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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.23 by root, Thu Jun 7 10:22:55 2012 UTC vs.
Revision 1.63 by root, Tue Jun 19 18:17:56 2012 UTC

1	#! perl	1	#! perl
2		2
3	#:META:X_RESOURCE:%.expr:string:background expression	3	#:META:X_RESOURCE:%.expr:string:background expression
4	#:META:X_RESOURCE:%.enable:boolean:some boolean	4	#:META:X_RESOURCE:%.border:boolean:respect the terminal border
5	#:META:X_RESOURCE:%.extra.:value:extra config	5	#:META:X_RESOURCE:%.interval:seconds:minimum time between updates
6		6
7	our $EXPR = 'clip move -X, -Y, load "MagnoliaAlpha.png"';	7	=head1 NAME
8	#$EXPR = '
9	# rotate W, H, 50, 50, counter 1/59.95, repeat_mirror,
10	# clip X, Y, W, H, repeat_mirror,
11	# load "/root/pix/das_fette_schwein.jpg"
12	#';
13	#$EXPR = 'solid "red"';
14	#$EXPR = 'blur root, 10, 10'
15	#$EXPR = 'blur move (root, -x, -y), 5, 5'
16	#resize load "/root/pix/das_fette_schwein.jpg", w, h
17		8
18	use Safe;	9	background - manage terminal background
19		10
20	our ($bgdsl_self, $old, $new);	11	=head1 SYNOPSIS
		12
		13	urxvt --background-expr 'background expression'
		14	--background-border
		15	--background-interval seconds
		16
		17	=head1 DESCRIPTION
		18
		19	This extension manages the terminal background by creating a picture that
		20	is behind the text, replacing the normal background colour.
		21
		22	It does so by evaluating a Perl expression that I<calculates> the image on
		23	the fly, for example, by grabbing the root background or loading a file.
		24
		25	While the full power of Perl is available, the operators have been design
		26	to be as simple as possible.
		27
		28	For example, to load an image and scale it to the window size, you would
		29	use:
		30
		31	urxvt --background-expr 'scale load "/path/to/mybg.png"'
		32
		33	Or specified as a X resource:
		34
		35	URxvt.background-expr: scale load "/path/to/mybg.png"
		36
		37	=head1 THEORY OF OPERATION
		38
		39	At startup, just before the window is mapped for the first time, the
		40	expression is evaluated and must yield an image. The image is then
		41	extended as necessary to cover the whole terminal window, and is set as a
		42	background pixmap.
		43
		44	If the image contains an alpha channel, then it will be used as-is in
		45	visuals that support alpha channels (for example, for a compositing
		46	manager). In other visuals, the terminal background colour will be used to
		47	replace any transparency.
		48
		49	When the expression relies, directly or indirectly, on the window size,
		50	position, the root pixmap, or a timer, then it will be remembered. If not,
		51	then it will be removed.
		52
		53	If any of the parameters that the expression relies on changes (when the
		54	window is moved or resized, its position or size changes; when the root
		55	pixmap is replaced by another one the root background changes; or when the
		56	timer elapses), then the expression will be evaluated again.
		57
		58	For example, an expression such as C<scale load "$HOME/mybg.png"> scales the
		59	image to the window size, so it relies on the window size and will
		60	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	again 3600;
		70	if (localtime now)[6]) {
		71	return scale load "$HOME/weekday.png";
		72	} else {
		73	return scale load "$HOME/sunday.png";
		74	}
		75
		76	This expression is evaluated once per hour. It will set F<sunday.png> as
		77	background on Sundays, and F<weekday.png> on all other days.
		78
		79	Fortunately, we expect that most expressions will be much simpler, with
		80	little Perl knowledge needed.
		81
		82	Basically, you always start with a function that "generates" an image
		83	object, such as C<load>, which loads an image from disk, or C<root>, which
		84	returns the root window background image:
		85
		86	load "$HOME/mypic.png"
		87
		88	The path is usually specified as a quoted string (the exact rules can be
		89	found in the L<perlop> manpage). The F<$HOME> at the beginning of the
		90	string is expanded to the home directory.
		91
		92	Then you prepend one or more modifiers or filtering expressions, such as
		93	C<scale>:
		94
		95	scale load "$HOME/mypic.png"
		96
		97	Just like a mathematical expression with functions, you should read these
		98	expressions from right to left, as the C<load> is evaluated first, and
		99	its result becomes the argument to the C<scale> function.
		100
		101	Many operators also allow some parameters preceding the input image
		102	that modify its behaviour. For example, C<scale> without any additional
		103	arguments scales the image to size of the terminal window. If you specify
		104	an additional argument, it uses it as a scale factor (multiply by 100 to
		105	get a percentage):
		106
		107	scale 2, load "$HOME/mypic.png"
		108
		109	This enlarges the image by a factor of 2 (200%). As you can see, C<scale>
		110	has now two arguments, the C<200> and the C<load> expression, while
		111	C<load> only has one argument. Arguments are separated from each other by
		112	commas.
