]->clone
		336	}
		337
		338	=item merge $img ...
		339
		340	Takes any number of images and merges them together, creating a single
		341	image containing them all. The tiling mode of the first image is used as
		342	the tiling mode of the resulting image.
		343
		344	This function is called automatically when an expression returns multiple
		345	images.
		346
		347	=cut
		348
		349	sub merge(@) {
		350	return $_[0] unless $#_;
		351
		352	# rather annoyingly clumsy, but optimisation is for another time
		353
		354	my $x0 = +1e9;
		355	my $y0 = +1e9;
		356	my $x1 = -1e9;
		357	my $y1 = -1e9;
		358
		359	for (@_) {
		360	my ($x, $y, $w, $h) = $_->geometry;
		361
		362	$x0 = $x if $x0 > $x;
		363	$y0 = $y if $y0 > $y;
		364
		365	$x += $w;
		366	$y += $h;
		367
		368	$x1 = $x if $x1 < $x;
		369	$y1 = $y if $y1 < $y;
		370	}
		371
		372	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		373	$base->repeat_mode ($_[0]->repeat_mode);
		374	$base->fill ([0, 0, 0, 0]);
		375
		376	$base->draw ($_)
		377	for @_;
		378
		379	$base
		380	}
		381
		382	=head2 TILING MODES
		383
		384	The following operators modify the tiling mode of an image, that is, the
		385	way that pixels outside the image area are painted when the image is used.
		386
		387	=over 4
		388
		389	=item tile $img
		390
		391	Tiles the whole plane with the image and returns this new image - or in
		392	other words, it returns a copy of the image in plane tiling mode.
		393
		394	Example: load an image and tile it over the background, without
		395	resizing. The C<tile> call is superfluous because C<load> already defaults
		396	to tiling mode.
		397
		398	tile load "mybg.png"
		399
		400	=item mirror $img
		401
		402	Similar to tile, but reflects the image each time it uses a new copy, so
		403	that top edges always touch top edges, right edges always touch right
		404	edges and so on (with normal tiling, left edges always touch right edges
		405	and top always touch bottom edges).
		406
		407	Example: load an image and mirror it over the background, avoiding sharp
		408	edges at the image borders at the expense of mirroring the image itself
		409
		410	mirror load "mybg.png"
		411
		412	=item pad $img
		413
		414	Takes an image and modifies it so that all pixels outside the image area
		415	become transparent. This mode is most useful when you want to place an
		416	image over another image or the background colour while leaving all
		417	background pixels outside the image unchanged.
		418
		419	Example: load an image and display it in the upper left corner. The rest
		420	of the space is left "empty" (transparent or whatever your compositor does
		421	in alpha mode, else background colour).
		422
		423	pad load "mybg.png"
		424
		425	=item extend $img
		426
		427	Extends the image over the whole plane, using the closest pixel in the
		428	area outside the image. This mode is mostly useful when you use more complex
		429	filtering operations and want the pixels outside the image to have the
		430	same values as the pixels near the edge.
		431
		432	Example: just for curiosity, how does this pixel extension stuff work?
		433
		434	extend move 50, 50, load "mybg.png"
		435
		436	=cut
		437
		438	sub pad($) {
		439	my $img = $_[0]->clone;
		440	$img->repeat_mode (urxvt::RepeatNone);
		441	$img
		442	}
		443
		444	sub tile($) {
		445	my $img = $_[0]->clone;
		446	$img->repeat_mode (urxvt::RepeatNormal);
		447	$img
		448	}
		449
		450	sub mirror($) {
		451	my $img = $_[0]->clone;
		452	$img->repeat_mode (urxvt::RepeatReflect);
		453	$img
		454	}
		455
		456	sub extend($) {
		457	my $img = $_[0]->clone;
		458	$img->repeat_mode (urxvt::RepeatPad);
		459	$img
		460	}
		461
		462	=back
		463
		464	=head2 VARIABLE VALUES
		465
		466	The following functions provide variable data such as the terminal window
		467	dimensions. They are not (Perl-) variables, they just return stuff that
		468	varies. Most of them make your expression sensitive to some events, for
		469	example using C<TW> (terminal width) means your expression is evaluated
		470	again when the terminal is resized.
