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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.35 by root, Fri Jun 8 08:06:38 2012 UTC vs.
Revision 1.75 by root, Fri Aug 10 20:07:11 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
6	#TODO: once, rootalign	7	=head1 NAME
7		8
8	=head1 background - manage terminal background	9	background - manage terminal background
9		10
10	=head2 SYNOPSIS	11	=head1 SYNOPSIS
11		12
12	rxvt -background-expr 'background expression'	13	urxvt --background-expr 'background expression'
13	-background-border	14	--background-border
		15	--background-interval seconds
14		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
15	=head2 DESCRIPTION	41	=head1 DESCRIPTION
16		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
17	=head2 REFERENCE	250	=head1 REFERENCE
18		251
19	=cut	252	=head2 COMMAND LINE SWITCHES
20		253
21	our $EXPR;	254	=over 4
22	#$EXPR = 'move W * 0.1, -H * 0.1, resize W * 0.5, H * 0.5, repeat_none load "opensource.png"';
23	$EXPR = 'move -TX, -TY, load "argb.png"';
24	#$EXPR = '
25	# rotate W, H, 50, 50, counter 1/59.95, repeat_mirror,
26	# clip X, Y, W, H, repeat_mirror,
27	# load "/root/pix/das_fette_schwein.jpg"
28	#';
29	#$EXPR = 'solid "red"';
30	#$EXPR = 'blur root, 10, 10'
31	#$EXPR = 'blur move (root, -x, -y), 5, 5'
32	#resize load "/root/pix/das_fette_schwein.jpg", w, h
33		255
34	our ($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, $frame);
35	our ($x, $y, $w, $h);	284	our ($x, $y, $w, $h);
36		285
37	# enforce at least this interval between updates	286	# enforce at least this interval between updates
38	our $MIN_INTERVAL = 1/100;	287	our $MIN_INTERVAL = 6/59.951;
39		288
40	{	289	{
41	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);
42		298
43	=head2 PROVIDERS/GENERATORS	299	=head2 PROVIDERS/GENERATORS
44		300
45	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
46	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
51	=item load $path	307	=item load $path
52		308
53	Loads the image at the given C<$path>. The image is set to plane tiling	309	Loads the image at the given C<$path>. The image is set to plane tiling
54	mode.	310	mode.
55		311
56	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.
57		314
		315	=item load_uc $path
		316
		317	Load uncached - same as load, but does not cache the image, which means it
		318	is I<always> loaded from the filesystem again, even if another copy of it
		319	is in memory at the time.
		320
58	=cut	321	=cut
		322
		323	sub load_uc($) {
		324	$self->new_img_from_file ($_[0])
		325	}
59		326
60	sub load($) {	327	sub load($) {
61	my ($path) = @_;	328	my ($path) = @_;
62		329
63	$new->{load}{$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	}
64	}	335	}
65		336
66	=item root	337	=item root
67		338
68	Returns the root window pixmap, that is, hopefully, the background image	339	Returns the root window pixmap, that is, hopefully, the background image
69	of your screen. The image is set to extend mode.	340	of your screen.
70		341
71	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
72	reevaluated when the bg image changes.	343	reevaluated when the bg image changes.
73		344
74	=cut	345	=cut
75		346
76	sub root() {	347	sub root() {
77	$new->{rootpmap_sensitive} = 1;	348	$frame->[FR_AGAIN]{rootpmap} = 1;
78	die "root op not supported, exg, we need you";	349	$self->new_img_from_root
79	}	350	}
80		351
81	=item solid $colour	352	=item solid $colour
82		353
83	=item solid $width, $height, $colour	354	=item solid $width, $height, $colour
84		355
85	Creates a new image and completely fills it with the given colour. The	356	Creates a new image and completely fills it with the given colour. The
86	image is set to tiling mode.	357	image is set to tiling mode.
87		358
88	If <$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
89	useful for solid backgrounds or for use in filtering effects.	360	useful for solid backgrounds or for use in filtering effects.
90		361
91	=cut	362	=cut
92		363
93	sub solid($$;$) {	364	sub solid($;$$) {
94	my $colour = pop;	365	my $colour = pop;
95		366
96	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);
97	$img->fill ($colour);	368	$img->fill ($colour);
98	$img	369	$img
99	}	370	}
100		371
101	=back	372	=item clone $img
102		373
103	=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.
