[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 1.57 by root, Thu Jun 14 18:06:15 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
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 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.
…		…
55		57
56	For example, an expression such as C<scale load "$HOME/mybg.png"> scales the	58	For example, an expression such as C<scale load "$HOME/mybg.png"> scales the
57	image to the window size, so it relies on the window size and will	59	image to the window size, so it relies on the window size and will
58	be reevaluated each time it is changed, but not when it moves for	60	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
67	again 3600;	69	again 3600;
…		…
69	return scale load "$HOME/weekday.png";	71	return scale load "$HOME/weekday.png";
70	} else {	72	} else {
71	return scale load "$HOME/sunday.png";	73	return scale load "$HOME/sunday.png";
72	}	74	}
73		75
74	This expression gets evaluated once per hour. It will set F<sunday.png> as	76	This expression is evaluated once per hour. It will set F<sunday.png> as
75	background on Sundays, and F<weekday.png> on all other days.	77	background on Sundays, and F<weekday.png> on all other days.
76		78
77	Fortunately, we expect that most expressions will be much simpler, with	79	Fortunately, we expect that most expressions will be much simpler, with
78	little Perl knowledge needed.	80	little Perl knowledge needed.
79		81
…		…
97	its result becomes the argument to the C<scale> function.	99	its result becomes the argument to the C<scale> function.
98		100
99	Many operators also allow some parameters preceding the input image	101	Many operators also allow some parameters preceding the input image
100	that modify its behaviour. For example, C<scale> without any additional	102	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	103	arguments scales the image to size of the terminal window. If you specify
102	an additional argument, it uses it as a percentage:	104	an additional argument, it uses it as a scale factor (multiply by 100 to
		105	get a percentage):
103		106
104	scale 200, load "$HOME/mypic.png"	107	scale 2, load "$HOME/mypic.png"
105		108
106	This enlarges the image by a factor of 2 (200%). As you can see, C<scale>	109	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	110	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	111	C<load> only has one argument. Arguments are separated from each other by
109	commas.	112	commas.
110		113
111	Scale also accepts two arguments, which are then separate factors for both	114	Scale also accepts two arguments, which are then separate factors for both
112	horizontal and vertical dimensions. For example, this halves the image	115	horizontal and vertical dimensions. For example, this halves the image
113	width and doubles the image height:	116	width and doubles the image height:
114		117
115	scale 50, 200, load "$HOME/mypic.png"	118	scale 0.5, 2, load "$HOME/mypic.png"
116		119
117	Other effects than scalign are also readily available, for exmaple, you can	120	Other effects than scaling are also readily available, for example, you can
118	tile the image to fill the whole window, instead of resizing it:	121	tile the image to fill the whole window, instead of resizing it:
119		122
120	tile load "$HOME/mypic.png"	123	tile load "$HOME/mypic.png"
121		124
122	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator	125	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator
…		…
133	It first takes a snapshot of the screen background image, and then	136	It 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	137	moves it to the upper left corner of the screen - the result is
135	pseudo-transparency, as the image seems to be static while the window is	138	pseudo-transparency, as the image seems to be static while the window is
136	moved around.	139	moved around.
137		140
138	=head3 CYCLES AND CACHING	141	=head2 CYCLES AND CACHING
139		142
140	As has been mentioned before, the expression might be evaluated multiple	143	As has been mentioned before, the expression might be evaluated multiple
141	times. Each time the expression is reevaluated, a new cycle is said to	144	times. Each time the expression is reevaluated, a new cycle is said to
142	have begun. Many operators cache their results till the next cycle.	145	have begun. Many operators cache their results till the next cycle.
143		146
…		…
148	This only works for one cycle though, so as long as you load the same	151	This only works for one cycle though, so as long as you load the same
149	image every time, it will always be cached, but when you load a different	152	image every time, it will always be cached, but when you load a different
150	image, it will forget about the first one.	153	image, it will forget about the first one.
151		154
152	This allows you to either speed things up by keeping multiple images in	155	This allows you to either speed things up by keeping multiple images in
153	memory, or comserve memory by loading images more often.	156	memory, or conserve memory by loading images more often.
