[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 1.62 by root, Sun Jun 17 21:58:18 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
231	of your screen. The image is set to extend mode.	263	of your screen.
232		264
233	This function makes your expression root sensitive, that means it will be	265	This function makes your expression root sensitive, that means it will be
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, 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. The tiling mode of the first image is used as
		310	the tiling mdoe of the resulting image.
		311
		312	This function is called automatically when an expression returns multiple
		313	images.
		314
		315	=cut
		316
		317	sub merge(@) {
		318	return $_[0] unless $#_;
		319
		320	# rather annoyingly clumsy, but optimisation is for another time
		321
		322	my $x0 = +1e9;
		323	my $y0 = +1e9;
		324	my $x1 = -1e9;
		325	my $y1 = -1e9;
		326
		327	for (@_) {
		328	my ($x, $y, $w, $h) = $_->geometry;
		329
		330	$x0 = $x if $x0 > $x;
		331	$y0 = $y if $y0 > $y;
		332
		333	$x += $w;
		334	$y += $h;
		335
		336	$x1 = $x if $x1 < $x;
		337	$y1 = $y if $y1 < $y;
		338	}
		339
		340	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		341	$base->repeat_mode ($_[0]->repeat_mode);
		342	$base->fill ([0, 0, 0, 0]);
		343
		344	$base->draw ($_)
		345	for @_;
		346
		347	$base
		348	}
350		349
351	=head2 TILING MODES	350	=head2 TILING MODES
352		351
353	The following operators modify the tiling mode of an image, that is, the	352	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.	353	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	383	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	384	image over another image or the background colour while leaving all
386	background pixels outside the image unchanged.	385	background pixels outside the image unchanged.
387		386
388	Example: load an image and display it in the upper left corner. The rest	387	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	388	of the space is left "empty" (transparent or whatever your compositor does
390	in alpha mode, else background colour).	389	in alpha mode, else background colour).
391		390
392	pad load "mybg.png"	391	pad load "mybg.png"
393		392
394	=item extend $img	393	=item extend $img
395		394
396	Extends the image over the whole plane, using the closest pixel in the	395	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	396	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	397	filtering operations and want the pixels outside the image to have the
399	same values as the pixels near the edge.	398	same values as the pixels near the edge.
400		399
401	Example: just for curiosity, how does this pixel extension stuff work?	400	Example: just for curiosity, how does this pixel extension stuff work?
402		401
…		…
428	$img	427	$img
429	}	428	}
430		429
431	=back	430	=back
432		431
433	=head2 PIXEL OPERATORS	432	=head2 VARIABLE VALUES
434		433
435	The following operators modify the image pixels in various ways.	434	The following functions provide variable data such as the terminal window
		435	dimensions. They are not (Perl-) variables, they just return stuff that
		436	varies. Most of them make your expression sensitive to some events, for
		437	example using C<TW> (terminal width) means your expression is evaluated
		438	again when the terminal is resized.
436		439
437	=over 4	440	=over 4
438		441
439	=item clone $img	442	=item TX
440		443
441	Returns an exact copy of the image.	444	=item TY
442		445
443	=cut	446	Return the X and Y coordinates of the terminal window (the terminal
		447	window is the full window by default, and the character area only when in
		448	border-respect mode).
444		449
		450	Using these functions make your expression sensitive to window moves.
		451
		452	These functions are mainly useful to align images to the root window.
		453
		454	Example: load an image and align it so it looks as if anchored to the
		455	background.
		456
		457	move -TX, -TY, load "mybg.png"
		458
		459	=item TW
		460
		461	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		462	terminal window is the full window by default, and the character area only
		463	when in border-respect mode).
		464
		465	Using these functions make your expression sensitive to window resizes.
		466
		467	These functions are mainly useful to scale images, or to clip images to
		468	the window size to conserve memory.
		469
		470	Example: take the screen background, clip it to the window size, blur it a
		471	bit, align it to the window position and use it as background.
		472
		473	clip move -TX, -TY, once { blur 5, root }
		474
		475	=cut
		476
		477	sub TX() { $new->{again}{position} = 1; $x }
		478	sub TY() { $new->{again}{position} = 1; $y }
		479	sub TW() { $new->{again}{size} = 1; $w }
		480	sub TH() { $new->{again}{size} = 1; $h }
		481
		482	=item now
		483
		484	Returns the current time as (fractional) seconds since the epoch.
		485
		486	Using this expression does I<not> make your expression sensitive to time,
		487	but the next two functions do.
