[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 1.68 by root, Sun Jul 1 21:47:07 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
13	=head2 DESCRIPTION	17	=head1 DESCRIPTION
14		18
		19	This extension manages the terminal background by creating a picture that
		20	is behind the text, replacing the normal background colour.
		21
		22	It does so by evaluating a Perl expression that I<calculates> the image on
		23	the fly, for example, by grabbing the root background or loading a file.
		24
		25	While the full power of Perl is available, the operators have been design
		26	to be as simple as possible.
		27
		28	For example, to load an image and scale it to the window size, you would
		29	use:
		30
		31	urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
		32
		33	Or specified as a X resource:
		34
		35	URxvt.background-expr: scale keep { load "/path/to/mybg.png" }
		36
		37	=head1 THEORY OF OPERATION
		38
		39	At startup, just before the window is mapped for the first time, the
		40	expression is evaluated and must yield an image. The image is then
		41	extended as necessary to cover the whole terminal window, and is set as a
		42	background pixmap.
		43
		44	If the image contains an alpha channel, then it will be used as-is in
		45	visuals that support alpha channels (for example, for a compositing
		46	manager). In other visuals, the terminal background colour will be used to
		47	replace any transparency.
		48
		49	When the expression relies, directly or indirectly, on the window size,
		50	position, the root pixmap, or a timer, then it will be remembered. If not,
		51	then it will be removed.
		52
		53	If any of the parameters that the expression relies on changes (when the
		54	window is moved or resized, its position or size changes; when the root
		55	pixmap is replaced by another one the root background changes; or when the
		56	timer elapses), then the expression will be evaluated again.
		57
		58	For example, an expression such as C<scale keep { load "$HOME/mybg.png"
		59	}> scales the image to the window size, so it relies on the window size
		60	and will be reevaluated each time it is changed, but not when it moves for
		61	example. That ensures that the picture always fills the terminal, even
		62	after its size changes.
		63
		64	=head2 EXPRESSIONS
		65
		66	Expressions are normal Perl expressions, in fact, they are Perl blocks -
		67	which means you could use multiple lines and statements:
		68
		69	scale keep {
		70	again 3600;
		71	if (localtime now)[6]) {
		72	return load "$HOME/weekday.png";
		73	} else {
		74	return load "$HOME/sunday.png";
		75	}
		76	}
		77
		78	This inner expression is evaluated once per hour (and whenever the
		79	temrinal window is resized). It sets F<sunday.png> as background on
		80	Sundays, and F<weekday.png> on all other days.
		81
		82	Fortunately, we expect that most expressions will be much simpler, with
		83	little Perl knowledge needed.
		84
		85	Basically, you always start with a function that "generates" an image
		86	object, such as C<load>, which loads an image from disk, or C<root>, which
		87	returns the root window background image:
		88
		89	load "$HOME/mypic.png"
		90
		91	The path is usually specified as a quoted string (the exact rules can be
		92	found in the L<perlop> manpage). The F<$HOME> at the beginning of the
		93	string is expanded to the home directory.
		94
		95	Then you prepend one or more modifiers or filtering expressions, such as
		96	C<scale>:
		97
		98	scale load "$HOME/mypic.png"
		99
		100	Just like a mathematical expression with functions, you should read these
		101	expressions from right to left, as the C<load> is evaluated first, and
		102	its result becomes the argument to the C<scale> function.
		103
		104	Many operators also allow some parameters preceding the input image
		105	that modify its behaviour. For example, C<scale> without any additional
		106	arguments scales the image to size of the terminal window. If you specify
		107	an additional argument, it uses it as a scale factor (multiply by 100 to
		108	get a percentage):
		109
		110	scale 2, load "$HOME/mypic.png"
		111
		112	This enlarges the image by a factor of 2 (200%). As you can see, C<scale>
		113	has now two arguments, the C<200> and the C<load> expression, while
		114	C<load> only has one argument. Arguments are separated from each other by
		115	commas.
		116
		117	Scale also accepts two arguments, which are then separate factors for both
		118	horizontal and vertical dimensions. For example, this halves the image
		119	width and doubles the image height:
		120
		121	scale 0.5, 2, load "$HOME/mypic.png"
		122
		123	IF you try out these expressions, you might suffer from some sluggishness,
		124	because each time the terminal is resized, it loads the PNG image agin
		125	and scales it. Scaling is usually fast (and unavoidable), but loading the
		126	image can be quite time consuming. This is where C<keep> comes in handy:
		127
		128	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		129
		130	The C<keep> operator executes all the statements inside the braces only
		131	once, or when it thinks the outcome might change. In other cases it
		132	returns the last value computed by the brace block.
