[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 1.76 by root, Tue Aug 14 23:57:07 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	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		541	terminal window is the full window by default, and the character area only
		542	when in border-respect mode).
		543
		544	Using these functions make your expression sensitive to window resizes.
		545
		546	These functions are mainly useful to scale images, or to clip images to
		547	the window size to conserve memory.
		548
		549	Example: take the screen background, clip it to the window size, blur it a
		550	bit, align it to the window position and use it as background.
		551
		552	clip move -TX, -TY, keep { blur 5, root }
		553
		554	=cut
		555
		556	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
		557	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
		558	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
		559	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
		560
		561	=item now
		562
		563	Returns the current time as (fractional) seconds since the epoch.
		564
		565	Using this expression does I<not> make your expression sensitive to time,
		566	but the next two functions do.
		567
		568	=item again $seconds
		569
		570	When this function is used the expression will be reevaluated again in
		571	C<$seconds> seconds.
		572
		573	Example: load some image and rotate it according to the time of day (as if it were
		574	the hour pointer of a clock). Update this image every minute.
		575
		576	again 60;
		577	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
		578
		579	=item counter $seconds
		580
		581	Like C<again>, but also returns an increasing counter value, starting at
		582	0, which might be useful for some simple animation effects.
		583
		584	=cut
		585
		586	sub now() { urxvt::NOW }
		587
		588	sub again($) {
		589	$frame->[FR_AGAIN]{time} = $_[0];
		590	}
		591
260	sub clone($) {	592	sub counter($) {
261	$_[0]->clone	593	$frame->[FR_AGAIN]{time} = $_[0];
		594	$frame->[FR_STATE]{counter} + 0
262	}	595	}
		596
		597	=back
		598
		599	=head2 SHAPE CHANGING OPERATORS
		600
		601	The following operators modify the shape, size or position of the image.
		602
		603	=over 4
263		604
264	=item clip $img	605	=item clip $img
265		606
266	=item clip $width, $height, $img	607	=item clip $width, $height, $img
267		608
…		…
278	assumed.	619	assumed.
279		620
280	Example: load an image, blur it, and clip it to the window size to save	621	Example: load an image, blur it, and clip it to the window size to save
281	memory.	622	memory.
282		623
283	clip blur 10, load "mybg.png"	624	clip keep { blur 10, load "mybg.png" }
284		625
285	=cut	626	=cut
286		627
287	sub clip($;$$;$$) {	628	sub clip($;$$;$$) {
288	my $img = pop;	629	my $img = pop;
…		…
291	$img->sub_rect ($_[0], $_[1], $w, $h)	632	$img->sub_rect ($_[0], $_[1], $w, $h)
292	}	633	}
293		634
294	=item scale $img	635	=item scale $img
295		636
296	=item scale $size_percent, $img	637	=item scale $size_factor, $img
297		638
298	=item scale $width_percent, $height_percent, $img	639	=item scale $width_factor, $height_factor, $img
299		640
300	Scales the image by the given percentages in horizontal	641	Scales the image by the given factors in horizontal
301	(C<$width_percent>) and vertical (C<$height_percent>) direction.	642	(C<$width>) and vertical (C<$height>) direction.
302		643
303	If only one percentage is give, it is used for both directions.	644	If only one factor is give, it is used for both directions.
304		645
305	If no percentages are given, scales the image to the window size without	646	If no factors are given, scales the image to the window size without
306	keeping aspect.	647	keeping aspect.
307		648
308	=item resize $width, $height, $img	649	=item resize $width, $height, $img
309		650
310	Resizes the image to exactly C<$width> times C<$height> pixels.	651	Resizes the image to exactly C<$width> times C<$height> pixels.
311		652
312	=cut	653	=item fit $img
313		654
314	#TODO: maximise, maximise_fill?	655	=item fit $width, $height, $img
		656
		657	Fits the image into the given C<$width> and C<$height> without changing
		658	aspect, or the terminal size. That means it will be shrunk or grown until
		659	the whole image fits into the given area, possibly leaving borders.
		660
		661	=item cover $img
		662
		663	=item cover $width, $height, $img
		664
		665	Similar to C<fit>, but shrinks or grows until all of the area is covered
		666	by the image, so instead of potentially leaving borders, it will cut off
		667	image data that doesn't fit.
