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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.41 by root, Fri Jun 8 22:21:48 2012 UTC vs.
Revision 1.65 by sf-exg, Wed Jun 20 18:18:14 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		5	#:META:X_RESOURCE:%.interval:seconds:minimum time between updates
6	#TODO: once, rootalign
7		6
8	=head1 NAME	7	=head1 NAME
9		8
10	background - manage terminal background	9	background - manage terminal background
11		10
12	=head1 SYNOPSIS	11	=head1 SYNOPSIS
13		12
14	urxvt --background-expr 'background expression'	13	urxvt --background-expr 'background expression'
15	--background-border	14	--background-border
		15	--background-interval seconds
16		16
17	=head1 DESCRIPTION	17	=head1 DESCRIPTION
18		18
19	This extension manages the terminal background by creating a picture that	19	This extension manages the terminal background by creating a picture that
20	is behind the text, replacing the normal background colour.	20	is behind the text, replacing the normal background colour.
26	to be as simple as possible.	26	to be as simple as possible.
27		27
28	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
29	use:	29	use:
30		30
31	urxvt --background-expr 'scale load "/path/to/mybg.png"'	31	urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
32		32
33	Or specified as a X resource:	33	Or specified as a X resource:
34		34
35	URxvt.background-expr: scale load "/path/to/mybg.png"	35	URxvt.background-expr: scale keep { load "/path/to/mybg.png" }
36		36
37	=head1 THEORY OF OPERATION	37	=head1 THEORY OF OPERATION
38		38
39	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
40	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
…		…
53	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
54	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
55	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
56	timer elapses), then the expression will be evaluated again.	56	timer elapses), then the expression will be evaluated again.
57		57
58	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"
59	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
60	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
61	example. That ensures that the picture always fills the terminal, even	61	example. That ensures that the picture always fills the terminal, even
62	after it's size changes.	62	after its size changes.
63		63
64	=head2 EXPRESSIONS	64	=head2 EXPRESSIONS
65		65
66	Expressions are normal Perl expressions, in fact, they are Perl blocks -	66	Expressions are normal Perl expressions, in fact, they are Perl blocks -
67	which means you could use multiple lines and statements:	67	which means you could use multiple lines and statements:
68		68
		69	scale keep {
69	again 3600;	70	again 3600;
70	if (localtime now)[6]) {	71	if (localtime now)[6]) {
71	return scale load "$HOME/weekday.png";	72	return load "$HOME/weekday.png";
72	} else {	73	} else {
73	return scale load "$HOME/sunday.png";	74	return load "$HOME/sunday.png";
		75	}
74	}	76	}
75		77
76	This expression gets evaluated once per hour. It will set F<sunday.png> as	78	This expression is evaluated once per hour. It will set F<sunday.png> as
77	background on Sundays, and F<weekday.png> on all other days.	79	background on Sundays, and F<weekday.png> on all other days.
78		80
79	Fortunately, we expect that most expressions will be much simpler, with	81	Fortunately, we expect that most expressions will be much simpler, with
80	little Perl knowledge needed.	82	little Perl knowledge needed.
81		83
…		…
99	its result becomes the argument to the C<scale> function.	101	its result becomes the argument to the C<scale> function.
100		102
101	Many operators also allow some parameters preceding the input image	103	Many operators also allow some parameters preceding the input image
102	that modify its behaviour. For example, C<scale> without any additional	104	that modify its behaviour. For example, C<scale> without any additional
103	arguments scales the image to size of the terminal window. If you specify	105	arguments scales the image to size of the terminal window. If you specify
104	an additional argument, it uses it as a percentage:	106	an additional argument, it uses it as a scale factor (multiply by 100 to
		107	get a percentage):
105		108
106	scale 200, load "$HOME/mypic.png"	109	scale 2, load "$HOME/mypic.png"
107		110
108	This enlarges the image by a factor of 2 (200%). As you can see, C<scale>	111	This enlarges the image by a factor of 2 (200%). As you can see, C<scale>
109	has now two arguments, the C<200> and the C<load> expression, while	112	has now two arguments, the C<200> and the C<load> expression, while
110	C<load> only has one argument. Arguments are separated from each other by	113	C<load> only has one argument. Arguments are separated from each other by
111	commas.	114	commas.
112		115
113	Scale also accepts two arguments, which are then separate factors for both	116	Scale also accepts two arguments, which are then separate factors for both
114	horizontal and vertical dimensions. For example, this halves the image	117	horizontal and vertical dimensions. For example, this halves the image
115	width and doubles the image height:	118	width and doubles the image height:
116		119
117	scale 50, 200, load "$HOME/mypic.png"	120	scale 0.5, 2, load "$HOME/mypic.png"
118		121
119	Other effects than scalign are also readily available, for exmaple, you can	122	IF you try out these expressions, you might suffer from sluggishness,
120	tile the image to fill the whole window, instead of resizing it:	123	because each time the terminal is resized, it again loads the PNG image
		124	and scales it. Scaling is usually fast, but loading the image can be quite
		125	time consuming. This is where C<keep> comes in handy:
121		126
		127	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		128
		129	The C<keep> operator executes all the statements inside the braces only
		130	once, or when it thinks the outcome might change. In other cases it
		131	returns the last value computed by the brace block.
