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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.12 by root, Tue Jun 5 18:29:51 2012 UTC vs.
Revision 1.61 by root, Fri Jun 15 19:50:56 2012 UTC

…		…
1	#! perl	1	#! perl
2		2
3	#:META:RESOURCE:$$:string	3	#:META:X_RESOURCE:%.expr:string:background expression
		4	#:META:X_RESOURCE:%.border:boolean:respect the terminal border
		5	#:META:X_RESOURCE:%.interval:seconds:minimum time between updates
4		6
5	our $EXPR = 'move load "/root/pix/das_fette_schwein.jpg", repeat_wrap, X, Y';	7	=head1 NAME
6	$EXPR = '
7	rotate W, H, 50, 50, counter 1/59.95, repeat_mirror,
8	clip X, Y, W, H, repeat_mirror,
9	load "/root/pix/das_fette_schwein.jpg"
10	';
11	#$EXPR = 'blur root, 10, 10'
12	#$EXPR = 'blur move (root, -x, -y), 5, 5'
13	#resize load "/root/pix/das_fette_schwein.jpg", w, h
14		8
15	use Safe;	9	background - manage terminal background
16		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;
17	our ($bgdsl_self, $old, $new);	209	our ($self, $old, $new);
18	our ($l, $t, $w, $h);	210	our ($x, $y, $w, $h);
19		211
20	# enforce at leats this time between updates	212	# enforce at least this interval between updates
21	our $MIN_INTERVAL = 1/100;	213	our $MIN_INTERVAL = 6/59.951;
22		214
23	{	215	{
24	package urxvt::bgdsl; # background language	216	package urxvt::bgdsl; # background language
25		217
26	*repeat_black = \&urxvt::RepeatNone; #TODO wtf	218	use List::Util qw(min max sum shuffle);
27	*repeat_wrap = \&urxvt::RepeatNormal;	219
28	*repeat_pad = \&urxvt::RepeatPad;	220	=head2 PROVIDERS/GENERATORS
29	*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	}
30		253
31	sub load($) {	254	sub load($) {
32	my ($path) = @_;	255	my ($path) = @_;
33		256
34	$new->{load}{$path} = $old->{load}{$path} \|\| $bgdsl_self->new_img_from_file ($path);	257	$new->{load}{$path} = $old->{load}{$path} \|\| load_uc $path;
35	}	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
36		269
37	sub root() {	270	sub root() {
38	$new->{rootpmap_sensitive} = 1;	271	$new->{again}{rootpmap} = 1;
39	die "root op not supported, exg, we need you";	272	$self->new_img_from_root
40	}	273	}
41		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, 0, $_[0] \|\| 1, $_[1] \|\| 1);
		291	$img->fill ($colour);
		292	$img
		293	}
		294
		295	=item clone $img
		296
		297	Returns an exact copy of the image. This is useful if you want to have
		298	multiple copies of the same image to apply different effects to.
		299
		300	=cut
		301
42	# sub clone($) {	302	sub clone($) {
43	# $_[0]->clone	303	$_[0]->clone
44	# }	304	}
45		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	This function is called automatically when an expression returns multiple
		312	images.
		313
		314	=cut
		315
		316	sub merge(@) {
		317	return $_[0] unless $#_;
		318
		319	# rather annoyingly clumsy, but optimisation is for another time
		320
		321	my $x0 = +1e9;
		322	my $y0 = +1e9;
		323	my $x1 = -1e9;
		324	my $y1 = -1e9;
		325
		326	for (@_) {
		327	my ($x, $y, $w, $h) = $_->geometry;
		328
		329	$x0 = $x if $x0 > $x;
		330	$y0 = $y if $y0 > $y;
		331
		332	$x += $w;
		333	$y += $h;
		334
		335	$x1 = $x if $x1 < $x;
		336	$y1 = $y if $y1 < $y;
		337	}
		338
		339	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		340	$base->fill ([0, 0, 0, 0]);
		341
		342	$base->draw ($_)
		343	for @_;
		344
		345	$base
		346	}
		347
		348	=head2 TILING MODES
		349
		350	The following operators modify the tiling mode of an image, that is, the
		351	way that pixels outside the image area are painted when the image is used.
