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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.1 by root, Mon Jun 4 21:39:56 2012 UTC vs.
Revision 1.74 by root, Sat Jul 14 08:42:54 2012 UTC

1	#! perl	1	#! perl
2		2
3	our $EXPR = 'resize (blur (load "/root/pix/das_fette_schwein.jpg", 1 + (counter 1) % 10, 10), w, h)';	3	#:META:X_RESOURCE:%.expr:string:background expression
4	#$EXPR = 'blur root, 10, 10'	4	#:META:X_RESOURCE:%.border:boolean:respect the terminal border
5	#$EXPR = 'blur move (root, -x, -y), 5, 5'	5	#:META:X_RESOURCE:%.interval:seconds:minimum time between updates
6	#resize load "/root/pix/das_fette_schwein.jpg", w, h
7		6
8	use Safe;	7	=head1 NAME
		8
		9	background - manage terminal background
		10
		11	=head1 SYNOPSIS
		12
		13	urxvt --background-expr 'background expression'
		14	--background-border
		15	--background-interval seconds
		16
		17	=head1 DESCRIPTION
		18
		19	This extension manages the terminal background by creating a picture that
		20	is behind the text, replacing the normal background colour.
		21
		22	It does so by evaluating a Perl expression that I<calculates> the image on
		23	the fly, for example, by grabbing the root background or loading a file.
		24
		25	While the full power of Perl is available, the operators have been design
		26	to be as simple as possible.
		27
		28	For example, to load an image and scale it to the window size, you would
		29	use:
		30
		31	urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
		32
		33	Or specified as a X resource:
		34
		35	URxvt.background-expr: scale keep { load "/path/to/mybg.png" }
		36
		37	=head1 THEORY OF OPERATION
		38
		39	At startup, just before the window is mapped for the first time, the
		40	expression is evaluated and must yield an image. The image is then
		41	extended as necessary to cover the whole terminal window, and is set as a
		42	background pixmap.
		43
		44	If the image contains an alpha channel, then it will be used as-is in
		45	visuals that support alpha channels (for example, for a compositing
		46	manager). In other visuals, the terminal background colour will be used to
		47	replace any transparency.
		48
		49	When the expression relies, directly or indirectly, on the window size,
		50	position, the root pixmap, or a timer, then it will be remembered. If not,
		51	then it will be removed.
		52
		53	If any of the parameters that the expression relies on changes (when the
		54	window is moved or resized, its position or size changes; when the root
		55	pixmap is replaced by another one the root background changes; or when the
		56	timer elapses), then the expression will be evaluated again.
		57
		58	For example, an expression such as C<scale keep { load "$HOME/mybg.png"
		59	}> scales the image to the window size, so it relies on the window size
		60	and will be reevaluated each time it is changed, but not when it moves for
		61	example. That ensures that the picture always fills the terminal, even
		62	after its size changes.
		63
		64	=head2 EXPRESSIONS
		65
		66	Expressions are normal Perl expressions, in fact, they are Perl blocks -
		67	which means you could use multiple lines and statements:
		68
		69	scale keep {
		70	again 3600;
		71	if (localtime now)[6]) {
		72	return load "$HOME/weekday.png";
		73	} else {
		74	return load "$HOME/sunday.png";
		75	}
		76	}
		77
		78	This inner expression is evaluated once per hour (and whenever the
		79	terminal 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 "$HOME/mypic.png"
		122
		123	IF you try out these expressions, you might suffer from some sluggishness,
		124	because each time the terminal is resized, it loads the PNG image again
		125	and scales it. Scaling is usually fast (and unavoidable), but loading the
		126	image can be quite time consuming. This is where C<keep> comes in handy:
		127
		128	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		129
		130	The C<keep> operator executes all the statements inside the braces only
		131	once, or when it thinks the outcome might change. In other cases it
		132	returns the last value computed by the brace block.
		133
		134	This means that the C<load> is only executed once, which makes it much
		135	faster, but also means that more memory is being used, because the loaded
		136	image must be kept in memory at all times. In this expression, the
		137	trade-off is likely worth it.
		138
		139	But back to effects: Other effects than scaling are also readily
		140	available, for example, you can tile the image to fill the whole window,
		141	instead of resizing it:
		142
		143	tile keep { load "$HOME/mypic.png" }
		144
		145	In fact, images returned by C<load> are in C<tile> mode by default, so the
		146	C<tile> operator is kind of superfluous.
		147
		148	Another common effect is to mirror the image, so that the same edges
		149	touch:
		150
		151	mirror keep { load "$HOME/mypic.png" }
		152
		153	Another common background expression is:
		154
		155	rootalign root
		156
		157	This one first takes a snapshot of the screen background image, and then
		158	moves it to the upper left corner of the screen (as opposed to the upper
		159	left corner of the terminal window)- the result is pseudo-transparency:
		160	the image seems to be static while the window is moved around.