		113
		114	Scale also accepts two arguments, which are then separate factors for both
		115	horizontal and vertical dimensions. For example, this halves the image
		116	width and doubles the image height:
		117
		118	scale 0.5, 2, load "$HOME/mypic.png"
		119
		120	Other effects than scaling are also readily available, for example, you can
		121	tile the image to fill the whole window, instead of resizing it:
		122
		123	tile load "$HOME/mypic.png"
		124
		125	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator
		126	is kind of superfluous.
		127
		128	Another common effect is to mirror the image, so that the same edges touch:
		129
		130	mirror load "$HOME/mypic.png"
		131
		132	This is also a typical background expression:
		133
		134	rootalign root
		135
		136	It first takes a snapshot of the screen background image, and then
		137	moves it to the upper left corner of the screen - the result is
		138	pseudo-transparency, as the image seems to be static while the window is
		139	moved around.
		140
		141	=head2 CYCLES AND CACHING
		142
		143	=head3 C<load> et al.
		144
		145	As has been mentioned before, the expression might be evaluated multiple
		146	times. Each time the expression is reevaluated, a new cycle is said to
		147	have begun. Many operators cache their results till the next cycle.
		148
		149	For example, the C<load> operator keeps a copy of the image. If it is
		150	asked to load the same image on the next cycle it will not load it again,
		151	but return the cached copy.
		152
		153	This only works for one cycle though, so as long as you load the same
		154	image every time, it will always be cached, but when you load a different
		155	image, it will forget about the first one.
		156
		157	This allows you to either speed things up by keeping multiple images in
		158	memory, or conserve memory by loading images more often.
		159
		160	For example, you can keep two images in memory and use a random one like
		161	this:
		162
		163	my $img1 = load "img1.png";
		164	my $img2 = load "img2.png";
		165	(0.5 > rand) ? $img1 : $img2
		166
		167	Since both images are "loaded" every time the expression is evaluated,
		168	they are always kept in memory. Contrast this version:
		169
		170	my $path1 = "img1.png";
		171	my $path2 = "img2.png";
		172	load ((0.5 > rand) ? $path1 : $path2)
		173
		174	Here, a path is selected randomly, and load is only called for one image,
		175	so keeps only one image in memory. If, on the next evaluation, luck
		176	decides to use the other path, then it will have to load that image again.
		177
		178	=head3 C<once { ... }>
		179
		180	Another way to cache expensive operations is to use C<once { ... }>. The
		181	C<once> operator takes a block of multiple statements enclosed by C<{}>
		182	and evaluates it only.. once, returning any images the last statement
		183	returned. Further calls simply produce the values from the cache.
		184
		185	This is most useful for expensive operations, such as C<blur>:
		186
		187	rootalign once { blur 20, root }
		188
		189	This makes a blurred copy of the root background once, and on subsequent
		190	calls, just root-aligns it. Since C<blur> is usually quite slow and
		191	C<rootalign> is quite fast, this trades extra memory (For the cached
		192	blurred pixmap) with speed (blur only needs to be redone when root
		193	changes).
		194
		195	=head1 REFERENCE
		196
		197	=head2 COMMAND LINE SWITCHES
		198
		199	=over 4
		200
		201	=item --background-expr perl-expression
		202
		203	Specifies the Perl expression to evaluate.
		204
		205	=item --background-border
		206
		207	By default, the expression creates an image that fills the full window,
		208	overwriting borders and any other areas, such as the scrollbar.
		209
		210	Specifying this flag changes the behaviour, so that the image only
		211	replaces the background of the character area.
		212
		213	=item --background-interval seconds
		214
		215	Since some operations in the underlying XRender extension can effectively
		216	freeze your X-server for prolonged time, this extension enforces a minimum
		217	time between updates, which is normally about 0.1 seconds.
		218
		219	If you want to do updates more often, you can decrease this safety
		220	interval with this switch.
		221
		222	=back
		223
		224	=cut
		225
		226	our %_IMG_CACHE;
		227	our $HOME;
		228	our ($self, $frame);
21	our ($l, $t, $w, $h);	229	our ($x, $y, $w, $h);
22		230
23	# enforce at least this interval between updates	231	# enforce at least this interval between updates
24	our $MIN_INTERVAL = 1/100;	232	our $MIN_INTERVAL = 6/59.951;
25		233
26	{	234	{
27	package urxvt::bgdsl; # background language	235	package urxvt::bgdsl; # background language
28		236
29	# *repeat_empty = \&urxvt::RepeatNone;	237	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
30	# *repeat_tile = \&urxvt::RepeatNormal;	238	sub FR_CACHE () { 1 } # cached values
31	# *repeat_pad = \&urxvt::RepeatPad;	239	sub FR_AGAIN () { 2 } # what this expr is sensitive to
32	# *repeat_mirror = \&urxvt::RepeatReflect;	240	sub FR_STATE () { 3 } # watchers etc.
