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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.36 by root, Fri Jun 8 20:23:09 2012 UTC vs.
Revision 1.71 by root, Mon Jul 2 01:40:41 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
24	to be as simple as possible.	26	to be as simple as possible.
25		27
26	For example, to load an image and scale it to the window size, you would	28	For example, to load an image and scale it to the window size, you would
27	use:	29	use:
28		30
29	urxvt --background-expr 'scale load "/path/to/mybg.png"'	31	urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
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 keep { 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.
…		…
51	If any of the parameters that the expression relies on changes (when the	53	If any of the parameters that the expression relies on changes (when the
52	window is moved or resized, its position or size changes; when the root	54	window is moved or resized, its position or size changes; when the root
53	pixmap is replaced by another one the root background changes; or when the	55	pixmap is replaced by another one the root background changes; or when the
54	timer elapses), then the expression will be evaluated again.	56	timer elapses), then the expression will be evaluated again.
55		57
56	For example, an expression such as C<scale load "$HOME/mybg.png"> scales the	58	For example, an expression such as C<scale keep { load "$HOME/mybg.png"
57	image to the window size, so it relies on the window size and will	59	}> scales the image to the window size, so it relies on the window size
58	be reevaluated each time it is changed, but not when it moves for	60	and will 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
		69	scale keep {
67	again 3600;	70	again 3600;
68	if (localtime now)[6]) {	71	if (localtime now)[6]) {
69	return scale load "$HOME/weekday.png";	72	return load "$HOME/weekday.png";
70	} else {	73	} else {
71	return scale load "$HOME/sunday.png";	74	return load "$HOME/sunday.png";
		75	}
72	}	76	}
73		77
74	This expression gets evaluated once per hour. It will set F<sunday.png> as	78	This inner expression is evaluated once per hour (and whenever the
		79	temrinal window is resized). It sets F<sunday.png> as background on
75	background on sundays, and F<weekday.png> on all other days.	80	Sundays, and F<weekday.png> on all other days.
76		81
77	Fortunately, we expect that most expressions will be much simpler, with	82	Fortunately, we expect that most expressions will be much simpler, with
78	little Perl knowledge needed.	83	little Perl knowledge needed.
79		84
80	Basically, you always start with a function that "generates" an image	85	Basically, you always start with a function that "generates" an image
…		…
97	its result becomes the argument to the C<scale> function.	102	its result becomes the argument to the C<scale> function.
98		103
99	Many operators also allow some parameters preceding the input image	104	Many operators also allow some parameters preceding the input image
100	that modify its behaviour. For example, C<scale> without any additional	105	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	106	arguments scales the image to size of the terminal window. If you specify
102	an additional argument, it uses it as a percentage:	107	an additional argument, it uses it as a scale factor (multiply by 100 to
		108	get a percentage):
103		109
104	scale 200, load "$HOME/mypic.png"	110	scale 2, load "$HOME/mypic.png"
105		111
106	This enlarges the image by a factor of 2 (200%). As you can see, C<scale>	112	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	113	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	114	C<load> only has one argument. Arguments are separated from each other by
109	commas.	115	commas.
110		116
111	Scale also accepts two arguments, which are then separate factors for both	117	Scale also accepts two arguments, which are then separate factors for both
112	horizontal and vertical dimensions. For example, this halves the image	118	horizontal and vertical dimensions. For example, this halves the image
113	width and doubles the image height:	119	width and doubles the image height:
114		120
115	scale 50, 200, load "$HOME/mypic.png"	121	scale 0.5, 2, load "$HOME/mypic.png"
116		122
117	TODO	123	IF you try out these expressions, you might suffer from some sluggishness,
		124	because each time the terminal is resized, it loads the PNG image agin
		125	and scales it. Scaling is usually fast (and unavoidable), but loading the
		126	image can be quite time consuming. This is where C<keep> comes in handy:
118		127
119	=head3 CYCLES AND CACHING	128	scale 0.5, 2, keep { load "$HOME/mypic.png" }
120		129
121	TODO	130	The C<keep> operator executes all the statements inside the braces only
		131	once, or when it thinks the outcome might change. In other cases it
		132	returns the last value computed by the brace block.
122		133
123	Each time the expression is reevaluated, a new cycle is said to have begun. Many operators	134	This means that the C<load> is only executed once, which makes it much
124	cache their results till the next cycle. For example	135	faster, but also means that more memory is being used, because the loaded
		136	image must be kept in memory at all times. In this expression, the
		137	trade-off is likely worth it.