		352
		353	=over 4
		354
		355	=item tile $img
		356
		357	Tiles the whole plane with the image and returns this new image - or in
		358	other words, it returns a copy of the image in plane tiling mode.
		359
		360	Example: load an image and tile it over the background, without
		361	resizing. The C<tile> call is superfluous because C<load> already defaults
		362	to tiling mode.
		363
		364	tile load "mybg.png"
		365
		366	=item mirror $img
		367
		368	Similar to tile, but reflects the image each time it uses a new copy, so
		369	that top edges always touch top edges, right edges always touch right
		370	edges and so on (with normal tiling, left edges always touch right edges
		371	and top always touch bottom edges).
		372
		373	Example: load an image and mirror it over the background, avoiding sharp
		374	edges at the image borders at the expense of mirroring the image itself
		375
		376	mirror load "mybg.png"
		377
		378	=item pad $img
		379
		380	Takes an image and modifies it so that all pixels outside the image area
		381	become transparent. This mode is most useful when you want to place an
		382	image over another image or the background colour while leaving all
		383	background pixels outside the image unchanged.
		384
		385	Example: load an image and display it in the upper left corner. The rest
		386	of the space is left "empty" (transparent or whatever your compositor does
		387	in alpha mode, else background colour).
		388
		389	pad load "mybg.png"
		390
		391	=item extend $img
		392
		393	Extends the image over the whole plane, using the closest pixel in the
		394	area outside the image. This mode is mostly useful when you use more complex
		395	filtering operations and want the pixels outside the image to have the
		396	same values as the pixels near the edge.
		397
		398	Example: just for curiosity, how does this pixel extension stuff work?
		399
		400	extend move 50, 50, load "mybg.png"
		401
		402	=cut
		403
		404	sub pad($) {
		405	my $img = $_[0]->clone;
		406	$img->repeat_mode (urxvt::RepeatNone);
		407	$img
		408	}
		409
		410	sub tile($) {
		411	my $img = $_[0]->clone;
		412	$img->repeat_mode (urxvt::RepeatNormal);
		413	$img
		414	}
		415
		416	sub mirror($) {
		417	my $img = $_[0]->clone;
		418	$img->repeat_mode (urxvt::RepeatReflect);
		419	$img
		420	}
		421
		422	sub extend($) {
		423	my $img = $_[0]->clone;
		424	$img->repeat_mode (urxvt::RepeatPad);
		425	$img
		426	}
		427
		428	=back
		429
		430	=head2 VARIABLE VALUES
		431
		432	The following functions provide variable data such as the terminal window
		433	dimensions. They are not (Perl-) variables, they just return stuff that
		434	varies. Most of them make your expression sensitive to some events, for
		435	example using C<TW> (terminal width) means your expression is evaluated
		436	again when the terminal is resized.
		437
		438	=over 4
		439
		440	=item TX
		441
		442	=item TY
		443
		444	Return the X and Y coordinates of the terminal window (the terminal
		445	window is the full window by default, and the character area only when in
		446	border-respect mode).
		447
		448	Using these functions make your expression sensitive to window moves.
		449
		450	These functions are mainly useful to align images to the root window.
		451
		452	Example: load an image and align it so it looks as if anchored to the
		453	background.
		454
		455	move -TX, -TY, load "mybg.png"
		456
		457	=item TW
		458
		459	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		460	terminal window is the full window by default, and the character area only
		461	when in border-respect mode).
		462
		463	Using these functions make your expression sensitive to window resizes.
		464
		465	These functions are mainly useful to scale images, or to clip images to
		466	the window size to conserve memory.