		488
		489	=item again $seconds
		490
		491	When this function is used the expression will be reevaluated again in
		492	C<$seconds> seconds.
		493
		494	Example: load some image and rotate it according to the time of day (as if it were
		495	the hour pointer of a clock). Update this image every minute.
		496
		497	again 60; rotate 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
		498
		499	=item counter $seconds
		500
		501	Like C<again>, but also returns an increasing counter value, starting at
		502	0, which might be useful for some simple animation effects.
		503
		504	=cut
		505
		506	sub now() { urxvt::NOW }
		507
		508	sub again($) {
		509	$new->{again}{time} = $_[0];
		510	}
		511
445	sub clone($) {	512	sub counter($) {
446	$_[0]->clone	513	$new->{again}{time} = $_[0];
		514	$self->{counter} + 0
447	}	515	}
		516
		517	=back
		518
		519	=head2 SHAPE CHANGING OPERATORS
		520
		521	The following operators modify the shape, size or position of the image.
		522
		523	=over 4
448		524
449	=item clip $img	525	=item clip $img
450		526
451	=item clip $width, $height, $img	527	=item clip $width, $height, $img
452		528
…		…
476	$img->sub_rect ($_[0], $_[1], $w, $h)	552	$img->sub_rect ($_[0], $_[1], $w, $h)
477	}	553	}
478		554
479	=item scale $img	555	=item scale $img
480		556
481	=item scale $size_percent, $img	557	=item scale $size_factor, $img
482		558
483	=item scale $width_percent, $height_percent, $img	559	=item scale $width_factor, $height_factor, $img
484		560
485	Scales the image by the given percentages in horizontal	561	Scales the image by the given factors in horizontal
486	(C<$width_percent>) and vertical (C<$height_percent>) direction.	562	(C<$width>) and vertical (C<$height>) direction.
487		563
488	If only one percentage is give, it is used for both directions.	564	If only one factor is give, it is used for both directions.
489		565
490	If no percentages are given, scales the image to the window size without	566	If no factors are given, scales the image to the window size without
491	keeping aspect.	567	keeping aspect.
492		568
493	=item resize $width, $height, $img	569	=item resize $width, $height, $img
494		570
495	Resizes the image to exactly C<$width> times C<$height> pixels.	571	Resizes the image to exactly C<$width> times C<$height> pixels.
496		572
497	=cut	573	=item fit $img
498		574
499	#TODO: maximise, maximise_fill?	575	=item fit $width, $height, $img
		576
		577	Fits the image into the given C<$width> and C<$height> without changing
		578	aspect, or the terminal size. That means it will be shrunk or grown until
		579	the whole image fits into the given area, possibly leaving borders.
		580
		581	=item cover $img
		582
		583	=item cover $width, $height, $img
		584
		585	Similar to C<fit>, but shrinks or grows until all of the area is covered
		586	by the image, so instead of potentially leaving borders, it will cut off
		587	image data that doesn't fit.
		588
		589	=cut
500		590
501	sub scale($;$;$) {	591	sub scale($;$;$) {
502	my $img = pop;	592	my $img = pop;
503		593
504	@_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01)	594	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
505	: @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01)	595	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
506	: $img->scale (TW, TH)	596	: $img->scale (TW, TH)
507	}	597	}
508		598
509	sub resize($$$) {	599	sub resize($$$) {
510	my $img = pop;	600	my $img = pop;
511	$img->scale ($_[0], $_[1])	601	$img->scale ($_[0], $_[1])
		602	}
		603
		604	sub fit($;$$) {
		605	my $img = pop;
		606	my $w = ($_[0] \|\| TW) / $img->w;
		607	my $h = ($_[1] \|\| TH) / $img->h;
		608	scale +(min $w, $h), $img
		609	}
		610
		611	sub cover($;$$) {
		612	my $img = pop;
		613	my $w = ($_[0] \|\| TW) / $img->w;
		614	my $h = ($_[1] \|\| TH) / $img->h;
		615	scale +(max $w, $h), $img
512	}	616	}
513		617
514	=item move $dx, $dy, $img	618	=item move $dx, $dy, $img
515		619
516	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in	620	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
517	the vertical.	621	the vertical.
