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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.42 by root, Sun Jun 10 10:42:19 2012 UTC vs.
Revision 1.70 by root, Mon Jul 2 01:35:37 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 inner expression is evaluated once per hour (and whenever the
		79	temrinal window is resized). It sets F<sunday.png> as background on
77	background on Sundays, and F<weekday.png> on all other days.	80	Sundays, and F<weekday.png> on all other days.
78		81
79	Fortunately, we expect that most expressions will be much simpler, with	82	Fortunately, we expect that most expressions will be much simpler, with
80	little Perl knowledge needed.	83	little Perl knowledge needed.
81		84
82	Basically, you always start with a function that "generates" an image	85	Basically, you always start with a function that "generates" an image
…		…
99	its result becomes the argument to the C<scale> function.	102	its result becomes the argument to the C<scale> function.
100		103
101	Many operators also allow some parameters preceding the input image	104	Many operators also allow some parameters preceding the input image
102	that modify its behaviour. For example, C<scale> without any additional	105	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	106	arguments scales the image to size of the terminal window. If you specify
104	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):
105		109
106	scale 200, load "$HOME/mypic.png"	110	scale 2, load "$HOME/mypic.png"
107		111
108	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>
109	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
110	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
111	commas.	115	commas.
112		116
113	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
114	horizontal and vertical dimensions. For example, this halves the image	118	horizontal and vertical dimensions. For example, this halves the image
115	width and doubles the image height:	119	width and doubles the image height:
116		120
117	scale 50, 200, load "$HOME/mypic.png"	121	scale 0.5, 2, load "$HOME/mypic.png"
118		122
119	Other effects than scalign are also readily available, for exmaple, you can	123	IF you try out these expressions, you might suffer from some sluggishness,
120	tile the image to fill the whole window, instead of resizing it:	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:
121		127
		128	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		129
		130	The C<keep> operator executes all the statements inside the braces only
		131	once, or when it thinks the outcome might change. In other cases it
		132	returns the last value computed by the brace block.
		133
		134	This means that the C<load> is only executed once, which makes it much
		135	faster, but also means that more memory is being used, because the loaded
		136	image must be kept in memory at all times. In this expression, the
		137	trade-off is likely worth it.
		138
		139	But back to effects: Other effects than scaling are also readily
		140	available, for example, you can tile the image to fill the whole window,
		141	instead of resizing it:
		142
122	tile load "$HOME/mypic.png"	143	tile keep { load "$HOME/mypic.png" }
123		144
124	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator	145	In fact, images returned by C<load> are in C<tile> mode by default, so the
125	is kind of superfluous.	146	C<tile> operator is kind of superfluous.
126		147
127	Another common effect is to mirror the image, so that the same edges touch:	148	Another common effect is to mirror the image, so that the same edges
		149	touch:
128		150
129	mirror load "$HOME/mypic.png"	151	mirror keep { load "$HOME/mypic.png" }
130		152
131	This is also a typical background expression:	153	Another common background expression is:
132		154
133	rootalign root	155	rootalign root
134		156
135	It first takes a snapshot of the screen background image, and then	157	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	158	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	159	left corner of the terminal window)- the result is pseudo-transparency:
138	moved around.	160	the image seems to be static while the window is moved around.
139		161
140	=head2 CYCLES AND CACHING	162	=head2 CACHING AND SENSITIVITY
141		163
142	As has been mentioned before, the expression might be evaluated multiple	164	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	165	caching results can be very important for a smooth operation. Caching can
144	have begun. Many operators cache their results till the next cycle.	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.
145		169
146	For example, the C<load> operator keeps a copy of the image. If it is	170	=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		171
150	This only works for one cycle though, so as long as you load the same	172	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	173	... }>. The C<keep> operator takes a block of multiple statements enclosed
152	image, it will forget about the first one.	174	by C<{}> and keeps the return value in memory.