154		157
155	For example, you can keep two images in memory and use a random one like	158	For example, you can keep two images in memory and use a random one like
156	this:	159	this:
157		160
158	my $img1 = load "img1.png";	161	my $img1 = load "img1.png";
…		…
168		171
169	Here, a path is selected randomly, and load is only called for one image,	172	Here, a path is selected randomly, and load is only called for one image,
170	so keeps only one image in memory. If, on the next evaluation, luck	173	so keeps only one image in memory. If, on the next evaluation, luck
171	decides to use the other path, then it will have to load that image again.	174	decides to use the other path, then it will have to load that image again.
172		175
173	=head2 REFERENCE	176	=head1 REFERENCE
174		177
175	=head3 COMMAND LINE SWITCHES	178	=head2 COMMAND LINE SWITCHES
176		179
177	=over 4	180	=over 4
178		181
179	=item --background-expr perl-expression	182	=item --background-expr perl-expression
180		183
…		…
186	overwriting borders and any other areas, such as the scrollbar.	189	overwriting borders and any other areas, such as the scrollbar.
187		190
188	Specifying this flag changes the behaviour, so that the image only	191	Specifying this flag changes the behaviour, so that the image only
189	replaces the background of the character area.	192	replaces the background of the character area.
190		193
		194	=item --background-interval seconds
		195
		196	Since some operations in the underlying XRender extension can effectively
		197	freeze your X-server for prolonged time, this extension enforces a minimum
		198	time between updates, which is normally about 0.1 seconds.
		199
		200	If you want to do updates more often, you can decrease this safety
		201	interval with this switch.
		202
191	=back	203	=back
192		204
193	=cut	205	=cut
194		206
		207	our %_IMG_CACHE;
195	our $HOME;	208	our $HOME;
196	our ($self, $old, $new);	209	our ($self, $old, $new);
197	our ($x, $y, $w, $h);	210	our ($x, $y, $w, $h);
198		211
199	# enforce at least this interval between updates	212	# enforce at least this interval between updates
200	our $MIN_INTERVAL = 1/100;	213	our $MIN_INTERVAL = 6/59.951;
201		214
202	{	215	{
203	package urxvt::bgdsl; # background language	216	package urxvt::bgdsl; # background language
		217
		218	use List::Util qw(min max sum shuffle);
204		219
205	=head2 PROVIDERS/GENERATORS	220	=head2 PROVIDERS/GENERATORS
206		221
207	These functions provide an image, by loading it from disk, grabbing it	222	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	223	from the root screen or by simply generating it. They are used as starting
…		…
213	=item load $path	228	=item load $path
214		229
215	Loads the image at the given C<$path>. The image is set to plane tiling	230	Loads the image at the given C<$path>. The image is set to plane tiling
216	mode.	231	mode.
217		232
218	Loaded images will be cached for one cycle.	233	Loaded images will be cached for one cycle, and shared between temrinals
		234	running in the same process (e.g. in C<urxvtd>).
219		235
		236	=item load_uc $path
		237
		238	Load uncached - same as load, but does not cache the image. This function
		239	is most useufl if you want to optimise a background expression in some
		240	way.
		241
220	=cut	242	=cut
		243
		244	sub load_uc($) {
		245	my ($path) = @_;
		246
		247	$_IMG_CACHE{$path} \|\| do {
		248	my $img = $self->new_img_from_file ($path);
		249	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		250	$img
		251	}
		252	}
221		253
222	sub load($) {	254	sub load($) {
223	my ($path) = @_;	255	my ($path) = @_;
224		256
225	$new->{load}{$path} = $old->{load}{$path} \|\| $self->new_img_from_file ($path);	257	$new->{load}{$path} = $old->{load}{$path} \|\| load_uc $path;
226	}	258	}
227		259
228	=item root	260	=item root
229		261
230	Returns the root window pixmap, that is, hopefully, the background image	262	Returns the root window pixmap, that is, hopefully, the background image
…		…
234	reevaluated when the bg image changes.	266	reevaluated when the bg image changes.
235		267
236	=cut	268	=cut
237		269
238	sub root() {	270	sub root() {
239	$new->{rootpmap_sensitive} = 1;	271	$new->{again}{rootpmap} = 1;
240	die "root op not supported, exg, we need you";	272	$self->new_img_from_root
241	}	273	}
242		274
243	=item solid $colour	275	=item solid $colour
244		276
245	=item solid $width, $height, $colour	277	=item solid $width, $height, $colour
246		278
247	Creates a new image and completely fills it with the given colour. The	279	Creates a new image and completely fills it with the given colour. The
248	image is set to tiling mode.	280	image is set to tiling mode.
