[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 1.62 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
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	As has been mentioned before, the expression might be evaluated multiple
122
123	Each time the expression is reevaluated, a new cycle is said to have begun. Many operators	144	times. Each time the expression is reevaluated, a new cycle is said to
124	cache their results till the next cycle. For example	145	have begun. Many operators cache their results till the next cycle.
125		146
		147	For example, the C<load> operator keeps a copy of the image. If it is
		148	asked to load the same image on the next cycle it will not load it again,
		149	but return the cached copy.
		150
		151	This only works for one cycle though, so as long as you load the same
		152	image every time, it will always be cached, but when you load a different
		153	image, it will forget about the first one.
		154
		155	This allows you to either speed things up by keeping multiple images in
		156	memory, or conserve memory by loading images more often.
		157
		158	For example, you can keep two images in memory and use a random one like
		159	this:
		160
		161	my $img1 = load "img1.png";
		162	my $img2 = load "img2.png";
		163	(0.5 > rand) ? $img1 : $img2
		164
		165	Since both images are "loaded" every time the expression is evaluated,
		166	they are always kept in memory. Contrast this version:
		167
		168	my $path1 = "img1.png";
		169	my $path2 = "img2.png";
		170	load ((0.5 > rand) ? $path1 : $path2)
		171
		172	Here, a path is selected randomly, and load is only called for one image,
		173	so keeps only one image in memory. If, on the next evaluation, luck
		174	decides to use the other path, then it will have to load that image again.
		175
126	=head2 REFERENCE	176	=head1 REFERENCE
127		177
128	=head3 COMMAND LINE SWITCHES	178	=head2 COMMAND LINE SWITCHES
129		179
130	=over 4	180	=over 4
131		181
132	=item --background-expr perl-expression	182	=item --background-expr perl-expression
133		183
…		…
139	overwriting borders and any other areas, such as the scrollbar.	189	overwriting borders and any other areas, such as the scrollbar.
140		190
141	Specifying this flag changes the behaviour, so that the image only	191	Specifying this flag changes the behaviour, so that the image only
142	replaces the background of the character area.	192	replaces the background of the character area.
143		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
144	=back	203	=back
145		204
146	=cut	205	=cut
147		206
148	our $EXPR;#d#	207	our %_IMG_CACHE;
149	#$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;	208	our $HOME;
162	our ($self, $old, $new);	209	our ($self, $old, $new);
163	our ($x, $y, $w, $h);	210	our ($x, $y, $w, $h);
164		211
165	# enforce at least this interval between updates	212	# enforce at least this interval between updates
166	our $MIN_INTERVAL = 1/100;	213	our $MIN_INTERVAL = 6/59.951;
167		214
168	{	215	{
169	package urxvt::bgdsl; # background language	216	package urxvt::bgdsl; # background language
		217
		218	use List::Util qw(min max sum shuffle);
170		219
171	=head2 PROVIDERS/GENERATORS	220	=head2 PROVIDERS/GENERATORS
172		221
173	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
174	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
…		…
179	=item load $path	228	=item load $path
180		229
181	Loads the image at the given C<$path>. The image is set to plane tiling	230	Loads the image at the given C<$path>. The image is set to plane tiling
182	mode.	231	mode.
183		232
184	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>).
185		235
		236	=item load_uc $path
		237
		238	Load uncached - same as load, but does not cache the image. This function
		239	is most useufl if you want to optimise a background expression in some
		240	way.
		241
186	=cut	242	=cut
		243
		244	sub load_uc($) {
		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	$img
		251	}
		252	}
187		253
188	sub load($) {	254	sub load($) {
189	my ($path) = @_;	255	my ($path) = @_;
190		256
191	$new->{load}{$path} = $old->{load}{$path} \|\| $self->new_img_from_file ($path);	257	$new->{load}{$path} = $old->{load}{$path} \|\| load_uc $path;
192	}	258	}
193		259
194	=item root	260	=item root
195		261
196	Returns the root window pixmap, that is, hopefully, the background image	262	Returns the root window pixmap, that is, hopefully, the background image
197	of your screen. The image is set to extend mode.	263	of your screen.
198		264
199	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
200	reevaluated when the bg image changes.	266	reevaluated when the bg image changes.