		471
		472	=over 4
		473
		474	=item TX
		475
		476	=item TY
		477
		478	Return the X and Y coordinates of the terminal window (the terminal
		479	window is the full window by default, and the character area only when in
		480	border-respect mode).
		481
		482	Using these functions make your expression sensitive to window moves.
		483
		484	These functions are mainly useful to align images to the root window.
		485
		486	Example: load an image and align it so it looks as if anchored to the
		487	background (that's exactly what C<rootalign> does btw.):
		488
		489	move -TX, -TY, keep { load "mybg.png" }
		490
		491	=item TW
		492
		493	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		494	terminal window is the full window by default, and the character area only
		495	when in border-respect mode).
		496
		497	Using these functions make your expression sensitive to window resizes.
		498
		499	These functions are mainly useful to scale images, or to clip images to
		500	the window size to conserve memory.
		501
		502	Example: take the screen background, clip it to the window size, blur it a
		503	bit, align it to the window position and use it as background.
		504
		505	clip move -TX, -TY, keep { blur 5, root }
		506
		507	=cut
		508
		509	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
		510	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
		511	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
		512	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
		513
		514	=item now
		515
		516	Returns the current time as (fractional) seconds since the epoch.
		517
		518	Using this expression does I<not> make your expression sensitive to time,
		519	but the next two functions do.
		520
		521	=item again $seconds
		522
		523	When this function is used the expression will be reevaluated again in
		524	C<$seconds> seconds.
		525
		526	Example: load some image and rotate it according to the time of day (as if it were
		527	the hour pointer of a clock). Update this image every minute.
		528
		529	again 60;
		530	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
		531
		532	=item counter $seconds
		533
		534	Like C<again>, but also returns an increasing counter value, starting at
		535	0, which might be useful for some simple animation effects.
		536
		537	=cut
		538
		539	sub now() { urxvt::NOW }
		540
		541	sub again($) {
		542	$frame->[FR_AGAIN]{time} = $_[0];
		543	}
		544
		545	sub counter($) {
		546	$frame->[FR_AGAIN]{time} = $_[0];
		547	$frame->[FR_STATE]{counter} + 0
		548	}
		549
		550	=back
		551
		552	=head2 SHAPE CHANGING OPERATORS
		553
		554	The following operators modify the shape, size or position of the image.
		555
		556	=over 4
		557
		558	=item clip $img
		559
		560	=item clip $width, $height, $img
		561
		562	=item clip $x, $y, $width, $height, $img
		563
		564	Clips an image to the given rectangle. If the rectangle is outside the
		565	image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is
		566	larger than the image, then the tiling mode defines how the extra pixels
		567	will be filled.
		568
		569	If C<$x> an C<$y> are missing, then C<0> is assumed for both.
		570
		571	If C<$width> and C<$height> are missing, then the window size will be
		572	assumed.
		573
		574	Example: load an image, blur it, and clip it to the window size to save
		575	memory.
		576
		577	clip keep { blur 10, load "mybg.png" }
		578
		579	=cut
		580
		581	sub clip($;$$;$$) {
		582	my $img = pop;
		583	my $h = pop \|\| TH;
		584	my $w = pop \|\| TW;
		585	$img->sub_rect ($_[0], $_[1], $w, $h)
		586	}
		587
		588	=item scale $img
		589
		590	=item scale $size_factor, $img
		591
		592	=item scale $width_factor, $height_factor, $img
		593
		594	Scales the image by the given factors in horizontal
		595	(C<$width>) and vertical (C<$height>) direction.
		596
		597	If only one factor is give, it is used for both directions.
		598
		599	If no factors are given, scales the image to the window size without
		600	keeping aspect.
		601
		602	=item resize $width, $height, $img
		603
		604	Resizes the image to exactly C<$width> times C<$height> pixels.
		605
		606	=item fit $img
		607
		608	=item fit $width, $height, $img
		609
		610	Fits the image into the given C<$width> and C<$height> without changing
		611	aspect, or the terminal size. That means it will be shrunk or grown until
		612	the whole image fits into the given area, possibly leaving borders.
		613
		614	=item cover $img
		615
		616	=item cover $width, $height, $img
		617
		618	Similar to C<fit>, but shrinks or grows until all of the area is covered
		619	by the image, so instead of potentially leaving borders, it will cut off
		620	image data that doesn't fit.
