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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.26 by root, Thu Jun 7 11:34:09 2012 UTC vs.
Revision 1.86 by sf-exg, Fri Oct 4 17:09:57 2013 UTC

1	#! perl	1	#! perl
2		2
3	#:META:X_RESOURCE:%.expr:string:background expression	3	#:META:X_RESOURCE:%.expr:string:background expression
4	#:META:X_RESOURCE:%.enable:boolean:some boolean	4	#:META:X_RESOURCE:%.border:boolean:respect the terminal border
5	#:META:X_RESOURCE:%.extra.:value:extra config	5	#:META:X_RESOURCE:%.interval:seconds:minimum time between updates
6		6
7	our $EXPR = 'move W * 0.1, -H * 0.1, resize W * 0.5, H * 0.5, repeat_none load "MagnoliaAlpha.png"';	7	=head1 NAME
8	#$EXPR = '
9	# rotate W, H, 50, 50, counter 1/59.95, repeat_mirror,
10	# clip X, Y, W, H, repeat_mirror,
11	# load "/root/pix/das_fette_schwein.jpg"
12	#';
13	#$EXPR = 'solid "red"';
14	#$EXPR = 'blur root, 10, 10'
15	#$EXPR = 'blur move (root, -x, -y), 5, 5'
16	#resize load "/root/pix/das_fette_schwein.jpg", w, h
17		8
18	use Safe;	9	background - manage terminal background
19		10
20	our ($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, $frame);
21	our ($l, $t, $w, $h);	284	our ($x, $y, $w, $h, $focus);
22		285
23	# enforce at least this interval between updates	286	# enforce at least this interval between updates
24	our $MIN_INTERVAL = 1/100;	287	our $MIN_INTERVAL = 6/59.951;
25		288
26	{	289	{
27	package urxvt::bgdsl; # background language	290	package urxvt::bgdsl; # background language
28		291
29	# *repeat_empty = \&urxvt::RepeatNone;	292	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
30	# *repeat_tile = \&urxvt::RepeatNormal;	293	sub FR_CACHE () { 1 } # cached values
31	# *repeat_pad = \&urxvt::RepeatPad;	294	sub FR_AGAIN () { 2 } # what this expr is sensitive to
32	# *repeat_mirror = \&urxvt::RepeatReflect;	295	sub FR_STATE () { 3 } # watchers etc.
		296
		297	use List::Util qw(min max sum shuffle);
33		298
34	=head2 PROVIDERS/GENERATORS	299	=head2 PROVIDERS/GENERATORS
35		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
36	=over 4	305	=over 4
37		306
38	=item load $path	307	=item load $path
39		308
		309	Loads the image at the given C<$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 is returned instead.
		314
		315	=item load_uc $path
		316
		317	Load uncached - same as load, but does not cache the image, which means it
		318	is I<always> loaded from the filesystem again, even if another copy of it
		319	is in memory at the time.
		320
40	=cut	321	=cut
		322
		323	sub load_uc($) {
		324	$self->new_img_from_file ($_[0])
		325	}
41		326
42	sub load($) {	327	sub load($) {
43	my ($path) = @_;	328	my ($path) = @_;
44		329
45	$new->{load}{$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	}
46	}	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
47		346
48	sub root() {	347	sub root() {
49	$new->{rootpmap_sensitive} = 1;	348	$frame->[FR_AGAIN]{rootpmap} = 1;
50	die "root op not supported, exg, we need you";	349	$self->new_img_from_root
51	}	350	}
		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<$height> are omitted, it creates a 1x1 image, which is
		360	useful for solid backgrounds or for use in filtering effects.
		361
		362	=cut
52		363
53	sub solid($;$$) {	364	sub solid($;$$) {
		365	my $colour = pop;
		366
54	my $img = $bgdsl_self->new_img (urxvt::PictStandardARGB32, $_[1] \|\| 1, $_[2] \|\| 1);	367	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
55	$img->fill ($_[0]);	368	$img->fill ($colour);
56	$img	369	$img
57	}	370	}
58		371
		372	=item clone $img
		373
		374	Returns an exact copy of the image. This is useful if you want to have
		375	multiple copies of the same image to apply different effects to.