		132
		133	This means that the C<load> is only executed once, which makes it much
		134	faster, but also means that more memory is being used, because the loaded
		135	image must be kept in memory at all times. In this expression, the
		136	trade-off is likely worth it.
		137
		138	But back to effects: Other effects than scaling are also readily
		139	available, for example, you can tile the image to fill the whole window,
		140	instead of resizing it:
		141
122	tile load "$HOME/mypic.png"	142	tile keep { load "$HOME/mypic.png" }
123		143
124	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator	144	In fact, images returned by C<load> are in C<tile> mode by default, so the
125	is kind of superfluous.	145	C<tile> operator is kind of superfluous.
126		146
127	Another common effect is to mirror the image, so that the same edges touch:	147	Another common effect is to mirror the image, so that the same edges
		148	touch:
128		149
129	mirror load "$HOME/mypic.png"	150	mirror keep { load "$HOME/mypic.png" }
130		151
131	This is also a typical background expression:	152	Another common background expression is:
132		153
133	rootalign root	154	rootalign root
134		155
135	It first takes a snapshot of the screen background image, and then	156	This one first takes a snapshot of the screen background image, and then
136	moves it to the upper left corner of the screen - the result is	157	moves it to the upper left corner of the screen (as opposed to the upper
137	pseudo-transparency, as the image seems to be static while the window is	158	left corner of the terminal window)- the result is pseudo-transparency:
138	moved around.	159	the image seems to be static while the window is moved around.
139		160
140	=head2 CYCLES AND CACHING	161	=head2 CACHING AND SENSITIVITY
141		162
142	As has been mentioned before, the expression might be evaluated multiple	163	Since some operations (such as C<load> and C<blur>) can take a long time,
143	times. Each time the expression is reevaluated, a new cycle is said to	164	caching results can be very important for a smooth operation. Caching can
144	have begun. Many operators cache their results till the next cycle.	165	also be useful to reduce memory usage, though, for example, when an image
		166	is cached by C<load>, it could be shared by multiple terminal windows
		167	running inside urxvtd.
145		168
146	For example, the C<load> operator keeps a copy of the image. If it is	169	=head3 C<keep { ... }> caching
147	asked to load the same image on the next cycle it will not load it again,
148	but return the cached copy.
149		170
150	This only works for one cycle though, so as long as you load the same	171	The most important way to cache expensive operations is to use C<keep {
151	image every time, it will always be cached, but when you load a different	172	... }>. The C<keep> operator takes a block of multiple statements enclosed
152	image, it will forget about the first one.	173	by C<{}> and keeps the return value in memory.
153		174
154	This allows you to either speed things up by keeping multiple images in	175	An expression can be "sensitive" to various external events, such as
155	memory, or comserve memory by loading images more often.	176	scaling or moving the window, root background changes and timers. Simply
		177	using an expression (such as C<scale> without parameters) that depend on
		178	certain changing values (called "variables"), or using those variables
		179	directly, will make an expression sensitive to these events - for example,
		180	using C<scale> or C<TW> will make the expression sensitive to the terminal
		181	size, and thus to resizing events.
156		182
157	For example, you can keep two images in memory and use a random one like	183	When such an event happens, C<keep> will automatically trigger a
158	this:	184	reevaluation of the whole expression with the new value of the expression.
159		185
160	my $img1 = load "img1.png";	186	C<keep> is most useful for expensive operations, such as C<blur>:
161	my $img2 = load "img2.png";
162	(0.5 > rand) ? $img1 : $img2
163		187
164	Since both images are "loaded" every time the expression is evaluated,	188	rootalign once { blur 20, root }
165	they are always kept in memory. Contrast this version:
166		189
167	my $path1 = "img1.png";	190	This makes a blurred copy of the root background once, and on subsequent
168	my $path2 = "img2.png";	191	calls, just root-aligns it. Since C<blur> is usually quite slow and
169	load ((0.5 > rand) ? $path1 : $path2)	192	C<rootalign> is quite fast, this trades extra memory (for the cached
		193	blurred pixmap) with speed (blur only needs to be redone when root
		194	changes).
170		195
171	Here, a path is selected randomly, and load is only called for one image,	196	=head3 C<load> caching
172	so keeps only one image in memory. If, on the next evaluation, luck	197
173	decides to use the other path, then it will have to load that image again.	198	The C<load> operator itself does not keep images in memory, but as long as
		199	the image is still in memory, C<load> will use the in-memory image instead
		200	of loading it freshly from disk.
		201
		202	That means that this expression:
		203
		204	keep { load "$HOME/path..." }
		205
		206	Not only caches the image in memory, other terminal instances that try to
		207	C<load> it can reuse that in-memory copy.
174		208
175	=head1 REFERENCE	209	=head1 REFERENCE
176		210
177	=head2 COMMAND LINE SWITCHES	211	=head2 COMMAND LINE SWITCHES
178		212
…		…
188	overwriting borders and any other areas, such as the scrollbar.	222	overwriting borders and any other areas, such as the scrollbar.
