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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.33 by root, Thu Jun 7 16:30:58 2012 UTC vs.
Revision 1.77 by root, Tue Sep 4 11:21:11 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:%.border.:boolean:respect the terminal border	4	#:META:X_RESOURCE:%.border:boolean:respect the terminal border
		5	#:META:X_RESOURCE:%.interval:seconds:minimum time between updates
5		6
		7	=head1 NAME
		8
6	=head1 background - manage terminal background	9	background - manage terminal background
7		10
8	=head2 SYNOPSIS	11	=head1 SYNOPSIS
9		12
10	rxvt -background-expr 'background expression'	13	urxvt --background-expr 'background expression'
11	-background-border	14	--background-border
		15	--background-interval seconds
12		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
13	=head2 DESCRIPTION	41	=head1 DESCRIPTION
14		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
15	=head2 REFERENCE	250	=head1 REFERENCE
16		251
17	=cut	252	=head2 COMMAND LINE SWITCHES
18		253
19	our $EXPR;	254	=over 4
20	#$EXPR = 'move W * 0.1, -H * 0.1, resize W * 0.5, H * 0.5, repeat_none load "opensource.png"';
21	$EXPR = 'move -TX, -TY, load "argb.png"';
22	#$EXPR = '
23	# rotate W, H, 50, 50, counter 1/59.95, repeat_mirror,
24	# clip X, Y, W, H, repeat_mirror,
25	# load "/root/pix/das_fette_schwein.jpg"
26	#';
27	#$EXPR = 'solid "red"';
28	#$EXPR = 'blur root, 10, 10'
29	#$EXPR = 'blur move (root, -x, -y), 5, 5'
30	#resize load "/root/pix/das_fette_schwein.jpg", w, h
31		255
32	our ($self, $old, $new);	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, $frame);
33	our ($x, $y, $w, $h);	284	our ($x, $y, $w, $h);
34		285
35	# enforce at least this interval between updates	286	# enforce at least this interval between updates
36	our $MIN_INTERVAL = 1/100;	287	our $MIN_INTERVAL = 6/59.951;
37		288
38	{	289	{
39	package urxvt::bgdsl; # background language	290	package urxvt::bgdsl; # background language
		291
		292	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
		293	sub FR_CACHE () { 1 } # cached values
		294	sub FR_AGAIN () { 2 } # what this expr is sensitive to
		295	sub FR_STATE () { 3 } # watchers etc.
		296
		297	use List::Util qw(min max sum shuffle);
40		298
41	=head2 PROVIDERS/GENERATORS	299	=head2 PROVIDERS/GENERATORS
42		300
43	These functions provide an image, by loading it from disk, grabbing it	301	These functions provide an image, by loading it from disk, grabbing it
44	from the root screen or by simply generating it. They are used as starting	302	from the root screen or by simply generating it. They are used as starting
49	=item load $path	307	=item load $path
50		308
51	Loads the image at the given C<$path>. The image is set to plane tiling	309	Loads the image at the given C<$path>. The image is set to plane tiling
52	mode.	310	mode.
53		311
54	Loaded images will be cached for one cycle.	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.
55		314
		315	=item load_uc $path
		316
		317	Load uncached - same as load, but does not cache the image, which means it
		318	is I<always> loaded from the filesystem again, even if another copy of it
		319	is in memory at the time.
		320
56	=cut	321	=cut
		322
		323	sub load_uc($) {
		324	$self->new_img_from_file ($_[0])
		325	}
57		326
58	sub load($) {	327	sub load($) {
59	my ($path) = @_;	328	my ($path) = @_;
60		329
61	$new->{load}{$path} = $old->{load}{$path} \|\| $self->new_img_from_file ($path);	330	$_IMG_CACHE{$path} \|\| do {
		331	my $img = load_uc $path;
		332	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		333	$img
		334	}
62	}	335	}
63		336
64	=item root	337	=item root
65		338
66	Returns the root window pixmap, that is, hopefully, the background image	339	Returns the root window pixmap, that is, hopefully, the background image
67	of your screen. The image is set to extend mode.	340	of your screen.
