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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.15 by root, Tue Jun 5 22:46:50 2012 UTC vs.
Revision 1.56 by root, Thu Jun 14 17:06:57 2012 UTC

…		…
1	#! perl	1	#! perl
2		2
3	#:META:RESOURCE:$$:string:background expression	3	#:META:X_RESOURCE:%.expr:string:background expression
4	#:META:RESOURCE:$$-enable:boolean:some boolean	4	#:META:X_RESOURCE:%.border:boolean:respect the terminal border
		5	#:META:X_RESOURCE:%.interval:seconds:minimum time between updates
5		6
6	our $EXPR = 'move load "/root/pix/das_fette_schwein.jpg", repeat_wrap, X, Y';	7	=head1 NAME
7	$EXPR = '
8	rotate W, H, 50, 50, counter 1/59.95, repeat_mirror,
9	clip X, Y, W, H, repeat_mirror,
10	load "/root/pix/das_fette_schwein.jpg"
11	';
12	$EXPR = 'solid "red"';
13	#$EXPR = 'blur root, 10, 10'
14	#$EXPR = 'blur move (root, -x, -y), 5, 5'
15	#resize load "/root/pix/das_fette_schwein.jpg", w, h
16		8
17	use Safe;	9	background - manage terminal background
18		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 $HOME;
19	our ($bgdsl_self, $old, $new);	209	our ($self, $old, $new);
20	our ($l, $t, $w, $h);	210	our ($x, $y, $w, $h);
21		211
22	# enforce at leats this time between updates	212	# enforce at least this interval between updates
23	our $MIN_INTERVAL = 1/100;	213	our $MIN_INTERVAL = 6/59.951;
24		214
25	{	215	{
26	package urxvt::bgdsl; # background language	216	package urxvt::bgdsl; # background language
27		217
28	*repeat_black = \&urxvt::RepeatNone; #TODO wtf	218	use List::Util qw(min max sum shuffle);
29	*repeat_wrap = \&urxvt::RepeatNormal;
30	*repeat_pad = \&urxvt::RepeatPad;
31	*repeat_mirror = \&urxvt::RepeatReflect;
32		219
33	=head2 PROVIDERS/GENERATORS	220	=head2 PROVIDERS/GENERATORS
34		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
35	=over 4	226	=over 4
36		227
37	=item load $path	228	=item load $path
38		229
		230	Loads the image at the given C<$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 $path
		237
		238	Load uncached - same as load, but does not cache the image. This function
		239	is most useufl if you want to optimise a background expression in some
		240	way.
		241
39	=cut	242	=cut
		243
		244	sub load_uc($) {
		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	$img
		251	}
		252	}
40		253
41	sub load($) {	254	sub load($) {
42	my ($path) = @_;	255	my ($path) = @_;
43		256
44	$new->{load}{$path} = $old->{load}{$path} \|\| $bgdsl_self->new_img_from_file ($path);	257	$new->{load}{$path} = $old->{load}{$path} \|\| load_uc $path;
45	}	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
46		269
47	sub root() {	270	sub root() {
48	$new->{rootpmap_sensitive} = 1;	271	$new->{again}{rootpmap} = 1;
49	die "root op not supported, exg, we need you";	272	$self->new_img_from_root
50	}	273	}
		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<$height> are omitted, it creates a 1x1 image, which is
		283	useful for solid backgrounds or for use in filtering effects.
		284
		285	=cut
51		286
52	sub solid($;$$) {	287	sub solid($;$$) {
		288	my $colour = pop;
		289
53	my $img = $bgdsl_self->new_img (urxvt::PictStandardARGB32, $_[1] \|\| 1, $_[2] \|\| 1);	290	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);
54	$img->fill ($_[0]);	291	$img->fill ($colour);
55	$img	292	$img
56	}	293	}
57		294
		295	=item clone $img
		296
		297	Returns an exact copy of the image. This is useful if you want to have
		298	multiple copies of the same image to apply different effects to.