189		223
190	Specifying this flag changes the behaviour, so that the image only	224	Specifying this flag changes the behaviour, so that the image only
191	replaces the background of the character area.	225	replaces the background of the character area.
192		226
		227	=item --background-interval seconds
		228
		229	Since some operations in the underlying XRender extension can effectively
		230	freeze your X-server for prolonged time, this extension enforces a minimum
		231	time between updates, which is normally about 0.1 seconds.
		232
		233	If you want to do updates more often, you can decrease this safety
		234	interval with this switch.
		235
193	=back	236	=back
194		237
195	=cut	238	=cut
196		239
		240	our %_IMG_CACHE;
197	our $HOME;	241	our $HOME;
198	our ($self, $old, $new);	242	our ($self, $frame);
199	our ($x, $y, $w, $h);	243	our ($x, $y, $w, $h);
200		244
201	# enforce at least this interval between updates	245	# enforce at least this interval between updates
202	our $MIN_INTERVAL = 1/100;	246	our $MIN_INTERVAL = 6/59.951;
203		247
204	{	248	{
205	package urxvt::bgdsl; # background language	249	package urxvt::bgdsl; # background language
		250
		251	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
		252	sub FR_CACHE () { 1 } # cached values
		253	sub FR_AGAIN () { 2 } # what this expr is sensitive to
		254	sub FR_STATE () { 3 } # watchers etc.
		255
		256	use List::Util qw(min max sum shuffle);
206		257
207	=head2 PROVIDERS/GENERATORS	258	=head2 PROVIDERS/GENERATORS
208		259
209	These functions provide an image, by loading it from disk, grabbing it	260	These functions provide an image, by loading it from disk, grabbing it
210	from the root screen or by simply generating it. They are used as starting	261	from the root screen or by simply generating it. They are used as starting
…		…
215	=item load $path	266	=item load $path
216		267
217	Loads the image at the given C<$path>. The image is set to plane tiling	268	Loads the image at the given C<$path>. The image is set to plane tiling
218	mode.	269	mode.
219		270
220	Loaded images will be cached for one cycle.	271	If the image is already in memory (e.g. because another terminal instance
		272	uses it), then the in-memory copy us returned instead.
221		273
		274	=item load_uc $path
		275
		276	Load uncached - same as load, but does not cache the image, which means it
		277	is I<always> loaded from the filesystem again.
		278
222	=cut	279	=cut
		280
		281	sub load_uc($) {
		282	$self->new_img_from_file ($path)
		283	}
223		284
224	sub load($) {	285	sub load($) {
225	my ($path) = @_;	286	my ($path) = @_;
226		287
227	$new->{load}{$path} = $old->{load}{$path} \|\| $self->new_img_from_file ($path);	288	$_IMG_CACHE{$path} \|\| do {
		289	my $img = load_uc $path;
		290	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		291	$img
		292	}
228	}	293	}
229		294
230	=item root	295	=item root
231		296
232	Returns the root window pixmap, that is, hopefully, the background image	297	Returns the root window pixmap, that is, hopefully, the background image
233	of your screen. The image is set to extend mode.	298	of your screen.
234		299
235	This function makes your expression root sensitive, that means it will be	300	This function makes your expression root sensitive, that means it will be
236	reevaluated when the bg image changes.	301	reevaluated when the bg image changes.
237		302
238	=cut	303	=cut
239		304
240	sub root() {	305	sub root() {
241	$new->{rootpmap_sensitive} = 1;	306	$frame->[FR_AGAIN]{rootpmap} = 1;
242	die "root op not supported, exg, we need you";	307	$self->new_img_from_root
243	}	308	}
244		309
245	=item solid $colour	310	=item solid $colour
246		311
247	=item solid $width, $height, $colour	312	=item solid $width, $height, $colour
…		…
252	If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is	317	If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
253	useful for solid backgrounds or for use in filtering effects.	318	useful for solid backgrounds or for use in filtering effects.
254		319
255	=cut	320	=cut
256		321
257	sub solid($$;$) {	322	sub solid($;$$) {
258	my $colour = pop;	323	my $colour = pop;
259		324
260	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	325	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
261	$img->fill ($colour);	326	$img->fill ($colour);
262	$img	327	$img
263	}	328	}
264		329
265	=back	330	=item clone $img
266		331
267	=head2 VARIABLES	332	Returns an exact copy of the image. This is useful if you want to have
		333	multiple copies of the same image to apply different effects to.
268		334
269	The following functions provide variable data such as the terminal window
270	dimensions. They are not (Perl-) variables, they jsut return stuff that
271	varies. Most of them make your expression sensitive to some events, for
272	example using C<TW> (terminal width) means your expression is evaluated
273	again when the terminal is resized.
274
275	=over 4
276
277	=item TX
278
279	=item TY
280
281	Return the X and Y coordinates of the terminal window (the terminal
282	window is the full window by default, and the character area only when in
283	border-respect mode).