		133
		134	This means that the C<load> is only executed once, which makes it much
		135	faster, but also means that more memory is being used, because the loaded
		136	image must be kept in memory at all times. In this expression, the
		137	trade-off is likely worth it.
		138
		139	But back to effects: Other effects than scaling are also readily
		140	available, for example, you can tile the image to fill the whole window,
		141	instead of resizing it:
		142
		143	tile keep { load "$HOME/mypic.png" }
		144
		145	In fact, images returned by C<load> are in C<tile> mode by default, so the
		146	C<tile> operator is kind of superfluous.
		147
		148	Another common effect is to mirror the image, so that the same edges
		149	touch:
		150
		151	mirror keep { load "$HOME/mypic.png" }
		152
		153	Another common background expression is:
		154
		155	rootalign root
		156
		157	This one first takes a snapshot of the screen background image, and then
		158	moves it to the upper left corner of the screen (as opposed to the upper
		159	left corner of the terminal window)- the result is pseudo-transparency:
		160	the image seems to be static while the window is moved around.
		161
		162	=head2 CACHING AND SENSITIVITY
		163
		164	Since some operations (such as C<load> and C<blur>) can take a long time,
		165	caching results can be very important for a smooth operation. Caching can
		166	also be useful to reduce memory usage, though, for example, when an image
		167	is cached by C<load>, it could be shared by multiple terminal windows
		168	running inside urxvtd.
		169
		170	=head3 C<keep { ... }> caching
		171
		172	The most important way to cache expensive operations is to use C<keep {
		173	... }>. The C<keep> operator takes a block of multiple statements enclosed
		174	by C<{}> and keeps the return value in memory.
		175
		176	An expression can be "sensitive" to various external events, such as
		177	scaling or moving the window, root background changes and timers. Simply
		178	using an expression (such as C<scale> without parameters) that depends on
		179	certain changing values (called "variables"), or using those variables
		180	directly, will make an expression sensitive to these events - for example,
		181	using C<scale> or C<TW> will make the expression sensitive to the terminal
		182	size, and thus to resizing events.
		183
		184	When such an event happens, C<keep> will automatically trigger a
		185	reevaluation of the whole expression with the new value of the expression.
		186
		187	C<keep> is most useful for expensive operations, such as C<blur>:
		188
		189	rootalign keep { blur 20, root }
		190
		191	This makes a blurred copy of the root background once, and on subsequent
		192	calls, just root-aligns it. Since C<blur> is usually quite slow and
		193	C<rootalign> is quite fast, this trades extra memory (for the cached
		194	blurred pixmap) with speed (blur only needs to be redone when root
		195	changes).
		196
		197	=head3 C<load> caching
		198
		199	The C<load> operator itself does not keep images in memory, but as long as
		200	the image is still in memory, C<load> will use the in-memory image instead
		201	of loading it freshly from disk.
		202
		203	That means that this expression:
		204
		205	keep { load "$HOME/path..." }
		206
		207	Not only caches the image in memory, other terminal instances that try to
		208	C<load> it can reuse that in-memory copy.
		209
15	=head2 REFERENCE	210	=head1 REFERENCE
16		211
17	=cut	212	=head2 COMMAND LINE SWITCHES
18		213
19	our $EXPR;	214	=over 4
20	#$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	#$EXPR = 'blur move (root, -x, -y), 5, 5'
30	#resize load "/root/pix/das_fette_schwein.jpg", w, h
31		215
32	our ($self, $old, $new);	216	=item --background-expr perl-expression
		217
		218	Specifies the Perl expression to evaluate.
		219
		220	=item --background-border
		221
		222	By default, the expression creates an image that fills the full window,
		223	overwriting borders and any other areas, such as the scrollbar.
		224
		225	Specifying this flag changes the behaviour, so that the image only
		226	replaces the background of the character area.
		227
		228	=item --background-interval seconds
		229
		230	Since some operations in the underlying XRender extension can effectively
		231	freeze your X-server for prolonged time, this extension enforces a minimum
		232	time between updates, which is normally about 0.1 seconds.
		233
		234	If you want to do updates more often, you can decrease this safety
		235	interval with this switch.
		236
		237	=back
		238
		239	=cut
		240
		241	our %_IMG_CACHE;
		242	our $HOME;
		243	our ($self, $frame);
33	our ($x, $y, $w, $h);	244	our ($x, $y, $w, $h);
34		245
35	# enforce at least this interval between updates	246	# enforce at least this interval between updates
36	our $MIN_INTERVAL = 1/100;	247	our $MIN_INTERVAL = 6/59.951;
37		248
38	{	249	{
39	package urxvt::bgdsl; # background language	250	package urxvt::bgdsl; # background language
		251
		252	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
		253	sub FR_CACHE () { 1 } # cached values
		254	sub FR_AGAIN () { 2 } # what this expr is sensitive to
		255	sub FR_STATE () { 3 } # watchers etc.