		161
		162	=head2 COLOUR SPECIFICATIONS
		163
		164	Whenever an operator expects a "colour", then this can be specified in one
		165	of two ways: Either as string with an X11 colour specification, such as:
		166
		167	"red" # named colour
		168	"#f00" # simple rgb
		169	"[50]red" # red with 50% alpha
		170	"TekHVC:300/50/50" # anything goes
		171
		172	OR as an array reference with one, three or four components:
		173
		174	[0.5] # 50% gray, 100% alpha
		175	[0.5, 0, 0] # dark red, no green or blur, 100% alpha
		176	[0.5, 0, 0, 0.7] # same with explicit 70% alpha
		177
		178	=head2 CACHING AND SENSITIVITY
		179
		180	Since some operations (such as C<load> and C<blur>) can take a long time,
		181	caching results can be very important for a smooth operation. Caching can
		182	also be useful to reduce memory usage, though, for example, when an image
		183	is cached by C<load>, it could be shared by multiple terminal windows
		184	running inside urxvtd.
		185
		186	=head3 C<keep { ... }> caching
		187
		188	The most important way to cache expensive operations is to use C<keep {
		189	... }>. The C<keep> operator takes a block of multiple statements enclosed
		190	by C<{}> and keeps the return value in memory.
		191
		192	An expression can be "sensitive" to various external events, such as
		193	scaling or moving the window, root background changes and timers. Simply
		194	using an expression (such as C<scale> without parameters) that depends on
		195	certain changing values (called "variables"), or using those variables
		196	directly, will make an expression sensitive to these events - for example,
		197	using C<scale> or C<TW> will make the expression sensitive to the terminal
		198	size, and thus to resizing events.
		199
		200	When such an event happens, C<keep> will automatically trigger a
		201	reevaluation of the whole expression with the new value of the expression.
		202
		203	C<keep> is most useful for expensive operations, such as C<blur>:
		204
		205	rootalign keep { blur 20, root }
		206
		207	This makes a blurred copy of the root background once, and on subsequent
		208	calls, just root-aligns it. Since C<blur> is usually quite slow and
		209	C<rootalign> is quite fast, this trades extra memory (for the cached
		210	blurred pixmap) with speed (blur only needs to be redone when root
		211	changes).
		212
		213	=head3 C<load> caching
		214
		215	The C<load> operator itself does not keep images in memory, but as long as
		216	the image is still in memory, C<load> will use the in-memory image instead
		217	of loading it freshly from disk.
		218
		219	That means that this expression:
		220
		221	keep { load "$HOME/path..." }
		222
		223	Not only caches the image in memory, other terminal instances that try to
		224	C<load> it can reuse that in-memory copy.
		225
		226	=head1 REFERENCE
		227
		228	=head2 COMMAND LINE SWITCHES
		229
		230	=over 4
		231
		232	=item --background-expr perl-expression
		233
		234	Specifies the Perl expression to evaluate.
		235
		236	=item --background-border
		237
		238	By default, the expression creates an image that fills the full window,
		239	overwriting borders and any other areas, such as the scrollbar.
		240
		241	Specifying this flag changes the behaviour, so that the image only
		242	replaces the background of the character area.
		243
		244	=item --background-interval seconds
		245
		246	Since some operations in the underlying XRender extension can effectively
		247	freeze your X-server for prolonged time, this extension enforces a minimum
		248	time between updates, which is normally about 0.1 seconds.
		249
		250	If you want to do updates more often, you can decrease this safety
		251	interval with this switch.
		252
		253	=back
		254
		255	=cut
		256
		257	our %_IMG_CACHE;
		258	our $HOME;
		259	our ($self, $frame);
		260	our ($x, $y, $w, $h);
		261
		262	# enforce at least this interval between updates
		263	our $MIN_INTERVAL = 6/59.951;
9		264
10	{	265	{
11	package urxvt::bgdsl::vars;
12
13	our ($self, $old, $new);
14	our ($x, $y, $w, $h);
15
16	package urxvt::bgdsl; # background language	266	package urxvt::bgdsl; # background language
17		267
18	*repeat_black = \&urxvt::RepeatNone; #TODO wtf	268	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
19	*repeat_wrap = \&urxvt::RepeatNormal;	269	sub FR_CACHE () { 1 } # cached values
20	*repeat_pad = \&urxvt::RepeatPad;	270	sub FR_AGAIN () { 2 } # what this expr is sensitive to
21	*repeat_mirror = \&urxvt::RepeatReflect;	271	sub FR_STATE () { 3 } # watchers etc.
