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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.38 by root, Fri Jun 8 21:48:07 2012 UTC vs.
Revision 1.70 by root, Mon Jul 2 01:35:37 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	TODO	123	IF you try out these expressions, you might suffer from some sluggishness,
		124	because each time the terminal is resized, it loads the PNG image agin
		125	and scales it. Scaling is usually fast (and unavoidable), but loading the
		126	image can be quite time consuming. This is where C<keep> comes in handy:
118		127
119	=head3 CYCLES AND CACHING	128	scale 0.5, 2, keep { load "$HOME/mypic.png" }
120		129
121	TODO	130	The C<keep> operator executes all the statements inside the braces only
		131	once, or when it thinks the outcome might change. In other cases it
		132	returns the last value computed by the brace block.
122		133
123	Each time the expression is reevaluated, a new cycle is said to have begun. Many operators	134	This means that the C<load> is only executed once, which makes it much
124	cache their results till the next cycle. For example	135	faster, but also means that more memory is being used, because the loaded
		136	image must be kept in memory at all times. In this expression, the
		137	trade-off is likely worth it.
125		138
		139	But back to effects: Other effects than scaling are also readily
		140	available, for example, you can tile the image to fill the whole window,
		141	instead of resizing it:
		142
		143	tile keep { load "$HOME/mypic.png" }
		144
		145	In fact, images returned by C<load> are in C<tile> mode by default, so the
		146	C<tile> operator is kind of superfluous.
		147
		148	Another common effect is to mirror the image, so that the same edges
		149	touch:
		150
		151	mirror keep { load "$HOME/mypic.png" }
		152
		153	Another common background expression is:
		154
		155	rootalign root
		156
		157	This one first takes a snapshot of the screen background image, and then
		158	moves it to the upper left corner of the screen (as opposed to the upper
		159	left corner of the terminal window)- the result is pseudo-transparency:
		160	the image seems to be static while the window is moved around.
		161
		162	=head2 CACHING AND SENSITIVITY
		163
		164	Since some operations (such as C<load> and C<blur>) can take a long time,
		165	caching results can be very important for a smooth operation. Caching can
		166	also be useful to reduce memory usage, though, for example, when an image
		167	is cached by C<load>, it could be shared by multiple terminal windows
		168	running inside urxvtd.
		169
		170	=head3 C<keep { ... }> caching
		171
		172	The most important way to cache expensive operations is to use C<keep {
		173	... }>. The C<keep> operator takes a block of multiple statements enclosed
		174	by C<{}> and keeps the return value in memory.
		175
		176	An expression can be "sensitive" to various external events, such as
		177	scaling or moving the window, root background changes and timers. Simply
		178	using an expression (such as C<scale> without parameters) that depends on
		179	certain changing values (called "variables"), or using those variables
		180	directly, will make an expression sensitive to these events - for example,
		181	using C<scale> or C<TW> will make the expression sensitive to the terminal
		182	size, and thus to resizing events.
		183
		184	When such an event happens, C<keep> will automatically trigger a
		185	reevaluation of the whole expression with the new value of the expression.
		186
		187	C<keep> is most useful for expensive operations, such as C<blur>:
		188
		189	rootalign keep { blur 20, root }
		190
		191	This makes a blurred copy of the root background once, and on subsequent
		192	calls, just root-aligns it. Since C<blur> is usually quite slow and
		193	C<rootalign> is quite fast, this trades extra memory (for the cached
		194	blurred pixmap) with speed (blur only needs to be redone when root
		195	changes).
		196
		197	=head3 C<load> caching
		198
		199	The C<load> operator itself does not keep images in memory, but as long as
		200	the image is still in memory, C<load> will use the in-memory image instead
		201	of loading it freshly from disk.
		202
		203	That means that this expression:
		204
		205	keep { load "$HOME/path..." }
		206
		207	Not only caches the image in memory, other terminal instances that try to
		208	C<load> it can reuse that in-memory copy.
		209
126	=head2 REFERENCE	210	=head1 REFERENCE
127		211
128	=head3 COMMAND LINE SWITCHES	212	=head2 COMMAND LINE SWITCHES
129		213
130	=over 4	214	=over 4
131		215
132	=item --background-expr perl-expression	216	=item --background-expr perl-expression
133		217
…		…
139	overwriting borders and any other areas, such as the scrollbar.	223	overwriting borders and any other areas, such as the scrollbar.
140		224
141	Specifying this flag changes the behaviour, so that the image only	225	Specifying this flag changes the behaviour, so that the image only
142	replaces the background of the character area.	226	replaces the background of the character area.
143		227
		228	=item --background-interval seconds
		229
		230	Since some operations in the underlying XRender extension can effectively
		231	freeze your X-server for prolonged time, this extension enforces a minimum
		232	time between updates, which is normally about 0.1 seconds.