		299
		300	=cut
		301
		302	sub clone($) {
		303	$_[0]->clone
		304	}
		305
		306	=item merge $img ...
		307
		308	Takes any number of images and merges them together, creating a single image containing them all.
		309
		310	=cut
		311
		312	sub merge(@) {
		313	#TODO
		314	}
		315
		316	=head2 TILING MODES
		317
		318	The following operators modify the tiling mode of an image, that is, the
		319	way that pixels outside the image area are painted when the image is used.
		320
		321	=over 4
		322
		323	=item tile $img
		324
		325	Tiles the whole plane with the image and returns this new image - or in
		326	other words, it returns a copy of the image in plane tiling mode.
		327
		328	Example: load an image and tile it over the background, without
		329	resizing. The C<tile> call is superfluous because C<load> already defaults
		330	to tiling mode.
		331
		332	tile load "mybg.png"
		333
		334	=item mirror $img
		335
		336	Similar to tile, but reflects the image each time it uses a new copy, so
		337	that top edges always touch top edges, right edges always touch right
		338	edges and so on (with normal tiling, left edges always touch right edges
		339	and top always touch bottom edges).
		340
		341	Example: load an image and mirror it over the background, avoiding sharp
		342	edges at the image borders at the expense of mirroring the image itself
		343
		344	mirror load "mybg.png"
		345
		346	=item pad $img
		347
		348	Takes an image and modifies it so that all pixels outside the image area
		349	become transparent. This mode is most useful when you want to place an
		350	image over another image or the background colour while leaving all
		351	background pixels outside the image unchanged.
		352
		353	Example: load an image and display it in the upper left corner. The rest
		354	of the space is left "empty" (transparent or whatever your compositor does
		355	in alpha mode, else background colour).
		356
		357	pad load "mybg.png"
		358
		359	=item extend $img
		360
		361	Extends the image over the whole plane, using the closest pixel in the
		362	area outside the image. This mode is mostly useful when you use more complex
		363	filtering operations and want the pixels outside the image to have the
		364	same values as the pixels near the edge.
		365
		366	Example: just for curiosity, how does this pixel extension stuff work?
		367
		368	extend move 50, 50, load "mybg.png"
		369
		370	=cut
		371
		372	sub pad($) {
		373	my $img = $_[0]->clone;
		374	$img->repeat_mode (urxvt::RepeatNone);
		375	$img
		376	}
		377
		378	sub tile($) {
		379	my $img = $_[0]->clone;
		380	$img->repeat_mode (urxvt::RepeatNormal);
		381	$img
		382	}
		383
		384	sub mirror($) {
		385	my $img = $_[0]->clone;
		386	$img->repeat_mode (urxvt::RepeatReflect);
		387	$img
		388	}
		389
		390	sub extend($) {
		391	my $img = $_[0]->clone;
		392	$img->repeat_mode (urxvt::RepeatPad);
		393	$img
		394	}
		395
58	=back	396	=back
59		397
60	=head2 OPERATORS	398	=head2 VARIABLE VALUES
		399
		400	The following functions provide variable data such as the terminal window
		401	dimensions. They are not (Perl-) variables, they just return stuff that
		402	varies. Most of them make your expression sensitive to some events, for
		403	example using C<TW> (terminal width) means your expression is evaluated
		404	again when the terminal is resized.
61		405
62	=over 4	406	=over 4
63		407
64	=cut	408	=item TX
65		409
66	# sub clone($) {	410	=item TY
67	# $_[0]->clone	411
		412	Return the X and Y coordinates of the terminal window (the terminal
		413	window is the full window by default, and the character area only when in
		414	border-respect mode).
		415
		416	Using these functions make your expression sensitive to window moves.
		417
		418	These functions are mainly useful to align images to the root window.
		419
		420	Example: load an image and align it so it looks as if anchored to the
		421	background.
