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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.13 by root, Tue Jun 5 19:32:29 2012 UTC vs.
Revision 1.75 by root, Fri Aug 10 20:07:11 2012 UTC

1	#! perl	1	#! perl
2		2
3	#:META:RESOURCE:$$:string:background expression	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
17	our ($bgdsl_self, $old, $new);	11	=head1 SYNOPSIS
		12
		13	urxvt --background-expr 'background expression'
		14	--background-border
		15	--background-interval seconds
		16
		17	=head1 QUICK AND DIRTY CHEAT SHEET
		18
		19	Just load a random jpeg image and tile the background with it without
		20	scaling or anything else:
		21
		22	load "/path/to/img.jpg"
		23
		24	The same, but use mirroring/reflection instead of tiling:
		25
		26	mirror load "/path/to/img.jpg"
		27
		28	Load an image and scale it to exactly fill the terminal window:
		29
		30	scale keep { load "/path/to/img.jpg" }
		31
		32	Implement pseudo-transparency by using a suitably-aligned root pixmap
		33	as window background:
		34
		35	rootalign root
		36
		37	Likewise, but keep a blurred copy:
		38
		39	rootalign keep { blur 10, root }
		40
		41	=head1 DESCRIPTION
		42
		43	This extension manages the terminal background by creating a picture that
		44	is behind the text, replacing the normal background colour.
		45
		46	It does so by evaluating a Perl expression that I<calculates> the image on
		47	the fly, for example, by grabbing the root background or loading a file.
		48
		49	While the full power of Perl is available, the operators have been design
		50	to be as simple as possible.
		51
		52	For example, to load an image and scale it to the window size, you would
		53	use:
		54
		55	urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
		56
		57	Or specified as a X resource:
		58
		59	URxvt.background-expr: scale keep { load "/path/to/mybg.png" }
		60
		61	=head1 THEORY OF OPERATION
		62
		63	At startup, just before the window is mapped for the first time, the
		64	expression is evaluated and must yield an image. The image is then
		65	extended as necessary to cover the whole terminal window, and is set as a
		66	background pixmap.
		67
		68	If the image contains an alpha channel, then it will be used as-is in
		69	visuals that support alpha channels (for example, for a compositing
		70	manager). In other visuals, the terminal background colour will be used to
		71	replace any transparency.
		72
		73	When the expression relies, directly or indirectly, on the window size,
		74	position, the root pixmap, or a timer, then it will be remembered. If not,
		75	then it will be removed.
		76
		77	If any of the parameters that the expression relies on changes (when the
		78	window is moved or resized, its position or size changes; when the root
		79	pixmap is replaced by another one the root background changes; or when the
		80	timer elapses), then the expression will be evaluated again.
		81
		82	For example, an expression such as C<scale keep { load "$HOME/mybg.png"
		83	}> scales the image to the window size, so it relies on the window size
		84	and will be reevaluated each time it is changed, but not when it moves for
		85	example. That ensures that the picture always fills the terminal, even
		86	after its size changes.
		87
		88	=head2 EXPRESSIONS
		89
		90	Expressions are normal Perl expressions, in fact, they are Perl blocks -
		91	which means you could use multiple lines and statements:
		92
		93	scale keep {
		94	again 3600;
		95	if (localtime now)[6]) {
		96	return load "$HOME/weekday.png";
		97	} else {
		98	return load "$HOME/sunday.png";
		99	}
		100	}
		101
		102	This inner expression is evaluated once per hour (and whenever the
		103	terminal window is resized). It sets F<sunday.png> as background on
		104	Sundays, and F<weekday.png> on all other days.
		105
		106	Fortunately, we expect that most expressions will be much simpler, with
		107	little Perl knowledge needed.
		108
		109	Basically, you always start with a function that "generates" an image
		110	object, such as C<load>, which loads an image from disk, or C<root>, which
		111	returns the root window background image:
		112
		113	load "$HOME/mypic.png"
		114
		115	The path is usually specified as a quoted string (the exact rules can be
		116	found in the L<perlop> manpage). The F<$HOME> at the beginning of the
		117	string is expanded to the home directory.
		118
		119	Then you prepend one or more modifiers or filtering expressions, such as
		120	C<scale>:
		121
		122	scale load "$HOME/mypic.png"
		123
		124	Just like a mathematical expression with functions, you should read these
		125	expressions from right to left, as the C<load> is evaluated first, and
		126	its result becomes the argument to the C<scale> function.
		127
		128	Many operators also allow some parameters preceding the input image
		129	that modify its behaviour. For example, C<scale> without any additional
		130	arguments scales the image to size of the terminal window. If you specify
		131	an additional argument, it uses it as a scale factor (multiply by 100 to
		132	get a percentage):
		133
		134	scale 2, load "$HOME/mypic.png"
		135
		136	This enlarges the image by a factor of 2 (200%). As you can see, C<scale>
		137	has now two arguments, the C<200> and the C<load> expression, while
		138	C<load> only has one argument. Arguments are separated from each other by
		139	commas.