		233
		234	If you want to do updates more often, you can decrease this safety
		235	interval with this switch.
		236
144	=back	237	=back
145		238
146	=cut	239	=cut
147		240
148	our $EXPR;#d#	241	our %_IMG_CACHE;
149	#$EXPR = 'move W * 0.1, -H * 0.1, resize W * 0.5, H * 0.5, repeat_none load "opensource.png"';
150	$EXPR = 'move -TX, -TY, load "argb.png"';
151	#$EXPR = '
152	# rotate W, H, 50, 50, counter 1/59.95, repeat_mirror,
153	# clip X, Y, W, H, repeat_mirror,
154	# load "/root/pix/das_fette_schwein.jpg"
155	#';
156	#$EXPR = 'solid "red"';
157	#$EXPR = 'blur root, 10, 10'
158	#$EXPR = 'blur move (root, -x, -y), 5, 5'
159	#resize load "/root/pix/das_fette_schwein.jpg", w, h
160
161	our $HOME;	242	our $HOME;
162	our ($self, $old, $new);	243	our ($self, $frame);
163	our ($x, $y, $w, $h);	244	our ($x, $y, $w, $h);
164		245
165	# enforce at least this interval between updates	246	# enforce at least this interval between updates
166	our $MIN_INTERVAL = 1/100;	247	our $MIN_INTERVAL = 6/59.951;
167		248
168	{	249	{
169	package urxvt::bgdsl; # background language	250	package urxvt::bgdsl; # background language
		251
		252	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
		253	sub FR_CACHE () { 1 } # cached values
		254	sub FR_AGAIN () { 2 } # what this expr is sensitive to
		255	sub FR_STATE () { 3 } # watchers etc.
		256
		257	use List::Util qw(min max sum shuffle);
170		258
171	=head2 PROVIDERS/GENERATORS	259	=head2 PROVIDERS/GENERATORS
172		260
173	These functions provide an image, by loading it from disk, grabbing it	261	These functions provide an image, by loading it from disk, grabbing it
174	from the root screen or by simply generating it. They are used as starting	262	from the root screen or by simply generating it. They are used as starting
…		…
179	=item load $path	267	=item load $path
180		268
181	Loads the image at the given C<$path>. The image is set to plane tiling	269	Loads the image at the given C<$path>. The image is set to plane tiling
182	mode.	270	mode.
183		271
184	Loaded images will be cached for one cycle.	272	If the image is already in memory (e.g. because another terminal instance
		273	uses it), then the in-memory copy us returned instead.
		274
		275	=item load_uc $path
		276
		277	Load uncached - same as load, but does not cache the image, which means it
		278	is I<always> loaded from the filesystem again.
185		279
186	=cut	280	=cut
187		281
188	sub load($) {	282	sub load($) {
189	my ($path) = @_;	283	my ($path) = @_;
190		284
191	$new->{load}{$path} = $old->{load}{$path} \|\| $self->new_img_from_file ($path);	285	$_IMG_CACHE{$path} \|\| do {
		286	my $img = $self->new_img_from_file ($path);
		287	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		288	$img
		289	}
192	}	290	}
193		291
194	=item root	292	=item root
195		293
196	Returns the root window pixmap, that is, hopefully, the background image	294	Returns the root window pixmap, that is, hopefully, the background image
197	of your screen. The image is set to extend mode.	295	of your screen.
198		296
199	This function makes your expression root sensitive, that means it will be	297	This function makes your expression root sensitive, that means it will be
200	reevaluated when the bg image changes.	298	reevaluated when the bg image changes.
201		299
202	=cut	300	=cut
203		301
204	sub root() {	302	sub root() {
205	$new->{rootpmap_sensitive} = 1;	303	$frame->[FR_AGAIN]{rootpmap} = 1;
206	die "root op not supported, exg, we need you";	304	$self->new_img_from_root
207	}	305	}
208		306
209	=item solid $colour	307	=item solid $colour
210		308
211	=item solid $width, $height, $colour	309	=item solid $width, $height, $colour
212		310
213	Creates a new image and completely fills it with the given colour. The	311	Creates a new image and completely fills it with the given colour. The
214	image is set to tiling mode.	312	image is set to tiling mode.
215		313
216	If <$width> and C<$height> are omitted, it creates a 1x1 image, which is	314	If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
217	useful for solid backgrounds or for use in filtering effects.	315	useful for solid backgrounds or for use in filtering effects.
218		316
219	=cut	317	=cut
220		318
221	sub solid($$;$) {	319	sub solid($;$$) {
222	my $colour = pop;	320	my $colour = pop;
223		321
224	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	322	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
225	$img->fill ($colour);	323	$img->fill ($colour);
226	$img	324	$img
227	}	325	}
228		326
229	=back	327	=item clone $img
230		328
231	=head2 VARIABLES	329	Returns an exact copy of the image. This is useful if you want to have
		330	multiple copies of the same image to apply different effects to.