125		138
		139	But back to effects: Other effects than scaling are also readily
		140	available, for example, you can tile the image to fill the whole window,
		141	instead of resizing it:
		142
		143	tile keep { load "$HOME/mypic.png" }
		144
		145	In fact, images returned by C<load> are in C<tile> mode by default, so the
		146	C<tile> operator is kind of superfluous.
		147
		148	Another common effect is to mirror the image, so that the same edges
		149	touch:
		150
		151	mirror keep { load "$HOME/mypic.png" }
		152
		153	Another common background expression is:
		154
		155	rootalign root
		156
		157	This one first takes a snapshot of the screen background image, and then
		158	moves it to the upper left corner of the screen (as opposed to the upper
		159	left corner of the terminal window)- the result is pseudo-transparency:
		160	the image seems to be static while the window is moved around.
		161
		162	=head2 COLOUR SPECIFICATIONS
		163
		164	Whenever an oprator expects a "colour", then this can be specified in one
		165	of two ways: Either as string with an X11 colour specification, such as:
		166
		167	"red" # named colour
		168	"#f00" # simple rgb
		169	"[50]red" # red with 50% alpha
		170	"TekHVC:300/50/50" # anything goes
		171
		172	OR as an array reference with one, three or four components:
		173
		174	[0.5] # 50% gray, 100% alpha
		175	[0.5, 0, 0] # dark red, no green or blur, 100% alpha
		176	[0.5, 0, 0, 0.7] # same with explicit 70% alpha
		177
		178	=head2 CACHING AND SENSITIVITY
		179
		180	Since some operations (such as C<load> and C<blur>) can take a long time,
		181	caching results can be very important for a smooth operation. Caching can
		182	also be useful to reduce memory usage, though, for example, when an image
		183	is cached by C<load>, it could be shared by multiple terminal windows
		184	running inside urxvtd.
		185
		186	=head3 C<keep { ... }> caching
		187
		188	The most important way to cache expensive operations is to use C<keep {
		189	... }>. The C<keep> operator takes a block of multiple statements enclosed
		190	by C<{}> and keeps the return value in memory.
		191
		192	An expression can be "sensitive" to various external events, such as
		193	scaling or moving the window, root background changes and timers. Simply
		194	using an expression (such as C<scale> without parameters) that depends on
		195	certain changing values (called "variables"), or using those variables
		196	directly, will make an expression sensitive to these events - for example,
		197	using C<scale> or C<TW> will make the expression sensitive to the terminal
		198	size, and thus to resizing events.
		199
		200	When such an event happens, C<keep> will automatically trigger a
		201	reevaluation of the whole expression with the new value of the expression.
		202
		203	C<keep> is most useful for expensive operations, such as C<blur>:
		204
		205	rootalign keep { blur 20, root }
		206
		207	This makes a blurred copy of the root background once, and on subsequent
		208	calls, just root-aligns it. Since C<blur> is usually quite slow and
		209	C<rootalign> is quite fast, this trades extra memory (for the cached
		210	blurred pixmap) with speed (blur only needs to be redone when root
		211	changes).
		212
		213	=head3 C<load> caching
		214
		215	The C<load> operator itself does not keep images in memory, but as long as
		216	the image is still in memory, C<load> will use the in-memory image instead
		217	of loading it freshly from disk.
		218
		219	That means that this expression:
		220
		221	keep { load "$HOME/path..." }
		222
		223	Not only caches the image in memory, other terminal instances that try to
		224	C<load> it can reuse that in-memory copy.
		225
126	=head2 REFERENCE	226	=head1 REFERENCE
127		227
128	=head3 COMMAND LINE SWITCHES	228	=head2 COMMAND LINE SWITCHES
129		229
130	=over 4	230	=over 4
131		231
132	=item --background-expr perl-expression	232	=item --background-expr perl-expression
133		233
…		…
139	overwriting borders and any other areas, such as the scrollbar.	239	overwriting borders and any other areas, such as the scrollbar.
140		240
141	Specifying this flag changes the behaviour, so that the image only	241	Specifying this flag changes the behaviour, so that the image only
142	replaces the background of the character area.	242	replaces the background of the character area.
143		243
		244	=item --background-interval seconds
		245
		246	Since some operations in the underlying XRender extension can effectively
		247	freeze your X-server for prolonged time, this extension enforces a minimum
		248	time between updates, which is normally about 0.1 seconds.
		249
		250	If you want to do updates more often, you can decrease this safety
		251	interval with this switch.