22		272
		273	use List::Util qw(min max sum shuffle);
		274
		275	=head2 PROVIDERS/GENERATORS
		276
		277	These functions provide an image, by loading it from disk, grabbing it
		278	from the root screen or by simply generating it. They are used as starting
		279	points to get an image you can play with.
		280
		281	=over 4
		282
		283	=item load $path
		284
		285	Loads the image at the given C<$path>. The image is set to plane tiling
		286	mode.
		287
		288	If the image is already in memory (e.g. because another terminal instance
		289	uses it), then the in-memory copy us returned instead.
		290
		291	=item load_uc $path
		292
		293	Load uncached - same as load, but does not cache the image, which means it
		294	is I<always> loaded from the filesystem again, even if another copy of it
		295	is in memory at the time.
		296
		297	=cut
		298
		299	sub load_uc($) {
		300	$self->new_img_from_file ($_[0])
		301	}
		302
23	sub load {	303	sub load($) {
24	my ($path) = @_;	304	my ($path) = @_;
25		305
26	$new->{load}{$path} = $old->{load}{$path} \|\| $self->new_img_from_file ($path);	306	$_IMG_CACHE{$path} \|\| do {
		307	my $img = load_uc $path;
		308	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		309	$img
		310	}
27	}	311	}
28		312
		313	=item root
		314
		315	Returns the root window pixmap, that is, hopefully, the background image
		316	of your screen.
		317
		318	This function makes your expression root sensitive, that means it will be
		319	reevaluated when the bg image changes.
		320
		321	=cut
		322
29	sub root {	323	sub root() {
30	die "root op not supported, exg, we need you";	324	$frame->[FR_AGAIN]{rootpmap} = 1;
		325	$self->new_img_from_root
31	}	326	}
32		327
		328	=item solid $colour
		329
		330	=item solid $width, $height, $colour
		331
		332	Creates a new image and completely fills it with the given colour. The
		333	image is set to tiling mode.
		334
		335	If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
		336	useful for solid backgrounds or for use in filtering effects.
		337
		338	=cut
		339
		340	sub solid($;$$) {
		341	my $colour = pop;
		342
		343	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
		344	$img->fill ($colour);
		345	$img
		346	}
		347
		348	=item clone $img
		349
		350	Returns an exact copy of the image. This is useful if you want to have
		351	multiple copies of the same image to apply different effects to.
		352
		353	=cut
		354
		355	sub clone($) {
		356	$_[0]->clone
		357	}
		358
		359	=item merge $img ...
		360
		361	Takes any number of images and merges them together, creating a single
		362	image containing them all. The tiling mode of the first image is used as
		363	the tiling mode of the resulting image.
		364
		365	This function is called automatically when an expression returns multiple
		366	images.
		367
		368	=cut
		369
		370	sub merge(@) {
		371	return $_[0] unless $#_;
		372
		373	# rather annoyingly clumsy, but optimisation is for another time
		374
		375	my $x0 = +1e9;
		376	my $y0 = +1e9;
		377	my $x1 = -1e9;
		378	my $y1 = -1e9;
		379
		380	for (@_) {
		381	my ($x, $y, $w, $h) = $_->geometry;
		382
		383	$x0 = $x if $x0 > $x;
		384	$y0 = $y if $y0 > $y;
		385
		386	$x += $w;
		387	$y += $h;
		388
		389	$x1 = $x if $x1 < $x;
		390	$y1 = $y if $y1 < $y;
		391	}
		392
		393	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		394	$base->repeat_mode ($_[0]->repeat_mode);
		395	$base->fill ([0, 0, 0, 0]);
		396
		397	$base->draw ($_)
		398	for @_;
		399
		400	$base
		401	}
		402
		403	=head2 TILING MODES
		404
		405	The following operators modify the tiling mode of an image, that is, the
		406	way that pixels outside the image area are painted when the image is used.
		407
		408	=over 4
		409
		410	=item tile $img
		411
		412	Tiles the whole plane with the image and returns this new image - or in
		413	other words, it returns a copy of the image in plane tiling mode.
		414
		415	Example: load an image and tile it over the background, without
		416	resizing. The C<tile> call is superfluous because C<load> already defaults
		417	to tiling mode.
		418
		419	tile load "mybg.png"
		420
		421	=item mirror $img
		422
		423	Similar to tile, but reflects the image each time it uses a new copy, so
		424	that top edges always touch top edges, right edges always touch right
		425	edges and so on (with normal tiling, left edges always touch right edges
		426	and top always touch bottom edges).
