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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.4 by root, Tue Jun 5 13:39:26 2012 UTC vs.
Revision 1.57 by root, Thu Jun 14 18:06:15 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	$EXPR = 'rotate load "/root/pix/das_fette_schwein.jpg", W, H, 50, 50, counter 1/60, repeat_mirror';	4	#:META:X_RESOURCE:%.border:boolean:respect the terminal border
5	#$EXPR = 'blur root, 10, 10'	5	#:META:X_RESOURCE:%.interval:seconds:minimum time between updates
6	#$EXPR = 'blur move (root, -x, -y), 5, 5'
7	#resize load "/root/pix/das_fette_schwein.jpg", w, h
8		6
9	use Safe;	7	=head1 NAME
10		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 $HOME;
11	our ($bgdsl_self, $old, $new);	209	our ($self, $old, $new);
12	our ($l, $t, $w, $h);	210	our ($x, $y, $w, $h);
		211
		212	# enforce at least this interval between updates
		213	our $MIN_INTERVAL = 6/59.951;
13		214
14	{	215	{
15	package urxvt::bgdsl; # background language	216	package urxvt::bgdsl; # background language
16		217
17	*repeat_black = \&urxvt::RepeatNone; #TODO wtf	218	use List::Util qw(min max sum shuffle);
18	*repeat_wrap = \&urxvt::RepeatNormal;	219
19	*repeat_pad = \&urxvt::RepeatPad;	220	=head2 PROVIDERS/GENERATORS
20	*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	$img
		251	}
		252	}
21		253
22	sub load($) {	254	sub load($) {
23	my ($path) = @_;	255	my ($path) = @_;
24		256
25	$new->{load}{$path} = $old->{load}{$path} \|\| $bgdsl_self->new_img_from_file ($path);	257	$new->{load}{$path} = $old->{load}{$path} \|\| load_uc $path;
26	}	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
27		269
28	sub root() {	270	sub root() {
29	die "root op not supported, exg, we need you";	271	$new->{again}{rootpmap} = 1;
		272	$self->new_img_from_root
30	}	273	}
31		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<$height> are omitted, it creates a 1x1 image, which is
		283	useful for solid backgrounds or for use in filtering effects.
		284
		285	=cut
		286
		287	sub solid($;$$) {
		288	my $colour = pop;
		289
		290	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);
		291	$img->fill ($colour);
		292	$img
		293	}
		294
		295	=item clone $img
		296
		297	Returns an exact copy of the image. This is useful if you want to have
		298	multiple copies of the same image to apply different effects to.
		299
		300	=cut
		301
32	# sub clone($) {	302	sub clone($) {
33	# $_[0]->clone	303	$_[0]->clone
34	# }	304	}
35		305
36	sub subrect($$$$$;$) {	306	=item merge $img ...
37	$_[0]->sub_rect ($_[1], $_[2], $_[3], $_[4], $_[5])	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	#TODO
		315	}
		316
		317	=head2 TILING MODES
		318
		319	The following operators modify the tiling mode of an image, that is, the
		320	way that pixels outside the image area are painted when the image is used.
		321
		322	=over 4
		323
		324	=item tile $img
		325
		326	Tiles the whole plane with the image and returns this new image - or in
		327	other words, it returns a copy of the image in plane tiling mode.
		328
		329	Example: load an image and tile it over the background, without
		330	resizing. The C<tile> call is superfluous because C<load> already defaults
		331	to tiling mode.
		332
		333	tile load "mybg.png"
		334
		335	=item mirror $img
		336
		337	Similar to tile, but reflects the image each time it uses a new copy, so
		338	that top edges always touch top edges, right edges always touch right
		339	edges and so on (with normal tiling, left edges always touch right edges
		340	and top always touch bottom edges).
		341
		342	Example: load an image and mirror it over the background, avoiding sharp
		343	edges at the image borders at the expense of mirroring the image itself
		344
		345	mirror load "mybg.png"
		346
		347	=item pad $img
		348
		349	Takes an image and modifies it so that all pixels outside the image area
		350	become transparent. This mode is most useful when you want to place an
		351	image over another image or the background colour while leaving all
		352	background pixels outside the image unchanged.
