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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.30 by root, Thu Jun 7 13:22:06 2012 UTC vs.
Revision 1.69 by root, Mon Jul 2 01:32:26 2012 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 $EXPR;	7	=head1 NAME
8	#$EXPR = 'move W * 0.1, -H * 0.1, resize W * 0.5, H * 0.5, repeat_none load "opensource.png"';
9	$EXPR = 'move -TX, -TY, load "argb.png"';
10	#$EXPR = '
11	# rotate W, H, 50, 50, counter 1/59.95, repeat_mirror,
12	# clip X, Y, W, H, repeat_mirror,
13	# load "/root/pix/das_fette_schwein.jpg"
14	#';
15	#$EXPR = 'solid "red"';
16	#$EXPR = 'blur root, 10, 10'
17	#$EXPR = 'blur move (root, -x, -y), 5, 5'
18	#resize load "/root/pix/das_fette_schwein.jpg", w, h
19		8
20	use Safe;	9	background - manage terminal background
21		10
22	our ($bgdsl_self, $old, $new);	11	=head1 SYNOPSIS
		12
		13	urxvt --background-expr 'background expression'
		14	--background-border
		15	--background-interval seconds
		16
		17	=head1 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 keep { load "/path/to/mybg.png" }'
		32
		33	Or specified as a X resource:
		34
		35	URxvt.background-expr: scale keep { 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 keep { load "$HOME/mybg.png"
		59	}> scales the image to the window size, so it relies on the window size
		60	and will 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	scale keep {
		70	again 3600;
		71	if (localtime now)[6]) {
		72	return load "$HOME/weekday.png";
		73	} else {
		74	return load "$HOME/sunday.png";
		75	}
		76	}
		77
		78	This inner expression is evaluated once per hour (and whenever the
		79	temrinal window is resized). It sets F<sunday.png> as background on
		80	Sundays, and F<weekday.png> on all other days.
		81
		82	Fortunately, we expect that most expressions will be much simpler, with
		83	little Perl knowledge needed.
		84
		85	Basically, you always start with a function that "generates" an image
		86	object, such as C<load>, which loads an image from disk, or C<root>, which
		87	returns the root window background image:
		88
		89	load "$HOME/mypic.png"
		90
		91	The path is usually specified as a quoted string (the exact rules can be
		92	found in the L<perlop> manpage). The F<$HOME> at the beginning of the
		93	string is expanded to the home directory.
		94
		95	Then you prepend one or more modifiers or filtering expressions, such as
		96	C<scale>:
		97
		98	scale load "$HOME/mypic.png"
		99
		100	Just like a mathematical expression with functions, you should read these
		101	expressions from right to left, as the C<load> is evaluated first, and
		102	its result becomes the argument to the C<scale> function.
		103
		104	Many operators also allow some parameters preceding the input image
		105	that modify its behaviour. For example, C<scale> without any additional
		106	arguments scales the image to size of the terminal window. If you specify
		107	an additional argument, it uses it as a scale factor (multiply by 100 to
		108	get a percentage):
		109
		110	scale 2, load "$HOME/mypic.png"
		111
		112	This enlarges the image by a factor of 2 (200%). As you can see, C<scale>
		113	has now two arguments, the C<200> and the C<load> expression, while
		114	C<load> only has one argument. Arguments are separated from each other by
		115	commas.
		116
		117	Scale also accepts two arguments, which are then separate factors for both
		118	horizontal and vertical dimensions. For example, this halves the image
		119	width and doubles the image height:
		120
		121	scale 0.5, 2, load "$HOME/mypic.png"
		122
		123	IF you try out these expressions, you might suffer from some sluggishness,
		124	because each time the terminal is resized, it loads the PNG image agin
		125	and scales it. Scaling is usually fast (and unavoidable), but loading the
		126	image can be quite time consuming. This is where C<keep> comes in handy:
		127
		128	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		129
		130	The C<keep> operator executes all the statements inside the braces only
		131	once, or when it thinks the outcome might change. In other cases it
		132	returns the last value computed by the brace block.
		133
		134	This means that the C<load> is only executed once, which makes it much
		135	faster, but also means that more memory is being used, because the loaded
		136	image must be kept in memory at all times. In this expression, the
		137	trade-off is likely worth it.
		138
		139	But back to effects: Other effects than scaling are also readily
		140	available, for example, you can tile the image to fill the whole window,
		141	instead of resizing it:
		142
		143	tile keep { load "$HOME/mypic.png" }
		144
		145	In fact, images returned by C<load> are in C<tile> mode by default, so the
		146	C<tile> operator is kind of superfluous.
		147
		148	Another common effect is to mirror the image, so that the same edges
		149	touch:
		150
		151	mirror keep { load "$HOME/mypic.png" }
		152
		153	Another common background expression is:
		154
		155	rootalign root
		156
		157	This one first takes a snapshot of the screen background image, and then
		158	moves it to the upper left corner of the screen (as opposed to the upper
		159	left corner of the terminal window)- the result is pseudo-transparency:
		160	the image seems to be static while the window is moved around.