		252
144	=back	253	=back
145		254
146	=cut	255	=cut
147		256
148	our $EXPR;#d#	257	our %_IMG_CACHE;
149	#$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;	258	our $HOME;
162	our ($self, $old, $new);	259	our ($self, $frame);
163	our ($x, $y, $w, $h);	260	our ($x, $y, $w, $h);
164		261
165	# enforce at least this interval between updates	262	# enforce at least this interval between updates
166	our $MIN_INTERVAL = 1/100;	263	our $MIN_INTERVAL = 6/59.951;
167		264
168	{	265	{
169	package urxvt::bgdsl; # background language	266	package urxvt::bgdsl; # background language
		267
		268	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
		269	sub FR_CACHE () { 1 } # cached values
		270	sub FR_AGAIN () { 2 } # what this expr is sensitive to
		271	sub FR_STATE () { 3 } # watchers etc.
		272
		273	use List::Util qw(min max sum shuffle);
170		274
171	=head2 PROVIDERS/GENERATORS	275	=head2 PROVIDERS/GENERATORS
172		276
173	These functions provide an image, by loading it from disk, grabbing it	277	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	278	from the root screen or by simply generating it. They are used as starting
…		…
179	=item load $path	283	=item load $path
180		284
181	Loads the image at the given C<$path>. The image is set to plane tiling	285	Loads the image at the given C<$path>. The image is set to plane tiling
182	mode.	286	mode.
183		287
184	Loaded images will be cached for one cycle.	288	If the image is already in memory (e.g. because another terminal instance
		289	uses it), then the in-memory copy us returned instead.
		290
		291	=item load_uc $path
		292
		293	Load uncached - same as load, but does not cache the image, which means it
		294	is I<always> loaded from the filesystem again.
185		295
186	=cut	296	=cut
187		297
188	sub load($) {	298	sub load($) {
189	my ($path) = @_;	299	my ($path) = @_;
190		300
191	$new->{load}{$path} = $old->{load}{$path} \|\| $self->new_img_from_file ($path);	301	$_IMG_CACHE{$path} \|\| do {
		302	my $img = $self->new_img_from_file ($path);
		303	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		304	$img
		305	}
192	}	306	}
193		307
194	=item root	308	=item root
195		309
196	Returns the root window pixmap, that is, hopefully, the background image	310	Returns the root window pixmap, that is, hopefully, the background image
197	of your screen. The image is set to extend mode.	311	of your screen.
198		312
199	This function makes your expression root sensitive, that means it will be	313	This function makes your expression root sensitive, that means it will be
200	reevaluated when the bg image changes.	314	reevaluated when the bg image changes.
201		315
202	=cut	316	=cut
203		317
204	sub root() {	318	sub root() {
205	$new->{rootpmap_sensitive} = 1;	319	$frame->[FR_AGAIN]{rootpmap} = 1;
206	die "root op not supported, exg, we need you";	320	$self->new_img_from_root
207	}	321	}
208		322
209	=item solid $colour	323	=item solid $colour
210		324
211	=item solid $width, $height, $colour	325	=item solid $width, $height, $colour
212		326
213	Creates a new image and completely fills it with the given colour. The	327	Creates a new image and completely fills it with the given colour. The
214	image is set to tiling mode.	328	image is set to tiling mode.
215		329
216	If <$width> and C<$height> are omitted, it creates a 1x1 image, which is	330	If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
217	useful for solid backgrounds or for use in filtering effects.	331	useful for solid backgrounds or for use in filtering effects.
218		332
219	=cut	333	=cut
220		334
221	sub solid($$;$) {	335	sub solid($;$$) {
222	my $colour = pop;	336	my $colour = pop;
223		337
224	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	338	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
225	$img->fill ($colour);	339	$img->fill ($colour);
226	$img	340	$img
227	}	341	}
228		342
229	=back	343	=item clone $img
230		344
231	=head2 VARIABLES	345	Returns an exact copy of the image. This is useful if you want to have
		346	multiple copies of the same image to apply different effects to.
232		347
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	348	=cut
274		349
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} = $_[0];
308	}
309
310	sub counter($) {	350	sub clone($) {
311	$new->{again} = $_[0];	351	$_[0]->clone
312	$self->{counter} + 0
313	}	352	}
314		353
315	=back	354	=item merge $img ...
		355
		356	Takes any number of images and merges them together, creating a single
		357	image containing them all. The tiling mode of the first image is used as
		358	the tiling mode of the resulting image.
		359
		360	This function is called automatically when an expression returns multiple
		361	images.