		241
		242	use List::Util qw(min max sum shuffle);
33		243
34	=head2 PROVIDERS/GENERATORS	244	=head2 PROVIDERS/GENERATORS
35		245
		246	These functions provide an image, by loading it from disk, grabbing it
		247	from the root screen or by simply generating it. They are used as starting
		248	points to get an image you can play with.
		249
36	=over 4	250	=over 4
37		251
38	=item load $path	252	=item load $path
		253
		254	Loads the image at the given C<$path>. The image is set to plane tiling
		255	mode.
		256
		257	Loaded images will be cached for one cycle, and shared between temrinals
		258	running in the same process (e.g. in C<urxvtd>).
		259
		260	#=item load_uc $path
		261	#
		262	#Load uncached - same as load, but does not cache the image. This function
		263	#is most useufl if you want to optimise a background expression in some
		264	#way.
39		265
40	=cut	266	=cut
41		267
42	sub load($) {	268	sub load($) {
43	my ($path) = @_;	269	my ($path) = @_;
44		270
45	$new->{load}{$path} = $old->{load}{$path} \|\| $bgdsl_self->new_img_from_file ($path);	271	$_IMG_CACHE{$path} \|\| do {
		272	my $img = $self->new_img_from_file ($path);
		273	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		274	$img
		275	}
46	}	276	}
		277
		278	=item root
		279
		280	Returns the root window pixmap, that is, hopefully, the background image
		281	of your screen.
		282
		283	This function makes your expression root sensitive, that means it will be
		284	reevaluated when the bg image changes.
		285
		286	=cut
47		287
48	sub root() {	288	sub root() {
49	$new->{rootpmap_sensitive} = 1;	289	$frame->[FR_AGAIN]{rootpmap} = 1;
50	die "root op not supported, exg, we need you";	290	$self->new_img_from_root
51	}	291	}
		292
		293	=item solid $colour
		294
		295	=item solid $width, $height, $colour
		296
		297	Creates a new image and completely fills it with the given colour. The
		298	image is set to tiling mode.
		299
		300	If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
		301	useful for solid backgrounds or for use in filtering effects.
		302
		303	=cut
52		304
53	sub solid($;$$) {	305	sub solid($;$$) {
		306	my $colour = pop;
		307
54	my $img = $bgdsl_self->new_img (urxvt::PictStandardARGB32, $_[1] \|\| 1, $_[2] \|\| 1);	308	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
55	$img->fill ($_[0]);	309	$img->fill ($colour);
56	$img	310	$img
57	}	311	}
58		312
		313	=item clone $img
		314
		315	Returns an exact copy of the image. This is useful if you want to have
		316	multiple copies of the same image to apply different effects to.
		317
		318	=cut
		319
		320	sub clone($) {
		321	$_[0]->clone
		322	}
		323
		324	=item merge $img ...
		325
		326	Takes any number of images and merges them together, creating a single
		327	image containing them all. The tiling mode of the first image is used as
		328	the tiling mdoe of the resulting image.
		329
		330	This function is called automatically when an expression returns multiple
		331	images.
		332
		333	=cut
		334
		335	sub merge(@) {
		336	return $_[0] unless $#_;
		337
		338	# rather annoyingly clumsy, but optimisation is for another time
		339
		340	my $x0 = +1e9;
		341	my $y0 = +1e9;
		342	my $x1 = -1e9;
		343	my $y1 = -1e9;
		344
		345	for (@_) {
		346	my ($x, $y, $w, $h) = $_->geometry;
		347
		348	$x0 = $x if $x0 > $x;
		349	$y0 = $y if $y0 > $y;
		350
		351	$x += $w;
		352	$y += $h;
		353
		354	$x1 = $x if $x1 < $x;
		355	$y1 = $y if $y1 < $y;
		356	}
		357
		358	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		359	$base->repeat_mode ($_[0]->repeat_mode);
		360	$base->fill ([0, 0, 0, 0]);
		361
		362	$base->draw ($_)
		363	for @_;
		364
		365	$base
		366	}
		367
		368	=head2 TILING MODES
		369
		370	The following operators modify the tiling mode of an image, that is, the
		371	way that pixels outside the image area are painted when the image is used.
		372
		373	=over 4
		374
		375	=item tile $img
		376
		377	Tiles the whole plane with the image and returns this new image - or in
		378	other words, it returns a copy of the image in plane tiling mode.
		379
		380	Example: load an image and tile it over the background, without
		381	resizing. The C<tile> call is superfluous because C<load> already defaults
		382	to tiling mode.
		383
		384	tile load "mybg.png"
		385
		386	=item mirror $img
		387
		388	Similar to tile, but reflects the image each time it uses a new copy, so
		389	that top edges always touch top edges, right edges always touch right
		390	edges and so on (with normal tiling, left edges always touch right edges
		391	and top always touch bottom edges).
