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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.13 by root, Tue Jun 5 19:32:29 2012 UTC vs.
Revision 1.68 by root, Sun Jul 1 21:47:07 2012 UTC

1	#! perl	1	#! perl
2		2
3	#:META:RESOURCE:$$:string:background expression	3	#:META:X_RESOURCE:%.expr:string:background expression
		4	#:META:X_RESOURCE:%.border:boolean:respect the terminal border
		5	#:META:X_RESOURCE:%.interval:seconds:minimum time between updates
4		6
5	our $EXPR = 'move load "/root/pix/das_fette_schwein.jpg", repeat_wrap, X, Y';	7	=head1 NAME
6	$EXPR = '
7	rotate W, H, 50, 50, counter 1/59.95, repeat_mirror,
8	clip X, Y, W, H, repeat_mirror,
9	load "/root/pix/das_fette_schwein.jpg"
10	';
11	#$EXPR = 'blur root, 10, 10'
12	#$EXPR = 'blur move (root, -x, -y), 5, 5'
13	#resize load "/root/pix/das_fette_schwein.jpg", w, h
14		8
15	use Safe;	9	background - manage terminal background
16		10
17	our ($bgdsl_self, $old, $new);	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);
18	our ($l, $t, $w, $h);	244	our ($x, $y, $w, $h);
19		245
20	# enforce at leats this time between updates	246	# enforce at least this interval between updates
21	our $MIN_INTERVAL = 1/100;	247	our $MIN_INTERVAL = 6/59.951;
22		248
23	{	249	{
24	package urxvt::bgdsl; # background language	250	package urxvt::bgdsl; # background language
25		251
26	*repeat_black = \&urxvt::RepeatNone; #TODO wtf	252	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
27	*repeat_wrap = \&urxvt::RepeatNormal;	253	sub FR_CACHE () { 1 } # cached values
28	*repeat_pad = \&urxvt::RepeatPad;	254	sub FR_AGAIN () { 2 } # what this expr is sensitive to
29	*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
		281
		282	sub load_uc($) {
		283	$self->new_img_from_file ($path)
		284	}
30		285
31	sub load($) {	286	sub load($) {
32	my ($path) = @_;	287	my ($path) = @_;
33		288
34	$new->{load}{$path} = $old->{load}{$path} \|\| $bgdsl_self->new_img_from_file ($path);	289	$_IMG_CACHE{$path} \|\| do {
		290	my $img = load_uc $path;
		291	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		292	$img
		293	}
35	}	294	}
		295
		296	=item root
		297
		298	Returns the root window pixmap, that is, hopefully, the background image
		299	of your screen.
		300
		301	This function makes your expression root sensitive, that means it will be
		302	reevaluated when the bg image changes.
		303
		304	=cut
36		305
37	sub root() {	306	sub root() {
38	$new->{rootpmap_sensitive} = 1;	307	$frame->[FR_AGAIN]{rootpmap} = 1;
39	die "root op not supported, exg, we need you";	308	$self->new_img_from_root
40	}	309	}
41		310
		311	=item solid $colour
		312
		313	=item solid $width, $height, $colour
		314
		315	Creates a new image and completely fills it with the given colour. The
		316	image is set to tiling mode.
		317
		318	If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
		319	useful for solid backgrounds or for use in filtering effects.
		320
		321	=cut
		322
		323	sub solid($;$$) {
		324	my $colour = pop;
		325
		326	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
		327	$img->fill ($colour);
		328	$img
		329	}
		330
		331	=item clone $img
		332
		333	Returns an exact copy of the image. This is useful if you want to have
		334	multiple copies of the same image to apply different effects to.
		335
		336	=cut
		337
42	# sub clone($) {	338	sub clone($) {
43	# $_[0]->clone	339	$_[0]->clone
44	# }	340	}
45		341
		342	=item merge $img ...
		343
		344	Takes any number of images and merges them together, creating a single
		345	image containing them all. The tiling mode of the first image is used as
		346	the tiling mode of the resulting image.
		347
		348	This function is called automatically when an expression returns multiple
		349	images.