		422
		423	move -TX, -TY, load "mybg.png"
		424
		425	=item TW
		426
		427	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		428	terminal window is the full window by default, and the character area only
		429	when in border-respect mode).
		430
		431	Using these functions make your expression sensitive to window resizes.
		432
		433	These functions are mainly useful to scale images, or to clip images to
		434	the window size to conserve memory.
		435
		436	Example: take the screen background, clip it to the window size, blur it a
		437	bit, align it to the window position and use it as background.
		438
		439	clip move -TX, -TY, once { blur 5, root }
		440
		441	=cut
		442
		443	sub TX() { $new->{again}{position} = 1; $x }
		444	sub TY() { $new->{again}{position} = 1; $y }
		445	sub TW() { $new->{again}{size} = 1; $w }
		446	sub TH() { $new->{again}{size} = 1; $h }
		447
		448	=item now
		449
		450	Returns the current time as (fractional) seconds since the epoch.
		451
		452	Using this expression does I<not> make your expression sensitive to time,
		453	but the next two functions do.
		454
		455	=item again $seconds
		456
		457	When this function is used the expression will be reevaluated again in
		458	C<$seconds> seconds.
		459
		460	Example: load some image and rotate it according to the time of day (as if it were
		461	the hour pointer of a clock). Update this image every minute.
		462
		463	again 60; rotate 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
		464
		465	=item counter $seconds
		466
		467	Like C<again>, but also returns an increasing counter value, starting at
		468	0, which might be useful for some simple animation effects.
		469
		470	=cut
		471
		472	sub now() { urxvt::NOW }
		473
		474	sub again($) {
		475	$new->{again}{time} = $_[0];
68	# }	476	}
69		477
		478	sub counter($) {
		479	$new->{again}{time} = $_[0];
		480	$self->{counter} + 0
		481	}
		482
		483	=back
		484
		485	=head2 SHAPE CHANGING OPERATORS
		486
		487	The following operators modify the shape, size or position of the image.
		488
		489	=over 4
		490
		491	=item clip $img
		492
		493	=item clip $width, $height, $img
		494
		495	=item clip $x, $y, $width, $height, $img
		496
		497	Clips an image to the given rectangle. If the rectangle is outside the
		498	image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is
		499	larger than the image, then the tiling mode defines how the extra pixels
		500	will be filled.
		501
		502	If C<$x> an C<$y> are missing, then C<0> is assumed for both.
		503
		504	If C<$width> and C<$height> are missing, then the window size will be
		505	assumed.
		506
		507	Example: load an image, blur it, and clip it to the window size to save
		508	memory.
		509
		510	clip blur 10, load "mybg.png"
		511
		512	=cut
		513
70	sub clip($$$$$;$) {	514	sub clip($;$$;$$) {
		515	my $img = pop;
71	my $img = pop;	516	my $h = pop \|\| TH;
		517	my $w = pop \|\| TW;
72	$img->sub_rect ($_[0], $_[1], $_[2], $_[3], $_[4])	518	$img->sub_rect ($_[0], $_[1], $w, $h)
		519	}
		520
		521	=item scale $img
		522
		523	=item scale $size_factor, $img
		524
		525	=item scale $width_factor, $height_factor, $img
		526
		527	Scales the image by the given factors in horizontal
		528	(C<$width>) and vertical (C<$height>) direction.
		529
		530	If only one factor is give, it is used for both directions.
		531
		532	If no factors are given, scales the image to the window size without
		533	keeping aspect.
		534
		535	=item resize $width, $height, $img
		536
		537	Resizes the image to exactly C<$width> times C<$height> pixels.
		538
		539	=item fit $img
		540
		541	=item fit $width, $height, $img
		542
		543	Fits the image into the given C<$width> and C<$height> without changing
		544	aspect, or the terminal size. That means it will be shrunk or grown until
		545	the whole image fits into the given area, possibly leaving borders.
		546
		547	=item cover $img
		548
		549	=item cover $width, $height, $img
		550
		551	Similar to C<fit>, but shrinks or grows until all of the area is covered
		552	by the image, so instead of potentially leaving borders, it will cut off
		553	image data that doesn't fit.