		376
		377	=cut
		378
		379	sub clone($) {
		380	$_[0]->clone
		381	}
		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
59	=back	427	=back
60		428
61	=head2 VARIABLES	429	=head2 TILING MODES
		430
		431	The following operators modify the tiling mode of an image, that is, the
		432	way that pixels outside the image area are painted when the image is used.
62		433
63	=over 4	434	=over 4
64		435
65	=cut	436	=item tile $img
66		437
67	sub X() { $new->{position_sensitive} = 1; $l }	438	Tiles the whole plane with the image and returns this new image - or in
68	sub Y() { $new->{position_sensitive} = 1; $t }	439	other words, it returns a copy of the image in plane tiling mode.
69	sub W() { $new->{size_sensitive} = 1; $w }
70	sub H() { $new->{size_sensitive} = 1; $h }
71		440
72	sub now() { urxvt::NOW }	441	Example: load an image and tile it over the background, without
		442	resizing. The C<tile> call is superfluous because C<load> already defaults
		443	to tiling mode.
73		444
		445	tile load "mybg.png"
		446
		447	=item mirror $img
		448
		449	Similar to tile, but reflects the image each time it uses a new copy, so
		450	that top edges always touch top edges, right edges always touch right
		451	edges and so on (with normal tiling, left edges always touch right edges
		452	and top always touch bottom edges).
		453
		454	Example: load an image and mirror it over the background, avoiding sharp
		455	edges at the image borders at the expense of mirroring the image itself
		456
		457	mirror load "mybg.png"
		458
		459	=item pad $img
		460
		461	Takes an image and modifies it so that all pixels outside the image area
		462	become transparent. This mode is most useful when you want to place an
		463	image over another image or the background colour while leaving all
		464	background pixels outside the image unchanged.
		465
		466	Example: load an image and display it in the upper left corner. The rest
		467	of the space is left "empty" (transparent or whatever your compositor does
		468	in alpha mode, else background colour).
		469
		470	pad load "mybg.png"
		471
		472	=item extend $img
		473
		474	Extends the image over the whole plane, using the closest pixel in the
		475	area outside the image. This mode is mostly useful when you use more complex
		476	filtering operations and want the pixels outside the image to have the
		477	same values as the pixels near the edge.
		478
		479	Example: just for curiosity, how does this pixel extension stuff work?
		480
		481	extend move 50, 50, load "mybg.png"
		482
		483	=cut
		484
74	sub again($) {	485	sub pad($) {
75	$new->{again} = $_[0];
76	}
77
78	sub counter($) {
79	$new->{again} = $_[0];
80	$bgdsl_self->{counter} + 0
81	}
82
83	=back
84
85	=head2 OPERATORS
86
87	=over 4
88
89	=cut
90
91	# sub clone($) {
92	# $_[0]->clone
93	# }
94
95	sub repeat_none($) {
96	my $img = $_[0]->clone;	486	my $img = $_[0]->clone;
97	$img->repeat_mode (urxvt::RepeatNone);	487	$img->repeat_mode (urxvt::RepeatNone);
98	$img	488	$img
99	}	489	}
100		490
		491	sub tile($) {
		492	my $img = $_[0]->clone;
		493	$img->repeat_mode (urxvt::RepeatNormal);
		494	$img
		495	}
		496
		497	sub mirror($) {
		498	my $img = $_[0]->clone;
		499	$img->repeat_mode (urxvt::RepeatReflect);
		500	$img
		501	}
		502
		503	sub extend($) {
		504	my $img = $_[0]->clone;
		505	$img->repeat_mode (urxvt::RepeatPad);
		506	$img
		507	}
		508
		509	=back
		510
		511	=head2 VARIABLE VALUES
		512
		513	The following functions provide variable data such as the terminal window
		514	dimensions. They are not (Perl-) variables, they just return stuff that
		515	varies. Most of them make your expression sensitive to some events, for
		516	example using C<TW> (terminal width) means your expression is evaluated
		517	again when the terminal is resized.
		518
		519	=over 4
		520
		521	=item TX
		522
		523	=item TY
		524
		525	Return the X and Y coordinates of the terminal window (the terminal
		526	window is the full window by default, and the character area only when in
		527	border-respect mode).