		140
		141	Scale also accepts two arguments, which are then separate factors for both
		142	horizontal and vertical dimensions. For example, this halves the image
		143	width and doubles the image height:
		144
		145	scale 0.5, 2, load "$HOME/mypic.png"
		146
		147	IF you try out these expressions, you might suffer from some sluggishness,
		148	because each time the terminal is resized, it loads the PNG image again
		149	and scales it. Scaling is usually fast (and unavoidable), but loading the
		150	image can be quite time consuming. This is where C<keep> comes in handy:
		151
		152	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		153
		154	The C<keep> operator executes all the statements inside the braces only
		155	once, or when it thinks the outcome might change. In other cases it
		156	returns the last value computed by the brace block.
		157
		158	This means that the C<load> is only executed once, which makes it much
		159	faster, but also means that more memory is being used, because the loaded
		160	image must be kept in memory at all times. In this expression, the
		161	trade-off is likely worth it.
		162
		163	But back to effects: Other effects than scaling are also readily
		164	available, for example, you can tile the image to fill the whole window,
		165	instead of resizing it:
		166
		167	tile keep { load "$HOME/mypic.png" }
		168
		169	In fact, images returned by C<load> are in C<tile> mode by default, so the
		170	C<tile> operator is kind of superfluous.
		171
		172	Another common effect is to mirror the image, so that the same edges
		173	touch:
		174
		175	mirror keep { load "$HOME/mypic.png" }
		176
		177	Another common background expression is:
		178
		179	rootalign root
		180
		181	This one first takes a snapshot of the screen background image, and then
		182	moves it to the upper left corner of the screen (as opposed to the upper
		183	left corner of the terminal window)- the result is pseudo-transparency:
		184	the image seems to be static while the window is moved around.
		185
		186	=head2 COLOUR SPECIFICATIONS
		187
		188	Whenever an operator expects a "colour", then this can be specified in one
		189	of two ways: Either as string with an X11 colour specification, such as:
		190
		191	"red" # named colour
		192	"#f00" # simple rgb
		193	"[50]red" # red with 50% alpha
		194	"TekHVC:300/50/50" # anything goes
		195
		196	OR as an array reference with one, three or four components:
		197
		198	[0.5] # 50% gray, 100% alpha
		199	[0.5, 0, 0] # dark red, no green or blur, 100% alpha
		200	[0.5, 0, 0, 0.7] # same with explicit 70% alpha
		201
		202	=head2 CACHING AND SENSITIVITY
		203
		204	Since some operations (such as C<load> and C<blur>) can take a long time,
		205	caching results can be very important for a smooth operation. Caching can
		206	also be useful to reduce memory usage, though, for example, when an image
		207	is cached by C<load>, it could be shared by multiple terminal windows
		208	running inside urxvtd.
		209
		210	=head3 C<keep { ... }> caching
		211
		212	The most important way to cache expensive operations is to use C<keep {
		213	... }>. The C<keep> operator takes a block of multiple statements enclosed
		214	by C<{}> and keeps the return value in memory.
		215
		216	An expression can be "sensitive" to various external events, such as
		217	scaling or moving the window, root background changes and timers. Simply
		218	using an expression (such as C<scale> without parameters) that depends on
		219	certain changing values (called "variables"), or using those variables
		220	directly, will make an expression sensitive to these events - for example,
		221	using C<scale> or C<TW> will make the expression sensitive to the terminal
		222	size, and thus to resizing events.
		223
		224	When such an event happens, C<keep> will automatically trigger a
		225	reevaluation of the whole expression with the new value of the expression.
		226
		227	C<keep> is most useful for expensive operations, such as C<blur>:
		228
		229	rootalign keep { blur 20, root }
		230
		231	This makes a blurred copy of the root background once, and on subsequent
		232	calls, just root-aligns it. Since C<blur> is usually quite slow and
		233	C<rootalign> is quite fast, this trades extra memory (for the cached
		234	blurred pixmap) with speed (blur only needs to be redone when root
		235	changes).
		236
		237	=head3 C<load> caching
		238
		239	The C<load> operator itself does not keep images in memory, but as long as
		240	the image is still in memory, C<load> will use the in-memory image instead
		241	of loading it freshly from disk.
		242
		243	That means that this expression:
		244
		245	keep { load "$HOME/path..." }
		246
		247	Not only caches the image in memory, other terminal instances that try to
		248	C<load> it can reuse that in-memory copy.
		249
		250	=head1 REFERENCE
		251
		252	=head2 COMMAND LINE SWITCHES
		253
		254	=over 4
		255
		256	=item --background-expr perl-expression
		257
		258	Specifies the Perl expression to evaluate.
		259
		260	=item --background-border
		261
		262	By default, the expression creates an image that fills the full window,
		263	overwriting borders and any other areas, such as the scrollbar.
		264
		265	Specifying this flag changes the behaviour, so that the image only
		266	replaces the background of the character area.
		267
		268	=item --background-interval seconds
		269
		270	Since some operations in the underlying XRender extension can effectively
		271	freeze your X-server for prolonged time, this extension enforces a minimum
		272	time between updates, which is normally about 0.1 seconds.
		273
		274	If you want to do updates more often, you can decrease this safety
		275	interval with this switch.