153		175
154	This allows you to either speed things up by keeping multiple images in	176	An expression can be "sensitive" to various external events, such as
155	memory, or comserve memory by loading images more often.	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.
156		183
157	For example, you can keep two images in memory and use a random one like	184	When such an event happens, C<keep> will automatically trigger a
158	this:	185	reevaluation of the whole expression with the new value of the expression.
159		186
160	my $img1 = load "img1.png";	187	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		188
164	Since both images are "loaded" every time the expression is evaluated,	189	rootalign keep { blur 20, root }
165	they are always kept in memory. Contrast this version:
166		190
167	my $path1 = "img1.png";	191	This makes a blurred copy of the root background once, and on subsequent
168	my $path2 = "img2.png";	192	calls, just root-aligns it. Since C<blur> is usually quite slow and
169	load ((0.5 > rand) ? $path1 : $path2)	193	C<rootalign> is quite fast, this trades extra memory (for the cached
		194	blurred pixmap) with speed (blur only needs to be redone when root
		195	changes).
170		196
171	Here, a path is selected randomly, and load is only called for one image,	197	=head3 C<load> caching
172	so keeps only one image in memory. If, on the next evaluation, luck	198
173	decides to use the other path, then it will have to load that image again.	199	The C<load> operator itself does not keep images in memory, but as long as
		200	the image is still in memory, C<load> will use the in-memory image instead
		201	of loading it freshly from disk.
		202
		203	That means that this expression:
		204
		205	keep { load "$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.
174		209
175	=head1 REFERENCE	210	=head1 REFERENCE
176		211
177	=head2 COMMAND LINE SWITCHES	212	=head2 COMMAND LINE SWITCHES
178		213
…		…
188	overwriting borders and any other areas, such as the scrollbar.	223	overwriting borders and any other areas, such as the scrollbar.
189		224
190	Specifying this flag changes the behaviour, so that the image only	225	Specifying this flag changes the behaviour, so that the image only
191	replaces the background of the character area.	226	replaces the background of the character area.
192		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
193	=back	237	=back
194		238
195	=cut	239	=cut
196		240
		241	our %_IMG_CACHE;
197	our $HOME;	242	our $HOME;
198	our ($self, $old, $new);	243	our ($self, $frame);
199	our ($x, $y, $w, $h);	244	our ($x, $y, $w, $h);
200		245
201	# enforce at least this interval between updates	246	# enforce at least this interval between updates
202	our $MIN_INTERVAL = 1/100;	247	our $MIN_INTERVAL = 6/59.951;
203		248
204	{	249	{
205	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);
206		258
207	=head2 PROVIDERS/GENERATORS	259	=head2 PROVIDERS/GENERATORS
208		260
209	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
210	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
…		…
215	=item load $path	267	=item load $path
216		268
217	Loads the image at the given C<$path>. The image is set to plane tiling	269	Loads the image at the given C<$path>. The image is set to plane tiling
218	mode.	270	mode.
219		271
220	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.
		274
		275	=item load_uc $path
		276
		277	Load uncached - same as load, but does not cache the image, which means it
		278	is I<always> loaded from the filesystem again.
221		279
222	=cut	280	=cut
223		281
224	sub load($) {	282	sub load($) {
225	my ($path) = @_;	283	my ($path) = @_;
226		284
227	$new->{load}{$path} = $old->{load}{$path} \|\| $self->new_img_from_file ($path);	285	$_IMG_CACHE{$path} \|\| do {
		286	my $img = $self->new_img_from_file ($path);
		287	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		288	$img
		289	}
228	}	290	}
229		291
230	=item root	292	=item root
231		293
232	Returns the root window pixmap, that is, hopefully, the background image	294	Returns the root window pixmap, that is, hopefully, the background image
233	of your screen. The image is set to extend mode.	295	of your screen.
234		296
235	This function makes your expression root sensitive, that means it will be	297	This function makes your expression root sensitive, that means it will be
236	reevaluated when the bg image changes.	298	reevaluated when the bg image changes.