68		341
69	This function makes your expression root sensitive, that means it will be	342	This function makes your expression root sensitive, that means it will be
70	reevaluated when the bg image changes.	343	reevaluated when the bg image changes.
71		344
72	=cut	345	=cut
73		346
74	sub root() {	347	sub root() {
75	$new->{rootpmap_sensitive} = 1;	348	$frame->[FR_AGAIN]{rootpmap} = 1;
76	die "root op not supported, exg, we need you";	349	$self->new_img_from_root
77	}	350	}
78		351
79	=item solid $colour	352	=item solid $colour
80		353
81	=item solid $width, $height, $colour	354	=item solid $width, $height, $colour
82		355
83	Creates a new image and completely fills it with the given colour. The	356	Creates a new image and completely fills it with the given colour. The
84	image is set to tiling mode.	357	image is set to tiling mode.
85		358
86	If <$width> and C<$height> are omitted, it creates a 1x1 image, which is	359	If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
87	useful for solid backgrounds or for use in filtering effects.	360	useful for solid backgrounds or for use in filtering effects.
88		361
89	=cut	362	=cut
90		363
91	sub solid($$;$) {	364	sub solid($;$$) {
92	my $colour = pop;	365	my $colour = pop;
93		366
94	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	367	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
95	$img->fill ($colour);	368	$img->fill ($colour);
96	$img	369	$img
97	}	370	}
98		371
99	=back	372	=item clone $img
100		373
101	=head2 VARIABLES	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.
102		376
103	The following functions provide variable data such as the terminal
104	window dimensions. Most of them make your expression sensitive to some
105	events, for example using C<TW> (terminal width) means your expression is
106	evaluated again when the terminal is resized.
107
108	=over 4
109
110	=item TX
111
112	=item TY
113
114	Return the X and Y coordinates of the terminal window (the terminal
115	window is the full window by default, and the character area only when in
116	border-respect mode).
117
118	Using these functions make your expression sensitive to window moves.
119
120	These functions are mainly useful to align images to the root window.
121
122	Example: load an image and align it so it looks as if anchored to the
123	background.
124
125	move -TX, -TY, load "mybg.png"
126
127	=item TW
128
129	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
130	terminal window is the full window by default, and the character area only
131	when in border-respect mode).
132
133	Using these functions make your expression sensitive to window resizes.
134
135	These functions are mainly useful to scale images, or to clip images to
136	the window size to conserve memory.
137
138	Example: take the screen background, clip it to the window size, blur it a
139	bit, align it to the window position and use it as background.
140
141	clip move -TX, -TY, blur 5, root
142
143	=cut	377	=cut
144		378
145	sub TX() { $new->{position_sensitive} = 1; $x }
146	sub TY() { $new->{position_sensitive} = 1; $y }
147	sub TW() { $new->{size_sensitive} = 1; $w }
148	sub TH() { $new->{size_sensitive} = 1; $h }
149
150	=item now
151
152	Returns the current time as (fractional) seconds since the epoch.
153
154	Using this expression does I<not> make your expression sensitive to time,
155	but the next two functions do.
156
157	=item again $seconds
158
159	When this function is used the expression will be reevaluated again in
160	C<$seconds> seconds.
161
162	Example: load some image and rotate it according to the time of day (as if it were
163	the hour pointer of a clock). update this image every minute.
164
165	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
166
167	=item counter $seconds
168
169	Like C<again>, but also returns an increasing counter value, starting at
170	0, which might be useful for some simple animation effects.
171
172	=cut
173
174	sub now() { urxvt::NOW }
175
176	sub again($) {
177	$new->{again} = $_[0];
178	}
179
180	sub counter($) {	379	sub clone($) {
181	$new->{again} = $_[0];	380	$_[0]->clone
182	$self->{counter} + 0	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
183	}	425	}
184		426
185	=back	427	=back
186		428
187	=head2 TILING MODES	429	=head2 TILING MODES
…		…
193		435
194	=item tile $img	436	=item tile $img
195		437
196	Tiles the whole plane with the image and returns this new image - or in	438	Tiles the whole plane with the image and returns this new image - or in
197	other words, it returns a copy of the image in plane tiling mode.	439	other words, it returns a copy of the image in plane tiling mode.