		467
		468	Example: take the screen background, clip it to the window size, blur it a
		469	bit, align it to the window position and use it as background.
		470
		471	clip move -TX, -TY, once { blur 5, root }
		472
		473	=cut
		474
		475	sub TX() { $new->{again}{position} = 1; $x }
		476	sub TY() { $new->{again}{position} = 1; $y }
		477	sub TW() { $new->{again}{size} = 1; $w }
		478	sub TH() { $new->{again}{size} = 1; $h }
		479
		480	=item now
		481
		482	Returns the current time as (fractional) seconds since the epoch.
		483
		484	Using this expression does I<not> make your expression sensitive to time,
		485	but the next two functions do.
		486
		487	=item again $seconds
		488
		489	When this function is used the expression will be reevaluated again in
		490	C<$seconds> seconds.
		491
		492	Example: load some image and rotate it according to the time of day (as if it were
		493	the hour pointer of a clock). Update this image every minute.
		494
		495	again 60; rotate 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
		496
		497	=item counter $seconds
		498
		499	Like C<again>, but also returns an increasing counter value, starting at
		500	0, which might be useful for some simple animation effects.
		501
		502	=cut
		503
		504	sub now() { urxvt::NOW }
		505
		506	sub again($) {
		507	$new->{again}{time} = $_[0];
		508	}
		509
		510	sub counter($) {
		511	$new->{again}{time} = $_[0];
		512	$self->{counter} + 0
		513	}
		514
		515	=back
		516
		517	=head2 SHAPE CHANGING OPERATORS
		518
		519	The following operators modify the shape, size or position of the image.
		520
		521	=over 4
		522
		523	=item clip $img
		524
		525	=item clip $width, $height, $img
		526
		527	=item clip $x, $y, $width, $height, $img
		528
		529	Clips an image to the given rectangle. If the rectangle is outside the
		530	image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is
		531	larger than the image, then the tiling mode defines how the extra pixels
		532	will be filled.
		533
		534	If C<$x> an C<$y> are missing, then C<0> is assumed for both.
		535
		536	If C<$width> and C<$height> are missing, then the window size will be
		537	assumed.
		538
		539	Example: load an image, blur it, and clip it to the window size to save
		540	memory.
		541
		542	clip blur 10, load "mybg.png"
		543
		544	=cut
		545
46	sub clip($$$$$;$) {	546	sub clip($;$$;$$) {
		547	my $img = pop;
47	my $img = pop;	548	my $h = pop \|\| TH;
		549	my $w = pop \|\| TW;
48	$img->sub_rect ($_[0], $_[1], $_[2], $_[3], $_[4])	550	$img->sub_rect ($_[0], $_[1], $w, $h)
		551	}
		552
		553	=item scale $img
		554
		555	=item scale $size_factor, $img
		556
		557	=item scale $width_factor, $height_factor, $img
		558
		559	Scales the image by the given factors in horizontal
		560	(C<$width>) and vertical (C<$height>) direction.
		561
		562	If only one factor is give, it is used for both directions.
		563
		564	If no factors are given, scales the image to the window size without
		565	keeping aspect.
		566
		567	=item resize $width, $height, $img
		568
		569	Resizes the image to exactly C<$width> times C<$height> pixels.
		570
		571	=item fit $img
		572
		573	=item fit $width, $height, $img
		574
		575	Fits the image into the given C<$width> and C<$height> without changing
		576	aspect, or the terminal size. That means it will be shrunk or grown until
		577	the whole image fits into the given area, possibly leaving borders.
		578
		579	=item cover $img
		580
		581	=item cover $width, $height, $img
		582
		583	Similar to C<fit>, but shrinks or grows until all of the area is covered
		584	by the image, so instead of potentially leaving borders, it will cut off
		585	image data that doesn't fit.
