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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.39 by root, Fri Jun 8 22:19:03 2012 UTC vs.
Revision 1.71 by root, Mon Jul 2 01:40:41 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	urxvt --background-expr 'background expression'	13	urxvt --background-expr 'background expression'
13	--background-border	14	--background-border
		15	--background-interval seconds
14		16
15	=head2 DESCRIPTION	17	=head1 DESCRIPTION
16		18
17	This extension manages the terminal background by creating a picture that	19	This extension manages the terminal background by creating a picture that
18	is behind the text, replacing the normal background colour.	20	is behind the text, replacing the normal background colour.
19		21
20	It does so by evaluating a Perl expression that I<calculates> the image on	22	It does so by evaluating a Perl expression that I<calculates> the image on
24	to be as simple as possible.	26	to be as simple as possible.
25		27
26	For example, to load an image and scale it to the window size, you would	28	For example, to load an image and scale it to the window size, you would
27	use:	29	use:
28		30
29	urxvt --background-expr 'scale load "/path/to/mybg.png"'	31	urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
30		32
31	Or specified as a X resource:	33	Or specified as a X resource:
32		34
33	URxvt.background-expr: scale load "/path/to/mybg.png"	35	URxvt.background-expr: scale keep { load "/path/to/mybg.png" }
34		36
35	=head2 THEORY OF OPERATION	37	=head1 THEORY OF OPERATION
36		38
37	At startup, just before the window is mapped for the first time, the	39	At startup, just before the window is mapped for the first time, the
38	expression is evaluated and must yield an image. The image is then	40	expression is evaluated and must yield an image. The image is then
39	extended as necessary to cover the whole terminal window, and is set as a	41	extended as necessary to cover the whole terminal window, and is set as a
40	background pixmap.	42	background pixmap.
…		…
51	If any of the parameters that the expression relies on changes (when the	53	If any of the parameters that the expression relies on changes (when the
52	window is moved or resized, its position or size changes; when the root	54	window is moved or resized, its position or size changes; when the root
53	pixmap is replaced by another one the root background changes; or when the	55	pixmap is replaced by another one the root background changes; or when the
54	timer elapses), then the expression will be evaluated again.	56	timer elapses), then the expression will be evaluated again.
55		57
56	For example, an expression such as C<scale load "$HOME/mybg.png"> scales the	58	For example, an expression such as C<scale keep { load "$HOME/mybg.png"
57	image to the window size, so it relies on the window size and will	59	}> scales the image to the window size, so it relies on the window size
58	be reevaluated each time it is changed, but not when it moves for	60	and will be reevaluated each time it is changed, but not when it moves for
59	example. That ensures that the picture always fills the terminal, even	61	example. That ensures that the picture always fills the terminal, even
60	after it's size changes.	62	after its size changes.
61		63
62	=head3 EXPRESSIONS	64	=head2 EXPRESSIONS
63		65
64	Expressions are normal Perl expressions, in fact, they are Perl blocks -	66	Expressions are normal Perl expressions, in fact, they are Perl blocks -
65	which means you could use multiple lines and statements:	67	which means you could use multiple lines and statements:
66		68
		69	scale keep {
67	again 3600;	70	again 3600;
68	if (localtime now)[6]) {	71	if (localtime now)[6]) {
69	return scale load "$HOME/weekday.png";	72	return load "$HOME/weekday.png";
70	} else {	73	} else {
71	return scale load "$HOME/sunday.png";	74	return load "$HOME/sunday.png";
		75	}
72	}	76	}
73		77
74	This expression gets evaluated once per hour. It will set F<sunday.png> as	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
75	background on Sundays, and F<weekday.png> on all other days.	80	Sundays, and F<weekday.png> on all other days.
76		81
77	Fortunately, we expect that most expressions will be much simpler, with	82	Fortunately, we expect that most expressions will be much simpler, with
78	little Perl knowledge needed.	83	little Perl knowledge needed.
79		84
80	Basically, you always start with a function that "generates" an image	85	Basically, you always start with a function that "generates" an image
…		…
97	its result becomes the argument to the C<scale> function.	102	its result becomes the argument to the C<scale> function.
98		103
99	Many operators also allow some parameters preceding the input image	104	Many operators also allow some parameters preceding the input image
100	that modify its behaviour. For example, C<scale> without any additional	105	that modify its behaviour. For example, C<scale> without any additional
101	arguments scales the image to size of the terminal window. If you specify	106	arguments scales the image to size of the terminal window. If you specify
102	an additional argument, it uses it as a percentage:	107	an additional argument, it uses it as a scale factor (multiply by 100 to
		108	get a percentage):
103		109
104	scale 200, load "$HOME/mypic.png"	110	scale 2, load "$HOME/mypic.png"
105		111
106	This enlarges the image by a factor of 2 (200%). As you can see, C<scale>	112	This enlarges the image by a factor of 2 (200%). As you can see, C<scale>
107	has now two arguments, the C<200> and the C<load> expression, while	113	has now two arguments, the C<200> and the C<load> expression, while
108	C<load> only has one argument. Arguments are separated from each other by	114	C<load> only has one argument. Arguments are separated from each other by
109	commas.	115	commas.
110		116
111	Scale also accepts two arguments, which are then separate factors for both	117	Scale also accepts two arguments, which are then separate factors for both
112	horizontal and vertical dimensions. For example, this halves the image	118	horizontal and vertical dimensions. For example, this halves the image
113	width and doubles the image height:	119	width and doubles the image height:
114		120
115	scale 50, 200, load "$HOME/mypic.png"	121	scale 0.5, 2, load "$HOME/mypic.png"
116		122
117	Other effects than scalign are also readily available, for exmaple, you can	123	IF you try out these expressions, you might suffer from some sluggishness,
118	tile the image to fill the whole window, instead of resizing it:	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:
119		127
		128	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		129
		130	The C<keep> operator executes all the statements inside the braces only
		131	once, or when it thinks the outcome might change. In other cases it
		132	returns the last value computed by the brace block.
