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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.9 by root, Tue Jun 5 14:46:54 2012 UTC vs.
Revision 1.58 by root, Thu Jun 14 18:13:19 2012 UTC

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

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.9 by root, Tue Jun 5 14:46:54 2012 UTC vs. Revision 1.58 by root, Thu Jun 14 18:13:19 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.9 by root, Tue Jun 5 14:46:54 2012 UTC vs.
Revision 1.58 by root, Thu Jun 14 18:13:19 2012 UTC