		276
		277	=back
		278
		279	=cut
		280
		281	our %_IMG_CACHE;
		282	our $HOME;
		283	our ($self, $frame);
18	our ($l, $t, $w, $h);	284	our ($x, $y, $w, $h);
19		285
20	# enforce at leats this time between updates	286	# enforce at least this interval between updates
21	our $MIN_INTERVAL = 1/100;	287	our $MIN_INTERVAL = 6/59.951;
22		288
23	{	289	{
24	package urxvt::bgdsl; # background language	290	package urxvt::bgdsl; # background language
25		291
26	*repeat_black = \&urxvt::RepeatNone; #TODO wtf	292	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
27	*repeat_wrap = \&urxvt::RepeatNormal;	293	sub FR_CACHE () { 1 } # cached values
28	*repeat_pad = \&urxvt::RepeatPad;	294	sub FR_AGAIN () { 2 } # what this expr is sensitive to
29	*repeat_mirror = \&urxvt::RepeatReflect;	295	sub FR_STATE () { 3 } # watchers etc.
		296
		297	use List::Util qw(min max sum shuffle);
		298
		299	=head2 PROVIDERS/GENERATORS
		300
		301	These functions provide an image, by loading it from disk, grabbing it
		302	from the root screen or by simply generating it. They are used as starting
		303	points to get an image you can play with.
		304
		305	=over 4
		306
		307	=item load $path
		308
		309	Loads the image at the given C<$path>. The image is set to plane tiling
		310	mode.
		311
		312	If the image is already in memory (e.g. because another terminal instance
		313	uses it), then the in-memory copy us returned instead.
		314
		315	=item load_uc $path
		316
		317	Load uncached - same as load, but does not cache the image, which means it
		318	is I<always> loaded from the filesystem again, even if another copy of it
		319	is in memory at the time.
		320
		321	=cut
		322
		323	sub load_uc($) {
		324	$self->new_img_from_file ($_[0])
		325	}
30		326
31	sub load($) {	327	sub load($) {
32	my ($path) = @_;	328	my ($path) = @_;
33		329
34	$new->{load}{$path} = $old->{load}{$path} \|\| $bgdsl_self->new_img_from_file ($path);	330	$_IMG_CACHE{$path} \|\| do {
		331	my $img = load_uc $path;
		332	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		333	$img
		334	}
35	}	335	}
		336
		337	=item root
		338
		339	Returns the root window pixmap, that is, hopefully, the background image
		340	of your screen.
		341
		342	This function makes your expression root sensitive, that means it will be
		343	reevaluated when the bg image changes.
		344
		345	=cut
36		346
37	sub root() {	347	sub root() {
38	$new->{rootpmap_sensitive} = 1;	348	$frame->[FR_AGAIN]{rootpmap} = 1;
39	die "root op not supported, exg, we need you";	349	$self->new_img_from_root
40	}	350	}
41		351
		352	=item solid $colour
		353
		354	=item solid $width, $height, $colour
		355
		356	Creates a new image and completely fills it with the given colour. The
		357	image is set to tiling mode.
		358
		359	If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
		360	useful for solid backgrounds or for use in filtering effects.
		361
		362	=cut
		363
		364	sub solid($;$$) {
		365	my $colour = pop;
		366
		367	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
		368	$img->fill ($colour);
		369	$img
		370	}
		371
		372	=item clone $img
		373
		374	Returns an exact copy of the image. This is useful if you want to have
		375	multiple copies of the same image to apply different effects to.
		376
		377	=cut
		378
42	# sub clone($) {	379	sub clone($) {
43	# $_[0]->clone	380	$_[0]->clone
44	# }	381	}
45		382
		383	=item merge $img ...
		384
		385	Takes any number of images and merges them together, creating a single
		386	image containing them all. The tiling mode of the first image is used as
		387	the tiling mode of the resulting image.
		388
		389	This function is called automatically when an expression returns multiple
		390	images.
		391
		392	=cut
		393
		394	sub merge(@) {
		395	return $_[0] unless $#_;
		396
		397	# rather annoyingly clumsy, but optimisation is for another time
		398
		399	my $x0 = +1e9;
		400	my $y0 = +1e9;
		401	my $x1 = -1e9;
		402	my $y1 = -1e9;
		403
		404	for (@_) {
		405	my ($x, $y, $w, $h) = $_->geometry;
		406
		407	$x0 = $x if $x0 > $x;
		408	$y0 = $y if $y0 > $y;
		409
		410	$x += $w;
		411	$y += $h;
		412
		413	$x1 = $x if $x1 < $x;
		414	$y1 = $y if $y1 < $y;
		415	}
		416
		417	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		418	$base->repeat_mode ($_[0]->repeat_mode);
		419	$base->fill ([0, 0, 0, 0]);
		420
		421	$base->draw ($_)
		422	for @_;
		423
		424	$base
		425	}
		426
		427	=head2 TILING MODES
		428
		429	The following operators modify the tiling mode of an image, that is, the
		430	way that pixels outside the image area are painted when the image is used.
		431
		432	=over 4
		433
		434	=item tile $img
		435
		436	Tiles the whole plane with the image and returns this new image - or in
		437	other words, it returns a copy of the image in plane tiling mode.