		554
		555	=cut
		556
		557	sub scale($;$;$) {
		558	my $img = pop;
		559
		560	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
		561	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
		562	: $img->scale (TW, TH)
73	}	563	}
74		564
75	sub resize($$$) {	565	sub resize($$$) {
76	my $img = pop;	566	my $img = pop;
77	$img->scale ($_[0], $_[1])	567	$img->scale ($_[0], $_[1])
78	}	568	}
79		569
80	# TODO: ugly	570	sub fit($;$$) {
		571	my $img = pop;
		572	my $w = ($_[0] \|\| TW) / $img->w;
		573	my $h = ($_[1] \|\| TH) / $img->h;
		574	scale +(min $w, $h), $img
		575	}
		576
		577	sub cover($;$$) {
		578	my $img = pop;
		579	my $w = ($_[0] \|\| TW) / $img->w;
		580	my $h = ($_[1] \|\| TH) / $img->h;
		581	scale +(max $w, $h), $img
		582	}
		583
		584	=item move $dx, $dy, $img
		585
		586	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
		587	the vertical.
		588
		589	Example: move the image right by 20 pixels and down by 30.
		590
		591	move 20, 30, ...
		592
		593	=item align $xalign, $yalign, $img
		594
		595	Aligns the image according to a factor - C<0> means the image is moved to
		596	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		597	exactly centered and C<1> means it touches the right or bottom edge.
		598
		599	Example: remove any visible border around an image, center it vertically but move
		600	it to the right hand side.
		601
		602	align 1, 0.5, pad $img
		603
		604	=item center $img
		605
		606	=item center $width, $height, $img
		607
		608	Centers the image, i.e. the center of the image is moved to the center of
		609	the terminal window (or the box specified by C<$width> and C<$height> if
		610	given).
		611
		612	Example: load an image and center it.
		613
		614	center pad load "mybg.png"
		615
		616	=item rootalign $img
		617
		618	Moves the image so that it appears glued to the screen as opposed to the
		619	window. This gives the illusion of a larger area behind the window. It is
		620	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
		621	top left of the screen.
		622
		623	Example: load a background image, put it in mirror mode and root align it.
		624
		625	rootalign mirror load "mybg.png"
		626
		627	Example: take the screen background and align it, giving the illusion of
		628	transparency as long as the window isn't in front of other windows.
		629
		630	rootalign root
		631
		632	=cut
		633
81	sub move($$;$) {	634	sub move($$;$) {
82	my $img = pop;	635	my $img = pop->clone;
		636	$img->move ($_[0], $_[1]);
		637	$img
		638	}
		639
		640	sub align($;$$) {
		641	my $img = pop;
		642
		643	move $_[0] * (TW - $img->w),
		644	$_[1] * (TH - $img->h),
		645	$img
		646	}
		647
		648	sub center($;$$) {
		649	my $img = pop;
		650	my $w = $_[0] \|\| TW;
		651	my $h = $_[1] \|\| TH;
		652
		653	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		654	}
		655
		656	sub rootalign($) {
		657	move -TX, -TY, $_[0]
		658	}
		659
		660	=item rotate $center_x, $center_y, $degrees
		661
		662	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
		663	pointer at C<$center_x> and C<$center_y> (specified as factor of image
		664	width/height).
		665
		666	#TODO# new width, height, maybe more operators?
