[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 1.67 by sf-exg, Fri Jun 29 18:12:25 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 expression is evaluated once per hour. It will set F<sunday.png> as
		79	background on Sundays, and F<weekday.png> on all other days.
		80
		81	Fortunately, we expect that most expressions will be much simpler, with
		82	little Perl knowledge needed.
		83
		84	Basically, you always start with a function that "generates" an image
		85	object, such as C<load>, which loads an image from disk, or C<root>, which
		86	returns the root window background image:
		87
		88	load "$HOME/mypic.png"
		89
		90	The path is usually specified as a quoted string (the exact rules can be
		91	found in the L<perlop> manpage). The F<$HOME> at the beginning of the
		92	string is expanded to the home directory.
		93
		94	Then you prepend one or more modifiers or filtering expressions, such as
		95	C<scale>:
		96
		97	scale load "$HOME/mypic.png"
		98
		99	Just like a mathematical expression with functions, you should read these
		100	expressions from right to left, as the C<load> is evaluated first, and
		101	its result becomes the argument to the C<scale> function.
		102
		103	Many operators also allow some parameters preceding the input image
		104	that modify its behaviour. For example, C<scale> without any additional
		105	arguments scales the image to size of the terminal window. If you specify
		106	an additional argument, it uses it as a scale factor (multiply by 100 to
		107	get a percentage):
		108
		109	scale 2, load "$HOME/mypic.png"
		110
		111	This enlarges the image by a factor of 2 (200%). As you can see, C<scale>
		112	has now two arguments, the C<200> and the C<load> expression, while
		113	C<load> only has one argument. Arguments are separated from each other by
		114	commas.
		115
		116	Scale also accepts two arguments, which are then separate factors for both
		117	horizontal and vertical dimensions. For example, this halves the image
		118	width and doubles the image height:
		119
		120	scale 0.5, 2, load "$HOME/mypic.png"
		121
		122	IF you try out these expressions, you might suffer from sluggishness,
		123	because each time the terminal is resized, it again loads the PNG image
		124	and scales it. Scaling is usually fast, but loading the image can be quite
		125	time consuming. This is where C<keep> comes in handy:
		126
		127	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		128
		129	The C<keep> operator executes all the statements inside the braces only
		130	once, or when it thinks the outcome might change. In other cases it
		131	returns the last value computed by the brace block.
		132
		133	This means that the C<load> is only executed once, which makes it much
		134	faster, but also means that more memory is being used, because the loaded
		135	image must be kept in memory at all times. In this expression, the
		136	trade-off is likely worth it.
		137
		138	But back to effects: Other effects than scaling are also readily
		139	available, for example, you can tile the image to fill the whole window,
		140	instead of resizing it:
		141
		142	tile keep { load "$HOME/mypic.png" }
		143
		144	In fact, images returned by C<load> are in C<tile> mode by default, so the
		145	C<tile> operator is kind of superfluous.
		146
		147	Another common effect is to mirror the image, so that the same edges
		148	touch:
		149
		150	mirror keep { load "$HOME/mypic.png" }
		151
		152	Another common background expression is:
		153
		154	rootalign root
		155
		156	This one first takes a snapshot of the screen background image, and then
		157	moves it to the upper left corner of the screen (as opposed to the upper
		158	left corner of the terminal window)- the result is pseudo-transparency:
		159	the image seems to be static while the window is moved around.
		160
		161	=head2 CACHING AND SENSITIVITY
		162
		163	Since some operations (such as C<load> and C<blur>) can take a long time,
		164	caching results can be very important for a smooth operation. Caching can
		165	also be useful to reduce memory usage, though, for example, when an image
		166	is cached by C<load>, it could be shared by multiple terminal windows
		167	running inside urxvtd.
		168
		169	=head3 C<keep { ... }> caching
		170
		171	The most important way to cache expensive operations is to use C<keep {
		172	... }>. The C<keep> operator takes a block of multiple statements enclosed
		173	by C<{}> and keeps the return value in memory.
		174
		175	An expression can be "sensitive" to various external events, such as
		176	scaling or moving the window, root background changes and timers. Simply
		177	using an expression (such as C<scale> without parameters) that depends on
		178	certain changing values (called "variables"), or using those variables
		179	directly, will make an expression sensitive to these events - for example,
		180	using C<scale> or C<TW> will make the expression sensitive to the terminal
		181	size, and thus to resizing events.