104		376
105	The following functions provide variable data such as the terminal
106	window dimensions. Most of them make your expression sensitive to some
107	events, for example using C<TW> (terminal width) means your expression is
108	evaluated again when the terminal is resized.
109
110	=over 4
111
112	=item TX
113
114	=item TY
115
116	Return the X and Y coordinates of the terminal window (the terminal
117	window is the full window by default, and the character area only when in
118	border-respect mode).
119
120	Using these functions make your expression sensitive to window moves.
121
122	These functions are mainly useful to align images to the root window.
123
124	Example: load an image and align it so it looks as if anchored to the
125	background.
126
127	move -TX, -TY, load "mybg.png"
128
129	=item TW
130
131	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
132	terminal window is the full window by default, and the character area only
133	when in border-respect mode).
134
135	Using these functions make your expression sensitive to window resizes.
136
137	These functions are mainly useful to scale images, or to clip images to
138	the window size to conserve memory.
139
140	Example: take the screen background, clip it to the window size, blur it a
141	bit, align it to the window position and use it as background.
142
143	clip move -TX, -TY, blur 5, root
144
145	=cut	377	=cut
146		378
147	sub TX() { $new->{position_sensitive} = 1; $x }
148	sub TY() { $new->{position_sensitive} = 1; $y }
149	sub TW() { $new->{size_sensitive} = 1; $w }
150	sub TH() { $new->{size_sensitive} = 1; $h }
151
152	=item now
153
154	Returns the current time as (fractional) seconds since the epoch.
155
156	Using this expression does I<not> make your expression sensitive to time,
157	but the next two functions do.
158
159	=item again $seconds
160
161	When this function is used the expression will be reevaluated again in
162	C<$seconds> seconds.
163
164	Example: load some image and rotate it according to the time of day (as if it were
165	the hour pointer of a clock). update this image every minute.
166
167	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
168
169	=item counter $seconds
170
171	Like C<again>, but also returns an increasing counter value, starting at
172	0, which might be useful for some simple animation effects.
173
174	=cut
175
176	sub now() { urxvt::NOW }
177
178	sub again($) {
179	$new->{again} = $_[0];
180	}
181
182	sub counter($) {	379	sub clone($) {
183	$new->{again} = $_[0];	380	$_[0]->clone
184	$self->{counter} + 0
185	}	381	}
186		382
187	=back	383	=item merge $img ...
		384
		385	Takes any number of images and merges them together, creating a single
		386	image containing them all. The tiling mode of the first image is used as
		387	the tiling mode of the resulting image.
		388
		389	This function is called automatically when an expression returns multiple
		390	images.
		391
		392	=cut
		393
		394	sub merge(@) {
		395	return $_[0] unless $#_;
		396
		397	# rather annoyingly clumsy, but optimisation is for another time
		398
		399	my $x0 = +1e9;
		400	my $y0 = +1e9;
		401	my $x1 = -1e9;
		402	my $y1 = -1e9;
		403
		404	for (@_) {
		405	my ($x, $y, $w, $h) = $_->geometry;
		406
		407	$x0 = $x if $x0 > $x;
		408	$y0 = $y if $y0 > $y;
		409
		410	$x += $w;
		411	$y += $h;
		412
		413	$x1 = $x if $x1 < $x;
		414	$y1 = $y if $y1 < $y;
		415	}
		416
		417	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		418	$base->repeat_mode ($_[0]->repeat_mode);
		419	$base->fill ([0, 0, 0, 0]);
		420
		421	$base->draw ($_)
		422	for @_;
		423
		424	$base
		425	}
188		426
189	=head2 TILING MODES	427	=head2 TILING MODES
190		428
191	The following operators modify the tiling mode of an image, that is, the	429	The following operators modify the tiling mode of an image, that is, the
192	way that pixels outside the image area are painted when the image is used.	430	way that pixels outside the image area are painted when the image is used.