		133
		134	This means that the C<load> is only executed once, which makes it much
		135	faster, but also means that more memory is being used, because the loaded
		136	image must be kept in memory at all times. In this expression, the
		137	trade-off is likely worth it.
		138
		139	But back to effects: Other effects than scaling are also readily
		140	available, for example, you can tile the image to fill the whole window,
		141	instead of resizing it:
		142
120	tile load "$HOME/mypic.png"	143	tile keep { load "$HOME/mypic.png" }
121		144
122	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator	145	In fact, images returned by C<load> are in C<tile> mode by default, so the
123	is kind of superfluous.	146	C<tile> operator is kind of superfluous.
124		147
125	Another common effect is to mirror the image, so that the same edges touch:	148	Another common effect is to mirror the image, so that the same edges
		149	touch:
126		150
127	mirror load "$HOME/mypic.png"	151	mirror keep { load "$HOME/mypic.png" }
128		152
129	This is also a typical background expression:	153	Another common background expression is:
130		154
131	rootalign root	155	rootalign root
132		156
133	It first takes a snapshot of the screen background image, and then	157	This one first takes a snapshot of the screen background image, and then
134	moves it to the upper left corner of the screen - the result is	158	moves it to the upper left corner of the screen (as opposed to the upper
135	pseudo-transparency, as the image seems to be static while the window is	159	left corner of the terminal window)- the result is pseudo-transparency:
136	moved around.	160	the image seems to be static while the window is moved around.
137		161
138	=head3 CYCLES AND CACHING	162	=head2 COLOUR SPECIFICATIONS
139		163
140	As has been mentioned before, the expression might be evaluated multiple	164	Whenever an oprator expects a "colour", then this can be specified in one
141	times. Each time the expression is reevaluated, a new cycle is said to	165	of two ways: Either as string with an X11 colour specification, such as:
142	have begun. Many operators cache their results till the next cycle.
143		166
144	For example, the C<load> operator keeps a copy of the image. If it is	167	"red" # named colour
145	asked to load the same image on the next cycle it will not load it again,	168	"#f00" # simple rgb
146	but return the cached copy.	169	"[50]red" # red with 50% alpha
		170	"TekHVC:300/50/50" # anything goes
147		171
148	This only works for one cycle though, so as long as you load the same	172	OR as an array reference with one, three or four components:
149	image every time, it will always be cached, but when you load a different
150	image, it will forget about the first one.
151		173
152	This allows you to either speed things up by keeping multiple images in	174	[0.5] # 50% gray, 100% alpha
153	memory, or comserve memory by loading images more often.	175	[0.5, 0, 0] # dark red, no green or blur, 100% alpha
		176	[0.5, 0, 0, 0.7] # same with explicit 70% alpha
154		177
155	For example, you can keep two images in memory and use a random one like	178	=head2 CACHING AND SENSITIVITY
156	this:
157		179
158	my $img1 = load "img1.png";	180	Since some operations (such as C<load> and C<blur>) can take a long time,
159	my $img2 = load "img2.png";	181	caching results can be very important for a smooth operation. Caching can
160	(0.5 > rand) ? $img1 : $img2	182	also be useful to reduce memory usage, though, for example, when an image
		183	is cached by C<load>, it could be shared by multiple terminal windows
		184	running inside urxvtd.
161		185
162	Since both images are "loaded" every time the expression is evaluated,	186	=head3 C<keep { ... }> caching
163	they are always kept in memory. Contrast this version:
164		187
165	my $path1 = "img1.png";	188	The most important way to cache expensive operations is to use C<keep {
166	my $path2 = "img2.png";	189	... }>. The C<keep> operator takes a block of multiple statements enclosed
167	load ((0.5 > rand) ? $path1 : $path2)	190	by C<{}> and keeps the return value in memory.
168		191
169	Here, a path is selected randomly, and load is only called for one image,	192	An expression can be "sensitive" to various external events, such as
170	so keeps only one image in memory. If, on the next evaluation, luck	193	scaling or moving the window, root background changes and timers. Simply
171	decides to use the other path, then it will have to load that image again.	194	using an expression (such as C<scale> without parameters) that depends on
		195	certain changing values (called "variables"), or using those variables
		196	directly, will make an expression sensitive to these events - for example,
		197	using C<scale> or C<TW> will make the expression sensitive to the terminal
		198	size, and thus to resizing events.
172		199
		200	When such an event happens, C<keep> will automatically trigger a
		201	reevaluation of the whole expression with the new value of the expression.
		202
		203	C<keep> is most useful for expensive operations, such as C<blur>:
		204
		205	rootalign keep { blur 20, root }
		206
		207	This makes a blurred copy of the root background once, and on subsequent
		208	calls, just root-aligns it. Since C<blur> is usually quite slow and
		209	C<rootalign> is quite fast, this trades extra memory (for the cached
		210	blurred pixmap) with speed (blur only needs to be redone when root
		211	changes).
		212
		213	=head3 C<load> caching
		214
		215	The C<load> operator itself does not keep images in memory, but as long as
		216	the image is still in memory, C<load> will use the in-memory image instead
		217	of loading it freshly from disk.