		438
		439	Example: load an image and tile it over the background, without
		440	resizing. The C<tile> call is superfluous because C<load> already defaults
		441	to tiling mode.
		442
		443	tile load "mybg.png"
		444
		445	=item mirror $img
		446
		447	Similar to tile, but reflects the image each time it uses a new copy, so
		448	that top edges always touch top edges, right edges always touch right
		449	edges and so on (with normal tiling, left edges always touch right edges
		450	and top always touch bottom edges).
		451
		452	Example: load an image and mirror it over the background, avoiding sharp
		453	edges at the image borders at the expense of mirroring the image itself
		454
		455	mirror load "mybg.png"
		456
		457	=item pad $img
		458
		459	Takes an image and modifies it so that all pixels outside the image area
		460	become transparent. This mode is most useful when you want to place an
		461	image over another image or the background colour while leaving all
		462	background pixels outside the image unchanged.
		463
		464	Example: load an image and display it in the upper left corner. The rest
		465	of the space is left "empty" (transparent or whatever your compositor does
		466	in alpha mode, else background colour).
		467
		468	pad load "mybg.png"
		469
		470	=item extend $img
		471
		472	Extends the image over the whole plane, using the closest pixel in the
		473	area outside the image. This mode is mostly useful when you use more complex
		474	filtering operations and want the pixels outside the image to have the
		475	same values as the pixels near the edge.
		476
		477	Example: just for curiosity, how does this pixel extension stuff work?
		478
		479	extend move 50, 50, load "mybg.png"
		480
		481	=cut
		482
		483	sub pad($) {
		484	my $img = $_[0]->clone;
		485	$img->repeat_mode (urxvt::RepeatNone);
		486	$img
		487	}
		488
		489	sub tile($) {
		490	my $img = $_[0]->clone;
		491	$img->repeat_mode (urxvt::RepeatNormal);
		492	$img
		493	}
		494
		495	sub mirror($) {
		496	my $img = $_[0]->clone;
		497	$img->repeat_mode (urxvt::RepeatReflect);
		498	$img
		499	}
		500
		501	sub extend($) {
		502	my $img = $_[0]->clone;
		503	$img->repeat_mode (urxvt::RepeatPad);
		504	$img
		505	}
		506
		507	=back
		508
		509	=head2 VARIABLE VALUES
		510
		511	The following functions provide variable data such as the terminal window
		512	dimensions. They are not (Perl-) variables, they just return stuff that
		513	varies. Most of them make your expression sensitive to some events, for
		514	example using C<TW> (terminal width) means your expression is evaluated
		515	again when the terminal is resized.
		516
		517	=over 4
		518
		519	=item TX
		520
		521	=item TY
		522
		523	Return the X and Y coordinates of the terminal window (the terminal
		524	window is the full window by default, and the character area only when in
		525	border-respect mode).
		526
		527	Using these functions make your expression sensitive to window moves.
		528
		529	These functions are mainly useful to align images to the root window.
		530
		531	Example: load an image and align it so it looks as if anchored to the
		532	background (that's exactly what C<rootalign> does btw.):
		533
		534	move -TX, -TY, keep { load "mybg.png" }
		535
		536	=item TW
		537
		538	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		539	terminal window is the full window by default, and the character area only
		540	when in border-respect mode).
		541
		542	Using these functions make your expression sensitive to window resizes.
		543
		544	These functions are mainly useful to scale images, or to clip images to
		545	the window size to conserve memory.
		546
		547	Example: take the screen background, clip it to the window size, blur it a
		548	bit, align it to the window position and use it as background.
		549
		550	clip move -TX, -TY, keep { blur 5, root }
		551
		552	=cut
		553
		554	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
		555	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
		556	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
		557	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
		558
		559	=item now
		560
		561	Returns the current time as (fractional) seconds since the epoch.
		562
		563	Using this expression does I<not> make your expression sensitive to time,
		564	but the next two functions do.
		565
		566	=item again $seconds
		567
		568	When this function is used the expression will be reevaluated again in
		569	C<$seconds> seconds.
		570
		571	Example: load some image and rotate it according to the time of day (as if it were
		572	the hour pointer of a clock). Update this image every minute.
		573
		574	again 60;
		575	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
		576
		577	=item counter $seconds
		578
		579	Like C<again>, but also returns an increasing counter value, starting at
		580	0, which might be useful for some simple animation effects.
		581
		582	=cut
		583
		584	sub now() { urxvt::NOW }
		585
		586	sub again($) {
		587	$frame->[FR_AGAIN]{time} = $_[0];
		588	}
		589
		590	sub counter($) {
		591	$frame->[FR_AGAIN]{time} = $_[0];
		592	$frame->[FR_STATE]{counter} + 0
		593	}
		594
		595	=back
		596
		597	=head2 SHAPE CHANGING OPERATORS
		598
		599	The following operators modify the shape, size or position of the image.
		600
		601	=over 4
		602
		603	=item clip $img
		604
		605	=item clip $width, $height, $img
		606
		607	=item clip $x, $y, $width, $height, $img
		608
		609	Clips an image to the given rectangle. If the rectangle is outside the
		610	image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is
		611	larger than the image, then the tiling mode defines how the extra pixels
		612	will be filled.