		440
		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.
		444
		445	tile load "mybg.png"
198		446
199	=item mirror $img	447	=item mirror $img
200		448
201	Similar to tile, but reflects the image each time it uses a new copy, so	449	Similar to tile, but reflects the image each time it uses a new copy, so
202	that top edges always touch top edges, right edges always touch right	450	that top edges always touch top edges, right edges always touch right
203	edges and so on (with normal tiling, left edges always touch right edges	451	edges and so on (with normal tiling, left edges always touch right edges
204	and top always touch bottom edges).	452	and top always touch bottom edges).
205		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
206	=item pad $img	459	=item pad $img
207		460
208	Takes an image and modifies it so that all pixels outside the image area	461	Takes an image and modifies it so that all pixels outside the image area
209	become transparent. This mode is most useful when you want to place an	462	become transparent. This mode is most useful when you want to place an
210	image over another image or the background colour while leaving all	463	image over another image or the background colour while leaving all
211	background pixels outside the image unchanged.	464	background pixels outside the image unchanged.
212		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
213	=item extend $img	472	=item extend $img
214		473
215	Extends the image over the whole plane, using the closest pixel in the	474	Extends the image over the whole plane, using the closest pixel in the
216	area outside the image. This mode is mostly useful when you more complex	475	area outside the image. This mode is mostly useful when you use more complex
217	filtering operations and want the pixels outside the image to have the	476	filtering operations and want the pixels outside the image to have the
218	same values as the pixels near the edge.	477	same values as the pixels near the edge.
		478
		479	Example: just for curiosity, how does this pixel extension stuff work?
		480
		481	extend move 50, 50, load "mybg.png"
219		482
220	=cut	483	=cut
221		484
222	sub pad($) {	485	sub pad($) {
223	my $img = $_[0]->clone;	486	my $img = $_[0]->clone;
…		…
243	$img	506	$img
244	}	507	}
245		508
246	=back	509	=back
247		510
248	=head2 PIXEL OPERATORS	511	=head2 VARIABLE VALUES
249		512
250	The following operators modify the image pixels in various ways.	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.
251		518
252	=over 4	519	=over 4
253		520
254	=item clone $img	521	=item TX
255		522
256	Returns an exact copy of the image.	523	=item TY
257		524
258	=cut	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).
259		528
		529	Using these functions make 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 make 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	=cut
		557
		558	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
		559	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
		560	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
		561	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
		562
		563	=item now
		564
		565	Returns the current time as (fractional) seconds since the epoch.
		566
		567	Using this expression does I<not> make your expression sensitive to time,
		568	but the next two functions do.
		569
		570	=item again $seconds
		571
		572	When this function is used the expression will be reevaluated again in
		573	C<$seconds> seconds.
		574
		575	Example: load some image and rotate it according to the time of day (as if it were
		576	the hour pointer of a clock). Update this image every minute.
		577
		578	again 60;
		579	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
		580
		581	=item counter $seconds
		582
		583	Like C<again>, but also returns an increasing counter value, starting at
		584	0, which might be useful for some simple animation effects.
		585
		586	=cut
		587
		588	sub now() { urxvt::NOW }
		589
		590	sub again($) {
		591	$frame->[FR_AGAIN]{time} = $_[0];
		592	}
		593
260	sub clone($) {	594	sub counter($) {
261	$_[0]->clone	595	$frame->[FR_AGAIN]{time} = $_[0];
		596	$frame->[FR_STATE]{counter} + 0
262	}	597	}
		598
		599	=back
		600
		601	=head2 SHAPE CHANGING OPERATORS
		602
		603	The following operators modify the shape, size or position of the image.
		604
		605	=over 4
263		606
264	=item clip $img	607	=item clip $img
265		608
266	=item clip $width, $height, $img	609	=item clip $width, $height, $img
267		610
…		…
278	assumed.	621	assumed.