…		…
209	Similar to tile, but reflects the image each time it uses a new copy, so	447	Similar to tile, but reflects the image each time it uses a new copy, so
210	that top edges always touch top edges, right edges always touch right	448	that top edges always touch top edges, right edges always touch right
211	edges and so on (with normal tiling, left edges always touch right edges	449	edges and so on (with normal tiling, left edges always touch right edges
212	and top always touch bottom edges).	450	and top always touch bottom edges).
213		451
214	Exmaple: load an image and mirror it over the background, avoiding sharp	452	Example: load an image and mirror it over the background, avoiding sharp
215	edges at the image borders at the expense of mirroring the image itself	453	edges at the image borders at the expense of mirroring the image itself
216		454
217	mirror load "mybg.png"	455	mirror load "mybg.png"
218		456
219	=item pad $img	457	=item pad $img
…		…
221	Takes an image and modifies it so that all pixels outside the image area	459	Takes an image and modifies it so that all pixels outside the image area
222	become transparent. This mode is most useful when you want to place an	460	become transparent. This mode is most useful when you want to place an
223	image over another image or the background colour while leaving all	461	image over another image or the background colour while leaving all
224	background pixels outside the image unchanged.	462	background pixels outside the image unchanged.
225		463
226	Example: load an image and display it in the upper left corner. The rets	464	Example: load an image and display it in the upper left corner. The rest
227	of the space is left "empty" (transparent or wahtever your compisotr does	465	of the space is left "empty" (transparent or whatever your compositor does
228	in alpha mode, else background colour).	466	in alpha mode, else background colour).
229		467
230	pad load "mybg.png"	468	pad load "mybg.png"
231		469
232	=item extend $img	470	=item extend $img
233		471
234	Extends the image over the whole plane, using the closest pixel in the	472	Extends the image over the whole plane, using the closest pixel in the
235	area outside the image. This mode is mostly useful when you more complex	473	area outside the image. This mode is mostly useful when you use more complex
236	filtering operations and want the pixels outside the image to have the	474	filtering operations and want the pixels outside the image to have the
237	same values as the pixels near the edge.	475	same values as the pixels near the edge.
238		476
239	Example: just for curiosity, how does this pixel extension stuff work?	477	Example: just for curiosity, how does this pixel extension stuff work?
240		478
…		…
266	$img	504	$img
267	}	505	}
268		506
269	=back	507	=back
270		508
271	=head2 PIXEL OPERATORS	509	=head2 VARIABLE VALUES
272		510
273	The following operators modify the image pixels in various ways.	511	The following functions provide variable data such as the terminal window
		512	dimensions. They are not (Perl-) variables, they just return stuff that
		513	varies. Most of them make your expression sensitive to some events, for
		514	example using C<TW> (terminal width) means your expression is evaluated
		515	again when the terminal is resized.
274		516
275	=over 4	517	=over 4
276		518
277	=item clone $img	519	=item TX
278		520
279	Returns an exact copy of the image.	521	=item TY
280		522
281	=cut	523	Return the X and Y coordinates of the terminal window (the terminal
		524	window is the full window by default, and the character area only when in
		525	border-respect mode).
282		526
		527	Using these functions make your expression sensitive to window moves.
		528
		529	These functions are mainly useful to align images to the root window.
		530
		531	Example: load an image and align it so it looks as if anchored to the
		532	background (that's exactly what C<rootalign> does btw.):
		533
		534	move -TX, -TY, keep { load "mybg.png" }
		535
		536	=item TW
		537
		538	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		539	terminal window is the full window by default, and the character area only
		540	when in border-respect mode).
		541
		542	Using these functions make your expression sensitive to window resizes.
		543
		544	These functions are mainly useful to scale images, or to clip images to
		545	the window size to conserve memory.
		546
		547	Example: take the screen background, clip it to the window size, blur it a
		548	bit, align it to the window position and use it as background.
		549
		550	clip move -TX, -TY, keep { blur 5, root }
		551
		552	=cut
		553
		554	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
		555	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
		556	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
		557	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
		558
		559	=item now
		560
		561	Returns the current time as (fractional) seconds since the epoch.
		562
		563	Using this expression does I<not> make your expression sensitive to time,
		564	but the next two functions do.
		565
		566	=item again $seconds
		567
		568	When this function is used the expression will be reevaluated again in
		569	C<$seconds> seconds.
		570
		571	Example: load some image and rotate it according to the time of day (as if it were
		572	the hour pointer of a clock). Update this image every minute.