		353
		354	Example: load an image and display it in the upper left corner. The rest
		355	of the space is left "empty" (transparent or whatever your compositor does
		356	in alpha mode, else background colour).
		357
		358	pad load "mybg.png"
		359
		360	=item extend $img
		361
		362	Extends the image over the whole plane, using the closest pixel in the
		363	area outside the image. This mode is mostly useful when you use more complex
		364	filtering operations and want the pixels outside the image to have the
		365	same values as the pixels near the edge.
		366
		367	Example: just for curiosity, how does this pixel extension stuff work?
		368
		369	extend move 50, 50, load "mybg.png"
		370
		371	=cut
		372
		373	sub pad($) {
		374	my $img = $_[0]->clone;
		375	$img->repeat_mode (urxvt::RepeatNone);
		376	$img
		377	}
		378
		379	sub tile($) {
		380	my $img = $_[0]->clone;
		381	$img->repeat_mode (urxvt::RepeatNormal);
		382	$img
		383	}
		384
		385	sub mirror($) {
		386	my $img = $_[0]->clone;
		387	$img->repeat_mode (urxvt::RepeatReflect);
		388	$img
		389	}
		390
		391	sub extend($) {
		392	my $img = $_[0]->clone;
		393	$img->repeat_mode (urxvt::RepeatPad);
		394	$img
		395	}
		396
		397	=back
		398
		399	=head2 VARIABLE VALUES
		400
		401	The following functions provide variable data such as the terminal window
		402	dimensions. They are not (Perl-) variables, they just return stuff that
		403	varies. Most of them make your expression sensitive to some events, for
		404	example using C<TW> (terminal width) means your expression is evaluated
		405	again when the terminal is resized.
		406
		407	=over 4
		408
		409	=item TX
		410
		411	=item TY
		412
		413	Return the X and Y coordinates of the terminal window (the terminal
		414	window is the full window by default, and the character area only when in
		415	border-respect mode).
		416
		417	Using these functions make your expression sensitive to window moves.
		418
		419	These functions are mainly useful to align images to the root window.
		420
		421	Example: load an image and align it so it looks as if anchored to the
		422	background.
		423
		424	move -TX, -TY, load "mybg.png"
		425
		426	=item TW
		427
		428	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		429	terminal window is the full window by default, and the character area only
		430	when in border-respect mode).
		431
		432	Using these functions make your expression sensitive to window resizes.
		433
		434	These functions are mainly useful to scale images, or to clip images to
		435	the window size to conserve memory.
		436
		437	Example: take the screen background, clip it to the window size, blur it a
		438	bit, align it to the window position and use it as background.
		439
		440	clip move -TX, -TY, once { blur 5, root }
		441
		442	=cut
		443
		444	sub TX() { $new->{again}{position} = 1; $x }
		445	sub TY() { $new->{again}{position} = 1; $y }
		446	sub TW() { $new->{again}{size} = 1; $w }
		447	sub TH() { $new->{again}{size} = 1; $h }
		448
		449	=item now
		450
		451	Returns the current time as (fractional) seconds since the epoch.
		452
		453	Using this expression does I<not> make your expression sensitive to time,
		454	but the next two functions do.
		455
		456	=item again $seconds
		457
		458	When this function is used the expression will be reevaluated again in
		459	C<$seconds> seconds.
		460
		461	Example: load some image and rotate it according to the time of day (as if it were
		462	the hour pointer of a clock). Update this image every minute.
		463
		464	again 60; rotate 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
		465
		466	=item counter $seconds
		467
		468	Like C<again>, but also returns an increasing counter value, starting at
		469	0, which might be useful for some simple animation effects.
		470
		471	=cut
		472
		473	sub now() { urxvt::NOW }
		474
		475	sub again($) {
		476	$new->{again}{time} = $_[0];
		477	}
		478
		479	sub counter($) {
		480	$new->{again}{time} = $_[0];
		481	$self->{counter} + 0
		482	}
		483
		484	=back
		485
		486	=head2 SHAPE CHANGING OPERATORS
		487
		488	The following operators modify the shape, size or position of the image.
		489
		490	=over 4
		491
		492	=item clip $img
		493
		494	=item clip $width, $height, $img
		495
		496	=item clip $x, $y, $width, $height, $img
		497
		498	Clips an image to the given rectangle. If the rectangle is outside the
		499	image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is
		500	larger than the image, then the tiling mode defines how the extra pixels
		501	will be filled.