		362
		363	=cut
		364
		365	sub merge(@) {
		366	return $_[0] unless $#_;
		367
		368	# rather annoyingly clumsy, but optimisation is for another time
		369
		370	my $x0 = +1e9;
		371	my $y0 = +1e9;
		372	my $x1 = -1e9;
		373	my $y1 = -1e9;
		374
		375	for (@_) {
		376	my ($x, $y, $w, $h) = $_->geometry;
		377
		378	$x0 = $x if $x0 > $x;
		379	$y0 = $y if $y0 > $y;
		380
		381	$x += $w;
		382	$y += $h;
		383
		384	$x1 = $x if $x1 < $x;
		385	$y1 = $y if $y1 < $y;
		386	}
		387
		388	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		389	$base->repeat_mode ($_[0]->repeat_mode);
		390	$base->fill ([0, 0, 0, 0]);
		391
		392	$base->draw ($_)
		393	for @_;
		394
		395	$base
		396	}
316		397
317	=head2 TILING MODES	398	=head2 TILING MODES
318		399
319	The following operators modify the tiling mode of an image, that is, the	400	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.	401	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	431	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	432	image over another image or the background colour while leaving all
352	background pixels outside the image unchanged.	433	background pixels outside the image unchanged.
353		434
354	Example: load an image and display it in the upper left corner. The rest	435	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	436	of the space is left "empty" (transparent or whatever your compositor does
356	in alpha mode, else background colour).	437	in alpha mode, else background colour).
357		438
358	pad load "mybg.png"	439	pad load "mybg.png"
359		440
360	=item extend $img	441	=item extend $img
361		442
362	Extends the image over the whole plane, using the closest pixel in the	443	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	444	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	445	filtering operations and want the pixels outside the image to have the
365	same values as the pixels near the edge.	446	same values as the pixels near the edge.
366		447
367	Example: just for curiosity, how does this pixel extension stuff work?	448	Example: just for curiosity, how does this pixel extension stuff work?
368		449
…		…
394	$img	475	$img
395	}	476	}
396		477
397	=back	478	=back
398		479
399	=head2 PIXEL OPERATORS	480	=head2 VARIABLE VALUES
400		481
401	The following operators modify the image pixels in various ways.	482	The following functions provide variable data such as the terminal window
		483	dimensions. They are not (Perl-) variables, they just return stuff that
		484	varies. Most of them make your expression sensitive to some events, for
		485	example using C<TW> (terminal width) means your expression is evaluated
		486	again when the terminal is resized.
402		487
403	=over 4	488	=over 4
404		489
405	=item clone $img	490	=item TX
406		491
407	Returns an exact copy of the image.	492	=item TY
408		493
409	=cut	494	Return the X and Y coordinates of the terminal window (the terminal
		495	window is the full window by default, and the character area only when in
		496	border-respect mode).
410		497
		498	Using these functions make your expression sensitive to window moves.
		499
		500	These functions are mainly useful to align images to the root window.
		501
		502	Example: load an image and align it so it looks as if anchored to the
		503	background (that's exactly what C<rootalign> does btw.):
		504
		505	move -TX, -TY, keep { load "mybg.png" }
		506
		507	=item TW
		508
		509	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		510	terminal window is the full window by default, and the character area only
		511	when in border-respect mode).
		512
		513	Using these functions make your expression sensitive to window resizes.
		514
		515	These functions are mainly useful to scale images, or to clip images to
		516	the window size to conserve memory.
		517
		518	Example: take the screen background, clip it to the window size, blur it a
		519	bit, align it to the window position and use it as background.
		520
		521	clip move -TX, -TY, keep { blur 5, root }
		522
		523	=cut
		524
		525	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
		526	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
		527	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
		528	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
		529
		530	=item now
		531
		532	Returns the current time as (fractional) seconds since the epoch.
		533
		534	Using this expression does I<not> make your expression sensitive to time,
		535	but the next two functions do.
		536
		537	=item again $seconds
		538
		539	When this function is used the expression will be reevaluated again in
		540	C<$seconds> seconds.
		541
		542	Example: load some image and rotate it according to the time of day (as if it were
		543	the hour pointer of a clock). Update this image every minute.
		544
		545	again 60;
		546	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
		547
		548	=item counter $seconds
		549
		550	Like C<again>, but also returns an increasing counter value, starting at
		551	0, which might be useful for some simple animation effects.
		552
		553	=cut
		554
		555	sub now() { urxvt::NOW }
		556
		557	sub again($) {
		558	$frame->[FR_AGAIN]{time} = $_[0];
		559	}
		560
411	sub clone($) {	561	sub counter($) {
412	$_[0]->clone	562	$frame->[FR_AGAIN]{time} = $_[0];
		563	$frame->[FR_STATE]{counter} + 0
413	}	564	}
		565
		566	=back
		567
		568	=head2 SHAPE CHANGING OPERATORS
		569
		570	The following operators modify the shape, size or position of the image.
		571
		572	=over 4
414		573
415	=item clip $img	574	=item clip $img
416		575
417	=item clip $width, $height, $img	576	=item clip $width, $height, $img
418		577
…		…
429	assumed.	588	assumed.
