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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.40 by root, Fri Jun 8 22:19:21 2012 UTC vs.
Revision 1.61 by root, Fri Jun 15 19:50:56 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, $colour
…		…
250	If C<$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, 0, $_[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	This function is called automatically when an expression returns multiple
		312	images.
		313
		314	=cut
		315
		316	sub merge(@) {
		317	return $_[0] unless $#_;
		318
		319	# rather annoyingly clumsy, but optimisation is for another time
		320
		321	my $x0 = +1e9;
		322	my $y0 = +1e9;
		323	my $x1 = -1e9;
		324	my $y1 = -1e9;
		325
		326	for (@_) {
		327	my ($x, $y, $w, $h) = $_->geometry;
		328
		329	$x0 = $x if $x0 > $x;
		330	$y0 = $y if $y0 > $y;
		331
		332	$x += $w;
		333	$y += $h;
		334
		335	$x1 = $x if $x1 < $x;
		336	$y1 = $y if $y1 < $y;
		337	}
		338
		339	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		340	$base->fill ([0, 0, 0, 0]);
		341
		342	$base->draw ($_)
		343	for @_;
		344
		345	$base
		346	}
350		347
351	=head2 TILING MODES	348	=head2 TILING MODES
352		349
353	The following operators modify the tiling mode of an image, that is, the	350	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.	351	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	381	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	382	image over another image or the background colour while leaving all
386	background pixels outside the image unchanged.	383	background pixels outside the image unchanged.
387		384
388	Example: load an image and display it in the upper left corner. The rest	385	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	386	of the space is left "empty" (transparent or whatever your compositor does
390	in alpha mode, else background colour).	387	in alpha mode, else background colour).
391		388
392	pad load "mybg.png"	389	pad load "mybg.png"
393		390
394	=item extend $img	391	=item extend $img
395		392
396	Extends the image over the whole plane, using the closest pixel in the	393	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	394	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	395	filtering operations and want the pixels outside the image to have the
399	same values as the pixels near the edge.	396	same values as the pixels near the edge.
400		397
401	Example: just for curiosity, how does this pixel extension stuff work?	398	Example: just for curiosity, how does this pixel extension stuff work?
402		399
…		…
428	$img	425	$img
429	}	426	}
430		427
431	=back	428	=back
432		429
433	=head2 PIXEL OPERATORS	430	=head2 VARIABLE VALUES
434		431
435	The following operators modify the image pixels in various ways.	432	The following functions provide variable data such as the terminal window
		433	dimensions. They are not (Perl-) variables, they just return stuff that
		434	varies. Most of them make your expression sensitive to some events, for
		435	example using C<TW> (terminal width) means your expression is evaluated
		436	again when the terminal is resized.
436		437
437	=over 4	438	=over 4
438		439
439	=item clone $img	440	=item TX
440		441
441	Returns an exact copy of the image.	442	=item TY
442		443
443	=cut	444	Return the X and Y coordinates of the terminal window (the terminal
		445	window is the full window by default, and the character area only when in
		446	border-respect mode).
444		447
		448	Using these functions make your expression sensitive to window moves.
		449
		450	These functions are mainly useful to align images to the root window.
		451
		452	Example: load an image and align it so it looks as if anchored to the
		453	background.
		454
		455	move -TX, -TY, load "mybg.png"
		456
		457	=item TW
		458
		459	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		460	terminal window is the full window by default, and the character area only
		461	when in border-respect mode).
		462
		463	Using these functions make your expression sensitive to window resizes.
		464
		465	These functions are mainly useful to scale images, or to clip images to
		466	the window size to conserve memory.
		467
		468	Example: take the screen background, clip it to the window size, blur it a
		469	bit, align it to the window position and use it as background.
		470
		471	clip move -TX, -TY, once { blur 5, root }
		472
		473	=cut
		474
		475	sub TX() { $new->{again}{position} = 1; $x }
		476	sub TY() { $new->{again}{position} = 1; $y }
		477	sub TW() { $new->{again}{size} = 1; $w }
		478	sub TH() { $new->{again}{size} = 1; $h }
		479
		480	=item now
		481
		482	Returns the current time as (fractional) seconds since the epoch.
		483
		484	Using this expression does I<not> make your expression sensitive to time,
		485	but the next two functions do.