		573
		574	again 60;
		575	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
		576
		577	=item counter $seconds
		578
		579	Like C<again>, but also returns an increasing counter value, starting at
		580	0, which might be useful for some simple animation effects.
		581
		582	=cut
		583
		584	sub now() { urxvt::NOW }
		585
		586	sub again($) {
		587	$frame->[FR_AGAIN]{time} = $_[0];
		588	}
		589
283	sub clone($) {	590	sub counter($) {
284	$_[0]->clone	591	$frame->[FR_AGAIN]{time} = $_[0];
		592	$frame->[FR_STATE]{counter} + 0
285	}	593	}
		594
		595	=back
		596
		597	=head2 SHAPE CHANGING OPERATORS
		598
		599	The following operators modify the shape, size or position of the image.
		600
		601	=over 4
286		602
287	=item clip $img	603	=item clip $img
288		604
289	=item clip $width, $height, $img	605	=item clip $width, $height, $img
290		606
…		…
301	assumed.	617	assumed.
302		618
303	Example: load an image, blur it, and clip it to the window size to save	619	Example: load an image, blur it, and clip it to the window size to save
304	memory.	620	memory.
305		621
306	clip blur 10, load "mybg.png"	622	clip keep { blur 10, load "mybg.png" }
307		623
308	=cut	624	=cut
309		625
310	sub clip($;$$;$$) {	626	sub clip($;$$;$$) {
311	my $img = pop;	627	my $img = pop;
…		…
314	$img->sub_rect ($_[0], $_[1], $w, $h)	630	$img->sub_rect ($_[0], $_[1], $w, $h)
315	}	631	}
316		632
317	=item scale $img	633	=item scale $img
318		634
319	=item scale $size_percent, $img	635	=item scale $size_factor, $img
320		636
321	=item scale $width_percent, $height_percent, $img	637	=item scale $width_factor, $height_factor, $img
322		638
323	Scales the image by the given percentages in horizontal	639	Scales the image by the given factors in horizontal
324	(C<$width_percent>) and vertical (C<$height_percent>) direction.	640	(C<$width>) and vertical (C<$height>) direction.
325		641
326	If only one percentage is give, it is used for both directions.	642	If only one factor is give, it is used for both directions.
327		643
328	If no percentages are given, scales the image to the window size without	644	If no factors are given, scales the image to the window size without
329	keeping aspect.	645	keeping aspect.
330		646
331	=item resize $width, $height, $img	647	=item resize $width, $height, $img
332		648
333	Resizes the image to exactly C<$width> times C<$height> pixels.	649	Resizes the image to exactly C<$width> times C<$height> pixels.
334		650
335	=cut	651	=item fit $img
336		652
337	#TODO: maximise, maximise_fill?	653	=item fit $width, $height, $img
		654
		655	Fits the image into the given C<$width> and C<$height> without changing
		656	aspect, or the terminal size. That means it will be shrunk or grown until
		657	the whole image fits into the given area, possibly leaving borders.
		658
		659	=item cover $img
		660
		661	=item cover $width, $height, $img
		662
		663	Similar to C<fit>, but shrinks or grows until all of the area is covered
		664	by the image, so instead of potentially leaving borders, it will cut off
		665	image data that doesn't fit.
		666
		667	=cut
338		668
339	sub scale($;$;$) {	669	sub scale($;$;$) {
340	my $img = pop;	670	my $img = pop;
341		671
342	@_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01)	672	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
343	: @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01)	673	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
344	: $img->scale (TW, TH)	674	: $img->scale (TW, TH)
345	}	675	}
346		676
347	sub resize($$$) {	677	sub resize($$$) {
348	my $img = pop;	678	my $img = pop;
349	$img->scale ($_[0], $_[1])	679	$img->scale ($_[0], $_[1])
350	}	680	}
		681
		682	sub fit($;$$) {
		683	my $img = pop;
		684	my $w = ($_[0] \|\| TW) / $img->w;
		685	my $h = ($_[1] \|\| TH) / $img->h;
		686	scale +(min $w, $h), $img
		687	}
		688
		689	sub cover($;$$) {
		690	my $img = pop;
		691	my $w = ($_[0] \|\| TW) / $img->w;
		692	my $h = ($_[1] \|\| TH) / $img->h;
		693	scale +(max $w, $h), $img
		694	}
		695
		696	=item move $dx, $dy, $img
		697
		698	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
		699	the vertical.