		161
		162	=head2 CACHING AND SENSITIVITY
		163
		164	Since some operations (such as C<load> and C<blur>) can take a long time,
		165	caching results can be very important for a smooth operation. Caching can
		166	also be useful to reduce memory usage, though, for example, when an image
		167	is cached by C<load>, it could be shared by multiple terminal windows
		168	running inside urxvtd.
		169
		170	=head3 C<keep { ... }> caching
		171
		172	The most important way to cache expensive operations is to use C<keep {
		173	... }>. The C<keep> operator takes a block of multiple statements enclosed
		174	by C<{}> and keeps the return value in memory.
		175
		176	An expression can be "sensitive" to various external events, such as
		177	scaling or moving the window, root background changes and timers. Simply
		178	using an expression (such as C<scale> without parameters) that depends on
		179	certain changing values (called "variables"), or using those variables
		180	directly, will make an expression sensitive to these events - for example,
		181	using C<scale> or C<TW> will make the expression sensitive to the terminal
		182	size, and thus to resizing events.
		183
		184	When such an event happens, C<keep> will automatically trigger a
		185	reevaluation of the whole expression with the new value of the expression.
		186
		187	C<keep> is most useful for expensive operations, such as C<blur>:
		188
		189	rootalign keep { blur 20, root }
		190
		191	This makes a blurred copy of the root background once, and on subsequent
		192	calls, just root-aligns it. Since C<blur> is usually quite slow and
		193	C<rootalign> is quite fast, this trades extra memory (for the cached
		194	blurred pixmap) with speed (blur only needs to be redone when root
		195	changes).
		196
		197	=head3 C<load> caching
		198
		199	The C<load> operator itself does not keep images in memory, but as long as
		200	the image is still in memory, C<load> will use the in-memory image instead
		201	of loading it freshly from disk.
		202
		203	That means that this expression:
		204
		205	keep { load "$HOME/path..." }
		206
		207	Not only caches the image in memory, other terminal instances that try to
		208	C<load> it can reuse that in-memory copy.
		209
		210	=head1 REFERENCE
		211
		212	=head2 COMMAND LINE SWITCHES
		213
		214	=over 4
		215
		216	=item --background-expr perl-expression
		217
		218	Specifies the Perl expression to evaluate.
		219
		220	=item --background-border
		221
		222	By default, the expression creates an image that fills the full window,
		223	overwriting borders and any other areas, such as the scrollbar.
		224
		225	Specifying this flag changes the behaviour, so that the image only
		226	replaces the background of the character area.
		227
		228	=item --background-interval seconds
		229
		230	Since some operations in the underlying XRender extension can effectively
		231	freeze your X-server for prolonged time, this extension enforces a minimum
		232	time between updates, which is normally about 0.1 seconds.
		233
		234	If you want to do updates more often, you can decrease this safety
		235	interval with this switch.
		236
		237	=back
		238
		239	=cut
		240
		241	our %_IMG_CACHE;
		242	our $HOME;
		243	our ($self, $frame);
23	our ($x, $y, $w, $h);	244	our ($x, $y, $w, $h);
24		245
25	# enforce at least this interval between updates	246	# enforce at least this interval between updates
26	our $MIN_INTERVAL = 1/100;	247	our $MIN_INTERVAL = 6/59.951;
27		248
28	{	249	{
29	package urxvt::bgdsl; # background language	250	package urxvt::bgdsl; # background language
30		251
		252	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
		253	sub FR_CACHE () { 1 } # cached values
		254	sub FR_AGAIN () { 2 } # what this expr is sensitive to
		255	sub FR_STATE () { 3 } # watchers etc.
		256
		257	use List::Util qw(min max sum shuffle);
		258
31	=head2 PROVIDERS/GENERATORS	259	=head2 PROVIDERS/GENERATORS
		260
		261	These functions provide an image, by loading it from disk, grabbing it
		262	from the root screen or by simply generating it. They are used as starting
		263	points to get an image you can play with.
32		264
33	=over 4	265	=over 4
34		266
35	=item load $path	267	=item load $path
36		268
37	Loads the image at the given C<$path>. The image is set to plane tiling	269	Loads the image at the given C<$path>. The image is set to plane tiling
38	mode.	270	mode.
39		271
		272	If the image is already in memory (e.g. because another terminal instance
		273	uses it), then the in-memory copy us returned instead.
40		274
		275	=item load_uc $path
		276
		277	Load uncached - same as load, but does not cache the image, which means it
		278	is I<always> loaded from the filesystem again.