		392
		393	Example: load an image and mirror it over the background, avoiding sharp
		394	edges at the image borders at the expense of mirroring the image itself
		395
		396	mirror load "mybg.png"
		397
		398	=item pad $img
		399
		400	Takes an image and modifies it so that all pixels outside the image area
		401	become transparent. This mode is most useful when you want to place an
		402	image over another image or the background colour while leaving all
		403	background pixels outside the image unchanged.
		404
		405	Example: load an image and display it in the upper left corner. The rest
		406	of the space is left "empty" (transparent or whatever your compositor does
		407	in alpha mode, else background colour).
		408
		409	pad load "mybg.png"
		410
		411	=item extend $img
		412
		413	Extends the image over the whole plane, using the closest pixel in the
		414	area outside the image. This mode is mostly useful when you use more complex
		415	filtering operations and want the pixels outside the image to have the
		416	same values as the pixels near the edge.
		417
		418	Example: just for curiosity, how does this pixel extension stuff work?
		419
		420	extend move 50, 50, load "mybg.png"
		421
		422	=cut
		423
		424	sub pad($) {
		425	my $img = $_[0]->clone;
		426	$img->repeat_mode (urxvt::RepeatNone);
		427	$img
		428	}
		429
		430	sub tile($) {
		431	my $img = $_[0]->clone;
		432	$img->repeat_mode (urxvt::RepeatNormal);
		433	$img
		434	}
		435
		436	sub mirror($) {
		437	my $img = $_[0]->clone;
		438	$img->repeat_mode (urxvt::RepeatReflect);
		439	$img
		440	}
		441
		442	sub extend($) {
		443	my $img = $_[0]->clone;
		444	$img->repeat_mode (urxvt::RepeatPad);
		445	$img
		446	}
		447
59	=back	448	=back
60		449
61	=head2 VARIABLES	450	=head2 VARIABLE VALUES
		451
		452	The following functions provide variable data such as the terminal window
		453	dimensions. They are not (Perl-) variables, they just return stuff that
		454	varies. Most of them make your expression sensitive to some events, for
		455	example using C<TW> (terminal width) means your expression is evaluated
		456	again when the terminal is resized.
62		457
63	=over 4	458	=over 4
64		459
65	=cut	460	=item TX
66		461
67	sub X() { $new->{position_sensitive} = 1; $l }	462	=item TY
68	sub Y() { $new->{position_sensitive} = 1; $t }	463
69	sub W() { $new->{size_sensitive} = 1; $w }	464	Return the X and Y coordinates of the terminal window (the terminal
70	sub H() { $new->{size_sensitive} = 1; $h }	465	window is the full window by default, and the character area only when in
		466	border-respect mode).
		467
		468	Using these functions make your expression sensitive to window moves.
		469
		470	These functions are mainly useful to align images to the root window.
		471
		472	Example: load an image and align it so it looks as if anchored to the
		473	background.
		474
		475	move -TX, -TY, load "mybg.png"
		476
		477	=item TW
		478
		479	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		480	terminal window is the full window by default, and the character area only
		481	when in border-respect mode).
		482
		483	Using these functions make your expression sensitive to window resizes.
		484
		485	These functions are mainly useful to scale images, or to clip images to
		486	the window size to conserve memory.
		487
		488	Example: take the screen background, clip it to the window size, blur it a
		489	bit, align it to the window position and use it as background.
		490
		491	clip move -TX, -TY, once { blur 5, root }
		492
		493	=cut
		494
		495	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
		496	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
		497	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
		498	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
		499
		500	=item now
		501
		502	Returns the current time as (fractional) seconds since the epoch.
		503
		504	Using this expression does I<not> make your expression sensitive to time,
		505	but the next two functions do.
		506
		507	=item again $seconds
		508
		509	When this function is used the expression will be reevaluated again in
		510	C<$seconds> seconds.
		511
		512	Example: load some image and rotate it according to the time of day (as if it were
		513	the hour pointer of a clock). Update this image every minute.
		514
		515	again 60; rotate 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
		516
		517	=item counter $seconds
		518
		519	Like C<again>, but also returns an increasing counter value, starting at
		520	0, which might be useful for some simple animation effects.