		700
		701	Example: move the image right by 20 pixels and down by 30.
		702
		703	move 20, 30, ...
		704
		705	=item align $xalign, $yalign, $img
		706
		707	Aligns the image according to a factor - C<0> means the image is moved to
		708	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		709	exactly centered and C<1> means it touches the right or bottom edge.
		710
		711	Example: remove any visible border around an image, center it vertically but move
		712	it to the right hand side.
		713
		714	align 1, 0.5, pad $img
		715
		716	=item center $img
		717
		718	=item center $width, $height, $img
		719
		720	Centers the image, i.e. the center of the image is moved to the center of
		721	the terminal window (or the box specified by C<$width> and C<$height> if
		722	given).
		723
		724	Example: load an image and center it.
		725
		726	center keep { pad load "mybg.png" }
		727
		728	=item rootalign $img
		729
		730	Moves the image so that it appears glued to the screen as opposed to the
		731	window. This gives the illusion of a larger area behind the window. It is
		732	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
		733	top left of the screen.
		734
		735	Example: load a background image, put it in mirror mode and root align it.
		736
		737	rootalign keep { mirror load "mybg.png" }
		738
		739	Example: take the screen background and align it, giving the illusion of
		740	transparency as long as the window isn't in front of other windows.
		741
		742	rootalign root
		743
		744	=cut
351		745
352	sub move($$;$) {	746	sub move($$;$) {
353	my $img = pop->clone;	747	my $img = pop->clone;
354	$img->move ($_[0], $_[1]);	748	$img->move ($_[0], $_[1]);
355	$img	749	$img
356	}	750	}
357		751
		752	sub align($;$$) {
		753	my $img = pop;
		754
		755	move $_[0] * (TW - $img->w),
		756	$_[1] * (TH - $img->h),
		757	$img
		758	}
		759
		760	sub center($;$$) {
		761	my $img = pop;
		762	my $w = $_[0] \|\| TW;
		763	my $h = $_[1] \|\| TH;
		764
		765	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		766	}
		767
		768	sub rootalign($) {
		769	move -TX, -TY, $_[0]
		770	}
		771
		772	=item rotate $center_x, $center_y, $degrees, $img
		773
		774	Rotates the image clockwise by C<$degrees> degrees, around the point at
		775	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		776
		777	Example: rotate the image by 90 degrees around it's center.
		778
		779	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		780
		781	=cut
		782
358	sub rotate($$$$$$) {	783	sub rotate($$$$) {
359	my $img = pop;	784	my $img = pop;
360	$img->rotate (	785	$img->rotate (
361	$_[0],	786	$_[0] * ($img->w + $img->x),
362	$_[1],	787	$_[1] * ($img->h + $img->y),
363	$_[2] * $img->w * .01,
364	$_[3] * $img->h * .01,
365	$_[4] * (3.14159265 / 180),	788	$_[2] * (3.14159265 / 180),
366	)	789	)
367	}	790	}
		791
		792	=back
		793
		794	=head2 COLOUR MODIFICATIONS
		795
		796	The following operators change the pixels of the image.
		797
		798	=over 4
		799
		800	=item tint $color, $img
		801
		802	Tints the image in the given colour.
		803
		804	Example: tint the image red.
		805
		806	tint "red", load "rgb.png"
		807
		808	Example: the same, but specify the colour by component.
		809
		810	tint [1, 0, 0], load "rgb.png"
		811
		812	=cut
		813
		814	sub tint($$) {
		815	$_[1]->tint ($_[0])
		816	}
		817
		818	=item contrast $factor, $img
		819
		820	=item contrast $r, $g, $b, $img
		821
		822	=item contrast $r, $g, $b, $a, $img
		823
		824	Adjusts the I<contrast> of an image.
		825
		826	The first form applies a single C<$factor> to red, green and blue, the
		827	second form applies separate factors to each colour channel, and the last
		828	form includes the alpha channel.
		829
		830	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		831	contrast.