201		267
202	=cut	268	=cut
203		269
204	sub root() {	270	sub root() {
205	$new->{rootpmap_sensitive} = 1;	271	$new->{again}{rootpmap} = 1;
206	die "root op not supported, exg, we need you";	272	$self->new_img_from_root
207	}	273	}
208		274
209	=item solid $colour	275	=item solid $colour
210		276
211	=item solid $width, $height, $colour	277	=item solid $width, $height, $colour
212		278
213	Creates a new image and completely fills it with the given colour. The	279	Creates a new image and completely fills it with the given colour. The
214	image is set to tiling mode.	280	image is set to tiling mode.
215		281
216	If <$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
217	useful for solid backgrounds or for use in filtering effects.	283	useful for solid backgrounds or for use in filtering effects.
218		284
219	=cut	285	=cut
220		286
221	sub solid($$;$) {	287	sub solid($;$$) {
222	my $colour = pop;	288	my $colour = pop;
223		289
224	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);
225	$img->fill ($colour);	291	$img->fill ($colour);
226	$img	292	$img
227	}	293	}
228		294
229	=back	295	=item clone $img
230		296
231	=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.
232		299
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	300	=cut
274		301
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} = $_[0];
308	}
309
310	sub counter($) {	302	sub clone($) {
311	$new->{again} = $_[0];	303	$_[0]->clone
312	$self->{counter} + 0
313	}	304	}
314		305
315	=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	}
316		349
317	=head2 TILING MODES	350	=head2 TILING MODES
318		351
319	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
320	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.
…		…
350	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
351	image over another image or the background colour while leaving all	384	image over another image or the background colour while leaving all
352	background pixels outside the image unchanged.	385	background pixels outside the image unchanged.
353		386
354	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
355	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
356	in alpha mode, else background colour).	389	in alpha mode, else background colour).
357		390
358	pad load "mybg.png"	391	pad load "mybg.png"
359		392
360	=item extend $img	393	=item extend $img
361		394
362	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
363	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
364	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
365	same values as the pixels near the edge.	398	same values as the pixels near the edge.
366		399
367	Example: just for curiosity, how does this pixel extension stuff work?	400	Example: just for curiosity, how does this pixel extension stuff work?
368		401
…		…
394	$img	427	$img
395	}	428	}
396		429
397	=back	430	=back
398		431
399	=head2 PIXEL OPERATORS	432	=head2 VARIABLE VALUES
400		433
401	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.
402		439
403	=over 4	440	=over 4
404		441
405	=item clone $img	442	=item TX
406		443
407	Returns an exact copy of the image.	444	=item TY
408		445
409	=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).
410		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} = $_[0];
		510	}
		511
411	sub clone($) {	512	sub counter($) {
412	$_[0]->clone	513	$new->{again}{time} = $_[0];
		514	$self->{counter} + 0
413	}	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
414		524
415	=item clip $img	525	=item clip $img
416		526
417	=item clip $width, $height, $img	527	=item clip $width, $height, $img
418		528
…		…
442	$img->sub_rect ($_[0], $_[1], $w, $h)	552	$img->sub_rect ($_[0], $_[1], $w, $h)
443	}	553	}
444		554
445	=item scale $img	555	=item scale $img
446		556
447	=item scale $size_percent, $img	557	=item scale $size_factor, $img
448		558
449	=item scale $width_percent, $height_percent, $img	559	=item scale $width_factor, $height_factor, $img
450		560
451	Scales the image by the given percentages in horizontal	561	Scales the image by the given factors in horizontal
452	(C<$width_percent>) and vertical (C<$height_percent>) direction.	562	(C<$width>) and vertical (C<$height>) direction.
453		563
454	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.
455		565
456	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
457	keeping aspect.	567	keeping aspect.
458		568
459	=item resize $width, $height, $img	569	=item resize $width, $height, $img
460		570
461	Resizes the image to exactly C<$width> times C<$height> pixels.	571	Resizes the image to exactly C<$width> times C<$height> pixels.
462		572
463	=cut	573	=item fit $img
464		574
465	#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, $img
		584
		585	Similar to C<fit>, but shrinks or grows until all of the area is covered
		586	by the image, so instead of potentially leaving borders, it will cut off
		587	image data that doesn't fit.
