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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.37 by root, Fri Jun 8 20:35:43 2012 UTC vs.
Revision 1.63 by root, Tue Jun 19 18:17:56 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
80	Basically, you always start with a function that "generates" an image	82	Basically, you always start with a function that "generates" an image
…		…
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	TODO	120	Other effects than scaling are also readily available, for example, you can
		121	tile the image to fill the whole window, instead of resizing it:
118		122
		123	tile load "$HOME/mypic.png"
		124
		125	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator
		126	is kind of superfluous.
		127
		128	Another common effect is to mirror the image, so that the same edges touch:
		129
		130	mirror load "$HOME/mypic.png"
		131
		132	This is also a typical background expression:
		133
		134	rootalign root
		135
		136	It first takes a snapshot of the screen background image, and then
		137	moves it to the upper left corner of the screen - the result is
		138	pseudo-transparency, as the image seems to be static while the window is
		139	moved around.
		140
119	=head3 CYCLES AND CACHING	141	=head2 CYCLES AND CACHING
120		142
121	TODO	143	=head3 C<load> et al.
122		144
		145	As has been mentioned before, the expression might be evaluated multiple
123	Each time the expression is reevaluated, a new cycle is said to have begun. Many operators	146	times. Each time the expression is reevaluated, a new cycle is said to
124	cache their results till the next cycle. For example	147	have begun. Many operators cache their results till the next cycle.
125		148
		149	For example, the C<load> operator keeps a copy of the image. If it is
		150	asked to load the same image on the next cycle it will not load it again,
		151	but return the cached copy.
		152
		153	This only works for one cycle though, so as long as you load the same
		154	image every time, it will always be cached, but when you load a different
		155	image, it will forget about the first one.
		156
		157	This allows you to either speed things up by keeping multiple images in
		158	memory, or conserve memory by loading images more often.
		159
		160	For example, you can keep two images in memory and use a random one like
		161	this:
		162
		163	my $img1 = load "img1.png";
		164	my $img2 = load "img2.png";
		165	(0.5 > rand) ? $img1 : $img2
		166
		167	Since both images are "loaded" every time the expression is evaluated,
		168	they are always kept in memory. Contrast this version:
		169
		170	my $path1 = "img1.png";
		171	my $path2 = "img2.png";
		172	load ((0.5 > rand) ? $path1 : $path2)
		173
		174	Here, a path is selected randomly, and load is only called for one image,
		175	so keeps only one image in memory. If, on the next evaluation, luck
		176	decides to use the other path, then it will have to load that image again.
		177
		178	=head3 C<once { ... }>
		179
		180	Another way to cache expensive operations is to use C<once { ... }>. The
		181	C<once> operator takes a block of multiple statements enclosed by C<{}>
		182	and evaluates it only.. once, returning any images the last statement
		183	returned. Further calls simply produce the values from the cache.
		184
		185	This is most useful for expensive operations, such as C<blur>:
		186
		187	rootalign once { blur 20, root }
		188
		189	This makes a blurred copy of the root background once, and on subsequent
		190	calls, just root-aligns it. Since C<blur> is usually quite slow and
		191	C<rootalign> is quite fast, this trades extra memory (For the cached
		192	blurred pixmap) with speed (blur only needs to be redone when root
		193	changes).
		194
126	=head2 REFERENCE	195	=head1 REFERENCE
127		196
128	=head3 COMMAND LINE SWITCHES	197	=head2 COMMAND LINE SWITCHES
129		198
130	=over 4	199	=over 4
131		200
132	=item --background-expr perl-expression	201	=item --background-expr perl-expression
133		202
…		…
139	overwriting borders and any other areas, such as the scrollbar.	208	overwriting borders and any other areas, such as the scrollbar.
140		209
141	Specifying this flag changes the behaviour, so that the image only	210	Specifying this flag changes the behaviour, so that the image only
142	replaces the background of the character area.	211	replaces the background of the character area.
143		212
		213	=item --background-interval seconds
		214
		215	Since some operations in the underlying XRender extension can effectively
		216	freeze your X-server for prolonged time, this extension enforces a minimum
		217	time between updates, which is normally about 0.1 seconds.
		218
		219	If you want to do updates more often, you can decrease this safety
		220	interval with this switch.