237		299
238	=cut	300	=cut
239		301
240	sub root() {	302	sub root() {
241	$new->{rootpmap_sensitive} = 1;	303	$frame->[FR_AGAIN]{rootpmap} = 1;
242	die "root op not supported, exg, we need you";	304	$self->new_img_from_root
243	}	305	}
244		306
245	=item solid $colour	307	=item solid $colour
246		308
247	=item solid $width, $height, $colour	309	=item solid $width, $height, $colour
…		…
255	=cut	317	=cut
256		318
257	sub solid($;$$) {	319	sub solid($;$$) {
258	my $colour = pop;	320	my $colour = pop;
259		321
260	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	322	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
261	$img->fill ($colour);	323	$img->fill ($colour);
262	$img	324	$img
263	}	325	}
264		326
265	=back	327	=item clone $img
266		328
267	=head2 VARIABLES	329	Returns an exact copy of the image. This is useful if you want to have
		330	multiple copies of the same image to apply different effects to.
268		331
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	332	=cut
311		333
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} = $_[0];
345	}
346
347	sub counter($) {	334	sub clone($) {
348	$new->{again} = $_[0];	335	$_[0]->clone
349	$self->{counter} + 0
350	}	336	}
351		337
352	=back	338	=item merge $img ...
		339
		340	Takes any number of images and merges them together, creating a single
		341	image containing them all. The tiling mode of the first image is used as
		342	the tiling mode of the resulting image.
		343
		344	This function is called automatically when an expression returns multiple
		345	images.
		346
		347	=cut
		348
		349	sub merge(@) {
		350	return $_[0] unless $#_;
		351
		352	# rather annoyingly clumsy, but optimisation is for another time
		353
		354	my $x0 = +1e9;
		355	my $y0 = +1e9;
		356	my $x1 = -1e9;
		357	my $y1 = -1e9;
		358
		359	for (@_) {
		360	my ($x, $y, $w, $h) = $_->geometry;
		361
		362	$x0 = $x if $x0 > $x;
		363	$y0 = $y if $y0 > $y;
		364
		365	$x += $w;
		366	$y += $h;
		367
		368	$x1 = $x if $x1 < $x;
		369	$y1 = $y if $y1 < $y;
		370	}
		371
		372	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		373	$base->repeat_mode ($_[0]->repeat_mode);
		374	$base->fill ([0, 0, 0, 0]);
		375
		376	$base->draw ($_)
		377	for @_;
		378
		379	$base
		380	}
353		381
354	=head2 TILING MODES	382	=head2 TILING MODES
355		383
356	The following operators modify the tiling mode of an image, that is, the	384	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.	385	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	415	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	416	image over another image or the background colour while leaving all
389	background pixels outside the image unchanged.	417	background pixels outside the image unchanged.
390		418
391	Example: load an image and display it in the upper left corner. The rest	419	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	420	of the space is left "empty" (transparent or whatever your compositor does
393	in alpha mode, else background colour).	421	in alpha mode, else background colour).
394		422
395	pad load "mybg.png"	423	pad load "mybg.png"
396		424
397	=item extend $img	425	=item extend $img
398		426
399	Extends the image over the whole plane, using the closest pixel in the	427	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	428	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	429	filtering operations and want the pixels outside the image to have the
402	same values as the pixels near the edge.	430	same values as the pixels near the edge.
403		431
404	Example: just for curiosity, how does this pixel extension stuff work?	432	Example: just for curiosity, how does this pixel extension stuff work?
405		433
…		…
431	$img	459	$img
432	}	460	}
433		461
434	=back	462	=back
435		463
436	=head2 PIXEL OPERATORS	464	=head2 VARIABLE VALUES
437		465
438	The following operators modify the image pixels in various ways.	466	The following functions provide variable data such as the terminal window
		467	dimensions. They are not (Perl-) variables, they just return stuff that
		468	varies. Most of them make your expression sensitive to some events, for
		469	example using C<TW> (terminal width) means your expression is evaluated
		470	again when the terminal is resized.