249		281
250	If <$width> and C<$height> are omitted, it creates a 1x1 image, which is	282	If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
251	useful for solid backgrounds or for use in filtering effects.	283	useful for solid backgrounds or for use in filtering effects.
252		284
253	=cut	285	=cut
254		286
255	sub solid($$;$) {	287	sub solid($;$$) {
256	my $colour = pop;	288	my $colour = pop;
257		289
258	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	290	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);
259	$img->fill ($colour);	291	$img->fill ($colour);
260	$img	292	$img
261	}	293	}
262		294
263	=back	295	=item clone $img
264		296
265	=head2 VARIABLES	297	Returns an exact copy of the image. This is useful if you want to have
		298	multiple copies of the same image to apply different effects to.
266		299
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	300	=cut
308		301
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} = $_[0];
342	}
343
344	sub counter($) {	302	sub clone($) {
345	$new->{again} = $_[0];	303	$_[0]->clone
346	$self->{counter} + 0
347	}	304	}
348		305
349	=back	306	=item merge $img ...
		307
		308	Takes any number of images and merges them together, creating a single
		309	image containing them all.
		310
		311	=cut
		312
		313	sub merge(@) {
		314	#TODO
		315	}
350		316
351	=head2 TILING MODES	317	=head2 TILING MODES
352		318
353	The following operators modify the tiling mode of an image, that is, the	319	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.	320	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	350	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	351	image over another image or the background colour while leaving all
386	background pixels outside the image unchanged.	352	background pixels outside the image unchanged.
387		353
388	Example: load an image and display it in the upper left corner. The rest	354	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	355	of the space is left "empty" (transparent or whatever your compositor does
390	in alpha mode, else background colour).	356	in alpha mode, else background colour).
391		357
392	pad load "mybg.png"	358	pad load "mybg.png"
393		359
394	=item extend $img	360	=item extend $img
395		361
396	Extends the image over the whole plane, using the closest pixel in the	362	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	363	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	364	filtering operations and want the pixels outside the image to have the
399	same values as the pixels near the edge.	365	same values as the pixels near the edge.
400		366
401	Example: just for curiosity, how does this pixel extension stuff work?	367	Example: just for curiosity, how does this pixel extension stuff work?
402		368
…		…
428	$img	394	$img
429	}	395	}
430		396
431	=back	397	=back
432		398
433	=head2 PIXEL OPERATORS	399	=head2 VARIABLE VALUES
434		400
435	The following operators modify the image pixels in various ways.	401	The following functions provide variable data such as the terminal window
		402	dimensions. They are not (Perl-) variables, they just return stuff that
		403	varies. Most of them make your expression sensitive to some events, for
		404	example using C<TW> (terminal width) means your expression is evaluated
		405	again when the terminal is resized.
436		406
437	=over 4	407	=over 4
438		408
439	=item clone $img	409	=item TX
440		410
441	Returns an exact copy of the image.	411	=item TY
442		412
443	=cut	413	Return the X and Y coordinates of the terminal window (the terminal
		414	window is the full window by default, and the character area only when in
		415	border-respect mode).
444		416
		417	Using these functions make your expression sensitive to window moves.
		418
		419	These functions are mainly useful to align images to the root window.
		420
		421	Example: load an image and align it so it looks as if anchored to the
		422	background.
		423
		424	move -TX, -TY, load "mybg.png"
		425
		426	=item TW
		427
		428	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		429	terminal window is the full window by default, and the character area only
		430	when in border-respect mode).
		431
		432	Using these functions make your expression sensitive to window resizes.
		433
		434	These functions are mainly useful to scale images, or to clip images to
		435	the window size to conserve memory.
		436
		437	Example: take the screen background, clip it to the window size, blur it a
		438	bit, align it to the window position and use it as background.
		439
		440	clip move -TX, -TY, once { blur 5, root }
		441
		442	=cut
		443
		444	sub TX() { $new->{again}{position} = 1; $x }
		445	sub TY() { $new->{again}{position} = 1; $y }
		446	sub TW() { $new->{again}{size} = 1; $w }
		447	sub TH() { $new->{again}{size} = 1; $h }
		448
		449	=item now
		450
		451	Returns the current time as (fractional) seconds since the epoch.
		452
		453	Using this expression does I<not> make your expression sensitive to time,
		454	but the next two functions do.