		521
		522	=cut
71		523
72	sub now() { urxvt::NOW }	524	sub now() { urxvt::NOW }
73		525
74	sub again($) {	526	sub again($) {
75	$new->{again} = $_[0];	527	$frame->[FR_AGAIN]{time} = $_[0];
76	}	528	}
77		529
78	sub counter($) {	530	sub counter($) {
79	$new->{again} = $_[0];	531	$frame->[FR_AGAIN]{time} = $_[0];
80	$bgdsl_self->{counter} + 0	532	$frame->[FR_STATE]{counter} + 0
81	}	533	}
82		534
83	=back	535	=back
84		536
85	=head2 OPERATORS	537	=head2 SHAPE CHANGING OPERATORS
		538
		539	The following operators modify the shape, size or position of the image.
86		540
87	=over 4	541	=over 4
88		542
89	=cut	543	=item clip $img
90		544
91	# sub clone($) {	545	=item clip $width, $height, $img
92	# $_[0]->clone	546
93	# }	547	=item clip $x, $y, $width, $height, $img
		548
		549	Clips an image to the given rectangle. If the rectangle is outside the
		550	image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is
		551	larger than the image, then the tiling mode defines how the extra pixels
		552	will be filled.
		553
		554	If C<$x> an C<$y> are missing, then C<0> is assumed for both.
		555
		556	If C<$width> and C<$height> are missing, then the window size will be
		557	assumed.
		558
		559	Example: load an image, blur it, and clip it to the window size to save
		560	memory.
		561
		562	clip blur 10, load "mybg.png"
		563
		564	=cut
94		565
95	sub clip($;$$;$$) {	566	sub clip($;$$;$$) {
96	my $img = pop;	567	my $img = pop;
97	my $h = pop \|\| H;	568	my $h = pop \|\| TH;
98	my $w = pop \|\| W;	569	my $w = pop \|\| TW;
99	$img->sub_rect ($_[0], $_[1], $w, $h)	570	$img->sub_rect ($_[0], $_[1], $w, $h)
		571	}
		572
		573	=item scale $img
		574
		575	=item scale $size_factor, $img
		576
		577	=item scale $width_factor, $height_factor, $img
		578
		579	Scales the image by the given factors in horizontal
		580	(C<$width>) and vertical (C<$height>) direction.
		581
		582	If only one factor is give, it is used for both directions.
		583
		584	If no factors are given, scales the image to the window size without
		585	keeping aspect.
		586
		587	=item resize $width, $height, $img
		588
		589	Resizes the image to exactly C<$width> times C<$height> pixels.
		590
		591	=item fit $img
		592
		593	=item fit $width, $height, $img
		594
		595	Fits the image into the given C<$width> and C<$height> without changing
		596	aspect, or the terminal size. That means it will be shrunk or grown until
		597	the whole image fits into the given area, possibly leaving borders.
		598
		599	=item cover $img
		600
		601	=item cover $width, $height, $img
		602
		603	Similar to C<fit>, but shrinks or grows until all of the area is covered
		604	by the image, so instead of potentially leaving borders, it will cut off
		605	image data that doesn't fit.
		606
		607	=cut
		608
		609	sub scale($;$;$) {
		610	my $img = pop;
		611
		612	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
		613	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
		614	: $img->scale (TW, TH)
100	}	615	}
101		616
102	sub resize($$$) {	617	sub resize($$$) {
103	my $img = pop;	618	my $img = pop;
104	$img->scale ($_[0], $_[1])	619	$img->scale ($_[0], $_[1])
105	}	620	}
106		621
107	# TODO: ugly	622	sub fit($;$$) {
		623	my $img = pop;
		624	my $w = ($_[0] \|\| TW) / $img->w;
		625	my $h = ($_[1] \|\| TH) / $img->h;
		626	scale +(min $w, $h), $img
		627	}
		628
		629	sub cover($;$$) {
		630	my $img = pop;
		631	my $w = ($_[0] \|\| TW) / $img->w;
		632	my $h = ($_[1] \|\| TH) / $img->h;
		633	scale +(max $w, $h), $img
		634	}
		635
		636	=item move $dx, $dy, $img
		637
		638	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
		639	the vertical.
		640
		641	Example: move the image right by 20 pixels and down by 30.
		642
		643	move 20, 30, ...
		644
		645	=item align $xalign, $yalign, $img
		646
		647	Aligns the image according to a factor - C<0> means the image is moved to
		648	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		649	exactly centered and C<1> means it touches the right or bottom edge.
		650
		651	Example: remove any visible border around an image, center it vertically but move
		652	it to the right hand side.
		653
		654	align 1, 0.5, pad $img
		655
		656	=item center $img
		657
		658	=item center $width, $height, $img
		659
		660	Centers the image, i.e. the center of the image is moved to the center of
		661	the terminal window (or the box specified by C<$width> and C<$height> if
		662	given).
		663
		664	Example: load an image and center it.
		665
		666	center pad load "mybg.png"
		667
		668	=item rootalign $img
		669
		670	Moves the image so that it appears glued to the screen as opposed to the
		671	window. This gives the illusion of a larger area behind the window. It is
		672	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
		673	top left of the screen.
		674
		675	Example: load a background image, put it in mirror mode and root align it.
		676
		677	rootalign mirror load "mybg.png"
		678
		679	Example: take the screen background and align it, giving the illusion of
		680	transparency as long as the window isn't in front of other windows.