439		471
440	=over 4	472	=over 4
441		473
442	=item clone $img	474	=item TX
443		475
444	Returns an exact copy of the image.	476	=item TY
445		477
446	=cut	478	Return the X and Y coordinates of the terminal window (the terminal
		479	window is the full window by default, and the character area only when in
		480	border-respect mode).
447		481
		482	Using these functions make your expression sensitive to window moves.
		483
		484	These functions are mainly useful to align images to the root window.
		485
		486	Example: load an image and align it so it looks as if anchored to the
		487	background (that's exactly what C<rootalign> does btw.):
		488
		489	move -TX, -TY, keep { load "mybg.png" }
		490
		491	=item TW
		492
		493	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		494	terminal window is the full window by default, and the character area only
		495	when in border-respect mode).
		496
		497	Using these functions make your expression sensitive to window resizes.
		498
		499	These functions are mainly useful to scale images, or to clip images to
		500	the window size to conserve memory.
		501
		502	Example: take the screen background, clip it to the window size, blur it a
		503	bit, align it to the window position and use it as background.
		504
		505	clip move -TX, -TY, keep { blur 5, root }
		506
		507	=cut
		508
		509	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
		510	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
		511	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
		512	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
		513
		514	=item now
		515
		516	Returns the current time as (fractional) seconds since the epoch.
		517
		518	Using this expression does I<not> make your expression sensitive to time,
		519	but the next two functions do.
		520
		521	=item again $seconds
		522
		523	When this function is used the expression will be reevaluated again in
		524	C<$seconds> seconds.
		525
		526	Example: load some image and rotate it according to the time of day (as if it were
		527	the hour pointer of a clock). Update this image every minute.
		528
		529	again 60;
		530	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
		531
		532	=item counter $seconds
		533
		534	Like C<again>, but also returns an increasing counter value, starting at
		535	0, which might be useful for some simple animation effects.
		536
		537	=cut
		538
		539	sub now() { urxvt::NOW }
		540
		541	sub again($) {
		542	$frame->[FR_AGAIN]{time} = $_[0];
		543	}
		544
448	sub clone($) {	545	sub counter($) {
449	$_[0]->clone	546	$frame->[FR_AGAIN]{time} = $_[0];
		547	$frame->[FR_STATE]{counter} + 0
450	}	548	}
		549
		550	=back
		551
		552	=head2 SHAPE CHANGING OPERATORS
		553
		554	The following operators modify the shape, size or position of the image.
		555
		556	=over 4
451		557
452	=item clip $img	558	=item clip $img
453		559
454	=item clip $width, $height, $img	560	=item clip $width, $height, $img
455		561
…		…
466	assumed.	572	assumed.
467		573
468	Example: load an image, blur it, and clip it to the window size to save	574	Example: load an image, blur it, and clip it to the window size to save
469	memory.	575	memory.
470		576
471	clip blur 10, load "mybg.png"	577	clip keep { blur 10, load "mybg.png" }
472		578
473	=cut	579	=cut
474		580
475	sub clip($;$$;$$) {	581	sub clip($;$$;$$) {
476	my $img = pop;	582	my $img = pop;
…		…
479	$img->sub_rect ($_[0], $_[1], $w, $h)	585	$img->sub_rect ($_[0], $_[1], $w, $h)
480	}	586	}
481		587
482	=item scale $img	588	=item scale $img
483		589
484	=item scale $size_percent, $img	590	=item scale $size_factor, $img
485		591
486	=item scale $width_percent, $height_percent, $img	592	=item scale $width_factor, $height_factor, $img
487		593
488	Scales the image by the given percentages in horizontal	594	Scales the image by the given factors in horizontal
489	(C<$width_percent>) and vertical (C<$height_percent>) direction.	595	(C<$width>) and vertical (C<$height>) direction.