		256
		257	use List::Util qw(min max sum shuffle);
40		258
41	=head2 PROVIDERS/GENERATORS	259	=head2 PROVIDERS/GENERATORS
42		260
43	These functions provide an image, by loading it from disk, grabbing it	261	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	262	from the root screen or by simply generating it. They are used as starting
49	=item load $path	267	=item load $path
50		268
51	Loads the image at the given C<$path>. The image is set to plane tiling	269	Loads the image at the given C<$path>. The image is set to plane tiling
52	mode.	270	mode.
53		271
54	Loaded images will be cached for one cycle.	272	If the image is already in memory (e.g. because another terminal instance
		273	uses it), then the in-memory copy us returned instead.
55		274
		275	=item load_uc $path
		276
		277	Load uncached - same as load, but does not cache the image, which means it
		278	is I<always> loaded from the filesystem again.
		279
56	=cut	280	=cut
		281
		282	sub load_uc($) {
		283	$self->new_img_from_file ($path)
		284	}
57		285
58	sub load($) {	286	sub load($) {
59	my ($path) = @_;	287	my ($path) = @_;
60		288
61	$new->{load}{$path} = $old->{load}{$path} \|\| $self->new_img_from_file ($path);	289	$_IMG_CACHE{$path} \|\| do {
		290	my $img = load_uc $path;
		291	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		292	$img
		293	}
62	}	294	}
63		295
64	=item root	296	=item root
65		297
66	Returns the root window pixmap, that is, hopefully, the background image	298	Returns the root window pixmap, that is, hopefully, the background image
67	of your screen. The image is set to extend mode.	299	of your screen.
68		300
69	This function makes your expression root sensitive, that means it will be	301	This function makes your expression root sensitive, that means it will be
70	reevaluated when the bg image changes.	302	reevaluated when the bg image changes.
71		303
72	=cut	304	=cut
73		305
74	sub root() {	306	sub root() {
75	$new->{rootpmap_sensitive} = 1;	307	$frame->[FR_AGAIN]{rootpmap} = 1;
76	die "root op not supported, exg, we need you";	308	$self->new_img_from_root
77	}	309	}
78		310
79	=item solid $colour	311	=item solid $colour
80		312
81	=item solid $width, $height, $colour	313	=item solid $width, $height, $colour
82		314
83	Creates a new image and completely fills it with the given colour. The	315	Creates a new image and completely fills it with the given colour. The
84	image is set to tiling mode.	316	image is set to tiling mode.
85		317
86	If <$width> and C<$height> are omitted, it creates a 1x1 image, which is	318	If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
87	useful for solid backgrounds or for use in filtering effects.	319	useful for solid backgrounds or for use in filtering effects.
88		320
89	=cut	321	=cut
90		322
91	sub solid($$;$) {	323	sub solid($;$$) {
92	my $colour = pop;	324	my $colour = pop;
93		325
94	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	326	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
95	$img->fill ($colour);	327	$img->fill ($colour);
96	$img	328	$img
97	}	329	}
98		330
99	=back	331	=item clone $img
100		332
101	=head2 VARIABLES	333	Returns an exact copy of the image. This is useful if you want to have
		334	multiple copies of the same image to apply different effects to.
102		335
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	336	=cut
144		337
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} = $_[0];
178	}
179
180	sub counter($) {	338	sub clone($) {
181	$new->{again} = $_[0];	339	$_[0]->clone
182	$self->{counter} + 0
183	}	340	}
184		341
185	=back	342	=item merge $img ...
		343
		344	Takes any number of images and merges them together, creating a single
		345	image containing them all. The tiling mode of the first image is used as
		346	the tiling mode of the resulting image.
		347
		348	This function is called automatically when an expression returns multiple
		349	images.
		350
		351	=cut
		352
		353	sub merge(@) {
		354	return $_[0] unless $#_;
		355
		356	# rather annoyingly clumsy, but optimisation is for another time
		357
		358	my $x0 = +1e9;
		359	my $y0 = +1e9;
		360	my $x1 = -1e9;
		361	my $y1 = -1e9;
		362
		363	for (@_) {
		364	my ($x, $y, $w, $h) = $_->geometry;
		365
		366	$x0 = $x if $x0 > $x;
		367	$y0 = $y if $y0 > $y;
		368
		369	$x += $w;
		370	$y += $h;
		371
		372	$x1 = $x if $x1 < $x;
		373	$y1 = $y if $y1 < $y;
		374	}
		375
		376	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		377	$base->repeat_mode ($_[0]->repeat_mode);
		378	$base->fill ([0, 0, 0, 0]);
		379
		380	$base->draw ($_)
		381	for @_;
		382
		383	$base
		384	}
186		385
187	=head2 TILING MODES	386	=head2 TILING MODES
188		387
189	The following operators modify the tiling mode of an image, that is, the	388	The following operators modify the tiling mode of an image, that is, the
190	way that pixels outside the image area are painted when the image is used.	389	way that pixels outside the image area are painted when the image is used.