		182
		183	When such an event happens, C<keep> will automatically trigger a
		184	reevaluation of the whole expression with the new value of the expression.
		185
		186	C<keep> is most useful for expensive operations, such as C<blur>:
		187
		188	rootalign once { blur 20, root }
		189
		190	This makes a blurred copy of the root background once, and on subsequent
		191	calls, just root-aligns it. Since C<blur> is usually quite slow and
		192	C<rootalign> is quite fast, this trades extra memory (for the cached
		193	blurred pixmap) with speed (blur only needs to be redone when root
		194	changes).
		195
		196	=head3 C<load> caching
		197
		198	The C<load> operator itself does not keep images in memory, but as long as
		199	the image is still in memory, C<load> will use the in-memory image instead
		200	of loading it freshly from disk.
		201
		202	That means that this expression:
		203
		204	keep { load "$HOME/path..." }
		205
		206	Not only caches the image in memory, other terminal instances that try to
		207	C<load> it can reuse that in-memory copy.
		208
		209	=head1 REFERENCE
		210
		211	=head2 COMMAND LINE SWITCHES
		212
		213	=over 4
		214
		215	=item --background-expr perl-expression
		216
		217	Specifies the Perl expression to evaluate.
		218
		219	=item --background-border
		220
		221	By default, the expression creates an image that fills the full window,
		222	overwriting borders and any other areas, such as the scrollbar.
		223
		224	Specifying this flag changes the behaviour, so that the image only
		225	replaces the background of the character area.
		226
		227	=item --background-interval seconds
		228
		229	Since some operations in the underlying XRender extension can effectively
		230	freeze your X-server for prolonged time, this extension enforces a minimum
		231	time between updates, which is normally about 0.1 seconds.
		232
		233	If you want to do updates more often, you can decrease this safety
		234	interval with this switch.
		235
		236	=back
		237
		238	=cut
		239
		240	our %_IMG_CACHE;
		241	our $HOME;
		242	our ($self, $frame);
18	our ($l, $t, $w, $h);	243	our ($x, $y, $w, $h);
19		244
20	# enforce at leats this time between updates	245	# enforce at least this interval between updates
21	our $MIN_INTERVAL = 1/100;	246	our $MIN_INTERVAL = 6/59.951;
22		247
23	{	248	{
24	package urxvt::bgdsl; # background language	249	package urxvt::bgdsl; # background language
25		250
26	*repeat_black = \&urxvt::RepeatNone; #TODO wtf	251	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
27	*repeat_wrap = \&urxvt::RepeatNormal;	252	sub FR_CACHE () { 1 } # cached values
28	*repeat_pad = \&urxvt::RepeatPad;	253	sub FR_AGAIN () { 2 } # what this expr is sensitive to
29	*repeat_mirror = \&urxvt::RepeatReflect;	254	sub FR_STATE () { 3 } # watchers etc.
		255
		256	use List::Util qw(min max sum shuffle);
		257
		258	=head2 PROVIDERS/GENERATORS
		259
		260	These functions provide an image, by loading it from disk, grabbing it
		261	from the root screen or by simply generating it. They are used as starting
		262	points to get an image you can play with.
		263
		264	=over 4
		265
		266	=item load $path
		267
		268	Loads the image at the given C<$path>. The image is set to plane tiling
		269	mode.
		270
		271	If the image is already in memory (e.g. because another terminal instance
		272	uses it), then the in-memory copy us returned instead.
		273
		274	=item load_uc $path
		275
		276	Load uncached - same as load, but does not cache the image, which means it
		277	is I<always> loaded from the filesystem again.
		278
		279	=cut
		280
		281	sub load_uc($) {
		282	$self->new_img_from_file ($path)
		283	}
30		284
31	sub load($) {	285	sub load($) {
32	my ($path) = @_;	286	my ($path) = @_;
33		287
34	$new->{load}{$path} = $old->{load}{$path} \|\| $bgdsl_self->new_img_from_file ($path);	288	$_IMG_CACHE{$path} \|\| do {
		289	my $img = load_uc $path;
		290	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		291	$img
		292	}
35	}	293	}
		294
		295	=item root
		296
		297	Returns the root window pixmap, that is, hopefully, the background image
		298	of your screen.