		455
		456	=item again $seconds
		457
		458	When this function is used the expression will be reevaluated again in
		459	C<$seconds> seconds.
		460
		461	Example: load some image and rotate it according to the time of day (as if it were
		462	the hour pointer of a clock). Update this image every minute.
		463
		464	again 60; rotate 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
		465
		466	=item counter $seconds
		467
		468	Like C<again>, but also returns an increasing counter value, starting at
		469	0, which might be useful for some simple animation effects.
		470
		471	=cut
		472
		473	sub now() { urxvt::NOW }
		474
		475	sub again($) {
		476	$new->{again}{time} = $_[0];
		477	}
		478
445	sub clone($) {	479	sub counter($) {
446	$_[0]->clone	480	$new->{again}{time} = $_[0];
		481	$self->{counter} + 0
447	}	482	}
		483
		484	=back
		485
		486	=head2 SHAPE CHANGING OPERATORS
		487
		488	The following operators modify the shape, size or position of the image.
		489
		490	=over 4
448		491
449	=item clip $img	492	=item clip $img
450		493
451	=item clip $width, $height, $img	494	=item clip $width, $height, $img
452		495
…		…
476	$img->sub_rect ($_[0], $_[1], $w, $h)	519	$img->sub_rect ($_[0], $_[1], $w, $h)
477	}	520	}
478		521
479	=item scale $img	522	=item scale $img
480		523
481	=item scale $size_percent, $img	524	=item scale $size_factor, $img
482		525
483	=item scale $width_percent, $height_percent, $img	526	=item scale $width_factor, $height_factor, $img
484		527
485	Scales the image by the given percentages in horizontal	528	Scales the image by the given factors in horizontal
486	(C<$width_percent>) and vertical (C<$height_percent>) direction.	529	(C<$width>) and vertical (C<$height>) direction.
487		530
488	If only one percentage is give, it is used for both directions.	531	If only one factor is give, it is used for both directions.
489		532
490	If no percentages are given, scales the image to the window size without	533	If no factors are given, scales the image to the window size without
491	keeping aspect.	534	keeping aspect.
492		535
493	=item resize $width, $height, $img	536	=item resize $width, $height, $img
494		537
495	Resizes the image to exactly C<$width> times C<$height> pixels.	538	Resizes the image to exactly C<$width> times C<$height> pixels.
496		539
497	=cut	540	=item fit $img
498		541
499	#TODO: maximise, maximise_fill?	542	=item fit $width, $height, $img
		543
		544	Fits the image into the given C<$width> and C<$height> without changing
		545	aspect, or the terminal size. That means it will be shrunk or grown until
		546	the whole image fits into the given area, possibly leaving borders.
		547
		548	=item cover $img
		549
		550	=item cover $width, $height, $img
		551
		552	Similar to C<fit>, but shrinks or grows until all of the area is covered
		553	by the image, so instead of potentially leaving borders, it will cut off
		554	image data that doesn't fit.
		555
		556	=cut
500		557
501	sub scale($;$;$) {	558	sub scale($;$;$) {
502	my $img = pop;	559	my $img = pop;
503		560
504	@_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01)	561	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
505	: @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01)	562	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
506	: $img->scale (TW, TH)	563	: $img->scale (TW, TH)
507	}	564	}
508		565
509	sub resize($$$) {	566	sub resize($$$) {
510	my $img = pop;	567	my $img = pop;
511	$img->scale ($_[0], $_[1])	568	$img->scale ($_[0], $_[1])
		569	}
		570
		571	sub fit($;$$) {
		572	my $img = pop;
		573	my $w = ($_[0] \|\| TW) / $img->w;
		574	my $h = ($_[1] \|\| TH) / $img->h;
		575	scale +(min $w, $h), $img
		576	}
		577
		578	sub cover($;$$) {
		579	my $img = pop;
		580	my $w = ($_[0] \|\| TW) / $img->w;
		581	my $h = ($_[1] \|\| TH) / $img->h;
		582	scale +(max $w, $h), $img
512	}	583	}
513		584
514	=item move $dx, $dy, $img	585	=item move $dx, $dy, $img
515		586
516	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in	587	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
517	the vertical.	588	the vertical.