41		279
42	=cut	280	=cut
43		281
44	sub load($) {	282	sub load($) {
45	my ($path) = @_;	283	my ($path) = @_;
46		284
47	$new->{load}{$path} = $old->{load}{$path} \|\| $bgdsl_self->new_img_from_file ($path);	285	$_IMG_CACHE{$path} \|\| do {
		286	my $img = $self->new_img_from_file ($path);
		287	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		288	$img
		289	}
48	}	290	}
		291
		292	=item root
		293
		294	Returns the root window pixmap, that is, hopefully, the background image
		295	of your screen.
		296
		297	This function makes your expression root sensitive, that means it will be
		298	reevaluated when the bg image changes.
		299
		300	=cut
49		301
50	sub root() {	302	sub root() {
51	$new->{rootpmap_sensitive} = 1;	303	$frame->[FR_AGAIN]{rootpmap} = 1;
52	die "root op not supported, exg, we need you";	304	$self->new_img_from_root
53	}	305	}
		306
		307	=item solid $colour
		308
		309	=item solid $width, $height, $colour
		310
		311	Creates a new image and completely fills it with the given colour. The
		312	image is set to tiling mode.
		313
		314	If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
		315	useful for solid backgrounds or for use in filtering effects.
		316
		317	=cut
54		318
55	sub solid($;$$) {	319	sub solid($;$$) {
		320	my $colour = pop;
		321
56	my $img = $bgdsl_self->new_img (urxvt::PictStandardARGB32, $_[1] \|\| 1, $_[2] \|\| 1);	322	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
57	$img->fill ($_[0]);	323	$img->fill ($colour);
58	$img	324	$img
59	}	325	}
60		326
61	=back	327	=item clone $img
62		328
63	=head2 VARIABLES	329	Returns an exact copy of the image. This is useful if you want to have
		330	multiple copies of the same image to apply different effects to.
64		331
65	=over 4
66
67	=cut	332	=cut
68		333
69	sub TX() { $new->{position_sensitive} = 1; $x }
70	sub TY() { $new->{position_sensitive} = 1; $y }
71	sub TW() { $new->{size_sensitive} = 1; $w }
72	sub TH() { $new->{size_sensitive} = 1; $h }
73
74	sub now() { urxvt::NOW }
75
76	sub again($) {
77	$new->{again} = $_[0];
78	}
79
80	sub counter($) {	334	sub clone($) {
81	$new->{again} = $_[0];	335	$_[0]->clone
82	$bgdsl_self->{counter} + 0
83	}	336	}
84		337
85	=back	338	=item merge $img ...
		339
		340	Takes any number of images and merges them together, creating a single
		341	image containing them all. The tiling mode of the first image is used as
		342	the tiling mode of the resulting image.
		343
		344	This function is called automatically when an expression returns multiple
		345	images.
		346
		347	=cut
		348
		349	sub merge(@) {
		350	return $_[0] unless $#_;
		351
		352	# rather annoyingly clumsy, but optimisation is for another time
		353
		354	my $x0 = +1e9;
		355	my $y0 = +1e9;
		356	my $x1 = -1e9;
		357	my $y1 = -1e9;
		358
		359	for (@_) {
		360	my ($x, $y, $w, $h) = $_->geometry;
		361
		362	$x0 = $x if $x0 > $x;
		363	$y0 = $y if $y0 > $y;
		364
		365	$x += $w;
		366	$y += $h;
		367
		368	$x1 = $x if $x1 < $x;
		369	$y1 = $y if $y1 < $y;
		370	}
		371
		372	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		373	$base->repeat_mode ($_[0]->repeat_mode);
		374	$base->fill ([0, 0, 0, 0]);
		375
		376	$base->draw ($_)
		377	for @_;
		378
		379	$base
		380	}
86		381
87	=head2 TILING MODES	382	=head2 TILING MODES
88		383
89	The following operators modify the tiling mode of an image, that is, the	384	The following operators modify the tiling mode of an image, that is, the
90	way that pixels outside the image area are painted when the image is used.	385	way that pixels outside the image area are painted when the image is used.
93		388
94	=item tile $img	389	=item tile $img
95		390
96	Tiles the whole plane with the image and returns this new image - or in	391	Tiles the whole plane with the image and returns this new image - or in
97	other words, it returns a copy of the image in plane tiling mode.	392	other words, it returns a copy of the image in plane tiling mode.
		393
		394	Example: load an image and tile it over the background, without
		395	resizing. The C<tile> call is superfluous because C<load> already defaults
		396	to tiling mode.
		397
		398	tile load "mybg.png"
98		399
99	=item mirror $img	400	=item mirror $img
100		401
101	Similar to tile, but reflects the image each time it uses a new copy, so	402	Similar to tile, but reflects the image each time it uses a new copy, so
102	that top edges always touch top edges, right edges always touch right	403	that top edges always touch top edges, right edges always touch right
103	edges and so on (with normal tiling, left edges always touch right edges	404	edges and so on (with normal tiling, left edges always touch right edges
104	and top always touch bottom edges).	405	and top always touch bottom edges).