232		331
233	The following functions provide variable data such as the terminal
234	window dimensions. Most of them make your expression sensitive to some
235	events, for example using C<TW> (terminal width) means your expression is
236	evaluated again when the terminal is resized.
237
238	=over 4
239
240	=item TX
241
242	=item TY
243
244	Return the X and Y coordinates of the terminal window (the terminal
245	window is the full window by default, and the character area only when in
246	border-respect mode).
247
248	Using these functions make your expression sensitive to window moves.
249
250	These functions are mainly useful to align images to the root window.
251
252	Example: load an image and align it so it looks as if anchored to the
253	background.
254
255	move -TX, -TY, load "mybg.png"
256
257	=item TW
258
259	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
260	terminal window is the full window by default, and the character area only
261	when in border-respect mode).
262
263	Using these functions make your expression sensitive to window resizes.
264
265	These functions are mainly useful to scale images, or to clip images to
266	the window size to conserve memory.
267
268	Example: take the screen background, clip it to the window size, blur it a
269	bit, align it to the window position and use it as background.
270
271	clip move -TX, -TY, blur 5, root
272
273	=cut	332	=cut
274		333
275	sub TX() { $new->{position_sensitive} = 1; $x }
276	sub TY() { $new->{position_sensitive} = 1; $y }
277	sub TW() { $new->{size_sensitive} = 1; $w }
278	sub TH() { $new->{size_sensitive} = 1; $h }
279
280	=item now
281
282	Returns the current time as (fractional) seconds since the epoch.
283
284	Using this expression does I<not> make your expression sensitive to time,
285	but the next two functions do.
286
287	=item again $seconds
288
289	When this function is used the expression will be reevaluated again in
290	C<$seconds> seconds.
291
292	Example: load some image and rotate it according to the time of day (as if it were
293	the hour pointer of a clock). Update this image every minute.
294
295	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
296
297	=item counter $seconds
298
299	Like C<again>, but also returns an increasing counter value, starting at
300	0, which might be useful for some simple animation effects.
301
302	=cut
303
304	sub now() { urxvt::NOW }
305
306	sub again($) {
307	$new->{again} = $_[0];
308	}
309
310	sub counter($) {	334	sub clone($) {
311	$new->{again} = $_[0];	335	$_[0]->clone
312	$self->{counter} + 0
313	}	336	}
314		337
315	=back	338	=item merge $img ...
		339
		340	Takes any number of images and merges them together, creating a single
		341	image containing them all. The tiling mode of the first image is used as
		342	the tiling mode of the resulting image.
		343
		344	This function is called automatically when an expression returns multiple
		345	images.
		346
		347	=cut
		348
		349	sub merge(@) {
		350	return $_[0] unless $#_;
		351
		352	# rather annoyingly clumsy, but optimisation is for another time
		353
		354	my $x0 = +1e9;
		355	my $y0 = +1e9;
		356	my $x1 = -1e9;
		357	my $y1 = -1e9;
		358
		359	for (@_) {
		360	my ($x, $y, $w, $h) = $_->geometry;
		361
		362	$x0 = $x if $x0 > $x;
		363	$y0 = $y if $y0 > $y;
		364
		365	$x += $w;
		366	$y += $h;
		367
		368	$x1 = $x if $x1 < $x;
		369	$y1 = $y if $y1 < $y;
		370	}
		371
		372	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		373	$base->repeat_mode ($_[0]->repeat_mode);
		374	$base->fill ([0, 0, 0, 0]);
		375
		376	$base->draw ($_)
		377	for @_;
		378
		379	$base
		380	}
316		381
317	=head2 TILING MODES	382	=head2 TILING MODES
318		383
319	The following operators modify the tiling mode of an image, that is, the	384	The following operators modify the tiling mode of an image, that is, the
320	way that pixels outside the image area are painted when the image is used.	385	way that pixels outside the image area are painted when the image is used.
…		…
350	become transparent. This mode is most useful when you want to place an	415	become transparent. This mode is most useful when you want to place an
351	image over another image or the background colour while leaving all	416	image over another image or the background colour while leaving all
352	background pixels outside the image unchanged.	417	background pixels outside the image unchanged.
353		418
354	Example: load an image and display it in the upper left corner. The rest	419	Example: load an image and display it in the upper left corner. The rest
355	of the space is left "empty" (transparent or wahtever your compisotr does	420	of the space is left "empty" (transparent or whatever your compositor does
356	in alpha mode, else background colour).	421	in alpha mode, else background colour).