		667
		668	Example: rotate the image by 90 degrees
		669
		670	=cut
		671
		672	sub rotate($$$$) {
		673	my $img = pop;
83	$img->sub_rect (	674	$img->rotate (
84	$_[0], $_[1],	675	$_[0] * $img->w,
85	$img->w, $img->h,	676	$_[1] * $img->h,
86	$_[2],	677	$_[2] * (3.14159265 / 180),
87	)	678	)
88	}	679	}
89		680
90	sub rotate($$$$$$;$) {	681	=back
91	my $img = pop;
92	$img->rotate (
93	$_[0],
94	$_[1],
95	$_[2] * $img->w * .01,
96	$_[3] * $img->h * .01,
97	$_[4] * (3.14159265 / 180),
98	$_[5],
99	)
100	}
101		682
102	sub blur($$$) {	683	=head2 COLOUR MODIFICATIONS
103	my ($rh, $rv, $img) = @_;
104		684
105	$img->blur ($rh, $rv);	685	The following operators change the pixels of the image.
106	}	686
		687	=over 4
		688
		689	=item contrast $factor, $img
		690
		691	=item contrast $r, $g, $b, $img
		692
		693	=item contrast $r, $g, $b, $a, $img
		694
		695	Adjusts the I<contrast> of an image.
		696
		697	The first form applies a single C<$factor> to red, green and blue, the
		698	second form applies separate factors to each colour channel, and the last
		699	form includes the alpha channel.
		700
		701	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		702	contrast.
		703
		704	Due to limitations in the underlying XRender extension, lowering contrast
		705	also reduces brightness, while increasing contrast currently also
		706	increases brightness.
		707
		708	=item brightness $bias, $img
		709
		710	=item brightness $r, $g, $b, $img
		711
		712	=item brightness $r, $g, $b, $a, $img
		713
		714	Adjusts the brightness of an image.
		715
		716	The first form applies a single C<$bias> to red, green and blue, the
		717	second form applies separate biases to each colour channel, and the last
		718	form includes the alpha channel.
		719
		720	Values less than 0 reduce brightness, while values larger than 0 increase
		721	it. Useful range is from -1 to 1 - the former results in a black, the
		722	latter in a white picture.
		723
		724	Due to idiosyncrasies in the underlying XRender extension, biases less
		725	than zero can be I<very> slow.
		726
		727	=cut
107		728
108	sub contrast($$;$$;$) {	729	sub contrast($$;$$;$) {
109	my $img = pop;	730	my $img = pop;
110	my ($r, $g, $b, $a) = @_;	731	my ($r, $g, $b, $a) = @_;
111		732
112	($g, $b) = ($r, $r) if @_ < 4;	733	($g, $b) = ($r, $r) if @_ < 3;
113	$a = 1 if @_ < 5;	734	$a = 1 if @_ < 4;
114		735
115	$img = $img->clone;	736	$img = $img->clone;
116	$img->contrast ($r, $g, $b, $a);	737	$img->contrast ($r, $g, $b, $a);
117	$img	738	$img
118	}	739	}
119		740
120	sub brightness($$;$$;$) {	741	sub brightness($$;$$;$) {
121	my $img = pop;	742	my $img = pop;
122	my ($r, $g, $b, $a) = @_;	743	my ($r, $g, $b, $a) = @_;
123		744
124	($g, $b) = ($r, $r) if @_ < 4;	745	($g, $b) = ($r, $r) if @_ < 3;
125	$a = 1 if @_ < 5;	746	$a = 1 if @_ < 4;
126		747
127	$img = $img->clone;	748	$img = $img->clone;
128	$img->brightness ($r, $g, $b, $a);	749	$img->brightness ($r, $g, $b, $a);
129	$img	750	$img
130	}	751	}
131		752
132	sub X() { $new->{position_sensitive} = 1; $l }	753	=item blur $radius, $img
133	sub Y() { $new->{position_sensitive} = 1; $t }
134	sub W() { $new->{size_sensitive} = 1; $w }
135	sub H() { $new->{size_sensitive} = 1; $h }
136		754
137	sub now() { urxvt::NOW }	755	=item blur $radius_horz, $radius_vert, $img
138		756
139	sub again($) {	757	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
		758	can also be specified separately.
		759
		760	Blurring is often I<very> slow, at least compared or other
		761	operators. Larger blur radii are slower than smaller ones, too, so if you
		762	don't want to freeze your screen for long times, start experimenting with
		763	low values for radius (<5).