		486
		487	=item again $seconds
		488
		489	When this function is used the expression will be reevaluated again in
		490	C<$seconds> seconds.
		491
		492	Example: load some image and rotate it according to the time of day (as if it were
		493	the hour pointer of a clock). Update this image every minute.
		494
		495	again 60; rotate 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
		496
		497	=item counter $seconds
		498
		499	Like C<again>, but also returns an increasing counter value, starting at
		500	0, which might be useful for some simple animation effects.
		501
		502	=cut
		503
		504	sub now() { urxvt::NOW }
		505
		506	sub again($) {
		507	$new->{again}{time} = $_[0];
		508	}
		509
445	sub clone($) {	510	sub counter($) {
446	$_[0]->clone	511	$new->{again}{time} = $_[0];
		512	$self->{counter} + 0
447	}	513	}
		514
		515	=back
		516
		517	=head2 SHAPE CHANGING OPERATORS
		518
		519	The following operators modify the shape, size or position of the image.
		520
		521	=over 4
448		522
449	=item clip $img	523	=item clip $img
450		524
451	=item clip $width, $height, $img	525	=item clip $width, $height, $img
452		526
…		…
476	$img->sub_rect ($_[0], $_[1], $w, $h)	550	$img->sub_rect ($_[0], $_[1], $w, $h)
477	}	551	}
478		552
479	=item scale $img	553	=item scale $img
480		554
481	=item scale $size_percent, $img	555	=item scale $size_factor, $img
482		556
483	=item scale $width_percent, $height_percent, $img	557	=item scale $width_factor, $height_factor, $img
484		558
485	Scales the image by the given percentages in horizontal	559	Scales the image by the given factors in horizontal
486	(C<$width_percent>) and vertical (C<$height_percent>) direction.	560	(C<$width>) and vertical (C<$height>) direction.
487		561
488	If only one percentage is give, it is used for both directions.	562	If only one factor is give, it is used for both directions.
489		563
490	If no percentages are given, scales the image to the window size without	564	If no factors are given, scales the image to the window size without
491	keeping aspect.	565	keeping aspect.
492		566
493	=item resize $width, $height, $img	567	=item resize $width, $height, $img
494		568
495	Resizes the image to exactly C<$width> times C<$height> pixels.	569	Resizes the image to exactly C<$width> times C<$height> pixels.
496		570
497	=cut	571	=item fit $img
498		572
499	#TODO: maximise, maximise_fill?	573	=item fit $width, $height, $img
		574
		575	Fits the image into the given C<$width> and C<$height> without changing
		576	aspect, or the terminal size. That means it will be shrunk or grown until
		577	the whole image fits into the given area, possibly leaving borders.
		578
		579	=item cover $img
		580
		581	=item cover $width, $height, $img
		582
		583	Similar to C<fit>, but shrinks or grows until all of the area is covered
		584	by the image, so instead of potentially leaving borders, it will cut off
		585	image data that doesn't fit.
		586
		587	=cut
500		588
501	sub scale($;$;$) {	589	sub scale($;$;$) {
502	my $img = pop;	590	my $img = pop;
503		591
504	@_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01)	592	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
505	: @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01)	593	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
506	: $img->scale (TW, TH)	594	: $img->scale (TW, TH)
507	}	595	}
508		596
509	sub resize($$$) {	597	sub resize($$$) {
510	my $img = pop;	598	my $img = pop;
511	$img->scale ($_[0], $_[1])	599	$img->scale ($_[0], $_[1])
		600	}
		601
		602	sub fit($;$$) {
		603	my $img = pop;
		604	my $w = ($_[0] \|\| TW) / $img->w;
		605	my $h = ($_[1] \|\| TH) / $img->h;
		606	scale +(min $w, $h), $img
		607	}
		608
		609	sub cover($;$$) {
		610	my $img = pop;
		611	my $w = ($_[0] \|\| TW) / $img->w;
		612	my $h = ($_[1] \|\| TH) / $img->h;
		613	scale +(max $w, $h), $img
512	}	614	}
513		615
514	=item move $dx, $dy, $img	616	=item move $dx, $dy, $img
515		617
516	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in	618	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
517	the vertical.	619	the vertical.
518		620
519	Example: move the image right by 20 pixels and down by 30.	621	Example: move the image right by 20 pixels and down by 30.