430		589
431	Example: load an image, blur it, and clip it to the window size to save	590	Example: load an image, blur it, and clip it to the window size to save
432	memory.	591	memory.
433		592
434	clip blur 10, load "mybg.png"	593	clip keep { blur 10, load "mybg.png" }
435		594
436	=cut	595	=cut
437		596
438	sub clip($;$$;$$) {	597	sub clip($;$$;$$) {
439	my $img = pop;	598	my $img = pop;
…		…
442	$img->sub_rect ($_[0], $_[1], $w, $h)	601	$img->sub_rect ($_[0], $_[1], $w, $h)
443	}	602	}
444		603
445	=item scale $img	604	=item scale $img
446		605
447	=item scale $size_percent, $img	606	=item scale $size_factor, $img
448		607
449	=item scale $width_percent, $height_percent, $img	608	=item scale $width_factor, $height_factor, $img
450		609
451	Scales the image by the given percentages in horizontal	610	Scales the image by the given factors in horizontal
452	(C<$width_percent>) and vertical (C<$height_percent>) direction.	611	(C<$width>) and vertical (C<$height>) direction.
453		612
454	If only one percentage is give, it is used for both directions.	613	If only one factor is give, it is used for both directions.
455		614
456	If no percentages are given, scales the image to the window size without	615	If no factors are given, scales the image to the window size without
457	keeping aspect.	616	keeping aspect.
458		617
459	=item resize $width, $height, $img	618	=item resize $width, $height, $img
460		619
461	Resizes the image to exactly C<$width> times C<$height> pixels.	620	Resizes the image to exactly C<$width> times C<$height> pixels.
462		621
463	=cut	622	=item fit $img
464		623
465	#TODO: maximise, maximise_fill?	624	=item fit $width, $height, $img
		625
		626	Fits the image into the given C<$width> and C<$height> without changing
		627	aspect, or the terminal size. That means it will be shrunk or grown until
		628	the whole image fits into the given area, possibly leaving borders.
		629
		630	=item cover $img
		631
		632	=item cover $width, $height, $img
		633
		634	Similar to C<fit>, but shrinks or grows until all of the area is covered
		635	by the image, so instead of potentially leaving borders, it will cut off
		636	image data that doesn't fit.
		637
		638	=cut
466		639
467	sub scale($;$;$) {	640	sub scale($;$;$) {
468	my $img = pop;	641	my $img = pop;
469		642
470	@_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01)	643	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
471	: @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01)	644	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
472	: $img->scale (TW, TH)	645	: $img->scale (TW, TH)
473	}	646	}
474		647
475	sub resize($$$) {	648	sub resize($$$) {
476	my $img = pop;	649	my $img = pop;
477	$img->scale ($_[0], $_[1])	650	$img->scale ($_[0], $_[1])
478	}	651	}
479		652
		653	sub fit($;$$) {
		654	my $img = pop;
		655	my $w = ($_[0] \|\| TW) / $img->w;
		656	my $h = ($_[1] \|\| TH) / $img->h;
		657	scale +(min $w, $h), $img
		658	}
		659
		660	sub cover($;$$) {
		661	my $img = pop;
		662	my $w = ($_[0] \|\| TW) / $img->w;
		663	my $h = ($_[1] \|\| TH) / $img->h;
		664	scale +(max $w, $h), $img
		665	}
		666
480	=item move $dx, $dy, $img	667	=item move $dx, $dy, $img
481		668
482	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in	669	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
483	the vertical.	670	the vertical.
484		671
485	Example: move the image right by 20 pixels and down by 30.	672	Example: move the image right by 20 pixels and down by 30.
486		673
487	move 20, 30, ...	674	move 20, 30, ...
		675
		676	=item align $xalign, $yalign, $img
		677
		678	Aligns the image according to a factor - C<0> means the image is moved to
		679	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		680	exactly centered and C<1> means it touches the right or bottom edge.
		681
		682	Example: remove any visible border around an image, center it vertically but move
		683	it to the right hand side.
		684
		685	align 1, 0.5, pad $img
		686
		687	=item center $img
		688
		689	=item center $width, $height, $img
		690
		691	Centers the image, i.e. the center of the image is moved to the center of
		692	the terminal window (or the box specified by C<$width> and C<$height> if
		693	given).
		694
		695	Example: load an image and center it.
		696
		697	center keep { pad load "mybg.png" }
488		698
489	=item rootalign $img	699	=item rootalign $img
490		700
491	Moves the image so that it appears glued to the screen as opposed to the	701	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	702	window. This gives the illusion of a larger area behind the window. It is
493	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	703	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
494	top left of the screen.	704	top left of the screen.