490		596
491	If only one percentage is give, it is used for both directions.	597	If only one factor is give, it is used for both directions.
492		598
493	If no percentages are given, scales the image to the window size without	599	If no factors are given, scales the image to the window size without
494	keeping aspect.	600	keeping aspect.
495		601
496	=item resize $width, $height, $img	602	=item resize $width, $height, $img
497		603
498	Resizes the image to exactly C<$width> times C<$height> pixels.	604	Resizes the image to exactly C<$width> times C<$height> pixels.
499		605
500	=cut	606	=item fit $img
501		607
502	#TODO: maximise, maximise_fill?	608	=item fit $width, $height, $img
		609
		610	Fits the image into the given C<$width> and C<$height> without changing
		611	aspect, or the terminal size. That means it will be shrunk or grown until
		612	the whole image fits into the given area, possibly leaving borders.
		613
		614	=item cover $img
		615
		616	=item cover $width, $height, $img
		617
		618	Similar to C<fit>, but shrinks or grows until all of the area is covered
		619	by the image, so instead of potentially leaving borders, it will cut off
		620	image data that doesn't fit.
		621
		622	=cut
503		623
504	sub scale($;$;$) {	624	sub scale($;$;$) {
505	my $img = pop;	625	my $img = pop;
506		626
507	@_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01)	627	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
508	: @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01)	628	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
509	: $img->scale (TW, TH)	629	: $img->scale (TW, TH)
510	}	630	}
511		631
512	sub resize($$$) {	632	sub resize($$$) {
513	my $img = pop;	633	my $img = pop;
514	$img->scale ($_[0], $_[1])	634	$img->scale ($_[0], $_[1])
515	}	635	}
516		636
		637	sub fit($;$$) {
		638	my $img = pop;
		639	my $w = ($_[0] \|\| TW) / $img->w;
		640	my $h = ($_[1] \|\| TH) / $img->h;
		641	scale +(min $w, $h), $img
		642	}
		643
		644	sub cover($;$$) {
		645	my $img = pop;
		646	my $w = ($_[0] \|\| TW) / $img->w;
		647	my $h = ($_[1] \|\| TH) / $img->h;
		648	scale +(max $w, $h), $img
		649	}
		650
517	=item move $dx, $dy, $img	651	=item move $dx, $dy, $img
518		652
519	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in	653	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
520	the vertical.	654	the vertical.
521		655
522	Example: move the image right by 20 pixels and down by 30.	656	Example: move the image right by 20 pixels and down by 30.
523		657
524	move 20, 30, ...	658	move 20, 30, ...
		659
		660	=item align $xalign, $yalign, $img
		661
		662	Aligns the image according to a factor - C<0> means the image is moved to
		663	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		664	exactly centered and C<1> means it touches the right or bottom edge.
		665
		666	Example: remove any visible border around an image, center it vertically but move
		667	it to the right hand side.
		668
		669	align 1, 0.5, pad $img
		670
		671	=item center $img
		672
		673	=item center $width, $height, $img
		674
		675	Centers the image, i.e. the center of the image is moved to the center of
		676	the terminal window (or the box specified by C<$width> and C<$height> if
		677	given).
		678
		679	Example: load an image and center it.
		680
		681	center keep { pad load "mybg.png" }
525		682
526	=item rootalign $img	683	=item rootalign $img
527		684
528	Moves the image so that it appears glued to the screen as opposed to the	685	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	686	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	687	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
531	top left of the screen.	688	top left of the screen.
532		689
533	Example: load a background image, put it in mirror mode and root align it.	690	Example: load a background image, put it in mirror mode and root align it.
534		691
535	rootalign mirror load "mybg.png"	692	rootalign keep { mirror load "mybg.png" }
536		693
537	Example: take the screen background and align it, giving the illusion of	694	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.	695	transparency as long as the window isn't in front of other windows.