		427
		428	Example: load an image and mirror it over the background, avoiding sharp
		429	edges at the image borders at the expense of mirroring the image itself
		430
		431	mirror load "mybg.png"
		432
		433	=item pad $img
		434
		435	Takes an image and modifies it so that all pixels outside the image area
		436	become transparent. This mode is most useful when you want to place an
		437	image over another image or the background colour while leaving all
		438	background pixels outside the image unchanged.
		439
		440	Example: load an image and display it in the upper left corner. The rest
		441	of the space is left "empty" (transparent or whatever your compositor does
		442	in alpha mode, else background colour).
		443
		444	pad load "mybg.png"
		445
		446	=item extend $img
		447
		448	Extends the image over the whole plane, using the closest pixel in the
		449	area outside the image. This mode is mostly useful when you use more complex
		450	filtering operations and want the pixels outside the image to have the
		451	same values as the pixels near the edge.
		452
		453	Example: just for curiosity, how does this pixel extension stuff work?
		454
		455	extend move 50, 50, load "mybg.png"
		456
		457	=cut
		458
		459	sub pad($) {
		460	my $img = $_[0]->clone;
		461	$img->repeat_mode (urxvt::RepeatNone);
		462	$img
		463	}
		464
		465	sub tile($) {
		466	my $img = $_[0]->clone;
		467	$img->repeat_mode (urxvt::RepeatNormal);
		468	$img
		469	}
		470
		471	sub mirror($) {
		472	my $img = $_[0]->clone;
		473	$img->repeat_mode (urxvt::RepeatReflect);
		474	$img
		475	}
		476
		477	sub extend($) {
		478	my $img = $_[0]->clone;
		479	$img->repeat_mode (urxvt::RepeatPad);
		480	$img
		481	}
		482
		483	=back
		484
		485	=head2 VARIABLE VALUES
		486
		487	The following functions provide variable data such as the terminal window
		488	dimensions. They are not (Perl-) variables, they just return stuff that
		489	varies. Most of them make your expression sensitive to some events, for
		490	example using C<TW> (terminal width) means your expression is evaluated
		491	again when the terminal is resized.
		492
		493	=over 4
		494
		495	=item TX
		496
		497	=item TY
		498
		499	Return the X and Y coordinates of the terminal window (the terminal
		500	window is the full window by default, and the character area only when in
		501	border-respect mode).
		502
		503	Using these functions make your expression sensitive to window moves.
		504
		505	These functions are mainly useful to align images to the root window.
		506
		507	Example: load an image and align it so it looks as if anchored to the
		508	background (that's exactly what C<rootalign> does btw.):
		509
		510	move -TX, -TY, keep { load "mybg.png" }
		511
		512	=item TW
		513
		514	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		515	terminal window is the full window by default, and the character area only
		516	when in border-respect mode).
		517
		518	Using these functions make your expression sensitive to window resizes.
		519
		520	These functions are mainly useful to scale images, or to clip images to
		521	the window size to conserve memory.
		522
		523	Example: take the screen background, clip it to the window size, blur it a
		524	bit, align it to the window position and use it as background.
		525
		526	clip move -TX, -TY, keep { blur 5, root }
		527
		528	=cut
		529
		530	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
		531	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
		532	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
		533	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
		534
		535	=item now
		536
		537	Returns the current time as (fractional) seconds since the epoch.
		538
		539	Using this expression does I<not> make your expression sensitive to time,
		540	but the next two functions do.
		541
		542	=item again $seconds
		543
		544	When this function is used the expression will be reevaluated again in
		545	C<$seconds> seconds.
		546
		547	Example: load some image and rotate it according to the time of day (as if it were
		548	the hour pointer of a clock). Update this image every minute.
		549
		550	again 60;
		551	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
		552
		553	=item counter $seconds
		554
		555	Like C<again>, but also returns an increasing counter value, starting at
		556	0, which might be useful for some simple animation effects.
		557
		558	=cut
		559
		560	sub now() { urxvt::NOW }
		561
		562	sub again($) {
		563	$frame->[FR_AGAIN]{time} = $_[0];
		564	}
		565
		566	sub counter($) {
		567	$frame->[FR_AGAIN]{time} = $_[0];
		568	$frame->[FR_STATE]{counter} + 0
		569	}
		570
		571	=back
		572
		573	=head2 SHAPE CHANGING OPERATORS
		574
		575	The following operators modify the shape, size or position of the image.
		576
		577	=over 4
		578
		579	=item clip $img
		580
		581	=item clip $width, $height, $img
		582
		583	=item clip $x, $y, $width, $height, $img
		584
		585	Clips an image to the given rectangle. If the rectangle is outside the
		586	image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is
		587	larger than the image, then the tiling mode defines how the extra pixels
		588	will be filled.