		350
		351	=cut
		352
		353	sub merge(@) {
		354	return $_[0] unless $#_;
		355
		356	# rather annoyingly clumsy, but optimisation is for another time
		357
		358	my $x0 = +1e9;
		359	my $y0 = +1e9;
		360	my $x1 = -1e9;
		361	my $y1 = -1e9;
		362
		363	for (@_) {
		364	my ($x, $y, $w, $h) = $_->geometry;
		365
		366	$x0 = $x if $x0 > $x;
		367	$y0 = $y if $y0 > $y;
		368
		369	$x += $w;
		370	$y += $h;
		371
		372	$x1 = $x if $x1 < $x;
		373	$y1 = $y if $y1 < $y;
		374	}
		375
		376	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		377	$base->repeat_mode ($_[0]->repeat_mode);
		378	$base->fill ([0, 0, 0, 0]);
		379
		380	$base->draw ($_)
		381	for @_;
		382
		383	$base
		384	}
		385
		386	=head2 TILING MODES
		387
		388	The following operators modify the tiling mode of an image, that is, the
		389	way that pixels outside the image area are painted when the image is used.
		390
		391	=over 4
		392
		393	=item tile $img
		394
		395	Tiles the whole plane with the image and returns this new image - or in
		396	other words, it returns a copy of the image in plane tiling mode.
		397
		398	Example: load an image and tile it over the background, without
		399	resizing. The C<tile> call is superfluous because C<load> already defaults
		400	to tiling mode.
		401
		402	tile load "mybg.png"
		403
		404	=item mirror $img
		405
		406	Similar to tile, but reflects the image each time it uses a new copy, so
		407	that top edges always touch top edges, right edges always touch right
		408	edges and so on (with normal tiling, left edges always touch right edges
		409	and top always touch bottom edges).
		410
		411	Example: load an image and mirror it over the background, avoiding sharp
		412	edges at the image borders at the expense of mirroring the image itself
		413
		414	mirror load "mybg.png"
		415
		416	=item pad $img
		417
		418	Takes an image and modifies it so that all pixels outside the image area
		419	become transparent. This mode is most useful when you want to place an
		420	image over another image or the background colour while leaving all
		421	background pixels outside the image unchanged.
		422
		423	Example: load an image and display it in the upper left corner. The rest
		424	of the space is left "empty" (transparent or whatever your compositor does
		425	in alpha mode, else background colour).
		426
		427	pad load "mybg.png"
		428
		429	=item extend $img
		430
		431	Extends the image over the whole plane, using the closest pixel in the
		432	area outside the image. This mode is mostly useful when you use more complex
		433	filtering operations and want the pixels outside the image to have the
		434	same values as the pixels near the edge.
		435
		436	Example: just for curiosity, how does this pixel extension stuff work?
		437
		438	extend move 50, 50, load "mybg.png"
		439
		440	=cut
		441
		442	sub pad($) {
		443	my $img = $_[0]->clone;
		444	$img->repeat_mode (urxvt::RepeatNone);
		445	$img
		446	}
		447
		448	sub tile($) {
		449	my $img = $_[0]->clone;
		450	$img->repeat_mode (urxvt::RepeatNormal);
		451	$img
		452	}
		453
		454	sub mirror($) {
		455	my $img = $_[0]->clone;
		456	$img->repeat_mode (urxvt::RepeatReflect);
		457	$img
		458	}
		459
		460	sub extend($) {
		461	my $img = $_[0]->clone;
		462	$img->repeat_mode (urxvt::RepeatPad);
		463	$img
		464	}
		465
		466	=back
		467
		468	=head2 VARIABLE VALUES
		469
		470	The following functions provide variable data such as the terminal window
		471	dimensions. They are not (Perl-) variables, they just return stuff that
		472	varies. Most of them make your expression sensitive to some events, for
		473	example using C<TW> (terminal width) means your expression is evaluated
		474	again when the terminal is resized.
		475
		476	=over 4
		477
		478	=item TX
		479
		480	=item TY
		481
		482	Return the X and Y coordinates of the terminal window (the terminal
		483	window is the full window by default, and the character area only when in
		484	border-respect mode).
		485
		486	Using these functions make your expression sensitive to window moves.
		487
		488	These functions are mainly useful to align images to the root window.
		489
		490	Example: load an image and align it so it looks as if anchored to the
		491	background (that's exactly what C<rootalign> does btw.):
		492
		493	move -TX, -TY, keep { load "mybg.png" }
		494
		495	=item TW
		496
		497	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		498	terminal window is the full window by default, and the character area only
		499	when in border-respect mode).