…		…
193		392
194	=item tile $img	393	=item tile $img
195		394
196	Tiles the whole plane with the image and returns this new image - or in	395	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.	396	other words, it returns a copy of the image in plane tiling mode.
		397
		398	Example: load an image and tile it over the background, without
		399	resizing. The C<tile> call is superfluous because C<load> already defaults
		400	to tiling mode.
		401
		402	tile load "mybg.png"
198		403
199	=item mirror $img	404	=item mirror $img
200		405
201	Similar to tile, but reflects the image each time it uses a new copy, so	406	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	407	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	408	edges and so on (with normal tiling, left edges always touch right edges
204	and top always touch bottom edges).	409	and top always touch bottom edges).
205		410
		411	Example: load an image and mirror it over the background, avoiding sharp
		412	edges at the image borders at the expense of mirroring the image itself
		413
		414	mirror load "mybg.png"
		415
206	=item pad $img	416	=item pad $img
207		417
208	Takes an image and modifies it so that all pixels outside the image area	418	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	419	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	420	image over another image or the background colour while leaving all
211	background pixels outside the image unchanged.	421	background pixels outside the image unchanged.
212		422
		423	Example: load an image and display it in the upper left corner. The rest
		424	of the space is left "empty" (transparent or whatever your compositor does
		425	in alpha mode, else background colour).
		426
		427	pad load "mybg.png"
		428
213	=item extend $img	429	=item extend $img
214		430
215	Extends the image over the whole plane, using the closest pixel in the	431	Extends the image over the whole plane, using the closest pixel in the
216	area outside the image. This mode is mostly useful when you more complex	432	area outside the image. This mode is mostly useful when you use more complex
217	filtering operations and want the pixels outside the image to have the	433	filtering operations and want the pixels outside the image to have the
218	same values as the pixels near the edge.	434	same values as the pixels near the edge.
		435
		436	Example: just for curiosity, how does this pixel extension stuff work?
		437
		438	extend move 50, 50, load "mybg.png"
219		439
220	=cut	440	=cut
221		441
222	sub pad($) {	442	sub pad($) {
223	my $img = $_[0]->clone;	443	my $img = $_[0]->clone;
…		…
243	$img	463	$img
244	}	464	}
245		465
246	=back	466	=back
247		467
248	=head2 PIXEL OPERATORS	468	=head2 VARIABLE VALUES
249		469
250	The following operators modify the image pixels in various ways.	470	The following functions provide variable data such as the terminal window
		471	dimensions. They are not (Perl-) variables, they just return stuff that
		472	varies. Most of them make your expression sensitive to some events, for
		473	example using C<TW> (terminal width) means your expression is evaluated
		474	again when the terminal is resized.
251		475
252	=over 4	476	=over 4
253		477
254	=item clone $img	478	=item TX
255		479
256	Returns an exact copy of the image.	480	=item TY
257		481
258	=cut	482	Return the X and Y coordinates of the terminal window (the terminal
		483	window is the full window by default, and the character area only when in
		484	border-respect mode).
259		485
		486	Using these functions make your expression sensitive to window moves.
		487
		488	These functions are mainly useful to align images to the root window.
		489
		490	Example: load an image and align it so it looks as if anchored to the
		491	background (that's exactly what C<rootalign> does btw.):
		492
		493	move -TX, -TY, keep { load "mybg.png" }
		494
		495	=item TW
		496
		497	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		498	terminal window is the full window by default, and the character area only
		499	when in border-respect mode).
		500
		501	Using these functions make your expression sensitive to window resizes.
		502
		503	These functions are mainly useful to scale images, or to clip images to
		504	the window size to conserve memory.
		505
		506	Example: take the screen background, clip it to the window size, blur it a
		507	bit, align it to the window position and use it as background.
		508
		509	clip move -TX, -TY, keep { blur 5, root }
		510
		511	=cut
		512
		513	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
		514	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
		515	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
		516	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
		517
		518	=item now
		519
		520	Returns the current time as (fractional) seconds since the epoch.
		521
		522	Using this expression does I<not> make your expression sensitive to time,
		523	but the next two functions do.