		764
		765	=cut
		766
		767	sub blur($$;$) {
		768	my $img = pop;
		769	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
		770	}
		771
		772	=back
		773
		774	=head2 OTHER STUFF
		775
		776	Anything that didn't fit any of the other categories, even after applying
		777	force and closing our eyes.
		778
		779	=over 4
		780
		781	=item once { ... }
		782
		783	This function takes a code block as argument, that is, one or more
		784	statements enclosed by braces.
		785
		786	The trick is that this code block is only evaluated once - future calls
		787	will simply return the original image (yes, it should only be used with
		788	images).
		789
		790	This can be extremely useful to avoid redoign the same slow operations
		791	again and again- for example, if your background expression takes the root
		792	background, blurs it and then root-aligns it it would have to blur the
		793	root background on every window move or resize.
		794
		795	Putting the blur into a C<once> block will make sure the blur is only done
		796	once:
		797
		798	rootlign once { blur 10, root }
		799
		800	This leaves the question of how to force reevaluation of the block, in
		801	case the root background changes: Right now, all once blocks forget that
		802	they ahve been executed before each time the root background changes (if
		803	the expression is sensitive to that) or when C<once_again> is called.
		804
		805	=item once_again
		806
		807	Resets all C<once> block as if they had never been called, i.e. on the
		808	next call they will be reevaluated again.
		809
		810	=cut
		811
		812	sub once(&) {
		813	my $once = $self->{once_cache}{$_[0]+0} \|\|= do {
		814	local $new->{again};
		815	my @res = $_[0]();
		816	[$new->{again}, \@res]
		817	};
		818
140	$new->{again} = $_[0];	819	$new->{again} = {
141	}	820	%{ $new->{again} },
		821	%{ $once->[0] }
		822	};
142		823
143	sub counter($) {	824	# in scalar context we always return the first original result, which
144	$new->{again} = $_[0];	825	# is not quite how perl works.
145	$bgdsl_self->{counter} + 0	826	wantarray
		827	? @{ $once->[1] }
		828	: $once->[1][0]
		829	}
		830
		831	sub once_again() {
		832	delete $self->{once_cache};
146	}	833	}
147		834
148	=back	835	=back
149		836
150	=cut	837	=cut
165	$self->recalculate;	852	$self->recalculate;
166	}	853	}
167		854
168	# evaluate the current bg expression	855	# evaluate the current bg expression
169	sub recalculate {	856	sub recalculate {
170	my ($self) = @_;	857	my ($arg_self) = @_;
171		858
172	# rate limit evaluation	859	# rate limit evaluation
173		860
174	if ($self->{next_refresh} > urxvt::NOW) {	861	if ($arg_self->{next_refresh} > urxvt::NOW) {
175	$self->{next_refresh_timer} = urxvt::timer->new->after ($self->{next_refresh} - urxvt::NOW)->cb (sub {	862	$arg_self->{next_refresh_timer} = urxvt::timer->new->after ($arg_self->{next_refresh} - urxvt::NOW)->cb (sub {
176	$self->recalculate;	863	$arg_self->recalculate;
177	});	864	});
178	return;	865	return;
179	}	866	}
180		867
181	$self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	868	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
182		869
183	# set environment to evaluate user expression	870	# set environment to evaluate user expression
184		871
185	local $bgdsl_self = $self;	872	local $self = $arg_self;
186		873
		874	local $HOME = $ENV{HOME};
187	local $old = $self->{state};	875	local $old = $self->{state};
188	local $new = my $state = $self->{state} = {};	876	local $new = my $state = $self->{state} = {};
189		877
190	($l, $t, $w, $h) =	878	($x, $y, $w, $h) =
191	$self->get_geometry;	879	$self->background_geometry ($self->{border});
192		880
193	# evaluate user expression	881	# evaluate user expression