		613
		614	If C<$x> an C<$y> are missing, then C<0> is assumed for both.
		615
		616	If C<$width> and C<$height> are missing, then the window size will be
		617	assumed.
		618
		619	Example: load an image, blur it, and clip it to the window size to save
		620	memory.
		621
		622	clip keep { blur 10, load "mybg.png" }
		623
		624	=cut
		625
46	sub clip($$$$$;$) {	626	sub clip($;$$;$$) {
47	my $img = pop;	627	my $img = pop;
		628	my $h = pop \|\| TH;
		629	my $w = pop \|\| TW;
48	$img->sub_rect ($_[0], $_[1], $_[2], $_[3], $_[4])	630	$img->sub_rect ($_[0], $_[1], $w, $h)
		631	}
		632
		633	=item scale $img
		634
		635	=item scale $size_factor, $img
		636
		637	=item scale $width_factor, $height_factor, $img
		638
		639	Scales the image by the given factors in horizontal
		640	(C<$width>) and vertical (C<$height>) direction.
		641
		642	If only one factor is give, it is used for both directions.
		643
		644	If no factors are given, scales the image to the window size without
		645	keeping aspect.
		646
		647	=item resize $width, $height, $img
		648
		649	Resizes the image to exactly C<$width> times C<$height> pixels.
		650
		651	=item fit $img
		652
		653	=item fit $width, $height, $img
		654
		655	Fits the image into the given C<$width> and C<$height> without changing
		656	aspect, or the terminal size. That means it will be shrunk or grown until
		657	the whole image fits into the given area, possibly leaving borders.
		658
		659	=item cover $img
		660
		661	=item cover $width, $height, $img
		662
		663	Similar to C<fit>, but shrinks or grows until all of the area is covered
		664	by the image, so instead of potentially leaving borders, it will cut off
		665	image data that doesn't fit.
		666
		667	=cut
		668
		669	sub scale($;$;$) {
		670	my $img = pop;
		671
		672	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
		673	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
		674	: $img->scale (TW, TH)
49	}	675	}
50		676
51	sub resize($$$) {	677	sub resize($$$) {
52	my $img = pop;	678	my $img = pop;
53	$img->scale ($_[0], $_[1])	679	$img->scale ($_[0], $_[1])
54	}	680	}
55		681
56	# TODO: ugly	682	sub fit($;$$) {
		683	my $img = pop;
		684	my $w = ($_[0] \|\| TW) / $img->w;
		685	my $h = ($_[1] \|\| TH) / $img->h;
		686	scale +(min $w, $h), $img
		687	}
		688
		689	sub cover($;$$) {
		690	my $img = pop;
		691	my $w = ($_[0] \|\| TW) / $img->w;
		692	my $h = ($_[1] \|\| TH) / $img->h;
		693	scale +(max $w, $h), $img
		694	}
		695
		696	=item move $dx, $dy, $img
		697
		698	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
		699	the vertical.
		700
		701	Example: move the image right by 20 pixels and down by 30.
		702
		703	move 20, 30, ...
		704
		705	=item align $xalign, $yalign, $img
		706
		707	Aligns the image according to a factor - C<0> means the image is moved to
		708	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		709	exactly centered and C<1> means it touches the right or bottom edge.
		710
		711	Example: remove any visible border around an image, center it vertically but move
		712	it to the right hand side.
		713
		714	align 1, 0.5, pad $img
		715
		716	=item center $img
		717
		718	=item center $width, $height, $img
		719
		720	Centers the image, i.e. the center of the image is moved to the center of
		721	the terminal window (or the box specified by C<$width> and C<$height> if
		722	given).
		723
		724	Example: load an image and center it.
		725
		726	center keep { pad load "mybg.png" }
		727
		728	=item rootalign $img
		729
		730	Moves the image so that it appears glued to the screen as opposed to the
		731	window. This gives the illusion of a larger area behind the window. It is
		732	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
		733	top left of the screen.
		734
		735	Example: load a background image, put it in mirror mode and root align it.
		736
		737	rootalign keep { mirror load "mybg.png" }
		738
		739	Example: take the screen background and align it, giving the illusion of
		740	transparency as long as the window isn't in front of other windows.
		741
		742	rootalign root
		743
		744	=cut
		745
57	sub move($$;$) {	746	sub move($$;$) {
		747	my $img = pop->clone;
		748	$img->move ($_[0], $_[1]);
		749	$img
		750	}
		751
		752	sub align($;$$) {
58	my $img = pop;	753	my $img = pop;
59	$img->sub_rect (
60	$_[0], $_[1],
61	$img->w, $img->h,
62	$_[2],
63	)
64	}
65		754
		755	move $_[0] * (TW - $img->w),
		756	$_[1] * (TH - $img->h),
		757	$img
		758	}
		759
		760	sub center($;$$) {
		761	my $img = pop;
		762	my $w = $_[0] \|\| TW;
		763	my $h = $_[1] \|\| TH;
		764
		765	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		766	}
		767
		768	sub rootalign($) {
		769	move -TX, -TY, $_[0]