539		696
540	rootalign root	697	rootalign root
541		698
542	=cut	699	=cut
543		700
544	sub move($$;$) {	701	sub move($$;$) {
545	my $img = pop->clone;	702	my $img = pop->clone;
546	$img->move ($_[0], $_[1]);	703	$img->move ($_[0], $_[1]);
547	$img	704	$img
548	}	705	}
549		706
		707	sub align($;$$) {
		708	my $img = pop;
		709
		710	move $_[0] * (TW - $img->w),
		711	$_[1] * (TH - $img->h),
		712	$img
		713	}
		714
		715	sub center($;$$) {
		716	my $img = pop;
		717	my $w = $_[0] \|\| TW;
		718	my $h = $_[1] \|\| TH;
		719
		720	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		721	}
		722
550	sub rootalign($) {	723	sub rootalign($) {
551	move -TX, -TY, $_[0]	724	move -TX, -TY, $_[0]
552	}	725	}
553		726
		727	=item rotate $center_x, $center_y, $degrees, $img
		728
		729	Rotates the image clockwise by C<$degrees> degrees, around the point at
		730	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		731
		732	Example: rotate the image by 90 degrees around it's center.
		733
		734	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		735
		736	=cut
		737
		738	sub rotate($$$$) {
		739	my $img = pop;
		740	$img->rotate (
		741	$_[0] * ($img->w + $img->x),
		742	$_[1] * ($img->h + $img->y),
		743	$_[2] * (3.14159265 / 180),
		744	)
		745	}
		746
		747	=back
		748
		749	=head2 COLOUR MODIFICATIONS
		750
		751	The following operators change the pixels of the image.
		752
		753	=over 4
		754
		755	=item tint $color, $img
		756
		757	Tints the image in the given colour.
		758
		759	Example: tint the image red.
		760
		761	tint "red", load "rgb.png"
		762
		763	Example: the same, but specify the colour by component.
		764
		765	tint [1, 0, 0], load "rgb.png"
		766
		767	=cut
		768
		769	sub tint($$) {
		770	$_[1]->tint ($_[0])
		771	}
		772
554	=item contrast $factor, $img	773	=item contrast $factor, $img
555		774
556	=item contrast $r, $g, $b, $img	775	=item contrast $r, $g, $b, $img
557		776
558	=item contrast $r, $g, $b, $a, $img	777	=item contrast $r, $g, $b, $a, $img
559		778
560	Adjusts the I<contrast> of an image.	779	Adjusts the I<contrast> of an image.
561		780
562	#TODO#	781	The first form applies a single C<$factor> to red, green and blue, the
		782	second form applies separate factors to each colour channel, and the last
		783	form includes the alpha channel.
563		784
		785	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		786	contrast.
		787
		788	Due to limitations in the underlying XRender extension, lowering contrast
		789	also reduces brightness, while increasing contrast currently also
		790	increases brightness.
		791
564	=item brightness $factor, $img	792	=item brightness $bias, $img
565		793
566	=item brightness $r, $g, $b, $img	794	=item brightness $r, $g, $b, $img
567		795
568	=item brightness $r, $g, $b, $a, $img	796	=item brightness $r, $g, $b, $a, $img
569		797
570	Adjusts the brightness of an image.	798	Adjusts the brightness of an image.
		799
		800	The first form applies a single C<$bias> to red, green and blue, the
		801	second form applies separate biases to each colour channel, and the last
		802	form includes the alpha channel.
		803
		804	Values less than 0 reduce brightness, while values larger than 0 increase
		805	it. Useful range is from -1 to 1 - the former results in a black, the
		806	latter in a white picture.
		807
		808	Due to idiosyncrasies in the underlying XRender extension, biases less
		809	than zero can be I<very> slow.