		221
144	=back	222	=back
145		223
146	=cut	224	=cut
147		225
148	our $EXPR;#d#	226	our %_IMG_CACHE;
149	#$EXPR = 'move W * 0.1, -H * 0.1, resize W * 0.5, H * 0.5, repeat_none load "opensource.png"';
150	$EXPR = 'move -TX, -TY, load "argb.png"';
151	#$EXPR = '
152	# rotate W, H, 50, 50, counter 1/59.95, repeat_mirror,
153	# clip X, Y, W, H, repeat_mirror,
154	# load "/root/pix/das_fette_schwein.jpg"
155	#';
156	#$EXPR = 'solid "red"';
157	#$EXPR = 'blur root, 10, 10'
158	#$EXPR = 'blur move (root, -x, -y), 5, 5'
159	#resize load "/root/pix/das_fette_schwein.jpg", w, h
160
161	our $HOME;	227	our $HOME;
162	our ($self, $old, $new);	228	our ($self, $frame);
163	our ($x, $y, $w, $h);	229	our ($x, $y, $w, $h);
164		230
165	# enforce at least this interval between updates	231	# enforce at least this interval between updates
166	our $MIN_INTERVAL = 1/100;	232	our $MIN_INTERVAL = 6/59.951;
167		233
168	{	234	{
169	package urxvt::bgdsl; # background language	235	package urxvt::bgdsl; # background language
		236
		237	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
		238	sub FR_CACHE () { 1 } # cached values
		239	sub FR_AGAIN () { 2 } # what this expr is sensitive to
		240	sub FR_STATE () { 3 } # watchers etc.
		241
		242	use List::Util qw(min max sum shuffle);
170		243
171	=head2 PROVIDERS/GENERATORS	244	=head2 PROVIDERS/GENERATORS
172		245
173	These functions provide an image, by loading it from disk, grabbing it	246	These functions provide an image, by loading it from disk, grabbing it
174	from the root screen or by simply generating it. They are used as starting	247	from the root screen or by simply generating it. They are used as starting
…		…
179	=item load $path	252	=item load $path
180		253
181	Loads the image at the given C<$path>. The image is set to plane tiling	254	Loads the image at the given C<$path>. The image is set to plane tiling
182	mode.	255	mode.
183		256
184	Loaded images will be cached for one cycle.	257	Loaded images will be cached for one cycle, and shared between temrinals
		258	running in the same process (e.g. in C<urxvtd>).
		259
		260	#=item load_uc $path
		261	#
		262	#Load uncached - same as load, but does not cache the image. This function
		263	#is most useufl if you want to optimise a background expression in some
		264	#way.
185		265
186	=cut	266	=cut
187		267
188	sub load($) {	268	sub load($) {
189	my ($path) = @_;	269	my ($path) = @_;
190		270
191	$new->{load}{$path} = $old->{load}{$path} \|\| $self->new_img_from_file ($path);	271	$_IMG_CACHE{$path} \|\| do {
		272	my $img = $self->new_img_from_file ($path);
		273	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		274	$img
		275	}
192	}	276	}
193		277
194	=item root	278	=item root
195		279
196	Returns the root window pixmap, that is, hopefully, the background image	280	Returns the root window pixmap, that is, hopefully, the background image
197	of your screen. The image is set to extend mode.	281	of your screen.
198		282
199	This function makes your expression root sensitive, that means it will be	283	This function makes your expression root sensitive, that means it will be
200	reevaluated when the bg image changes.	284	reevaluated when the bg image changes.
201		285
202	=cut	286	=cut
203		287
204	sub root() {	288	sub root() {
205	$new->{rootpmap_sensitive} = 1;	289	$frame->[FR_AGAIN]{rootpmap} = 1;
206	die "root op not supported, exg, we need you";	290	$self->new_img_from_root
207	}	291	}
208		292
209	=item solid $colour	293	=item solid $colour
210		294
211	=item solid $width, $height, $colour	295	=item solid $width, $height, $colour
212		296
213	Creates a new image and completely fills it with the given colour. The	297	Creates a new image and completely fills it with the given colour. The
214	image is set to tiling mode.	298	image is set to tiling mode.
215		299
216	If <$width> and C<$height> are omitted, it creates a 1x1 image, which is	300	If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
217	useful for solid backgrounds or for use in filtering effects.	301	useful for solid backgrounds or for use in filtering effects.
218		302
219	=cut	303	=cut
220		304
221	sub solid($$;$) {	305	sub solid($;$$) {
222	my $colour = pop;	306	my $colour = pop;
223		307
224	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	308	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
225	$img->fill ($colour);	309	$img->fill ($colour);
226	$img	310	$img
227	}	311	}
228		312
229	=back	313	=item clone $img
230		314
231	=head2 VARIABLES	315	Returns an exact copy of the image. This is useful if you want to have
		316	multiple copies of the same image to apply different effects to.