		528
		529	Using these functions makes your expression sensitive to window moves.
		530
		531	These functions are mainly useful to align images to the root window.
		532
		533	Example: load an image and align it so it looks as if anchored to the
		534	background (that's exactly what C<rootalign> does btw.):
		535
		536	move -TX, -TY, keep { load "mybg.png" }
		537
		538	=item TW
		539
		540	=item TH
		541
		542	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		543	terminal window is the full window by default, and the character area only
		544	when in border-respect mode).
		545
		546	Using these functions makes your expression sensitive to window resizes.
		547
		548	These functions are mainly useful to scale images, or to clip images to
		549	the window size to conserve memory.
		550
		551	Example: take the screen background, clip it to the window size, blur it a
		552	bit, align it to the window position and use it as background.
		553
		554	clip move -TX, -TY, keep { blur 5, root }
		555
		556	=item FOCUS
		557
		558	Returns a boolean indicating whether the terminal window has keyboard
		559	focus, in which case it returns true.
		560
		561	Using this function makes your expression sensitive to focus changes.
		562
		563	A common use case is to fade the background image when the terminal loses
		564	focus, often together with the C<-fade> command line option. In fact,
		565	there is a special function for just that use case: C<focus_fade>.
		566
		567	Example: use two entirely different background images, depending on
		568	whether the window has focus.
		569
		570	FOCUS ? keep { load "has_focus.jpg" } : keep { load "no_focus.jpg" }
		571
		572	=cut
		573
		574	sub TX () { $frame->[FR_AGAIN]{position} = 1; $x }
		575	sub TY () { $frame->[FR_AGAIN]{position} = 1; $y }
		576	sub TW () { $frame->[FR_AGAIN]{size} = 1; $w }
		577	sub TH () { $frame->[FR_AGAIN]{size} = 1; $h }
		578	sub FOCUS() { $frame->[FR_AGAIN]{focus} = 1; $focus }
		579
		580	=item now
		581
		582	Returns the current time as (fractional) seconds since the epoch.
		583
		584	Using this expression does I<not> make your expression sensitive to time,
		585	but the next two functions do.
		586
		587	=item again $seconds
		588
		589	When this function is used the expression will be reevaluated again in
		590	C<$seconds> seconds.
		591
		592	Example: load some image and rotate it according to the time of day (as if it were
		593	the hour pointer of a clock). Update this image every minute.
		594
		595	again 60;
		596	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
		597
		598	=item counter $seconds
		599
		600	Like C<again>, but also returns an increasing counter value, starting at
		601	0, which might be useful for some simple animation effects.
		602
		603	=cut
		604
		605	sub now() { urxvt::NOW }
		606
		607	sub again($) {
		608	$frame->[FR_AGAIN]{time} = $_[0];
		609	}
		610
		611	sub counter($) {
		612	$frame->[FR_AGAIN]{time} = $_[0];
		613	$frame->[FR_STATE]{counter} + 0
		614	}
		615
		616	=back
		617
		618	=head2 SHAPE CHANGING OPERATORS
		619
		620	The following operators modify the shape, size or position of the image.
		621
		622	=over 4
		623
		624	=item clip $img
		625
		626	=item clip $width, $height, $img
		627
		628	=item clip $x, $y, $width, $height, $img
		629
		630	Clips an image to the given rectangle. If the rectangle is outside the
		631	image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is
		632	larger than the image, then the tiling mode defines how the extra pixels
		633	will be filled.
		634
		635	If C<$x> and C<$y> are missing, then C<0> is assumed for both.
		636
		637	If C<$width> and C<$height> are missing, then the window size will be
		638	assumed.
		639
		640	Example: load an image, blur it, and clip it to the window size to save
		641	memory.
		642
		643	clip keep { blur 10, load "mybg.png" }
		644
		645	=cut
		646
101	sub clip($;$$;$$) {	647	sub clip($;$$;$$) {
102	my $img = pop;	648	my $img = pop;
103	my $h = pop \|\| H;	649	my $h = pop \|\| TH;
104	my $w = pop \|\| W;	650	my $w = pop \|\| TW;
105	$img->sub_rect ($_[0], $_[1], $w, $h)	651	$img->sub_rect ($_[0], $_[1], $w, $h)
		652	}
		653
		654	=item scale $img
		655
		656	=item scale $size_factor, $img
		657
		658	=item scale $width_factor, $height_factor, $img
		659
		660	Scales the image by the given factors in horizontal
		661	(C<$width>) and vertical (C<$height>) direction.