		500
		501	Using these functions make your expression sensitive to window resizes.
		502
		503	These functions are mainly useful to scale images, or to clip images to
		504	the window size to conserve memory.
		505
		506	Example: take the screen background, clip it to the window size, blur it a
		507	bit, align it to the window position and use it as background.
		508
		509	clip move -TX, -TY, keep { blur 5, root }
		510
		511	=cut
		512
		513	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
		514	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
		515	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
		516	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
		517
		518	=item now
		519
		520	Returns the current time as (fractional) seconds since the epoch.
		521
		522	Using this expression does I<not> make your expression sensitive to time,
		523	but the next two functions do.
		524
		525	=item again $seconds
		526
		527	When this function is used the expression will be reevaluated again in
		528	C<$seconds> seconds.
		529
		530	Example: load some image and rotate it according to the time of day (as if it were
		531	the hour pointer of a clock). Update this image every minute.
		532
		533	again 60;
		534	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
		535
		536	=item counter $seconds
		537
		538	Like C<again>, but also returns an increasing counter value, starting at
		539	0, which might be useful for some simple animation effects.
		540
		541	=cut
		542
		543	sub now() { urxvt::NOW }
		544
		545	sub again($) {
		546	$frame->[FR_AGAIN]{time} = $_[0];
		547	}
		548
		549	sub counter($) {
		550	$frame->[FR_AGAIN]{time} = $_[0];
		551	$frame->[FR_STATE]{counter} + 0
		552	}
		553
		554	=back
		555
		556	=head2 SHAPE CHANGING OPERATORS
		557
		558	The following operators modify the shape, size or position of the image.
		559
		560	=over 4
		561
		562	=item clip $img
		563
		564	=item clip $width, $height, $img
		565
		566	=item clip $x, $y, $width, $height, $img
		567
		568	Clips an image to the given rectangle. If the rectangle is outside the
		569	image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is
		570	larger than the image, then the tiling mode defines how the extra pixels
		571	will be filled.
		572
		573	If C<$x> an C<$y> are missing, then C<0> is assumed for both.
		574
		575	If C<$width> and C<$height> are missing, then the window size will be
		576	assumed.
		577
		578	Example: load an image, blur it, and clip it to the window size to save
		579	memory.
		580
		581	clip keep { blur 10, load "mybg.png" }
		582
		583	=cut
		584
46	sub clip($$$$$;$) {	585	sub clip($;$$;$$) {
47	my $img = pop;	586	my $img = pop;
		587	my $h = pop \|\| TH;
		588	my $w = pop \|\| TW;
48	$img->sub_rect ($_[0], $_[1], $_[2], $_[3], $_[4])	589	$img->sub_rect ($_[0], $_[1], $w, $h)
		590	}
		591
		592	=item scale $img
		593
		594	=item scale $size_factor, $img
		595
		596	=item scale $width_factor, $height_factor, $img
		597
		598	Scales the image by the given factors in horizontal
		599	(C<$width>) and vertical (C<$height>) direction.
		600
		601	If only one factor is give, it is used for both directions.
		602
		603	If no factors are given, scales the image to the window size without
		604	keeping aspect.
		605
		606	=item resize $width, $height, $img
		607
		608	Resizes the image to exactly C<$width> times C<$height> pixels.
		609
		610	=item fit $img
		611
		612	=item fit $width, $height, $img
		613
		614	Fits the image into the given C<$width> and C<$height> without changing
		615	aspect, or the terminal size. That means it will be shrunk or grown until
		616	the whole image fits into the given area, possibly leaving borders.
		617
		618	=item cover $img
		619
		620	=item cover $width, $height, $img
		621
		622	Similar to C<fit>, but shrinks or grows until all of the area is covered
		623	by the image, so instead of potentially leaving borders, it will cut off
		624	image data that doesn't fit.