		218
		219	That means that this expression:
		220
		221	keep { load "$HOME/path..." }
		222
		223	Not only caches the image in memory, other terminal instances that try to
		224	C<load> it can reuse that in-memory copy.
		225
173	=head2 REFERENCE	226	=head1 REFERENCE
174		227
175	=head3 COMMAND LINE SWITCHES	228	=head2 COMMAND LINE SWITCHES
176		229
177	=over 4	230	=over 4
178		231
179	=item --background-expr perl-expression	232	=item --background-expr perl-expression
180		233
…		…
186	overwriting borders and any other areas, such as the scrollbar.	239	overwriting borders and any other areas, such as the scrollbar.
187		240
188	Specifying this flag changes the behaviour, so that the image only	241	Specifying this flag changes the behaviour, so that the image only
189	replaces the background of the character area.	242	replaces the background of the character area.
190		243
		244	=item --background-interval seconds
		245
		246	Since some operations in the underlying XRender extension can effectively
		247	freeze your X-server for prolonged time, this extension enforces a minimum
		248	time between updates, which is normally about 0.1 seconds.
		249
		250	If you want to do updates more often, you can decrease this safety
		251	interval with this switch.
		252
191	=back	253	=back
192		254
193	=cut	255	=cut
194		256
		257	our %_IMG_CACHE;
195	our $HOME;	258	our $HOME;
196	our ($self, $old, $new);	259	our ($self, $frame);
197	our ($x, $y, $w, $h);	260	our ($x, $y, $w, $h);
198		261
199	# enforce at least this interval between updates	262	# enforce at least this interval between updates
200	our $MIN_INTERVAL = 1/100;	263	our $MIN_INTERVAL = 6/59.951;
201		264
202	{	265	{
203	package urxvt::bgdsl; # background language	266	package urxvt::bgdsl; # background language
		267
		268	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
		269	sub FR_CACHE () { 1 } # cached values
		270	sub FR_AGAIN () { 2 } # what this expr is sensitive to
		271	sub FR_STATE () { 3 } # watchers etc.
		272
		273	use List::Util qw(min max sum shuffle);
204		274
205	=head2 PROVIDERS/GENERATORS	275	=head2 PROVIDERS/GENERATORS
206		276
207	These functions provide an image, by loading it from disk, grabbing it	277	These functions provide an image, by loading it from disk, grabbing it
208	from the root screen or by simply generating it. They are used as starting	278	from the root screen or by simply generating it. They are used as starting
…		…
213	=item load $path	283	=item load $path
214		284
215	Loads the image at the given C<$path>. The image is set to plane tiling	285	Loads the image at the given C<$path>. The image is set to plane tiling
216	mode.	286	mode.
217		287
218	Loaded images will be cached for one cycle.	288	If the image is already in memory (e.g. because another terminal instance
		289	uses it), then the in-memory copy us returned instead.
		290
		291	=item load_uc $path
		292
		293	Load uncached - same as load, but does not cache the image, which means it
		294	is I<always> loaded from the filesystem again.
219		295
220	=cut	296	=cut
221		297
222	sub load($) {	298	sub load($) {
223	my ($path) = @_;	299	my ($path) = @_;
224		300
225	$new->{load}{$path} = $old->{load}{$path} \|\| $self->new_img_from_file ($path);	301	$_IMG_CACHE{$path} \|\| do {
		302	my $img = $self->new_img_from_file ($path);
		303	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		304	$img
		305	}
226	}	306	}
227		307
228	=item root	308	=item root
229		309
230	Returns the root window pixmap, that is, hopefully, the background image	310	Returns the root window pixmap, that is, hopefully, the background image
231	of your screen. The image is set to extend mode.	311	of your screen.
232		312
233	This function makes your expression root sensitive, that means it will be	313	This function makes your expression root sensitive, that means it will be
234	reevaluated when the bg image changes.	314	reevaluated when the bg image changes.
235		315
236	=cut	316	=cut
237		317
238	sub root() {	318	sub root() {
239	$new->{rootpmap_sensitive} = 1;	319	$frame->[FR_AGAIN]{rootpmap} = 1;
240	die "root op not supported, exg, we need you";	320	$self->new_img_from_root
241	}	321	}
242		322
243	=item solid $colour	323	=item solid $colour
244		324
245	=item solid $width, $height, $colour	325	=item solid $width, $height, $colour
246		326
247	Creates a new image and completely fills it with the given colour. The	327	Creates a new image and completely fills it with the given colour. The
248	image is set to tiling mode.	328	image is set to tiling mode.
249		329
250	If <$width> and C<$height> are omitted, it creates a 1x1 image, which is	330	If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
251	useful for solid backgrounds or for use in filtering effects.	331	useful for solid backgrounds or for use in filtering effects.
252		332
253	=cut	333	=cut
254		334
255	sub solid($$;$) {	335	sub solid($;$$) {
256	my $colour = pop;	336	my $colour = pop;
257		337
258	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	338	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
259	$img->fill ($colour);	339	$img->fill ($colour);
260	$img	340	$img
261	}	341	}
262		342
263	=back	343	=item clone $img
264		344
265	=head2 VARIABLES	345	Returns an exact copy of the image. This is useful if you want to have
		346	multiple copies of the same image to apply different effects to.
266		347
267	The following functions provide variable data such as the terminal
268	window dimensions. Most of them make your expression sensitive to some
269	events, for example using C<TW> (terminal width) means your expression is
270	evaluated again when the terminal is resized.
271
272	=over 4
273
274	=item TX
275
276	=item TY
277
278	Return the X and Y coordinates of the terminal window (the terminal
279	window is the full window by default, and the character area only when in
280	border-respect mode).
