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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.38 by root, Fri Jun 8 21:48:07 2012 UTC vs.
Revision 1.68 by root, Sun Jul 1 21:47:07 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 CACHING AND SENSITIVITY
		163
		164	Since some operations (such as C<load> and C<blur>) can take a long time,
		165	caching results can be very important for a smooth operation. Caching can
		166	also be useful to reduce memory usage, though, for example, when an image
		167	is cached by C<load>, it could be shared by multiple terminal windows
		168	running inside urxvtd.
		169
		170	=head3 C<keep { ... }> caching
		171
		172	The most important way to cache expensive operations is to use C<keep {
		173	... }>. The C<keep> operator takes a block of multiple statements enclosed
		174	by C<{}> and keeps the return value in memory.
		175
		176	An expression can be "sensitive" to various external events, such as
		177	scaling or moving the window, root background changes and timers. Simply
		178	using an expression (such as C<scale> without parameters) that depends on
		179	certain changing values (called "variables"), or using those variables
		180	directly, will make an expression sensitive to these events - for example,
		181	using C<scale> or C<TW> will make the expression sensitive to the terminal
		182	size, and thus to resizing events.
		183
		184	When such an event happens, C<keep> will automatically trigger a
		185	reevaluation of the whole expression with the new value of the expression.
		186
		187	C<keep> is most useful for expensive operations, such as C<blur>:
		188
		189	rootalign keep { blur 20, root }
		190
		191	This makes a blurred copy of the root background once, and on subsequent
		192	calls, just root-aligns it. Since C<blur> is usually quite slow and
		193	C<rootalign> is quite fast, this trades extra memory (for the cached
		194	blurred pixmap) with speed (blur only needs to be redone when root
		195	changes).
		196
		197	=head3 C<load> caching
		198
		199	The C<load> operator itself does not keep images in memory, but as long as
		200	the image is still in memory, C<load> will use the in-memory image instead
		201	of loading it freshly from disk.
		202
		203	That means that this expression:
		204
		205	keep { load "$HOME/path..." }
		206
		207	Not only caches the image in memory, other terminal instances that try to
		208	C<load> it can reuse that in-memory copy.
		209
126	=head2 REFERENCE	210	=head1 REFERENCE
127		211
128	=head3 COMMAND LINE SWITCHES	212	=head2 COMMAND LINE SWITCHES
129		213
130	=over 4	214	=over 4
131		215
132	=item --background-expr perl-expression	216	=item --background-expr perl-expression
133		217
…		…
139	overwriting borders and any other areas, such as the scrollbar.	223	overwriting borders and any other areas, such as the scrollbar.
140		224
141	Specifying this flag changes the behaviour, so that the image only	225	Specifying this flag changes the behaviour, so that the image only
142	replaces the background of the character area.	226	replaces the background of the character area.
143		227
		228	=item --background-interval seconds
		229
		230	Since some operations in the underlying XRender extension can effectively
		231	freeze your X-server for prolonged time, this extension enforces a minimum
		232	time between updates, which is normally about 0.1 seconds.
		233
		234	If you want to do updates more often, you can decrease this safety
		235	interval with this switch.
		236
144	=back	237	=back
145		238
146	=cut	239	=cut
147		240
148	our $EXPR;#d#	241	our %_IMG_CACHE;
149	#$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;	242	our $HOME;
162	our ($self, $old, $new);	243	our ($self, $frame);
163	our ($x, $y, $w, $h);	244	our ($x, $y, $w, $h);
164		245
165	# enforce at least this interval between updates	246	# enforce at least this interval between updates
166	our $MIN_INTERVAL = 1/100;	247	our $MIN_INTERVAL = 6/59.951;
167		248
168	{	249	{
169	package urxvt::bgdsl; # background language	250	package urxvt::bgdsl; # background language
		251
		252	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
		253	sub FR_CACHE () { 1 } # cached values
		254	sub FR_AGAIN () { 2 } # what this expr is sensitive to
		255	sub FR_STATE () { 3 } # watchers etc.