357		422
358	pad load "mybg.png"	423	pad load "mybg.png"
359		424
360	=item extend $img	425	=item extend $img
361		426
362	Extends the image over the whole plane, using the closest pixel in the	427	Extends the image over the whole plane, using the closest pixel in the
363	area outside the image. This mode is mostly useful when you more complex	428	area outside the image. This mode is mostly useful when you use more complex
364	filtering operations and want the pixels outside the image to have the	429	filtering operations and want the pixels outside the image to have the
365	same values as the pixels near the edge.	430	same values as the pixels near the edge.
366		431
367	Example: just for curiosity, how does this pixel extension stuff work?	432	Example: just for curiosity, how does this pixel extension stuff work?
368		433
…		…
394	$img	459	$img
395	}	460	}
396		461
397	=back	462	=back
398		463
399	=head2 PIXEL OPERATORS	464	=head2 VARIABLE VALUES
400		465
401	The following operators modify the image pixels in various ways.	466	The following functions provide variable data such as the terminal window
		467	dimensions. They are not (Perl-) variables, they just return stuff that
		468	varies. Most of them make your expression sensitive to some events, for
		469	example using C<TW> (terminal width) means your expression is evaluated
		470	again when the terminal is resized.
402		471
403	=over 4	472	=over 4
404		473
405	=item clone $img	474	=item TX
406		475
407	Returns an exact copy of the image.	476	=item TY
408		477
409	=cut	478	Return the X and Y coordinates of the terminal window (the terminal
		479	window is the full window by default, and the character area only when in
		480	border-respect mode).
410		481
		482	Using these functions make your expression sensitive to window moves.
		483
		484	These functions are mainly useful to align images to the root window.
		485
		486	Example: load an image and align it so it looks as if anchored to the
		487	background (that's exactly what C<rootalign> does btw.):
		488
		489	move -TX, -TY, keep { load "mybg.png" }
		490
		491	=item TW
		492
		493	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		494	terminal window is the full window by default, and the character area only
		495	when in border-respect mode).
		496
		497	Using these functions make your expression sensitive to window resizes.
		498
		499	These functions are mainly useful to scale images, or to clip images to
		500	the window size to conserve memory.
		501
		502	Example: take the screen background, clip it to the window size, blur it a
		503	bit, align it to the window position and use it as background.
		504
		505	clip move -TX, -TY, keep { blur 5, root }
		506
		507	=cut
		508
		509	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
		510	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
		511	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
		512	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
		513
		514	=item now
		515
		516	Returns the current time as (fractional) seconds since the epoch.
		517
		518	Using this expression does I<not> make your expression sensitive to time,
		519	but the next two functions do.
		520
		521	=item again $seconds
		522
		523	When this function is used the expression will be reevaluated again in
		524	C<$seconds> seconds.
		525
		526	Example: load some image and rotate it according to the time of day (as if it were
		527	the hour pointer of a clock). Update this image every minute.
		528
		529	again 60;
		530	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
		531
		532	=item counter $seconds
		533
		534	Like C<again>, but also returns an increasing counter value, starting at
		535	0, which might be useful for some simple animation effects.
		536
		537	=cut
		538
		539	sub now() { urxvt::NOW }
		540
		541	sub again($) {
		542	$frame->[FR_AGAIN]{time} = $_[0];
		543	}
		544
411	sub clone($) {	545	sub counter($) {
412	$_[0]->clone	546	$frame->[FR_AGAIN]{time} = $_[0];
		547	$frame->[FR_STATE]{counter} + 0
413	}	548	}
		549
		550	=back
		551
		552	=head2 SHAPE CHANGING OPERATORS
		553
		554	The following operators modify the shape, size or position of the image.
		555
		556	=over 4
414		557
415	=item clip $img	558	=item clip $img
416		559
417	=item clip $width, $height, $img	560	=item clip $width, $height, $img
418		561
…		…
429	assumed.	572	assumed.
430		573
431	Example: load an image, blur it, and clip it to the window size to save	574	Example: load an image, blur it, and clip it to the window size to save
432	memory.	575	memory.
433		576
434	clip blur 10, load "mybg.png"	577	clip keep { blur 10, load "mybg.png" }
435		578
436	=cut	579	=cut
437		580
438	sub clip($;$$;$$) {	581	sub clip($;$$;$$) {
439	my $img = pop;	582	my $img = pop;
…		…
442	$img->sub_rect ($_[0], $_[1], $w, $h)	585	$img->sub_rect ($_[0], $_[1], $w, $h)
443	}	586	}
444		587
445	=item scale $img	588	=item scale $img
446		589
447	=item scale $size_percent, $img	590	=item scale $size_factor, $img
448		591
449	=item scale $width_percent, $height_percent, $img	592	=item scale $width_factor, $height_factor, $img
450		593
451	Scales the image by the given percentages in horizontal	594	Scales the image by the given factors in horizontal
452	(C<$width_percent>) and vertical (C<$height_percent>) direction.	595	(C<$width>) and vertical (C<$height>) direction.
453		596
454	If only one percentage is give, it is used for both directions.	597	If only one factor is give, it is used for both directions.