279		622
280	Example: load an image, blur it, and clip it to the window size to save	623	Example: load an image, blur it, and clip it to the window size to save
281	memory.	624	memory.
282		625
283	clip blur 10, load "mybg.png"	626	clip keep { blur 10, load "mybg.png" }
284		627
285	=cut	628	=cut
286		629
287	sub clip($;$$;$$) {	630	sub clip($;$$;$$) {
288	my $img = pop;	631	my $img = pop;
…		…
291	$img->sub_rect ($_[0], $_[1], $w, $h)	634	$img->sub_rect ($_[0], $_[1], $w, $h)
292	}	635	}
293		636
294	=item scale $img	637	=item scale $img
295		638
296	=item scale $size_percent, $img	639	=item scale $size_factor, $img
297		640
298	=item scale $width_percent, $height_percent, $img	641	=item scale $width_factor, $height_factor, $img
299		642
300	Scales the image by the given percentages in horizontal	643	Scales the image by the given factors in horizontal
301	(C<$width_percent>) and vertical (C<$height_percent>) direction.	644	(C<$width>) and vertical (C<$height>) direction.
302		645
303	If only one percentage is give, it is used for both directions.	646	If only one factor is give, it is used for both directions.
304		647
305	If no percentages are given, scales the image to the window size without	648	If no factors are given, scales the image to the window size without
306	keeping aspect.	649	keeping aspect.
307		650
308	=item resize $width, $height, $img	651	=item resize $width, $height, $img
309		652
310	Resizes the image to exactly C<$width> times C<$height> pixels.	653	Resizes the image to exactly C<$width> times C<$height> pixels.
311		654
312	=cut	655	=item fit $img
313		656
314	#TODO: maximise, maximise_fill?	657	=item fit $width, $height, $img
		658
		659	Fits the image into the given C<$width> and C<$height> without changing
		660	aspect, or the terminal size. That means it will be shrunk or grown until
		661	the whole image fits into the given area, possibly leaving borders.
		662
		663	=item cover $img
		664
		665	=item cover $width, $height, $img
		666
		667	Similar to C<fit>, but shrinks or grows until all of the area is covered
		668	by the image, so instead of potentially leaving borders, it will cut off
		669	image data that doesn't fit.
		670
		671	=cut
315		672
316	sub scale($;$;$) {	673	sub scale($;$;$) {
317	my $img = pop;	674	my $img = pop;
318		675
319	@_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01)	676	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
320	: @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01)	677	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
321	: $img->scale (TW, TH)	678	: $img->scale (TW, TH)
322	}	679	}
323		680
324	sub resize($$$) {	681	sub resize($$$) {
325	my $img = pop;	682	my $img = pop;
326	$img->scale ($_[0], $_[1])	683	$img->scale ($_[0], $_[1])
327	}	684	}
		685
		686	sub fit($;$$) {
		687	my $img = pop;
		688	my $w = ($_[0] \|\| TW) / $img->w;
		689	my $h = ($_[1] \|\| TH) / $img->h;
		690	scale +(min $w, $h), $img
		691	}
		692
		693	sub cover($;$$) {
		694	my $img = pop;
		695	my $w = ($_[0] \|\| TW) / $img->w;
		696	my $h = ($_[1] \|\| TH) / $img->h;
		697	scale +(max $w, $h), $img
		698	}
		699
		700	=item move $dx, $dy, $img
		701
		702	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
		703	the vertical.
		704
		705	Example: move the image right by 20 pixels and down by 30.
		706
		707	move 20, 30, ...
		708
		709	=item align $xalign, $yalign, $img
		710
		711	Aligns the image according to a factor - C<0> means the image is moved to
		712	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		713	exactly centered and C<1> means it touches the right or bottom edge.
		714
		715	Example: remove any visible border around an image, center it vertically but move
		716	it to the right hand side.