		502
		503	If C<$x> an C<$y> are missing, then C<0> is assumed for both.
		504
		505	If C<$width> and C<$height> are missing, then the window size will be
		506	assumed.
		507
		508	Example: load an image, blur it, and clip it to the window size to save
		509	memory.
		510
		511	clip blur 10, load "mybg.png"
		512
		513	=cut
		514
		515	sub clip($;$$;$$) {
		516	my $img = pop;
		517	my $h = pop \|\| TH;
		518	my $w = pop \|\| TW;
		519	$img->sub_rect ($_[0], $_[1], $w, $h)
		520	}
		521
		522	=item scale $img
		523
		524	=item scale $size_factor, $img
		525
		526	=item scale $width_factor, $height_factor, $img
		527
		528	Scales the image by the given factors in horizontal
		529	(C<$width>) and vertical (C<$height>) direction.
		530
		531	If only one factor is give, it is used for both directions.
		532
		533	If no factors are given, scales the image to the window size without
		534	keeping aspect.
		535
		536	=item resize $width, $height, $img
		537
		538	Resizes the image to exactly C<$width> times C<$height> pixels.
		539
		540	=item fit $img
		541
		542	=item fit $width, $height, $img
		543
		544	Fits the image into the given C<$width> and C<$height> without changing
		545	aspect, or the terminal size. That means it will be shrunk or grown until
		546	the whole image fits into the given area, possibly leaving borders.
		547
		548	=item cover $img
		549
		550	=item cover $width, $height, $img
		551
		552	Similar to C<fit>, but shrinks or grows until all of the area is covered
		553	by the image, so instead of potentially leaving borders, it will cut off
		554	image data that doesn't fit.
		555
		556	=cut
		557
		558	sub scale($;$;$) {
		559	my $img = pop;
		560
		561	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
		562	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
		563	: $img->scale (TW, TH)
38	}	564	}
39		565
40	sub resize($$$) {	566	sub resize($$$) {
41	$_[0]->scale ($_[1], $_[2])	567	my $img = pop;
		568	$img->scale ($_[0], $_[1])
42	}	569	}
43		570
		571	sub fit($;$$) {
		572	my $img = pop;
		573	my $w = ($_[0] \|\| TW) / $img->w;
		574	my $h = ($_[1] \|\| TH) / $img->h;
		575	scale +(min $w, $h), $img
		576	}
		577
		578	sub cover($;$$) {
		579	my $img = pop;
		580	my $w = ($_[0] \|\| TW) / $img->w;
		581	my $h = ($_[1] \|\| TH) / $img->h;
		582	scale +(max $w, $h), $img
		583	}
		584
		585	=item move $dx, $dy, $img
		586
		587	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
		588	the vertical.
		589
		590	Example: move the image right by 20 pixels and down by 30.
		591
		592	move 20, 30, ...
		593
		594	=item align $xalign, $yalign, $img
		595
		596	Aligns the image according to a factor - C<0> means the image is moved to
		597	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		598	exactly centered and C<1> means it touches the right or bottom edge.
		599
		600	Example: remove any visible border around an image, center it vertically but move
		601	it to the right hand side.
		602
		603	align 1, 0.5, pad $img
		604
		605	=item center $img
		606
		607	=item center $width, $height, $img
		608
		609	Centers the image, i.e. the center of the image is moved to the center of
		610	the terminal window (or the box specified by C<$width> and C<$height> if
		611	given).
		612
		613	Example: load an image and center it.
		614
		615	center pad load "mybg.png"
		616
		617	=item rootalign $img
		618
		619	Moves the image so that it appears glued to the screen as opposed to the
		620	window. This gives the illusion of a larger area behind the window. It is
		621	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
		622	top left of the screen.
		623
		624	Example: load a background image, put it in mirror mode and root align it.
		625
		626	rootalign mirror load "mybg.png"
		627
		628	Example: take the screen background and align it, giving the illusion of
		629	transparency as long as the window isn't in front of other windows.