232		317
233	The following functions provide variable data such as the terminal
234	window dimensions. Most of them make your expression sensitive to some
235	events, for example using C<TW> (terminal width) means your expression is
236	evaluated again when the terminal is resized.
237
238	=over 4
239
240	=item TX
241
242	=item TY
243
244	Return the X and Y coordinates of the terminal window (the terminal
245	window is the full window by default, and the character area only when in
246	border-respect mode).
247
248	Using these functions make your expression sensitive to window moves.
249
250	These functions are mainly useful to align images to the root window.
251
252	Example: load an image and align it so it looks as if anchored to the
253	background.
254
255	move -TX, -TY, load "mybg.png"
256
257	=item TW
258
259	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
260	terminal window is the full window by default, and the character area only
261	when in border-respect mode).
262
263	Using these functions make your expression sensitive to window resizes.
264
265	These functions are mainly useful to scale images, or to clip images to
266	the window size to conserve memory.
267
268	Example: take the screen background, clip it to the window size, blur it a
269	bit, align it to the window position and use it as background.
270
271	clip move -TX, -TY, blur 5, root
272
273	=cut	318	=cut
274		319
275	sub TX() { $new->{position_sensitive} = 1; $x }
276	sub TY() { $new->{position_sensitive} = 1; $y }
277	sub TW() { $new->{size_sensitive} = 1; $w }
278	sub TH() { $new->{size_sensitive} = 1; $h }
279
280	=item now
281
282	Returns the current time as (fractional) seconds since the epoch.
283
284	Using this expression does I<not> make your expression sensitive to time,
285	but the next two functions do.
286
287	=item again $seconds
288
289	When this function is used the expression will be reevaluated again in
290	C<$seconds> seconds.
291
292	Example: load some image and rotate it according to the time of day (as if it were
293	the hour pointer of a clock). Update this image every minute.
294
295	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
296
297	=item counter $seconds
298
299	Like C<again>, but also returns an increasing counter value, starting at
300	0, which might be useful for some simple animation effects.
301
302	=cut
303
304	sub now() { urxvt::NOW }
305
306	sub again($) {
307	$new->{again} = $_[0];
308	}
309
310	sub counter($) {	320	sub clone($) {
311	$new->{again} = $_[0];	321	$_[0]->clone
312	$self->{counter} + 0
313	}	322	}
314		323
315	=back	324	=item merge $img ...
		325
		326	Takes any number of images and merges them together, creating a single
		327	image containing them all. The tiling mode of the first image is used as
		328	the tiling mdoe of the resulting image.
		329
		330	This function is called automatically when an expression returns multiple
		331	images.
		332
		333	=cut
		334
		335	sub merge(@) {
		336	return $_[0] unless $#_;
		337
		338	# rather annoyingly clumsy, but optimisation is for another time
		339
		340	my $x0 = +1e9;
		341	my $y0 = +1e9;
		342	my $x1 = -1e9;
		343	my $y1 = -1e9;
		344
		345	for (@_) {
		346	my ($x, $y, $w, $h) = $_->geometry;
		347
		348	$x0 = $x if $x0 > $x;
		349	$y0 = $y if $y0 > $y;
		350
		351	$x += $w;
		352	$y += $h;
		353
		354	$x1 = $x if $x1 < $x;
		355	$y1 = $y if $y1 < $y;
		356	}
		357
		358	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		359	$base->repeat_mode ($_[0]->repeat_mode);
		360	$base->fill ([0, 0, 0, 0]);
		361
		362	$base->draw ($_)
		363	for @_;
		364
		365	$base
		366	}
316		367
317	=head2 TILING MODES	368	=head2 TILING MODES
318		369
319	The following operators modify the tiling mode of an image, that is, the	370	The following operators modify the tiling mode of an image, that is, the
320	way that pixels outside the image area are painted when the image is used.	371	way that pixels outside the image area are painted when the image is used.
…		…
350	become transparent. This mode is most useful when you want to place an	401	become transparent. This mode is most useful when you want to place an
351	image over another image or the background colour while leaving all	402	image over another image or the background colour while leaving all
352	background pixels outside the image unchanged.	403	background pixels outside the image unchanged.
353		404
354	Example: load an image and display it in the upper left corner. The rest	405	Example: load an image and display it in the upper left corner. The rest
355	of the space is left "empty" (transparent or wahtever your compisotr does	406	of the space is left "empty" (transparent or whatever your compositor does
356	in alpha mode, else background colour).	407	in alpha mode, else background colour).