		589
		590	If C<$x> an C<$y> are missing, then C<0> is assumed for both.
		591
		592	If C<$width> and C<$height> are missing, then the window size will be
		593	assumed.
		594
		595	Example: load an image, blur it, and clip it to the window size to save
		596	memory.
		597
		598	clip keep { blur 10, load "mybg.png" }
		599
		600	=cut
		601
		602	sub clip($;$$;$$) {
		603	my $img = pop;
		604	my $h = pop \|\| TH;
		605	my $w = pop \|\| TW;
		606	$img->sub_rect ($_[0], $_[1], $w, $h)
		607	}
		608
		609	=item scale $img
		610
		611	=item scale $size_factor, $img
		612
		613	=item scale $width_factor, $height_factor, $img
		614
		615	Scales the image by the given factors in horizontal
		616	(C<$width>) and vertical (C<$height>) direction.
		617
		618	If only one factor is give, it is used for both directions.
		619
		620	If no factors are given, scales the image to the window size without
		621	keeping aspect.
		622
		623	=item resize $width, $height, $img
		624
		625	Resizes the image to exactly C<$width> times C<$height> pixels.
		626
		627	=item fit $img
		628
		629	=item fit $width, $height, $img
		630
		631	Fits the image into the given C<$width> and C<$height> without changing
		632	aspect, or the terminal size. That means it will be shrunk or grown until
		633	the whole image fits into the given area, possibly leaving borders.
		634
		635	=item cover $img
		636
		637	=item cover $width, $height, $img
		638
		639	Similar to C<fit>, but shrinks or grows until all of the area is covered
		640	by the image, so instead of potentially leaving borders, it will cut off
		641	image data that doesn't fit.
		642
		643	=cut
		644
		645	sub scale($;$;$) {
		646	my $img = pop;
		647
		648	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
		649	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
		650	: $img->scale (TW, TH)
		651	}
		652
33	sub resize {	653	sub resize($$$) {
34	$_[0]->scale ($_[1], $_[2])	654	my $img = pop;
		655	$img->scale ($_[0], $_[1])
35	}	656	}
36		657
		658	sub fit($;$$) {
		659	my $img = pop;
		660	my $w = ($_[0] \|\| TW) / $img->w;
		661	my $h = ($_[1] \|\| TH) / $img->h;
		662	scale +(min $w, $h), $img
		663	}
		664
		665	sub cover($;$$) {
		666	my $img = pop;
		667	my $w = ($_[0] \|\| TW) / $img->w;
		668	my $h = ($_[1] \|\| TH) / $img->h;
		669	scale +(max $w, $h), $img
		670	}
		671
		672	=item move $dx, $dy, $img
		673
		674	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
		675	the vertical.
		676
		677	Example: move the image right by 20 pixels and down by 30.
		678
		679	move 20, 30, ...
		680
		681	=item align $xalign, $yalign, $img
		682
		683	Aligns the image according to a factor - C<0> means the image is moved to
		684	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		685	exactly centered and C<1> means it touches the right or bottom edge.
		686
		687	Example: remove any visible border around an image, center it vertically but move
		688	it to the right hand side.
		689
		690	align 1, 0.5, pad $img
		691
		692	=item center $img
		693
		694	=item center $width, $height, $img
		695
		696	Centers the image, i.e. the center of the image is moved to the center of
		697	the terminal window (or the box specified by C<$width> and C<$height> if
		698	given).
		699
		700	Example: load an image and center it.
		701
		702	center keep { pad load "mybg.png" }
		703
		704	=item rootalign $img
		705
		706	Moves the image so that it appears glued to the screen as opposed to the
		707	window. This gives the illusion of a larger area behind the window. It is
		708	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
		709	top left of the screen.
		710
		711	Example: load a background image, put it in mirror mode and root align it.
		712
		713	rootalign keep { mirror load "mybg.png" }
		714
		715	Example: take the screen background and align it, giving the illusion of
		716	transparency as long as the window isn't in front of other windows.