571		810
572	=cut	811	=cut
573		812
574	sub contrast($$;$$;$) {	813	sub contrast($$;$$;$) {
575	my $img = pop;	814	my $img = pop;
576	my ($r, $g, $b, $a) = @_;	815	my ($r, $g, $b, $a) = @_;
577		816
578	($g, $b) = ($r, $r) if @_ < 4;	817	($g, $b) = ($r, $r) if @_ < 3;
579	$a = 1 if @_ < 5;	818	$a = 1 if @_ < 4;
580		819
581	$img = $img->clone;	820	$img = $img->clone;
582	$img->contrast ($r, $g, $b, $a);	821	$img->contrast ($r, $g, $b, $a);
583	$img	822	$img
584	}	823	}
585		824
586	sub brightness($$;$$;$) {	825	sub brightness($$;$$;$) {
587	my $img = pop;	826	my $img = pop;
588	my ($r, $g, $b, $a) = @_;	827	my ($r, $g, $b, $a) = @_;
589		828
590	($g, $b) = ($r, $r) if @_ < 4;	829	($g, $b) = ($r, $r) if @_ < 3;
591	$a = 1 if @_ < 5;	830	$a = 1 if @_ < 4;
592		831
593	$img = $img->clone;	832	$img = $img->clone;
594	$img->brightness ($r, $g, $b, $a);	833	$img->brightness ($r, $g, $b, $a);
595	$img	834	$img
596	}	835	}
…		…
612	sub blur($$;$) {	851	sub blur($$;$) {
613	my $img = pop;	852	my $img = pop;
614	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	853	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
615	}	854	}
616		855
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	856	=back
642		857
		858	=head2 OTHER STUFF
		859
		860	Anything that didn't fit any of the other categories, even after applying
		861	force and closing our eyes.
		862
		863	=over 4
		864
		865	=item keep { ... }
		866
		867	This operator takes a code block as argument, that is, one or more
		868	statements enclosed by braces.
		869
		870	The trick is that this code block is only evaluated when the outcome
		871	changes - on other calls the C<keep> simply returns the image it computed
		872	previously (yes, it should only be used with images). Or in other words,
		873	C<keep> I<caches> the result of the code block so it doesn't need to be
		874	computed again.
		875
		876	This can be extremely useful to avoid redoing slow operations - for
		877	example, if your background expression takes the root background, blurs it
		878	and then root-aligns it it would have to blur the root background on every
		879	window move or resize.
		880
		881	Another example is C<load>, which can be quite slow.
		882
		883	In fact, urxvt itself encloses the whole expression in some kind of
		884	C<keep> block so it only is reevaluated as required.
		885
		886	Putting the blur into a C<keep> block will make sure the blur is only done
		887	once, while the C<rootalign> is still done each time the window moves.
		888
		889	rootlign keep { blur 10, root }
		890
		891	This leaves the question of how to force reevaluation of the block,
		892	in case the root background changes: If expression inside the block
		893	is sensitive to some event (root background changes, window geometry
		894	changes), then it will be reevaluated automatically as needed.
		895
		896	=cut
		897
		898	sub keep(&) {
		899	my $id = $_[0]+0;
		900
		901	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		902
		903	unless ($frame->[FR_CACHE]) {
		904	$frame->[FR_CACHE] = [ $_[0]() ];
		905
		906	my $self = $self;
		907	my $frame = $frame;
		908	Scalar::Util::weaken $frame;
		909	$self->compile_frame ($frame, sub {
		910	# clear this frame cache, also for all parents
		911	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		912	undef $frame->[FR_CACHE];
		913	}
		914
		915	$self->recalculate;
		916	});
		917	};
		918
		919	# in scalar context we always return the first original result, which
		920	# is not quite how perl works.