		625
		626	=cut
		627
		628	sub scale($;$;$) {
		629	my $img = pop;
		630
		631	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
		632	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
		633	: $img->scale (TW, TH)
49	}	634	}
50		635
51	sub resize($$$) {	636	sub resize($$$) {
52	my $img = pop;	637	my $img = pop;
53	$img->scale ($_[0], $_[1])	638	$img->scale ($_[0], $_[1])
54	}	639	}
55		640
56	# TODO: ugly	641	sub fit($;$$) {
		642	my $img = pop;
		643	my $w = ($_[0] \|\| TW) / $img->w;
		644	my $h = ($_[1] \|\| TH) / $img->h;
		645	scale +(min $w, $h), $img
		646	}
		647
		648	sub cover($;$$) {
		649	my $img = pop;
		650	my $w = ($_[0] \|\| TW) / $img->w;
		651	my $h = ($_[1] \|\| TH) / $img->h;
		652	scale +(max $w, $h), $img
		653	}
		654
		655	=item move $dx, $dy, $img
		656
		657	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
		658	the vertical.
		659
		660	Example: move the image right by 20 pixels and down by 30.
		661
		662	move 20, 30, ...
		663
		664	=item align $xalign, $yalign, $img
		665
		666	Aligns the image according to a factor - C<0> means the image is moved to
		667	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		668	exactly centered and C<1> means it touches the right or bottom edge.
		669
		670	Example: remove any visible border around an image, center it vertically but move
		671	it to the right hand side.
		672
		673	align 1, 0.5, pad $img
		674
		675	=item center $img
		676
		677	=item center $width, $height, $img
		678
		679	Centers the image, i.e. the center of the image is moved to the center of
		680	the terminal window (or the box specified by C<$width> and C<$height> if
		681	given).
		682
		683	Example: load an image and center it.
		684
		685	center keep { pad load "mybg.png" }
		686
		687	=item rootalign $img
		688
		689	Moves the image so that it appears glued to the screen as opposed to the
		690	window. This gives the illusion of a larger area behind the window. It is
		691	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
		692	top left of the screen.
		693
		694	Example: load a background image, put it in mirror mode and root align it.
		695
		696	rootalign keep { mirror load "mybg.png" }
		697
		698	Example: take the screen background and align it, giving the illusion of
		699	transparency as long as the window isn't in front of other windows.
		700
		701	rootalign root
		702
		703	=cut
		704
57	sub move($$;$) {	705	sub move($$;$) {
		706	my $img = pop->clone;
		707	$img->move ($_[0], $_[1]);
		708	$img
		709	}
		710
		711	sub align($;$$) {
58	my $img = pop;	712	my $img = pop;
59	$img->sub_rect (
60	$_[0], $_[1],
61	$img->w, $img->h,
62	$_[2],
63	)
64	}
65		713
		714	move $_[0] * (TW - $img->w),
		715	$_[1] * (TH - $img->h),
		716	$img
		717	}
		718
		719	sub center($;$$) {
		720	my $img = pop;
		721	my $w = $_[0] \|\| TW;
		722	my $h = $_[1] \|\| TH;
		723
		724	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		725	}
		726
		727	sub rootalign($) {
		728	move -TX, -TY, $_[0]
		729	}
		730
		731	=item rotate $center_x, $center_y, $degrees, $img
		732
		733	Rotates the image clockwise by C<$degrees> degrees, around the point at
		734	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		735
		736	Example: rotate the image by 90 degrees around it's center.
		737
		738	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		739
		740	=cut
		741
66	sub rotate($$$$$$;$) {	742	sub rotate($$$$) {
67	my $img = pop;	743	my $img = pop;
68	$img->rotate (	744	$img->rotate (
69	$_[0],	745	$_[0] * ($img->w + $img->x),
70	$_[1],	746	$_[1] * ($img->h + $img->y),
71	$_[2] * $img->w * .01,
72	$_[3] * $img->h * .01,
73	$_[4] * (3.14159265 / 180),	747	$_[2] * (3.14159265 / 180),
74	$_[5],
75	)	748	)
76	}	749	}
77		750
78	sub blur($$$) {	751	=back
79	my ($rh, $rv, $img) = @_;
80		752
81	$img->blur ($rh, $rv);	753	=head2 COLOUR MODIFICATIONS
82	}	754
		755	The following operators change the pixels of the image.
		756
		757	=over 4
		758
		759	=item contrast $factor, $img
		760
		761	=item contrast $r, $g, $b, $img
		762
		763	=item contrast $r, $g, $b, $a, $img
		764
		765	Adjusts the I<contrast> of an image.
		766
		767	The first form applies a single C<$factor> to red, green and blue, the
		768	second form applies separate factors to each colour channel, and the last
		769	form includes the alpha channel.