		630
		631	rootalign root
		632
		633	=cut
		634
44	sub move($$$;$) {	635	sub move($$;$) {
45	# TODO: must be simpler	636	my $img = pop->clone;
46	$_[0]->transform ($_[0]->w, $_[0]->h,	637	$img->move ($_[0], $_[1]);
47	1, 0, $_[1],	638	$img
48	0, 1, $_[2],	639	}
49	0, 0, 1,	640
50	$_[3],	641	sub align($;$$) {
		642	my $img = pop;
		643
		644	move $_[0] * (TW - $img->w),
		645	$_[1] * (TH - $img->h),
		646	$img
		647	}
		648
		649	sub center($;$$) {
		650	my $img = pop;
		651	my $w = $_[0] \|\| TW;
		652	my $h = $_[1] \|\| TH;
		653
		654	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		655	}
		656
		657	sub rootalign($) {
		658	move -TX, -TY, $_[0]
		659	}
		660
		661	=item rotate $center_x, $center_y, $degrees
		662
		663	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
		664	pointer at C<$center_x> and C<$center_y> (specified as factor of image
		665	width/height).
		666
		667	#TODO# new width, height, maybe more operators?
		668
		669	Example: rotate the image by 90 degrees
		670
		671	=cut
		672
		673	sub rotate($$$$) {
		674	my $img = pop;
		675	$img->rotate (
		676	$_[0] * $img->w,
		677	$_[1] * $img->h,
		678	$_[2] * (3.14159265 / 180),
51	)	679	)
52	}	680	}
53		681
54	sub rotate($$$$$$;$) {	682	=back
55	$_[0]->rotate (
56	$_[1],
57	$_[2],
58	$_[3] * $_[0]->w * .01,
59	$_[4] * $_[0]->h * .01,
60	$_[5] * (3.14159265 / 180),
61	$_[6],
62	)
63	}
64		683
65	sub blur($$$) {	684	=head2 COLOUR MODIFICATIONS
66	my ($img, $rh, $rv) = @_;
67		685
68	$img = $img->clone;	686	The following operators change the pixels of the image.
69	$img->blur ($rh, $rv);	687
70	$img	688	=over 4
71	}	689
		690	=item contrast $factor, $img
		691
		692	=item contrast $r, $g, $b, $img
		693
		694	=item contrast $r, $g, $b, $a, $img
		695
		696	Adjusts the I<contrast> of an image.
		697
		698	The first form applies a single C<$factor> to red, green and blue, the
		699	second form applies separate factors to each colour channel, and the last
		700	form includes the alpha channel.
		701
		702	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		703	contrast.
		704
		705	Due to limitations in the underlying XRender extension, lowering contrast
		706	also reduces brightness, while increasing contrast currently also
		707	increases brightness.
		708
		709	=item brightness $bias, $img
		710
		711	=item brightness $r, $g, $b, $img
		712
		713	=item brightness $r, $g, $b, $a, $img
		714
		715	Adjusts the brightness of an image.
		716
		717	The first form applies a single C<$bias> to red, green and blue, the
		718	second form applies separate biases to each colour channel, and the last
		719	form includes the alpha channel.
		720
		721	Values less than 0 reduce brightness, while values larger than 0 increase
		722	it. Useful range is from -1 to 1 - the former results in a black, the
		723	latter in a white picture.
		724
		725	Due to idiosyncrasies in the underlying XRender extension, biases less
		726	than zero can be I<very> slow.