		668
		669	=cut
315		670
316	sub scale($;$;$) {	671	sub scale($;$;$) {
317	my $img = pop;	672	my $img = pop;
318		673
319	@_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01)	674	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
320	: @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01)	675	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
321	: $img->scale (TW, TH)	676	: $img->scale (TW, TH)
322	}	677	}
323		678
324	sub resize($$$) {	679	sub resize($$$) {
325	my $img = pop;	680	my $img = pop;
326	$img->scale ($_[0], $_[1])	681	$img->scale ($_[0], $_[1])
327	}	682	}
		683
		684	sub fit($;$$) {
		685	my $img = pop;
		686	my $w = ($_[0] \|\| TW) / $img->w;
		687	my $h = ($_[1] \|\| TH) / $img->h;
		688	scale +(min $w, $h), $img
		689	}
		690
		691	sub cover($;$$) {
		692	my $img = pop;
		693	my $w = ($_[0] \|\| TW) / $img->w;
		694	my $h = ($_[1] \|\| TH) / $img->h;
		695	scale +(max $w, $h), $img
		696	}
		697
		698	=item move $dx, $dy, $img
		699
		700	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
		701	the vertical.
		702
		703	Example: move the image right by 20 pixels and down by 30.
		704
		705	move 20, 30, ...
		706
		707	=item align $xalign, $yalign, $img
		708
		709	Aligns the image according to a factor - C<0> means the image is moved to
		710	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		711	exactly centered and C<1> means it touches the right or bottom edge.
		712
		713	Example: remove any visible border around an image, center it vertically but move
		714	it to the right hand side.
		715
		716	align 1, 0.5, pad $img
		717
		718	=item center $img
		719
		720	=item center $width, $height, $img
		721
		722	Centers the image, i.e. the center of the image is moved to the center of
		723	the terminal window (or the box specified by C<$width> and C<$height> if
		724	given).
		725
		726	Example: load an image and center it.
		727
		728	center keep { pad load "mybg.png" }
		729
		730	=item rootalign $img
		731
		732	Moves the image so that it appears glued to the screen as opposed to the
		733	window. This gives the illusion of a larger area behind the window. It is
		734	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
		735	top left of the screen.
		736
		737	Example: load a background image, put it in mirror mode and root align it.
		738
		739	rootalign keep { mirror load "mybg.png" }
		740
		741	Example: take the screen background and align it, giving the illusion of
		742	transparency as long as the window isn't in front of other windows.
		743
		744	rootalign root
		745
		746	=cut
328		747
329	sub move($$;$) {	748	sub move($$;$) {
330	my $img = pop->clone;	749	my $img = pop->clone;
331	$img->move ($_[0], $_[1]);	750	$img->move ($_[0], $_[1]);
332	$img	751	$img
333	}	752	}
334		753
		754	sub align($;$$) {
		755	my $img = pop;
		756
		757	move $_[0] * (TW - $img->w),
		758	$_[1] * (TH - $img->h),
		759	$img
		760	}
		761
		762	sub center($;$$) {
		763	my $img = pop;
		764	my $w = $_[0] \|\| TW;
		765	my $h = $_[1] \|\| TH;
		766
		767	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		768	}
		769
		770	sub rootalign($) {
		771	move -TX, -TY, $_[0]
		772	}
		773
		774	=item rotate $center_x, $center_y, $degrees, $img
		775
		776	Rotates the image clockwise by C<$degrees> degrees, around the point at
		777	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		778
		779	Example: rotate the image by 90 degrees around it's center.
		780
		781	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		782
		783	=cut
		784
335	sub rotate($$$$$$) {	785	sub rotate($$$$) {
336	my $img = pop;	786	my $img = pop;
337	$img->rotate (	787	$img->rotate (
338	$_[0],	788	$_[0] * ($img->w + $img->x),
339	$_[1],	789	$_[1] * ($img->h + $img->y),
340	$_[2] * $img->w * .01,
341	$_[3] * $img->h * .01,
342	$_[4] * (3.14159265 / 180),	790	$_[2] * (3.14159265 / 180),
343	)	791	)