		717
		718	align 1, 0.5, pad $img
		719
		720	=item center $img
		721
		722	=item center $width, $height, $img
		723
		724	Centers the image, i.e. the center of the image is moved to the center of
		725	the terminal window (or the box specified by C<$width> and C<$height> if
		726	given).
		727
		728	Example: load an image and center it.
		729
		730	center keep { pad load "mybg.png" }
		731
		732	=item rootalign $img
		733
		734	Moves the image so that it appears glued to the screen as opposed to the
		735	window. This gives the illusion of a larger area behind the window. It is
		736	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
		737	top left of the screen.
		738
		739	Example: load a background image, put it in mirror mode and root align it.
		740
		741	rootalign keep { mirror load "mybg.png" }
		742
		743	Example: take the screen background and align it, giving the illusion of
		744	transparency as long as the window isn't in front of other windows.
		745
		746	rootalign root
		747
		748	=cut
328		749
329	sub move($$;$) {	750	sub move($$;$) {
330	my $img = pop->clone;	751	my $img = pop->clone;
331	$img->move ($_[0], $_[1]);	752	$img->move ($_[0], $_[1]);
332	$img	753	$img
333	}	754	}
334		755
		756	sub align($;$$) {
		757	my $img = pop;
		758
		759	move $_[0] * (TW - $img->w),
		760	$_[1] * (TH - $img->h),
		761	$img
		762	}
		763
		764	sub center($;$$) {
		765	my $img = pop;
		766	my $w = $_[0] \|\| TW;
		767	my $h = $_[1] \|\| TH;
		768
		769	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		770	}
		771
		772	sub rootalign($) {
		773	move -TX, -TY, $_[0]
		774	}
		775
		776	=item rotate $center_x, $center_y, $degrees, $img
		777
		778	Rotates the image clockwise by C<$degrees> degrees, around the point at
		779	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		780
		781	Example: rotate the image by 90 degrees around it's center.
		782
		783	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		784
		785	=cut
		786
335	sub rotate($$$$$$) {	787	sub rotate($$$$) {
336	my $img = pop;	788	my $img = pop;
337	$img->rotate (	789	$img->rotate (
338	$_[0],	790	$_[0] * ($img->w + $img->x),
339	$_[1],	791	$_[1] * ($img->h + $img->y),
340	$_[2] * $img->w * .01,
341	$_[3] * $img->h * .01,
342	$_[4] * (3.14159265 / 180),	792	$_[2] * (3.14159265 / 180),
343	)	793	)
344	}	794	}
		795
		796	=back
		797
		798	=head2 COLOUR MODIFICATIONS
		799
		800	The following operators change the pixels of the image.
		801
		802	=over 4
		803
		804	=item tint $color, $img
		805
		806	Tints the image in the given colour.
		807
		808	Example: tint the image red.
		809
		810	tint "red", load "rgb.png"
		811
		812	Example: the same, but specify the colour by component.
		813
		814	tint [1, 0, 0], load "rgb.png"
		815
		816	=cut
		817
		818	sub tint($$) {
		819	$_[1]->tint ($_[0])
		820	}
		821
		822	=item contrast $factor, $img
		823
		824	=item contrast $r, $g, $b, $img
		825
		826	=item contrast $r, $g, $b, $a, $img
		827
		828	Adjusts the I<contrast> of an image.
		829
		830	The first form applies a single C<$factor> to red, green and blue, the
		831	second form applies separate factors to each colour channel, and the last
		832	form includes the alpha channel.
		833
		834	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		835	contrast.
		836
		837	Due to limitations in the underlying XRender extension, lowering contrast
		838	also reduces brightness, while increasing contrast currently also
		839	increases brightness.
		840
		841	=item brightness $bias, $img
		842
		843	=item brightness $r, $g, $b, $img
		844
		845	=item brightness $r, $g, $b, $a, $img
		846
		847	Adjusts the brightness of an image.
		848
		849	The first form applies a single C<$bias> to red, green and blue, the
		850	second form applies separate biases to each colour channel, and the last
		851	form includes the alpha channel.
		852
		853	Values less than 0 reduce brightness, while values larger than 0 increase
		854	it. Useful range is from -1 to 1 - the former results in a black, the
		855	latter in a white picture.