		832
		833	Due to limitations in the underlying XRender extension, lowering contrast
		834	also reduces brightness, while increasing contrast currently also
		835	increases brightness.
		836
		837	=item brightness $bias, $img
		838
		839	=item brightness $r, $g, $b, $img
		840
		841	=item brightness $r, $g, $b, $a, $img
		842
		843	Adjusts the brightness of an image.
		844
		845	The first form applies a single C<$bias> to red, green and blue, the
		846	second form applies separate biases to each colour channel, and the last
		847	form includes the alpha channel.
		848
		849	Values less than 0 reduce brightness, while values larger than 0 increase
		850	it. Useful range is from -1 to 1 - the former results in a black, the
		851	latter in a white picture.
		852
		853	Due to idiosyncrasies in the underlying XRender extension, biases less
		854	than zero can be I<very> slow.
		855
		856	You can also try the experimental(!) C<muladd> operator.
		857
		858	=cut
		859
		860	sub contrast($$;$$;$) {
		861	my $img = pop;
		862	my ($r, $g, $b, $a) = @_;
		863
		864	($g, $b) = ($r, $r) if @_ < 3;
		865	$a = 1 if @_ < 4;
		866
		867	$img = $img->clone;
		868	$img->contrast ($r, $g, $b, $a);
		869	$img
		870	}
		871
		872	sub brightness($$;$$;$) {
		873	my $img = pop;
		874	my ($r, $g, $b, $a) = @_;
		875
		876	($g, $b) = ($r, $r) if @_ < 3;
		877	$a = 1 if @_ < 4;
		878
		879	$img = $img->clone;
		880	$img->brightness ($r, $g, $b, $a);
		881	$img
		882	}
		883
		884	=item muladd $mul, $add, $img # EXPERIMENTAL
		885
		886	First multipliesthe pixels by C<$mul>, then adds C<$add>. This cna be used
		887	to implement brightness and contrast at the same time, with a wider value
		888	range than contrast and brightness operators.
		889
		890	Due to numerous bugs in XRender implementations, it can also introduce a
		891	number of visual artifacts.
		892
		893	Example: increase contrast by a factor of C<$c> without changing image
		894	brightness too much.
		895
		896	muladd $c, (1 - $c) * 0.5, $img
		897
		898	=cut
		899
		900	sub muladd($$$) {
		901	$_[2]->muladd ($_[0], $_[1])
		902	}
		903
		904	=item blur $radius, $img
		905
		906	=item blur $radius_horz, $radius_vert, $img
		907
		908	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
		909	can also be specified separately.
		910
		911	Blurring is often I<very> slow, at least compared or other
		912	operators. Larger blur radii are slower than smaller ones, too, so if you
		913	don't want to freeze your screen for long times, start experimenting with
		914	low values for radius (<5).
		915
		916	=cut
368		917
369	sub blur($$;$) {	918	sub blur($$;$) {
370	my $img = pop;	919	my $img = pop;
371	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	920	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
372	}	921	}
373		922
374	sub contrast($$;$$;$) {
375	my $img = pop;
376	my ($r, $g, $b, $a) = @_;
377
378	($g, $b) = ($r, $r) if @_ < 4;
379	$a = 1 if @_ < 5;
380
381	$img = $img->clone;
382	$img->contrast ($r, $g, $b, $a);
383	$img
384	}
385
386	sub brightness($$;$$;$) {
387	my $img = pop;
388	my ($r, $g, $b, $a) = @_;
389
390	($g, $b) = ($r, $r) if @_ < 4;
391	$a = 1 if @_ < 5;
392
393	$img = $img->clone;
394	$img->brightness ($r, $g, $b, $a);
395	$img
396	}
397
398	=back	923	=back
399		924
		925	=head2 OTHER STUFF
		926
		927	Anything that didn't fit any of the other categories, even after applying
		928	force and closing our eyes.
		929
		930	=over 4
		931
		932	=item keep { ... }
		933
		934	This operator takes a code block as argument, that is, one or more
		935	statements enclosed by braces.
		936
		937	The trick is that this code block is only evaluated when the outcome
		938	changes - on other calls the C<keep> simply returns the image it computed
		939	previously (yes, it should only be used with images). Or in other words,
		940	C<keep> I<caches> the result of the code block so it doesn't need to be
		941	computed again.