194		882
195	my $img = eval { $self->{expr}->() };	883	my $img = eval { $self->{expr}->() };
196	warn $@ if $@;#d#	884	warn $@ if $@;#d#
197	die if !UNIVERSAL::isa $img, "urxvt::img";	885	die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";
198		886
199	# if the expression is sensitive to external events, prepare reevaluation then	887	# if the expression is sensitive to external events, prepare reevaluation then
200		888
201	my $repeat;
202
203	if (my $again = $state->{again}) {	889	my $again = delete $state->{again};
204	$repeat = 1;	890
		891	$again->{size} = 1
		892	if $img->repeat_mode != urxvt::RepeatNormal;
		893
		894	if (my $again = $again->{time}) {
		895	my $self = $self;
205	$state->{timer} = $again == $old->{again}	896	$state->{timer} = $again == $old->{again}
206	? $old->{timer}	897	? $old->{timer}
207	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {	898	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
208	++$self->{counter};	899	++$self->{counter};
209	$self->recalculate	900	$self->recalculate
210	});	901	});
211	}	902	}
212		903
213	if (delete $state->{position_sensitive}) {	904	if ($again->{position}) {
214	$repeat = 1;
215	$self->enable (position_change => sub { $_[0]->recalculate });	905	$self->enable (position_change => sub { $_[0]->recalculate });
216	} else {	906	} else {
217	$self->disable ("position_change");	907	$self->disable ("position_change");
218	}	908	}
219		909
220	if (delete $state->{size_sensitive}) {	910	if ($again->{size}) {
221	$repeat = 1;
222	$self->enable (size_change => sub { $_[0]->recalculate });	911	$self->enable (size_change => sub { $_[0]->recalculate });
223	} else {	912	} else {
224	$self->disable ("size_change");	913	$self->disable ("size_change");
225	}	914	}
226		915
227	if (delete $state->{rootpmap_sensitive}) {	916	if ($again->{rootpmap}) {
228	$repeat = 1;
229	$self->enable (rootpmap_change => sub { $_[0]->recalculate });	917	$self->enable (rootpmap_change => sub {
		918	delete $_[0]{once_cache}; # this will override once-block values from
		919	$_[0]->recalculate;
		920	});
230	} else {	921	} else {
231	$self->disable ("rootpmap_change");	922	$self->disable ("rootpmap_change");
232	}	923	}
233		924
234	# clear stuff we no longer need	925	# clear stuff we no longer need
235		926
236	%$old = ();	927	%$old = ();
237		928
238	unless ($repeat) {	929	unless (%$again) {
239	delete $self->{state};	930	delete $self->{state};
240	delete $self->{expr};	931	delete $self->{expr};
241	}	932	}
242		933
243	# prepare and set background pixmap	934	# set background pixmap
244		935
245	$img = $img->sub_rect (0, 0, $w, $h)
246	if $img->w != $w \|\| $img->h != $h;
247
248	$self->set_background ($img);	936	$self->set_background ($img, $self->{border});
249	$self->scr_recolour (0);	937	$self->scr_recolour (0);
250	$self->want_refresh;	938	$self->want_refresh;
251	}	939	}
252		940
253	sub on_start {	941	sub on_start {
254	my ($self) = @_;	942	my ($self) = @_;
255		943
		944	my $expr = $self->x_resource ("%.expr")
		945	or return;
		946
		947	$self->has_render
		948	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		949
256	$self->set_expr (parse_expr $EXPR);	950	$self->set_expr (parse_expr $expr);
		951	$self->{border} = $self->x_resource_boolean ("%.border");
		952
		953	$MIN_INTERVAL = $self->x_resource ("%.interval");
257		954
258	()	955	()
259	}	956	}
260		957

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.15 by root, Tue Jun 5 22:46:50 2012 UTC vs. Revision 1.56 by root, Thu Jun 14 17:06:57 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.15 by root, Tue Jun 5 22:46:50 2012 UTC vs.
Revision 1.56 by root, Thu Jun 14 17:06:57 2012 UTC