		856
		857	Due to idiosyncrasies in the underlying XRender extension, biases less
		858	than zero can be I<very> slow.
		859
		860	You can also try the experimental(!) C<muladd> operator.
		861
		862	=cut
		863
		864	sub contrast($$;$$;$) {
		865	my $img = pop;
		866	my ($r, $g, $b, $a) = @_;
		867
		868	($g, $b) = ($r, $r) if @_ < 3;
		869	$a = 1 if @_ < 4;
		870
		871	$img = $img->clone;
		872	$img->contrast ($r, $g, $b, $a);
		873	$img
		874	}
		875
		876	sub brightness($$;$$;$) {
		877	my $img = pop;
		878	my ($r, $g, $b, $a) = @_;
		879
		880	($g, $b) = ($r, $r) if @_ < 3;
		881	$a = 1 if @_ < 4;
		882
		883	$img = $img->clone;
		884	$img->brightness ($r, $g, $b, $a);
		885	$img
		886	}
		887
		888	=item muladd $mul, $add, $img # EXPERIMENTAL
		889
		890	First multipliesthe pixels by C<$mul>, then adds C<$add>. This cna be used
		891	to implement brightness and contrast at the same time, with a wider value
		892	range than contrast and brightness operators.
		893
		894	Due to numerous bugs in XRender implementations, it can also introduce a
		895	number of visual artifacts.
		896
		897	Example: increase contrast by a factor of C<$c> without changing image
		898	brightness too much.
		899
		900	muladd $c, (1 - $c) * 0.5, $img
		901
		902	=cut
		903
		904	sub muladd($$$) {
		905	$_[2]->muladd ($_[0], $_[1])
		906	}
		907
		908	=item blur $radius, $img
		909
		910	=item blur $radius_horz, $radius_vert, $img
		911
		912	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
		913	can also be specified separately.
		914
		915	Blurring is often I<very> slow, at least compared or other
		916	operators. Larger blur radii are slower than smaller ones, too, so if you
		917	don't want to freeze your screen for long times, start experimenting with
		918	low values for radius (<5).
		919
		920	=cut
345		921
346	sub blur($$;$) {	922	sub blur($$;$) {
347	my $img = pop;	923	my $img = pop;
348	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	924	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
349	}	925	}
350		926
351	sub contrast($$;$$;$) {
352	my $img = pop;
353	my ($r, $g, $b, $a) = @_;
354
355	($g, $b) = ($r, $r) if @_ < 4;
356	$a = 1 if @_ < 5;
357
358	$img = $img->clone;
359	$img->contrast ($r, $g, $b, $a);
360	$img
361	}
362
363	sub brightness($$;$$;$) {
364	my $img = pop;
365	my ($r, $g, $b, $a) = @_;
366
367	($g, $b) = ($r, $r) if @_ < 4;
368	$a = 1 if @_ < 5;
369
370	$img = $img->clone;
371	$img->brightness ($r, $g, $b, $a);
372	$img
373	}
374
375	=back	927	=back
376		928
		929	=head2 OTHER STUFF
		930
		931	Anything that didn't fit any of the other categories, even after applying
		932	force and closing our eyes.
		933
		934	=over 4
		935
		936	=item keep { ... }
		937
		938	This operator takes a code block as argument, that is, one or more
		939	statements enclosed by braces.
		940
		941	The trick is that this code block is only evaluated when the outcome
		942	changes - on other calls the C<keep> simply returns the image it computed
		943	previously (yes, it should only be used with images). Or in other words,
		944	C<keep> I<caches> the result of the code block so it doesn't need to be
		945	computed again.
		946
		947	This can be extremely useful to avoid redoing slow operations - for
		948	example, if your background expression takes the root background, blurs it
		949	and then root-aligns it it would have to blur the root background on every
		950	window move or resize.