		586
		587	=cut
		588
		589	sub scale($;$;$) {
		590	my $img = pop;
		591
		592	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
		593	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
		594	: $img->scale (TW, TH)
49	}	595	}
50		596
51	sub resize($$$) {	597	sub resize($$$) {
52	my $img = pop;	598	my $img = pop;
53	$img->scale ($_[0], $_[1])	599	$img->scale ($_[0], $_[1])
54	}	600	}
55		601
56	# TODO: ugly	602	sub fit($;$$) {
		603	my $img = pop;
		604	my $w = ($_[0] \|\| TW) / $img->w;
		605	my $h = ($_[1] \|\| TH) / $img->h;
		606	scale +(min $w, $h), $img
		607	}
		608
		609	sub cover($;$$) {
		610	my $img = pop;
		611	my $w = ($_[0] \|\| TW) / $img->w;
		612	my $h = ($_[1] \|\| TH) / $img->h;
		613	scale +(max $w, $h), $img
		614	}
		615
		616	=item move $dx, $dy, $img
		617
		618	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
		619	the vertical.
		620
		621	Example: move the image right by 20 pixels and down by 30.
		622
		623	move 20, 30, ...
		624
		625	=item align $xalign, $yalign, $img
		626
		627	Aligns the image according to a factor - C<0> means the image is moved to
		628	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		629	exactly centered and C<1> means it touches the right or bottom edge.
		630
		631	Example: remove any visible border around an image, center it vertically but move
		632	it to the right hand side.
		633
		634	align 1, 0.5, pad $img
		635
		636	=item center $img
		637
		638	=item center $width, $height, $img
		639
		640	Centers the image, i.e. the center of the image is moved to the center of
		641	the terminal window (or the box specified by C<$width> and C<$height> if
		642	given).
		643
		644	Example: load an image and center it.
		645
		646	center pad load "mybg.png"
		647
		648	=item rootalign $img
		649
		650	Moves the image so that it appears glued to the screen as opposed to the
		651	window. This gives the illusion of a larger area behind the window. It is
		652	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
		653	top left of the screen.
		654
		655	Example: load a background image, put it in mirror mode and root align it.
		656
		657	rootalign mirror load "mybg.png"
		658
		659	Example: take the screen background and align it, giving the illusion of
		660	transparency as long as the window isn't in front of other windows.
		661
		662	rootalign root
		663
		664	=cut
		665
57	sub move($$;$) {	666	sub move($$;$) {
58	my $img = pop;	667	my $img = pop->clone;
		668	$img->move ($_[0], $_[1]);
		669	$img
		670	}
		671
		672	sub align($;$$) {
		673	my $img = pop;
		674
		675	move $_[0] * (TW - $img->w),
		676	$_[1] * (TH - $img->h),
		677	$img
		678	}
		679
		680	sub center($;$$) {
		681	my $img = pop;
		682	my $w = $_[0] \|\| TW;
		683	my $h = $_[1] \|\| TH;
		684
		685	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		686	}
		687
		688	sub rootalign($) {
		689	move -TX, -TY, $_[0]
		690	}
		691
		692	=item rotate $center_x, $center_y, $degrees
		693
		694	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
		695	pointer at C<$center_x> and C<$center_y> (specified as factor of image
		696	width/height).
		697
		698	#TODO# new width, height, maybe more operators?
		699
		700	Example: rotate the image by 90 degrees
		701
		702	=cut
		703
		704	sub rotate($$$$) {
		705	my $img = pop;
59	$img->sub_rect (	706	$img->rotate (
60	$_[0], $_[1],
61	$img->w, $img->h,	707	$_[0] * ($img->w + $img->x),
62	$_[2],	708	$_[1] * ($img->h + $img->y),
		709	$_[2] * (3.14159265 / 180),
63	)	710	)
64	}	711	}
65		712
66	sub rotate($$$$$$;$) {	713	=back
67	my $img = pop;
68	$img->rotate (
69	$_[0],
70	$_[1],
71	$_[2] * $img->w * .01,
72	$_[3] * $img->h * .01,
73	$_[4] * (3.14159265 / 180),
74	$_[5],
75	)
76	}
77		714
78	sub blur($$$) {	715	=head2 COLOUR MODIFICATIONS
79	my ($rh, $rv, $img) = @_;
80		716
81	$img->blur ($rh, $rv);	717	The following operators change the pixels of the image.