284
285	Using these functions make your expression sensitive to window moves.
286
287	These functions are mainly useful to align images to the root window.
288
289	Example: load an image and align it so it looks as if anchored to the
290	background.
291
292	move -TX, -TY, load "mybg.png"
293
294	=item TW
295
296	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
297	terminal window is the full window by default, and the character area only
298	when in border-respect mode).
299
300	Using these functions make your expression sensitive to window resizes.
301
302	These functions are mainly useful to scale images, or to clip images to
303	the window size to conserve memory.
304
305	Example: take the screen background, clip it to the window size, blur it a
306	bit, align it to the window position and use it as background.
307
308	clip move -TX, -TY, blur 5, root
309
310	=cut	335	=cut
311		336
312	sub TX() { $new->{position_sensitive} = 1; $x }
313	sub TY() { $new->{position_sensitive} = 1; $y }
314	sub TW() { $new->{size_sensitive} = 1; $w }
315	sub TH() { $new->{size_sensitive} = 1; $h }
316
317	=item now
318
319	Returns the current time as (fractional) seconds since the epoch.
320
321	Using this expression does I<not> make your expression sensitive to time,
322	but the next two functions do.
323
324	=item again $seconds
325
326	When this function is used the expression will be reevaluated again in
327	C<$seconds> seconds.
328
329	Example: load some image and rotate it according to the time of day (as if it were
330	the hour pointer of a clock). Update this image every minute.
331
332	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
333
334	=item counter $seconds
335
336	Like C<again>, but also returns an increasing counter value, starting at
337	0, which might be useful for some simple animation effects.
338
339	=cut
340
341	sub now() { urxvt::NOW }
342
343	sub again($) {
344	$new->{again} = $_[0];
345	}
346
347	sub counter($) {	337	sub clone($) {
348	$new->{again} = $_[0];	338	$_[0]->clone
349	$self->{counter} + 0
350	}	339	}
351		340
352	=back	341	=item merge $img ...
		342
		343	Takes any number of images and merges them together, creating a single
		344	image containing them all. The tiling mode of the first image is used as
		345	the tiling mode of the resulting image.
		346
		347	This function is called automatically when an expression returns multiple
		348	images.
		349
		350	=cut
		351
		352	sub merge(@) {
		353	return $_[0] unless $#_;
		354
		355	# rather annoyingly clumsy, but optimisation is for another time
		356
		357	my $x0 = +1e9;
		358	my $y0 = +1e9;
		359	my $x1 = -1e9;
		360	my $y1 = -1e9;
		361
		362	for (@_) {
		363	my ($x, $y, $w, $h) = $_->geometry;
		364
		365	$x0 = $x if $x0 > $x;
		366	$y0 = $y if $y0 > $y;
		367
		368	$x += $w;
		369	$y += $h;
		370
		371	$x1 = $x if $x1 < $x;
		372	$y1 = $y if $y1 < $y;
		373	}
		374
		375	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		376	$base->repeat_mode ($_[0]->repeat_mode);
		377	$base->fill ([0, 0, 0, 0]);
		378
		379	$base->draw ($_)
		380	for @_;
		381
		382	$base
		383	}
353		384
354	=head2 TILING MODES	385	=head2 TILING MODES
355		386
356	The following operators modify the tiling mode of an image, that is, the	387	The following operators modify the tiling mode of an image, that is, the
357	way that pixels outside the image area are painted when the image is used.	388	way that pixels outside the image area are painted when the image is used.
…		…
387	become transparent. This mode is most useful when you want to place an	418	become transparent. This mode is most useful when you want to place an
388	image over another image or the background colour while leaving all	419	image over another image or the background colour while leaving all
389	background pixels outside the image unchanged.	420	background pixels outside the image unchanged.
390		421
391	Example: load an image and display it in the upper left corner. The rest	422	Example: load an image and display it in the upper left corner. The rest
392	of the space is left "empty" (transparent or wahtever your compisotr does	423	of the space is left "empty" (transparent or whatever your compositor does
393	in alpha mode, else background colour).	424	in alpha mode, else background colour).
394		425
395	pad load "mybg.png"	426	pad load "mybg.png"
396		427
397	=item extend $img	428	=item extend $img
398		429
399	Extends the image over the whole plane, using the closest pixel in the	430	Extends the image over the whole plane, using the closest pixel in the
400	area outside the image. This mode is mostly useful when you more complex	431	area outside the image. This mode is mostly useful when you use more complex
401	filtering operations and want the pixels outside the image to have the	432	filtering operations and want the pixels outside the image to have the
402	same values as the pixels near the edge.	433	same values as the pixels near the edge.
403		434
404	Example: just for curiosity, how does this pixel extension stuff work?	435	Example: just for curiosity, how does this pixel extension stuff work?