		942
		943	This can be extremely useful to avoid redoing slow operations - for
		944	example, if your background expression takes the root background, blurs it
		945	and then root-aligns it it would have to blur the root background on every
		946	window move or resize.
		947
		948	Another example is C<load>, which can be quite slow.
		949
		950	In fact, urxvt itself encloses the whole expression in some kind of
		951	C<keep> block so it only is reevaluated as required.
		952
		953	Putting the blur into a C<keep> block will make sure the blur is only done
		954	once, while the C<rootalign> is still done each time the window moves.
		955
		956	rootalign keep { blur 10, root }
		957
		958	This leaves the question of how to force reevaluation of the block,
		959	in case the root background changes: If expression inside the block
		960	is sensitive to some event (root background changes, window geometry
		961	changes), then it will be reevaluated automatically as needed.
		962
		963	=cut
		964
		965	sub keep(&) {
		966	my $id = $_[0]+0;
		967
		968	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		969
		970	unless ($frame->[FR_CACHE]) {
		971	$frame->[FR_CACHE] = [ $_[0]() ];
		972
		973	my $self = $self;
		974	my $frame = $frame;
		975	Scalar::Util::weaken $frame;
		976	$self->compile_frame ($frame, sub {
		977	# clear this frame cache, also for all parents
		978	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		979	undef $frame->[FR_CACHE];
		980	}
		981
		982	$self->recalculate;
		983	});
		984	};
		985
		986	# in scalar context we always return the first original result, which
		987	# is not quite how perl works.
		988	wantarray
		989	? @{ $frame->[FR_CACHE] }
		990	: $frame->[FR_CACHE][0]
		991	}
		992
		993	# sub keep_clear() {
		994	# delete $self->{frame_cache};
		995	# }
		996
		997	=back
		998
400	=cut	999	=cut
401		1000
402	}	1001	}
403		1002
404	sub parse_expr {	1003	sub parse_expr {
405	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	1004	my $expr = eval
		1005	"sub {\n"
		1006	. "package urxvt::bgdsl;\n"
		1007	. "#line 0 'background expression'\n"
		1008	. "$_[0]\n"
		1009	. "}";
406	die if $@;	1010	die if $@;
407	$expr	1011	$expr
408	}	1012	}
409		1013
410	# compiles a parsed expression	1014	# compiles a parsed expression
411	sub set_expr {	1015	sub set_expr {
412	my ($self, $expr) = @_;	1016	my ($self, $expr) = @_;
413		1017
		1018	$self->{root} = []; # the outermost frame
414	$self->{expr} = $expr;	1019	$self->{expr} = $expr;
415	$self->recalculate;	1020	$self->recalculate;
		1021	}
		1022
		1023	# takes a hash of sensitivity indicators and installs watchers
		1024	sub compile_frame {
		1025	my ($self, $frame, $cb) = @_;
		1026
		1027	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		1028	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		1029
		1030	# don't keep stuff alive
		1031	Scalar::Util::weaken $state;
		1032
		1033	if ($again->{nested}) {
		1034	$state->{nested} = 1;
		1035	} else {
		1036	delete $state->{nested};
		1037	}
		1038
		1039	if (my $interval = $again->{time}) {
		1040	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		1041	if $state->{time}[0] != $interval;
		1042
		1043	# callback might have changed, although we could just rule that out
		1044	$state->{time}[1]->cb (sub {
		1045	++$state->{counter};
		1046	$cb->();
		1047	});
		1048	} else {
		1049	delete $state->{time};
		1050	}
		1051
		1052	if ($again->{position}) {
		1053	$state->{position} = $self->on (position_change => $cb);
		1054	} else {
		1055	delete $state->{position};
		1056	}
		1057
		1058	if ($again->{size}) {
		1059	$state->{size} = $self->on (size_change => $cb);
		1060	} else {
		1061	delete $state->{size};
		1062	}
		1063
		1064	if ($again->{rootpmap}) {
		1065	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		1066	} else {
		1067	delete $state->{rootpmap};
		1068	}
416	}	1069	}
417		1070
418	# evaluate the current bg expression	1071	# evaluate the current bg expression