82	}	718
		719	=over 4
		720
		721	=item contrast $factor, $img
		722
		723	=item contrast $r, $g, $b, $img
		724
		725	=item contrast $r, $g, $b, $a, $img
		726
		727	Adjusts the I<contrast> of an image.
		728
		729	The first form applies a single C<$factor> to red, green and blue, the
		730	second form applies separate factors to each colour channel, and the last
		731	form includes the alpha channel.
		732
		733	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		734	contrast.
		735
		736	Due to limitations in the underlying XRender extension, lowering contrast
		737	also reduces brightness, while increasing contrast currently also
		738	increases brightness.
		739
		740	=item brightness $bias, $img
		741
		742	=item brightness $r, $g, $b, $img
		743
		744	=item brightness $r, $g, $b, $a, $img
		745
		746	Adjusts the brightness of an image.
		747
		748	The first form applies a single C<$bias> to red, green and blue, the
		749	second form applies separate biases to each colour channel, and the last
		750	form includes the alpha channel.
		751
		752	Values less than 0 reduce brightness, while values larger than 0 increase
		753	it. Useful range is from -1 to 1 - the former results in a black, the
		754	latter in a white picture.
		755
		756	Due to idiosyncrasies in the underlying XRender extension, biases less
		757	than zero can be I<very> slow.
		758
		759	=cut
83		760
84	sub contrast($$;$$;$) {	761	sub contrast($$;$$;$) {
85	my $img = pop;	762	my $img = pop;
86	my ($r, $g, $b, $a) = @_;	763	my ($r, $g, $b, $a) = @_;
87		764
88	($g, $b) = ($r, $r) if @_ < 4;	765	($g, $b) = ($r, $r) if @_ < 3;
89	$a = 1 if @_ < 5;	766	$a = 1 if @_ < 4;
90		767
91	$img = $img->clone;	768	$img = $img->clone;
92	$img->contrast ($r, $g, $b, $a);	769	$img->contrast ($r, $g, $b, $a);
93	$img	770	$img
94	}	771	}
95		772
96	sub brightness($$;$$;$) {	773	sub brightness($$;$$;$) {
97	my $img = pop;	774	my $img = pop;
98	my ($r, $g, $b, $a) = @_;	775	my ($r, $g, $b, $a) = @_;
99		776
100	($g, $b) = ($r, $r) if @_ < 4;	777	($g, $b) = ($r, $r) if @_ < 3;
101	$a = 1 if @_ < 5;	778	$a = 1 if @_ < 4;
102		779
103	$img = $img->clone;	780	$img = $img->clone;
104	$img->brightness ($r, $g, $b, $a);	781	$img->brightness ($r, $g, $b, $a);
105	$img	782	$img
106	}	783	}
107		784
108	sub X() { $new->{position_sensitive} = 1; $l }	785	=item blur $radius, $img
109	sub Y() { $new->{position_sensitive} = 1; $t }
110	sub W() { $new->{size_sensitive} = 1; $w }
111	sub H() { $new->{size_sensitive} = 1; $h }
112		786
113	sub now() { urxvt::NOW }	787	=item blur $radius_horz, $radius_vert, $img
114		788
115	sub again($) {	789	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
		790	can also be specified separately.
		791
		792	Blurring is often I<very> slow, at least compared or other
		793	operators. Larger blur radii are slower than smaller ones, too, so if you
		794	don't want to freeze your screen for long times, start experimenting with
		795	low values for radius (<5).