		951
		952	Another example is C<load>, which can be quite slow.
		953
		954	In fact, urxvt itself encloses the whole expression in some kind of
		955	C<keep> block so it only is reevaluated as required.
		956
		957	Putting the blur into a C<keep> block will make sure the blur is only done
		958	once, while the C<rootalign> is still done each time the window moves.
		959
		960	rootalign keep { blur 10, root }
		961
		962	This leaves the question of how to force reevaluation of the block,
		963	in case the root background changes: If expression inside the block
		964	is sensitive to some event (root background changes, window geometry
		965	changes), then it will be reevaluated automatically as needed.
		966
		967	=cut
		968
		969	sub keep(&) {
		970	my $id = $_[0]+0;
		971
		972	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		973
		974	unless ($frame->[FR_CACHE]) {
		975	$frame->[FR_CACHE] = [ $_[0]() ];
		976
		977	my $self = $self;
		978	my $frame = $frame;
		979	Scalar::Util::weaken $frame;
		980	$self->compile_frame ($frame, sub {
		981	# clear this frame cache, also for all parents
		982	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		983	undef $frame->[FR_CACHE];
		984	}
		985
		986	$self->recalculate;
		987	});
		988	};
		989
		990	# in scalar context we always return the first original result, which
		991	# is not quite how perl works.
		992	wantarray
		993	? @{ $frame->[FR_CACHE] }
		994	: $frame->[FR_CACHE][0]
		995	}
		996
		997	# sub keep_clear() {
		998	# delete $self->{frame_cache};
		999	# }
		1000
		1001	=back
		1002
377	=cut	1003	=cut
378		1004
379	}	1005	}
380		1006
381	sub parse_expr {	1007	sub parse_expr {
382	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	1008	my $expr = eval
		1009	"sub {\n"
		1010	. "package urxvt::bgdsl;\n"
		1011	. "#line 0 'background expression'\n"
		1012	. "$_[0]\n"
		1013	. "}";
383	die if $@;	1014	die if $@;
384	$expr	1015	$expr
385	}	1016	}
386		1017
387	# compiles a parsed expression	1018	# compiles a parsed expression
388	sub set_expr {	1019	sub set_expr {
389	my ($self, $expr) = @_;	1020	my ($self, $expr) = @_;
390		1021
		1022	$self->{root} = []; # the outermost frame
391	$self->{expr} = $expr;	1023	$self->{expr} = $expr;
392	$self->recalculate;	1024	$self->recalculate;
		1025	}
		1026
		1027	# takes a hash of sensitivity indicators and installs watchers
		1028	sub compile_frame {
		1029	my ($self, $frame, $cb) = @_;
		1030
		1031	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		1032	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		1033
		1034	# don't keep stuff alive
		1035	Scalar::Util::weaken $state;
		1036
		1037	if ($again->{nested}) {
		1038	$state->{nested} = 1;
		1039	} else {
		1040	delete $state->{nested};
		1041	}
		1042
		1043	if (my $interval = $again->{time}) {
		1044	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		1045	if $state->{time}[0] != $interval;
		1046
		1047	# callback might have changed, although we could just rule that out
		1048	$state->{time}[1]->cb (sub {
		1049	++$state->{counter};
		1050	$cb->();
		1051	});
		1052	} else {
		1053	delete $state->{time};
		1054	}
		1055
		1056	if ($again->{position}) {
		1057	$state->{position} = $self->on (position_change => $cb);
		1058	} else {
		1059	delete $state->{position};
		1060	}
		1061
		1062	if ($again->{size}) {
		1063	$state->{size} = $self->on (size_change => $cb);
		1064	} else {
		1065	delete $state->{size};
		1066	}
		1067
		1068	if ($again->{rootpmap}) {
		1069	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		1070	} else {
		1071	delete $state->{rootpmap};
		1072	}
393	}	1073	}
394		1074
395	# evaluate the current bg expression	1075	# evaluate the current bg expression
396	sub recalculate {	1076	sub recalculate {
397	my ($arg_self) = @_;	1077	my ($arg_self) = @_;
…		…
407		1087