405		436
…		…
431	$img	462	$img
432	}	463	}
433		464
434	=back	465	=back
435		466
436	=head2 PIXEL OPERATORS	467	=head2 VARIABLE VALUES
437		468
438	The following operators modify the image pixels in various ways.	469	The following functions provide variable data such as the terminal window
		470	dimensions. They are not (Perl-) variables, they just return stuff that
		471	varies. Most of them make your expression sensitive to some events, for
		472	example using C<TW> (terminal width) means your expression is evaluated
		473	again when the terminal is resized.
439		474
440	=over 4	475	=over 4
441		476
442	=item clone $img	477	=item TX
443		478
444	Returns an exact copy of the image.	479	=item TY
445		480
446	=cut	481	Return the X and Y coordinates of the terminal window (the terminal
		482	window is the full window by default, and the character area only when in
		483	border-respect mode).
447		484
		485	Using these functions make your expression sensitive to window moves.
		486
		487	These functions are mainly useful to align images to the root window.
		488
		489	Example: load an image and align it so it looks as if anchored to the
		490	background (that's exactly what C<rootalign> does btw.):
		491
		492	move -TX, -TY, keep { load "mybg.png" }
		493
		494	=item TW
		495
		496	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		497	terminal window is the full window by default, and the character area only
		498	when in border-respect mode).
		499
		500	Using these functions make your expression sensitive to window resizes.
		501
		502	These functions are mainly useful to scale images, or to clip images to
		503	the window size to conserve memory.
		504
		505	Example: take the screen background, clip it to the window size, blur it a
		506	bit, align it to the window position and use it as background.
		507
		508	clip move -TX, -TY, keep { blur 5, root }
		509
		510	=cut
		511
		512	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
		513	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
		514	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
		515	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
		516
		517	=item now
		518
		519	Returns the current time as (fractional) seconds since the epoch.
		520
		521	Using this expression does I<not> make your expression sensitive to time,
		522	but the next two functions do.
		523
		524	=item again $seconds
		525
		526	When this function is used the expression will be reevaluated again in
		527	C<$seconds> seconds.
		528
		529	Example: load some image and rotate it according to the time of day (as if it were
		530	the hour pointer of a clock). Update this image every minute.
		531
		532	again 60;
		533	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
		534
		535	=item counter $seconds
		536
		537	Like C<again>, but also returns an increasing counter value, starting at
		538	0, which might be useful for some simple animation effects.
		539
		540	=cut
		541
		542	sub now() { urxvt::NOW }
		543
		544	sub again($) {
		545	$frame->[FR_AGAIN]{time} = $_[0];
		546	}
		547
448	sub clone($) {	548	sub counter($) {
449	$_[0]->clone	549	$frame->[FR_AGAIN]{time} = $_[0];
		550	$frame->[FR_STATE]{counter} + 0
450	}	551	}
		552
		553	=back
		554
		555	=head2 SHAPE CHANGING OPERATORS
		556
		557	The following operators modify the shape, size or position of the image.
		558
		559	=over 4
451		560
452	=item clip $img	561	=item clip $img
453		562
454	=item clip $width, $height, $img	563	=item clip $width, $height, $img
455		564
…		…
466	assumed.	575	assumed.
467		576
468	Example: load an image, blur it, and clip it to the window size to save	577	Example: load an image, blur it, and clip it to the window size to save
469	memory.	578	memory.
470		579
471	clip blur 10, load "mybg.png"	580	clip keep { blur 10, load "mybg.png" }
472		581
473	=cut	582	=cut
474		583
475	sub clip($;$$;$$) {	584	sub clip($;$$;$$) {
476	my $img = pop;	585	my $img = pop;
…		…
479	$img->sub_rect ($_[0], $_[1], $w, $h)	588	$img->sub_rect ($_[0], $_[1], $w, $h)
480	}	589	}
481		590
482	=item scale $img	591	=item scale $img
483		592
484	=item scale $size_percent, $img	593	=item scale $size_factor, $img
485		594
486	=item scale $width_percent, $height_percent, $img	595	=item scale $width_factor, $height_factor, $img
487		596
488	Scales the image by the given percentages in horizontal	597	Scales the image by the given factors in horizontal
489	(C<$width_percent>) and vertical (C<$height_percent>) direction.	598	(C<$width>) and vertical (C<$height>) direction.
490		599
491	If only one percentage is give, it is used for both directions.	600	If only one factor is give, it is used for both directions.
492		601
493	If no percentages are given, scales the image to the window size without	602	If no factors are given, scales the image to the window size without
494	keeping aspect.	603	keeping aspect.
495		604
496	=item resize $width, $height, $img	605	=item resize $width, $height, $img
497		606
498	Resizes the image to exactly C<$width> times C<$height> pixels.	607	Resizes the image to exactly C<$width> times C<$height> pixels.
499		608
500	=cut	609	=item fit $img
501		610
502	#TODO: maximise, maximise_fill?	611	=item fit $width, $height, $img
		612
		613	Fits the image into the given C<$width> and C<$height> without changing
		614	aspect, or the terminal size. That means it will be shrunk or grown until
		615	the whole image fits into the given area, possibly leaving borders.