419	sub recalculate {	1072	sub recalculate {
420	my ($arg_self) = @_;	1073	my ($arg_self) = @_;
…		…
430		1083
431	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1084	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
432		1085
433	# set environment to evaluate user expression	1086	# set environment to evaluate user expression
434		1087
435	local $self = $arg_self;	1088	local $self = $arg_self;
436		1089	local $HOME = $ENV{HOME};
437	local $old = $self->{state};	1090	local $frame = $self->{root};
438	local $new = my $state = $self->{state} = {};
439		1091
440	($x, $y, $w, $h) =
441	$self->background_geometry ($self->{border});	1092	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
442		1093
443	# evaluate user expression	1094	# evaluate user expression
444		1095
445	my $img = eval { $self->{expr}->() };	1096	my @img = eval { $self->{expr}->() };
446	warn $@ if $@;#d#	1097	die $@ if $@;
		1098	die "background-expr did not return anything.\n" unless @img;
		1099	die "background-expr: expected image(s), got something else.\n"
447	die if !UNIVERSAL::isa $img, "urxvt::img";	1100	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
448		1101
449	$state->{size_sensitive} = 1	1102	my $img = urxvt::bgdsl::merge @img;
		1103
		1104	$frame->[FR_AGAIN]{size} = 1
450	if $img->repeat_mode != urxvt::RepeatNormal;	1105	if $img->repeat_mode != urxvt::RepeatNormal;
451		1106
452	# if the expression is sensitive to external events, prepare reevaluation then	1107	# if the expression is sensitive to external events, prepare reevaluation then
453		1108	$self->compile_frame ($frame, sub { $arg_self->recalculate });
454	my $repeat;
455
456	if (my $again = $state->{again}) {
457	$repeat = 1;
458	my $self = $self;
459	$state->{timer} = $again == $old->{again}
460	? $old->{timer}
461	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
462	++$self->{counter};
463	$self->recalculate
464	});
465	}
466
467	if (delete $state->{position_sensitive}) {
468	$repeat = 1;
469	$self->enable (position_change => sub { $_[0]->recalculate });
470	} else {
471	$self->disable ("position_change");
472	}
473
474	if (delete $state->{size_sensitive}) {
475	$repeat = 1;
476	$self->enable (size_change => sub { $_[0]->recalculate });
477	} else {
478	$self->disable ("size_change");
479	}
480
481	if (delete $state->{rootpmap_sensitive}) {
482	$repeat = 1;
483	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
484	} else {
485	$self->disable ("rootpmap_change");
486	}
487		1109
488	# clear stuff we no longer need	1110	# clear stuff we no longer need
489		1111
490	%$old = ();	1112	# unless (%{ $frame->[FR_STATE] }) {
491
492	unless ($repeat) {
493	delete $self->{state};	1113	# delete $self->{state};
494	delete $self->{expr};	1114	# delete $self->{expr};
495	}	1115	# }
496		1116
497	# set background pixmap	1117	# set background pixmap
498		1118
499	$self->set_background ($img, $self->{border});	1119	$self->set_background ($img, $self->{border});
500	$self->scr_recolour (0);	1120	$self->scr_recolour (0);
…		…
502	}	1122	}
503		1123
504	sub on_start {	1124	sub on_start {
505	my ($self) = @_;	1125	my ($self) = @_;
506		1126
507	my $expr = $self->x_resource ("background.expr")	1127	my $expr = $self->x_resource ("%.expr")
508	or return;	1128	or return;
509		1129
		1130	$self->has_render
		1131	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1132
510	$self->set_expr (parse_expr $expr);	1133	$self->set_expr (parse_expr $expr);
511	$self->{border} = $self->x_resource_boolean ("background.border");	1134	$self->{border} = $self->x_resource_boolean ("%.border");
		1135
		1136	$MIN_INTERVAL = $self->x_resource ("%.interval");
512		1137
513	()	1138	()
514	}	1139	}
515		1140

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.35 by root, Fri Jun 8 08:06:38 2012 UTC vs. Revision 1.75 by root, Fri Aug 10 20:07:11 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.35 by root, Fri Jun 8 08:06:38 2012 UTC vs.
Revision 1.75 by root, Fri Aug 10 20:07:11 2012 UTC