518		589
519	Example: move the image right by 20 pixels and down by 30.	590	Example: move the image right by 20 pixels and down by 30.
520		591
521	move 20, 30, ...	592	move 20, 30, ...
		593
		594	=item align $xalign, $yalign, $img
		595
		596	Aligns the image according to a factor - C<0> means the image is moved to
		597	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		598	exactly centered and C<1> means it touches the right or bottom edge.
		599
		600	Example: remove any visible border around an image, center it vertically but move
		601	it to the right hand side.
		602
		603	align 1, 0.5, pad $img
		604
		605	=item center $img
		606
		607	=item center $width, $height, $img
		608
		609	Centers the image, i.e. the center of the image is moved to the center of
		610	the terminal window (or the box specified by C<$width> and C<$height> if
		611	given).
		612
		613	Example: load an image and center it.
		614
		615	center pad load "mybg.png"
522		616
523	=item rootalign $img	617	=item rootalign $img
524		618
525	Moves the image so that it appears glued to the screen as opposed to the	619	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	620	window. This gives the illusion of a larger area behind the window. It is
…		…
532	rootalign mirror load "mybg.png"	626	rootalign mirror load "mybg.png"
533		627
534	Example: take the screen background and align it, giving the illusion of	628	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.	629	transparency as long as the window isn't in front of other windows.
536		630
537	rootalign root	631	rootalign root
538		632
539	=cut	633	=cut
540		634
541	sub move($$;$) {	635	sub move($$;$) {
542	my $img = pop->clone;	636	my $img = pop->clone;
543	$img->move ($_[0], $_[1]);	637	$img->move ($_[0], $_[1]);
544	$img	638	$img
545	}	639	}
546		640
		641	sub align($;$$) {
		642	my $img = pop;
		643
		644	move $_[0] * (TW - $img->w),
		645	$_[1] * (TH - $img->h),
		646	$img
		647	}
		648
		649	sub center($;$$) {
		650	my $img = pop;
		651	my $w = $_[0] \|\| TW;
		652	my $h = $_[1] \|\| TH;
		653
		654	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		655	}
		656
547	sub rootalign($) {	657	sub rootalign($) {
548	move -TX, -TY, $_[0]	658	move -TX, -TY, $_[0]
549	}	659	}
550		660
		661	=item rotate $center_x, $center_y, $degrees
		662
		663	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
		664	pointer at C<$center_x> and C<$center_y> (specified as factor of image
		665	width/height).
		666
		667	#TODO# new width, height, maybe more operators?
		668
		669	Example: rotate the image by 90 degrees
		670
		671	=cut
		672
		673	sub rotate($$$$) {
		674	my $img = pop;
		675	$img->rotate (
		676	$_[0] * $img->w,
		677	$_[1] * $img->h,
		678	$_[2] * (3.14159265 / 180),
		679	)
		680	}
		681
		682	=back
		683
		684	=head2 COLOUR MODIFICATIONS
		685
		686	The following operators change the pixels of the image.
		687
		688	=over 4
		689
551	=item contrast $factor, $img	690	=item contrast $factor, $img
552		691
553	=item contrast $r, $g, $b, $img	692	=item contrast $r, $g, $b, $img
554		693
555	=item contrast $r, $g, $b, $a, $img	694	=item contrast $r, $g, $b, $a, $img
556		695
557	Adjusts the I<contrast> of an image.	696	Adjusts the I<contrast> of an image.
558		697
559	#TODO#	698	The first form applies a single C<$factor> to red, green and blue, the
		699	second form applies separate factors to each colour channel, and the last
		700	form includes the alpha channel.
560		701
		702	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		703	contrast.
		704
		705	Due to limitations in the underlying XRender extension, lowering contrast
		706	also reduces brightness, while increasing contrast currently also
		707	increases brightness.
		708
561	=item brightness $factor, $img	709	=item brightness $bias, $img
562		710
563	=item brightness $r, $g, $b, $img	711	=item brightness $r, $g, $b, $img
564		712
565	=item brightness $r, $g, $b, $a, $img	713	=item brightness $r, $g, $b, $a, $img
566		714
567	Adjusts the brightness of an image.	715	Adjusts the brightness of an image.
568		716
		717	The first form applies a single C<$bias> to red, green and blue, the
		718	second form applies separate biases to each colour channel, and the last
		719	form includes the alpha channel.