		299
		300	This function makes your expression root sensitive, that means it will be
		301	reevaluated when the bg image changes.
		302
		303	=cut
36		304
37	sub root() {	305	sub root() {
38	$new->{rootpmap_sensitive} = 1;	306	$frame->[FR_AGAIN]{rootpmap} = 1;
39	die "root op not supported, exg, we need you";	307	$self->new_img_from_root
40	}	308	}
41		309
		310	=item solid $colour
		311
		312	=item solid $width, $height, $colour
		313
		314	Creates a new image and completely fills it with the given colour. The
		315	image is set to tiling mode.
		316
		317	If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
		318	useful for solid backgrounds or for use in filtering effects.
		319
		320	=cut
		321
		322	sub solid($;$$) {
		323	my $colour = pop;
		324
		325	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
		326	$img->fill ($colour);
		327	$img
		328	}
		329
		330	=item clone $img
		331
		332	Returns an exact copy of the image. This is useful if you want to have
		333	multiple copies of the same image to apply different effects to.
		334
		335	=cut
		336
42	# sub clone($) {	337	sub clone($) {
43	# $_[0]->clone	338	$_[0]->clone
44	# }	339	}
45		340
		341	=item merge $img ...
		342
		343	Takes any number of images and merges them together, creating a single
		344	image containing them all. The tiling mode of the first image is used as
		345	the tiling mode of the resulting image.
		346
		347	This function is called automatically when an expression returns multiple
		348	images.
		349
		350	=cut
		351
		352	sub merge(@) {
		353	return $_[0] unless $#_;
		354
		355	# rather annoyingly clumsy, but optimisation is for another time
		356
		357	my $x0 = +1e9;
		358	my $y0 = +1e9;
		359	my $x1 = -1e9;
		360	my $y1 = -1e9;
		361
		362	for (@_) {
		363	my ($x, $y, $w, $h) = $_->geometry;
		364
		365	$x0 = $x if $x0 > $x;
		366	$y0 = $y if $y0 > $y;
		367
		368	$x += $w;
		369	$y += $h;
		370
		371	$x1 = $x if $x1 < $x;
		372	$y1 = $y if $y1 < $y;
		373	}
		374
		375	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		376	$base->repeat_mode ($_[0]->repeat_mode);
		377	$base->fill ([0, 0, 0, 0]);
		378
		379	$base->draw ($_)
		380	for @_;
		381
		382	$base
		383	}
		384
		385	=head2 TILING MODES
		386
		387	The following operators modify the tiling mode of an image, that is, the
		388	way that pixels outside the image area are painted when the image is used.
		389
		390	=over 4
		391
		392	=item tile $img
		393
		394	Tiles the whole plane with the image and returns this new image - or in
		395	other words, it returns a copy of the image in plane tiling mode.
		396
		397	Example: load an image and tile it over the background, without
		398	resizing. The C<tile> call is superfluous because C<load> already defaults
		399	to tiling mode.
		400
		401	tile load "mybg.png"
		402
		403	=item mirror $img
		404
		405	Similar to tile, but reflects the image each time it uses a new copy, so
		406	that top edges always touch top edges, right edges always touch right
		407	edges and so on (with normal tiling, left edges always touch right edges
		408	and top always touch bottom edges).
		409
		410	Example: load an image and mirror it over the background, avoiding sharp
		411	edges at the image borders at the expense of mirroring the image itself
		412
		413	mirror load "mybg.png"
		414
		415	=item pad $img
		416
		417	Takes an image and modifies it so that all pixels outside the image area
		418	become transparent. This mode is most useful when you want to place an
		419	image over another image or the background colour while leaving all
		420	background pixels outside the image unchanged.
		421
		422	Example: load an image and display it in the upper left corner. The rest
		423	of the space is left "empty" (transparent or whatever your compositor does
		424	in alpha mode, else background colour).
		425
		426	pad load "mybg.png"
		427
		428	=item extend $img
		429
		430	Extends the image over the whole plane, using the closest pixel in the
		431	area outside the image. This mode is mostly useful when you use more complex
		432	filtering operations and want the pixels outside the image to have the
		433	same values as the pixels near the edge.