344	}	792	}
		793
		794	=back
		795
		796	=head2 COLOUR MODIFICATIONS
		797
		798	The following operators change the pixels of the image.
		799
		800	=over 4
		801
		802	=item tint $color, $img
		803
		804	Tints the image in the given colour.
		805
		806	Example: tint the image red.
		807
		808	tint "red", load "rgb.png"
		809
		810	Example: the same, but specify the colour by component.
		811
		812	tint [1, 0, 0], load "rgb.png"
		813
		814	=cut
		815
		816	sub tint($$) {
		817	$_[1]->tint ($_[0])
		818	}
		819
		820	=item contrast $factor, $img
		821
		822	=item contrast $r, $g, $b, $img
		823
		824	=item contrast $r, $g, $b, $a, $img
		825
		826	Adjusts the I<contrast> of an image.
		827
		828	The first form applies a single C<$factor> to red, green and blue, the
		829	second form applies separate factors to each colour channel, and the last
		830	form includes the alpha channel.
		831
		832	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		833	contrast.
		834
		835	Due to limitations in the underlying XRender extension, lowering contrast
		836	also reduces brightness, while increasing contrast currently also
		837	increases brightness.
		838
		839	=item brightness $bias, $img
		840
		841	=item brightness $r, $g, $b, $img
		842
		843	=item brightness $r, $g, $b, $a, $img
		844
		845	Adjusts the brightness of an image.
		846
		847	The first form applies a single C<$bias> to red, green and blue, the
		848	second form applies separate biases to each colour channel, and the last
		849	form includes the alpha channel.
		850
		851	Values less than 0 reduce brightness, while values larger than 0 increase
		852	it. Useful range is from -1 to 1 - the former results in a black, the
		853	latter in a white picture.
		854
		855	Due to idiosyncrasies in the underlying XRender extension, biases less
		856	than zero can be I<very> slow.
		857
		858	You can also try the experimental(!) C<muladd> operator.
		859
		860	=cut
		861
		862	sub contrast($$;$$;$) {
		863	my $img = pop;
		864	my ($r, $g, $b, $a) = @_;
		865
		866	($g, $b) = ($r, $r) if @_ < 3;
		867	$a = 1 if @_ < 4;
		868
		869	$img = $img->clone;
		870	$img->contrast ($r, $g, $b, $a);
		871	$img
		872	}
		873
		874	sub brightness($$;$$;$) {
		875	my $img = pop;
		876	my ($r, $g, $b, $a) = @_;
		877
		878	($g, $b) = ($r, $r) if @_ < 3;
		879	$a = 1 if @_ < 4;
		880
		881	$img = $img->clone;
		882	$img->brightness ($r, $g, $b, $a);
		883	$img
		884	}
		885
		886	=item muladd $mul, $add, $img # EXPERIMENTAL
		887
		888	First multipliesthe pixels by C<$mul>, then adds C<$add>. This cna be used
		889	to implement brightness and contrast at the same time, with a wider value
		890	range than contrast and brightness operators.
		891
		892	Due to numerous bugs in XRender implementations, it can also introduce a
		893	number of visual artifacts.
		894
		895	Example: increase contrast by a factor of C<$c> without changing image
		896	brightness too much.
		897
		898	muladd $c, (1 - $c) * 0.5, $img
		899
		900	=cut
		901
		902	sub muladd($$$) {
		903	$_[2]->muladd ($_[0], $_[1])
		904	}
		905
		906	=item blur $radius, $img
		907
		908	=item blur $radius_horz, $radius_vert, $img
		909
		910	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
		911	can also be specified separately.
		912
		913	Blurring is often I<very> slow, at least compared or other
		914	operators. Larger blur radii are slower than smaller ones, too, so if you
		915	don't want to freeze your screen for long times, start experimenting with
		916	low values for radius (<5).