		720
		721	Values less than 0 reduce brightness, while values larger than 0 increase
		722	it. Useful range is from -1 to 1 - the former results in a black, the
		723	latter in a white picture.
		724
		725	Due to idiosyncrasies in the underlying XRender extension, biases less
		726	than zero can be I<very> slow.
		727
569	=cut	728	=cut
570		729
571	sub contrast($$;$$;$) {	730	sub contrast($$;$$;$) {
572	my $img = pop;	731	my $img = pop;
573	my ($r, $g, $b, $a) = @_;	732	my ($r, $g, $b, $a) = @_;
574		733
575	($g, $b) = ($r, $r) if @_ < 4;	734	($g, $b) = ($r, $r) if @_ < 3;
576	$a = 1 if @_ < 5;	735	$a = 1 if @_ < 4;
577		736
578	$img = $img->clone;	737	$img = $img->clone;
579	$img->contrast ($r, $g, $b, $a);	738	$img->contrast ($r, $g, $b, $a);
580	$img	739	$img
581	}	740	}
582		741
583	sub brightness($$;$$;$) {	742	sub brightness($$;$$;$) {
584	my $img = pop;	743	my $img = pop;
585	my ($r, $g, $b, $a) = @_;	744	my ($r, $g, $b, $a) = @_;
586		745
587	($g, $b) = ($r, $r) if @_ < 4;	746	($g, $b) = ($r, $r) if @_ < 3;
588	$a = 1 if @_ < 5;	747	$a = 1 if @_ < 4;
589		748
590	$img = $img->clone;	749	$img = $img->clone;
591	$img->brightness ($r, $g, $b, $a);	750	$img->brightness ($r, $g, $b, $a);
592	$img	751	$img
593	}	752	}
…		…
609	sub blur($$;$) {	768	sub blur($$;$) {
610	my $img = pop;	769	my $img = pop;
611	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	770	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
612	}	771	}
613		772
614	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees	773	=back
615		774
616	Rotates the image by C<$degrees> degrees, counter-clockwise, around the	775	=head2 OTHER STUFF
617	pointer at C<$center_x> and C<$center_y> (specified as percentage of image
618	width/height), generating a new image with width C<$new_width> and height
619	C<$new_height>.
620		776
621	#TODO# new width, height, maybe more operators?	777	Anything that didn't fit any of the other categories, even after applying
		778	force and closing our eyes.
622		779
623	Example: rotate the image by 90 degrees	780	=over 4
624		781
625	=cut	782	=item once { ... }
626		783
627	sub rotate($$$$$$) {	784	This function takes a code block as argument, that is, one or more
628	my $img = pop;	785	statements enclosed by braces.
629	$img->rotate (	786
630	$_[0],	787	The trick is that this code block is only evaluated once - future calls
631	$_[1],	788	will simply return the original image (yes, it should only be used with
632	$_[2] * $img->w * .01,	789	images).
633	$_[3] * $img->h * .01,	790
634	$_[4] * (3.14159265 / 180),	791	This can be extremely useful to avoid redoign the same slow operations
		792	again and again- for example, if your background expression takes the root
		793	background, blurs it and then root-aligns it it would have to blur the
		794	root background on every window move or resize.
		795
		796	Putting the blur into a C<once> block will make sure the blur is only done
		797	once:
		798
		799	rootlign once { blur 10, root }
		800
		801	This leaves the question of how to force reevaluation of the block, in
		802	case the root background changes: Right now, all once blocks forget that
		803	they ahve been executed before each time the root background changes (if
		804	the expression is sensitive to that) or when C<once_again> is called.
		805
		806	=item once_again
		807
		808	Resets all C<once> block as if they had never been called, i.e. on the
		809	next call they will be reevaluated again.
		810
		811	=cut
		812
		813	sub once(&) {
		814	my $once = $self->{once_cache}{$_[0]+0} \|\|= do {
		815	local $new->{again};
		816	my @res = $_[0]();
		817	[$new->{again}, \@res]
635	)	818	};
		819
		820	$new->{again} = {
		821	%{ $new->{again} },
		822	%{ $once->[0] }
		823	};
		824
		825	# in scalar context we always return the first original result, which
		826	# is not quite how perl works.