105		406
		407	Example: load an image and mirror it over the background, avoiding sharp
		408	edges at the image borders at the expense of mirroring the image itself
		409
		410	mirror load "mybg.png"
		411
106	=item pad $img	412	=item pad $img
107		413
108	Takes an image and modifies it so that all pixels outside the image area	414	Takes an image and modifies it so that all pixels outside the image area
109	become transparent. This mode is most useful when you want to place an	415	become transparent. This mode is most useful when you want to place an
110	image over another image or the background colour while leaving all	416	image over another image or the background colour while leaving all
111	background pixels outside the image unchanged.	417	background pixels outside the image unchanged.
112		418
		419	Example: load an image and display it in the upper left corner. The rest
		420	of the space is left "empty" (transparent or whatever your compositor does
		421	in alpha mode, else background colour).
		422
		423	pad load "mybg.png"
		424
113	=item extend $img	425	=item extend $img
114		426
115	Extends the image over the whole plane, using the closest pixel in the	427	Extends the image over the whole plane, using the closest pixel in the
116	area outside the image. This mode is mostly useful when you more complex	428	area outside the image. This mode is mostly useful when you use more complex
117	filtering operations and want the pixels outside the image to have the	429	filtering operations and want the pixels outside the image to have the
118	same values as the pixels near the edge.	430	same values as the pixels near the edge.
		431
		432	Example: just for curiosity, how does this pixel extension stuff work?
		433
		434	extend move 50, 50, load "mybg.png"
119		435
120	=cut	436	=cut
121		437
122	sub pad($) {	438	sub pad($) {
123	my $img = $_[0]->clone;	439	my $img = $_[0]->clone;
…		…
143	$img	459	$img
144	}	460	}
145		461
146	=back	462	=back
147		463
148	=head2 PIXEL OPERATORS	464	=head2 VARIABLE VALUES
149		465
150	The following operators modify the image pixels in various ways.	466	The following functions provide variable data such as the terminal window
		467	dimensions. They are not (Perl-) variables, they just return stuff that
		468	varies. Most of them make your expression sensitive to some events, for
		469	example using C<TW> (terminal width) means your expression is evaluated
		470	again when the terminal is resized.
151		471
152	=over 4	472	=over 4
153		473
154	=item clone $img	474	=item TX
155		475
156	Returns an exact copy of the image.	476	=item TY
157		477
158	=cut	478	Return the X and Y coordinates of the terminal window (the terminal
		479	window is the full window by default, and the character area only when in
		480	border-respect mode).
159		481
		482	Using these functions make your expression sensitive to window moves.
		483
		484	These functions are mainly useful to align images to the root window.
		485
		486	Example: load an image and align it so it looks as if anchored to the
		487	background (that's exactly what C<rootalign> does btw.):
		488
		489	move -TX, -TY, keep { load "mybg.png" }
		490
		491	=item TW
		492
		493	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		494	terminal window is the full window by default, and the character area only
		495	when in border-respect mode).
		496
		497	Using these functions make your expression sensitive to window resizes.
		498
		499	These functions are mainly useful to scale images, or to clip images to
		500	the window size to conserve memory.
		501
		502	Example: take the screen background, clip it to the window size, blur it a
		503	bit, align it to the window position and use it as background.
		504
		505	clip move -TX, -TY, keep { blur 5, root }
		506
		507	=cut
		508
		509	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
		510	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
		511	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
		512	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
		513
		514	=item now
		515
		516	Returns the current time as (fractional) seconds since the epoch.
		517
		518	Using this expression does I<not> make your expression sensitive to time,
		519	but the next two functions do.
		520
		521	=item again $seconds
		522
		523	When this function is used the expression will be reevaluated again in
		524	C<$seconds> seconds.
		525
		526	Example: load some image and rotate it according to the time of day (as if it were
		527	the hour pointer of a clock). Update this image every minute.
		528
		529	again 60;
		530	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
		531
		532	=item counter $seconds
		533
		534	Like C<again>, but also returns an increasing counter value, starting at
		535	0, which might be useful for some simple animation effects.
		536
		537	=cut
		538
		539	sub now() { urxvt::NOW }
		540
		541	sub again($) {
		542	$frame->[FR_AGAIN]{time} = $_[0];
		543	}
		544
160	sub clone($) {	545	sub counter($) {
161	$_[0]->clone	546	$frame->[FR_AGAIN]{time} = $_[0];
		547	$frame->[FR_STATE]{counter} + 0
162	}	548	}
		549
		550	=back
		551
		552	=head2 SHAPE CHANGING OPERATORS
		553
		554	The following operators modify the shape, size or position of the image.
		555
		556	=over 4
163		557
164	=item clip $img	558	=item clip $img
165		559
166	=item clip $width, $height, $img	560	=item clip $width, $height, $img
167		561
…		…
178	assumed.	572	assumed.