		917
		918	=cut
345		919
346	sub blur($$;$) {	920	sub blur($$;$) {
347	my $img = pop;	921	my $img = pop;
348	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	922	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
349	}	923	}
350		924
351	sub contrast($$;$$;$) {
352	my $img = pop;
353	my ($r, $g, $b, $a) = @_;
354
355	($g, $b) = ($r, $r) if @_ < 4;
356	$a = 1 if @_ < 5;
357
358	$img = $img->clone;
359	$img->contrast ($r, $g, $b, $a);
360	$img
361	}
362
363	sub brightness($$;$$;$) {
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	925	=back
376		926
		927	=head2 OTHER STUFF
		928
		929	Anything that didn't fit any of the other categories, even after applying
		930	force and closing our eyes.
		931
		932	=over 4
		933
		934	=item keep { ... }
		935
		936	This operator takes a code block as argument, that is, one or more
		937	statements enclosed by braces.
		938
		939	The trick is that this code block is only evaluated when the outcome
		940	changes - on other calls the C<keep> simply returns the image it computed
		941	previously (yes, it should only be used with images). Or in other words,
		942	C<keep> I<caches> the result of the code block so it doesn't need to be
		943	computed again.
		944
		945	This can be extremely useful to avoid redoing slow operations - for
		946	example, if your background expression takes the root background, blurs it
		947	and then root-aligns it it would have to blur the root background on every
		948	window move or resize.
		949
		950	Another example is C<load>, which can be quite slow.
		951
		952	In fact, urxvt itself encloses the whole expression in some kind of
		953	C<keep> block so it only is reevaluated as required.
		954
		955	Putting the blur into a C<keep> block will make sure the blur is only done
		956	once, while the C<rootalign> is still done each time the window moves.
		957
		958	rootalign keep { blur 10, root }
		959
		960	This leaves the question of how to force reevaluation of the block,
		961	in case the root background changes: If expression inside the block
		962	is sensitive to some event (root background changes, window geometry
		963	changes), then it will be reevaluated automatically as needed.
		964
		965	=cut
		966
		967	sub keep(&) {
		968	my $id = $_[0]+0;
		969
		970	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		971
		972	unless ($frame->[FR_CACHE]) {
		973	$frame->[FR_CACHE] = [ $_[0]() ];
		974
		975	my $self = $self;
		976	my $frame = $frame;
		977	Scalar::Util::weaken $frame;
		978	$self->compile_frame ($frame, sub {
		979	# clear this frame cache, also for all parents
		980	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		981	undef $frame->[FR_CACHE];
		982	}
		983
		984	$self->recalculate;
		985	});
		986	};
		987
		988	# in scalar context we always return the first original result, which
		989	# is not quite how perl works.
		990	wantarray
		991	? @{ $frame->[FR_CACHE] }
		992	: $frame->[FR_CACHE][0]
		993	}
		994
		995	# sub keep_clear() {
		996	# delete $self->{frame_cache};
		997	# }
		998
		999	=back
		1000
377	=cut	1001	=cut
378		1002
379	}	1003	}
380		1004
381	sub parse_expr {	1005	sub parse_expr {
382	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	1006	my $expr = eval
		1007	"sub {\n"
		1008	. "package urxvt::bgdsl;\n"
		1009	. "#line 0 'background expression'\n"
		1010	. "$_[0]\n"
		1011	. "}";
383	die if $@;	1012	die if $@;
384	$expr	1013	$expr
385	}	1014	}
386		1015
387	# compiles a parsed expression	1016	# compiles a parsed expression
388	sub set_expr {	1017	sub set_expr {
389	my ($self, $expr) = @_;	1018	my ($self, $expr) = @_;
390		1019
		1020	$self->{root} = []; # the outermost frame
391	$self->{expr} = $expr;	1021	$self->{expr} = $expr;
392	$self->recalculate;	1022	$self->recalculate;
		1023	}
		1024
		1025	# takes a hash of sensitivity indicators and installs watchers
		1026	sub compile_frame {
		1027	my ($self, $frame, $cb) = @_;
		1028
		1029	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		1030	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		1031
		1032	# don't keep stuff alive
		1033	Scalar::Util::weaken $state;
		1034
		1035	if ($again->{nested}) {
		1036	$state->{nested} = 1;
		1037	} else {