		717
		718	rootalign root
		719
		720	=cut
		721
37	sub move {	722	sub move($$;$) {
38	# TODO: must be simpler	723	my $img = pop->clone;
39	$_[0]->transform ($_[0]->w, $_[0]->h, $_[1],	724	$img->move ($_[0], $_[1]);
40	1, 0, -$_[2],	725	$img
41	0, 1, -$_[3],	726	}
42	0, 0, 1,	727
		728	sub align($;$$) {
		729	my $img = pop;
		730
		731	move $_[0] * (TW - $img->w),
		732	$_[1] * (TH - $img->h),
		733	$img
		734	}
		735
		736	sub center($;$$) {
		737	my $img = pop;
		738	my $w = $_[0] \|\| TW;
		739	my $h = $_[1] \|\| TH;
		740
		741	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		742	}
		743
		744	sub rootalign($) {
		745	move -TX, -TY, $_[0]
		746	}
		747
		748	=item rotate $center_x, $center_y, $degrees, $img
		749
		750	Rotates the image clockwise by C<$degrees> degrees, around the point at
		751	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		752
		753	Example: rotate the image by 90 degrees around it's center.
		754
		755	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		756
		757	=cut
		758
		759	sub rotate($$$$) {
		760	my $img = pop;
		761	$img->rotate (
		762	$_[0] * ($img->w + $img->x),
		763	$_[1] * ($img->h + $img->y),
		764	$_[2] * (3.14159265 / 180),
43	)	765	)
44	}	766	}
45		767
46	sub rotate {	768	=back
47	$_[0]->rotate ($_[0], $_[1], $_[2], $_[3] * (3.14159265 / 180))
48	}
49		769
50	sub blur {	770	=head2 COLOUR MODIFICATIONS
51	my ($img, $rh, $rv) = @_;
52		771
53	$img = $img->clone;	772	The following operators change the pixels of the image.
54	$img->clone->blur ($rh, $rv);
55	$img
56	}
57		773
		774	=over 4
		775
		776	=item tint $color, $img
		777
		778	Tints the image in the given colour.
		779
		780	Example: tint the image red.
		781
		782	tint "red", load "rgb.png"
		783
		784	Example: the same, but specify the colour by component.
		785
		786	tint [1, 0, 0], load "rgb.png"
		787
		788	=cut
		789
		790	sub tint($$) {
		791	$_[1]->tint ($_[0])
		792	}
		793
		794	=item contrast $factor, $img
		795
		796	=item contrast $r, $g, $b, $img
		797
		798	=item contrast $r, $g, $b, $a, $img
		799
		800	Adjusts the I<contrast> of an image.
		801
		802	The first form applies a single C<$factor> to red, green and blue, the
		803	second form applies separate factors to each colour channel, and the last
		804	form includes the alpha channel.
		805
		806	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		807	contrast.
		808
		809	Due to limitations in the underlying XRender extension, lowering contrast
		810	also reduces brightness, while increasing contrast currently also
		811	increases brightness.
		812
		813	=item brightness $bias, $img
		814
		815	=item brightness $r, $g, $b, $img
		816
		817	=item brightness $r, $g, $b, $a, $img
		818
		819	Adjusts the brightness of an image.
		820
		821	The first form applies a single C<$bias> to red, green and blue, the
		822	second form applies separate biases to each colour channel, and the last
		823	form includes the alpha channel.
		824
		825	Values less than 0 reduce brightness, while values larger than 0 increase
		826	it. Useful range is from -1 to 1 - the former results in a black, the
		827	latter in a white picture.
		828
		829	Due to idiosyncrasies in the underlying XRender extension, biases less
		830	than zero can be I<very> slow.
		831
		832	=cut
		833
58	sub contrast {	834	sub contrast($$;$$;$) {
		835	my $img = pop;
59	my ($img, $r, $g, $b, $a) = @_;	836	my ($r, $g, $b, $a) = @_;
		837
60	($g, $b) = ($r, $r) if @_ < 4;	838	($g, $b) = ($r, $r) if @_ < 3;
61	$a = 1 if @_ < 5;	839	$a = 1 if @_ < 4;
		840
62	$img = $img->clone;	841	$img = $img->clone;
63	$img->contrast ($r, $g, $b, $a);	842	$img->contrast ($r, $g, $b, $a);
64	$img	843	$img
65	}	844	}
66		845
67	sub brightness {	846	sub brightness($$;$$;$) {
		847	my $img = pop;
68	my ($img, $r, $g, $b, $a) = @_;	848	my ($r, $g, $b, $a) = @_;
		849
69	($g, $b) = ($r, $r) if @_ < 4;	850	($g, $b) = ($r, $r) if @_ < 3;
70	$a = 1 if @_ < 5;	851	$a = 1 if @_ < 4;
		852
71	$img = $img->clone;	853	$img = $img->clone;
72	$img->brightness ($r, $g, $b, $a);	854	$img->brightness ($r, $g, $b, $a);
73	$img	855	$img
74	}	856	}
75		857
76	sub x { $new->{position_sensitive} = 1; $x }	858	=item blur $radius, $img
77	sub y { $new->{position_sensitive} = 1; $y }
78	sub w { $new->{size_sensitive} = 1; $w }
79	sub h { $new->{size_sensitive} = 1; $h }
80	sub now { urxvt::NOW }
81		859
82	sub again {	860	=item blur $radius_horz, $radius_vert, $img
83	$new->{again} = $_[0];	861
		862	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
		863	can also be specified separately.