455		598
456	If no percentages are given, scales the image to the window size without	599	If no factors are given, scales the image to the window size without
457	keeping aspect.	600	keeping aspect.
458		601
459	=item resize $width, $height, $img	602	=item resize $width, $height, $img
460		603
461	Resizes the image to exactly C<$width> times C<$height> pixels.	604	Resizes the image to exactly C<$width> times C<$height> pixels.
462		605
463	=cut	606	=item fit $img
464		607
465	#TODO: maximise, maximise_fill?	608	=item fit $width, $height, $img
		609
		610	Fits the image into the given C<$width> and C<$height> without changing
		611	aspect, or the terminal size. That means it will be shrunk or grown until
		612	the whole image fits into the given area, possibly leaving borders.
		613
		614	=item cover $img
		615
		616	=item cover $width, $height, $img
		617
		618	Similar to C<fit>, but shrinks or grows until all of the area is covered
		619	by the image, so instead of potentially leaving borders, it will cut off
		620	image data that doesn't fit.
		621
		622	=cut
466		623
467	sub scale($;$;$) {	624	sub scale($;$;$) {
468	my $img = pop;	625	my $img = pop;
469		626
470	@_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01)	627	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
471	: @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01)	628	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
472	: $img->scale (TW, TH)	629	: $img->scale (TW, TH)
473	}	630	}
474		631
475	sub resize($$$) {	632	sub resize($$$) {
476	my $img = pop;	633	my $img = pop;
477	$img->scale ($_[0], $_[1])	634	$img->scale ($_[0], $_[1])
478	}	635	}
479		636
		637	sub fit($;$$) {
		638	my $img = pop;
		639	my $w = ($_[0] \|\| TW) / $img->w;
		640	my $h = ($_[1] \|\| TH) / $img->h;
		641	scale +(min $w, $h), $img
		642	}
		643
		644	sub cover($;$$) {
		645	my $img = pop;
		646	my $w = ($_[0] \|\| TW) / $img->w;
		647	my $h = ($_[1] \|\| TH) / $img->h;
		648	scale +(max $w, $h), $img
		649	}
		650
480	=item move $dx, $dy, $img	651	=item move $dx, $dy, $img
481		652
482	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in	653	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
483	the vertical.	654	the vertical.
484		655
485	Example: move the image right by 20 pixels and down by 30.	656	Example: move the image right by 20 pixels and down by 30.
486		657
487	move 20, 30, ...	658	move 20, 30, ...
		659
		660	=item align $xalign, $yalign, $img
		661
		662	Aligns the image according to a factor - C<0> means the image is moved to
		663	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		664	exactly centered and C<1> means it touches the right or bottom edge.
		665
		666	Example: remove any visible border around an image, center it vertically but move
		667	it to the right hand side.
		668
		669	align 1, 0.5, pad $img
		670
		671	=item center $img
		672
		673	=item center $width, $height, $img
		674
		675	Centers the image, i.e. the center of the image is moved to the center of
		676	the terminal window (or the box specified by C<$width> and C<$height> if
		677	given).
		678
		679	Example: load an image and center it.
		680
		681	center keep { pad load "mybg.png" }
488		682
489	=item rootalign $img	683	=item rootalign $img
490		684
491	Moves the image so that it appears glued to the screen as opposed to the	685	Moves the image so that it appears glued to the screen as opposed to the
492	window. This gives the illusion of a larger area behind the window. It is	686	window. This gives the illusion of a larger area behind the window. It is
493	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	687	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
494	top left of the screen.	688	top left of the screen.
495		689
496	Example: load a background image, put it in mirror mode and root align it.	690	Example: load a background image, put it in mirror mode and root align it.
497		691
498	rootalign mirror load "mybg.png"	692	rootalign keep { mirror load "mybg.png" }
499		693
500	Example: take the screen background and align it, giving the illusion of	694	Example: take the screen background and align it, giving the illusion of
501	transparency as long as the window isn't in front of other windows.	695	transparency as long as the window isn't in front of other windows.
502		696
503	rootalign root	697	rootalign root
504		698
505	=cut	699	=cut
506		700
507	sub move($$;$) {	701	sub move($$;$) {
508	my $img = pop->clone;	702	my $img = pop->clone;
509	$img->move ($_[0], $_[1]);	703	$img->move ($_[0], $_[1]);
510	$img	704	$img
511	}	705	}
512		706
		707	sub align($;$$) {
		708	my $img = pop;
		709
		710	move $_[0] * (TW - $img->w),
		711	$_[1] * (TH - $img->h),
		712	$img
		713	}
		714
		715	sub center($;$$) {
		716	my $img = pop;
		717	my $w = $_[0] \|\| TW;
		718	my $h = $_[1] \|\| TH;
		719
		720	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		721	}
		722
513	sub rootalign($) {	723	sub rootalign($) {
514	move -TX, -TY, $_[0]	724	move -TX, -TY, $_[0]