281
282	Using these functions make your expression sensitive to window moves.
283
284	These functions are mainly useful to align images to the root window.
285
286	Example: load an image and align it so it looks as if anchored to the
287	background.
288
289	move -TX, -TY, load "mybg.png"
290
291	=item TW
292
293	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
294	terminal window is the full window by default, and the character area only
295	when in border-respect mode).
296
297	Using these functions make your expression sensitive to window resizes.
298
299	These functions are mainly useful to scale images, or to clip images to
300	the window size to conserve memory.
301
302	Example: take the screen background, clip it to the window size, blur it a
303	bit, align it to the window position and use it as background.
304
305	clip move -TX, -TY, blur 5, root
306
307	=cut	348	=cut
308		349
309	sub TX() { $new->{position_sensitive} = 1; $x }
310	sub TY() { $new->{position_sensitive} = 1; $y }
311	sub TW() { $new->{size_sensitive} = 1; $w }
312	sub TH() { $new->{size_sensitive} = 1; $h }
313
314	=item now
315
316	Returns the current time as (fractional) seconds since the epoch.
317
318	Using this expression does I<not> make your expression sensitive to time,
319	but the next two functions do.
320
321	=item again $seconds
322
323	When this function is used the expression will be reevaluated again in
324	C<$seconds> seconds.
325
326	Example: load some image and rotate it according to the time of day (as if it were
327	the hour pointer of a clock). Update this image every minute.
328
329	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
330
331	=item counter $seconds
332
333	Like C<again>, but also returns an increasing counter value, starting at
334	0, which might be useful for some simple animation effects.
335
336	=cut
337
338	sub now() { urxvt::NOW }
339
340	sub again($) {
341	$new->{again} = $_[0];
342	}
343
344	sub counter($) {	350	sub clone($) {
345	$new->{again} = $_[0];	351	$_[0]->clone
346	$self->{counter} + 0
347	}	352	}
348		353
349	=back	354	=item merge $img ...
		355
		356	Takes any number of images and merges them together, creating a single
		357	image containing them all. The tiling mode of the first image is used as
		358	the tiling mode of the resulting image.
		359
		360	This function is called automatically when an expression returns multiple
		361	images.
		362
		363	=cut
		364
		365	sub merge(@) {
		366	return $_[0] unless $#_;
		367
		368	# rather annoyingly clumsy, but optimisation is for another time
		369
		370	my $x0 = +1e9;
		371	my $y0 = +1e9;
		372	my $x1 = -1e9;
		373	my $y1 = -1e9;
		374
		375	for (@_) {
		376	my ($x, $y, $w, $h) = $_->geometry;
		377
		378	$x0 = $x if $x0 > $x;
		379	$y0 = $y if $y0 > $y;
		380
		381	$x += $w;
		382	$y += $h;
		383
		384	$x1 = $x if $x1 < $x;
		385	$y1 = $y if $y1 < $y;
		386	}
		387
		388	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		389	$base->repeat_mode ($_[0]->repeat_mode);
		390	$base->fill ([0, 0, 0, 0]);
		391
		392	$base->draw ($_)
		393	for @_;
		394
		395	$base
		396	}
350		397
351	=head2 TILING MODES	398	=head2 TILING MODES
352		399
353	The following operators modify the tiling mode of an image, that is, the	400	The following operators modify the tiling mode of an image, that is, the
354	way that pixels outside the image area are painted when the image is used.	401	way that pixels outside the image area are painted when the image is used.
…		…
384	become transparent. This mode is most useful when you want to place an	431	become transparent. This mode is most useful when you want to place an
385	image over another image or the background colour while leaving all	432	image over another image or the background colour while leaving all
386	background pixels outside the image unchanged.	433	background pixels outside the image unchanged.
387		434
388	Example: load an image and display it in the upper left corner. The rest	435	Example: load an image and display it in the upper left corner. The rest
389	of the space is left "empty" (transparent or wahtever your compisotr does	436	of the space is left "empty" (transparent or whatever your compositor does
390	in alpha mode, else background colour).	437	in alpha mode, else background colour).
391		438
392	pad load "mybg.png"	439	pad load "mybg.png"
393		440
394	=item extend $img	441	=item extend $img
395		442
396	Extends the image over the whole plane, using the closest pixel in the	443	Extends the image over the whole plane, using the closest pixel in the
397	area outside the image. This mode is mostly useful when you more complex	444	area outside the image. This mode is mostly useful when you use more complex
398	filtering operations and want the pixels outside the image to have the	445	filtering operations and want the pixels outside the image to have the
399	same values as the pixels near the edge.	446	same values as the pixels near the edge.
400		447
401	Example: just for curiosity, how does this pixel extension stuff work?	448	Example: just for curiosity, how does this pixel extension stuff work?
402		449
…		…
428	$img	475	$img
429	}	476	}
430		477
431	=back	478	=back
432		479
433	=head2 PIXEL OPERATORS	480	=head2 VARIABLE VALUES
434		481
435	The following operators modify the image pixels in various ways.	482	The following functions provide variable data such as the terminal window
		483	dimensions. They are not (Perl-) variables, they just return stuff that
		484	varies. Most of them make your expression sensitive to some events, for
		485	example using C<TW> (terminal width) means your expression is evaluated
		486	again when the terminal is resized.
436		487
437	=over 4	488	=over 4
438		489
439	=item clone $img	490	=item TX
440		491
441	Returns an exact copy of the image.	492	=item TY
442		493
443	=cut	494	Return the X and Y coordinates of the terminal window (the terminal
		495	window is the full window by default, and the character area only when in
		496	border-respect mode).