518		622
519	Example: move the image right by 20 pixels and down by 30.	623	Example: move the image right by 20 pixels and down by 30.
520		624
521	move 20, 30, ...	625	move 20, 30, ...
		626
		627	=item align $xalign, $yalign, $img
		628
		629	Aligns the image according to a factor - C<0> means the image is moved to
		630	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		631	exactly centered and C<1> means it touches the right or bottom edge.
		632
		633	Example: remove any visible border around an image, center it vertically but move
		634	it to the right hand side.
		635
		636	align 1, 0.5, pad $img
		637
		638	=item center $img
		639
		640	=item center $width, $height, $img
		641
		642	Centers the image, i.e. the center of the image is moved to the center of
		643	the terminal window (or the box specified by C<$width> and C<$height> if
		644	given).
		645
		646	Example: load an image and center it.
		647
		648	center pad load "mybg.png"
522		649
523	=item rootalign $img	650	=item rootalign $img
524		651
525	Moves the image so that it appears glued to the screen as opposed to the	652	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	653	window. This gives the illusion of a larger area behind the window. It is
…		…
532	rootalign mirror load "mybg.png"	659	rootalign mirror load "mybg.png"
533		660
534	Example: take the screen background and align it, giving the illusion of	661	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.	662	transparency as long as the window isn't in front of other windows.
536		663
537	rootalign root	664	rootalign root
538		665
539	=cut	666	=cut
540		667
541	sub move($$;$) {	668	sub move($$;$) {
542	my $img = pop->clone;	669	my $img = pop->clone;
543	$img->move ($_[0], $_[1]);	670	$img->move ($_[0], $_[1]);
544	$img	671	$img
545	}	672	}
546		673
		674	sub align($;$$) {
		675	my $img = pop;
		676
		677	move $_[0] * (TW - $img->w),
		678	$_[1] * (TH - $img->h),
		679	$img
		680	}
		681
		682	sub center($;$$) {
		683	my $img = pop;
		684	my $w = $_[0] \|\| TW;
		685	my $h = $_[1] \|\| TH;
		686
		687	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		688	}
		689
547	sub rootalign($) {	690	sub rootalign($) {
548	move -TX, -TY, $_[0]	691	move -TX, -TY, $_[0]
549	}	692	}
550		693
		694	=item rotate $center_x, $center_y, $degrees
		695
		696	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
		697	pointer at C<$center_x> and C<$center_y> (specified as factor of image
		698	width/height).
		699
		700	#TODO# new width, height, maybe more operators?
		701
		702	Example: rotate the image by 90 degrees
		703
		704	=cut
		705
		706	sub rotate($$$$) {
		707	my $img = pop;
		708	$img->rotate (
		709	$_[0] * ($img->w + $img->x),
		710	$_[1] * ($img->h + $img->y),
		711	$_[2] * (3.14159265 / 180),
		712	)
		713	}
		714
		715	=back
		716
		717	=head2 COLOUR MODIFICATIONS
		718
		719	The following operators change the pixels of the image.
		720
		721	=over 4
		722
551	=item contrast $factor, $img	723	=item contrast $factor, $img
552		724
553	=item contrast $r, $g, $b, $img	725	=item contrast $r, $g, $b, $img
554		726
555	=item contrast $r, $g, $b, $a, $img	727	=item contrast $r, $g, $b, $a, $img
556		728
557	Adjusts the I<contrast> of an image.	729	Adjusts the I<contrast> of an image.
558		730
559	#TODO#	731	The first form applies a single C<$factor> to red, green and blue, the
		732	second form applies separate factors to each colour channel, and the last
		733	form includes the alpha channel.
560		734
		735	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		736	contrast.
		737
		738	Due to limitations in the underlying XRender extension, lowering contrast
		739	also reduces brightness, while increasing contrast currently also
		740	increases brightness.
		741
561	=item brightness $factor, $img	742	=item brightness $bias, $img
562		743
563	=item brightness $r, $g, $b, $img	744	=item brightness $r, $g, $b, $img
564		745
565	=item brightness $r, $g, $b, $a, $img	746	=item brightness $r, $g, $b, $a, $img
566		747
567	Adjusts the brightness of an image.	748	Adjusts the brightness of an image.
568		749
		750	The first form applies a single C<$bias> to red, green and blue, the
		751	second form applies separate biases to each colour channel, and the last
		752	form includes the alpha channel.