		621
		622	=cut
		623
		624	sub scale($;$;$) {
		625	my $img = pop;
		626
		627	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
		628	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
		629	: $img->scale (TW, TH)
31	}	630	}
32		631
33	sub resize($$$) {	632	sub resize($$$) {
34	$_[0]->scale ($_[1], $_[2])	633	my $img = pop;
		634	$img->scale ($_[0], $_[1])
35	}	635	}
36		636
		637	sub fit($;$$) {
		638	my $img = pop;
		639	my $w = ($_[0] \|\| TW) / $img->w;
		640	my $h = ($_[1] \|\| TH) / $img->h;
		641	scale +(min $w, $h), $img
		642	}
		643
		644	sub cover($;$$) {
		645	my $img = pop;
		646	my $w = ($_[0] \|\| TW) / $img->w;
		647	my $h = ($_[1] \|\| TH) / $img->h;
		648	scale +(max $w, $h), $img
		649	}
		650
		651	=item move $dx, $dy, $img
		652
		653	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
		654	the vertical.
		655
		656	Example: move the image right by 20 pixels and down by 30.
		657
		658	move 20, 30, ...
		659
		660	=item align $xalign, $yalign, $img
		661
		662	Aligns the image according to a factor - C<0> means the image is moved to
		663	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		664	exactly centered and C<1> means it touches the right or bottom edge.
		665
		666	Example: remove any visible border around an image, center it vertically but move
		667	it to the right hand side.
		668
		669	align 1, 0.5, pad $img
		670
		671	=item center $img
		672
		673	=item center $width, $height, $img
		674
		675	Centers the image, i.e. the center of the image is moved to the center of
		676	the terminal window (or the box specified by C<$width> and C<$height> if
		677	given).
		678
		679	Example: load an image and center it.
		680
		681	center keep { pad load "mybg.png" }
		682
		683	=item rootalign $img
		684
		685	Moves the image so that it appears glued to the screen as opposed to the
		686	window. This gives the illusion of a larger area behind the window. It is
		687	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
		688	top left of the screen.
		689
		690	Example: load a background image, put it in mirror mode and root align it.
		691
		692	rootalign keep { mirror load "mybg.png" }
		693
		694	Example: take the screen background and align it, giving the illusion of
		695	transparency as long as the window isn't in front of other windows.
		696
		697	rootalign root
		698
		699	=cut
		700
37	sub move($$$) {	701	sub move($$;$) {
38	# TODO: must be simpler	702	my $img = pop->clone;
39	$_[0]->transform ($_[0]->w, $_[0]->h, $_[1],	703	$img->move ($_[0], $_[1]);
40	1, 0, -$_[2],	704	$img
41	0, 1, -$_[3],	705	}
42	0, 0, 1,	706
		707	sub align($;$$) {
		708	my $img = pop;
		709
		710	move $_[0] * (TW - $img->w),
		711	$_[1] * (TH - $img->h),
		712	$img
		713	}
		714
		715	sub center($;$$) {
		716	my $img = pop;
		717	my $w = $_[0] \|\| TW;
		718	my $h = $_[1] \|\| TH;
		719
		720	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		721	}
		722
		723	sub rootalign($) {
		724	move -TX, -TY, $_[0]
		725	}
		726
		727	=item rotate $center_x, $center_y, $degrees, $img
		728
		729	Rotates the image clockwise by C<$degrees> degrees, around the point at
		730	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		731
		732	Example: rotate the image by 90 degrees around it's center.
		733
		734	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		735
		736	=cut
		737
		738	sub rotate($$$$) {
		739	my $img = pop;
		740	$img->rotate (
		741	$_[0] * ($img->w + $img->x),
		742	$_[1] * ($img->h + $img->y),
		743	$_[2] * (3.14159265 / 180),
43	)	744	)
44	}	745	}
45		746
		747	=back
		748
		749	=head2 COLOUR MODIFICATIONS
		750
		751	The following operators change the pixels of the image.
		752
		753	=over 4
		754
		755	=item tint $color, $img
		756
		757	Tints the image in the given colour.
		758
		759	Example: tint the image red.
		760
		761	tint "red", load "rgb.png"