444		497
		498	Using these functions make your expression sensitive to window moves.
		499
		500	These functions are mainly useful to align images to the root window.
		501
		502	Example: load an image and align it so it looks as if anchored to the
		503	background (that's exactly what C<rootalign> does btw.):
		504
		505	move -TX, -TY, keep { load "mybg.png" }
		506
		507	=item TW
		508
		509	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		510	terminal window is the full window by default, and the character area only
		511	when in border-respect mode).
		512
		513	Using these functions make your expression sensitive to window resizes.
		514
		515	These functions are mainly useful to scale images, or to clip images to
		516	the window size to conserve memory.
		517
		518	Example: take the screen background, clip it to the window size, blur it a
		519	bit, align it to the window position and use it as background.
		520
		521	clip move -TX, -TY, keep { blur 5, root }
		522
		523	=cut
		524
		525	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
		526	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
		527	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
		528	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
		529
		530	=item now
		531
		532	Returns the current time as (fractional) seconds since the epoch.
		533
		534	Using this expression does I<not> make your expression sensitive to time,
		535	but the next two functions do.
		536
		537	=item again $seconds
		538
		539	When this function is used the expression will be reevaluated again in
		540	C<$seconds> seconds.
		541
		542	Example: load some image and rotate it according to the time of day (as if it were
		543	the hour pointer of a clock). Update this image every minute.
		544
		545	again 60;
		546	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
		547
		548	=item counter $seconds
		549
		550	Like C<again>, but also returns an increasing counter value, starting at
		551	0, which might be useful for some simple animation effects.
		552
		553	=cut
		554
		555	sub now() { urxvt::NOW }
		556
		557	sub again($) {
		558	$frame->[FR_AGAIN]{time} = $_[0];
		559	}
		560
445	sub clone($) {	561	sub counter($) {
446	$_[0]->clone	562	$frame->[FR_AGAIN]{time} = $_[0];
		563	$frame->[FR_STATE]{counter} + 0
447	}	564	}
		565
		566	=back
		567
		568	=head2 SHAPE CHANGING OPERATORS
		569
		570	The following operators modify the shape, size or position of the image.
		571
		572	=over 4
448		573
449	=item clip $img	574	=item clip $img
450		575
451	=item clip $width, $height, $img	576	=item clip $width, $height, $img
452		577
…		…
463	assumed.	588	assumed.
464		589
465	Example: load an image, blur it, and clip it to the window size to save	590	Example: load an image, blur it, and clip it to the window size to save
466	memory.	591	memory.
467		592
468	clip blur 10, load "mybg.png"	593	clip keep { blur 10, load "mybg.png" }
469		594
470	=cut	595	=cut
471		596
472	sub clip($;$$;$$) {	597	sub clip($;$$;$$) {
473	my $img = pop;	598	my $img = pop;
…		…
476	$img->sub_rect ($_[0], $_[1], $w, $h)	601	$img->sub_rect ($_[0], $_[1], $w, $h)
477	}	602	}
478		603
479	=item scale $img	604	=item scale $img
480		605
481	=item scale $size_percent, $img	606	=item scale $size_factor, $img
482		607
483	=item scale $width_percent, $height_percent, $img	608	=item scale $width_factor, $height_factor, $img
484		609
485	Scales the image by the given percentages in horizontal	610	Scales the image by the given factors in horizontal
486	(C<$width_percent>) and vertical (C<$height_percent>) direction.	611	(C<$width>) and vertical (C<$height>) direction.
487		612
488	If only one percentage is give, it is used for both directions.	613	If only one factor is give, it is used for both directions.
489		614
490	If no percentages are given, scales the image to the window size without	615	If no factors are given, scales the image to the window size without
491	keeping aspect.	616	keeping aspect.
492		617
493	=item resize $width, $height, $img	618	=item resize $width, $height, $img
494		619
495	Resizes the image to exactly C<$width> times C<$height> pixels.	620	Resizes the image to exactly C<$width> times C<$height> pixels.
496		621
497	=cut	622	=item fit $img
498		623
499	#TODO: maximise, maximise_fill?	624	=item fit $width, $height, $img
		625
		626	Fits the image into the given C<$width> and C<$height> without changing
		627	aspect, or the terminal size. That means it will be shrunk or grown until
		628	the whole image fits into the given area, possibly leaving borders.
		629
		630	=item cover $img
		631
		632	=item cover $width, $height, $img
		633
		634	Similar to C<fit>, but shrinks or grows until all of the area is covered
		635	by the image, so instead of potentially leaving borders, it will cut off
		636	image data that doesn't fit.
		637
		638	=cut
500		639
501	sub scale($;$;$) {	640	sub scale($;$;$) {
502	my $img = pop;	641	my $img = pop;
503		642
504	@_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01)	643	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
505	: @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01)	644	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
506	: $img->scale (TW, TH)	645	: $img->scale (TW, TH)
507	}	646	}
508		647
509	sub resize($$$) {	648	sub resize($$$) {
510	my $img = pop;	649	my $img = pop;
511	$img->scale ($_[0], $_[1])	650	$img->scale ($_[0], $_[1])
512	}	651	}
513		652
		653	sub fit($;$$) {
		654	my $img = pop;
		655	my $w = ($_[0] \|\| TW) / $img->w;
		656	my $h = ($_[1] \|\| TH) / $img->h;
		657	scale +(min $w, $h), $img
		658	}
		659
		660	sub cover($;$$) {
		661	my $img = pop;
		662	my $w = ($_[0] \|\| TW) / $img->w;
		663	my $h = ($_[1] \|\| TH) / $img->h;
		664	scale +(max $w, $h), $img
		665	}
		666
514	=item move $dx, $dy, $img	667	=item move $dx, $dy, $img
515		668
516	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in	669	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
517	the vertical.	670	the vertical.