408	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1088	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
409		1089
410	# set environment to evaluate user expression	1090	# set environment to evaluate user expression
411		1091
412	local $self = $arg_self;	1092	local $self = $arg_self;
413		1093	local $HOME = $ENV{HOME};
414	local $old = $self->{state};	1094	local $frame = $self->{root};
415	local $new = my $state = $self->{state} = {};
416		1095
417	($x, $y, $w, $h) =
418	$self->background_geometry ($self->{border});	1096	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
419		1097
420	# evaluate user expression	1098	# evaluate user expression
421		1099
422	my $img = eval { $self->{expr}->() };	1100	my @img = eval { $self->{expr}->() };
423	warn $@ if $@;#d#	1101	die $@ if $@;
		1102	die "background-expr did not return anything.\n" unless @img;
		1103	die "background-expr: expected image(s), got something else.\n"
424	die if !UNIVERSAL::isa $img, "urxvt::img";	1104	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
		1105
		1106	my $img = urxvt::bgdsl::merge @img;
		1107
		1108	$frame->[FR_AGAIN]{size} = 1
		1109	if $img->repeat_mode != urxvt::RepeatNormal;
425		1110
426	# if the expression is sensitive to external events, prepare reevaluation then	1111	# if the expression is sensitive to external events, prepare reevaluation then
427		1112	$self->compile_frame ($frame, sub { $arg_self->recalculate });
428	my $repeat;
429
430	if (my $again = $state->{again}) {
431	$repeat = 1;
432	$state->{timer} = $again == $old->{again}
433	? $old->{timer}
434	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
435	++$self->{counter};
436	$self->recalculate
437	});
438	}
439
440	if (delete $state->{position_sensitive}) {
441	$repeat = 1;
442	$self->enable (position_change => sub { $_[0]->recalculate });
443	} else {
444	$self->disable ("position_change");
445	}
446
447	if (delete $state->{size_sensitive}) {
448	$repeat = 1;
449	$self->enable (size_change => sub { $_[0]->recalculate });
450	} else {
451	$self->disable ("size_change");
452	}
453
454	if (delete $state->{rootpmap_sensitive}) {
455	$repeat = 1;
456	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
457	} else {
458	$self->disable ("rootpmap_change");
459	}
460		1113
461	# clear stuff we no longer need	1114	# clear stuff we no longer need
462		1115
463	%$old = ();	1116	# unless (%{ $frame->[FR_STATE] }) {
464
465	unless ($repeat) {
466	delete $self->{state};	1117	# delete $self->{state};
467	delete $self->{expr};	1118	# delete $self->{expr};
468	}	1119	# }
469		1120
470	# prepare and set background pixmap	1121	# set background pixmap
471
472	$img = $img->sub_rect (0, 0, $w, $h)
473	if $img->w != $w \|\| $img->h != $h;
474		1122
475	$self->set_background ($img, $self->{border});	1123	$self->set_background ($img, $self->{border});
476	$self->scr_recolour (0);	1124	$self->scr_recolour (0);
477	$self->want_refresh;	1125	$self->want_refresh;
478	}	1126	}
479		1127
480	sub on_start {	1128	sub on_start {
481	my ($self) = @_;	1129	my ($self) = @_;
482		1130
483	my $expr = $self->x_resource ("background.expr")	1131	my $expr = $self->x_resource ("%.expr")
484	or return;	1132	or return;
485		1133
		1134	$self->has_render
		1135	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1136
486	$self->set_expr (parse_expr $expr);	1137	$self->set_expr (parse_expr $expr);
487	$self->{border} = $self->x_resource_boolean ("background.border");	1138	$self->{border} = $self->x_resource_boolean ("%.border");
		1139
		1140	$MIN_INTERVAL = $self->x_resource ("%.interval");
488		1141
489	()	1142	()
490	}	1143	}
491		1144

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.33 by root, Thu Jun 7 16:30:58 2012 UTC vs. Revision 1.77 by root, Tue Sep 4 11:21:11 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.33 by root, Thu Jun 7 16:30:58 2012 UTC vs.
Revision 1.77 by root, Tue Sep 4 11:21:11 2012 UTC