515	}	725	}
516		726
		727	=item rotate $center_x, $center_y, $degrees, $img
		728
		729	Rotates the image clockwise by C<$degrees> degrees, around the point at
		730	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		731
		732	Example: rotate the image by 90 degrees around it's center.
		733
		734	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		735
		736	=cut
		737
		738	sub rotate($$$$) {
		739	my $img = pop;
		740	$img->rotate (
		741	$_[0] * ($img->w + $img->x),
		742	$_[1] * ($img->h + $img->y),
		743	$_[2] * (3.14159265 / 180),
		744	)
		745	}
		746
		747	=back
		748
		749	=head2 COLOUR MODIFICATIONS
		750
		751	The following operators change the pixels of the image.
		752
		753	=over 4
		754
		755	=item tint $color, $img
		756
		757	Tints the image in the given colour.
		758
		759	Example: tint the image red.
		760
		761	tint "red", load "rgb.png"
		762
		763	Example: the same, but specify the colour by component.
		764
		765	tint [1, 0, 0], load "rgb.png"
		766
		767	=cut
		768
		769	sub tint($$) {
		770	$_[1]->tint ($_[0])
		771	}
		772
517	=item contrast $factor, $img	773	=item contrast $factor, $img
518		774
519	=item contrast $r, $g, $b, $img	775	=item contrast $r, $g, $b, $img
520		776
521	=item contrast $r, $g, $b, $a, $img	777	=item contrast $r, $g, $b, $a, $img
522		778
523	Adjusts the I<contrast> of an image.	779	Adjusts the I<contrast> of an image.
524		780
525	#TODO#	781	The first form applies a single C<$factor> to red, green and blue, the
		782	second form applies separate factors to each colour channel, and the last
		783	form includes the alpha channel.
526		784
		785	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		786	contrast.
		787
		788	Due to limitations in the underlying XRender extension, lowering contrast
		789	also reduces brightness, while increasing contrast currently also
		790	increases brightness.
		791
527	=item brightness $factor, $img	792	=item brightness $bias, $img
528		793
529	=item brightness $r, $g, $b, $img	794	=item brightness $r, $g, $b, $img
530		795
531	=item brightness $r, $g, $b, $a, $img	796	=item brightness $r, $g, $b, $a, $img
532		797
533	Adjusts the brightness of an image.	798	Adjusts the brightness of an image.
		799
		800	The first form applies a single C<$bias> to red, green and blue, the
		801	second form applies separate biases to each colour channel, and the last
		802	form includes the alpha channel.
		803
		804	Values less than 0 reduce brightness, while values larger than 0 increase
		805	it. Useful range is from -1 to 1 - the former results in a black, the
		806	latter in a white picture.
		807
		808	Due to idiosyncrasies in the underlying XRender extension, biases less
		809	than zero can be I<very> slow.
534		810
535	=cut	811	=cut
536		812
537	sub contrast($$;$$;$) {	813	sub contrast($$;$$;$) {
538	my $img = pop;	814	my $img = pop;
539	my ($r, $g, $b, $a) = @_;	815	my ($r, $g, $b, $a) = @_;
540		816
541	($g, $b) = ($r, $r) if @_ < 4;	817	($g, $b) = ($r, $r) if @_ < 3;
542	$a = 1 if @_ < 5;	818	$a = 1 if @_ < 4;
543		819
544	$img = $img->clone;	820	$img = $img->clone;
545	$img->contrast ($r, $g, $b, $a);	821	$img->contrast ($r, $g, $b, $a);
546	$img	822	$img
547	}	823	}
548		824
549	sub brightness($$;$$;$) {	825	sub brightness($$;$$;$) {
550	my $img = pop;	826	my $img = pop;
551	my ($r, $g, $b, $a) = @_;	827	my ($r, $g, $b, $a) = @_;
552		828
553	($g, $b) = ($r, $r) if @_ < 4;	829	($g, $b) = ($r, $r) if @_ < 3;
554	$a = 1 if @_ < 5;	830	$a = 1 if @_ < 4;
555		831
556	$img = $img->clone;	832	$img = $img->clone;
557	$img->brightness ($r, $g, $b, $a);	833	$img->brightness ($r, $g, $b, $a);
558	$img	834	$img
559	}	835	}
…		…
563	=item blur $radius_horz, $radius_vert, $img	839	=item blur $radius_horz, $radius_vert, $img
564		840
565	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii	841	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
566	can also be specified separately.	842	can also be specified separately.
567		843
		844	Blurring is often I<very> slow, at least compared or other
		845	operators. Larger blur radii are slower than smaller ones, too, so if you
		846	don't want to freeze your screen for long times, start experimenting with
		847	low values for radius (<5).