		681
		682	rootalign root
		683
		684	=cut
		685
108	sub move($$;$) {	686	sub move($$;$) {
109	my $img = pop->clone;	687	my $img = pop->clone;
110	$img->move ($_[0], $_[1]);	688	$img->move ($_[0], $_[1]);
111	$img	689	$img
		690	}
		691
		692	sub align($;$$) {
112	# my $img = pop;	693	my $img = pop;
113	# $img->sub_rect (
114	# $_[0], $_[1],
115	# $img->w, $img->h,
116	# $_[2],
117	# )
118	}
119		694
		695	move $_[0] * (TW - $img->w),
		696	$_[1] * (TH - $img->h),
		697	$img
		698	}
		699
		700	sub center($;$$) {
		701	my $img = pop;
		702	my $w = $_[0] \|\| TW;
		703	my $h = $_[1] \|\| TH;
		704
		705	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		706	}
		707
		708	sub rootalign($) {
		709	move -TX, -TY, $_[0]
		710	}
		711
		712	=item rotate $center_x, $center_y, $degrees
		713
		714	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
		715	pointer at C<$center_x> and C<$center_y> (specified as factor of image
		716	width/height).
		717
		718	#TODO# new width, height, maybe more operators?
		719
		720	Example: rotate the image by 90 degrees
		721
		722	=cut
		723
120	sub rotate($$$$$$) {	724	sub rotate($$$$) {
121	my $img = pop;	725	my $img = pop;
122	$img->rotate (	726	$img->rotate (
123	$_[0],	727	$_[0] * ($img->w + $img->x),
124	$_[1],	728	$_[1] * ($img->h + $img->y),
125	$_[2] * $img->w * .01,
126	$_[3] * $img->h * .01,
127	$_[4] * (3.14159265 / 180),	729	$_[2] * (3.14159265 / 180),
128	)	730	)
129	}	731	}
130		732
131	sub blur($$$) {	733	=back
132	my ($rh, $rv, $img) = @_;
133		734
134	$img->blur ($rh, $rv);	735	=head2 COLOUR MODIFICATIONS
135	}	736
		737	The following operators change the pixels of the image.
		738
		739	=over 4
		740
		741	=item contrast $factor, $img
		742
		743	=item contrast $r, $g, $b, $img
		744
		745	=item contrast $r, $g, $b, $a, $img
		746
		747	Adjusts the I<contrast> of an image.
		748
		749	The first form applies a single C<$factor> to red, green and blue, the
		750	second form applies separate factors to each colour channel, and the last
		751	form includes the alpha channel.
		752
		753	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		754	contrast.
		755
		756	Due to limitations in the underlying XRender extension, lowering contrast
		757	also reduces brightness, while increasing contrast currently also
		758	increases brightness.
		759
		760	=item brightness $bias, $img
		761
		762	=item brightness $r, $g, $b, $img
		763
		764	=item brightness $r, $g, $b, $a, $img
		765
		766	Adjusts the brightness of an image.
		767
		768	The first form applies a single C<$bias> to red, green and blue, the
		769	second form applies separate biases to each colour channel, and the last
		770	form includes the alpha channel.
		771
		772	Values less than 0 reduce brightness, while values larger than 0 increase
		773	it. Useful range is from -1 to 1 - the former results in a black, the
		774	latter in a white picture.
		775
		776	Due to idiosyncrasies in the underlying XRender extension, biases less
		777	than zero can be I<very> slow.
		778
		779	=cut
136		780
137	sub contrast($$;$$;$) {	781	sub contrast($$;$$;$) {
138	my $img = pop;	782	my $img = pop;
139	my ($r, $g, $b, $a) = @_;	783	my ($r, $g, $b, $a) = @_;
140		784
141	($g, $b) = ($r, $r) if @_ < 4;	785	($g, $b) = ($r, $r) if @_ < 3;
142	$a = 1 if @_ < 5;	786	$a = 1 if @_ < 4;
143		787
144	$img = $img->clone;	788	$img = $img->clone;
145	$img->contrast ($r, $g, $b, $a);	789	$img->contrast ($r, $g, $b, $a);
146	$img	790	$img
147	}	791	}
148		792
149	sub brightness($$;$$;$) {	793	sub brightness($$;$$;$) {
150	my $img = pop;	794	my $img = pop;
151	my ($r, $g, $b, $a) = @_;	795	my ($r, $g, $b, $a) = @_;
152		796
153	($g, $b) = ($r, $r) if @_ < 4;	797	($g, $b) = ($r, $r) if @_ < 3;
154	$a = 1 if @_ < 5;	798	$a = 1 if @_ < 4;
155		799
156	$img = $img->clone;	800	$img = $img->clone;
157	$img->brightness ($r, $g, $b, $a);	801	$img->brightness ($r, $g, $b, $a);
158	$img	802	$img
159	}	803	}
160		804
		805	=item blur $radius, $img
		806
		807	=item blur $radius_horz, $radius_vert, $img
		808
		809	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
		810	can also be specified separately.