		727
		728	=cut
72		729
73	sub contrast($$;$$;$) {	730	sub contrast($$;$$;$) {
		731	my $img = pop;
74	my ($img, $r, $g, $b, $a) = @_;	732	my ($r, $g, $b, $a) = @_;
75		733
76	($g, $b) = ($r, $r) if @_ < 4;	734	($g, $b) = ($r, $r) if @_ < 3;
77	$a = 1 if @_ < 5;	735	$a = 1 if @_ < 4;
78		736
79	$img = $img->clone;	737	$img = $img->clone;
80	$img->contrast ($r, $g, $b, $a);	738	$img->contrast ($r, $g, $b, $a);
81	$img	739	$img
82	}	740	}
83		741
84	sub brightness($$;$$;$) {	742	sub brightness($$;$$;$) {
		743	my $img = pop;
85	my ($img, $r, $g, $b, $a) = @_;	744	my ($r, $g, $b, $a) = @_;
86		745
87	($g, $b) = ($r, $r) if @_ < 4;	746	($g, $b) = ($r, $r) if @_ < 3;
88	$a = 1 if @_ < 5;	747	$a = 1 if @_ < 4;
89		748
90	$img = $img->clone;	749	$img = $img->clone;
91	$img->brightness ($r, $g, $b, $a);	750	$img->brightness ($r, $g, $b, $a);
92	$img	751	$img
93	}	752	}
94		753
95	sub X() { $new->{position_sensitive} = 1; $l }	754	=item blur $radius, $img
96	sub Y() { $new->{position_sensitive} = 1; $t }
97	sub W() { $new->{size_sensitive} = 1; $w }
98	sub H() { $new->{size_sensitive} = 1; $h }
99		755
100	sub now() { urxvt::NOW }	756	=item blur $radius_horz, $radius_vert, $img
101		757
102	sub again($) {	758	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
		759	can also be specified separately.
		760
		761	Blurring is often I<very> slow, at least compared or other
		762	operators. Larger blur radii are slower than smaller ones, too, so if you
		763	don't want to freeze your screen for long times, start experimenting with
		764	low values for radius (<5).
		765
		766	=cut
		767
		768	sub blur($$;$) {
		769	my $img = pop;
		770	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
		771	}
		772
		773	=back
		774
		775	=head2 OTHER STUFF
		776
		777	Anything that didn't fit any of the other categories, even after applying
		778	force and closing our eyes.
		779
		780	=over 4
		781
		782	=item once { ... }
		783
		784	This function takes a code block as argument, that is, one or more
		785	statements enclosed by braces.
		786
		787	The trick is that this code block is only evaluated once - future calls
		788	will simply return the original image (yes, it should only be used with
		789	images).
		790
		791	This can be extremely useful to avoid redoign the same slow operations
		792	again and again- for example, if your background expression takes the root
		793	background, blurs it and then root-aligns it it would have to blur the
		794	root background on every window move or resize.
		795
		796	Putting the blur into a C<once> block will make sure the blur is only done
		797	once:
		798
		799	rootlign once { blur 10, root }
		800
		801	This leaves the question of how to force reevaluation of the block, in
		802	case the root background changes: Right now, all once blocks forget that
		803	they ahve been executed before each time the root background changes (if
		804	the expression is sensitive to that) or when C<once_again> is called.
		805
		806	=item once_again
		807
		808	Resets all C<once> block as if they had never been called, i.e. on the
		809	next call they will be reevaluated again.
		810
		811	=cut
		812
		813	sub once(&) {
		814	my $once = $self->{once_cache}{$_[0]+0} \|\|= do {
		815	local $new->{again};
		816	my @res = $_[0]();
		817	[$new->{again}, \@res]
		818	};
		819
103	$new->{again} = $_[0];	820	$new->{again} = {
104	}	821	%{ $new->{again} },
		822	%{ $once->[0] }
		823	};
105		824
106	sub counter($) {	825	# in scalar context we always return the first original result, which
107	$new->{again} = $_[0];	826	# is not quite how perl works.