		770	}
		771
		772	=item rotate $center_x, $center_y, $degrees, $img
		773
		774	Rotates the image clockwise by C<$degrees> degrees, around the point at
		775	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		776
		777	Example: rotate the image by 90 degrees around it's center.
		778
		779	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		780
		781	=cut
		782
66	sub rotate($$$$$$;$) {	783	sub rotate($$$$) {
67	my $img = pop;	784	my $img = pop;
68	$img->rotate (	785	$img->rotate (
69	$_[0],	786	$_[0] * ($img->w + $img->x),
70	$_[1],	787	$_[1] * ($img->h + $img->y),
71	$_[2] * $img->w * .01,
72	$_[3] * $img->h * .01,
73	$_[4] * (3.14159265 / 180),	788	$_[2] * (3.14159265 / 180),
74	$_[5],
75	)	789	)
76	}	790	}
77		791
78	sub blur($$$) {	792	=back
79	my ($rh, $rv, $img) = @_;
80		793
81	$img->blur ($rh, $rv);	794	=head2 COLOUR MODIFICATIONS
		795
		796	The following operators change the pixels of the image.
		797
		798	=over 4
		799
		800	=item tint $color, $img
		801
		802	Tints the image in the given colour.
		803
		804	Example: tint the image red.
		805
		806	tint "red", load "rgb.png"
		807
		808	Example: the same, but specify the colour by component.
		809
		810	tint [1, 0, 0], load "rgb.png"
		811
		812	=cut
		813
		814	sub tint($$) {
		815	$_[1]->tint ($_[0])
82	}	816	}
		817
		818	=item contrast $factor, $img
		819
		820	=item contrast $r, $g, $b, $img
		821
		822	=item contrast $r, $g, $b, $a, $img
		823
		824	Adjusts the I<contrast> of an image.
		825
		826	The first form applies a single C<$factor> to red, green and blue, the
		827	second form applies separate factors to each colour channel, and the last
		828	form includes the alpha channel.
		829
		830	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		831	contrast.
		832
		833	Due to limitations in the underlying XRender extension, lowering contrast
		834	also reduces brightness, while increasing contrast currently also
		835	increases brightness.
		836
		837	=item brightness $bias, $img
		838
		839	=item brightness $r, $g, $b, $img
		840
		841	=item brightness $r, $g, $b, $a, $img
		842
		843	Adjusts the brightness of an image.
		844
		845	The first form applies a single C<$bias> to red, green and blue, the
		846	second form applies separate biases to each colour channel, and the last
		847	form includes the alpha channel.
		848
		849	Values less than 0 reduce brightness, while values larger than 0 increase
		850	it. Useful range is from -1 to 1 - the former results in a black, the
		851	latter in a white picture.
		852
		853	Due to idiosyncrasies in the underlying XRender extension, biases less
		854	than zero can be I<very> slow.
		855
		856	You can also try the experimental(!) C<muladd> operator.
		857
		858	=cut
83		859
84	sub contrast($$;$$;$) {	860	sub contrast($$;$$;$) {
85	my $img = pop;	861	my $img = pop;
86	my ($r, $g, $b, $a) = @_;	862	my ($r, $g, $b, $a) = @_;
87		863
88	($g, $b) = ($r, $r) if @_ < 4;	864	($g, $b) = ($r, $r) if @_ < 3;
89	$a = 1 if @_ < 5;	865	$a = 1 if @_ < 4;
90		866
91	$img = $img->clone;	867	$img = $img->clone;
92	$img->contrast ($r, $g, $b, $a);	868	$img->contrast ($r, $g, $b, $a);
93	$img	869	$img
94	}	870	}
95		871
96	sub brightness($$;$$;$) {	872	sub brightness($$;$$;$) {
97	my $img = pop;	873	my $img = pop;
98	my ($r, $g, $b, $a) = @_;	874	my ($r, $g, $b, $a) = @_;
99		875
100	($g, $b) = ($r, $r) if @_ < 4;	876	($g, $b) = ($r, $r) if @_ < 3;
101	$a = 1 if @_ < 5;	877	$a = 1 if @_ < 4;
102		878
103	$img = $img->clone;	879	$img = $img->clone;
104	$img->brightness ($r, $g, $b, $a);	880	$img->brightness ($r, $g, $b, $a);
105	$img	881	$img
106	}	882	}
107		883
108	sub X() { $new->{position_sensitive} = 1; $l }	884	=item muladd $mul, $add, $img # EXPERIMENTAL
109	sub Y() { $new->{position_sensitive} = 1; $t }
110	sub W() { $new->{size_sensitive} = 1; $w }
111	sub H() { $new->{size_sensitive} = 1; $h }
112		885
113	sub now() { urxvt::NOW }	886	First multipliesthe pixels by C<$mul>, then adds C<$add>. This cna be used
		887	to implement brightness and contrast at the same time, with a wider value
		888	range than contrast and brightness operators.
114		889
115	sub again($) {	890	Due to numerous bugs in XRender implementations, it can also introduce a
116	$new->{again} = $_[0];	891	number of visual artifacts.
		892
		893	Example: increase contrast by a factor of C<$c> without changing image
		894	brightness too much.