		796
		797	=cut
		798
		799	sub blur($$;$) {
		800	my $img = pop;
		801	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
		802	}
		803
		804	=back
		805
		806	=head2 OTHER STUFF
		807
		808	Anything that didn't fit any of the other categories, even after applying
		809	force and closing our eyes.
		810
		811	=over 4
		812
		813	=item once { ... }
		814
		815	This function takes a code block as argument, that is, one or more
		816	statements enclosed by braces.
		817
		818	The trick is that this code block is only evaluated once - future calls
		819	will simply return the original image (yes, it should only be used with
		820	images).
		821
		822	This can be extremely useful to avoid redoign the same slow operations
		823	again and again- for example, if your background expression takes the root
		824	background, blurs it and then root-aligns it it would have to blur the
		825	root background on every window move or resize.
		826
		827	Putting the blur into a C<once> block will make sure the blur is only done
		828	once:
		829
		830	rootlign once { blur 10, root }
		831
		832	This leaves the question of how to force reevaluation of the block, in
		833	case the root background changes: Right now, all once blocks forget that
		834	they ahve been executed before each time the root background changes (if
		835	the expression is sensitive to that) or when C<once_again> is called.
		836
		837	=item once_again
		838
		839	Resets all C<once> block as if they had never been called, i.e. on the
		840	next call they will be reevaluated again.
		841
		842	=cut
		843
		844	sub once(&) {
		845	my $once = $self->{once_cache}{$_[0]+0} \|\|= do {
		846	local $new->{again};
		847	my @res = $_[0]();
		848	[$new->{again}, \@res]
		849	};
		850
116	$new->{again} = $_[0];	851	$new->{again} = {
117	}	852	%{ $new->{again} },
		853	%{ $once->[0] }
		854	};
118		855
119	sub counter($) {	856	# in scalar context we always return the first original result, which
120	$new->{again} = $_[0];	857	# is not quite how perl works.
121	$bgdsl_self->{counter} + 0	858	wantarray
		859	? @{ $once->[1] }
		860	: $once->[1][0]
122	}	861	}
		862
		863	sub once_again() {
		864	delete $self->{once_cache};
		865	}
		866
		867	=back
		868
		869	=cut
		870
123	}	871	}
124		872
125	sub parse_expr {	873	sub parse_expr {
126	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	874	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";
127	die if $@;	875	die if $@;
136	$self->recalculate;	884	$self->recalculate;
137	}	885	}
138		886
139	# evaluate the current bg expression	887	# evaluate the current bg expression
140	sub recalculate {	888	sub recalculate {
141	my ($self) = @_;	889	my ($arg_self) = @_;
142		890
143	# rate limit evaluation	891	# rate limit evaluation
144		892
145	if ($self->{next_refresh} > urxvt::NOW) {	893	if ($arg_self->{next_refresh} > urxvt::NOW) {
146	$self->{next_refresh_timer} = urxvt::timer->new->after ($self->{next_refresh} - urxvt::NOW)->cb (sub {	894	$arg_self->{next_refresh_timer} = urxvt::timer->new->after ($arg_self->{next_refresh} - urxvt::NOW)->cb (sub {
147	$self->recalculate;	895	$arg_self->recalculate;
148	});	896	});
149	return;	897	return;
150	}	898	}
151		899
152	$self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	900	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
153		901
154	# set environment to evaluate user expression	902	# set environment to evaluate user expression
155		903
156	local $bgdsl_self = $self;	904	local $self = $arg_self;
157		905
		906	local $HOME = $ENV{HOME};
158	local $old = $self->{state};	907	local $old = $self->{state};
159	local $new = my $state = $self->{state} = {};	908	local $new = my $state = $self->{state} = {};
160		909
161	($l, $t, $w, $h) =	910	($x, $y, $w, $h) =