		662
		663	If only one factor is given, it is used for both directions.
		664
		665	If no factors are given, scales the image to the window size without
		666	keeping aspect.
		667
		668	=item resize $width, $height, $img
		669
		670	Resizes the image to exactly C<$width> times C<$height> pixels.
		671
		672	=item fit $img
		673
		674	=item fit $width, $height, $img
		675
		676	Fits the image into the given C<$width> and C<$height> without changing
		677	aspect, or the terminal size. That means it will be shrunk or grown until
		678	the whole image fits into the given area, possibly leaving borders.
		679
		680	=item cover $img
		681
		682	=item cover $width, $height, $img
		683
		684	Similar to C<fit>, but shrinks or grows until all of the area is covered
		685	by the image, so instead of potentially leaving borders, it will cut off
		686	image data that doesn't fit.
		687
		688	=cut
		689
		690	sub scale($;$;$) {
		691	my $img = pop;
		692
		693	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
		694	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
		695	: $img->scale (TW, TH)
106	}	696	}
107		697
108	sub resize($$$) {	698	sub resize($$$) {
109	my $img = pop;	699	my $img = pop;
110	$img->scale ($_[0], $_[1])	700	$img->scale ($_[0], $_[1])
111	}	701	}
112		702
113	# TODO: ugly	703	sub fit($;$$) {
		704	my $img = pop;
		705	my $w = ($_[0] \|\| TW) / $img->w;
		706	my $h = ($_[1] \|\| TH) / $img->h;
		707	scale +(min $w, $h), $img
		708	}
		709
		710	sub cover($;$$) {
		711	my $img = pop;
		712	my $w = ($_[0] \|\| TW) / $img->w;
		713	my $h = ($_[1] \|\| TH) / $img->h;
		714	scale +(max $w, $h), $img
		715	}
		716
		717	=item move $dx, $dy, $img
		718
		719	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
		720	the vertical.
		721
		722	Example: move the image right by 20 pixels and down by 30.
		723
		724	move 20, 30, ...
		725
		726	=item align $xalign, $yalign, $img
		727
		728	Aligns the image according to a factor - C<0> means the image is moved to
		729	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		730	exactly centered and C<1> means it touches the right or bottom edge.
		731
		732	Example: remove any visible border around an image, center it vertically but move
		733	it to the right hand side.
		734
		735	align 1, 0.5, pad $img
		736
		737	=item center $img
		738
		739	=item center $width, $height, $img
		740
		741	Centers the image, i.e. the center of the image is moved to the center of
		742	the terminal window (or the box specified by C<$width> and C<$height> if
		743	given).
		744
		745	Example: load an image and center it.
		746
		747	center keep { pad load "mybg.png" }
		748
		749	=item rootalign $img
		750
		751	Moves the image so that it appears glued to the screen as opposed to the
		752	window. This gives the illusion of a larger area behind the window. It is
		753	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
		754	top left of the screen.
		755
		756	Example: load a background image, put it in mirror mode and root align it.
		757
		758	rootalign keep { mirror load "mybg.png" }
		759
		760	Example: take the screen background and align it, giving the illusion of
		761	transparency as long as the window isn't in front of other windows.
		762
		763	rootalign root
		764
		765	=cut
		766
114	sub move($$;$) {	767	sub move($$;$) {
115	my $img = pop->clone;	768	my $img = pop->clone;
116	$img->move ($_[0], $_[1]);	769	$img->move ($_[0], $_[1]);
117	$img	770	$img
		771	}
		772
		773	sub align($;$$) {
118	# my $img = pop;	774	my $img = pop;
119	# $img->sub_rect (
120	# $_[0], $_[1],
121	# $img->w, $img->h,
122	# $_[2],
123	# )
124	}
125		775
		776	move $_[0] * (TW - $img->w),
		777	$_[1] * (TH - $img->h),
		778	$img
		779	}
		780
		781	sub center($;$$) {
		782	my $img = pop;
		783	my $w = $_[0] \|\| TW;
		784	my $h = $_[1] \|\| TH;
		785
		786	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		787	}
		788
		789	sub rootalign($) {
		790	move -TX, -TY, $_[0]