		811
		812	Blurring is often I<very> slow, at least compared or other
		813	operators. Larger blur radii are slower than smaller ones, too, so if you
		814	don't want to freeze your screen for long times, start experimenting with
		815	low values for radius (<5).
		816
		817	=cut
		818
		819	sub blur($$;$) {
		820	my $img = pop;
		821	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
		822	}
		823
161	=back	824	=back
162		825
		826	=head2 OTHER STUFF
		827
		828	Anything that didn't fit any of the other categories, even after applying
		829	force and closing our eyes.
		830
		831	=over 4
		832
		833	=item once { ... }
		834
		835	This function takes a code block as argument, that is, one or more
		836	statements enclosed by braces.
		837
		838	The trick is that this code block is only evaluated once - future calls
		839	will simply return the original image (yes, it should only be used with
		840	images).
		841
		842	This can be extremely useful to avoid redoing the same slow operations
		843	again and again- for example, if your background expression takes the root
		844	background, blurs it and then root-aligns it it would have to blur the
		845	root background on every window move or resize.
		846
		847	In fact, urxvt itself encloses the whole expression in some kind of
		848	C<once> block so it only is reevaluated as required.
		849
		850	Putting the blur into a C<once> block will make sure the blur is only done
		851	once:
		852
		853	rootlign once { blur 10, root }
		854
		855	This leaves the question of how to force reevaluation of the block,
		856	in case the root background changes: If expression inside the block
		857	is sensitive to some event (root background changes, window geometry
		858	changes), then it will be reevaluated automatically as needed.
		859
		860	=item once_again
		861
		862	Resets all C<once> block as if they had never been called, i.e. on the
		863	next call they will be reevaluated again.
		864
		865	=cut
		866
		867	sub once(&) {
		868	my $id = $_[0]+0;
		869
		870	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		871
		872	unless ($frame->[FR_CACHE]) {
		873	$frame->[FR_CACHE] = [ $_[0]() ];
		874
		875	my $self = $self;
		876	my $frame = $frame;
		877	Scalar::Util::weaken $frame;
		878	$self->compile_frame ($frame, sub {
		879	# clear this frame cache, also for all parents
		880	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		881	undef $frame->[FR_CACHE];
		882	}
		883
		884	unless ($self->{term}) {
		885	use Data::Dump;
		886	ddx $frame;
		887	exit;
		888	}
		889
		890	$self->recalculate;
		891	});
		892	};
		893
		894	# in scalar context we always return the first original result, which
		895	# is not quite how perl works.
		896	wantarray
		897	? @{ $frame->[FR_CACHE] }
		898	: $frame->[FR_CACHE][0]
		899	}
		900
		901	sub once_again() {
		902	delete $self->{frame_cache};
		903	}
		904
		905	=back
		906
163	=cut	907	=cut
164		908
165	}	909	}
166		910
167	sub parse_expr {	911	sub parse_expr {
168	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	912	my $expr = eval
		913	"sub {\n"
		914	. "package urxvt::bgdsl;\n"
		915	. "#line 0 'background expression'\n"
		916	. "$_[0]\n"
		917	. "}";
169	die if $@;	918	die if $@;
170	$expr	919	$expr
171	}	920	}
172		921
173	# compiles a parsed expression	922	# compiles a parsed expression
174	sub set_expr {	923	sub set_expr {
175	my ($self, $expr) = @_;	924	my ($self, $expr) = @_;
176		925
		926	$self->{root} = [];
177	$self->{expr} = $expr;	927	$self->{expr} = $expr;
178	$self->recalculate;	928	$self->recalculate;
179	}	929	}
180		930
		931	# takes a hash of sensitivity indicators and installs watchers
		932	sub compile_frame {
		933	my ($self, $frame, $cb) = @_;
		934
		935	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		936	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		937
		938	# don't keep stuff alive
		939	Scalar::Util::weaken $state;
		940
		941	if ($again->{nested}) {
		942	$state->{nested} = 1;
		943	} else {
		944	delete $state->{nested};
		945	}
		946
		947	if (my $interval = $again->{time}) {
		948	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		949	if $state->{time}[0] != $interval;
		950
		951	# callback might have changed, although we could just rule that out
		952	$state->{time}[1]->cb (sub {
		953	++$state->{counter};
		954	$cb->();
		955	});
		956	} else {
		957	delete $state->{time};
		958	}
		959
		960	if ($again->{position}) {
		961	$state->{position} = $self->on (position_change => $cb);
		962	} else {
		963	delete $state->{position};
		964	}
		965
		966	if ($again->{size}) {
		967	$state->{size} = $self->on (size_change => $cb);