		895
		896	muladd $c, (1 - $c) * 0.5, $img
		897
		898	=cut
		899
		900	sub muladd($$$) {
		901	$_[2]->muladd ($_[0], $_[1])
		902	}
		903
		904	=item blur $radius, $img
		905
		906	=item blur $radius_horz, $radius_vert, $img
		907
		908	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
		909	can also be specified separately.
		910
		911	Blurring is often I<very> slow, at least compared or other
		912	operators. Larger blur radii are slower than smaller ones, too, so if you
		913	don't want to freeze your screen for long times, start experimenting with
		914	low values for radius (<5).
		915
		916	=cut
		917
		918	sub blur($$;$) {
		919	my $img = pop;
		920	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
		921	}
		922
		923	=back
		924
		925	=head2 OTHER STUFF
		926
		927	Anything that didn't fit any of the other categories, even after applying
		928	force and closing our eyes.
		929
		930	=over 4
		931
		932	=item keep { ... }
		933
		934	This operator takes a code block as argument, that is, one or more
		935	statements enclosed by braces.
		936
		937	The trick is that this code block is only evaluated when the outcome
		938	changes - on other calls the C<keep> simply returns the image it computed
		939	previously (yes, it should only be used with images). Or in other words,
		940	C<keep> I<caches> the result of the code block so it doesn't need to be
		941	computed again.
		942
		943	This can be extremely useful to avoid redoing slow operations - for
		944	example, if your background expression takes the root background, blurs it
		945	and then root-aligns it it would have to blur the root background on every
		946	window move or resize.
		947
		948	Another example is C<load>, which can be quite slow.
		949
		950	In fact, urxvt itself encloses the whole expression in some kind of
		951	C<keep> block so it only is reevaluated as required.
		952
		953	Putting the blur into a C<keep> block will make sure the blur is only done
		954	once, while the C<rootalign> is still done each time the window moves.
		955
		956	rootalign keep { blur 10, root }
		957
		958	This leaves the question of how to force reevaluation of the block,
		959	in case the root background changes: If expression inside the block
		960	is sensitive to some event (root background changes, window geometry
		961	changes), then it will be reevaluated automatically as needed.
		962
		963	=cut
		964
		965	sub keep(&) {
		966	my $id = $_[0]+0;
		967
		968	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		969
		970	unless ($frame->[FR_CACHE]) {
		971	$frame->[FR_CACHE] = [ $_[0]() ];
		972
		973	my $self = $self;
		974	my $frame = $frame;
		975	Scalar::Util::weaken $frame;
		976	$self->compile_frame ($frame, sub {
		977	# clear this frame cache, also for all parents
		978	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		979	undef $frame->[FR_CACHE];
		980	}
		981
		982	$self->recalculate;
		983	});
		984	};
		985
		986	# in scalar context we always return the first original result, which
		987	# is not quite how perl works.
		988	wantarray
		989	? @{ $frame->[FR_CACHE] }
		990	: $frame->[FR_CACHE][0]
		991	}
		992
		993	# sub keep_clear() {
		994	# delete $self->{frame_cache};
117	}	995	# }
118		996
119	sub counter($) {	997	=back
120	$new->{again} = $_[0];	998
121	$bgdsl_self->{counter} + 0	999	=cut
122	}	1000
123	}	1001	}
124		1002
125	sub parse_expr {	1003	sub parse_expr {
126	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	1004	my $expr = eval
		1005	"sub {\n"
		1006	. "package urxvt::bgdsl;\n"
		1007	. "#line 0 'background expression'\n"
		1008	. "$_[0]\n"
		1009	. "}";
127	die if $@;	1010	die if $@;
128	$expr	1011	$expr
129	}	1012	}
130		1013
131	# compiles a parsed expression	1014	# compiles a parsed expression
132	sub set_expr {	1015	sub set_expr {
133	my ($self, $expr) = @_;	1016	my ($self, $expr) = @_;
134		1017
		1018	$self->{root} = []; # the outermost frame
135	$self->{expr} = $expr;	1019	$self->{expr} = $expr;
136	$self->recalculate;	1020	$self->recalculate;
137	}	1021	}
138		1022
		1023	# takes a hash of sensitivity indicators and installs watchers
		1024	sub compile_frame {
		1025	my ($self, $frame, $cb) = @_;
		1026
		1027	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		1028	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		1029
		1030	# don't keep stuff alive
		1031	Scalar::Util::weaken $state;
		1032
		1033	if ($again->{nested}) {
		1034	$state->{nested} = 1;
		1035	} else {
		1036	delete $state->{nested};
		1037	}
		1038
		1039	if (my $interval = $again->{time}) {
		1040	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		1041	if $state->{time}[0] != $interval;
		1042
		1043	# callback might have changed, although we could just rule that out
		1044	$state->{time}[1]->cb (sub {
		1045	++$state->{counter};
		1046	$cb->();
		1047	});
		1048	} else {
		1049	delete $state->{time};
		1050	}