		791	}
		792
		793	=item rotate $center_x, $center_y, $degrees, $img
		794
		795	Rotates the image clockwise by C<$degrees> degrees, around the point at
		796	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		797
		798	Example: rotate the image by 90 degrees around its center.
		799
		800	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		801
		802	=cut
		803
126	sub rotate($$$$$$) {	804	sub rotate($$$$) {
127	my $img = pop;	805	my $img = pop;
128	$img->rotate (	806	$img->rotate (
129	$_[0],	807	$_[0] * ($img->w + $img->x),
130	$_[1],	808	$_[1] * ($img->h + $img->y),
131	$_[2] * $img->w * .01,
132	$_[3] * $img->h * .01,
133	$_[4] * (3.14159265 / 180),	809	$_[2] * (3.14159265 / 180),
134	)	810	)
135	}	811	}
136		812
137	sub blur($$$) {	813	=back
138	my ($rh, $rv, $img) = @_;
139		814
140	$img->blur ($rh, $rv);	815	=head2 COLOUR MODIFICATIONS
		816
		817	The following operators change the pixels of the image.
		818
		819	=over 4
		820
		821	=item tint $color, $img
		822
		823	Tints the image in the given colour.
		824
		825	Example: tint the image red.
		826
		827	tint "red", load "rgb.png"
		828
		829	Example: the same, but specify the colour by component.
		830
		831	tint [1, 0, 0], load "rgb.png"
		832
		833	=cut
		834
		835	sub tint($$) {
		836	$_[1]->tint ($_[0])
141	}	837	}
		838
		839	=item shade $factor, $img
		840
		841	Shade the image by the given factor.
		842
		843	=cut
		844
		845	sub shade($$) {
		846	$_[1]->shade ($_[0])
		847	}
		848
		849	=item contrast $factor, $img
		850
		851	=item contrast $r, $g, $b, $img
		852
		853	=item contrast $r, $g, $b, $a, $img
		854
		855	Adjusts the I<contrast> of an image.
		856
		857	The first form applies a single C<$factor> to red, green and blue, the
		858	second form applies separate factors to each colour channel, and the last
		859	form includes the alpha channel.
		860
		861	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		862	contrast.
		863
		864	Due to limitations in the underlying XRender extension, lowering contrast
		865	also reduces brightness, while increasing contrast currently also
		866	increases brightness.
		867
		868	=item brightness $bias, $img
		869
		870	=item brightness $r, $g, $b, $img
		871
		872	=item brightness $r, $g, $b, $a, $img
		873
		874	Adjusts the brightness of an image.
		875
		876	The first form applies a single C<$bias> to red, green and blue, the
		877	second form applies separate biases to each colour channel, and the last
		878	form includes the alpha channel.
		879
		880	Values less than 0 reduce brightness, while values larger than 0 increase
		881	it. Useful range is from -1 to 1 - the former results in a black, the
		882	latter in a white picture.
		883
		884	Due to idiosyncrasies in the underlying XRender extension, biases less
		885	than zero can be I<very> slow.
		886
		887	You can also try the experimental(!) C<muladd> operator.
		888
		889	=cut
142		890
143	sub contrast($$;$$;$) {	891	sub contrast($$;$$;$) {
144	my $img = pop;	892	my $img = pop;
145	my ($r, $g, $b, $a) = @_;	893	my ($r, $g, $b, $a) = @_;
146		894
147	($g, $b) = ($r, $r) if @_ < 4;	895	($g, $b) = ($r, $r) if @_ < 3;
148	$a = 1 if @_ < 5;	896	$a = 1 if @_ < 4;
149		897
150	$img = $img->clone;	898	$img = $img->clone;
151	$img->contrast ($r, $g, $b, $a);	899	$img->contrast ($r, $g, $b, $a);
152	$img	900	$img
153	}	901	}
154		902
155	sub brightness($$;$$;$) {	903	sub brightness($$;$$;$) {
156	my $img = pop;	904	my $img = pop;
157	my ($r, $g, $b, $a) = @_;	905	my ($r, $g, $b, $a) = @_;
158		906
159	($g, $b) = ($r, $r) if @_ < 4;	907	($g, $b) = ($r, $r) if @_ < 3;
160	$a = 1 if @_ < 5;	908	$a = 1 if @_ < 4;
161		909
162	$img = $img->clone;	910	$img = $img->clone;
163	$img->brightness ($r, $g, $b, $a);	911	$img->brightness ($r, $g, $b, $a);
164	$img	912	$img
165	}	913	}
166		914
		915	=item muladd $mul, $add, $img # EXPERIMENTAL
		916
		917	First multiplies the pixels by C<$mul>, then adds C<$add>. This can be used
		918	to implement brightness and contrast at the same time, with a wider value
		919	range than contrast and brightness operators.