		524
		525	=item again $seconds
		526
		527	When this function is used the expression will be reevaluated again in
		528	C<$seconds> seconds.
		529
		530	Example: load some image and rotate it according to the time of day (as if it were
		531	the hour pointer of a clock). Update this image every minute.
		532
		533	again 60;
		534	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
		535
		536	=item counter $seconds
		537
		538	Like C<again>, but also returns an increasing counter value, starting at
		539	0, which might be useful for some simple animation effects.
		540
		541	=cut
		542
		543	sub now() { urxvt::NOW }
		544
		545	sub again($) {
		546	$frame->[FR_AGAIN]{time} = $_[0];
		547	}
		548
260	sub clone($) {	549	sub counter($) {
261	$_[0]->clone	550	$frame->[FR_AGAIN]{time} = $_[0];
		551	$frame->[FR_STATE]{counter} + 0
262	}	552	}
		553
		554	=back
		555
		556	=head2 SHAPE CHANGING OPERATORS
		557
		558	The following operators modify the shape, size or position of the image.
		559
		560	=over 4
263		561
264	=item clip $img	562	=item clip $img
265		563
266	=item clip $width, $height, $img	564	=item clip $width, $height, $img
267		565
…		…
278	assumed.	576	assumed.
279		577
280	Example: load an image, blur it, and clip it to the window size to save	578	Example: load an image, blur it, and clip it to the window size to save
281	memory.	579	memory.
282		580
283	clip blur 10, load "mybg.png"	581	clip keep { blur 10, load "mybg.png" }
284		582
285	=cut	583	=cut
286		584
287	sub clip($;$$;$$) {	585	sub clip($;$$;$$) {
288	my $img = pop;	586	my $img = pop;
…		…
291	$img->sub_rect ($_[0], $_[1], $w, $h)	589	$img->sub_rect ($_[0], $_[1], $w, $h)
292	}	590	}
293		591
294	=item scale $img	592	=item scale $img
295		593
296	=item scale $size_percent, $img	594	=item scale $size_factor, $img
297		595
298	=item scale $width_percent, $height_percent, $img	596	=item scale $width_factor, $height_factor, $img
299		597
300	Scales the image by the given percentages in horizontal	598	Scales the image by the given factors in horizontal
301	(C<$width_percent>) and vertical (C<$height_percent>) direction.	599	(C<$width>) and vertical (C<$height>) direction.
302		600
303	If only one percentage is give, it is used for both directions.	601	If only one factor is give, it is used for both directions.
304		602
305	If no percentages are given, scales the image to the window size without	603	If no factors are given, scales the image to the window size without
306	keeping aspect.	604	keeping aspect.
307		605
308	=item resize $width, $height, $img	606	=item resize $width, $height, $img
309		607
310	Resizes the image to exactly C<$width> times C<$height> pixels.	608	Resizes the image to exactly C<$width> times C<$height> pixels.
311		609
312	=cut	610	=item fit $img
313		611
314	#TODO: maximise, maximise_fill?	612	=item fit $width, $height, $img
		613
		614	Fits the image into the given C<$width> and C<$height> without changing
		615	aspect, or the terminal size. That means it will be shrunk or grown until
		616	the whole image fits into the given area, possibly leaving borders.
		617
		618	=item cover $img
		619
		620	=item cover $width, $height, $img
		621
		622	Similar to C<fit>, but shrinks or grows until all of the area is covered
		623	by the image, so instead of potentially leaving borders, it will cut off
		624	image data that doesn't fit.
		625
		626	=cut
315		627
316	sub scale($;$;$) {	628	sub scale($;$;$) {
317	my $img = pop;	629	my $img = pop;
318		630
319	@_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01)	631	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
320	: @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01)	632	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
321	: $img->scale (TW, TH)	633	: $img->scale (TW, TH)
322	}	634	}
323		635
324	sub resize($$$) {	636	sub resize($$$) {
325	my $img = pop;	637	my $img = pop;
326	$img->scale ($_[0], $_[1])	638	$img->scale ($_[0], $_[1])
327	}	639	}
		640
		641	sub fit($;$$) {
		642	my $img = pop;
		643	my $w = ($_[0] \|\| TW) / $img->w;
		644	my $h = ($_[1] \|\| TH) / $img->h;
		645	scale +(min $w, $h), $img
		646	}
		647
		648	sub cover($;$$) {
		649	my $img = pop;
		650	my $w = ($_[0] \|\| TW) / $img->w;
		651	my $h = ($_[1] \|\| TH) / $img->h;
		652	scale +(max $w, $h), $img
		653	}
		654
		655	=item move $dx, $dy, $img
		656
		657	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
		658	the vertical.