		762
		763	Example: the same, but specify the colour by component.
		764
		765	tint [1, 0, 0], load "rgb.png"
		766
		767	=cut
		768
46	sub rotate($$$$) {	769	sub tint($$) {
47	$_[0]->rotate ($_[0], $_[1], $_[2], $_[3] * (3.14159265 / 180))	770	$_[1]->tint ($_[0])
48	}	771	}
49		772
50	sub blur($$$) {	773	=item contrast $factor, $img
51	my ($img, $rh, $rv) = @_;
52		774
53	$img = $img->clone;	775	=item contrast $r, $g, $b, $img
54	$img->clone->blur ($rh, $rv);	776
55	$img	777	=item contrast $r, $g, $b, $a, $img
56	}	778
		779	Adjusts the I<contrast> of an image.
		780
		781	The first form applies a single C<$factor> to red, green and blue, the
		782	second form applies separate factors to each colour channel, and the last
		783	form includes the alpha channel.
		784
		785	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		786	contrast.
		787
		788	Due to limitations in the underlying XRender extension, lowering contrast
		789	also reduces brightness, while increasing contrast currently also
		790	increases brightness.
		791
		792	=item brightness $bias, $img
		793
		794	=item brightness $r, $g, $b, $img
		795
		796	=item brightness $r, $g, $b, $a, $img
		797
		798	Adjusts the brightness of an image.
		799
		800	The first form applies a single C<$bias> to red, green and blue, the
		801	second form applies separate biases to each colour channel, and the last
		802	form includes the alpha channel.
		803
		804	Values less than 0 reduce brightness, while values larger than 0 increase
		805	it. Useful range is from -1 to 1 - the former results in a black, the
		806	latter in a white picture.
		807
		808	Due to idiosyncrasies in the underlying XRender extension, biases less
		809	than zero can be I<very> slow.
		810
		811	=cut
57		812
58	sub contrast($$;$$;$) {	813	sub contrast($$;$$;$) {
		814	my $img = pop;
59	my ($img, $r, $g, $b, $a) = @_;	815	my ($r, $g, $b, $a) = @_;
		816
60	($g, $b) = ($r, $r) if @_ < 4;	817	($g, $b) = ($r, $r) if @_ < 3;
61	$a = 1 if @_ < 5;	818	$a = 1 if @_ < 4;
		819
62	$img = $img->clone;	820	$img = $img->clone;
63	$img->contrast ($r, $g, $b, $a);	821	$img->contrast ($r, $g, $b, $a);
64	$img	822	$img
65	}	823	}
66		824
67	sub brightness($$;$$;$) {	825	sub brightness($$;$$;$) {
		826	my $img = pop;
68	my ($img, $r, $g, $b, $a) = @_;	827	my ($r, $g, $b, $a) = @_;
		828
69	($g, $b) = ($r, $r) if @_ < 4;	829	($g, $b) = ($r, $r) if @_ < 3;
70	$a = 1 if @_ < 5;	830	$a = 1 if @_ < 4;
		831
71	$img = $img->clone;	832	$img = $img->clone;
72	$img->brightness ($r, $g, $b, $a);	833	$img->brightness ($r, $g, $b, $a);
73	$img	834	$img
74	}	835	}
75		836
76	sub x() { $new->{position_sensitive} = 1; $x }	837	=item blur $radius, $img
77	sub y() { $new->{position_sensitive} = 1; $y }
78	sub w() { $new->{size_sensitive} = 1; $w }
79	sub h() { $new->{size_sensitive} = 1; $h }
80	sub now() { urxvt::NOW }
81		838
82	sub again($) {	839	=item blur $radius_horz, $radius_vert, $img
83	$new->{again} = $_[0];	840
		841	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
		842	can also be specified separately.
		843
		844	Blurring is often I<very> slow, at least compared or other
		845	operators. Larger blur radii are slower than smaller ones, too, so if you
		846	don't want to freeze your screen for long times, start experimenting with
		847	low values for radius (<5).
		848
		849	=cut
		850
		851	sub blur($$;$) {
		852	my $img = pop;
		853	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
		854	}
		855
		856	=back
		857
		858	=head2 OTHER STUFF
		859
		860	Anything that didn't fit any of the other categories, even after applying
		861	force and closing our eyes.
		862
		863	=over 4
		864
		865	=item keep { ... }
		866
		867	This operator takes a code block as argument, that is, one or more
		868	statements enclosed by braces.