518		671
519	Example: move the image right by 20 pixels and down by 30.	672	Example: move the image right by 20 pixels and down by 30.
520		673
521	move 20, 30, ...	674	move 20, 30, ...
		675
		676	=item align $xalign, $yalign, $img
		677
		678	Aligns the image according to a factor - C<0> means the image is moved to
		679	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		680	exactly centered and C<1> means it touches the right or bottom edge.
		681
		682	Example: remove any visible border around an image, center it vertically but move
		683	it to the right hand side.
		684
		685	align 1, 0.5, pad $img
		686
		687	=item center $img
		688
		689	=item center $width, $height, $img
		690
		691	Centers the image, i.e. the center of the image is moved to the center of
		692	the terminal window (or the box specified by C<$width> and C<$height> if
		693	given).
		694
		695	Example: load an image and center it.
		696
		697	center keep { pad load "mybg.png" }
522		698
523	=item rootalign $img	699	=item rootalign $img
524		700
525	Moves the image so that it appears glued to the screen as opposed to the	701	Moves the image so that it appears glued to the screen as opposed to the
526	window. This gives the illusion of a larger area behind the window. It is	702	window. This gives the illusion of a larger area behind the window. It is
527	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	703	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
528	top left of the screen.	704	top left of the screen.
529		705
530	Example: load a background image, put it in mirror mode and root align it.	706	Example: load a background image, put it in mirror mode and root align it.
531		707
532	rootalign mirror load "mybg.png"	708	rootalign keep { mirror load "mybg.png" }
533		709
534	Example: take the screen background and align it, giving the illusion of	710	Example: take the screen background and align it, giving the illusion of
535	transparency as long as the window isn't in front of other windows.	711	transparency as long as the window isn't in front of other windows.
536		712
537	rootalign root	713	rootalign root
538		714
539	=cut	715	=cut
540		716
541	sub move($$;$) {	717	sub move($$;$) {
542	my $img = pop->clone;	718	my $img = pop->clone;
543	$img->move ($_[0], $_[1]);	719	$img->move ($_[0], $_[1]);
544	$img	720	$img
545	}	721	}
546		722
		723	sub align($;$$) {
		724	my $img = pop;
		725
		726	move $_[0] * (TW - $img->w),
		727	$_[1] * (TH - $img->h),
		728	$img
		729	}
		730
		731	sub center($;$$) {
		732	my $img = pop;
		733	my $w = $_[0] \|\| TW;
		734	my $h = $_[1] \|\| TH;
		735
		736	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		737	}
		738
547	sub rootalign($) {	739	sub rootalign($) {
548	move -TX, -TY, $_[0]	740	move -TX, -TY, $_[0]
549	}	741	}
550		742
		743	=item rotate $center_x, $center_y, $degrees, $img
		744
		745	Rotates the image clockwise by C<$degrees> degrees, around the point at
		746	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		747
		748	Example: rotate the image by 90 degrees around it's center.
		749
		750	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		751
		752	=cut
		753
		754	sub rotate($$$$) {
		755	my $img = pop;
		756	$img->rotate (
		757	$_[0] * ($img->w + $img->x),
		758	$_[1] * ($img->h + $img->y),
		759	$_[2] * (3.14159265 / 180),
		760	)
		761	}
		762
		763	=back
		764
		765	=head2 COLOUR MODIFICATIONS
		766
		767	The following operators change the pixels of the image.
		768
		769	=over 4
		770
		771	=item tint $color, $img
		772
		773	Tints the image in the given colour.
		774
		775	Example: tint the image red.
		776
		777	tint "red", load "rgb.png"
		778
		779	Example: the same, but specify the colour by component.
		780
		781	tint [1, 0, 0], load "rgb.png"
		782
		783	=cut
		784
		785	sub tint($$) {
		786	$_[1]->tint ($_[0])
		787	}
		788
551	=item contrast $factor, $img	789	=item contrast $factor, $img
552		790
553	=item contrast $r, $g, $b, $img	791	=item contrast $r, $g, $b, $img
554		792
555	=item contrast $r, $g, $b, $a, $img	793	=item contrast $r, $g, $b, $a, $img
556		794
557	Adjusts the I<contrast> of an image.	795	Adjusts the I<contrast> of an image.
558		796
559	#TODO#	797	The first form applies a single C<$factor> to red, green and blue, the
		798	second form applies separate factors to each colour channel, and the last
		799	form includes the alpha channel.
560		800
		801	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		802	contrast.
		803
		804	Due to limitations in the underlying XRender extension, lowering contrast
		805	also reduces brightness, while increasing contrast currently also
		806	increases brightness.
		807
561	=item brightness $factor, $img	808	=item brightness $bias, $img
562		809
563	=item brightness $r, $g, $b, $img	810	=item brightness $r, $g, $b, $img
564		811
565	=item brightness $r, $g, $b, $a, $img	812	=item brightness $r, $g, $b, $a, $img
566		813
567	Adjusts the brightness of an image.	814	Adjusts the brightness of an image.
		815
		816	The first form applies a single C<$bias> to red, green and blue, the
		817	second form applies separate biases to each colour channel, and the last
		818	form includes the alpha channel.
		819
		820	Values less than 0 reduce brightness, while values larger than 0 increase
		821	it. Useful range is from -1 to 1 - the former results in a black, the
		822	latter in a white picture.