495		705
496	Example: load a background image, put it in mirror mode and root align it.	706	Example: load a background image, put it in mirror mode and root align it.
497		707
498	rootalign mirror load "mybg.png"	708	rootalign keep { mirror load "mybg.png" }
499		709
500	Example: take the screen background and align it, giving the illusion of	710	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.	711	transparency as long as the window isn't in front of other windows.
502		712
503	rootalign root	713	rootalign root
504		714
505	=cut	715	=cut
506		716
507	sub move($$;$) {	717	sub move($$;$) {
508	my $img = pop->clone;	718	my $img = pop->clone;
509	$img->move ($_[0], $_[1]);	719	$img->move ($_[0], $_[1]);
510	$img	720	$img
511	}	721	}
512		722
		723	sub align($;$$) {
		724	my $img = pop;
		725
		726	move $_[0] * (TW - $img->w),
		727	$_[1] * (TH - $img->h),
		728	$img
		729	}
		730
		731	sub center($;$$) {
		732	my $img = pop;
		733	my $w = $_[0] \|\| TW;
		734	my $h = $_[1] \|\| TH;
		735
		736	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		737	}
		738
513	sub rootalign($) {	739	sub rootalign($) {
514	move -TX, -TY, $_[0]	740	move -TX, -TY, $_[0]
515	}	741	}
516		742
		743	=item rotate $center_x, $center_y, $degrees, $img
		744
		745	Rotates the image clockwise by C<$degrees> degrees, around the point at
		746	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		747
		748	Example: rotate the image by 90 degrees around it's center.
		749
		750	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		751
		752	=cut
		753
		754	sub rotate($$$$) {
		755	my $img = pop;
		756	$img->rotate (
		757	$_[0] * ($img->w + $img->x),
		758	$_[1] * ($img->h + $img->y),
		759	$_[2] * (3.14159265 / 180),
		760	)
		761	}
		762
		763	=back
		764
		765	=head2 COLOUR MODIFICATIONS
		766
		767	The following operators change the pixels of the image.
		768
		769	=over 4
		770
		771	=item tint $color, $img
		772
		773	Tints the image in the given colour.
		774
		775	Example: tint the image red.
		776
		777	tint "red", load "rgb.png"
		778
		779	Example: the same, but specify the colour by component.
		780
		781	tint [1, 0, 0], load "rgb.png"
		782
		783	=cut
		784
		785	sub tint($$) {
		786	$_[1]->tint ($_[0])
		787	}
		788
517	=item contrast $factor, $img	789	=item contrast $factor, $img
518		790
519	=item contrast $r, $g, $b, $img	791	=item contrast $r, $g, $b, $img
520		792
521	=item contrast $r, $g, $b, $a, $img	793	=item contrast $r, $g, $b, $a, $img
522		794
523	Adjusts the I<contrast> of an image.	795	Adjusts the I<contrast> of an image.
524		796
		797	The first form applies a single C<$factor> to red, green and blue, the
		798	second form applies separate factors to each colour channel, and the last
		799	form includes the alpha channel.
		800
		801	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		802	contrast.
		803
		804	Due to limitations in the underlying XRender extension, lowering contrast
		805	also reduces brightness, while increasing contrast currently also
		806	increases brightness.
		807
525	=item brightness $factor, $img	808	=item brightness $bias, $img
526		809
527	=item brightness $r, $g, $b, $img	810	=item brightness $r, $g, $b, $img
528		811
529	=item brightness $r, $g, $b, $a, $img	812	=item brightness $r, $g, $b, $a, $img
		813
		814	Adjusts the brightness of an image.
		815
		816	The first form applies a single C<$bias> to red, green and blue, the
		817	second form applies separate biases to each colour channel, and the last
		818	form includes the alpha channel.
		819
		820	Values less than 0 reduce brightness, while values larger than 0 increase
		821	it. Useful range is from -1 to 1 - the former results in a black, the
		822	latter in a white picture.
		823
		824	Due to idiosyncrasies in the underlying XRender extension, biases less
		825	than zero can be I<very> slow.