		920
		921	Due to numerous bugs in XRender implementations, it can also introduce a
		922	number of visual artifacts.
		923
		924	Example: increase contrast by a factor of C<$c> without changing image
		925	brightness too much.
		926
		927	muladd $c, (1 - $c) * 0.5, $img
		928
		929	=cut
		930
		931	sub muladd($$$) {
		932	$_[2]->muladd ($_[0], $_[1])
		933	}
		934
		935	=item blur $radius, $img
		936
		937	=item blur $radius_horz, $radius_vert, $img
		938
		939	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
		940	can also be specified separately.
		941
		942	Blurring is often I<very> slow, at least compared or other
		943	operators. Larger blur radii are slower than smaller ones, too, so if you
		944	don't want to freeze your screen for long times, start experimenting with
		945	low values for radius (<5).
		946
		947	=cut
		948
		949	sub blur($$;$) {
		950	my $img = pop;
		951	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
		952	}
		953
		954	=item focus_fade $img
		955
		956	=item focus_fade $factor, $img
		957
		958	=item focus_fade $factor, $color, $img
		959
		960	Fades the image by the given factor (and colour) when focus is lost (the
		961	same as the C<-fade>/C<-fadecolor> command line options, which also supply
		962	the default values for C<factor> and C<$color>. Unlike with C<-fade>, the
		963	C<$factor> is the real value, not a percentage value (that is, 0..1, not
		964	0..100).
		965
		966	Example: do the right thing when focus fading is requested.
		967
		968	focus_fade load "mybg.jpg";
		969
		970	=cut
		971
		972	sub focus_fade($;$$) {
		973	my $img = pop;
		974
		975	return $img
		976	if FOCUS;
		977
		978	my $fade = @_ >= 1 ? $_[0] : defined $self->resource ("fade") ? $self->resource ("fade") * 0.01 : 0;
		979	my $color = @_ >= 2 ? $_[1] : $self->resource ("color+" . urxvt::Color_fade);
		980
		981	$img = $img->tint ($color) if $color ne "rgb:00/00/00";
		982	$img = $img->muladd (1 - $fade, 0) if $fade;
		983
		984	$img
		985	}
		986
167	=back	987	=back
168		988
		989	=head2 OTHER STUFF
		990
		991	Anything that didn't fit any of the other categories, even after applying
		992	force and closing our eyes.
		993
		994	=over 4
		995
		996	=item keep { ... }
		997
		998	This operator takes a code block as argument, that is, one or more
		999	statements enclosed by braces.
		1000
		1001	The trick is that this code block is only evaluated when the outcome
		1002	changes - on other calls the C<keep> simply returns the image it computed
		1003	previously (yes, it should only be used with images). Or in other words,
		1004	C<keep> I<caches> the result of the code block so it doesn't need to be
		1005	computed again.
		1006
		1007	This can be extremely useful to avoid redoing slow operations - for
		1008	example, if your background expression takes the root background, blurs it
		1009	and then root-aligns it it would have to blur the root background on every
		1010	window move or resize.
		1011
		1012	Another example is C<load>, which can be quite slow.
		1013
		1014	In fact, urxvt itself encloses the whole expression in some kind of
		1015	C<keep> block so it only is reevaluated as required.
		1016
		1017	Putting the blur into a C<keep> block will make sure the blur is only done
		1018	once, while the C<rootalign> is still done each time the window moves.
		1019
		1020	rootalign keep { blur 10, root }
		1021
		1022	This leaves the question of how to force reevaluation of the block,
		1023	in case the root background changes: If expression inside the block
		1024	is sensitive to some event (root background changes, window geometry
		1025	changes), then it will be reevaluated automatically as needed.