179		573
180	Example: load an image, blur it, and clip it to the window size to save	574	Example: load an image, blur it, and clip it to the window size to save
181	memory.	575	memory.
182		576
183	clip blur 10, load "mybg.png"	577	clip keep { blur 10, load "mybg.png" }
184		578
185	=cut	579	=cut
186		580
187	sub clip($;$$;$$) {	581	sub clip($;$$;$$) {
188	my $img = pop;	582	my $img = pop;
…		…
191	$img->sub_rect ($_[0], $_[1], $w, $h)	585	$img->sub_rect ($_[0], $_[1], $w, $h)
192	}	586	}
193		587
194	=item scale $img	588	=item scale $img
195		589
196	=item scale $size_percent, $img	590	=item scale $size_factor, $img
197		591
198	=item scale $width_percent, $height_percent, $img	592	=item scale $width_factor, $height_factor, $img
199		593
200	Scales the image by the given percentages in horizontal	594	Scales the image by the given factors in horizontal
201	(C<$width_percent>) and vertical (C<$height_percent>) direction.	595	(C<$width>) and vertical (C<$height>) direction.
202		596
203	If only one percentage is give, it is used for both directions.	597	If only one factor is give, it is used for both directions.
204		598
205	If no percentages are given, scales the image to the window size without	599	If no factors are given, scales the image to the window size without
206	keeping aspect.	600	keeping aspect.
207		601
208	=item resize $width, $height, $img	602	=item resize $width, $height, $img
209		603
210	Resizes the image to exactly C<$width> times C<$height> pixels.	604	Resizes the image to exactly C<$width> times C<$height> pixels.
211		605
212	=cut	606	=item fit $img
213		607
214	#TODO: maximise, maximise_fill?	608	=item fit $width, $height, $img
215		609
		610	Fits the image into the given C<$width> and C<$height> without changing
		611	aspect, or the terminal size. That means it will be shrunk or grown until
		612	the whole image fits into the given area, possibly leaving borders.
		613
		614	=item cover $img
		615
		616	=item cover $width, $height, $img
		617
		618	Similar to C<fit>, but shrinks or grows until all of the area is covered
		619	by the image, so instead of potentially leaving borders, it will cut off
		620	image data that doesn't fit.
		621
		622	=cut
		623
216	sub scale($$$) {	624	sub scale($;$;$) {
217	my $img = pop;	625	my $img = pop;
218		626
219	@_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01)	627	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
220	: @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01)	628	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
221	: $img->scale (TW, TH)	629	: $img->scale (TW, TH)
222	}	630	}
223		631
224	sub resize($$$) {	632	sub resize($$$) {
225	my $img = pop;	633	my $img = pop;
226	$img->scale ($_[0], $_[1])	634	$img->scale ($_[0], $_[1])
227	}	635	}
		636
		637	sub fit($;$$) {
		638	my $img = pop;
		639	my $w = ($_[0] \|\| TW) / $img->w;
		640	my $h = ($_[1] \|\| TH) / $img->h;
		641	scale +(min $w, $h), $img
		642	}
		643
		644	sub cover($;$$) {
		645	my $img = pop;
		646	my $w = ($_[0] \|\| TW) / $img->w;
		647	my $h = ($_[1] \|\| TH) / $img->h;
		648	scale +(max $w, $h), $img
		649	}
		650
		651	=item move $dx, $dy, $img
		652
		653	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
		654	the vertical.
		655
		656	Example: move the image right by 20 pixels and down by 30.
		657
		658	move 20, 30, ...
		659
		660	=item align $xalign, $yalign, $img
		661
		662	Aligns the image according to a factor - C<0> means the image is moved to
		663	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		664	exactly centered and C<1> means it touches the right or bottom edge.
		665
		666	Example: remove any visible border around an image, center it vertically but move
		667	it to the right hand side.
		668
		669	align 1, 0.5, pad $img
		670
		671	=item center $img
		672
		673	=item center $width, $height, $img
		674
		675	Centers the image, i.e. the center of the image is moved to the center of
		676	the terminal window (or the box specified by C<$width> and C<$height> if
		677	given).
		678
		679	Example: load an image and center it.
		680
		681	center keep { pad load "mybg.png" }
		682
		683	=item rootalign $img
		684
		685	Moves the image so that it appears glued to the screen as opposed to the
		686	window. This gives the illusion of a larger area behind the window. It is
		687	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
		688	top left of the screen.
		689
		690	Example: load a background image, put it in mirror mode and root align it.
		691
		692	rootalign keep { mirror load "mybg.png" }
		693
		694	Example: take the screen background and align it, giving the illusion of
		695	transparency as long as the window isn't in front of other windows.