520		622
521	move 20, 30, ...	623	move 20, 30, ...
		624
		625	=item align $xalign, $yalign, $img
		626
		627	Aligns the image according to a factor - C<0> means the image is moved to
		628	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		629	exactly centered and C<1> means it touches the right or bottom edge.
		630
		631	Example: remove any visible border around an image, center it vertically but move
		632	it to the right hand side.
		633
		634	align 1, 0.5, pad $img
		635
		636	=item center $img
		637
		638	=item center $width, $height, $img
		639
		640	Centers the image, i.e. the center of the image is moved to the center of
		641	the terminal window (or the box specified by C<$width> and C<$height> if
		642	given).
		643
		644	Example: load an image and center it.
		645
		646	center pad load "mybg.png"
522		647
523	=item rootalign $img	648	=item rootalign $img
524		649
525	Moves the image so that it appears glued to the screen as opposed to the	650	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	651	window. This gives the illusion of a larger area behind the window. It is
…		…
532	rootalign mirror load "mybg.png"	657	rootalign mirror load "mybg.png"
533		658
534	Example: take the screen background and align it, giving the illusion of	659	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.	660	transparency as long as the window isn't in front of other windows.
536		661
537	rootalign root	662	rootalign root
538		663
539	=cut	664	=cut
540		665
541	sub move($$;$) {	666	sub move($$;$) {
542	my $img = pop->clone;	667	my $img = pop->clone;
543	$img->move ($_[0], $_[1]);	668	$img->move ($_[0], $_[1]);
544	$img	669	$img
545	}	670	}
546		671
		672	sub align($;$$) {
		673	my $img = pop;
		674
		675	move $_[0] * (TW - $img->w),
		676	$_[1] * (TH - $img->h),
		677	$img
		678	}
		679
		680	sub center($;$$) {
		681	my $img = pop;
		682	my $w = $_[0] \|\| TW;
		683	my $h = $_[1] \|\| TH;
		684
		685	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		686	}
		687
547	sub rootalign($) {	688	sub rootalign($) {
548	move -TX, -TY, $_[0]	689	move -TX, -TY, $_[0]
549	}	690	}
550		691
		692	=item rotate $center_x, $center_y, $degrees
		693
		694	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
		695	pointer at C<$center_x> and C<$center_y> (specified as factor of image
		696	width/height).
		697
		698	#TODO# new width, height, maybe more operators?
		699
		700	Example: rotate the image by 90 degrees
		701
		702	=cut
		703
		704	sub rotate($$$$) {
		705	my $img = pop;
		706	$img->rotate (
		707	$_[0] * ($img->w + $img->x),
		708	$_[1] * ($img->h + $img->y),
		709	$_[2] * (3.14159265 / 180),
		710	)
		711	}
		712
		713	=back
		714
		715	=head2 COLOUR MODIFICATIONS
		716
		717	The following operators change the pixels of the image.
		718
		719	=over 4
		720
551	=item contrast $factor, $img	721	=item contrast $factor, $img
552		722
553	=item contrast $r, $g, $b, $img	723	=item contrast $r, $g, $b, $img
554		724
555	=item contrast $r, $g, $b, $a, $img	725	=item contrast $r, $g, $b, $a, $img
556		726
557	Adjusts the I<contrast> of an image.	727	Adjusts the I<contrast> of an image.
558		728
559	#TODO#	729	The first form applies a single C<$factor> to red, green and blue, the
		730	second form applies separate factors to each colour channel, and the last
		731	form includes the alpha channel.
560		732
		733	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		734	contrast.
		735
		736	Due to limitations in the underlying XRender extension, lowering contrast
		737	also reduces brightness, while increasing contrast currently also
		738	increases brightness.
		739
561	=item brightness $factor, $img	740	=item brightness $bias, $img
562		741
563	=item brightness $r, $g, $b, $img	742	=item brightness $r, $g, $b, $img
564		743
565	=item brightness $r, $g, $b, $a, $img	744	=item brightness $r, $g, $b, $a, $img
566		745
567	Adjusts the brightness of an image.	746	Adjusts the brightness of an image.
568		747
		748	The first form applies a single C<$bias> to red, green and blue, the
		749	second form applies separate biases to each colour channel, and the last
		750	form includes the alpha channel.