		869
		870	The trick is that this code block is only evaluated when the outcome
		871	changes - on other calls the C<keep> simply returns the image it computed
		872	previously (yes, it should only be used with images). Or in other words,
		873	C<keep> I<caches> the result of the code block so it doesn't need to be
		874	computed again.
		875
		876	This can be extremely useful to avoid redoing slow operations - for
		877	example, if your background expression takes the root background, blurs it
		878	and then root-aligns it it would have to blur the root background on every
		879	window move or resize.
		880
		881	Another example is C<load>, which can be quite slow.
		882
		883	In fact, urxvt itself encloses the whole expression in some kind of
		884	C<keep> block so it only is reevaluated as required.
		885
		886	Putting the blur into a C<keep> block will make sure the blur is only done
		887	once, while the C<rootalign> is still done each time the window moves.
		888
		889	rootlign keep { blur 10, root }
		890
		891	This leaves the question of how to force reevaluation of the block,
		892	in case the root background changes: If expression inside the block
		893	is sensitive to some event (root background changes, window geometry
		894	changes), then it will be reevaluated automatically as needed.
		895
		896	=cut
		897
		898	sub keep(&) {
		899	my $id = $_[0]+0;
		900
		901	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		902
		903	unless ($frame->[FR_CACHE]) {
		904	$frame->[FR_CACHE] = [ $_[0]() ];
		905
		906	my $self = $self;
		907	my $frame = $frame;
		908	Scalar::Util::weaken $frame;
		909	$self->compile_frame ($frame, sub {
		910	# clear this frame cache, also for all parents
		911	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		912	undef $frame->[FR_CACHE];
		913	}
		914
		915	$self->recalculate;
		916	});
		917	};
		918
		919	# in scalar context we always return the first original result, which
		920	# is not quite how perl works.
		921	wantarray
		922	? @{ $frame->[FR_CACHE] }
		923	: $frame->[FR_CACHE][0]
		924	}
		925
		926	# sub keep_clear() {
		927	# delete $self->{frame_cache};
84	}	928	# }
85		929
86	sub counter($) {	930	=back
87	$new->{again} = $_[0];	931
88	$self->{counter}++ + 0	932	=cut
89	}	933
90	}	934	}
91		935
92	sub parse_expr {	936	sub parse_expr {
93	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	937	my $expr = eval
		938	"sub {\n"
		939	. "package urxvt::bgdsl;\n"
		940	. "#line 0 'background expression'\n"
		941	. "$_[0]\n"
		942	. "}";
94	die if $@;	943	die if $@;
95	$expr	944	$expr
96	}	945	}
97		946
98	# compiles a parsed expression	947	# compiles a parsed expression
99	sub set_expr {	948	sub set_expr {
100	my ($self, $expr) = @_;	949	my ($self, $expr) = @_;
101		950
102	local $Data::Dumper::Deparse=1; use Data::Dumper; warn Dumper $expr;#d#	951	$self->{root} = [];
103	$self->{expr} = $expr;	952	$self->{expr} = $expr;
104	$self->recalculate;	953	$self->recalculate;
105	}	954	}
106		955
		956	# takes a hash of sensitivity indicators and installs watchers
		957	sub compile_frame {
		958	my ($self, $frame, $cb) = @_;
		959
		960	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		961	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		962
		963	# don't keep stuff alive
		964	Scalar::Util::weaken $state;
		965
		966	if ($again->{nested}) {
		967	$state->{nested} = 1;
		968	} else {
		969	delete $state->{nested};
		970	}
		971
		972	if (my $interval = $again->{time}) {
		973	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		974	if $state->{time}[0] != $interval;
		975
		976	# callback might have changed, although we could just rule that out
		977	$state->{time}[1]->cb (sub {
		978	++$state->{counter};
		979	$cb->();
		980	});
		981	} else {
		982	delete $state->{time};
		983	}
		984
		985	if ($again->{position}) {
		986	$state->{position} = $self->on (position_change => $cb);
		987	} else {