		616
		617	=item cover $img
		618
		619	=item cover $width, $height, $img
		620
		621	Similar to C<fit>, but shrinks or grows until all of the area is covered
		622	by the image, so instead of potentially leaving borders, it will cut off
		623	image data that doesn't fit.
		624
		625	=cut
503		626
504	sub scale($;$;$) {	627	sub scale($;$;$) {
505	my $img = pop;	628	my $img = pop;
506		629
507	@_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01)	630	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
508	: @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01)	631	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
509	: $img->scale (TW, TH)	632	: $img->scale (TW, TH)
510	}	633	}
511		634
512	sub resize($$$) {	635	sub resize($$$) {
513	my $img = pop;	636	my $img = pop;
514	$img->scale ($_[0], $_[1])	637	$img->scale ($_[0], $_[1])
515	}	638	}
516		639
		640	sub fit($;$$) {
		641	my $img = pop;
		642	my $w = ($_[0] \|\| TW) / $img->w;
		643	my $h = ($_[1] \|\| TH) / $img->h;
		644	scale +(min $w, $h), $img
		645	}
		646
		647	sub cover($;$$) {
		648	my $img = pop;
		649	my $w = ($_[0] \|\| TW) / $img->w;
		650	my $h = ($_[1] \|\| TH) / $img->h;
		651	scale +(max $w, $h), $img
		652	}
		653
517	=item move $dx, $dy, $img	654	=item move $dx, $dy, $img
518		655
519	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in	656	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
520	the vertical.	657	the vertical.
521		658
522	Example: move the image right by 20 pixels and down by 30.	659	Example: move the image right by 20 pixels and down by 30.
523		660
524	move 20, 30, ...	661	move 20, 30, ...
		662
		663	=item align $xalign, $yalign, $img
		664
		665	Aligns the image according to a factor - C<0> means the image is moved to
		666	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		667	exactly centered and C<1> means it touches the right or bottom edge.
		668
		669	Example: remove any visible border around an image, center it vertically but move
		670	it to the right hand side.
		671
		672	align 1, 0.5, pad $img
		673
		674	=item center $img
		675
		676	=item center $width, $height, $img
		677
		678	Centers the image, i.e. the center of the image is moved to the center of
		679	the terminal window (or the box specified by C<$width> and C<$height> if
		680	given).
		681
		682	Example: load an image and center it.
		683
		684	center keep { pad load "mybg.png" }
525		685
526	=item rootalign $img	686	=item rootalign $img
527		687
528	Moves the image so that it appears glued to the screen as opposed to the	688	Moves the image so that it appears glued to the screen as opposed to the
529	window. This gives the illusion of a larger area behind the window. It is	689	window. This gives the illusion of a larger area behind the window. It is
530	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	690	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
531	top left of the screen.	691	top left of the screen.
532		692
533	Example: load a background image, put it in mirror mode and root align it.	693	Example: load a background image, put it in mirror mode and root align it.
534		694
535	rootalign mirror load "mybg.png"	695	rootalign keep { mirror load "mybg.png" }
536		696
537	Example: take the screen background and align it, giving the illusion of	697	Example: take the screen background and align it, giving the illusion of
538	transparency as long as the window isn't in front of other windows.	698	transparency as long as the window isn't in front of other windows.
539		699
540	rootalign root	700	rootalign root
541		701
542	=cut	702	=cut
543		703
544	sub move($$;$) {	704	sub move($$;$) {
545	my $img = pop->clone;	705	my $img = pop->clone;
546	$img->move ($_[0], $_[1]);	706	$img->move ($_[0], $_[1]);
547	$img	707	$img
548	}	708	}
549		709
		710	sub align($;$$) {
		711	my $img = pop;
		712
		713	move $_[0] * (TW - $img->w),
		714	$_[1] * (TH - $img->h),
		715	$img
		716	}
		717
		718	sub center($;$$) {
		719	my $img = pop;
		720	my $w = $_[0] \|\| TW;
		721	my $h = $_[1] \|\| TH;
		722
		723	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		724	}
		725
550	sub rootalign($) {	726	sub rootalign($) {
551	move -TX, -TY, $_[0]	727	move -TX, -TY, $_[0]
552	}	728	}
553		729
		730	=item rotate $center_x, $center_y, $degrees, $img
		731
		732	Rotates the image clockwise by C<$degrees> degrees, around the point at
		733	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		734
		735	Example: rotate the image by 90 degrees around it's center.
		736
		737	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		738
		739	=cut
		740
		741	sub rotate($$$$) {
		742	my $img = pop;
		743	$img->rotate (
		744	$_[0] * ($img->w + $img->x),
		745	$_[1] * ($img->h + $img->y),
		746	$_[2] * (3.14159265 / 180),
		747	)
		748	}
		749
		750	=back
		751
		752	=head2 COLOUR MODIFICATIONS
		753
		754	The following operators change the pixels of the image.
		755
		756	=over 4
		757
554	=item contrast $factor, $img	758	=item contrast $factor, $img
555		759
556	=item contrast $r, $g, $b, $img	760	=item contrast $r, $g, $b, $img
557		761
558	=item contrast $r, $g, $b, $a, $img	762	=item contrast $r, $g, $b, $a, $img
559		763
560	Adjusts the I<contrast> of an image.	764	Adjusts the I<contrast> of an image.
561		765
562	#TODO#	766	The first form applies a single C<$factor> to red, green and blue, the
		767	second form applies separate factors to each colour channel, and the last
		768	form includes the alpha channel.