		1051
		1052	if ($again->{position}) {
		1053	$state->{position} = $self->on (position_change => $cb);
		1054	} else {
		1055	delete $state->{position};
		1056	}
		1057
		1058	if ($again->{size}) {
		1059	$state->{size} = $self->on (size_change => $cb);
		1060	} else {
		1061	delete $state->{size};
		1062	}
		1063
		1064	if ($again->{rootpmap}) {
		1065	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		1066	} else {
		1067	delete $state->{rootpmap};
		1068	}
		1069	}
		1070
139	# evaluate the current bg expression	1071	# evaluate the current bg expression
140	sub recalculate {	1072	sub recalculate {
141	my ($self) = @_;	1073	my ($arg_self) = @_;
142		1074
143	# rate limit evaluation	1075	# rate limit evaluation
144		1076
145	if ($self->{next_refresh} > urxvt::NOW) {	1077	if ($arg_self->{next_refresh} > urxvt::NOW) {
146	$self->{next_refresh_timer} = urxvt::timer->new->after ($self->{next_refresh} - urxvt::NOW)->cb (sub {	1078	$arg_self->{next_refresh_timer} = urxvt::timer->new->after ($arg_self->{next_refresh} - urxvt::NOW)->cb (sub {
147	$self->recalculate;	1079	$arg_self->recalculate;
148	});	1080	});
149	return;	1081	return;
150	}	1082	}
151		1083
152	$self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1084	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
153		1085
154	# set environment to evaluate user expression	1086	# set environment to evaluate user expression
155		1087
156	local $bgdsl_self = $self;	1088	local $self = $arg_self;
157		1089	local $HOME = $ENV{HOME};
158	local $old = $self->{state};	1090	local $frame = $self->{root};
159	local $new = my $state = $self->{state} = {};
160		1091
161	($l, $t, $w, $h) =	1092	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
162	$self->get_geometry;
163		1093
164	# evaluate user expression	1094	# evaluate user expression
165		1095
166	my $img = eval { $self->{expr}->() };	1096	my @img = eval { $self->{expr}->() };
167	warn $@ if $@;#d#	1097	die $@ if $@;
		1098	die "background-expr did not return anything.\n" unless @img;
		1099	die "background-expr: expected image(s), got something else.\n"
		1100	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
		1101
		1102	my $img = urxvt::bgdsl::merge @img;
		1103
		1104	$frame->[FR_AGAIN]{size} = 1
		1105	if $img->repeat_mode != urxvt::RepeatNormal;
168		1106
169	# if the expression is sensitive to external events, prepare reevaluation then	1107	# if the expression is sensitive to external events, prepare reevaluation then
170		1108	$self->compile_frame ($frame, sub { $arg_self->recalculate });
171	my $repeat;
172
173	if (my $again = $state->{again}) {
174	$repeat = 1;
175	$state->{timer} = $again == $old->{again}
176	? $old->{timer}
177	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
178	++$self->{counter};
179	$self->recalculate
180	});
181	}
182
183	if (delete $state->{position_sensitive}) {
184	$repeat = 1;
185	$self->enable (position_change => sub { $_[0]->recalculate });
186	} else {
187	$self->disable ("position_change");
188	}
189
190	if (delete $state->{size_sensitive}) {
191	$repeat = 1;
192	$self->enable (size_change => sub { $_[0]->recalculate });
193	} else {
194	$self->disable ("size_change");
195	}
196
197	if (delete $state->{rootpmap_sensitive}) {
198	$repeat = 1;
199	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
200	} else {
201	$self->disable ("rootpmap_change");
202	}
203		1109
204	# clear stuff we no longer need	1110	# clear stuff we no longer need
205		1111
206	%$old = ();	1112	# unless (%{ $frame->[FR_STATE] }) {
207
208	unless ($repeat) {
209	delete $self->{state};	1113	# delete $self->{state};
210	delete $self->{expr};	1114	# delete $self->{expr};
211	}	1115	# }
212		1116
213	# prepare and set background pixmap	1117	# set background pixmap
214		1118
215	$img = $img->sub_rect (0, 0, $w, $h)
216	if $img->w != $w \|\| $img->h != $h;
217
218	$self->set_background ($img);	1119	$self->set_background ($img, $self->{border});
219	$self->scr_recolour (0);	1120	$self->scr_recolour (0);
220	$self->want_refresh;	1121	$self->want_refresh;
221	}	1122	}
222		1123
223	sub on_start {	1124	sub on_start {
224	my ($self) = @_;	1125	my ($self) = @_;
225		1126
		1127	my $expr = $self->x_resource ("%.expr")
		1128	or return;
		1129
		1130	$self->has_render
		1131	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1132
226	$self->set_expr (parse_expr $EXPR);	1133	$self->set_expr (parse_expr $expr);
		1134	$self->{border} = $self->x_resource_boolean ("%.border");
		1135
		1136	$MIN_INTERVAL = $self->x_resource ("%.interval");
227		1137
228	()	1138	()
229	}	1139	}
230		1140

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.13 by root, Tue Jun 5 19:32:29 2012 UTC vs. Revision 1.75 by root, Fri Aug 10 20:07:11 2012 UTC

Diff Legend

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.13 by root, Tue Jun 5 19:32:29 2012 UTC vs.
Revision 1.75 by root, Fri Aug 10 20:07:11 2012 UTC