		256
		257	use List::Util qw(min max sum shuffle);
170		258
171	=head2 PROVIDERS/GENERATORS	259	=head2 PROVIDERS/GENERATORS
172		260
173	These functions provide an image, by loading it from disk, grabbing it	261	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	262	from the root screen or by simply generating it. They are used as starting
…		…
179	=item load $path	267	=item load $path
180		268
181	Loads the image at the given C<$path>. The image is set to plane tiling	269	Loads the image at the given C<$path>. The image is set to plane tiling
182	mode.	270	mode.
183		271
184	Loaded images will be cached for one cycle.	272	If the image is already in memory (e.g. because another terminal instance
		273	uses it), then the in-memory copy us returned instead.
185		274
		275	=item load_uc $path
		276
		277	Load uncached - same as load, but does not cache the image, which means it
		278	is I<always> loaded from the filesystem again.
		279
186	=cut	280	=cut
		281
		282	sub load_uc($) {
		283	$self->new_img_from_file ($path)
		284	}
187		285
188	sub load($) {	286	sub load($) {
189	my ($path) = @_;	287	my ($path) = @_;
190		288
191	$new->{load}{$path} = $old->{load}{$path} \|\| $self->new_img_from_file ($path);	289	$_IMG_CACHE{$path} \|\| do {
		290	my $img = load_uc $path;
		291	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		292	$img
		293	}
192	}	294	}
193		295
194	=item root	296	=item root
195		297
196	Returns the root window pixmap, that is, hopefully, the background image	298	Returns the root window pixmap, that is, hopefully, the background image
197	of your screen. The image is set to extend mode.	299	of your screen.
198		300
199	This function makes your expression root sensitive, that means it will be	301	This function makes your expression root sensitive, that means it will be
200	reevaluated when the bg image changes.	302	reevaluated when the bg image changes.
201		303
202	=cut	304	=cut
203		305
204	sub root() {	306	sub root() {
205	$new->{rootpmap_sensitive} = 1;	307	$frame->[FR_AGAIN]{rootpmap} = 1;
206	die "root op not supported, exg, we need you";	308	$self->new_img_from_root
207	}	309	}
208		310
209	=item solid $colour	311	=item solid $colour
210		312
211	=item solid $width, $height, $colour	313	=item solid $width, $height, $colour
212		314
213	Creates a new image and completely fills it with the given colour. The	315	Creates a new image and completely fills it with the given colour. The
214	image is set to tiling mode.	316	image is set to tiling mode.
215		317
216	If <$width> and C<$height> are omitted, it creates a 1x1 image, which is	318	If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
217	useful for solid backgrounds or for use in filtering effects.	319	useful for solid backgrounds or for use in filtering effects.
218		320
219	=cut	321	=cut
220		322
221	sub solid($$;$) {	323	sub solid($;$$) {
222	my $colour = pop;	324	my $colour = pop;
223		325
224	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	326	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
225	$img->fill ($colour);	327	$img->fill ($colour);
226	$img	328	$img
227	}	329	}
228		330
229	=back	331	=item clone $img
230		332
231	=head2 VARIABLES	333	Returns an exact copy of the image. This is useful if you want to have
		334	multiple copies of the same image to apply different effects to.
232		335
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	336	=cut
274		337
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} = $_[0];
308	}
309
310	sub counter($) {	338	sub clone($) {
311	$new->{again} = $_[0];	339	$_[0]->clone
312	$self->{counter} + 0
313	}	340	}
314		341
315	=back	342	=item merge $img ...
		343
		344	Takes any number of images and merges them together, creating a single
		345	image containing them all. The tiling mode of the first image is used as
		346	the tiling mode of the resulting image.
		347
		348	This function is called automatically when an expression returns multiple
		349	images.