		1038	delete $state->{nested};
		1039	}
		1040
		1041	if (my $interval = $again->{time}) {
		1042	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		1043	if $state->{time}[0] != $interval;
		1044
		1045	# callback might have changed, although we could just rule that out
		1046	$state->{time}[1]->cb (sub {
		1047	++$state->{counter};
		1048	$cb->();
		1049	});
		1050	} else {
		1051	delete $state->{time};
		1052	}
		1053
		1054	if ($again->{position}) {
		1055	$state->{position} = $self->on (position_change => $cb);
		1056	} else {
		1057	delete $state->{position};
		1058	}
		1059
		1060	if ($again->{size}) {
		1061	$state->{size} = $self->on (size_change => $cb);
		1062	} else {
		1063	delete $state->{size};
		1064	}
		1065
		1066	if ($again->{rootpmap}) {
		1067	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		1068	} else {
		1069	delete $state->{rootpmap};
		1070	}
393	}	1071	}
394		1072
395	# evaluate the current bg expression	1073	# evaluate the current bg expression
396	sub recalculate {	1074	sub recalculate {
397	my ($arg_self) = @_;	1075	my ($arg_self) = @_;
…		…
407		1085
408	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1086	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
409		1087
410	# set environment to evaluate user expression	1088	# set environment to evaluate user expression
411		1089
412	local $self = $arg_self;	1090	local $self = $arg_self;
413		1091	local $HOME = $ENV{HOME};
414	local $old = $self->{state};	1092	local $frame = $self->{root};
415	local $new = my $state = $self->{state} = {};
416		1093
417	($x, $y, $w, $h) =
418	$self->background_geometry ($self->{border});	1094	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
419		1095
420	# evaluate user expression	1096	# evaluate user expression
421		1097
422	my $img = eval { $self->{expr}->() };	1098	my @img = eval { $self->{expr}->() };
423	warn $@ if $@;#d#	1099	die $@ if $@;
		1100	die "background-expr did not return anything.\n" unless @img;
		1101	die "background-expr: expected image(s), got something else.\n"
424	die if !UNIVERSAL::isa $img, "urxvt::img";	1102	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
		1103
		1104	my $img = urxvt::bgdsl::merge @img;
		1105
		1106	$frame->[FR_AGAIN]{size} = 1
		1107	if $img->repeat_mode != urxvt::RepeatNormal;
425		1108
426	# if the expression is sensitive to external events, prepare reevaluation then	1109	# if the expression is sensitive to external events, prepare reevaluation then
427		1110	$self->compile_frame ($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	$self->disable ("rootpmap_change");
459	}
460		1111
461	# clear stuff we no longer need	1112	# clear stuff we no longer need
462		1113
463	%$old = ();	1114	# unless (%{ $frame->[FR_STATE] }) {
464
465	unless ($repeat) {
466	delete $self->{state};	1115	# delete $self->{state};
467	delete $self->{expr};	1116	# delete $self->{expr};
468	}	1117	# }
469		1118
470	# prepare and set background pixmap	1119	# set background pixmap
471
472	$img = $img->sub_rect (0, 0, $w, $h)
473	if $img->w != $w \|\| $img->h != $h;
474		1120
475	$self->set_background ($img, $self->{border});	1121	$self->set_background ($img, $self->{border});
476	$self->scr_recolour (0);	1122	$self->scr_recolour (0);
477	$self->want_refresh;	1123	$self->want_refresh;
478	}	1124	}
479		1125
480	sub on_start {	1126	sub on_start {
481	my ($self) = @_;	1127	my ($self) = @_;
482		1128
483	my $expr = $self->x_resource ("background.expr")	1129	my $expr = $self->x_resource ("%.expr")
484	or return;	1130	or return;
485		1131
		1132	$self->has_render
		1133	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1134
486	$self->set_expr (parse_expr $expr);	1135	$self->set_expr (parse_expr $expr);
487	$self->{border} = $self->x_resource_boolean ("background.border");	1136	$self->{border} = $self->x_resource_boolean ("%.border");
		1137
		1138	$MIN_INTERVAL = $self->x_resource ("%.interval");
488		1139
489	()	1140	()
490	}	1141	}
491		1142

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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 1.76 by root, Tue Aug 14 23:57:07 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 1.76 by root, Tue Aug 14 23:57:07 2012 UTC