563		769
		770	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		771	contrast.
		772
		773	Due to limitations in the underlying XRender extension, lowering contrast
		774	also reduces brightness, while increasing contrast currently also
		775	increases brightness.
		776
564	=item brightness $factor, $img	777	=item brightness $bias, $img
565		778
566	=item brightness $r, $g, $b, $img	779	=item brightness $r, $g, $b, $img
567		780
568	=item brightness $r, $g, $b, $a, $img	781	=item brightness $r, $g, $b, $a, $img
569		782
570	Adjusts the brightness of an image.	783	Adjusts the brightness of an image.
		784
		785	The first form applies a single C<$bias> to red, green and blue, the
		786	second form applies separate biases to each colour channel, and the last
		787	form includes the alpha channel.
		788
		789	Values less than 0 reduce brightness, while values larger than 0 increase
		790	it. Useful range is from -1 to 1 - the former results in a black, the
		791	latter in a white picture.
		792
		793	Due to idiosyncrasies in the underlying XRender extension, biases less
		794	than zero can be I<very> slow.
571		795
572	=cut	796	=cut
573		797
574	sub contrast($$;$$;$) {	798	sub contrast($$;$$;$) {
575	my $img = pop;	799	my $img = pop;
576	my ($r, $g, $b, $a) = @_;	800	my ($r, $g, $b, $a) = @_;
577		801
578	($g, $b) = ($r, $r) if @_ < 4;	802	($g, $b) = ($r, $r) if @_ < 3;
579	$a = 1 if @_ < 5;	803	$a = 1 if @_ < 4;
580		804
581	$img = $img->clone;	805	$img = $img->clone;
582	$img->contrast ($r, $g, $b, $a);	806	$img->contrast ($r, $g, $b, $a);
583	$img	807	$img
584	}	808	}
585		809
586	sub brightness($$;$$;$) {	810	sub brightness($$;$$;$) {
587	my $img = pop;	811	my $img = pop;
588	my ($r, $g, $b, $a) = @_;	812	my ($r, $g, $b, $a) = @_;
589		813
590	($g, $b) = ($r, $r) if @_ < 4;	814	($g, $b) = ($r, $r) if @_ < 3;
591	$a = 1 if @_ < 5;	815	$a = 1 if @_ < 4;
592		816
593	$img = $img->clone;	817	$img = $img->clone;
594	$img->brightness ($r, $g, $b, $a);	818	$img->brightness ($r, $g, $b, $a);
595	$img	819	$img
596	}	820	}
…		…
612	sub blur($$;$) {	836	sub blur($$;$) {
613	my $img = pop;	837	my $img = pop;
614	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	838	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
615	}	839	}
616		840
617	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
618
619	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
620	pointer at C<$center_x> and C<$center_y> (specified as percentage of image
621	width/height), generating a new image with width C<$new_width> and height
622	C<$new_height>.
623
624	#TODO# new width, height, maybe more operators?
625
626	Example: rotate the image by 90 degrees
627
628	=cut
629
630	sub rotate($$$$$$) {
631	my $img = pop;
632	$img->rotate (
633	$_[0],
634	$_[1],
635	$_[2] * $img->w * .01,
636	$_[3] * $img->h * .01,
637	$_[4] * (3.14159265 / 180),
638	)
639	}
640
641	=back	841	=back
642		842
		843	=head2 OTHER STUFF
		844
		845	Anything that didn't fit any of the other categories, even after applying
		846	force and closing our eyes.
		847
		848	=over 4
		849
		850	=item once { ... }
		851
		852	This function takes a code block as argument, that is, one or more
		853	statements enclosed by braces.
		854
		855	The trick is that this code block is only evaluated once - future calls
		856	will simply return the original image (yes, it should only be used with
		857	images).
		858
		859	This can be extremely useful to avoid redoing the same slow operations
		860	again and again- for example, if your background expression takes the root
		861	background, blurs it and then root-aligns it it would have to blur the
		862	root background on every window move or resize.
		863
		864	In fact, urxvt itself encloses the whole expression in some kind of
		865	C<once> block so it only is reevaluated as required.
		866
		867	Putting the blur into a C<once> block will make sure the blur is only done
		868	once:
		869
		870	rootlign once { blur 10, root }
		871
		872	This leaves the question of how to force reevaluation of the block,
		873	in case the root background changes: If expression inside the block
		874	is sensitive to some event (root background changes, window geometry
		875	changes), then it will be reevaluated automatically as needed.
		876
		877	=item once_again
		878
		879	Resets all C<once> block as if they had never been called, i.e. on the
		880	next call they will be reevaluated again.