		753
		754	Values less than 0 reduce brightness, while values larger than 0 increase
		755	it. Useful range is from -1 to 1 - the former results in a black, the
		756	latter in a white picture.
		757
		758	Due to idiosyncrasies in the underlying XRender extension, biases less
		759	than zero can be I<very> slow.
		760
569	=cut	761	=cut
570		762
571	sub contrast($$;$$;$) {	763	sub contrast($$;$$;$) {
572	my $img = pop;	764	my $img = pop;
573	my ($r, $g, $b, $a) = @_;	765	my ($r, $g, $b, $a) = @_;
574		766
575	($g, $b) = ($r, $r) if @_ < 4;	767	($g, $b) = ($r, $r) if @_ < 3;
576	$a = 1 if @_ < 5;	768	$a = 1 if @_ < 4;
577		769
578	$img = $img->clone;	770	$img = $img->clone;
579	$img->contrast ($r, $g, $b, $a);	771	$img->contrast ($r, $g, $b, $a);
580	$img	772	$img
581	}	773	}
582		774
583	sub brightness($$;$$;$) {	775	sub brightness($$;$$;$) {
584	my $img = pop;	776	my $img = pop;
585	my ($r, $g, $b, $a) = @_;	777	my ($r, $g, $b, $a) = @_;
586		778
587	($g, $b) = ($r, $r) if @_ < 4;	779	($g, $b) = ($r, $r) if @_ < 3;
588	$a = 1 if @_ < 5;	780	$a = 1 if @_ < 4;
589		781
590	$img = $img->clone;	782	$img = $img->clone;
591	$img->brightness ($r, $g, $b, $a);	783	$img->brightness ($r, $g, $b, $a);
592	$img	784	$img
593	}	785	}
…		…
609	sub blur($$;$) {	801	sub blur($$;$) {
610	my $img = pop;	802	my $img = pop;
611	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	803	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
612	}	804	}
613		805
614	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees	806	=back
615		807
616	Rotates the image by C<$degrees> degrees, counter-clockwise, around the	808	=head2 OTHER STUFF
617	pointer at C<$center_x> and C<$center_y> (specified as percentage of image
618	width/height), generating a new image with width C<$new_width> and height
619	C<$new_height>.
620		809
621	#TODO# new width, height, maybe more operators?	810	Anything that didn't fit any of the other categories, even after applying
		811	force and closing our eyes.
622		812
623	Example: rotate the image by 90 degrees	813	=over 4
624		814
625	=cut	815	=item once { ... }
626		816
627	sub rotate($$$$$$) {	817	This function takes a code block as argument, that is, one or more
628	my $img = pop;	818	statements enclosed by braces.
629	$img->rotate (	819
630	$_[0],	820	The trick is that this code block is only evaluated once - future calls
631	$_[1],	821	will simply return the original image (yes, it should only be used with
632	$_[2] * $img->w * .01,	822	images).
633	$_[3] * $img->h * .01,	823
634	$_[4] * (3.14159265 / 180),	824	This can be extremely useful to avoid redoign the same slow operations
		825	again and again- for example, if your background expression takes the root
		826	background, blurs it and then root-aligns it it would have to blur the
		827	root background on every window move or resize.
		828
		829	Putting the blur into a C<once> block will make sure the blur is only done
		830	once:
		831
		832	rootlign once { blur 10, root }
		833
		834	This leaves the question of how to force reevaluation of the block, in
		835	case the root background changes: Right now, all once blocks forget that
		836	they ahve been executed before each time the root background changes (if
		837	the expression is sensitive to that) or when C<once_again> is called.
		838
		839	=item once_again
		840
		841	Resets all C<once> block as if they had never been called, i.e. on the
		842	next call they will be reevaluated again.
		843
		844	=cut
		845
		846	sub once(&) {
		847	my $once = $self->{once_cache}{$_[0]+0} \|\|= do {
		848	local $new->{again};
		849	my @res = $_[0]();
		850	[$new->{again}, \@res]
635	)	851	};
		852
		853	$new->{again} = {
		854	%{ $new->{again} },
		855	%{ $once->[0] }
		856	};
		857
		858	# in scalar context we always return the first original result, which
		859	# is not quite how perl works.