		1026
		1027	=cut
		1028
		1029	sub keep(&) {
		1030	my $id = $_[0]+0;
		1031
		1032	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		1033
		1034	unless ($frame->[FR_CACHE]) {
		1035	$frame->[FR_CACHE] = [ $_[0]() ];
		1036
		1037	my $self = $self;
		1038	my $frame = $frame;
		1039	Scalar::Util::weaken $frame;
		1040	$self->compile_frame ($frame, sub {
		1041	# clear this frame cache, also for all parents
		1042	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		1043	undef $frame->[FR_CACHE];
		1044	}
		1045
		1046	$self->recalculate;
		1047	});
		1048	};
		1049
		1050	# in scalar context we always return the first original result, which
		1051	# is not quite how perl works.
		1052	wantarray
		1053	? @{ $frame->[FR_CACHE] }
		1054	: $frame->[FR_CACHE][0]
		1055	}
		1056
		1057	# sub keep_clear() {
		1058	# delete $self->{frame_cache};
		1059	# }
		1060
		1061	=back
		1062
169	=cut	1063	=cut
170		1064
171	}	1065	}
172		1066
173	sub parse_expr {	1067	sub parse_expr {
174	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	1068	my $expr = eval
		1069	"sub {\n"
		1070	. "package urxvt::bgdsl;\n"
		1071	. "#line 0 'background expression'\n"
		1072	. "$_[0]\n"
		1073	. "}";
175	die if $@;	1074	die if $@;
176	$expr	1075	$expr
177	}	1076	}
178		1077
179	# compiles a parsed expression	1078	# compiles a parsed expression
180	sub set_expr {	1079	sub set_expr {
181	my ($self, $expr) = @_;	1080	my ($self, $expr) = @_;
182		1081
		1082	$self->{root} = []; # the outermost frame
183	$self->{expr} = $expr;	1083	$self->{expr} = $expr;
184	$self->recalculate;	1084	$self->recalculate;
185	}	1085	}
186		1086
		1087	# takes a hash of sensitivity indicators and installs watchers
		1088	sub compile_frame {
		1089	my ($self, $frame, $cb) = @_;
		1090
		1091	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		1092	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		1093
		1094	# don't keep stuff alive
		1095	Scalar::Util::weaken $state;
		1096
		1097	if ($again->{nested}) {
		1098	$state->{nested} = 1;
		1099	} else {
		1100	delete $state->{nested};
		1101	}
		1102
		1103	if (my $interval = $again->{time}) {
		1104	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		1105	if $state->{time}[0] != $interval;
		1106
		1107	# callback might have changed, although we could just rule that out
		1108	$state->{time}[1]->cb (sub {
		1109	++$state->{counter};
		1110	$cb->();
		1111	});
		1112	} else {
		1113	delete $state->{time};
		1114	}
		1115
		1116	if ($again->{position}) {
		1117	$state->{position} = $self->on (position_change => $cb);
		1118	} else {
		1119	delete $state->{position};
		1120	}
		1121
		1122	if ($again->{size}) {
		1123	$state->{size} = $self->on (size_change => $cb);
		1124	} else {
		1125	delete $state->{size};
		1126	}
		1127
		1128	if ($again->{rootpmap}) {
		1129	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		1130	} else {
		1131	delete $state->{rootpmap};
		1132	}
		1133
		1134	if ($again->{focus}) {
		1135	$state->{focus} = $self->on (focus_in => $cb, focus_out => $cb);
		1136	} else {
		1137	delete $state->{focus};
		1138	}
		1139	}
		1140
187	# evaluate the current bg expression	1141	# evaluate the current bg expression
188	sub recalculate {	1142	sub recalculate {
189	my ($self) = @_;	1143	my ($arg_self) = @_;
190		1144
191	# rate limit evaluation	1145	# rate limit evaluation
192		1146
193	if ($self->{next_refresh} > urxvt::NOW) {	1147	if ($arg_self->{next_refresh} > urxvt::NOW) {
194	$self->{next_refresh_timer} = urxvt::timer->new->after ($self->{next_refresh} - urxvt::NOW)->cb (sub {	1148	$arg_self->{next_refresh_timer} = urxvt::timer->new->after ($arg_self->{next_refresh} - urxvt::NOW)->cb (sub {
195	$self->recalculate;	1149	$arg_self->recalculate;
196	});	1150	});
197	return;	1151	return;
198	}	1152	}
199		1153