		588
		589	=cut
466		590
467	sub scale($;$;$) {	591	sub scale($;$;$) {
468	my $img = pop;	592	my $img = pop;
469		593
470	@_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01)	594	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
471	: @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01)	595	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
472	: $img->scale (TW, TH)	596	: $img->scale (TW, TH)
473	}	597	}
474		598
475	sub resize($$$) {	599	sub resize($$$) {
476	my $img = pop;	600	my $img = pop;
477	$img->scale ($_[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
478	}	616	}
479		617
480	=item move $dx, $dy, $img	618	=item move $dx, $dy, $img
481		619
482	Moves the image by C<$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
483	the vertical.	621	the vertical.
484		622
485	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.
486		624
487	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"
488		649
489	=item rootalign $img	650	=item rootalign $img
490		651
491	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
492	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
…		…
498	rootalign mirror load "mybg.png"	659	rootalign mirror load "mybg.png"
499		660
500	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
501	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.
502		663
503	rootalign root	664	rootalign root
504		665
505	=cut	666	=cut
506		667
507	sub move($$;$) {	668	sub move($$;$) {
508	my $img = pop->clone;	669	my $img = pop->clone;
509	$img->move ($_[0], $_[1]);	670	$img->move ($_[0], $_[1]);
510	$img	671	$img
511	}	672	}
512		673
		674	sub align($;$$) {
		675	my $img = pop;
		676
		677	move $_[0] * (TW - $img->w),
		678	$_[1] * (TH - $img->h),
		679	$img
		680	}
		681
		682	sub center($;$$) {
		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), $img
		688	}
		689
513	sub rootalign($) {	690	sub rootalign($) {
514	move -TX, -TY, $_[0]	691	move -TX, -TY, $_[0]
515	}	692	}
516		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
517	=item contrast $factor, $img	723	=item contrast $factor, $img
518		724
519	=item contrast $r, $g, $b, $img	725	=item contrast $r, $g, $b, $img
520		726
521	=item contrast $r, $g, $b, $a, $img	727	=item contrast $r, $g, $b, $a, $img
522		728
523	Adjusts the I<contrast> of an image.	729	Adjusts the I<contrast> of an image.
524		730
		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.
		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
525	=item brightness $factor, $img	742	=item brightness $bias, $img
526		743
527	=item brightness $r, $g, $b, $img	744	=item brightness $r, $g, $b, $img
528		745
529	=item brightness $r, $g, $b, $a, $img	746	=item brightness $r, $g, $b, $a, $img
530		747
		748	Adjusts the brightness of an image.
		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
531	=cut	761	=cut
532		762
533	sub contrast($$;$$;$) {	763	sub contrast($$;$$;$) {
534	my $img = pop;	764	my $img = pop;
535	my ($r, $g, $b, $a) = @_;	765	my ($r, $g, $b, $a) = @_;
536		766
537	($g, $b) = ($r, $r) if @_ < 4;	767	($g, $b) = ($r, $r) if @_ < 3;
538	$a = 1 if @_ < 5;	768	$a = 1 if @_ < 4;
539		769
540	$img = $img->clone;	770	$img = $img->clone;
541	$img->contrast ($r, $g, $b, $a);	771	$img->contrast ($r, $g, $b, $a);
542	$img	772	$img
543	}	773	}
544		774
545	sub brightness($$;$$;$) {	775	sub brightness($$;$$;$) {
546	my $img = pop;	776	my $img = pop;
547	my ($r, $g, $b, $a) = @_;	777	my ($r, $g, $b, $a) = @_;
548		778
549	($g, $b) = ($r, $r) if @_ < 4;	779	($g, $b) = ($r, $r) if @_ < 3;
550	$a = 1 if @_ < 5;	780	$a = 1 if @_ < 4;
551		781
552	$img = $img->clone;	782	$img = $img->clone;
553	$img->brightness ($r, $g, $b, $a);	783	$img->brightness ($r, $g, $b, $a);
554	$img	784	$img
555	}	785	}
556		786
		787	=item blur $radius, $img
		788
		789	=item blur $radius_horz, $radius_vert, $img
		790
		791	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
		792	can also be specified separately.
		793
		794	Blurring is often I<very> slow, at least compared or other
		795	operators. Larger blur radii are slower than smaller ones, too, so if you
		796	don't want to freeze your screen for long times, start experimenting with
		797	low values for radius (<5).
		798
		799	=cut
		800
557	sub blur($$;$) {	801	sub blur($$;$) {
558	my $img = pop;	802	my $img = pop;
559	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	803	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
560	}	804	}
561		805
562	sub rotate($$$$$$) {	806	=back
563	my $img = pop;	807
564	$img->rotate (	808	=head2 OTHER STUFF
565	$_[0],	809
566	$_[1],	810	Anything that didn't fit any of the other categories, even after applying
567	$_[2] * $img->w * .01,	811	force and closing our eyes.