		881
		882	=cut
		883
		884	sub once(&) {
		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 once_again() {
		913	delete $self->{frame_cache};
		914	}
		915
		916	=back
		917
643	=cut	918	=cut
644		919
645	}	920	}
646		921
647	sub parse_expr {	922	sub parse_expr {
648	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	. "}";
649	die if $@;	929	die if $@;
650	$expr	930	$expr
651	}	931	}
652		932
653	# compiles a parsed expression	933	# compiles a parsed expression
654	sub set_expr {	934	sub set_expr {
655	my ($self, $expr) = @_;	935	my ($self, $expr) = @_;
656		936
		937	$self->{root} = [];
657	$self->{expr} = $expr;	938	$self->{expr} = $expr;
658	$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 $state->{rootpmap};
		987	}
659	}	988	}
660		989
661	# evaluate the current bg expression	990	# evaluate the current bg expression
662	sub recalculate {	991	sub recalculate {
663	my ($arg_self) = @_;	992	my ($arg_self) = @_;
…		…
673		1002
674	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1003	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
675		1004
676	# set environment to evaluate user expression	1005	# set environment to evaluate user expression
677		1006
678	local $self = $arg_self;	1007	local $self = $arg_self;
679
680	local $HOME = $ENV{HOME};	1008	local $HOME = $ENV{HOME};
681	local $old = $self->{state};	1009	local $frame = [];
682	local $new = my $state = $self->{state} = {};
683		1010
684	($x, $y, $w, $h) =
685	$self->background_geometry ($self->{border});	1011	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
686		1012
687	# evaluate user expression	1013	# evaluate user expression
688		1014
689	my $img = eval { $self->{expr}->() };	1015	my @img = eval { $self->{expr}->() };
690	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"
691	die if !UNIVERSAL::isa $img, "urxvt::img";	1019	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
692		1020
693	$state->{size_sensitive} = 1	1021	my $img = urxvt::bgdsl::merge @img;
		1022
		1023	$frame->[FR_AGAIN]{size} = 1
694	if $img->repeat_mode != urxvt::RepeatNormal;	1024	if $img->repeat_mode != urxvt::RepeatNormal;
695		1025
696	# if the expression is sensitive to external events, prepare reevaluation then	1026	# if the expression is sensitive to external events, prepare reevaluation then
697		1027	$self->compile_frame ($frame, sub { $arg_self->recalculate });
698	my $repeat;
699
700	if (my $again = $state->{again}) {
701	$repeat = 1;
702	my $self = $self;
703	$state->{timer} = $again == $old->{again}
704	? $old->{timer}
705	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
706	++$self->{counter};
707	$self->recalculate
708	});
709	}
710
711	if (delete $state->{position_sensitive}) {
712	$repeat = 1;
713	$self->enable (position_change => sub { $_[0]->recalculate });
714	} else {
715	$self->disable ("position_change");
716	}
717
718	if (delete $state->{size_sensitive}) {
719	$repeat = 1;
720	$self->enable (size_change => sub { $_[0]->recalculate });
721	} else {
722	$self->disable ("size_change");
723	}
724
725	if (delete $state->{rootpmap_sensitive}) {
726	$repeat = 1;
727	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
728	} else {
729	$self->disable ("rootpmap_change");
730	}
731		1028
732	# clear stuff we no longer need	1029	# clear stuff we no longer need
733		1030
734	%$old = ();	1031	# unless (%{ $frame->[FR_STATE] }) {
735
736	unless ($repeat) {
737	delete $self->{state};	1032	# delete $self->{state};
738	delete $self->{expr};	1033	# delete $self->{expr};
739	}	1034	# }
740		1035
741	# set background pixmap	1036	# set background pixmap
742		1037
743	$self->set_background ($img, $self->{border});	1038	$self->set_background ($img, $self->{border});
744	$self->scr_recolour (0);	1039	$self->scr_recolour (0);
…		…
746	}	1041	}
747		1042
748	sub on_start {	1043	sub on_start {
749	my ($self) = @_;	1044	my ($self) = @_;
750		1045
751	my $expr = $self->x_resource ("background.expr")	1046	my $expr = $self->x_resource ("%.expr")
752	or return;	1047	or return;
753		1048
		1049	$self->has_render
		1050	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1051
754	$self->set_expr (parse_expr $expr);	1052	$self->set_expr (parse_expr $expr);
755	$self->{border} = $self->x_resource_boolean ("background.border");	1053	$self->{border} = $self->x_resource_boolean ("%.border");
		1054
		1055	$MIN_INTERVAL = $self->x_resource ("%.interval");
756		1056
757	()	1057	()
758	}	1058	}
759		1059

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.41 by root, Fri Jun 8 22:21:48 2012 UTC vs. Revision 1.65 by sf-exg, Wed Jun 20 18:18:14 2012 UTC

Diff Legend

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.41 by root, Fri Jun 8 22:21:48 2012 UTC vs.
Revision 1.65 by sf-exg, Wed Jun 20 18:18:14 2012 UTC