		659
		660	Example: move the image right by 20 pixels and down by 30.
		661
		662	move 20, 30, ...
		663
		664	=item align $xalign, $yalign, $img
		665
		666	Aligns the image according to a factor - C<0> means the image is moved to
		667	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		668	exactly centered and C<1> means it touches the right or bottom edge.
		669
		670	Example: remove any visible border around an image, center it vertically but move
		671	it to the right hand side.
		672
		673	align 1, 0.5, pad $img
		674
		675	=item center $img
		676
		677	=item center $width, $height, $img
		678
		679	Centers the image, i.e. the center of the image is moved to the center of
		680	the terminal window (or the box specified by C<$width> and C<$height> if
		681	given).
		682
		683	Example: load an image and center it.
		684
		685	center keep { pad load "mybg.png" }
		686
		687	=item rootalign $img
		688
		689	Moves the image so that it appears glued to the screen as opposed to the
		690	window. This gives the illusion of a larger area behind the window. It is
		691	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
		692	top left of the screen.
		693
		694	Example: load a background image, put it in mirror mode and root align it.
		695
		696	rootalign keep { mirror load "mybg.png" }
		697
		698	Example: take the screen background and align it, giving the illusion of
		699	transparency as long as the window isn't in front of other windows.
		700
		701	rootalign root
		702
		703	=cut
328		704
329	sub move($$;$) {	705	sub move($$;$) {
330	my $img = pop->clone;	706	my $img = pop->clone;
331	$img->move ($_[0], $_[1]);	707	$img->move ($_[0], $_[1]);
332	$img	708	$img
333	}	709	}
334		710
		711	sub align($;$$) {
		712	my $img = pop;
		713
		714	move $_[0] * (TW - $img->w),
		715	$_[1] * (TH - $img->h),
		716	$img
		717	}
		718
		719	sub center($;$$) {
		720	my $img = pop;
		721	my $w = $_[0] \|\| TW;
		722	my $h = $_[1] \|\| TH;
		723
		724	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		725	}
		726
		727	sub rootalign($) {
		728	move -TX, -TY, $_[0]
		729	}
		730
		731	=item rotate $center_x, $center_y, $degrees, $img
		732
		733	Rotates the image clockwise by C<$degrees> degrees, around the point at
		734	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		735
		736	Example: rotate the image by 90 degrees around it's center.
		737
		738	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		739
		740	=cut
		741
335	sub rotate($$$$$$) {	742	sub rotate($$$$) {
336	my $img = pop;	743	my $img = pop;
337	$img->rotate (	744	$img->rotate (
338	$_[0],	745	$_[0] * ($img->w + $img->x),
339	$_[1],	746	$_[1] * ($img->h + $img->y),
340	$_[2] * $img->w * .01,
341	$_[3] * $img->h * .01,
342	$_[4] * (3.14159265 / 180),	747	$_[2] * (3.14159265 / 180),
343	)	748	)
344	}	749	}
		750
		751	=back
		752
		753	=head2 COLOUR MODIFICATIONS
		754
		755	The following operators change the pixels of the image.
		756
		757	=over 4
		758
		759	=item contrast $factor, $img
		760
		761	=item contrast $r, $g, $b, $img
		762
		763	=item contrast $r, $g, $b, $a, $img
		764
		765	Adjusts the I<contrast> of an image.
		766
		767	The first form applies a single C<$factor> to red, green and blue, the
		768	second form applies separate factors to each colour channel, and the last
		769	form includes the alpha channel.
		770
		771	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		772	contrast.
		773
		774	Due to limitations in the underlying XRender extension, lowering contrast
		775	also reduces brightness, while increasing contrast currently also
		776	increases brightness.
		777
		778	=item brightness $bias, $img
		779
		780	=item brightness $r, $g, $b, $img
		781
		782	=item brightness $r, $g, $b, $a, $img
		783
		784	Adjusts the brightness of an image.
		785
		786	The first form applies a single C<$bias> to red, green and blue, the
		787	second form applies separate biases to each colour channel, and the last
		788	form includes the alpha channel.
		789
		790	Values less than 0 reduce brightness, while values larger than 0 increase
		791	it. Useful range is from -1 to 1 - the former results in a black, the
		792	latter in a white picture.
		793
		794	Due to idiosyncrasies in the underlying XRender extension, biases less
		795	than zero can be I<very> slow.