		823
		824	Due to idiosyncrasies in the underlying XRender extension, biases less
		825	than zero can be I<very> slow.
568		826
569	=cut	827	=cut
570		828
571	sub contrast($$;$$;$) {	829	sub contrast($$;$$;$) {
572	my $img = pop;	830	my $img = pop;
573	my ($r, $g, $b, $a) = @_;	831	my ($r, $g, $b, $a) = @_;
574		832
575	($g, $b) = ($r, $r) if @_ < 4;	833	($g, $b) = ($r, $r) if @_ < 3;
576	$a = 1 if @_ < 5;	834	$a = 1 if @_ < 4;
577		835
578	$img = $img->clone;	836	$img = $img->clone;
579	$img->contrast ($r, $g, $b, $a);	837	$img->contrast ($r, $g, $b, $a);
580	$img	838	$img
581	}	839	}
582		840
583	sub brightness($$;$$;$) {	841	sub brightness($$;$$;$) {
584	my $img = pop;	842	my $img = pop;
585	my ($r, $g, $b, $a) = @_;	843	my ($r, $g, $b, $a) = @_;
586		844
587	($g, $b) = ($r, $r) if @_ < 4;	845	($g, $b) = ($r, $r) if @_ < 3;
588	$a = 1 if @_ < 5;	846	$a = 1 if @_ < 4;
589		847
590	$img = $img->clone;	848	$img = $img->clone;
591	$img->brightness ($r, $g, $b, $a);	849	$img->brightness ($r, $g, $b, $a);
592	$img	850	$img
593	}	851	}
…		…
609	sub blur($$;$) {	867	sub blur($$;$) {
610	my $img = pop;	868	my $img = pop;
611	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	869	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
612	}	870	}
613		871
614	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
615
616	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
617	pointer at C<$center_x> and C<$center_y> (specified as percentage of image
618	width/height), generating a new image with width C<$new_width> and height
619	C<$new_height>.
620
621	#TODO# new width, height, maybe more operators?
622
623	Example: rotate the image by 90 degrees
624
625	=cut
626
627	sub rotate($$$$$$) {
628	my $img = pop;
629	$img->rotate (
630	$_[0],
631	$_[1],
632	$_[2] * $img->w * .01,
633	$_[3] * $img->h * .01,
634	$_[4] * (3.14159265 / 180),
635	)
636	}
637
638	=back	872	=back
639		873
		874	=head2 OTHER STUFF
		875
		876	Anything that didn't fit any of the other categories, even after applying
		877	force and closing our eyes.
		878
		879	=over 4
		880
		881	=item keep { ... }
		882
		883	This operator takes a code block as argument, that is, one or more
		884	statements enclosed by braces.
		885
		886	The trick is that this code block is only evaluated when the outcome
		887	changes - on other calls the C<keep> simply returns the image it computed
		888	previously (yes, it should only be used with images). Or in other words,
		889	C<keep> I<caches> the result of the code block so it doesn't need to be
		890	computed again.
		891
		892	This can be extremely useful to avoid redoing slow operations - for
		893	example, if your background expression takes the root background, blurs it
		894	and then root-aligns it it would have to blur the root background on every
		895	window move or resize.
		896
		897	Another example is C<load>, which can be quite slow.
		898
		899	In fact, urxvt itself encloses the whole expression in some kind of
		900	C<keep> block so it only is reevaluated as required.
		901
		902	Putting the blur into a C<keep> block will make sure the blur is only done
		903	once, while the C<rootalign> is still done each time the window moves.
		904
		905	rootlign keep { blur 10, root }
		906
		907	This leaves the question of how to force reevaluation of the block,
		908	in case the root background changes: If expression inside the block
		909	is sensitive to some event (root background changes, window geometry
		910	changes), then it will be reevaluated automatically as needed.
		911
		912	=cut
		913
		914	sub keep(&) {
		915	my $id = $_[0]+0;
		916
		917	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		918
		919	unless ($frame->[FR_CACHE]) {
		920	$frame->[FR_CACHE] = [ $_[0]() ];
		921
		922	my $self = $self;
		923	my $frame = $frame;
		924	Scalar::Util::weaken $frame;
		925	$self->compile_frame ($frame, sub {
		926	# clear this frame cache, also for all parents
		927	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		928	undef $frame->[FR_CACHE];
		929	}
		930
		931	$self->recalculate;
		932	});
		933	};
		934
		935	# in scalar context we always return the first original result, which
		936	# is not quite how perl works.