108	$bgdsl_self->{counter}++ + 0	827	wantarray
		828	? @{ $once->[1] }
		829	: $once->[1][0]
109	}	830	}
		831
		832	sub once_again() {
		833	delete $self->{once_cache};
		834	}
		835
		836	=back
		837
		838	=cut
		839
110	}	840	}
111		841
112	sub parse_expr {	842	sub parse_expr {
113	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	843	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";
114	die if $@;	844	die if $@;
123	$self->recalculate;	853	$self->recalculate;
124	}	854	}
125		855
126	# evaluate the current bg expression	856	# evaluate the current bg expression
127	sub recalculate {	857	sub recalculate {
128	my ($self) = @_;	858	my ($arg_self) = @_;
129		859
130	local $bgdsl_self = $self;	860	# rate limit evaluation
131		861
		862	if ($arg_self->{next_refresh} > urxvt::NOW) {
		863	$arg_self->{next_refresh_timer} = urxvt::timer->new->after ($arg_self->{next_refresh} - urxvt::NOW)->cb (sub {
		864	$arg_self->recalculate;
		865	});
		866	return;
		867	}
		868
		869	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
		870
		871	# set environment to evaluate user expression
		872
		873	local $self = $arg_self;
		874
		875	local $HOME = $ENV{HOME};
132	local $old = $self->{state};	876	local $old = $self->{state};
133	local $new = my $state = $self->{state} = {};	877	local $new = my $state = $self->{state} = {};
134		878
135	($l, $t, $w, $h) =	879	($x, $y, $w, $h) =
136	$self->get_geometry;	880	$self->background_geometry ($self->{border});
		881
		882	# evaluate user expression
137		883
138	my $img = eval { $self->{expr}->() };	884	my $img = eval { $self->{expr}->() };
139	warn $@ if $@;#d#	885	warn $@ if $@;#d#
		886	die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";
140		887
141	my $repeat;	888	# if the expression is sensitive to external events, prepare reevaluation then
142		889
143	if (my $again = $state->{again}) {	890	my $again = delete $state->{again};
144	$repeat = 1;
145	$state->{again} = urxvt::timer->new->after ($again)->cb (sub { $self->recalculate });
146	}
147		891
148	if (delete $state->{position_sensitive}) {	892	$again->{size} = 1
149	$repeat = 1;	893	if $img->repeat_mode != urxvt::RepeatNormal;
		894
		895	if (my $again = $again->{time}) {
		896	my $self = $self;
		897	$state->{timer} = $again == $old->{again}
		898	? $old->{timer}
		899	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
		900	++$self->{counter};
		901	$self->recalculate
		902	});
		903	}
		904
		905	if ($again->{position}) {
150	$self->enable (position_change => sub { $_[0]->recalculate });	906	$self->enable (position_change => sub { $_[0]->recalculate });
151	} else {	907	} else {
152	$self->disable ("position_change");	908	$self->disable ("position_change");
153	}	909	}
154		910
155	if (delete $state->{size_sensitive}) {	911	if ($again->{size}) {
156	$repeat = 1;
157	$self->enable (size_change => sub { $_[0]->recalculate });	912	$self->enable (size_change => sub { $_[0]->recalculate });
158	} else {	913	} else {
159	$self->disable ("size_change");	914	$self->disable ("size_change");
160	}	915	}
161		916
162	$img = $img->sub_rect (0, 0, $w, $h)	917	if ($again->{rootpmap}) {
163	if $img->w != $w \|\| $img->h != $h;	918	$self->enable (rootpmap_change => sub {
		919	delete $_[0]{once_cache}; # this will override once-block values from
		920	$_[0]->recalculate;
		921	});
		922	} else {
		923	$self->disable ("rootpmap_change");
		924	}
164		925
		926	# clear stuff we no longer need
		927
		928	%$old = ();
		929
		930	unless (%$again) {
		931	delete $self->{state};
		932	delete $self->{expr};
		933	}
		934
		935	# set background pixmap
		936
165	$self->set_background ($img);	937	$self->set_background ($img, $self->{border});
166	$self->scr_recolour (0);	938	$self->scr_recolour (0);
167	$self->want_refresh;	939	$self->want_refresh;
168	}	940	}
169		941
170	sub on_start {	942	sub on_start {
171	my ($self) = @_;	943	my ($self) = @_;
172		944
		945	my $expr = $self->x_resource ("%.expr")
		946	or return;
		947
		948	$self->has_render
		949	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		950
173	$self->set_expr (parse_expr $EXPR);	951	$self->set_expr (parse_expr $expr);
		952	$self->{border} = $self->x_resource_boolean ("%.border");
		953
		954	$MIN_INTERVAL = $self->x_resource ("%.interval");
174		955
175	()	956	()
176	}	957	}
177		958

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.4 by root, Tue Jun 5 13:39:26 2012 UTC vs. Revision 1.57 by root, Thu Jun 14 18:06:15 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.4 by root, Tue Jun 5 13:39:26 2012 UTC vs.
Revision 1.57 by root, Thu Jun 14 18:06:15 2012 UTC