		796
		797	=cut
		798
		799	sub contrast($$;$$;$) {
		800	my $img = pop;
		801	my ($r, $g, $b, $a) = @_;
		802
		803	($g, $b) = ($r, $r) if @_ < 3;
		804	$a = 1 if @_ < 4;
		805
		806	$img = $img->clone;
		807	$img->contrast ($r, $g, $b, $a);
		808	$img
		809	}
		810
		811	sub brightness($$;$$;$) {
		812	my $img = pop;
		813	my ($r, $g, $b, $a) = @_;
		814
		815	($g, $b) = ($r, $r) if @_ < 3;
		816	$a = 1 if @_ < 4;
		817
		818	$img = $img->clone;
		819	$img->brightness ($r, $g, $b, $a);
		820	$img
		821	}
		822
		823	=item blur $radius, $img
		824
		825	=item blur $radius_horz, $radius_vert, $img
		826
		827	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
		828	can also be specified separately.
		829
		830	Blurring is often I<very> slow, at least compared or other
		831	operators. Larger blur radii are slower than smaller ones, too, so if you
		832	don't want to freeze your screen for long times, start experimenting with
		833	low values for radius (<5).
		834
		835	=cut
345		836
346	sub blur($$;$) {	837	sub blur($$;$) {
347	my $img = pop;	838	my $img = pop;
348	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	839	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
349	}	840	}
350		841
351	sub contrast($$;$$;$) {
352	my $img = pop;
353	my ($r, $g, $b, $a) = @_;
354
355	($g, $b) = ($r, $r) if @_ < 4;
356	$a = 1 if @_ < 5;
357
358	$img = $img->clone;
359	$img->contrast ($r, $g, $b, $a);
360	$img
361	}
362
363	sub brightness($$;$$;$) {
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	842	=back
376		843
		844	=head2 OTHER STUFF
		845
		846	Anything that didn't fit any of the other categories, even after applying
		847	force and closing our eyes.
		848
		849	=over 4
		850
		851	=item keep { ... }
		852
		853	This operator takes a code block as argument, that is, one or more
		854	statements enclosed by braces.
		855
		856	The trick is that this code block is only evaluated when the outcome
		857	changes - on other calls the C<keep> simply returns the image it computed
		858	previously (yes, it should only be used with images). Or in other words,
		859	C<keep> I<caches> the result of the code block so it doesn't need to be
		860	computed again.
		861
		862	This can be extremely useful to avoid redoing slow operations - for
		863	example, if your background expression takes the root background, blurs it
		864	and then root-aligns it it would have to blur the root background on every
		865	window move or resize.
		866
		867	Another example is C<load>, which can be quite slow.
		868
		869	In fact, urxvt itself encloses the whole expression in some kind of
		870	C<keep> block so it only is reevaluated as required.
		871
		872	Putting the blur into a C<keep> block will make sure the blur is only done
		873	once, while the C<rootalign> is still done each time the window moves.
		874
		875	rootlign keep { blur 10, root }
		876
		877	This leaves the question of how to force reevaluation of the block,
		878	in case the root background changes: If expression inside the block
		879	is sensitive to some event (root background changes, window geometry
		880	changes), then it will be reevaluated automatically as needed.
		881
		882	=cut
		883
		884	sub keep(&) {
		885	my $id = $_[0]+0;
		886
		887	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		888
		889	unless ($frame->[FR_CACHE]) {
		890	$frame->[FR_CACHE] = [ $_[0]() ];
		891
		892	my $self = $self;
		893	my $frame = $frame;
		894	Scalar::Util::weaken $frame;
		895	$self->compile_frame ($frame, sub {
		896	# clear this frame cache, also for all parents
		897	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		898	undef $frame->[FR_CACHE];
		899	}
		900
		901	$self->recalculate;
		902	});
		903	};
		904
		905	# in scalar context we always return the first original result, which
		906	# is not quite how perl works.