		968	} else {
		969	delete $state->{size};
		970	}
		971
		972	if ($again->{rootpmap}) {
		973	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		974	} else {
		975	delete $state->{rootpmap};
		976	}
		977	}
		978
181	# evaluate the current bg expression	979	# evaluate the current bg expression
182	sub recalculate {	980	sub recalculate {
183	my ($self) = @_;	981	my ($arg_self) = @_;
184		982
185	# rate limit evaluation	983	# rate limit evaluation
186		984
187	if ($self->{next_refresh} > urxvt::NOW) {	985	if ($arg_self->{next_refresh} > urxvt::NOW) {
188	$self->{next_refresh_timer} = urxvt::timer->new->after ($self->{next_refresh} - urxvt::NOW)->cb (sub {	986	$arg_self->{next_refresh_timer} = urxvt::timer->new->after ($arg_self->{next_refresh} - urxvt::NOW)->cb (sub {
189	$self->recalculate;	987	$arg_self->recalculate;
190	});	988	});
191	return;	989	return;
192	}	990	}
193		991
194	$self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	992	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
195		993
196	# set environment to evaluate user expression	994	# set environment to evaluate user expression
197		995
198	local $bgdsl_self = $self;	996	local $self = $arg_self;
		997	local $HOME = $ENV{HOME};
		998	local $frame = [];
199		999
200	local $old = $self->{state};	1000	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
201	local $new = my $state = $self->{state} = {};
202
203	($l, $t, $w, $h) =
204	$self->get_geometry;
205
206	warn "$l,$t,$w,$h\n";#d#
207		1001
208	# evaluate user expression	1002	# evaluate user expression
209		1003
210	my $img = eval { $self->{expr}->() };	1004	my @img = eval { $self->{expr}->() };
211	warn $@ if $@;#d#	1005	die $@ if $@;
		1006	die "background-expr did not return anything.\n" unless @img;
		1007	die "background-expr: expected image(s), got something else.\n"
212	die if !UNIVERSAL::isa $img, "urxvt::img";	1008	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
		1009
		1010	my $img = urxvt::bgdsl::merge @img;
		1011
		1012	$frame->[FR_AGAIN]{size} = 1
		1013	if $img->repeat_mode != urxvt::RepeatNormal;
213		1014
214	# if the expression is sensitive to external events, prepare reevaluation then	1015	# if the expression is sensitive to external events, prepare reevaluation then
215		1016	$self->compile_frame ($frame, sub { $arg_self->recalculate });
216	my $repeat;
217
218	if (my $again = $state->{again}) {
219	$repeat = 1;
220	$state->{timer} = $again == $old->{again}
221	? $old->{timer}
222	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
223	++$self->{counter};
224	$self->recalculate
225	});
226	}
227
228	if (delete $state->{position_sensitive}) {
229	$repeat = 1;
230	$self->enable (position_change => sub { $_[0]->recalculate });
231	} else {
232	$self->disable ("position_change");
233	}
234
235	if (delete $state->{size_sensitive}) {
236	$repeat = 1;
237	$self->enable (size_change => sub { $_[0]->recalculate });
238	} else {
239	$self->disable ("size_change");
240	}
241
242	if (delete $state->{rootpmap_sensitive}) {
243	$repeat = 1;
244	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
245	} else {
246	$self->disable ("rootpmap_change");
247	}
248		1017
249	# clear stuff we no longer need	1018	# clear stuff we no longer need
250		1019
251	%$old = ();	1020	# unless (%{ $frame->[FR_STATE] }) {
252
253	unless ($repeat) {
254	delete $self->{state};	1021	# delete $self->{state};
255	delete $self->{expr};	1022	# delete $self->{expr};
256	}	1023	# }
257		1024
258	# prepare and set background pixmap	1025	# set background pixmap
259		1026
260	$img = $img->sub_rect (0, 0, $w, $h)
261	if $img->w != $w \|\| $img->h != $h;
262
263	$self->set_background ($img);	1027	$self->set_background ($img, $self->{border});
264	$self->scr_recolour (0);	1028	$self->scr_recolour (0);
265	$self->want_refresh;	1029	$self->want_refresh;
266	}	1030	}
267		1031
268	sub on_start {	1032	sub on_start {
269	my ($self) = @_;	1033	my ($self) = @_;
270		1034
		1035	my $expr = $self->x_resource ("%.expr")
		1036	or return;
		1037
		1038	$self->has_render
		1039	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1040
271	$self->set_expr (parse_expr $EXPR);	1041	$self->set_expr (parse_expr $expr);
		1042	$self->{border} = $self->x_resource_boolean ("%.border");
		1043
		1044	$MIN_INTERVAL = $self->x_resource ("%.interval");
272		1045
273	()	1046	()
274	}	1047	}
275		1048

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.23 by root, Thu Jun 7 10:22:55 2012 UTC vs. Revision 1.63 by root, Tue Jun 19 18:17:56 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.23 by root, Thu Jun 7 10:22:55 2012 UTC vs.
Revision 1.63 by root, Tue Jun 19 18:17:56 2012 UTC