		864
		865	Blurring is often I<very> slow, at least compared or other
		866	operators. Larger blur radii are slower than smaller ones, too, so if you
		867	don't want to freeze your screen for long times, start experimenting with
		868	low values for radius (<5).
		869
		870	=cut
		871
		872	sub blur($$;$) {
		873	my $img = pop;
		874	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
		875	}
		876
		877	=back
		878
		879	=head2 OTHER STUFF
		880
		881	Anything that didn't fit any of the other categories, even after applying
		882	force and closing our eyes.
		883
		884	=over 4
		885
		886	=item keep { ... }
		887
		888	This operator takes a code block as argument, that is, one or more
		889	statements enclosed by braces.
		890
		891	The trick is that this code block is only evaluated when the outcome
		892	changes - on other calls the C<keep> simply returns the image it computed
		893	previously (yes, it should only be used with images). Or in other words,
		894	C<keep> I<caches> the result of the code block so it doesn't need to be
		895	computed again.
		896
		897	This can be extremely useful to avoid redoing slow operations - for
		898	example, if your background expression takes the root background, blurs it
		899	and then root-aligns it it would have to blur the root background on every
		900	window move or resize.
		901
		902	Another example is C<load>, which can be quite slow.
		903
		904	In fact, urxvt itself encloses the whole expression in some kind of
		905	C<keep> block so it only is reevaluated as required.
		906
		907	Putting the blur into a C<keep> block will make sure the blur is only done
		908	once, while the C<rootalign> is still done each time the window moves.
		909
		910	rootalign keep { blur 10, root }
		911
		912	This leaves the question of how to force reevaluation of the block,
		913	in case the root background changes: If expression inside the block
		914	is sensitive to some event (root background changes, window geometry
		915	changes), then it will be reevaluated automatically as needed.
		916
		917	=cut
		918
		919	sub keep(&) {
		920	my $id = $_[0]+0;
		921
		922	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		923
		924	unless ($frame->[FR_CACHE]) {
		925	$frame->[FR_CACHE] = [ $_[0]() ];
		926
		927	my $self = $self;
		928	my $frame = $frame;
		929	Scalar::Util::weaken $frame;
		930	$self->compile_frame ($frame, sub {
		931	# clear this frame cache, also for all parents
		932	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		933	undef $frame->[FR_CACHE];
		934	}
		935
		936	$self->recalculate;
		937	});
		938	};
		939
		940	# in scalar context we always return the first original result, which
		941	# is not quite how perl works.
		942	wantarray
		943	? @{ $frame->[FR_CACHE] }
		944	: $frame->[FR_CACHE][0]
		945	}
		946
		947	# sub keep_clear() {
		948	# delete $self->{frame_cache};
84	}	949	# }
85		950
86	sub counter {	951	=back
87	$new->{again} = $_[0];	952
88	$self->{counter}++ + 0	953	=cut
89	}	954
90	}	955	}
91		956
92	sub parse_expr {	957	sub parse_expr {
93	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	958	my $expr = eval
		959	"sub {\n"
		960	. "package urxvt::bgdsl;\n"
		961	. "#line 0 'background expression'\n"
		962	. "$_[0]\n"
		963	. "}";
94	die if $@;	964	die if $@;
95	$expr	965	$expr
96	}	966	}
97		967
98	# compiles a parsed expression	968	# compiles a parsed expression
99	sub set_expr {	969	sub set_expr {
100	my ($self, $expr) = @_;	970	my ($self, $expr) = @_;
101		971
102	local $Data::Dumper::Deparse=1; use Data::Dumper; warn Dumper $expr;#d#	972	$self->{root} = []; # the outermost frame
103	$self->{expr} = $expr;	973	$self->{expr} = $expr;
104	$self->recalculate;	974	$self->recalculate;
105	}	975	}
106		976
		977	# takes a hash of sensitivity indicators and installs watchers
		978	sub compile_frame {
		979	my ($self, $frame, $cb) = @_;
		980
		981	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		982	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		983
		984	# don't keep stuff alive
		985	Scalar::Util::weaken $state;
		986
		987	if ($again->{nested}) {
		988	$state->{nested} = 1;
		989	} else {
		990	delete $state->{nested};