		770
		771	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		772	contrast.
		773
		774	Due to limitations in the underlying XRender extension, lowering contrast
		775	also reduces brightness, while increasing contrast currently also
		776	increases brightness.
		777
		778	=item brightness $bias, $img
		779
		780	=item brightness $r, $g, $b, $img
		781
		782	=item brightness $r, $g, $b, $a, $img
		783
		784	Adjusts the brightness of an image.
		785
		786	The first form applies a single C<$bias> to red, green and blue, the
		787	second form applies separate biases to each colour channel, and the last
		788	form includes the alpha channel.
		789
		790	Values less than 0 reduce brightness, while values larger than 0 increase
		791	it. Useful range is from -1 to 1 - the former results in a black, the
		792	latter in a white picture.
		793
		794	Due to idiosyncrasies in the underlying XRender extension, biases less
		795	than zero can be I<very> slow.
		796
		797	=cut
83		798
84	sub contrast($$;$$;$) {	799	sub contrast($$;$$;$) {
85	my $img = pop;	800	my $img = pop;
86	my ($r, $g, $b, $a) = @_;	801	my ($r, $g, $b, $a) = @_;
87		802
88	($g, $b) = ($r, $r) if @_ < 4;	803	($g, $b) = ($r, $r) if @_ < 3;
89	$a = 1 if @_ < 5;	804	$a = 1 if @_ < 4;
90		805
91	$img = $img->clone;	806	$img = $img->clone;
92	$img->contrast ($r, $g, $b, $a);	807	$img->contrast ($r, $g, $b, $a);
93	$img	808	$img
94	}	809	}
95		810
96	sub brightness($$;$$;$) {	811	sub brightness($$;$$;$) {
97	my $img = pop;	812	my $img = pop;
98	my ($r, $g, $b, $a) = @_;	813	my ($r, $g, $b, $a) = @_;
99		814
100	($g, $b) = ($r, $r) if @_ < 4;	815	($g, $b) = ($r, $r) if @_ < 3;
101	$a = 1 if @_ < 5;	816	$a = 1 if @_ < 4;
102		817
103	$img = $img->clone;	818	$img = $img->clone;
104	$img->brightness ($r, $g, $b, $a);	819	$img->brightness ($r, $g, $b, $a);
105	$img	820	$img
106	}	821	}
107		822
108	sub X() { $new->{position_sensitive} = 1; $l }	823	=item blur $radius, $img
109	sub Y() { $new->{position_sensitive} = 1; $t }
110	sub W() { $new->{size_sensitive} = 1; $w }
111	sub H() { $new->{size_sensitive} = 1; $h }
112		824
113	sub now() { urxvt::NOW }	825	=item blur $radius_horz, $radius_vert, $img
114		826
115	sub again($) {	827	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
116	$new->{again} = $_[0];	828	can also be specified separately.
		829
		830	Blurring is often I<very> slow, at least compared or other
		831	operators. Larger blur radii are slower than smaller ones, too, so if you
		832	don't want to freeze your screen for long times, start experimenting with
		833	low values for radius (<5).
		834
		835	=cut
		836
		837	sub blur($$;$) {
		838	my $img = pop;
		839	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
		840	}
		841
		842	=back
		843
		844	=head2 OTHER STUFF
		845
		846	Anything that didn't fit any of the other categories, even after applying
		847	force and closing our eyes.
		848
		849	=over 4
		850
		851	=item keep { ... }
		852
		853	This operator takes a code block as argument, that is, one or more
		854	statements enclosed by braces.
		855
		856	The trick is that this code block is only evaluated when the outcome
		857	changes - on other calls the C<keep> simply returns the image it computed
		858	previously (yes, it should only be used with images). Or in other words,
		859	C<keep> I<caches> the result of the code block so it doesn't need to be
		860	computed again.
		861
		862	This can be extremely useful to avoid redoing slow operations - for
		863	example, if your background expression takes the root background, blurs it
		864	and then root-aligns it it would have to blur the root background on every
		865	window move or resize.