		907	wantarray
		908	? @{ $frame->[FR_CACHE] }
		909	: $frame->[FR_CACHE][0]
		910	}
		911
		912	# sub keep_clear() {
		913	# delete $self->{frame_cache};
		914	# }
		915
		916	=back
		917
377	=cut	918	=cut
378		919
379	}	920	}
380		921
381	sub parse_expr {	922	sub parse_expr {
382	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	923	my $expr = eval
		924	"sub {\n"
		925	. "package urxvt::bgdsl;\n"
		926	. "#line 0 'background expression'\n"
		927	. "$_[0]\n"
		928	. "}";
383	die if $@;	929	die if $@;
384	$expr	930	$expr
385	}	931	}
386		932
387	# compiles a parsed expression	933	# compiles a parsed expression
388	sub set_expr {	934	sub set_expr {
389	my ($self, $expr) = @_;	935	my ($self, $expr) = @_;
390		936
		937	$self->{root} = [];
391	$self->{expr} = $expr;	938	$self->{expr} = $expr;
392	$self->recalculate;	939	$self->recalculate;
		940	}
		941
		942	# takes a hash of sensitivity indicators and installs watchers
		943	sub compile_frame {
		944	my ($self, $frame, $cb) = @_;
		945
		946	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		947	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		948
		949	# don't keep stuff alive
		950	Scalar::Util::weaken $state;
		951
		952	if ($again->{nested}) {
		953	$state->{nested} = 1;
		954	} else {
		955	delete $state->{nested};
		956	}
		957
		958	if (my $interval = $again->{time}) {
		959	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		960	if $state->{time}[0] != $interval;
		961
		962	# callback might have changed, although we could just rule that out
		963	$state->{time}[1]->cb (sub {
		964	++$state->{counter};
		965	$cb->();
		966	});
		967	} else {
		968	delete $state->{time};
		969	}
		970
		971	if ($again->{position}) {
		972	$state->{position} = $self->on (position_change => $cb);
		973	} else {
		974	delete $state->{position};
		975	}
		976
		977	if ($again->{size}) {
		978	$state->{size} = $self->on (size_change => $cb);
		979	} else {
		980	delete $state->{size};
		981	}
		982
		983	if ($again->{rootpmap}) {
		984	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		985	} else {
		986	delete $state->{rootpmap};
		987	}
393	}	988	}
394		989
395	# evaluate the current bg expression	990	# evaluate the current bg expression
396	sub recalculate {	991	sub recalculate {
397	my ($arg_self) = @_;	992	my ($arg_self) = @_;
…		…
407		1002
408	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1003	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
409		1004
410	# set environment to evaluate user expression	1005	# set environment to evaluate user expression
411		1006
412	local $self = $arg_self;	1007	local $self = $arg_self;
		1008	local $HOME = $ENV{HOME};
		1009	local $frame = [];
413		1010
414	local $old = $self->{state};
415	local $new = my $state = $self->{state} = {};
416
417	($x, $y, $w, $h) =
418	$self->background_geometry ($self->{border});	1011	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
419		1012
420	# evaluate user expression	1013	# evaluate user expression
421		1014
422	my $img = eval { $self->{expr}->() };	1015	my @img = eval { $self->{expr}->() };
423	warn $@ if $@;#d#	1016	die $@ if $@;
		1017	die "background-expr did not return anything.\n" unless @img;
		1018	die "background-expr: expected image(s), got something else.\n"
424	die if !UNIVERSAL::isa $img, "urxvt::img";	1019	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
		1020
		1021	my $img = urxvt::bgdsl::merge @img;
		1022
		1023	$frame->[FR_AGAIN]{size} = 1
		1024	if $img->repeat_mode != urxvt::RepeatNormal;
425		1025
426	# if the expression is sensitive to external events, prepare reevaluation then	1026	# if the expression is sensitive to external events, prepare reevaluation then
427		1027	$self->compile_frame ($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	$self->disable ("rootpmap_change");
459	}
460		1028
461	# clear stuff we no longer need	1029	# clear stuff we no longer need
462		1030
463	%$old = ();	1031	# unless (%{ $frame->[FR_STATE] }) {
464
465	unless ($repeat) {
466	delete $self->{state};	1032	# delete $self->{state};
467	delete $self->{expr};	1033	# delete $self->{expr};
468	}	1034	# }
469		1035
470	# prepare and set background pixmap	1036	# set background pixmap
471
472	$img = $img->sub_rect (0, 0, $w, $h)
473	if $img->w != $w \|\| $img->h != $h;
474		1037
475	$self->set_background ($img, $self->{border});	1038	$self->set_background ($img, $self->{border});
476	$self->scr_recolour (0);	1039	$self->scr_recolour (0);
477	$self->want_refresh;	1040	$self->want_refresh;
478	}	1041	}
479		1042
480	sub on_start {	1043	sub on_start {
481	my ($self) = @_;	1044	my ($self) = @_;
482		1045
483	my $expr = $self->x_resource ("background.expr")	1046	my $expr = $self->x_resource ("%.expr")
484	or return;	1047	or return;
485		1048
		1049	$self->has_render
		1050	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1051
486	$self->set_expr (parse_expr $expr);	1052	$self->set_expr (parse_expr $expr);
487	$self->{border} = $self->x_resource_boolean ("background.border");	1053	$self->{border} = $self->x_resource_boolean ("%.border");
		1054
		1055	$MIN_INTERVAL = $self->x_resource ("%.interval");
488		1056
489	()	1057	()
490	}	1058	}
491		1059

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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 1.68 by root, Sun Jul 1 21:47:07 2012 UTC

Diff Legend

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.33 by root, Thu Jun 7 16:30:58 2012 UTC vs.
Revision 1.68 by root, Sun Jul 1 21:47:07 2012 UTC