		696
		697	rootalign root
		698
		699	=cut
228		700
229	sub move($$;$) {	701	sub move($$;$) {
230	my $img = pop->clone;	702	my $img = pop->clone;
231	$img->move ($_[0], $_[1]);	703	$img->move ($_[0], $_[1]);
232	$img	704	$img
233	}	705	}
234		706
		707	sub align($;$$) {
		708	my $img = pop;
		709
		710	move $_[0] * (TW - $img->w),
		711	$_[1] * (TH - $img->h),
		712	$img
		713	}
		714
		715	sub center($;$$) {
		716	my $img = pop;
		717	my $w = $_[0] \|\| TW;
		718	my $h = $_[1] \|\| TH;
		719
		720	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		721	}
		722
		723	sub rootalign($) {
		724	move -TX, -TY, $_[0]
		725	}
		726
		727	=item rotate $center_x, $center_y, $degrees, $img
		728
		729	Rotates the image clockwise by C<$degrees> degrees, around the point at
		730	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		731
		732	Example: rotate the image by 90 degrees around it's center.
		733
		734	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		735
		736	=cut
		737
235	sub rotate($$$$$$) {	738	sub rotate($$$$) {
236	my $img = pop;	739	my $img = pop;
237	$img->rotate (	740	$img->rotate (
238	$_[0],	741	$_[0] * ($img->w + $img->x),
239	$_[1],	742	$_[1] * ($img->h + $img->y),
240	$_[2] * $img->w * .01,
241	$_[3] * $img->h * .01,
242	$_[4] * (3.14159265 / 180),	743	$_[2] * (3.14159265 / 180),
243	)	744	)
244	}	745	}
		746
		747	=back
		748
		749	=head2 COLOUR MODIFICATIONS
		750
		751	The following operators change the pixels of the image.
		752
		753	=over 4
		754
		755	=item contrast $factor, $img
		756
		757	=item contrast $r, $g, $b, $img
		758
		759	=item contrast $r, $g, $b, $a, $img
		760
		761	Adjusts the I<contrast> of an image.
		762
		763	The first form applies a single C<$factor> to red, green and blue, the
		764	second form applies separate factors to each colour channel, and the last
		765	form includes the alpha channel.
		766
		767	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		768	contrast.
		769
		770	Due to limitations in the underlying XRender extension, lowering contrast
		771	also reduces brightness, while increasing contrast currently also
		772	increases brightness.
		773
		774	=item brightness $bias, $img
		775
		776	=item brightness $r, $g, $b, $img
		777
		778	=item brightness $r, $g, $b, $a, $img
		779
		780	Adjusts the brightness of an image.
		781
		782	The first form applies a single C<$bias> to red, green and blue, the
		783	second form applies separate biases to each colour channel, and the last
		784	form includes the alpha channel.
		785
		786	Values less than 0 reduce brightness, while values larger than 0 increase
		787	it. Useful range is from -1 to 1 - the former results in a black, the
		788	latter in a white picture.
		789
		790	Due to idiosyncrasies in the underlying XRender extension, biases less
		791	than zero can be I<very> slow.
		792
		793	=cut
		794
		795	sub contrast($$;$$;$) {
		796	my $img = pop;
		797	my ($r, $g, $b, $a) = @_;
		798
		799	($g, $b) = ($r, $r) if @_ < 3;
		800	$a = 1 if @_ < 4;
		801
		802	$img = $img->clone;
		803	$img->contrast ($r, $g, $b, $a);
		804	$img
		805	}
		806
		807	sub brightness($$;$$;$) {
		808	my $img = pop;
		809	my ($r, $g, $b, $a) = @_;
		810
		811	($g, $b) = ($r, $r) if @_ < 3;
		812	$a = 1 if @_ < 4;
		813
		814	$img = $img->clone;
		815	$img->brightness ($r, $g, $b, $a);
		816	$img
		817	}
		818
		819	=item blur $radius, $img
		820
		821	=item blur $radius_horz, $radius_vert, $img
		822
		823	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
		824	can also be specified separately.
		825
		826	Blurring is often I<very> slow, at least compared or other
		827	operators. Larger blur radii are slower than smaller ones, too, so if you
		828	don't want to freeze your screen for long times, start experimenting with
		829	low values for radius (<5).
		830
		831	=cut
245		832
246	sub blur($$;$) {	833	sub blur($$;$) {
247	my $img = pop;	834	my $img = pop;
248	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	835	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
249	}	836	}
250		837
251	sub contrast($$;$$;$) {
252	my $img = pop;
253	my ($r, $g, $b, $a) = @_;
254
255	($g, $b) = ($r, $r) if @_ < 4;
256	$a = 1 if @_ < 5;
257
258	$img = $img->clone;
259	$img->contrast ($r, $g, $b, $a);
260	$img
261	}
262
263	sub brightness($$;$$;$) {
264	my $img = pop;
265	my ($r, $g, $b, $a) = @_;
266
267	($g, $b) = ($r, $r) if @_ < 4;
268	$a = 1 if @_ < 5;
269
270	$img = $img->clone;
271	$img->brightness ($r, $g, $b, $a);
272	$img
273	}
274
275	=back	838	=back
276		839
		840	=head2 OTHER STUFF
		841
		842	Anything that didn't fit any of the other categories, even after applying
		843	force and closing our eyes.