357		408
358	pad load "mybg.png"	409	pad load "mybg.png"
359		410
360	=item extend $img	411	=item extend $img
361		412
362	Extends the image over the whole plane, using the closest pixel in the	413	Extends the image over the whole plane, using the closest pixel in the
363	area outside the image. This mode is mostly useful when you more complex	414	area outside the image. This mode is mostly useful when you use more complex
364	filtering operations and want the pixels outside the image to have the	415	filtering operations and want the pixels outside the image to have the
365	same values as the pixels near the edge.	416	same values as the pixels near the edge.
366		417
367	Example: just for curiosity, how does this pixel extension stuff work?	418	Example: just for curiosity, how does this pixel extension stuff work?
368		419
…		…
394	$img	445	$img
395	}	446	}
396		447
397	=back	448	=back
398		449
399	=head2 PIXEL OPERATORS	450	=head2 VARIABLE VALUES
400		451
401	The following operators modify the image pixels in various ways.	452	The following functions provide variable data such as the terminal window
		453	dimensions. They are not (Perl-) variables, they just return stuff that
		454	varies. Most of them make your expression sensitive to some events, for
		455	example using C<TW> (terminal width) means your expression is evaluated
		456	again when the terminal is resized.
402		457
403	=over 4	458	=over 4
404		459
405	=item clone $img	460	=item TX
406		461
407	Returns an exact copy of the image.	462	=item TY
408		463
409	=cut	464	Return the X and Y coordinates of the terminal window (the terminal
		465	window is the full window by default, and the character area only when in
		466	border-respect mode).
410		467
		468	Using these functions make your expression sensitive to window moves.
		469
		470	These functions are mainly useful to align images to the root window.
		471
		472	Example: load an image and align it so it looks as if anchored to the
		473	background.
		474
		475	move -TX, -TY, load "mybg.png"
		476
		477	=item TW
		478
		479	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		480	terminal window is the full window by default, and the character area only
		481	when in border-respect mode).
		482
		483	Using these functions make your expression sensitive to window resizes.
		484
		485	These functions are mainly useful to scale images, or to clip images to
		486	the window size to conserve memory.
		487
		488	Example: take the screen background, clip it to the window size, blur it a
		489	bit, align it to the window position and use it as background.
		490
		491	clip move -TX, -TY, once { blur 5, root }
		492
		493	=cut
		494
		495	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
		496	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
		497	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
		498	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
		499
		500	=item now
		501
		502	Returns the current time as (fractional) seconds since the epoch.
		503
		504	Using this expression does I<not> make your expression sensitive to time,
		505	but the next two functions do.
		506
		507	=item again $seconds
		508
		509	When this function is used the expression will be reevaluated again in
		510	C<$seconds> seconds.
		511
		512	Example: load some image and rotate it according to the time of day (as if it were
		513	the hour pointer of a clock). Update this image every minute.
		514
		515	again 60; rotate 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
		516
		517	=item counter $seconds
		518
		519	Like C<again>, but also returns an increasing counter value, starting at
		520	0, which might be useful for some simple animation effects.
		521
		522	=cut
		523
		524	sub now() { urxvt::NOW }
		525
		526	sub again($) {
		527	$frame->[FR_AGAIN]{time} = $_[0];
		528	}
		529
411	sub clone($) {	530	sub counter($) {
412	$_[0]->clone	531	$frame->[FR_AGAIN]{time} = $_[0];
		532	$frame->[FR_STATE]{counter} + 0
413	}	533	}
		534
		535	=back
		536
		537	=head2 SHAPE CHANGING OPERATORS
		538
		539	The following operators modify the shape, size or position of the image.
		540
		541	=over 4
414		542
415	=item clip $img	543	=item clip $img
416		544
417	=item clip $width, $height, $img	545	=item clip $width, $height, $img
418		546
…		…
442	$img->sub_rect ($_[0], $_[1], $w, $h)	570	$img->sub_rect ($_[0], $_[1], $w, $h)
443	}	571	}
444		572
445	=item scale $img	573	=item scale $img
446		574
447	=item scale $size_percent, $img	575	=item scale $size_factor, $img
448		576
449	=item scale $width_percent, $height_percent, $img	577	=item scale $width_factor, $height_factor, $img
450		578
451	Scales the image by the given percentages in horizontal	579	Scales the image by the given factors in horizontal
452	(C<$width_percent>) and vertical (C<$height_percent>) direction.	580	(C<$width>) and vertical (C<$height>) direction.
453		581
454	If only one percentage is give, it is used for both directions.	582	If only one factor is give, it is used for both directions.