		866
		867	Another example is C<load>, which can be quite slow.
		868
		869	In fact, urxvt itself encloses the whole expression in some kind of
		870	C<keep> block so it only is reevaluated as required.
		871
		872	Putting the blur into a C<keep> block will make sure the blur is only done
		873	once, while the C<rootalign> is still done each time the window moves.
		874
		875	rootlign keep { blur 10, root }
		876
		877	This leaves the question of how to force reevaluation of the block,
		878	in case the root background changes: If expression inside the block
		879	is sensitive to some event (root background changes, window geometry
		880	changes), then it will be reevaluated automatically as needed.
		881
		882	=cut
		883
		884	sub keep(&) {
		885	my $id = $_[0]+0;
		886
		887	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		888
		889	unless ($frame->[FR_CACHE]) {
		890	$frame->[FR_CACHE] = [ $_[0]() ];
		891
		892	my $self = $self;
		893	my $frame = $frame;
		894	Scalar::Util::weaken $frame;
		895	$self->compile_frame ($frame, sub {
		896	# clear this frame cache, also for all parents
		897	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		898	undef $frame->[FR_CACHE];
		899	}
		900
		901	$self->recalculate;
		902	});
		903	};
		904
		905	# in scalar context we always return the first original result, which
		906	# is not quite how perl works.
		907	wantarray
		908	? @{ $frame->[FR_CACHE] }
		909	: $frame->[FR_CACHE][0]
		910	}
		911
		912	# sub keep_clear() {
		913	# delete $self->{frame_cache};
117	}	914	# }
118		915
119	sub counter($) {	916	=back
120	$new->{again} = $_[0];	917
121	$bgdsl_self->{counter} + 0	918	=cut
122	}	919
123	}	920	}
124		921
125	sub parse_expr {	922	sub parse_expr {
126	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	923	my $expr = eval
		924	"sub {\n"
		925	. "package urxvt::bgdsl;\n"
		926	. "#line 0 'background expression'\n"
		927	. "$_[0]\n"
		928	. "}";
127	die if $@;	929	die if $@;
128	$expr	930	$expr
129	}	931	}
130		932
131	# compiles a parsed expression	933	# compiles a parsed expression
132	sub set_expr {	934	sub set_expr {
133	my ($self, $expr) = @_;	935	my ($self, $expr) = @_;
134		936
		937	$self->{root} = [];
135	$self->{expr} = $expr;	938	$self->{expr} = $expr;
136	$self->recalculate;	939	$self->recalculate;
137	}	940	}
138		941
		942	# takes a hash of sensitivity indicators and installs watchers
		943	sub compile_frame {
		944	my ($self, $frame, $cb) = @_;
		945
		946	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		947	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		948
		949	# don't keep stuff alive
		950	Scalar::Util::weaken $state;
		951
		952	if ($again->{nested}) {
		953	$state->{nested} = 1;
		954	} else {
		955	delete $state->{nested};
		956	}
		957
		958	if (my $interval = $again->{time}) {
		959	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		960	if $state->{time}[0] != $interval;
		961
		962	# callback might have changed, although we could just rule that out
		963	$state->{time}[1]->cb (sub {
		964	++$state->{counter};
		965	$cb->();
		966	});
		967	} else {
		968	delete $state->{time};
		969	}
		970
		971	if ($again->{position}) {
		972	$state->{position} = $self->on (position_change => $cb);
		973	} else {
		974	delete $state->{position};
		975	}
		976
		977	if ($again->{size}) {
		978	$state->{size} = $self->on (size_change => $cb);
		979	} else {
		980	delete $state->{size};
		981	}
		982
		983	if ($again->{rootpmap}) {
		984	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		985	} else {
		986	delete $state->{rootpmap};
		987	}
		988	}
		989
139	# evaluate the current bg expression	990	# evaluate the current bg expression
140	sub recalculate {	991	sub recalculate {
141	my ($self) = @_;	992	my ($arg_self) = @_;
142		993
143	# rate limit evaluation	994	# rate limit evaluation
144		995
145	if ($self->{next_refresh} > urxvt::NOW) {	996	if ($arg_self->{next_refresh} > urxvt::NOW) {