		988	delete $state->{position};
		989	}
		990
		991	if ($again->{size}) {
		992	$state->{size} = $self->on (size_change => $cb);
		993	} else {
		994	delete $state->{size};
		995	}
		996
		997	if ($again->{rootpmap}) {
		998	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		999	} else {
		1000	delete $state->{rootpmap};
		1001	}
		1002	}
		1003
107	# evaluate the current bg expression	1004	# evaluate the current bg expression
108	sub recalculate {	1005	sub recalculate {
109	my ($self) = @_;	1006	my ($arg_self) = @_;
110		1007
111	local $urxvt::bgdsl::vars::self = $self;	1008	# rate limit evaluation
112		1009
113	local $urxvt::bgdsl::vars::old = $self->{state};	1010	if ($arg_self->{next_refresh} > urxvt::NOW) {
114	local $urxvt::bgdsl::vars::new = my $state = $self->{state} = {};	1011	$arg_self->{next_refresh_timer} = urxvt::timer->new->after ($arg_self->{next_refresh} - urxvt::NOW)->cb (sub {
		1012	$arg_self->recalculate;
		1013	});
		1014	return;
		1015	}
115		1016
116	($urxvt::bgdsl::vars::x, $urxvt::bgdsl::vars::y, $urxvt::bgdsl::vars::w, $urxvt::bgdsl::vars::h) =	1017	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
117	$self->get_geometry;
118		1018
		1019	# set environment to evaluate user expression
		1020
		1021	local $self = $arg_self;
		1022	local $HOME = $ENV{HOME};
		1023	local $frame = [];
		1024
		1025	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
		1026
		1027	# evaluate user expression
		1028
119	my $img = eval { $self->{expr}->() };	1029	my @img = eval { $self->{expr}->() };
120	warn $@ if $@;#d#	1030	die $@ if $@;
		1031	die "background-expr did not return anything.\n" unless @img;
		1032	die "background-expr: expected image(s), got something else.\n"
		1033	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
121		1034
122	my $repeat;	1035	my $img = urxvt::bgdsl::merge @img;
123		1036
124	if (my $again = $state->{again}) {	1037	$frame->[FR_AGAIN]{size} = 1
125	$repeat = 1;	1038	if $img->repeat_mode != urxvt::RepeatNormal;
126	$state->{again} = urxvt::timer->new->after ($again)->cb (sub { $self->recalculate });	1039
		1040	# if the expression is sensitive to external events, prepare reevaluation then
		1041	$self->compile_frame ($frame, sub { $arg_self->recalculate });
		1042
		1043	# clear stuff we no longer need
		1044
		1045	# unless (%{ $frame->[FR_STATE] }) {
		1046	# delete $self->{state};
		1047	# delete $self->{expr};
127	}	1048	# }
128		1049
129	if (delete $state->{position_sensitive}) {	1050	# set background pixmap
130	$repeat = 1;
131	$self->enable (position_change => sub { $_[0]->recalculate });
132	} else {
133	$self->disable ("position_change");
134	}
135		1051
136	if (delete $state->{size_sensitive}) {
137	$repeat = 1;
138	$self->enable (size_change => sub { $_[0]->recalculate });
139	} else {
140	$self->disable ("size_change");
141	}
142
143	# TODO: install handlers for geometry changes &c
144
145	warn $img;
146	$self->set_background ($img);	1052	$self->set_background ($img, $self->{border});
147	$self->scr_recolour (0);	1053	$self->scr_recolour (0);
148	$self->want_refresh;	1054	$self->want_refresh;
149	}	1055	}
150		1056
151	sub on_start {	1057	sub on_start {
152	my ($self) = @_;	1058	my ($self) = @_;
153		1059
		1060	my $expr = $self->x_resource ("%.expr")
		1061	or return;
		1062
		1063	$self->has_render
		1064	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1065
154	$self->set_expr (parse_expr $EXPR);	1066	$self->set_expr (parse_expr $expr);
		1067	$self->{border} = $self->x_resource_boolean ("%.border");
		1068
		1069	$MIN_INTERVAL = $self->x_resource ("%.interval");
155		1070
156	()	1071	()
157	}	1072	}
158		1073

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.2 by root, Tue Jun 5 11:00:40 2012 UTC vs. Revision 1.70 by root, Mon Jul 2 01:35:37 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.2 by root, Tue Jun 5 11:00:40 2012 UTC vs.
Revision 1.70 by root, Mon Jul 2 01:35:37 2012 UTC