		434
		435	Example: just for curiosity, how does this pixel extension stuff work?
		436
		437	extend move 50, 50, load "mybg.png"
		438
		439	=cut
		440
		441	sub pad($) {
		442	my $img = $_[0]->clone;
		443	$img->repeat_mode (urxvt::RepeatNone);
		444	$img
		445	}
		446
		447	sub tile($) {
		448	my $img = $_[0]->clone;
		449	$img->repeat_mode (urxvt::RepeatNormal);
		450	$img
		451	}
		452
		453	sub mirror($) {
		454	my $img = $_[0]->clone;
		455	$img->repeat_mode (urxvt::RepeatReflect);
		456	$img
		457	}
		458
		459	sub extend($) {
		460	my $img = $_[0]->clone;
		461	$img->repeat_mode (urxvt::RepeatPad);
		462	$img
		463	}
		464
		465	=back
		466
		467	=head2 VARIABLE VALUES
		468
		469	The following functions provide variable data such as the terminal window
		470	dimensions. They are not (Perl-) variables, they just return stuff that
		471	varies. Most of them make your expression sensitive to some events, for
		472	example using C<TW> (terminal width) means your expression is evaluated
		473	again when the terminal is resized.
		474
		475	=over 4
		476
		477	=item TX
		478
		479	=item TY
		480
		481	Return the X and Y coordinates of the terminal window (the terminal
		482	window is the full window by default, and the character area only when in
		483	border-respect mode).
		484
		485	Using these functions make your expression sensitive to window moves.
		486
		487	These functions are mainly useful to align images to the root window.
		488
		489	Example: load an image and align it so it looks as if anchored to the
		490	background (that's exactly what C<rootalign> does btw.):
		491
		492	move -TX, -TY, keep { load "mybg.png" }
		493
		494	=item TW
		495
		496	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		497	terminal window is the full window by default, and the character area only
		498	when in border-respect mode).
		499
		500	Using these functions make your expression sensitive to window resizes.
		501
		502	These functions are mainly useful to scale images, or to clip images to
		503	the window size to conserve memory.
		504
		505	Example: take the screen background, clip it to the window size, blur it a
		506	bit, align it to the window position and use it as background.
		507
		508	clip move -TX, -TY, keep { blur 5, root }
		509
		510	=cut
		511
		512	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
		513	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
		514	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
		515	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
		516
		517	=item now
		518
		519	Returns the current time as (fractional) seconds since the epoch.
		520
		521	Using this expression does I<not> make your expression sensitive to time,
		522	but the next two functions do.
		523
		524	=item again $seconds
		525
		526	When this function is used the expression will be reevaluated again in
		527	C<$seconds> seconds.
		528
		529	Example: load some image and rotate it according to the time of day (as if it were
		530	the hour pointer of a clock). Update this image every minute.
		531
		532	again 60;
		533	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
		534
		535	=item counter $seconds
		536
		537	Like C<again>, but also returns an increasing counter value, starting at
		538	0, which might be useful for some simple animation effects.
		539
		540	=cut
		541
		542	sub now() { urxvt::NOW }
		543
		544	sub again($) {
		545	$frame->[FR_AGAIN]{time} = $_[0];
		546	}
		547
		548	sub counter($) {
		549	$frame->[FR_AGAIN]{time} = $_[0];
		550	$frame->[FR_STATE]{counter} + 0
		551	}
		552
		553	=back
		554
		555	=head2 SHAPE CHANGING OPERATORS
		556
		557	The following operators modify the shape, size or position of the image.
		558
		559	=over 4
		560
		561	=item clip $img
		562
		563	=item clip $width, $height, $img
		564
		565	=item clip $x, $y, $width, $height, $img
		566
		567	Clips an image to the given rectangle. If the rectangle is outside the
		568	image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is
		569	larger than the image, then the tiling mode defines how the extra pixels
		570	will be filled.
		571
		572	If C<$x> an C<$y> are missing, then C<0> is assumed for both.
		573
		574	If C<$width> and C<$height> are missing, then the window size will be
		575	assumed.
		576
		577	Example: load an image, blur it, and clip it to the window size to save
		578	memory.