455		583
456	If no percentages are given, scales the image to the window size without	584	If no factors are given, scales the image to the window size without
457	keeping aspect.	585	keeping aspect.
458		586
459	=item resize $width, $height, $img	587	=item resize $width, $height, $img
460		588
461	Resizes the image to exactly C<$width> times C<$height> pixels.	589	Resizes the image to exactly C<$width> times C<$height> pixels.
462		590
463	=cut	591	=item fit $img
464		592
465	#TODO: maximise, maximise_fill?	593	=item fit $width, $height, $img
		594
		595	Fits the image into the given C<$width> and C<$height> without changing
		596	aspect, or the terminal size. That means it will be shrunk or grown until
		597	the whole image fits into the given area, possibly leaving borders.
		598
		599	=item cover $img
		600
		601	=item cover $width, $height, $img
		602
		603	Similar to C<fit>, but shrinks or grows until all of the area is covered
		604	by the image, so instead of potentially leaving borders, it will cut off
		605	image data that doesn't fit.
		606
		607	=cut
466		608
467	sub scale($;$;$) {	609	sub scale($;$;$) {
468	my $img = pop;	610	my $img = pop;
469		611
470	@_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01)	612	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
471	: @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01)	613	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
472	: $img->scale (TW, TH)	614	: $img->scale (TW, TH)
473	}	615	}
474		616
475	sub resize($$$) {	617	sub resize($$$) {
476	my $img = pop;	618	my $img = pop;
477	$img->scale ($_[0], $_[1])	619	$img->scale ($_[0], $_[1])
478	}	620	}
479		621
		622	sub fit($;$$) {
		623	my $img = pop;
		624	my $w = ($_[0] \|\| TW) / $img->w;
		625	my $h = ($_[1] \|\| TH) / $img->h;
		626	scale +(min $w, $h), $img
		627	}
		628
		629	sub cover($;$$) {
		630	my $img = pop;
		631	my $w = ($_[0] \|\| TW) / $img->w;
		632	my $h = ($_[1] \|\| TH) / $img->h;
		633	scale +(max $w, $h), $img
		634	}
		635
480	=item move $dx, $dy, $img	636	=item move $dx, $dy, $img
481		637
482	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in	638	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
483	the vertical.	639	the vertical.
484		640
485	Example: move the image right by 20 pixels and down by 30.	641	Example: move the image right by 20 pixels and down by 30.
486		642
487	move 20, 30, ...	643	move 20, 30, ...
		644
		645	=item align $xalign, $yalign, $img
		646
		647	Aligns the image according to a factor - C<0> means the image is moved to
		648	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		649	exactly centered and C<1> means it touches the right or bottom edge.
		650
		651	Example: remove any visible border around an image, center it vertically but move
		652	it to the right hand side.
		653
		654	align 1, 0.5, pad $img
		655
		656	=item center $img
		657
		658	=item center $width, $height, $img
		659
		660	Centers the image, i.e. the center of the image is moved to the center of
		661	the terminal window (or the box specified by C<$width> and C<$height> if
		662	given).
		663
		664	Example: load an image and center it.
		665
		666	center pad load "mybg.png"
488		667
489	=item rootalign $img	668	=item rootalign $img
490		669
491	Moves the image so that it appears glued to the screen as opposed to the	670	Moves the image so that it appears glued to the screen as opposed to the
492	window. This gives the illusion of a larger area behind the window. It is	671	window. This gives the illusion of a larger area behind the window. It is
…		…
498	rootalign mirror load "mybg.png"	677	rootalign mirror load "mybg.png"
499		678
500	Example: take the screen background and align it, giving the illusion of	679	Example: take the screen background and align it, giving the illusion of
501	transparency as long as the window isn't in front of other windows.	680	transparency as long as the window isn't in front of other windows.
502		681
503	rootalign root	682	rootalign root
504		683
505	=cut	684	=cut
506		685
507	sub move($$;$) {	686	sub move($$;$) {
508	my $img = pop->clone;	687	my $img = pop->clone;
509	$img->move ($_[0], $_[1]);	688	$img->move ($_[0], $_[1]);
510	$img	689	$img
511	}	690	}
512		691
		692	sub align($;$$) {
		693	my $img = pop;
		694
		695	move $_[0] * (TW - $img->w),
		696	$_[1] * (TH - $img->h),
		697	$img
		698	}
		699
		700	sub center($;$$) {
		701	my $img = pop;
		702	my $w = $_[0] \|\| TW;
		703	my $h = $_[1] \|\| TH;
		704
		705	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		706	}
		707
513	sub rootalign($) {	708	sub rootalign($) {
514	move -TX, -TY, $_[0]	709	move -TX, -TY, $_[0]
515	}	710	}
516		711
		712	=item rotate $center_x, $center_y, $degrees
		713
		714	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
		715	pointer at C<$center_x> and C<$center_y> (specified as factor of image
		716	width/height).