		350
		351	=cut
		352
		353	sub merge(@) {
		354	return $_[0] unless $#_;
		355
		356	# rather annoyingly clumsy, but optimisation is for another time
		357
		358	my $x0 = +1e9;
		359	my $y0 = +1e9;
		360	my $x1 = -1e9;
		361	my $y1 = -1e9;
		362
		363	for (@_) {
		364	my ($x, $y, $w, $h) = $_->geometry;
		365
		366	$x0 = $x if $x0 > $x;
		367	$y0 = $y if $y0 > $y;
		368
		369	$x += $w;
		370	$y += $h;
		371
		372	$x1 = $x if $x1 < $x;
		373	$y1 = $y if $y1 < $y;
		374	}
		375
		376	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		377	$base->repeat_mode ($_[0]->repeat_mode);
		378	$base->fill ([0, 0, 0, 0]);
		379
		380	$base->draw ($_)
		381	for @_;
		382
		383	$base
		384	}
316		385
317	=head2 TILING MODES	386	=head2 TILING MODES
318		387
319	The following operators modify the tiling mode of an image, that is, the	388	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.	389	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	419	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	420	image over another image or the background colour while leaving all
352	background pixels outside the image unchanged.	421	background pixels outside the image unchanged.
353		422
354	Example: load an image and display it in the upper left corner. The rest	423	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	424	of the space is left "empty" (transparent or whatever your compositor does
356	in alpha mode, else background colour).	425	in alpha mode, else background colour).
357		426
358	pad load "mybg.png"	427	pad load "mybg.png"
359		428
360	=item extend $img	429	=item extend $img
361		430
362	Extends the image over the whole plane, using the closest pixel in the	431	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	432	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	433	filtering operations and want the pixels outside the image to have the
365	same values as the pixels near the edge.	434	same values as the pixels near the edge.
366		435
367	Example: just for curiosity, how does this pixel extension stuff work?	436	Example: just for curiosity, how does this pixel extension stuff work?
368		437
…		…
394	$img	463	$img
395	}	464	}
396		465
397	=back	466	=back
398		467
399	=head2 PIXEL OPERATORS	468	=head2 VARIABLE VALUES
400		469
401	The following operators modify the image pixels in various ways.	470	The following functions provide variable data such as the terminal window
		471	dimensions. They are not (Perl-) variables, they just return stuff that
		472	varies. Most of them make your expression sensitive to some events, for
		473	example using C<TW> (terminal width) means your expression is evaluated
		474	again when the terminal is resized.
402		475
403	=over 4	476	=over 4
404		477
405	=item clone $img	478	=item TX
406		479
407	Returns an exact copy of the image.	480	=item TY
408		481
409	=cut	482	Return the X and Y coordinates of the terminal window (the terminal
		483	window is the full window by default, and the character area only when in
		484	border-respect mode).
410		485
		486	Using these functions make your expression sensitive to window moves.
		487
		488	These functions are mainly useful to align images to the root window.
		489
		490	Example: load an image and align it so it looks as if anchored to the
		491	background (that's exactly what C<rootalign> does btw.):
		492
		493	move -TX, -TY, keep { load "mybg.png" }
		494
		495	=item TW
		496
		497	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		498	terminal window is the full window by default, and the character area only
		499	when in border-respect mode).
		500
		501	Using these functions make your expression sensitive to window resizes.
		502
		503	These functions are mainly useful to scale images, or to clip images to
		504	the window size to conserve memory.
		505
		506	Example: take the screen background, clip it to the window size, blur it a
		507	bit, align it to the window position and use it as background.
		508
		509	clip move -TX, -TY, keep { blur 5, root }
		510
		511	=cut
		512
		513	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
		514	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
		515	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
		516	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
		517
		518	=item now
		519
		520	Returns the current time as (fractional) seconds since the epoch.
		521
		522	Using this expression does I<not> make your expression sensitive to time,
		523	but the next two functions do.
		524
		525	=item again $seconds
		526
		527	When this function is used the expression will be reevaluated again in
		528	C<$seconds> seconds.
		529
		530	Example: load some image and rotate it according to the time of day (as if it were
		531	the hour pointer of a clock). Update this image every minute.
		532
		533	again 60;
		534	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
		535
		536	=item counter $seconds
		537
		538	Like C<again>, but also returns an increasing counter value, starting at
		539	0, which might be useful for some simple animation effects.