		579
		580	clip keep { blur 10, load "mybg.png" }
		581
		582	=cut
		583
46	sub clip($$$$$;$) {	584	sub clip($;$$;$$) {
47	my $img = pop;	585	my $img = pop;
		586	my $h = pop \|\| TH;
		587	my $w = pop \|\| TW;
48	$img->sub_rect ($_[0], $_[1], $_[2], $_[3], $_[4])	588	$img->sub_rect ($_[0], $_[1], $w, $h)
		589	}
		590
		591	=item scale $img
		592
		593	=item scale $size_factor, $img
		594
		595	=item scale $width_factor, $height_factor, $img
		596
		597	Scales the image by the given factors in horizontal
		598	(C<$width>) and vertical (C<$height>) direction.
		599
		600	If only one factor is give, it is used for both directions.
		601
		602	If no factors are given, scales the image to the window size without
		603	keeping aspect.
		604
		605	=item resize $width, $height, $img
		606
		607	Resizes the image to exactly C<$width> times C<$height> pixels.
		608
		609	=item fit $img
		610
		611	=item fit $width, $height, $img
		612
		613	Fits the image into the given C<$width> and C<$height> without changing
		614	aspect, or the terminal size. That means it will be shrunk or grown until
		615	the whole image fits into the given area, possibly leaving borders.
		616
		617	=item cover $img
		618
		619	=item cover $width, $height, $img
		620
		621	Similar to C<fit>, but shrinks or grows until all of the area is covered
		622	by the image, so instead of potentially leaving borders, it will cut off
		623	image data that doesn't fit.
		624
		625	=cut
		626
		627	sub scale($;$;$) {
		628	my $img = pop;
		629
		630	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
		631	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
		632	: $img->scale (TW, TH)
49	}	633	}
50		634
51	sub resize($$$) {	635	sub resize($$$) {
52	my $img = pop;	636	my $img = pop;
53	$img->scale ($_[0], $_[1])	637	$img->scale ($_[0], $_[1])
54	}	638	}
55		639
56	# TODO: ugly	640	sub fit($;$$) {
		641	my $img = pop;
		642	my $w = ($_[0] \|\| TW) / $img->w;
		643	my $h = ($_[1] \|\| TH) / $img->h;
		644	scale +(min $w, $h), $img
		645	}
		646
		647	sub cover($;$$) {
		648	my $img = pop;
		649	my $w = ($_[0] \|\| TW) / $img->w;
		650	my $h = ($_[1] \|\| TH) / $img->h;
		651	scale +(max $w, $h), $img
		652	}
		653
		654	=item move $dx, $dy, $img
		655
		656	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
		657	the vertical.
		658
		659	Example: move the image right by 20 pixels and down by 30.
		660
		661	move 20, 30, ...
		662
		663	=item align $xalign, $yalign, $img
		664
		665	Aligns the image according to a factor - C<0> means the image is moved to
		666	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		667	exactly centered and C<1> means it touches the right or bottom edge.
		668
		669	Example: remove any visible border around an image, center it vertically but move
		670	it to the right hand side.
		671
		672	align 1, 0.5, pad $img
		673
		674	=item center $img
		675
		676	=item center $width, $height, $img
		677
		678	Centers the image, i.e. the center of the image is moved to the center of
		679	the terminal window (or the box specified by C<$width> and C<$height> if
		680	given).
		681
		682	Example: load an image and center it.
		683
		684	center keep { pad load "mybg.png" }
		685
		686	=item rootalign $img
		687
		688	Moves the image so that it appears glued to the screen as opposed to the
		689	window. This gives the illusion of a larger area behind the window. It is
		690	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
		691	top left of the screen.
		692
		693	Example: load a background image, put it in mirror mode and root align it.
		694
		695	rootalign keep { mirror load "mybg.png" }
		696
		697	Example: take the screen background and align it, giving the illusion of
		698	transparency as long as the window isn't in front of other windows.
		699
		700	rootalign root
		701
		702	=cut
		703
57	sub move($$;$) {	704	sub move($$;$) {
		705	my $img = pop->clone;
		706	$img->move ($_[0], $_[1]);
		707	$img
		708	}
		709
		710	sub align($;$$) {
58	my $img = pop;	711	my $img = pop;
59	$img->sub_rect (
60	$_[0], $_[1],
61	$img->w, $img->h,
62	$_[2],
63	)
64	}
65		712
		713	move $_[0] * (TW - $img->w),
		714	$_[1] * (TH - $img->h),
		715	$img
		716	}
		717
		718	sub center($;$$) {
		719	my $img = pop;
		720	my $w = $_[0] \|\| TW;
		721	my $h = $_[1] \|\| TH;
		722
		723	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		724	}
		725
		726	sub rootalign($) {
		727	move -TX, -TY, $_[0]