		827	wantarray
		828	? @{ $once->[1] }
		829	: $once->[1][0]
		830	}
		831
		832	sub once_again() {
		833	delete $self->{once_cache};
636	}	834	}
637		835
638	=back	836	=back
639		837
640	=cut	838	=cut
…		…
683		881
684	# evaluate user expression	882	# evaluate user expression
685		883
686	my $img = eval { $self->{expr}->() };	884	my $img = eval { $self->{expr}->() };
687	warn $@ if $@;#d#	885	warn $@ if $@;#d#
688	die if !UNIVERSAL::isa $img, "urxvt::img";	886	die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";
689		887
690	$state->{size_sensitive} = 1	888	# if the expression is sensitive to external events, prepare reevaluation then
		889
		890	my $again = delete $state->{again};
		891
		892	$again->{size} = 1
691	if $img->repeat_mode != urxvt::RepeatNormal;	893	if $img->repeat_mode != urxvt::RepeatNormal;
692		894
693	# if the expression is sensitive to external events, prepare reevaluation then
694
695	my $repeat;
696
697	if (my $again = $state->{again}) {	895	if (my $again = $again->{time}) {
698	$repeat = 1;
699	my $self = $self;	896	my $self = $self;
700	$state->{timer} = $again == $old->{again}	897	$state->{timer} = $again == $old->{again}
701	? $old->{timer}	898	? $old->{timer}
702	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {	899	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
703	++$self->{counter};	900	++$self->{counter};
704	$self->recalculate	901	$self->recalculate
705	});	902	});
706	}	903	}
707		904
708	if (delete $state->{position_sensitive}) {	905	if ($again->{position}) {
709	$repeat = 1;
710	$self->enable (position_change => sub { $_[0]->recalculate });	906	$self->enable (position_change => sub { $_[0]->recalculate });
711	} else {	907	} else {
712	$self->disable ("position_change");	908	$self->disable ("position_change");
713	}	909	}
714		910
715	if (delete $state->{size_sensitive}) {	911	if ($again->{size}) {
716	$repeat = 1;
717	$self->enable (size_change => sub { $_[0]->recalculate });	912	$self->enable (size_change => sub { $_[0]->recalculate });
718	} else {	913	} else {
719	$self->disable ("size_change");	914	$self->disable ("size_change");
720	}	915	}
721		916
722	if (delete $state->{rootpmap_sensitive}) {	917	if ($again->{rootpmap}) {
723	$repeat = 1;
724	$self->enable (rootpmap_change => sub { $_[0]->recalculate });	918	$self->enable (rootpmap_change => sub {
		919	delete $_[0]{once_cache}; # this will override once-block values from
		920	$_[0]->recalculate;
		921	});
725	} else {	922	} else {
726	$self->disable ("rootpmap_change");	923	$self->disable ("rootpmap_change");
727	}	924	}
728		925
729	# clear stuff we no longer need	926	# clear stuff we no longer need
730		927
731	%$old = ();	928	%$old = ();
732		929
733	unless ($repeat) {	930	unless (%$again) {
734	delete $self->{state};	931	delete $self->{state};
735	delete $self->{expr};	932	delete $self->{expr};
736	}	933	}
737		934
738	# set background pixmap	935	# set background pixmap
…		…
743	}	940	}
744		941
745	sub on_start {	942	sub on_start {
746	my ($self) = @_;	943	my ($self) = @_;
747		944
748	my $expr = $self->x_resource ("background.expr")	945	my $expr = $self->x_resource ("%.expr")
749	or return;	946	or return;
750		947
		948	$self->has_render
		949	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		950
751	$self->set_expr (parse_expr $expr);	951	$self->set_expr (parse_expr $expr);
752	$self->{border} = $self->x_resource_boolean ("background.border");	952	$self->{border} = $self->x_resource_boolean ("%.border");
		953
		954	$MIN_INTERVAL = $self->x_resource ("%.interval");
753		955
754	()	956	()
755	}	957	}
756		958

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.39 by root, Fri Jun 8 22:19:03 2012 UTC vs. Revision 1.57 by root, Thu Jun 14 18:06:15 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.39 by root, Fri Jun 8 22:19:03 2012 UTC vs.
Revision 1.57 by root, Thu Jun 14 18:06:15 2012 UTC