530		826
531	=cut	827	=cut
532		828
533	sub contrast($$;$$;$) {	829	sub contrast($$;$$;$) {
534	my $img = pop;	830	my $img = pop;
535	my ($r, $g, $b, $a) = @_;	831	my ($r, $g, $b, $a) = @_;
536		832
537	($g, $b) = ($r, $r) if @_ < 4;	833	($g, $b) = ($r, $r) if @_ < 3;
538	$a = 1 if @_ < 5;	834	$a = 1 if @_ < 4;
539		835
540	$img = $img->clone;	836	$img = $img->clone;
541	# $img->contrast ($r, $g, $b, $a);	837	$img->contrast ($r, $g, $b, $a);
542	$img	838	$img
543	}	839	}
544		840
545	sub brightness($$;$$;$) {	841	sub brightness($$;$$;$) {
546	my $img = pop;	842	my $img = pop;
547	my ($r, $g, $b, $a) = @_;	843	my ($r, $g, $b, $a) = @_;
548		844
549	($g, $b) = ($r, $r) if @_ < 4;	845	($g, $b) = ($r, $r) if @_ < 3;
550	$a = 1 if @_ < 5;	846	$a = 1 if @_ < 4;
551		847
552	$img = $img->clone;	848	$img = $img->clone;
553	$img->brightness ($r, $g, $b, $a);	849	$img->brightness ($r, $g, $b, $a);
554	$img	850	$img
555	}	851	}
556		852
		853	=item blur $radius, $img
		854
		855	=item blur $radius_horz, $radius_vert, $img
		856
		857	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
		858	can also be specified separately.
		859
		860	Blurring is often I<very> slow, at least compared or other
		861	operators. Larger blur radii are slower than smaller ones, too, so if you
		862	don't want to freeze your screen for long times, start experimenting with
		863	low values for radius (<5).
		864
		865	=cut
		866
557	sub blur($$;$) {	867	sub blur($$;$) {
558	my $img = pop;	868	my $img = pop;
559	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	869	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
560	}	870	}
561		871
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	872	=back
574		873
		874	=head2 OTHER STUFF
		875
		876	Anything that didn't fit any of the other categories, even after applying
		877	force and closing our eyes.
		878
		879	=over 4
		880
		881	=item keep { ... }
		882
		883	This operator takes a code block as argument, that is, one or more
		884	statements enclosed by braces.
		885
		886	The trick is that this code block is only evaluated when the outcome
		887	changes - on other calls the C<keep> simply returns the image it computed
		888	previously (yes, it should only be used with images). Or in other words,
		889	C<keep> I<caches> the result of the code block so it doesn't need to be
		890	computed again.
		891
		892	This can be extremely useful to avoid redoing slow operations - for
		893	example, if your background expression takes the root background, blurs it
		894	and then root-aligns it it would have to blur the root background on every
		895	window move or resize.
		896
		897	Another example is C<load>, which can be quite slow.
		898
		899	In fact, urxvt itself encloses the whole expression in some kind of
		900	C<keep> block so it only is reevaluated as required.
		901
		902	Putting the blur into a C<keep> block will make sure the blur is only done
		903	once, while the C<rootalign> is still done each time the window moves.
		904
		905	rootlign keep { blur 10, root }
		906
		907	This leaves the question of how to force reevaluation of the block,
		908	in case the root background changes: If expression inside the block
		909	is sensitive to some event (root background changes, window geometry
		910	changes), then it will be reevaluated automatically as needed.
		911
		912	=cut
		913
		914	sub keep(&) {
		915	my $id = $_[0]+0;
		916
		917	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		918
		919	unless ($frame->[FR_CACHE]) {
		920	$frame->[FR_CACHE] = [ $_[0]() ];
		921
		922	my $self = $self;
		923	my $frame = $frame;
		924	Scalar::Util::weaken $frame;
		925	$self->compile_frame ($frame, sub {
		926	# clear this frame cache, also for all parents
		927	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		928	undef $frame->[FR_CACHE];
		929	}
		930
		931	$self->recalculate;
		932	});
		933	};
		934
		935	# in scalar context we always return the first original result, which
		936	# is not quite how perl works.