		728	}
		729
		730	=item rotate $center_x, $center_y, $degrees, $img
		731
		732	Rotates the image clockwise by C<$degrees> degrees, around the point at
		733	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		734
		735	Example: rotate the image by 90 degrees around it's center.
		736
		737	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		738
		739	=cut
		740
66	sub rotate($$$$$$;$) {	741	sub rotate($$$$) {
67	my $img = pop;	742	my $img = pop;
68	$img->rotate (	743	$img->rotate (
69	$_[0],	744	$_[0] * ($img->w + $img->x),
70	$_[1],	745	$_[1] * ($img->h + $img->y),
71	$_[2] * $img->w * .01,
72	$_[3] * $img->h * .01,
73	$_[4] * (3.14159265 / 180),	746	$_[2] * (3.14159265 / 180),
74	$_[5],
75	)	747	)
76	}	748	}
77		749
78	sub blur($$$) {	750	=back
79	my ($rh, $rv, $img) = @_;
80		751
81	$img->blur ($rh, $rv);	752	=head2 COLOUR MODIFICATIONS
82	}	753
		754	The following operators change the pixels of the image.
		755
		756	=over 4
		757
		758	=item contrast $factor, $img
		759
		760	=item contrast $r, $g, $b, $img
		761
		762	=item contrast $r, $g, $b, $a, $img
		763
		764	Adjusts the I<contrast> of an image.
		765
		766	The first form applies a single C<$factor> to red, green and blue, the
		767	second form applies separate factors to each colour channel, and the last
		768	form includes the alpha channel.
		769
		770	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		771	contrast.
		772
		773	Due to limitations in the underlying XRender extension, lowering contrast
		774	also reduces brightness, while increasing contrast currently also
		775	increases brightness.
		776
		777	=item brightness $bias, $img
		778
		779	=item brightness $r, $g, $b, $img
		780
		781	=item brightness $r, $g, $b, $a, $img
		782
		783	Adjusts the brightness of an image.
		784
		785	The first form applies a single C<$bias> to red, green and blue, the
		786	second form applies separate biases to each colour channel, and the last
		787	form includes the alpha channel.
		788
		789	Values less than 0 reduce brightness, while values larger than 0 increase
		790	it. Useful range is from -1 to 1 - the former results in a black, the
		791	latter in a white picture.
		792
		793	Due to idiosyncrasies in the underlying XRender extension, biases less
		794	than zero can be I<very> slow.
		795
		796	=cut
83		797
84	sub contrast($$;$$;$) {	798	sub contrast($$;$$;$) {
85	my $img = pop;	799	my $img = pop;
86	my ($r, $g, $b, $a) = @_;	800	my ($r, $g, $b, $a) = @_;
87		801
88	($g, $b) = ($r, $r) if @_ < 4;	802	($g, $b) = ($r, $r) if @_ < 3;
89	$a = 1 if @_ < 5;	803	$a = 1 if @_ < 4;
90		804
91	$img = $img->clone;	805	$img = $img->clone;
92	$img->contrast ($r, $g, $b, $a);	806	$img->contrast ($r, $g, $b, $a);
93	$img	807	$img
94	}	808	}
95		809
96	sub brightness($$;$$;$) {	810	sub brightness($$;$$;$) {
97	my $img = pop;	811	my $img = pop;
98	my ($r, $g, $b, $a) = @_;	812	my ($r, $g, $b, $a) = @_;
99		813
100	($g, $b) = ($r, $r) if @_ < 4;	814	($g, $b) = ($r, $r) if @_ < 3;
101	$a = 1 if @_ < 5;	815	$a = 1 if @_ < 4;
102		816
103	$img = $img->clone;	817	$img = $img->clone;
104	$img->brightness ($r, $g, $b, $a);	818	$img->brightness ($r, $g, $b, $a);
105	$img	819	$img
106	}	820	}
107		821
108	sub X() { $new->{position_sensitive} = 1; $l }	822	=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		823
113	sub now() { urxvt::NOW }	824	=item blur $radius_horz, $radius_vert, $img
114		825
		826	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
		827	can also be specified separately.