		844
		845	=over 4
		846
		847	=item keep { ... }
		848
		849	This operator takes a code block as argument, that is, one or more
		850	statements enclosed by braces.
		851
		852	The trick is that this code block is only evaluated when the outcome
		853	changes - on other calls the C<keep> simply returns the image it computed
		854	previously (yes, it should only be used with images). Or in other words,
		855	C<keep> I<caches> the result of the code block so it doesn't need to be
		856	computed again.
		857
		858	This can be extremely useful to avoid redoing slow operations - for
		859	example, if your background expression takes the root background, blurs it
		860	and then root-aligns it it would have to blur the root background on every
		861	window move or resize.
		862
		863	Another example is C<load>, which can be quite slow.
		864
		865	In fact, urxvt itself encloses the whole expression in some kind of
		866	C<keep> block so it only is reevaluated as required.
		867
		868	Putting the blur into a C<keep> block will make sure the blur is only done
		869	once, while the C<rootalign> is still done each time the window moves.
		870
		871	rootlign keep { blur 10, root }
		872
		873	This leaves the question of how to force reevaluation of the block,
		874	in case the root background changes: If expression inside the block
		875	is sensitive to some event (root background changes, window geometry
		876	changes), then it will be reevaluated automatically as needed.
		877
		878	=cut
		879
		880	sub keep(&) {
		881	my $id = $_[0]+0;
		882
		883	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		884
		885	unless ($frame->[FR_CACHE]) {
		886	$frame->[FR_CACHE] = [ $_[0]() ];
		887
		888	my $self = $self;
		889	my $frame = $frame;
		890	Scalar::Util::weaken $frame;
		891	$self->compile_frame ($frame, sub {
		892	# clear this frame cache, also for all parents
		893	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		894	undef $frame->[FR_CACHE];
		895	}
		896
		897	$self->recalculate;
		898	});
		899	};
		900
		901	# in scalar context we always return the first original result, which
		902	# is not quite how perl works.
		903	wantarray
		904	? @{ $frame->[FR_CACHE] }
		905	: $frame->[FR_CACHE][0]
		906	}
		907
		908	# sub keep_clear() {
		909	# delete $self->{frame_cache};
		910	# }
		911
		912	=back
		913
277	=cut	914	=cut
278		915
279	}	916	}
280		917
281	sub parse_expr {	918	sub parse_expr {
282	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	919	my $expr = eval
		920	"sub {\n"
		921	. "package urxvt::bgdsl;\n"
		922	. "#line 0 'background expression'\n"
		923	. "$_[0]\n"
		924	. "}";
283	die if $@;	925	die if $@;
284	$expr	926	$expr
285	}	927	}
286		928
287	# compiles a parsed expression	929	# compiles a parsed expression
288	sub set_expr {	930	sub set_expr {
289	my ($self, $expr) = @_;	931	my ($self, $expr) = @_;
290		932
		933	$self->{root} = [];
291	$self->{expr} = $expr;	934	$self->{expr} = $expr;
292	$self->recalculate;	935	$self->recalculate;
293	}	936	}
294		937
		938	# takes a hash of sensitivity indicators and installs watchers
		939	sub compile_frame {
		940	my ($self, $frame, $cb) = @_;
		941
		942	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		943	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		944
		945	# don't keep stuff alive
		946	Scalar::Util::weaken $state;
		947
		948	if ($again->{nested}) {
		949	$state->{nested} = 1;
		950	} else {
		951	delete $state->{nested};
		952	}
		953
		954	if (my $interval = $again->{time}) {
		955	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		956	if $state->{time}[0] != $interval;
		957
		958	# callback might have changed, although we could just rule that out
		959	$state->{time}[1]->cb (sub {
		960	++$state->{counter};
		961	$cb->();
		962	});
		963	} else {
		964	delete $state->{time};
		965	}
		966
		967	if ($again->{position}) {
		968	$state->{position} = $self->on (position_change => $cb);
		969	} else {
		970	delete $state->{position};
		971	}
		972
		973	if ($again->{size}) {
		974	$state->{size} = $self->on (size_change => $cb);
		975	} else {
		976	delete $state->{size};
		977	}
		978
		979	if ($again->{rootpmap}) {
		980	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		981	} else {
		982	delete $state->{rootpmap};
		983	}
		984	}
		985
295	# evaluate the current bg expression	986	# evaluate the current bg expression