146	$self->{next_refresh_timer} = urxvt::timer->new->after ($self->{next_refresh} - urxvt::NOW)->cb (sub {	997	$arg_self->{next_refresh_timer} = urxvt::timer->new->after ($arg_self->{next_refresh} - urxvt::NOW)->cb (sub {
147	$self->recalculate;	998	$arg_self->recalculate;
148	});	999	});
149	return;	1000	return;
150	}	1001	}
151		1002
152	$self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1003	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
153		1004
154	# set environment to evaluate user expression	1005	# set environment to evaluate user expression
155		1006
156	local $bgdsl_self = $self;	1007	local $self = $arg_self;
		1008	local $HOME = $ENV{HOME};
		1009	local $frame = [];
157		1010
158	local $old = $self->{state};	1011	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
159	local $new = my $state = $self->{state} = {};
160
161	($l, $t, $w, $h) =
162	$self->get_geometry;
163		1012
164	# evaluate user expression	1013	# evaluate user expression
165		1014
166	my $img = eval { $self->{expr}->() };	1015	my @img = eval { $self->{expr}->() };
167	warn $@ if $@;#d#	1016	die $@ if $@;
		1017	die "background-expr did not return anything.\n" unless @img;
		1018	die "background-expr: expected image(s), got something else.\n"
		1019	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
		1020
		1021	my $img = urxvt::bgdsl::merge @img;
		1022
		1023	$frame->[FR_AGAIN]{size} = 1
		1024	if $img->repeat_mode != urxvt::RepeatNormal;
168		1025
169	# if the expression is sensitive to external events, prepare reevaluation then	1026	# if the expression is sensitive to external events, prepare reevaluation then
170		1027	$self->compile_frame ($frame, sub { $arg_self->recalculate });
171	my $repeat;
172
173	if (my $again = $state->{again}) {
174	$repeat = 1;
175	$state->{timer} = $again == $old->{again}
176	? $old->{timer}
177	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
178	++$self->{counter};
179	$self->recalculate
180	});
181	}
182
183	if (delete $state->{position_sensitive}) {
184	$repeat = 1;
185	$self->enable (position_change => sub { $_[0]->recalculate });
186	} else {
187	$self->disable ("position_change");
188	}
189
190	if (delete $state->{size_sensitive}) {
191	$repeat = 1;
192	$self->enable (size_change => sub { $_[0]->recalculate });
193	} else {
194	$self->disable ("size_change");
195	}
196
197	if (delete $state->{rootpmap_sensitive}) {
198	$repeat = 1;
199	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
200	} else {
201	$self->disable ("rootpmap_change");
202	}
203		1028
204	# clear stuff we no longer need	1029	# clear stuff we no longer need
205		1030
206	%$old = ();	1031	# unless (%{ $frame->[FR_STATE] }) {
207
208	unless ($repeat) {
209	delete $self->{state};	1032	# delete $self->{state};
210	delete $self->{expr};	1033	# delete $self->{expr};
211	}	1034	# }
212		1035
213	# prepare and set background pixmap	1036	# set background pixmap
214		1037
215	$img = $img->sub_rect (0, 0, $w, $h)
216	if $img->w != $w \|\| $img->h != $h;
217
218	$self->set_background ($img);	1038	$self->set_background ($img, $self->{border});
219	$self->scr_recolour (0);	1039	$self->scr_recolour (0);
220	$self->want_refresh;	1040	$self->want_refresh;
221	}	1041	}
222		1042
223	sub on_start {	1043	sub on_start {
224	my ($self) = @_;	1044	my ($self) = @_;
225		1045
		1046	my $expr = $self->x_resource ("%.expr")
		1047	or return;
		1048
		1049	$self->has_render
		1050	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1051
226	$self->set_expr (parse_expr $EXPR);	1052	$self->set_expr (parse_expr $expr);
		1053	$self->{border} = $self->x_resource_boolean ("%.border");
		1054
		1055	$MIN_INTERVAL = $self->x_resource ("%.interval");
227		1056
228	()	1057	()
229	}	1058	}
230		1059

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.13 by root, Tue Jun 5 19:32:29 2012 UTC vs. Revision 1.68 by root, Sun Jul 1 21:47:07 2012 UTC

Diff Legend

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.13 by root, Tue Jun 5 19:32:29 2012 UTC vs.
Revision 1.68 by root, Sun Jul 1 21:47:07 2012 UTC