		828
		829	Blurring is often I<very> slow, at least compared or other
		830	operators. Larger blur radii are slower than smaller ones, too, so if you
		831	don't want to freeze your screen for long times, start experimenting with
		832	low values for radius (<5).
		833
		834	=cut
		835
		836	sub blur($$;$) {
		837	my $img = pop;
		838	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
		839	}
		840
		841	=back
		842
		843	=head2 OTHER STUFF
		844
		845	Anything that didn't fit any of the other categories, even after applying
		846	force and closing our eyes.
		847
		848	=over 4
		849
		850	=item keep { ... }
		851
		852	#TODO#
		853
		854	This operator takes a code block as argument, that is, one or more
		855	statements enclosed by braces.
		856
		857	The trick is that this code block is only evaluated once - future calls
		858	will simply return the original image (yes, it should only be used with
		859	images).
		860
		861	This can be extremely useful to avoid redoing the same slow operations
		862	again and again- for example, if your background expression takes the root
		863	background, blurs it and then root-aligns it it would have to blur the
		864	root background on every window move or resize.
		865
		866	In fact, urxvt itself encloses the whole expression in some kind of
		867	C<once> block so it only is reevaluated as required.
		868
		869	Putting the blur into a C<once> block will make sure the blur is only done
		870	once:
		871
		872	rootlign keep { blur 10, root }
		873
		874	This leaves the question of how to force reevaluation of the block,
		875	in case the root background changes: If expression inside the block
		876	is sensitive to some event (root background changes, window geometry
		877	changes), then it will be reevaluated automatically as needed.
		878
		879	=item once_again
		880
		881	Resets all C<once> block as if they had never been called, i.e. on the
		882	next call they will be reevaluated again.
		883
		884	=cut
		885
		886	sub once(&) {
		887	my $id = $_[0]+0;
		888
		889	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		890
		891	unless ($frame->[FR_CACHE]) {
		892	$frame->[FR_CACHE] = [ $_[0]() ];
		893
		894	my $self = $self;
		895	my $frame = $frame;
		896	Scalar::Util::weaken $frame;
		897	$self->compile_frame ($frame, sub {
		898	# clear this frame cache, also for all parents
		899	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		900	undef $frame->[FR_CACHE];
		901	}
		902
		903	$self->recalculate;
		904	});
		905	};
		906
		907	# in scalar context we always return the first original result, which
		908	# is not quite how perl works.
		909	wantarray
		910	? @{ $frame->[FR_CACHE] }
		911	: $frame->[FR_CACHE][0]
		912	}
		913
115	sub again($) {	914	sub once_again() {
116	$new->{again} = $_[0];	915	delete $self->{frame_cache};
117	}	916	}
118		917
119	sub counter($) {	918	=back
120	$new->{again} = $_[0];	919
121	$bgdsl_self->{counter} + 0	920	=cut
122	}	921
123	}	922	}
124		923
125	sub parse_expr {	924	sub parse_expr {
126	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	925	my $expr = eval
		926	"sub {\n"
		927	. "package urxvt::bgdsl;\n"
		928	. "#line 0 'background expression'\n"
		929	. "$_[0]\n"
		930	. "}";
127	die if $@;	931	die if $@;
128	$expr	932	$expr
129	}	933	}
130		934
131	# compiles a parsed expression	935	# compiles a parsed expression
132	sub set_expr {	936	sub set_expr {
133	my ($self, $expr) = @_;	937	my ($self, $expr) = @_;
134		938
		939	$self->{root} = [];
135	$self->{expr} = $expr;	940	$self->{expr} = $expr;
136	$self->recalculate;	941	$self->recalculate;
137	}	942	}
138		943
		944	# takes a hash of sensitivity indicators and installs watchers
		945	sub compile_frame {
		946	my ($self, $frame, $cb) = @_;
		947
		948	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		949	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		950
		951	# don't keep stuff alive
		952	Scalar::Util::weaken $state;
		953
		954	if ($again->{nested}) {
		955	$state->{nested} = 1;
		956	} else {
		957	delete $state->{nested};
		958	}
		959
		960	if (my $interval = $again->{time}) {
		961	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		962	if $state->{time}[0] != $interval;