		540
		541	=cut
		542
		543	sub now() { urxvt::NOW }
		544
		545	sub again($) {
		546	$frame->[FR_AGAIN]{time} = $_[0];
		547	}
		548
411	sub clone($) {	549	sub counter($) {
412	$_[0]->clone	550	$frame->[FR_AGAIN]{time} = $_[0];
		551	$frame->[FR_STATE]{counter} + 0
413	}	552	}
		553
		554	=back
		555
		556	=head2 SHAPE CHANGING OPERATORS
		557
		558	The following operators modify the shape, size or position of the image.
		559
		560	=over 4
414		561
415	=item clip $img	562	=item clip $img
416		563
417	=item clip $width, $height, $img	564	=item clip $width, $height, $img
418		565
…		…
429	assumed.	576	assumed.
430		577
431	Example: load an image, blur it, and clip it to the window size to save	578	Example: load an image, blur it, and clip it to the window size to save
432	memory.	579	memory.
433		580
434	clip blur 10, load "mybg.png"	581	clip keep { blur 10, load "mybg.png" }
435		582
436	=cut	583	=cut
437		584
438	sub clip($;$$;$$) {	585	sub clip($;$$;$$) {
439	my $img = pop;	586	my $img = pop;
…		…
442	$img->sub_rect ($_[0], $_[1], $w, $h)	589	$img->sub_rect ($_[0], $_[1], $w, $h)
443	}	590	}
444		591
445	=item scale $img	592	=item scale $img
446		593
447	=item scale $size_percent, $img	594	=item scale $size_factor, $img
448		595
449	=item scale $width_percent, $height_percent, $img	596	=item scale $width_factor, $height_factor, $img
450		597
451	Scales the image by the given percentages in horizontal	598	Scales the image by the given factors in horizontal
452	(C<$width_percent>) and vertical (C<$height_percent>) direction.	599	(C<$width>) and vertical (C<$height>) direction.
453		600
454	If only one percentage is give, it is used for both directions.	601	If only one factor is give, it is used for both directions.
455		602
456	If no percentages are given, scales the image to the window size without	603	If no factors are given, scales the image to the window size without
457	keeping aspect.	604	keeping aspect.
458		605
459	=item resize $width, $height, $img	606	=item resize $width, $height, $img
460		607
461	Resizes the image to exactly C<$width> times C<$height> pixels.	608	Resizes the image to exactly C<$width> times C<$height> pixels.
462		609
463	=cut	610	=item fit $img
464		611
465	#TODO: maximise, maximise_fill?	612	=item fit $width, $height, $img
		613
		614	Fits the image into the given C<$width> and C<$height> without changing
		615	aspect, or the terminal size. That means it will be shrunk or grown until
		616	the whole image fits into the given area, possibly leaving borders.
		617
		618	=item cover $img
		619
		620	=item cover $width, $height, $img
		621
		622	Similar to C<fit>, but shrinks or grows until all of the area is covered
		623	by the image, so instead of potentially leaving borders, it will cut off
		624	image data that doesn't fit.
		625
		626	=cut
466		627
467	sub scale($;$;$) {	628	sub scale($;$;$) {
468	my $img = pop;	629	my $img = pop;
469		630
470	@_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01)	631	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
471	: @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01)	632	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
472	: $img->scale (TW, TH)	633	: $img->scale (TW, TH)
473	}	634	}
474		635
475	sub resize($$$) {	636	sub resize($$$) {
476	my $img = pop;	637	my $img = pop;
477	$img->scale ($_[0], $_[1])	638	$img->scale ($_[0], $_[1])
478	}	639	}
479		640
		641	sub fit($;$$) {
		642	my $img = pop;
		643	my $w = ($_[0] \|\| TW) / $img->w;
		644	my $h = ($_[1] \|\| TH) / $img->h;
		645	scale +(min $w, $h), $img
		646	}
		647
		648	sub cover($;$$) {
		649	my $img = pop;
		650	my $w = ($_[0] \|\| TW) / $img->w;
		651	my $h = ($_[1] \|\| TH) / $img->h;
		652	scale +(max $w, $h), $img
		653	}
		654
480	=item move $dx, $dy, $img	655	=item move $dx, $dy, $img
481		656
482	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in	657	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
483	the vertical.	658	the vertical.