200	$self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1154	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
201		1155
202	# set environment to evaluate user expression	1156	# set environment to evaluate user expression
203		1157
204	local $bgdsl_self = $self;	1158	local $self = $arg_self;
205		1159	local $HOME = $ENV{HOME};
206	local $old = $self->{state};	1160	local $frame = $self->{root};
207	local $new = my $state = $self->{state} = {};
208		1161
209	($l, $t, $w, $h) =	1162	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
210	$self->get_geometry;	1163	$focus = $self->focus;
211
212	warn "$l,$t,$w,$h\n";#d#
213		1164
214	# evaluate user expression	1165	# evaluate user expression
215		1166
216	my $img = eval { $self->{expr}->() };	1167	my @img = eval { $self->{expr}->() };
217	warn $@ if $@;#d#	1168	die $@ if $@;
		1169	die "background-expr did not return anything.\n" unless @img;
		1170	die "background-expr: expected image(s), got something else.\n"
218	die if !UNIVERSAL::isa $img, "urxvt::img";	1171	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
		1172
		1173	my $img = urxvt::bgdsl::merge @img;
		1174
		1175	$frame->[FR_AGAIN]{size} = 1
		1176	if $img->repeat_mode != urxvt::RepeatNormal;
219		1177
220	# if the expression is sensitive to external events, prepare reevaluation then	1178	# if the expression is sensitive to external events, prepare reevaluation then
221		1179	$self->compile_frame ($frame, sub { $arg_self->recalculate });
222	my $repeat;
223
224	if (my $again = $state->{again}) {
225	$repeat = 1;
226	$state->{timer} = $again == $old->{again}
227	? $old->{timer}
228	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
229	++$self->{counter};
230	$self->recalculate
231	});
232	}
233
234	if (delete $state->{position_sensitive}) {
235	$repeat = 1;
236	$self->enable (position_change => sub { $_[0]->recalculate });
237	} else {
238	$self->disable ("position_change");
239	}
240
241	if (delete $state->{size_sensitive}) {
242	$repeat = 1;
243	$self->enable (size_change => sub { $_[0]->recalculate });
244	} else {
245	$self->disable ("size_change");
246	}
247
248	if (delete $state->{rootpmap_sensitive}) {
249	$repeat = 1;
250	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
251	} else {
252	$self->disable ("rootpmap_change");
253	}
254		1180
255	# clear stuff we no longer need	1181	# clear stuff we no longer need
256		1182
257	%$old = ();	1183	# unless (%{ $frame->[FR_STATE] }) {
258
259	unless ($repeat) {
260	delete $self->{state};	1184	# delete $self->{state};
261	delete $self->{expr};	1185	# delete $self->{expr};
262	}	1186	# }
263		1187
264	# prepare and set background pixmap	1188	# set background pixmap
265		1189
266	$img = $img->sub_rect (0, 0, $w, $h)
267	if $img->w != $w \|\| $img->h != $h;
268
269	$self->set_background ($img);	1190	$self->set_background ($img, $self->{border});
270	$self->scr_recolour (0);	1191	$self->scr_recolour (0);
271	$self->want_refresh;	1192	$self->want_refresh;
272	}	1193	}
273		1194
274	sub on_start {	1195	sub on_start {
275	my ($self) = @_;	1196	my ($self) = @_;
276		1197
		1198	my $expr = $self->x_resource ("%.expr")
		1199	or return;
		1200
		1201	$self->has_render
		1202	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1203
277	$self->set_expr (parse_expr $EXPR);	1204	$self->set_expr (parse_expr $expr);
		1205	$self->{border} = $self->x_resource_boolean ("%.border");
		1206
		1207	$MIN_INTERVAL = $self->x_resource ("%.interval");
278		1208
279	()	1209	()
280	}	1210	}
281		1211

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.26 by root, Thu Jun 7 11:34:09 2012 UTC vs. Revision 1.86 by sf-exg, Fri Oct 4 17:09:57 2013 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.26 by root, Thu Jun 7 11:34:09 2012 UTC vs.
Revision 1.86 by sf-exg, Fri Oct 4 17:09:57 2013 UTC