568	$_[3] * $img->h * .01,	812
569	$_[4] * (3.14159265 / 180),	813	=over 4
		814
		815	=item once { ... }
		816
		817	This function takes a code block as argument, that is, one or more
		818	statements enclosed by braces.
		819
		820	The trick is that this code block is only evaluated once - future calls
		821	will simply return the original image (yes, it should only be used with
		822	images).
		823
		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]
570	)	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 $self->{once_cache};
571	}	867	}
572		868
573	=back	869	=back
574		870
575	=cut	871	=cut
…		…
616	($x, $y, $w, $h) =	912	($x, $y, $w, $h) =
617	$self->background_geometry ($self->{border});	913	$self->background_geometry ($self->{border});
618		914
619	# evaluate user expression	915	# evaluate user expression
620		916
621	my $img = eval { $self->{expr}->() };	917	my $img = eval { urxvt::bgdsl::merge $self->{expr}->() };
622	warn $@ if $@;#d#	918	die $@ if $@;
623	die if !UNIVERSAL::isa $img, "urxvt::img";	919	die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";
624		920
625	$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
626	if $img->repeat_mode != urxvt::RepeatNormal;	926	if $img->repeat_mode != urxvt::RepeatNormal;
627		927
628	# if the expression is sensitive to external events, prepare reevaluation then
629
630	my $repeat;
631
632	if (my $again = $state->{again}) {	928	if (my $again = $again->{time}) {
633	$repeat = 1;
634	my $self = $self;	929	my $self = $self;
635	$state->{timer} = $again == $old->{again}	930	$state->{timer} = $again == $old->{again}
636	? $old->{timer}	931	? $old->{timer}
637	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {	932	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
638	++$self->{counter};	933	++$self->{counter};
639	$self->recalculate	934	$self->recalculate
640	});	935	});
641	}	936	}
642		937
643	if (delete $state->{position_sensitive}) {	938	if ($again->{position}) {
644	$repeat = 1;
645	$self->enable (position_change => sub { $_[0]->recalculate });	939	$self->enable (position_change => sub { $_[0]->recalculate });
646	} else {	940	} else {
647	$self->disable ("position_change");	941	$self->disable ("position_change");
648	}	942	}
649		943
650	if (delete $state->{size_sensitive}) {	944	if ($again->{size}) {
651	$repeat = 1;
652	$self->enable (size_change => sub { $_[0]->recalculate });	945	$self->enable (size_change => sub { $_[0]->recalculate });
653	} else {	946	} else {
654	$self->disable ("size_change");	947	$self->disable ("size_change");
655	}	948	}
656		949
657	if (delete $state->{rootpmap_sensitive}) {	950	if ($again->{rootpmap}) {
658	$repeat = 1;
659	$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	});
660	} else {	955	} else {
661	$self->disable ("rootpmap_change");	956	$self->disable ("rootpmap_change");
662	}	957	}
663		958
664	# clear stuff we no longer need	959	# clear stuff we no longer need
665		960
666	%$old = ();	961	%$old = ();
667		962
668	unless ($repeat) {	963	unless (%$again) {
669	delete $self->{state};	964	delete $self->{state};
670	delete $self->{expr};	965	delete $self->{expr};
671	}	966	}
672		967
673	# set background pixmap	968	# set background pixmap
…		…
678	}	973	}
679		974
680	sub on_start {	975	sub on_start {
681	my ($self) = @_;	976	my ($self) = @_;
682		977
683	my $expr = $self->x_resource ("background.expr")	978	my $expr = $self->x_resource ("%.expr")
684	or return;	979	or return;
685		980
		981	$self->has_render
		982	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		983
686	$self->set_expr (parse_expr $expr);	984	$self->set_expr (parse_expr $expr);
687	$self->{border} = $self->x_resource_boolean ("background.border");	985	$self->{border} = $self->x_resource_boolean ("%.border");
		986
		987	$MIN_INTERVAL = $self->x_resource ("%.interval");
688		988
689	()	989	()
690	}	990	}
691		991

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

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.37 by root, Fri Jun 8 20:35:43 2012 UTC vs.
Revision 1.62 by root, Sun Jun 17 21:58:18 2012 UTC