		751
		752	Values less than 0 reduce brightness, while values larger than 0 increase
		753	it. Useful range is from -1 to 1 - the former results in a black, the
		754	latter in a white picture.
		755
		756	Due to idiosyncrasies in the underlying XRender extension, biases less
		757	than zero can be I<very> slow.
		758
569	=cut	759	=cut
570		760
571	sub contrast($$;$$;$) {	761	sub contrast($$;$$;$) {
572	my $img = pop;	762	my $img = pop;
573	my ($r, $g, $b, $a) = @_;	763	my ($r, $g, $b, $a) = @_;
574		764
575	($g, $b) = ($r, $r) if @_ < 4;	765	($g, $b) = ($r, $r) if @_ < 3;
576	$a = 1 if @_ < 5;	766	$a = 1 if @_ < 4;
577		767
578	$img = $img->clone;	768	$img = $img->clone;
579	$img->contrast ($r, $g, $b, $a);	769	$img->contrast ($r, $g, $b, $a);
580	$img	770	$img
581	}	771	}
582		772
583	sub brightness($$;$$;$) {	773	sub brightness($$;$$;$) {
584	my $img = pop;	774	my $img = pop;
585	my ($r, $g, $b, $a) = @_;	775	my ($r, $g, $b, $a) = @_;
586		776
587	($g, $b) = ($r, $r) if @_ < 4;	777	($g, $b) = ($r, $r) if @_ < 3;
588	$a = 1 if @_ < 5;	778	$a = 1 if @_ < 4;
589		779
590	$img = $img->clone;	780	$img = $img->clone;
591	$img->brightness ($r, $g, $b, $a);	781	$img->brightness ($r, $g, $b, $a);
592	$img	782	$img
593	}	783	}
…		…
609	sub blur($$;$) {	799	sub blur($$;$) {
610	my $img = pop;	800	my $img = pop;
611	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	801	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
612	}	802	}
613		803
614	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees	804	=back
615		805
616	Rotates the image by C<$degrees> degrees, counter-clockwise, around the	806	=head2 OTHER STUFF
617	pointer at C<$center_x> and C<$center_y> (specified as percentage of image
618	width/height), generating a new image with width C<$new_width> and height
619	C<$new_height>.
620		807
621	#TODO# new width, height, maybe more operators?	808	Anything that didn't fit any of the other categories, even after applying
		809	force and closing our eyes.
622		810
623	Example: rotate the image by 90 degrees	811	=over 4
624		812
625	=cut	813	=item once { ... }
626		814
627	sub rotate($$$$$$) {	815	This function takes a code block as argument, that is, one or more
628	my $img = pop;	816	statements enclosed by braces.
629	$img->rotate (	817
630	$_[0],	818	The trick is that this code block is only evaluated once - future calls
631	$_[1],	819	will simply return the original image (yes, it should only be used with
632	$_[2] * $img->w * .01,	820	images).
633	$_[3] * $img->h * .01,	821
634	$_[4] * (3.14159265 / 180),	822	This can be extremely useful to avoid redoign the same slow operations
		823	again and again- for example, if your background expression takes the root
		824	background, blurs it and then root-aligns it it would have to blur the
		825	root background on every window move or resize.
		826
		827	Putting the blur into a C<once> block will make sure the blur is only done
		828	once:
		829
		830	rootlign once { blur 10, root }
		831
		832	This leaves the question of how to force reevaluation of the block, in
		833	case the root background changes: Right now, all once blocks forget that
		834	they ahve been executed before each time the root background changes (if
		835	the expression is sensitive to that) or when C<once_again> is called.
		836
		837	=item once_again
		838
		839	Resets all C<once> block as if they had never been called, i.e. on the
		840	next call they will be reevaluated again.
		841
		842	=cut
		843
		844	sub once(&) {
		845	my $once = $self->{once_cache}{$_[0]+0} \|\|= do {
		846	local $new->{again};
		847	my @res = $_[0]();
		848	[$new->{again}, \@res]
635	)	849	};
		850
		851	$new->{again} = {
		852	%{ $new->{again} },
		853	%{ $once->[0] }
		854	};
		855
		856	# in scalar context we always return the first original result, which
		857	# is not quite how perl works.