484		659
485	Example: move the image right by 20 pixels and down by 30.	660	Example: move the image right by 20 pixels and down by 30.
486		661
487	move 20, 30, ...	662	move 20, 30, ...
		663
		664	=item align $xalign, $yalign, $img
		665
		666	Aligns the image according to a factor - C<0> means the image is moved to
		667	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		668	exactly centered and C<1> means it touches the right or bottom edge.
		669
		670	Example: remove any visible border around an image, center it vertically but move
		671	it to the right hand side.
		672
		673	align 1, 0.5, pad $img
		674
		675	=item center $img
		676
		677	=item center $width, $height, $img
		678
		679	Centers the image, i.e. the center of the image is moved to the center of
		680	the terminal window (or the box specified by C<$width> and C<$height> if
		681	given).
		682
		683	Example: load an image and center it.
		684
		685	center keep { pad load "mybg.png" }
488		686
489	=item rootalign $img	687	=item rootalign $img
490		688
491	Moves the image so that it appears glued to the screen as opposed to the	689	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	690	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	691	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
494	top left of the screen.	692	top left of the screen.
495		693
496	Example: load a background image, put it in mirror mode and root align it.	694	Example: load a background image, put it in mirror mode and root align it.
497		695
498	rootalign mirror load "mybg.png"	696	rootalign keep { mirror load "mybg.png" }
499		697
500	Example: take the screen background and align it, giving the illusion of	698	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.	699	transparency as long as the window isn't in front of other windows.
502		700
503	rootalign root	701	rootalign root
504		702
505	=cut	703	=cut
506		704
507	sub move($$;$) {	705	sub move($$;$) {
508	my $img = pop->clone;	706	my $img = pop->clone;
509	$img->move ($_[0], $_[1]);	707	$img->move ($_[0], $_[1]);
510	$img	708	$img
511	}	709	}
512		710
		711	sub align($;$$) {
		712	my $img = pop;
		713
		714	move $_[0] * (TW - $img->w),
		715	$_[1] * (TH - $img->h),
		716	$img
		717	}
		718
		719	sub center($;$$) {
		720	my $img = pop;
		721	my $w = $_[0] \|\| TW;
		722	my $h = $_[1] \|\| TH;
		723
		724	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		725	}
		726
513	sub rootalign($) {	727	sub rootalign($) {
514	move -TX, -TY, $_[0]	728	move -TX, -TY, $_[0]
515	}	729	}
516		730
		731	=item rotate $center_x, $center_y, $degrees, $img
		732
		733	Rotates the image clockwise by C<$degrees> degrees, around the point at
		734	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		735
		736	Example: rotate the image by 90 degrees around it's center.
		737
		738	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		739
		740	=cut
		741
		742	sub rotate($$$$) {
		743	my $img = pop;
		744	$img->rotate (
		745	$_[0] * ($img->w + $img->x),
		746	$_[1] * ($img->h + $img->y),
		747	$_[2] * (3.14159265 / 180),
		748	)
		749	}
		750
		751	=back
		752
		753	=head2 COLOUR MODIFICATIONS
		754
		755	The following operators change the pixels of the image.
		756
		757	=over 4
		758
517	=item contrast $factor, $img	759	=item contrast $factor, $img
518		760
519	=item contrast $r, $g, $b, $img	761	=item contrast $r, $g, $b, $img
520		762
521	=item contrast $r, $g, $b, $a, $img	763	=item contrast $r, $g, $b, $a, $img
522		764
523	Adjusts the I<contrast> of an image.	765	Adjusts the I<contrast> of an image.
524		766
525	#TODO#	767	The first form applies a single C<$factor> to red, green and blue, the
		768	second form applies separate factors to each colour channel, and the last
		769	form includes the alpha channel.
526		770
		771	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		772	contrast.
		773
		774	Due to limitations in the underlying XRender extension, lowering contrast
		775	also reduces brightness, while increasing contrast currently also
		776	increases brightness.