		717
		718	#TODO# new width, height, maybe more operators?
		719
		720	Example: rotate the image by 90 degrees
		721
		722	=cut
		723
		724	sub rotate($$$$) {
		725	my $img = pop;
		726	$img->rotate (
		727	$_[0] * ($img->w + $img->x),
		728	$_[1] * ($img->h + $img->y),
		729	$_[2] * (3.14159265 / 180),
		730	)
		731	}
		732
		733	=back
		734
		735	=head2 COLOUR MODIFICATIONS
		736
		737	The following operators change the pixels of the image.
		738
		739	=over 4
		740
517	=item contrast $factor, $img	741	=item contrast $factor, $img
518		742
519	=item contrast $r, $g, $b, $img	743	=item contrast $r, $g, $b, $img
520		744
521	=item contrast $r, $g, $b, $a, $img	745	=item contrast $r, $g, $b, $a, $img
522		746
523	Adjusts the I<contrast> of an image.	747	Adjusts the I<contrast> of an image.
524		748
		749	The first form applies a single C<$factor> to red, green and blue, the
		750	second form applies separate factors to each colour channel, and the last
		751	form includes the alpha channel.
		752
		753	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		754	contrast.
		755
		756	Due to limitations in the underlying XRender extension, lowering contrast
		757	also reduces brightness, while increasing contrast currently also
		758	increases brightness.
		759
525	=item brightness $factor, $img	760	=item brightness $bias, $img
526		761
527	=item brightness $r, $g, $b, $img	762	=item brightness $r, $g, $b, $img
528		763
529	=item brightness $r, $g, $b, $a, $img	764	=item brightness $r, $g, $b, $a, $img
		765
		766	Adjusts the brightness of an image.
		767
		768	The first form applies a single C<$bias> to red, green and blue, the
		769	second form applies separate biases to each colour channel, and the last
		770	form includes the alpha channel.
		771
		772	Values less than 0 reduce brightness, while values larger than 0 increase
		773	it. Useful range is from -1 to 1 - the former results in a black, the
		774	latter in a white picture.
		775
		776	Due to idiosyncrasies in the underlying XRender extension, biases less
		777	than zero can be I<very> slow.
530		778
531	=cut	779	=cut
532		780
533	sub contrast($$;$$;$) {	781	sub contrast($$;$$;$) {
534	my $img = pop;	782	my $img = pop;
535	my ($r, $g, $b, $a) = @_;	783	my ($r, $g, $b, $a) = @_;
536		784
537	($g, $b) = ($r, $r) if @_ < 4;	785	($g, $b) = ($r, $r) if @_ < 3;
538	$a = 1 if @_ < 5;	786	$a = 1 if @_ < 4;
539		787
540	$img = $img->clone;	788	$img = $img->clone;
541	$img->contrast ($r, $g, $b, $a);	789	$img->contrast ($r, $g, $b, $a);
542	$img	790	$img
543	}	791	}
544		792
545	sub brightness($$;$$;$) {	793	sub brightness($$;$$;$) {
546	my $img = pop;	794	my $img = pop;
547	my ($r, $g, $b, $a) = @_;	795	my ($r, $g, $b, $a) = @_;
548		796
549	($g, $b) = ($r, $r) if @_ < 4;	797	($g, $b) = ($r, $r) if @_ < 3;
550	$a = 1 if @_ < 5;	798	$a = 1 if @_ < 4;
551		799
552	$img = $img->clone;	800	$img = $img->clone;
553	$img->brightness ($r, $g, $b, $a);	801	$img->brightness ($r, $g, $b, $a);
554	$img	802	$img
555	}	803	}
556		804
		805	=item blur $radius, $img
		806
		807	=item blur $radius_horz, $radius_vert, $img
		808
		809	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
		810	can also be specified separately.
		811
		812	Blurring is often I<very> slow, at least compared or other
		813	operators. Larger blur radii are slower than smaller ones, too, so if you
		814	don't want to freeze your screen for long times, start experimenting with
		815	low values for radius (<5).