		848
568	=cut	849	=cut
569		850
570	sub blur($$;$) {	851	sub blur($$;$) {
571	my $img = pop;	852	my $img = pop;
572	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	853	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
573	}	854	}
574		855
575	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
576
577	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
578	pointer at C<$center_x> and C<$center_y> (specified as percentage of image
579	width/height), generating a new image with width C<$new_width> and height
580	C<$new_height>.
581
582	#TODO# new width, height, maybe more operators?
583
584	Example: rotate the image by 90 degrees
585
586	=cut
587
588	sub rotate($$$$$$) {
589	my $img = pop;
590	$img->rotate (
591	$_[0],
592	$_[1],
593	$_[2] * $img->w * .01,
594	$_[3] * $img->h * .01,
595	$_[4] * (3.14159265 / 180),
596	)
597	}
598
599	=back	856	=back
600		857
		858	=head2 OTHER STUFF
		859
		860	Anything that didn't fit any of the other categories, even after applying
		861	force and closing our eyes.
		862
		863	=over 4
		864
		865	=item keep { ... }
		866
		867	This operator takes a code block as argument, that is, one or more
		868	statements enclosed by braces.
		869
		870	The trick is that this code block is only evaluated when the outcome
		871	changes - on other calls the C<keep> simply returns the image it computed
		872	previously (yes, it should only be used with images). Or in other words,
		873	C<keep> I<caches> the result of the code block so it doesn't need to be
		874	computed again.
		875
		876	This can be extremely useful to avoid redoing slow operations - for
		877	example, if your background expression takes the root background, blurs it
		878	and then root-aligns it it would have to blur the root background on every
		879	window move or resize.
		880
		881	Another example is C<load>, which can be quite slow.
		882
		883	In fact, urxvt itself encloses the whole expression in some kind of
		884	C<keep> block so it only is reevaluated as required.
		885
		886	Putting the blur into a C<keep> block will make sure the blur is only done
		887	once, while the C<rootalign> is still done each time the window moves.
		888
		889	rootlign keep { blur 10, root }
		890
		891	This leaves the question of how to force reevaluation of the block,
		892	in case the root background changes: If expression inside the block
		893	is sensitive to some event (root background changes, window geometry
		894	changes), then it will be reevaluated automatically as needed.
		895
		896	=cut
		897
		898	sub keep(&) {
		899	my $id = $_[0]+0;
		900
		901	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		902
		903	unless ($frame->[FR_CACHE]) {
		904	$frame->[FR_CACHE] = [ $_[0]() ];
		905
		906	my $self = $self;
		907	my $frame = $frame;
		908	Scalar::Util::weaken $frame;
		909	$self->compile_frame ($frame, sub {
		910	# clear this frame cache, also for all parents
		911	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		912	undef $frame->[FR_CACHE];
		913	}
		914
		915	$self->recalculate;
		916	});
		917	};
		918
		919	# in scalar context we always return the first original result, which
		920	# is not quite how perl works.
		921	wantarray
		922	? @{ $frame->[FR_CACHE] }
		923	: $frame->[FR_CACHE][0]
		924	}
		925
		926	# sub keep_clear() {
		927	# delete $self->{frame_cache};
		928	# }
		929
		930	=back
		931
601	=cut	932	=cut
602		933
603	}	934	}
604		935
605	sub parse_expr {	936	sub parse_expr {
606	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	937	my $expr = eval
		938	"sub {\n"
		939	. "package urxvt::bgdsl;\n"
		940	. "#line 0 'background expression'\n"
		941	. "$_[0]\n"
		942	. "}";
607	die if $@;	943	die if $@;
608	$expr	944	$expr
609	}	945	}
610		946
611	# compiles a parsed expression	947	# compiles a parsed expression
612	sub set_expr {	948	sub set_expr {
613	my ($self, $expr) = @_;	949	my ($self, $expr) = @_;
614		950
		951	$self->{root} = [];
615	$self->{expr} = $expr;	952	$self->{expr} = $expr;
616	$self->recalculate;	953	$self->recalculate;
		954	}
		955
		956	# takes a hash of sensitivity indicators and installs watchers
		957	sub compile_frame {
		958	my ($self, $frame, $cb) = @_;
		959
		960	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		961	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		962
		963	# don't keep stuff alive
		964	Scalar::Util::weaken $state;
		965
		966	if ($again->{nested}) {
		967	$state->{nested} = 1;
		968	} else {
		969	delete $state->{nested};
		970	}
		971
		972	if (my $interval = $again->{time}) {
		973	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		974	if $state->{time}[0] != $interval;
		975
		976	# callback might have changed, although we could just rule that out