		777
527	=item brightness $factor, $img	778	=item brightness $bias, $img
528		779
529	=item brightness $r, $g, $b, $img	780	=item brightness $r, $g, $b, $img
530		781
531	=item brightness $r, $g, $b, $a, $img	782	=item brightness $r, $g, $b, $a, $img
532		783
533	Adjusts the brightness of an image.	784	Adjusts the brightness of an image.
		785
		786	The first form applies a single C<$bias> to red, green and blue, the
		787	second form applies separate biases to each colour channel, and the last
		788	form includes the alpha channel.
		789
		790	Values less than 0 reduce brightness, while values larger than 0 increase
		791	it. Useful range is from -1 to 1 - the former results in a black, the
		792	latter in a white picture.
		793
		794	Due to idiosyncrasies in the underlying XRender extension, biases less
		795	than zero can be I<very> slow.
534		796
535	=cut	797	=cut
536		798
537	sub contrast($$;$$;$) {	799	sub contrast($$;$$;$) {
538	my $img = pop;	800	my $img = pop;
539	my ($r, $g, $b, $a) = @_;	801	my ($r, $g, $b, $a) = @_;
540		802
541	($g, $b) = ($r, $r) if @_ < 4;	803	($g, $b) = ($r, $r) if @_ < 3;
542	$a = 1 if @_ < 5;	804	$a = 1 if @_ < 4;
543		805
544	$img = $img->clone;	806	$img = $img->clone;
545	$img->contrast ($r, $g, $b, $a);	807	$img->contrast ($r, $g, $b, $a);
546	$img	808	$img
547	}	809	}
548		810
549	sub brightness($$;$$;$) {	811	sub brightness($$;$$;$) {
550	my $img = pop;	812	my $img = pop;
551	my ($r, $g, $b, $a) = @_;	813	my ($r, $g, $b, $a) = @_;
552		814
553	($g, $b) = ($r, $r) if @_ < 4;	815	($g, $b) = ($r, $r) if @_ < 3;
554	$a = 1 if @_ < 5;	816	$a = 1 if @_ < 4;
555		817
556	$img = $img->clone;	818	$img = $img->clone;
557	$img->brightness ($r, $g, $b, $a);	819	$img->brightness ($r, $g, $b, $a);
558	$img	820	$img
559	}	821	}
…		…
563	=item blur $radius_horz, $radius_vert, $img	825	=item blur $radius_horz, $radius_vert, $img
564		826
565	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii	827	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
566	can also be specified separately.	828	can also be specified separately.
567		829
		830	Blurring is often I<very> slow, at least compared or other
		831	operators. Larger blur radii are slower than smaller ones, too, so if you
		832	don't want to freeze your screen for long times, start experimenting with
		833	low values for radius (<5).
		834
568	=cut	835	=cut
569		836
570	sub blur($$;$) {	837	sub blur($$;$) {
571	my $img = pop;	838	my $img = pop;
572	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	839	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
573	}	840	}
574		841
575	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
576
577	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
578	pointer at C<$center_x> and C<$center_y> (specified as percentage of image
579	width/height), generating a new image with width C<$new_width> and height
580	C<$new_height>.
581
582	#TODO# new width, height, maybe more operators?
583
584	Example: rotate the image by 90 degrees
585
586	=cut
587
588	sub rotate($$$$$$) {
589	my $img = pop;
590	$img->rotate (
591	$_[0],
592	$_[1],
593	$_[2] * $img->w * .01,
594	$_[3] * $img->h * .01,
595	$_[4] * (3.14159265 / 180),
596	)
597	}
598
599	=back	842	=back
600		843
		844	=head2 OTHER STUFF
		845
		846	Anything that didn't fit any of the other categories, even after applying
		847	force and closing our eyes.
		848
		849	=over 4
		850
		851	=item keep { ... }
		852
		853	This operator takes a code block as argument, that is, one or more
		854	statements enclosed by braces.
		855
		856	The trick is that this code block is only evaluated when the outcome
		857	changes - on other calls the C<keep> simply returns the image it computed
		858	previously (yes, it should only be used with images). Or in other words,
		859	C<keep> I<caches> the result of the code block so it doesn't need to be
		860	computed again.