		816
		817	=cut
		818
557	sub blur($$;$) {	819	sub blur($$;$) {
558	my $img = pop;	820	my $img = pop;
559	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	821	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
560	}	822	}
561		823
562	sub rotate($$$$$$) {
563	my $img = pop;
564	$img->rotate (
565	$_[0],
566	$_[1],
567	$_[2] * $img->w * .01,
568	$_[3] * $img->h * .01,
569	$_[4] * (3.14159265 / 180),
570	)
571	}
572
573	=back	824	=back
574		825
		826	=head2 OTHER STUFF
		827
		828	Anything that didn't fit any of the other categories, even after applying
		829	force and closing our eyes.
		830
		831	=over 4
		832
		833	=item once { ... }
		834
		835	This function takes a code block as argument, that is, one or more
		836	statements enclosed by braces.
		837
		838	The trick is that this code block is only evaluated once - future calls
		839	will simply return the original image (yes, it should only be used with
		840	images).
		841
		842	This can be extremely useful to avoid redoing the same slow operations
		843	again and again- for example, if your background expression takes the root
		844	background, blurs it and then root-aligns it it would have to blur the
		845	root background on every window move or resize.
		846
		847	In fact, urxvt itself encloses the whole expression in some kind of
		848	C<once> block so it only is reevaluated as required.
		849
		850	Putting the blur into a C<once> block will make sure the blur is only done
		851	once:
		852
		853	rootlign once { blur 10, root }
		854
		855	This leaves the question of how to force reevaluation of the block,
		856	in case the root background changes: If expression inside the block
		857	is sensitive to some event (root background changes, window geometry
		858	changes), then it will be reevaluated automatically as needed.
		859
		860	=item once_again
		861
		862	Resets all C<once> block as if they had never been called, i.e. on the
		863	next call they will be reevaluated again.
		864
		865	=cut
		866
		867	sub once(&) {
		868	my $id = $_[0]+0;
		869
		870	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		871
		872	unless ($frame->[FR_CACHE]) {
		873	$frame->[FR_CACHE] = [ $_[0]() ];
		874
		875	my $self = $self;
		876	my $frame = $frame;
		877	Scalar::Util::weaken $frame;
		878	$self->compile_frame ($frame, sub {
		879	# clear this frame cache, also for all parents
		880	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		881	undef $frame->[FR_CACHE];
		882	}
		883
		884	unless ($self->{term}) {
		885	use Data::Dump;
		886	ddx $frame;
		887	exit;
		888	}
		889
		890	$self->recalculate;
		891	});
		892	};
		893
		894	# in scalar context we always return the first original result, which
		895	# is not quite how perl works.
		896	wantarray
		897	? @{ $frame->[FR_CACHE] }
		898	: $frame->[FR_CACHE][0]
		899	}
		900
		901	sub once_again() {
		902	delete $self->{frame_cache};
		903	}
		904
		905	=back
		906
575	=cut	907	=cut
576		908
577	}	909	}
578		910
579	sub parse_expr {	911	sub parse_expr {
580	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	912	my $expr = eval
		913	"sub {\n"
		914	. "package urxvt::bgdsl;\n"
		915	. "#line 0 'background expression'\n"
		916	. "$_[0]\n"
		917	. "}";
581	die if $@;	918	die if $@;
582	$expr	919	$expr
583	}	920	}
584		921
585	# compiles a parsed expression	922	# compiles a parsed expression
586	sub set_expr {	923	sub set_expr {
587	my ($self, $expr) = @_;	924	my ($self, $expr) = @_;
588		925
		926	$self->{root} = [];
589	$self->{expr} = $expr;	927	$self->{expr} = $expr;
590	$self->recalculate;	928	$self->recalculate;
		929	}
		930
		931	# takes a hash of sensitivity indicators and installs watchers
		932	sub compile_frame {
		933	my ($self, $frame, $cb) = @_;
		934
		935	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		936	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		937
		938	# don't keep stuff alive
		939	Scalar::Util::weaken $state;
		940
		941	if ($again->{nested}) {
		942	$state->{nested} = 1;
		943	} else {
		944	delete $state->{nested};
		945	}
		946
		947	if (my $interval = $again->{time}) {
		948	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		949	if $state->{time}[0] != $interval;
		950
		951	# callback might have changed, although we could just rule that out
		952	$state->{time}[1]->cb (sub {
		953	++$state->{counter};
		954	$cb->();
		955	});
		956	} else {
		957	delete $state->{time};
		958	}
		959
		960	if ($again->{position}) {