		977	$state->{time}[1]->cb (sub {
		978	++$state->{counter};
		979	$cb->();
		980	});
		981	} else {
		982	delete $state->{time};
		983	}
		984
		985	if ($again->{position}) {
		986	$state->{position} = $self->on (position_change => $cb);
		987	} else {
		988	delete $state->{position};
		989	}
		990
		991	if ($again->{size}) {
		992	$state->{size} = $self->on (size_change => $cb);
		993	} else {
		994	delete $state->{size};
		995	}
		996
		997	if ($again->{rootpmap}) {
		998	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		999	} else {
		1000	delete $state->{rootpmap};
		1001	}
617	}	1002	}
618		1003
619	# evaluate the current bg expression	1004	# evaluate the current bg expression
620	sub recalculate {	1005	sub recalculate {
621	my ($arg_self) = @_;	1006	my ($arg_self) = @_;
…		…
631		1016
632	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1017	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
633		1018
634	# set environment to evaluate user expression	1019	# set environment to evaluate user expression
635		1020
636	local $self = $arg_self;	1021	local $self = $arg_self;
637
638	local $HOME = $ENV{HOME};	1022	local $HOME = $ENV{HOME};
639	local $old = $self->{state};	1023	local $frame = [];
640	local $new = my $state = $self->{state} = {};
641		1024
642	($x, $y, $w, $h) =
643	$self->background_geometry ($self->{border});	1025	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
644		1026
645	# evaluate user expression	1027	# evaluate user expression
646		1028
647	my $img = eval { $self->{expr}->() };	1029	my @img = eval { $self->{expr}->() };
648	warn $@ if $@;#d#	1030	die $@ if $@;
		1031	die "background-expr did not return anything.\n" unless @img;
		1032	die "background-expr: expected image(s), got something else.\n"
649	die if !UNIVERSAL::isa $img, "urxvt::img";	1033	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
650		1034
651	$state->{size_sensitive} = 1	1035	my $img = urxvt::bgdsl::merge @img;
		1036
		1037	$frame->[FR_AGAIN]{size} = 1
652	if $img->repeat_mode != urxvt::RepeatNormal;	1038	if $img->repeat_mode != urxvt::RepeatNormal;
653		1039
654	# if the expression is sensitive to external events, prepare reevaluation then	1040	# if the expression is sensitive to external events, prepare reevaluation then
655		1041	$self->compile_frame ($frame, sub { $arg_self->recalculate });
656	my $repeat;
657
658	if (my $again = $state->{again}) {
659	$repeat = 1;
660	my $self = $self;
661	$state->{timer} = $again == $old->{again}
662	? $old->{timer}
663	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
664	++$self->{counter};
665	$self->recalculate
666	});
667	}
668
669	if (delete $state->{position_sensitive}) {
670	$repeat = 1;
671	$self->enable (position_change => sub { $_[0]->recalculate });
672	} else {
673	$self->disable ("position_change");
674	}
675
676	if (delete $state->{size_sensitive}) {
677	$repeat = 1;
678	$self->enable (size_change => sub { $_[0]->recalculate });
679	} else {
680	$self->disable ("size_change");
681	}
682
683	if (delete $state->{rootpmap_sensitive}) {
684	$repeat = 1;
685	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
686	} else {
687	$self->disable ("rootpmap_change");
688	}
689		1042
690	# clear stuff we no longer need	1043	# clear stuff we no longer need
691		1044
692	%$old = ();	1045	# unless (%{ $frame->[FR_STATE] }) {
693
694	unless ($repeat) {
695	delete $self->{state};	1046	# delete $self->{state};
696	delete $self->{expr};	1047	# delete $self->{expr};
697	}	1048	# }
698		1049
699	# set background pixmap	1050	# set background pixmap
700		1051
701	$self->set_background ($img, $self->{border});	1052	$self->set_background ($img, $self->{border});
702	$self->scr_recolour (0);	1053	$self->scr_recolour (0);
…		…
704	}	1055	}
705		1056
706	sub on_start {	1057	sub on_start {
707	my ($self) = @_;	1058	my ($self) = @_;
708		1059
709	my $expr = $self->x_resource ("background.expr")	1060	my $expr = $self->x_resource ("%.expr")
710	or return;	1061	or return;
711		1062
		1063	$self->has_render
		1064	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1065
712	$self->set_expr (parse_expr $expr);	1066	$self->set_expr (parse_expr $expr);
713	$self->{border} = $self->x_resource_boolean ("background.border");	1067	$self->{border} = $self->x_resource_boolean ("%.border");
		1068
		1069	$MIN_INTERVAL = $self->x_resource ("%.interval");
714		1070
715	()	1071	()
716	}	1072	}
717		1073

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.38 by root, Fri Jun 8 21:48:07 2012 UTC vs. Revision 1.70 by root, Mon Jul 2 01:35:37 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.38 by root, Fri Jun 8 21:48:07 2012 UTC vs.
Revision 1.70 by root, Mon Jul 2 01:35:37 2012 UTC