		860	wantarray
		861	? @{ $once->[1] }
		862	: $once->[1][0]
		863	}
		864
		865	sub once_again() {
		866	delete $self->{once_cache};
636	}	867	}
637		868
638	=back	869	=back
639		870
640	=cut	871	=cut
…		…
681	($x, $y, $w, $h) =	912	($x, $y, $w, $h) =
682	$self->background_geometry ($self->{border});	913	$self->background_geometry ($self->{border});
683		914
684	# evaluate user expression	915	# evaluate user expression
685		916
686	my $img = eval { $self->{expr}->() };	917	my $img = eval { urxvt::bgdsl::merge $self->{expr}->() };
687	warn $@ if $@;#d#	918	die $@ if $@;
688	die if !UNIVERSAL::isa $img, "urxvt::img";	919	die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";
689		920
690	$state->{size_sensitive} = 1	921	# if the expression is sensitive to external events, prepare reevaluation then
		922
		923	my $again = delete $state->{again};
		924
		925	$again->{size} = 1
691	if $img->repeat_mode != urxvt::RepeatNormal;	926	if $img->repeat_mode != urxvt::RepeatNormal;
692		927
693	# if the expression is sensitive to external events, prepare reevaluation then
694
695	my $repeat;
696
697	if (my $again = $state->{again}) {	928	if (my $again = $again->{time}) {
698	$repeat = 1;
699	my $self = $self;	929	my $self = $self;
700	$state->{timer} = $again == $old->{again}	930	$state->{timer} = $again == $old->{again}
701	? $old->{timer}	931	? $old->{timer}
702	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {	932	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
703	++$self->{counter};	933	++$self->{counter};
704	$self->recalculate	934	$self->recalculate
705	});	935	});
706	}	936	}
707		937
708	if (delete $state->{position_sensitive}) {	938	if ($again->{position}) {
709	$repeat = 1;
710	$self->enable (position_change => sub { $_[0]->recalculate });	939	$self->enable (position_change => sub { $_[0]->recalculate });
711	} else {	940	} else {
712	$self->disable ("position_change");	941	$self->disable ("position_change");
713	}	942	}
714		943
715	if (delete $state->{size_sensitive}) {	944	if ($again->{size}) {
716	$repeat = 1;
717	$self->enable (size_change => sub { $_[0]->recalculate });	945	$self->enable (size_change => sub { $_[0]->recalculate });
718	} else {	946	} else {
719	$self->disable ("size_change");	947	$self->disable ("size_change");
720	}	948	}
721		949
722	if (delete $state->{rootpmap_sensitive}) {	950	if ($again->{rootpmap}) {
723	$repeat = 1;
724	$self->enable (rootpmap_change => sub { $_[0]->recalculate });	951	$self->enable (rootpmap_change => sub {
		952	delete $_[0]{once_cache}; # this will override once-block values from
		953	$_[0]->recalculate;
		954	});
725	} else {	955	} else {
726	$self->disable ("rootpmap_change");	956	$self->disable ("rootpmap_change");
727	}	957	}
728		958
729	# clear stuff we no longer need	959	# clear stuff we no longer need
730		960
731	%$old = ();	961	%$old = ();
732		962
733	unless ($repeat) {	963	unless (%$again) {
734	delete $self->{state};	964	delete $self->{state};
735	delete $self->{expr};	965	delete $self->{expr};
736	}	966	}
737		967
738	# set background pixmap	968	# set background pixmap
…		…
743	}	973	}
744		974
745	sub on_start {	975	sub on_start {
746	my ($self) = @_;	976	my ($self) = @_;
747		977
748	my $expr = $self->x_resource ("background.expr")	978	my $expr = $self->x_resource ("%.expr")
749	or return;	979	or return;
750		980
		981	$self->has_render
		982	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		983
751	$self->set_expr (parse_expr $expr);	984	$self->set_expr (parse_expr $expr);
752	$self->{border} = $self->x_resource_boolean ("background.border");	985	$self->{border} = $self->x_resource_boolean ("%.border");
		986
		987	$MIN_INTERVAL = $self->x_resource ("%.interval");
753		988
754	()	989	()
755	}	990	}
756		991

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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 1.62 by root, Sun Jun 17 21:58:18 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 1.62 by root, Sun Jun 17 21:58:18 2012 UTC