		858	wantarray
		859	? @{ $once->[1] }
		860	: $once->[1][0]
		861	}
		862
		863	sub once_again() {
		864	delete $self->{once_cache};
636	}	865	}
637		866
638	=back	867	=back
639		868
640	=cut	869	=cut
…		…
681	($x, $y, $w, $h) =	910	($x, $y, $w, $h) =
682	$self->background_geometry ($self->{border});	911	$self->background_geometry ($self->{border});
683		912
684	# evaluate user expression	913	# evaluate user expression
685		914
686	my $img = eval { $self->{expr}->() };	915	my $img = eval { urxvt::bgdsl::merge $self->{expr}->() };
687	warn $@ if $@;#d#	916	die $@ if $@;
688	die if !UNIVERSAL::isa $img, "urxvt::img";	917	die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";
689		918
690	$state->{size_sensitive} = 1	919	# if the expression is sensitive to external events, prepare reevaluation then
		920
		921	my $again = delete $state->{again};
		922
		923	$again->{size} = 1
691	if $img->repeat_mode != urxvt::RepeatNormal;	924	if $img->repeat_mode != urxvt::RepeatNormal;
692		925
693	# if the expression is sensitive to external events, prepare reevaluation then
694
695	my $repeat;
696
697	if (my $again = $state->{again}) {	926	if (my $again = $again->{time}) {
698	$repeat = 1;
699	my $self = $self;	927	my $self = $self;
700	$state->{timer} = $again == $old->{again}	928	$state->{timer} = $again == $old->{again}
701	? $old->{timer}	929	? $old->{timer}
702	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {	930	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
703	++$self->{counter};	931	++$self->{counter};
704	$self->recalculate	932	$self->recalculate
705	});	933	});
706	}	934	}
707		935
708	if (delete $state->{position_sensitive}) {	936	if ($again->{position}) {
709	$repeat = 1;
710	$self->enable (position_change => sub { $_[0]->recalculate });	937	$self->enable (position_change => sub { $_[0]->recalculate });
711	} else {	938	} else {
712	$self->disable ("position_change");	939	$self->disable ("position_change");
713	}	940	}
714		941
715	if (delete $state->{size_sensitive}) {	942	if ($again->{size}) {
716	$repeat = 1;
717	$self->enable (size_change => sub { $_[0]->recalculate });	943	$self->enable (size_change => sub { $_[0]->recalculate });
718	} else {	944	} else {
719	$self->disable ("size_change");	945	$self->disable ("size_change");
720	}	946	}
721		947
722	if (delete $state->{rootpmap_sensitive}) {	948	if ($again->{rootpmap}) {
723	$repeat = 1;
724	$self->enable (rootpmap_change => sub { $_[0]->recalculate });	949	$self->enable (rootpmap_change => sub {
		950	delete $_[0]{once_cache}; # this will override once-block values from
		951	$_[0]->recalculate;
		952	});
725	} else {	953	} else {
726	$self->disable ("rootpmap_change");	954	$self->disable ("rootpmap_change");
727	}	955	}
728		956
729	# clear stuff we no longer need	957	# clear stuff we no longer need
730		958
731	%$old = ();	959	%$old = ();
732		960
733	unless ($repeat) {	961	unless (%$again) {
734	delete $self->{state};	962	delete $self->{state};
735	delete $self->{expr};	963	delete $self->{expr};
736	}	964	}
737		965
738	# set background pixmap	966	# set background pixmap
…		…
743	}	971	}
744		972
745	sub on_start {	973	sub on_start {
746	my ($self) = @_;	974	my ($self) = @_;
747		975
748	my $expr = $self->x_resource ("background.expr")	976	my $expr = $self->x_resource ("%.expr")
749	or return;	977	or return;
750		978
		979	$self->has_render
		980	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		981
751	$self->set_expr (parse_expr $expr);	982	$self->set_expr (parse_expr $expr);
752	$self->{border} = $self->x_resource_boolean ("background.border");	983	$self->{border} = $self->x_resource_boolean ("%.border");
		984
		985	$MIN_INTERVAL = $self->x_resource ("%.interval");
753		986
754	()	987	()
755	}	988	}
756		989

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.40 by root, Fri Jun 8 22:19:21 2012 UTC vs. Revision 1.61 by root, Fri Jun 15 19:50:56 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.40 by root, Fri Jun 8 22:19:21 2012 UTC vs.
Revision 1.61 by root, Fri Jun 15 19:50:56 2012 UTC