		991	}
		992
		993	if (my $interval = $again->{time}) {
		994	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		995	if $state->{time}[0] != $interval;
		996
		997	# callback might have changed, although we could just rule that out
		998	$state->{time}[1]->cb (sub {
		999	++$state->{counter};
		1000	$cb->();
		1001	});
		1002	} else {
		1003	delete $state->{time};
		1004	}
		1005
		1006	if ($again->{position}) {
		1007	$state->{position} = $self->on (position_change => $cb);
		1008	} else {
		1009	delete $state->{position};
		1010	}
		1011
		1012	if ($again->{size}) {
		1013	$state->{size} = $self->on (size_change => $cb);
		1014	} else {
		1015	delete $state->{size};
		1016	}
		1017
		1018	if ($again->{rootpmap}) {
		1019	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		1020	} else {
		1021	delete $state->{rootpmap};
		1022	}
		1023	}
		1024
107	# evaluate the current bg expression	1025	# evaluate the current bg expression
108	sub recalculate {	1026	sub recalculate {
109	my ($self) = @_;	1027	my ($arg_self) = @_;
110		1028
111	local $urxvt::bgdsl::vars::self = $self;	1029	# rate limit evaluation
112		1030
113	local $urxvt::bgdsl::vars::old = $self->{state};	1031	if ($arg_self->{next_refresh} > urxvt::NOW) {
114	local $urxvt::bgdsl::vars::new = my $state = $self->{state} = {};	1032	$arg_self->{next_refresh_timer} = urxvt::timer->new->after ($arg_self->{next_refresh} - urxvt::NOW)->cb (sub {
		1033	$arg_self->recalculate;
		1034	});
		1035	return;
		1036	}
115		1037
116	($urxvt::bgdsl::vars::x, $urxvt::bgdsl::vars::y, $urxvt::bgdsl::vars::w, $urxvt::bgdsl::vars::h) =	1038	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
117	$self->get_geometry;
118		1039
		1040	# set environment to evaluate user expression
		1041
		1042	local $self = $arg_self;
		1043	local $HOME = $ENV{HOME};
		1044	local $frame = $self->{root};
		1045
		1046	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
		1047
		1048	# evaluate user expression
		1049
119	my $img = eval { $self->{expr}->() };	1050	my @img = eval { $self->{expr}->() };
120	warn $@ if $@;#d#	1051	die $@ if $@;
		1052	die "background-expr did not return anything.\n" unless @img;
		1053	die "background-expr: expected image(s), got something else.\n"
		1054	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
121		1055
122	if (my $again = $state->{again}) {	1056	my $img = urxvt::bgdsl::merge @img;
123	warn $again;#d#	1057
124	$state->{again} = urxvt::timer->new->after ($again)->cb (sub { $self->recalculate });	1058	$frame->[FR_AGAIN]{size} = 1
		1059	if $img->repeat_mode != urxvt::RepeatNormal;
		1060
		1061	# if the expression is sensitive to external events, prepare reevaluation then
		1062	$self->compile_frame ($frame, sub { $arg_self->recalculate });
		1063
		1064	# clear stuff we no longer need
		1065
		1066	# unless (%{ $frame->[FR_STATE] }) {
		1067	# delete $self->{state};
		1068	# delete $self->{expr};
125	}	1069	# }
126		1070
127	# TODO: install handlers for geometry changes &c	1071	# set background pixmap
128		1072
129	warn $img;
130	$self->set_background ($img);	1073	$self->set_background ($img, $self->{border});
131	$self->scr_recolour (0);	1074	$self->scr_recolour (0);
132	$self->want_refresh;	1075	$self->want_refresh;
133	}	1076	}
134		1077
135	sub on_start {	1078	sub on_start {
136	my ($self) = @_;	1079	my ($self) = @_;
137		1080
		1081	my $expr = $self->x_resource ("%.expr")
		1082	or return;
		1083
		1084	$self->has_render
		1085	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1086
138	$self->set_expr (parse_expr $EXPR);	1087	$self->set_expr (parse_expr $expr);
		1088	$self->{border} = $self->x_resource_boolean ("%.border");
		1089
		1090	$MIN_INTERVAL = $self->x_resource ("%.interval");
139		1091
140	()	1092	()
141	}	1093	}
142		1094

Diff Legend

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

Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.1 by root, Mon Jun 4 21:39:56 2012 UTC vs. Revision 1.74 by root, Sat Jul 14 08:42:54 2012 UTC

Diff Legend

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.1 by root, Mon Jun 4 21:39:56 2012 UTC vs.
Revision 1.74 by root, Sat Jul 14 08:42:54 2012 UTC