296	sub recalculate {	987	sub recalculate {
297	my ($self) = @_;	988	my ($arg_self) = @_;
298		989
299	# rate limit evaluation	990	# rate limit evaluation
300		991
301	if ($self->{next_refresh} > urxvt::NOW) {	992	if ($arg_self->{next_refresh} > urxvt::NOW) {
302	$self->{next_refresh_timer} = urxvt::timer->new->after ($self->{next_refresh} - urxvt::NOW)->cb (sub {	993	$arg_self->{next_refresh_timer} = urxvt::timer->new->after ($arg_self->{next_refresh} - urxvt::NOW)->cb (sub {
303	$self->recalculate;	994	$arg_self->recalculate;
304	});	995	});
305	return;	996	return;
306	}	997	}
307		998
308	$self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	999	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
309		1000
310	# set environment to evaluate user expression	1001	# set environment to evaluate user expression
311		1002
312	local $bgdsl_self = $self;	1003	local $self = $arg_self;
		1004	local $HOME = $ENV{HOME};
		1005	local $frame = [];
313		1006
314	local $old = $self->{state};	1007	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
315	local $new = my $state = $self->{state} = {};
316
317	my $border = 0; #d#
318
319	($x, $y, $w, $h) =
320	$self->background_geometry ($border);
321		1008
322	# evaluate user expression	1009	# evaluate user expression
323		1010
324	my $img = eval { $self->{expr}->() };	1011	my @img = eval { $self->{expr}->() };
325	warn $@ if $@;#d#	1012	die $@ if $@;
		1013	die "background-expr did not return anything.\n" unless @img;
		1014	die "background-expr: expected image(s), got something else.\n"
326	die if !UNIVERSAL::isa $img, "urxvt::img";	1015	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
		1016
		1017	my $img = urxvt::bgdsl::merge @img;
		1018
		1019	$frame->[FR_AGAIN]{size} = 1
		1020	if $img->repeat_mode != urxvt::RepeatNormal;
327		1021
328	# if the expression is sensitive to external events, prepare reevaluation then	1022	# if the expression is sensitive to external events, prepare reevaluation then
329		1023	$self->compile_frame ($frame, sub { $arg_self->recalculate });
330	my $repeat;
331
332	if (my $again = $state->{again}) {
333	$repeat = 1;
334	$state->{timer} = $again == $old->{again}
335	? $old->{timer}
336	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
337	++$self->{counter};
338	$self->recalculate
339	});
340	}
341
342	if (delete $state->{position_sensitive}) {
343	$repeat = 1;
344	$self->enable (position_change => sub { $_[0]->recalculate });
345	} else {
346	$self->disable ("position_change");
347	}
348
349	if (delete $state->{size_sensitive}) {
350	$repeat = 1;
351	$self->enable (size_change => sub { $_[0]->recalculate });
352	} else {
353	$self->disable ("size_change");
354	}
355
356	if (delete $state->{rootpmap_sensitive}) {
357	$repeat = 1;
358	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
359	} else {
360	$self->disable ("rootpmap_change");
361	}
362		1024
363	# clear stuff we no longer need	1025	# clear stuff we no longer need
364		1026
365	%$old = ();	1027	# unless (%{ $frame->[FR_STATE] }) {
366
367	unless ($repeat) {
368	delete $self->{state};	1028	# delete $self->{state};
369	delete $self->{expr};	1029	# delete $self->{expr};
370	}	1030	# }
371		1031
372	# prepare and set background pixmap	1032	# set background pixmap
373		1033
374	$img = $img->sub_rect (0, 0, $w, $h)
375	if $img->w != $w \|\| $img->h != $h;
376
377	$self->set_background ($img, $border);	1034	$self->set_background ($img, $self->{border});
378	$self->scr_recolour (0);	1035	$self->scr_recolour (0);
379	$self->want_refresh;	1036	$self->want_refresh;
380	}	1037	}
381		1038
382	sub on_start {	1039	sub on_start {
383	my ($self) = @_;	1040	my ($self) = @_;
384		1041
		1042	my $expr = $self->x_resource ("%.expr")
		1043	or return;
		1044
		1045	$self->has_render
		1046	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1047
385	$self->set_expr (parse_expr $EXPR);	1048	$self->set_expr (parse_expr $expr);
		1049	$self->{border} = $self->x_resource_boolean ("%.border");
		1050
		1051	$MIN_INTERVAL = $self->x_resource ("%.interval");
386		1052
387	()	1053	()
388	}	1054	}
389		1055

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.30 by root, Thu Jun 7 13:22:06 2012 UTC vs. Revision 1.69 by root, Mon Jul 2 01:32:26 2012 UTC

Diff Legend

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.30 by root, Thu Jun 7 13:22:06 2012 UTC vs.
Revision 1.69 by root, Mon Jul 2 01:32:26 2012 UTC