		961	$state->{position} = $self->on (position_change => $cb);
		962	} else {
		963	delete $state->{position};
		964	}
		965
		966	if ($again->{size}) {
		967	$state->{size} = $self->on (size_change => $cb);
		968	} else {
		969	delete $state->{size};
		970	}
		971
		972	if ($again->{rootpmap}) {
		973	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		974	} else {
		975	delete $state->{rootpmap};
		976	}
591	}	977	}
592		978
593	# evaluate the current bg expression	979	# evaluate the current bg expression
594	sub recalculate {	980	sub recalculate {
595	my ($arg_self) = @_;	981	my ($arg_self) = @_;
…		…
605		991
606	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	992	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
607		993
608	# set environment to evaluate user expression	994	# set environment to evaluate user expression
609		995
610	local $self = $arg_self;	996	local $self = $arg_self;
611
612	local $HOME = $ENV{HOME};	997	local $HOME = $ENV{HOME};
613	local $old = $self->{state};	998	local $frame = [];
614	local $new = my $state = $self->{state} = {};
615		999
616	($x, $y, $w, $h) =
617	$self->background_geometry ($self->{border});	1000	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
618		1001
619	# evaluate user expression	1002	# evaluate user expression
620		1003
621	my $img = eval { $self->{expr}->() };	1004	my @img = eval { $self->{expr}->() };
622	warn $@ if $@;#d#	1005	die $@ if $@;
		1006	die "background-expr did not return anything.\n" unless @img;
		1007	die "background-expr: expected image(s), got something else.\n"
623	die if !UNIVERSAL::isa $img, "urxvt::img";	1008	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
624		1009
625	$state->{size_sensitive} = 1	1010	my $img = urxvt::bgdsl::merge @img;
		1011
		1012	$frame->[FR_AGAIN]{size} = 1
626	if $img->repeat_mode != urxvt::RepeatNormal;	1013	if $img->repeat_mode != urxvt::RepeatNormal;
627		1014
628	# if the expression is sensitive to external events, prepare reevaluation then	1015	# if the expression is sensitive to external events, prepare reevaluation then
629		1016	$self->compile_frame ($frame, sub { $arg_self->recalculate });
630	my $repeat;
631
632	if (my $again = $state->{again}) {
633	$repeat = 1;
634	my $self = $self;
635	$state->{timer} = $again == $old->{again}
636	? $old->{timer}
637	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
638	++$self->{counter};
639	$self->recalculate
640	});
641	}
642
643	if (delete $state->{position_sensitive}) {
644	$repeat = 1;
645	$self->enable (position_change => sub { $_[0]->recalculate });
646	} else {
647	$self->disable ("position_change");
648	}
649
650	if (delete $state->{size_sensitive}) {
651	$repeat = 1;
652	$self->enable (size_change => sub { $_[0]->recalculate });
653	} else {
654	$self->disable ("size_change");
655	}
656
657	if (delete $state->{rootpmap_sensitive}) {
658	$repeat = 1;
659	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
660	} else {
661	$self->disable ("rootpmap_change");
662	}
663		1017
664	# clear stuff we no longer need	1018	# clear stuff we no longer need
665		1019
666	%$old = ();	1020	# unless (%{ $frame->[FR_STATE] }) {
667
668	unless ($repeat) {
669	delete $self->{state};	1021	# delete $self->{state};
670	delete $self->{expr};	1022	# delete $self->{expr};
671	}	1023	# }
672		1024
673	# set background pixmap	1025	# set background pixmap
674		1026
675	$self->set_background ($img, $self->{border});	1027	$self->set_background ($img, $self->{border});
676	$self->scr_recolour (0);	1028	$self->scr_recolour (0);
…		…
678	}	1030	}
679		1031
680	sub on_start {	1032	sub on_start {
681	my ($self) = @_;	1033	my ($self) = @_;
682		1034
683	my $expr = $self->x_resource ("background.expr")	1035	my $expr = $self->x_resource ("%.expr")
684	or return;	1036	or return;
685		1037
		1038	$self->has_render
		1039	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1040
686	$self->set_expr (parse_expr $expr);	1041	$self->set_expr (parse_expr $expr);
687	$self->{border} = $self->x_resource_boolean ("background.border");	1042	$self->{border} = $self->x_resource_boolean ("%.border");
		1043
		1044	$MIN_INTERVAL = $self->x_resource ("%.interval");
688		1045
689	()	1046	()
690	}	1047	}
691		1048

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.37 by root, Fri Jun 8 20:35:43 2012 UTC vs. Revision 1.63 by root, Tue Jun 19 18:17:56 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.37 by root, Fri Jun 8 20:35:43 2012 UTC vs.
Revision 1.63 by root, Tue Jun 19 18:17:56 2012 UTC