		963
		964	# callback might have changed, although we could just rule that out
		965	$state->{time}[1]->cb (sub {
		966	++$state->{counter};
		967	$cb->();
		968	});
		969	} else {
		970	delete $state->{time};
		971	}
		972
		973	if ($again->{position}) {
		974	$state->{position} = $self->on (position_change => $cb);
		975	} else {
		976	delete $state->{position};
		977	}
		978
		979	if ($again->{size}) {
		980	$state->{size} = $self->on (size_change => $cb);
		981	} else {
		982	delete $state->{size};
		983	}
		984
		985	if ($again->{rootpmap}) {
		986	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		987	} else {
		988	delete $state->{rootpmap};
		989	}
		990	}
		991
139	# evaluate the current bg expression	992	# evaluate the current bg expression
140	sub recalculate {	993	sub recalculate {
141	my ($self) = @_;	994	my ($arg_self) = @_;
142		995
143	# rate limit evaluation	996	# rate limit evaluation
144		997
145	if ($self->{next_refresh} > urxvt::NOW) {	998	if ($arg_self->{next_refresh} > urxvt::NOW) {
146	$self->{next_refresh_timer} = urxvt::timer->new->after ($self->{next_refresh} - urxvt::NOW)->cb (sub {	999	$arg_self->{next_refresh_timer} = urxvt::timer->new->after ($arg_self->{next_refresh} - urxvt::NOW)->cb (sub {
147	$self->recalculate;	1000	$arg_self->recalculate;
148	});	1001	});
149	return;	1002	return;
150	}	1003	}
151		1004
152	$self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1005	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
153		1006
154	# set environment to evaluate user expression	1007	# set environment to evaluate user expression
155		1008
156	local $bgdsl_self = $self;	1009	local $self = $arg_self;
		1010	local $HOME = $ENV{HOME};
		1011	local $frame = [];
157		1012
158	local $old = $self->{state};	1013	($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		1014
164	# evaluate user expression	1015	# evaluate user expression
165		1016
166	my $img = eval { $self->{expr}->() };	1017	my @img = eval { $self->{expr}->() };
167	warn $@ if $@;#d#	1018	die $@ if $@;
		1019	die "background-expr did not return anything.\n" unless @img;
		1020	die "background-expr: expected image(s), got something else.\n"
		1021	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
		1022
		1023	my $img = urxvt::bgdsl::merge @img;
		1024
		1025	$frame->[FR_AGAIN]{size} = 1
		1026	if $img->repeat_mode != urxvt::RepeatNormal;
168		1027
169	# if the expression is sensitive to external events, prepare reevaluation then	1028	# if the expression is sensitive to external events, prepare reevaluation then
170		1029	$self->compile_frame ($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	$self->disable ("rootpmap_change");
202	}
203		1030
204	# clear stuff we no longer need	1031	# clear stuff we no longer need
205		1032
206	%$old = ();	1033	# unless (%{ $frame->[FR_STATE] }) {
207
208	unless ($repeat) {
209	delete $self->{state};	1034	# delete $self->{state};
210	delete $self->{expr};	1035	# delete $self->{expr};
211	}	1036	# }
212		1037
213	# prepare and set background pixmap	1038	# set background pixmap
214		1039
215	$img = $img->sub_rect (0, 0, $w, $h)
216	if $img->w != $w \|\| $img->h != $h;
217
218	$self->set_background ($img);	1040	$self->set_background ($img, $self->{border});
219	$self->scr_recolour (0);	1041	$self->scr_recolour (0);
220	$self->want_refresh;	1042	$self->want_refresh;
221	}	1043	}
222		1044
223	sub on_start {	1045	sub on_start {
224	my ($self) = @_;	1046	my ($self) = @_;
225		1047
		1048	my $expr = $self->x_resource ("%.expr")
		1049	or return;
		1050
		1051	$self->has_render
		1052	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1053
226	$self->set_expr (parse_expr $EXPR);	1054	$self->set_expr (parse_expr $expr);
		1055	$self->{border} = $self->x_resource_boolean ("%.border");
		1056
		1057	$MIN_INTERVAL = $self->x_resource ("%.interval");
227		1058
228	()	1059	()
229	}	1060	}
230		1061

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.13 by root, Tue Jun 5 19:32:29 2012 UTC vs. Revision 1.67 by sf-exg, Fri Jun 29 18:12:25 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.13 by root, Tue Jun 5 19:32:29 2012 UTC vs.
Revision 1.67 by sf-exg, Fri Jun 29 18:12:25 2012 UTC