		861
		862	This can be extremely useful to avoid redoing slow operations - for
		863	example, if your background expression takes the root background, blurs it
		864	and then root-aligns it it would have to blur the root background on every
		865	window move or resize.
		866
		867	Another example is C<load>, which can be quite slow.
		868
		869	In fact, urxvt itself encloses the whole expression in some kind of
		870	C<keep> block so it only is reevaluated as required.
		871
		872	Putting the blur into a C<keep> block will make sure the blur is only done
		873	once, while the C<rootalign> is still done each time the window moves.
		874
		875	rootlign keep { blur 10, root }
		876
		877	This leaves the question of how to force reevaluation of the block,
		878	in case the root background changes: If expression inside the block
		879	is sensitive to some event (root background changes, window geometry
		880	changes), then it will be reevaluated automatically as needed.
		881
		882	=cut
		883
		884	sub keep(&) {
		885	my $id = $_[0]+0;
		886
		887	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		888
		889	unless ($frame->[FR_CACHE]) {
		890	$frame->[FR_CACHE] = [ $_[0]() ];
		891
		892	my $self = $self;
		893	my $frame = $frame;
		894	Scalar::Util::weaken $frame;
		895	$self->compile_frame ($frame, sub {
		896	# clear this frame cache, also for all parents
		897	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		898	undef $frame->[FR_CACHE];
		899	}
		900
		901	$self->recalculate;
		902	});
		903	};
		904
		905	# in scalar context we always return the first original result, which
		906	# is not quite how perl works.
		907	wantarray
		908	? @{ $frame->[FR_CACHE] }
		909	: $frame->[FR_CACHE][0]
		910	}
		911
		912	# sub keep_clear() {
		913	# delete $self->{frame_cache};
		914	# }
		915
		916	=back
		917
601	=cut	918	=cut
602		919
603	}	920	}
604		921
605	sub parse_expr {	922	sub parse_expr {
606	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	923	my $expr = eval
		924	"sub {\n"
		925	. "package urxvt::bgdsl;\n"
		926	. "#line 0 'background expression'\n"
		927	. "$_[0]\n"
		928	. "}";
607	die if $@;	929	die if $@;
608	$expr	930	$expr
609	}	931	}
610		932
611	# compiles a parsed expression	933	# compiles a parsed expression
612	sub set_expr {	934	sub set_expr {
613	my ($self, $expr) = @_;	935	my ($self, $expr) = @_;
614		936
		937	$self->{root} = [];
615	$self->{expr} = $expr;	938	$self->{expr} = $expr;
616	$self->recalculate;	939	$self->recalculate;
		940	}
		941
		942	# takes a hash of sensitivity indicators and installs watchers
		943	sub compile_frame {
		944	my ($self, $frame, $cb) = @_;
		945
		946	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		947	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		948
		949	# don't keep stuff alive
		950	Scalar::Util::weaken $state;
		951
		952	if ($again->{nested}) {
		953	$state->{nested} = 1;
		954	} else {
		955	delete $state->{nested};
		956	}
		957
		958	if (my $interval = $again->{time}) {
		959	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		960	if $state->{time}[0] != $interval;
		961
		962	# callback might have changed, although we could just rule that out
		963	$state->{time}[1]->cb (sub {
		964	++$state->{counter};
		965	$cb->();
		966	});
		967	} else {
		968	delete $state->{time};
		969	}
		970
		971	if ($again->{position}) {
		972	$state->{position} = $self->on (position_change => $cb);
		973	} else {
		974	delete $state->{position};
		975	}
		976
		977	if ($again->{size}) {
		978	$state->{size} = $self->on (size_change => $cb);
		979	} else {
		980	delete $state->{size};
		981	}
		982
		983	if ($again->{rootpmap}) {
		984	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		985	} else {
		986	delete $state->{rootpmap};
		987	}
617	}	988	}
618		989
619	# evaluate the current bg expression	990	# evaluate the current bg expression
620	sub recalculate {	991	sub recalculate {