		937	wantarray
		938	? @{ $frame->[FR_CACHE] }
		939	: $frame->[FR_CACHE][0]
		940	}
		941
		942	# sub keep_clear() {
		943	# delete $self->{frame_cache};
		944	# }
		945
		946	=back
		947
640	=cut	948	=cut
641		949
642	}	950	}
643		951
644	sub parse_expr {	952	sub parse_expr {
645	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	953	my $expr = eval
		954	"sub {\n"
		955	. "package urxvt::bgdsl;\n"
		956	. "#line 0 'background expression'\n"
		957	. "$_[0]\n"
		958	. "}";
646	die if $@;	959	die if $@;
647	$expr	960	$expr
648	}	961	}
649		962
650	# compiles a parsed expression	963	# compiles a parsed expression
651	sub set_expr {	964	sub set_expr {
652	my ($self, $expr) = @_;	965	my ($self, $expr) = @_;
653		966
		967	$self->{root} = [];
654	$self->{expr} = $expr;	968	$self->{expr} = $expr;
655	$self->recalculate;	969	$self->recalculate;
		970	}
		971
		972	# takes a hash of sensitivity indicators and installs watchers
		973	sub compile_frame {
		974	my ($self, $frame, $cb) = @_;
		975
		976	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		977	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		978
		979	# don't keep stuff alive
		980	Scalar::Util::weaken $state;
		981
		982	if ($again->{nested}) {
		983	$state->{nested} = 1;
		984	} else {
		985	delete $state->{nested};
		986	}
		987
		988	if (my $interval = $again->{time}) {
		989	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		990	if $state->{time}[0] != $interval;
		991
		992	# callback might have changed, although we could just rule that out
		993	$state->{time}[1]->cb (sub {
		994	++$state->{counter};
		995	$cb->();
		996	});
		997	} else {
		998	delete $state->{time};
		999	}
		1000
		1001	if ($again->{position}) {
		1002	$state->{position} = $self->on (position_change => $cb);
		1003	} else {
		1004	delete $state->{position};
		1005	}
		1006
		1007	if ($again->{size}) {
		1008	$state->{size} = $self->on (size_change => $cb);
		1009	} else {
		1010	delete $state->{size};
		1011	}
		1012
		1013	if ($again->{rootpmap}) {
		1014	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		1015	} else {
		1016	delete $state->{rootpmap};
		1017	}
656	}	1018	}
657		1019
658	# evaluate the current bg expression	1020	# evaluate the current bg expression
659	sub recalculate {	1021	sub recalculate {
660	my ($arg_self) = @_;	1022	my ($arg_self) = @_;
…		…
670		1032
671	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1033	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
672		1034
673	# set environment to evaluate user expression	1035	# set environment to evaluate user expression
674		1036
675	local $self = $arg_self;	1037	local $self = $arg_self;
676
677	local $HOME = $ENV{HOME};	1038	local $HOME = $ENV{HOME};
678	local $old = $self->{state};	1039	local $frame = [];
679	local $new = my $state = $self->{state} = {};
680		1040
681	($x, $y, $w, $h) =
682	$self->background_geometry ($self->{border});	1041	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
683		1042
684	# evaluate user expression	1043	# evaluate user expression
685		1044
686	my $img = eval { $self->{expr}->() };	1045	my @img = eval { $self->{expr}->() };
687	warn $@ if $@;#d#	1046	die $@ if $@;
		1047	die "background-expr did not return anything.\n" unless @img;
		1048	die "background-expr: expected image(s), got something else.\n"
688	die if !UNIVERSAL::isa $img, "urxvt::img";	1049	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
689		1050
690	$state->{size_sensitive} = 1	1051	my $img = urxvt::bgdsl::merge @img;
		1052
		1053	$frame->[FR_AGAIN]{size} = 1
691	if $img->repeat_mode != urxvt::RepeatNormal;	1054	if $img->repeat_mode != urxvt::RepeatNormal;
692		1055
693	# if the expression is sensitive to external events, prepare reevaluation then	1056	# if the expression is sensitive to external events, prepare reevaluation then
694		1057	$self->compile_frame ($frame, sub { $arg_self->recalculate });
695	my $repeat;
696
697	if (my $again = $state->{again}) {
698	$repeat = 1;
699	my $self = $self;
700	$state->{timer} = $again == $old->{again}
701	? $old->{timer}
702	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
703	++$self->{counter};
704	$self->recalculate
705	});
706	}
707
708	if (delete $state->{position_sensitive}) {
709	$repeat = 1;
710	$self->enable (position_change => sub { $_[0]->recalculate });
711	} else {
712	$self->disable ("position_change");
713	}
714
715	if (delete $state->{size_sensitive}) {
716	$repeat = 1;
717	$self->enable (size_change => sub { $_[0]->recalculate });
718	} else {
719	$self->disable ("size_change");
720	}
721
722	if (delete $state->{rootpmap_sensitive}) {
723	$repeat = 1;
724	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
725	} else {
726	$self->disable ("rootpmap_change");
727	}
728		1058
729	# clear stuff we no longer need	1059	# clear stuff we no longer need
730		1060
731	%$old = ();	1061	# unless (%{ $frame->[FR_STATE] }) {
732
733	unless ($repeat) {
734	delete $self->{state};	1062	# delete $self->{state};
735	delete $self->{expr};	1063	# delete $self->{expr};
736	}	1064	# }
737		1065
738	# set background pixmap	1066	# set background pixmap
739		1067
740	$self->set_background ($img, $self->{border});	1068	$self->set_background ($img, $self->{border});
741	$self->scr_recolour (0);	1069	$self->scr_recolour (0);
…		…
743	}	1071	}
744		1072
745	sub on_start {	1073	sub on_start {
746	my ($self) = @_;	1074	my ($self) = @_;
747		1075
748	my $expr = $self->x_resource ("background.expr")	1076	my $expr = $self->x_resource ("%.expr")
749	or return;	1077	or return;
750		1078
		1079	$self->has_render
		1080	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1081
751	$self->set_expr (parse_expr $expr);	1082	$self->set_expr (parse_expr $expr);
752	$self->{border} = $self->x_resource_boolean ("background.border");	1083	$self->{border} = $self->x_resource_boolean ("%.border");
		1084
		1085	$MIN_INTERVAL = $self->x_resource ("%.interval");
753		1086
754	()	1087	()
755	}	1088	}
756		1089

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.39 by root, Fri Jun 8 22:19:03 2012 UTC vs. Revision 1.71 by root, Mon Jul 2 01:40:41 2012 UTC

Diff Legend

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.39 by root, Fri Jun 8 22:19:03 2012 UTC vs.
Revision 1.71 by root, Mon Jul 2 01:40:41 2012 UTC