162	$self->get_geometry;	911	$self->background_geometry ($self->{border});
163		912
164	# evaluate user expression	913	# evaluate user expression
165		914
166	my $img = eval { $self->{expr}->() };	915	my $img = eval { urxvt::bgdsl::merge $self->{expr}->() };
167	warn $@ if $@;#d#	916	die $@ if $@;
		917	die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";
168		918
169	# if the expression is sensitive to external events, prepare reevaluation then	919	# if the expression is sensitive to external events, prepare reevaluation then
170		920
171	my $repeat;
172
173	if (my $again = $state->{again}) {	921	my $again = delete $state->{again};
174	$repeat = 1;	922
		923	$again->{size} = 1
		924	if $img->repeat_mode != urxvt::RepeatNormal;
		925
		926	if (my $again = $again->{time}) {
		927	my $self = $self;
175	$state->{timer} = $again == $old->{again}	928	$state->{timer} = $again == $old->{again}
176	? $old->{timer}	929	? $old->{timer}
177	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {	930	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
178	++$self->{counter};	931	++$self->{counter};
179	$self->recalculate	932	$self->recalculate
180	});	933	});
181	}	934	}
182		935
183	if (delete $state->{position_sensitive}) {	936	if ($again->{position}) {
184	$repeat = 1;
185	$self->enable (position_change => sub { $_[0]->recalculate });	937	$self->enable (position_change => sub { $_[0]->recalculate });
186	} else {	938	} else {
187	$self->disable ("position_change");	939	$self->disable ("position_change");
188	}	940	}
189		941
190	if (delete $state->{size_sensitive}) {	942	if ($again->{size}) {
191	$repeat = 1;
192	$self->enable (size_change => sub { $_[0]->recalculate });	943	$self->enable (size_change => sub { $_[0]->recalculate });
193	} else {	944	} else {
194	$self->disable ("size_change");	945	$self->disable ("size_change");
195	}	946	}
196		947
197	if (delete $state->{rootpmap_sensitive}) {	948	if ($again->{rootpmap}) {
198	$repeat = 1;
199	$self->enable (rootpmap_change => sub { $_[0]->recalculate });	949	$self->enable (rootpmap_change => sub {
		950	delete $_[0]{once_cache}; # this will override once-block values from
		951	$_[0]->recalculate;
		952	});
200	} else {	953	} else {
201	$self->disable ("rootpmap_change");	954	$self->disable ("rootpmap_change");
202	}	955	}
203		956
204	# clear stuff we no longer need	957	# clear stuff we no longer need
205		958
206	%$old = ();	959	%$old = ();
207		960
208	unless ($repeat) {	961	unless (%$again) {
209	delete $self->{state};	962	delete $self->{state};
210	delete $self->{expr};	963	delete $self->{expr};
211	}	964	}
212		965
213	# prepare and set background pixmap	966	# set background pixmap
214		967
215	$img = $img->sub_rect (0, 0, $w, $h)
216	if $img->w != $w \|\| $img->h != $h;
217
218	$self->set_background ($img);	968	$self->set_background ($img, $self->{border});
219	$self->scr_recolour (0);	969	$self->scr_recolour (0);
220	$self->want_refresh;	970	$self->want_refresh;
221	}	971	}
222		972
223	sub on_start {	973	sub on_start {
224	my ($self) = @_;	974	my ($self) = @_;
225		975
		976	my $expr = $self->x_resource ("%.expr")
		977	or return;
		978
		979	$self->has_render
		980	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		981
226	$self->set_expr (parse_expr $EXPR);	982	$self->set_expr (parse_expr $expr);
		983	$self->{border} = $self->x_resource_boolean ("%.border");
		984
		985	$MIN_INTERVAL = $self->x_resource ("%.interval");
227		986
228	()	987	()
229	}	988	}
230		989

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.12 by root, Tue Jun 5 18:29:51 2012 UTC vs. Revision 1.61 by root, Fri Jun 15 19:50:56 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.12 by root, Tue Jun 5 18:29:51 2012 UTC vs.
Revision 1.61 by root, Fri Jun 15 19:50:56 2012 UTC