621	my ($arg_self) = @_;	992	my ($arg_self) = @_;
…		…
631		1002
632	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1003	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
633		1004
634	# set environment to evaluate user expression	1005	# set environment to evaluate user expression
635		1006
636	local $self = $arg_self;	1007	local $self = $arg_self;
637
638	local $HOME = $ENV{HOME};	1008	local $HOME = $ENV{HOME};
639	local $old = $self->{state};	1009	local $frame = [];
640	local $new = my $state = $self->{state} = {};
641		1010
642	($x, $y, $w, $h) =
643	$self->background_geometry ($self->{border});	1011	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
644		1012
645	# evaluate user expression	1013	# evaluate user expression
646		1014
647	my $img = eval { $self->{expr}->() };	1015	my @img = eval { $self->{expr}->() };
648	warn $@ if $@;#d#	1016	die $@ if $@;
		1017	die "background-expr did not return anything.\n" unless @img;
		1018	die "background-expr: expected image(s), got something else.\n"
649	die if !UNIVERSAL::isa $img, "urxvt::img";	1019	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
650		1020
651	$state->{size_sensitive} = 1	1021	my $img = urxvt::bgdsl::merge @img;
		1022
		1023	$frame->[FR_AGAIN]{size} = 1
652	if $img->repeat_mode != urxvt::RepeatNormal;	1024	if $img->repeat_mode != urxvt::RepeatNormal;
653		1025
654	# if the expression is sensitive to external events, prepare reevaluation then	1026	# if the expression is sensitive to external events, prepare reevaluation then
655		1027	$self->compile_frame ($frame, sub { $arg_self->recalculate });
656	my $repeat;
657
658	if (my $again = $state->{again}) {
659	$repeat = 1;
660	my $self = $self;
661	$state->{timer} = $again == $old->{again}
662	? $old->{timer}
663	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
664	++$self->{counter};
665	$self->recalculate
666	});
667	}
668
669	if (delete $state->{position_sensitive}) {
670	$repeat = 1;
671	$self->enable (position_change => sub { $_[0]->recalculate });
672	} else {
673	$self->disable ("position_change");
674	}
675
676	if (delete $state->{size_sensitive}) {
677	$repeat = 1;
678	$self->enable (size_change => sub { $_[0]->recalculate });
679	} else {
680	$self->disable ("size_change");
681	}
682
683	if (delete $state->{rootpmap_sensitive}) {
684	$repeat = 1;
685	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
686	} else {
687	$self->disable ("rootpmap_change");
688	}
689		1028
690	# clear stuff we no longer need	1029	# clear stuff we no longer need
691		1030
692	%$old = ();	1031	# unless (%{ $frame->[FR_STATE] }) {
693
694	unless ($repeat) {
695	delete $self->{state};	1032	# delete $self->{state};
696	delete $self->{expr};	1033	# delete $self->{expr};
697	}	1034	# }
698		1035
699	# set background pixmap	1036	# set background pixmap
700		1037
701	$self->set_background ($img, $self->{border});	1038	$self->set_background ($img, $self->{border});
702	$self->scr_recolour (0);	1039	$self->scr_recolour (0);
…		…
704	}	1041	}
705		1042
706	sub on_start {	1043	sub on_start {
707	my ($self) = @_;	1044	my ($self) = @_;
708		1045
709	my $expr = $self->x_resource ("background.expr")	1046	my $expr = $self->x_resource ("%.expr")
710	or return;	1047	or return;
711		1048
		1049	$self->has_render
		1050	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1051
712	$self->set_expr (parse_expr $expr);	1052	$self->set_expr (parse_expr $expr);
713	$self->{border} = $self->x_resource_boolean ("background.border");	1053	$self->{border} = $self->x_resource_boolean ("%.border");
		1054
		1055	$MIN_INTERVAL = $self->x_resource ("%.interval");
714		1056
715	()	1057	()
716	}	1058	}
717		1059

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.38 by root, Fri Jun 8 21:48:07 2012 UTC vs. Revision 1.68 by root, Sun Jul 1 21:47:07 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.38 by root, Fri Jun 8 21:48:07 2012 UTC vs.
Revision 1.68 by root, Sun Jul 1 21:47:07 2012 UTC