		937	wantarray
		938	? @{ $frame->[FR_CACHE] }
		939	: $frame->[FR_CACHE][0]
		940	}
		941
		942	# sub keep_clear() {
		943	# delete $self->{frame_cache};
		944	# }
		945
		946	=back
		947
575	=cut	948	=cut
576		949
577	}	950	}
578		951
579	sub parse_expr {	952	sub parse_expr {
580	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	953	my $expr = eval
		954	"sub {\n"
		955	. "package urxvt::bgdsl;\n"
		956	. "#line 0 'background expression'\n"
		957	. "$_[0]\n"
		958	. "}";
581	die if $@;	959	die if $@;
582	$expr	960	$expr
583	}	961	}
584		962
585	# compiles a parsed expression	963	# compiles a parsed expression
586	sub set_expr {	964	sub set_expr {
587	my ($self, $expr) = @_;	965	my ($self, $expr) = @_;
588		966
		967	$self->{root} = [];
589	$self->{expr} = $expr;	968	$self->{expr} = $expr;
590	$self->recalculate;	969	$self->recalculate;
		970	}
		971
		972	# takes a hash of sensitivity indicators and installs watchers
		973	sub compile_frame {
		974	my ($self, $frame, $cb) = @_;
		975
		976	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		977	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		978
		979	# don't keep stuff alive
		980	Scalar::Util::weaken $state;
		981
		982	if ($again->{nested}) {
		983	$state->{nested} = 1;
		984	} else {
		985	delete $state->{nested};
		986	}
		987
		988	if (my $interval = $again->{time}) {
		989	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		990	if $state->{time}[0] != $interval;
		991
		992	# callback might have changed, although we could just rule that out
		993	$state->{time}[1]->cb (sub {
		994	++$state->{counter};
		995	$cb->();
		996	});
		997	} else {
		998	delete $state->{time};
		999	}
		1000
		1001	if ($again->{position}) {
		1002	$state->{position} = $self->on (position_change => $cb);
		1003	} else {
		1004	delete $state->{position};
		1005	}
		1006
		1007	if ($again->{size}) {
		1008	$state->{size} = $self->on (size_change => $cb);
		1009	} else {
		1010	delete $state->{size};
		1011	}
		1012
		1013	if ($again->{rootpmap}) {
		1014	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		1015	} else {
		1016	delete $state->{rootpmap};
		1017	}
591	}	1018	}
592		1019
593	# evaluate the current bg expression	1020	# evaluate the current bg expression
594	sub recalculate {	1021	sub recalculate {
595	my ($arg_self) = @_;	1022	my ($arg_self) = @_;
…		…
605		1032
606	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1033	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
607		1034
608	# set environment to evaluate user expression	1035	# set environment to evaluate user expression
609		1036
610	local $self = $arg_self;	1037	local $self = $arg_self;
611
612	local $HOME = $ENV{HOME};	1038	local $HOME = $ENV{HOME};
613	local $old = $self->{state};	1039	local $frame = [];
614	local $new = my $state = $self->{state} = {};
615		1040
616	($x, $y, $w, $h) =
617	$self->background_geometry ($self->{border});	1041	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
618		1042
619	# evaluate user expression	1043	# evaluate user expression
620		1044
621	my $img = eval { $self->{expr}->() };	1045	my @img = eval { $self->{expr}->() };
622	warn $@ if $@;#d#	1046	die $@ if $@;
		1047	die "background-expr did not return anything.\n" unless @img;
		1048	die "background-expr: expected image(s), got something else.\n"
623	die if !UNIVERSAL::isa $img, "urxvt::img";	1049	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
624		1050
625	$state->{size_sensitive} = 1	1051	my $img = urxvt::bgdsl::merge @img;
		1052
		1053	$frame->[FR_AGAIN]{size} = 1
626	if $img->repeat_mode != urxvt::RepeatNormal;	1054	if $img->repeat_mode != urxvt::RepeatNormal;
627		1055
628	# if the expression is sensitive to external events, prepare reevaluation then	1056	# if the expression is sensitive to external events, prepare reevaluation then
629		1057	$self->compile_frame ($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	$self->disable ("rootpmap_change");
662	}
663		1058
664	# clear stuff we no longer need	1059	# clear stuff we no longer need
665		1060
666	%$old = ();	1061	# unless (%{ $frame->[FR_STATE] }) {
667
668	unless ($repeat) {
669	delete $self->{state};	1062	# delete $self->{state};
670	delete $self->{expr};	1063	# delete $self->{expr};
671	}	1064	# }
672		1065
673	# set background pixmap	1066	# set background pixmap
674		1067
675	$self->set_background ($img, $self->{border});	1068	$self->set_background ($img, $self->{border});
676	$self->scr_recolour (0);	1069	$self->scr_recolour (0);
…		…
678	}	1071	}
679		1072
680	sub on_start {	1073	sub on_start {
681	my ($self) = @_;	1074	my ($self) = @_;
682		1075
683	my $expr = $self->x_resource ("background.expr")	1076	my $expr = $self->x_resource ("%.expr")
684	or return;	1077	or return;
685		1078
		1079	$self->has_render
		1080	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1081
686	$self->set_expr (parse_expr $expr);	1082	$self->set_expr (parse_expr $expr);
687	$self->{border} = $self->x_resource_boolean ("background.border");	1083	$self->{border} = $self->x_resource_boolean ("%.border");
		1084
		1085	$MIN_INTERVAL = $self->x_resource ("%.interval");
688		1086
689	()	1087	()
690	}	1088	}
691		1089

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.36 by root, Fri Jun 8 20:23:09 2012 UTC vs. Revision 1.71 by root, Mon Jul 2 01:40:41 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.36 by root, Fri Jun 8 20:23:09 2012 UTC vs.
Revision 1.71 by root, Mon Jul 2 01:40:41 2012 UTC