		921	wantarray
		922	? @{ $frame->[FR_CACHE] }
		923	: $frame->[FR_CACHE][0]
		924	}
		925
		926	# sub keep_clear() {
		927	# delete $self->{frame_cache};
		928	# }
		929
		930	=back
		931
643	=cut	932	=cut
644		933
645	}	934	}
646		935
647	sub parse_expr {	936	sub parse_expr {
648	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	937	my $expr = eval
		938	"sub {\n"
		939	. "package urxvt::bgdsl;\n"
		940	. "#line 0 'background expression'\n"
		941	. "$_[0]\n"
		942	. "}";
649	die if $@;	943	die if $@;
650	$expr	944	$expr
651	}	945	}
652		946
653	# compiles a parsed expression	947	# compiles a parsed expression
654	sub set_expr {	948	sub set_expr {
655	my ($self, $expr) = @_;	949	my ($self, $expr) = @_;
656		950
		951	$self->{root} = [];
657	$self->{expr} = $expr;	952	$self->{expr} = $expr;
658	$self->recalculate;	953	$self->recalculate;
		954	}
		955
		956	# takes a hash of sensitivity indicators and installs watchers
		957	sub compile_frame {
		958	my ($self, $frame, $cb) = @_;
		959
		960	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		961	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		962
		963	# don't keep stuff alive
		964	Scalar::Util::weaken $state;
		965
		966	if ($again->{nested}) {
		967	$state->{nested} = 1;
		968	} else {
		969	delete $state->{nested};
		970	}
		971
		972	if (my $interval = $again->{time}) {
		973	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		974	if $state->{time}[0] != $interval;
		975
		976	# callback might have changed, although we could just rule that out
		977	$state->{time}[1]->cb (sub {
		978	++$state->{counter};
		979	$cb->();
		980	});
		981	} else {
		982	delete $state->{time};
		983	}
		984
		985	if ($again->{position}) {
		986	$state->{position} = $self->on (position_change => $cb);
		987	} else {
		988	delete $state->{position};
		989	}
		990
		991	if ($again->{size}) {
		992	$state->{size} = $self->on (size_change => $cb);
		993	} else {
		994	delete $state->{size};
		995	}
		996
		997	if ($again->{rootpmap}) {
		998	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		999	} else {
		1000	delete $state->{rootpmap};
		1001	}
659	}	1002	}
660		1003
661	# evaluate the current bg expression	1004	# evaluate the current bg expression
662	sub recalculate {	1005	sub recalculate {
663	my ($arg_self) = @_;	1006	my ($arg_self) = @_;
…		…
673		1016
674	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1017	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
675		1018
676	# set environment to evaluate user expression	1019	# set environment to evaluate user expression
677		1020
678	local $self = $arg_self;	1021	local $self = $arg_self;
679
680	local $HOME = $ENV{HOME};	1022	local $HOME = $ENV{HOME};
681	local $old = $self->{state};	1023	local $frame = [];
682	local $new = my $state = $self->{state} = {};
683		1024
684	($x, $y, $w, $h) =
685	$self->background_geometry ($self->{border});	1025	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
686		1026
687	# evaluate user expression	1027	# evaluate user expression
688		1028
689	my $img = eval { $self->{expr}->() };	1029	my @img = eval { $self->{expr}->() };
690	warn $@ if $@;#d#	1030	die $@ if $@;
		1031	die "background-expr did not return anything.\n" unless @img;
		1032	die "background-expr: expected image(s), got something else.\n"
691	die if !UNIVERSAL::isa $img, "urxvt::img";	1033	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
692		1034
693	$state->{size_sensitive} = 1	1035	my $img = urxvt::bgdsl::merge @img;
		1036
		1037	$frame->[FR_AGAIN]{size} = 1
694	if $img->repeat_mode != urxvt::RepeatNormal;	1038	if $img->repeat_mode != urxvt::RepeatNormal;
695		1039
696	# if the expression is sensitive to external events, prepare reevaluation then	1040	# if the expression is sensitive to external events, prepare reevaluation then
697		1041	$self->compile_frame ($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	$self->disable ("rootpmap_change");
730	}
731		1042
732	# clear stuff we no longer need	1043	# clear stuff we no longer need
733		1044
734	%$old = ();	1045	# unless (%{ $frame->[FR_STATE] }) {
735
736	unless ($repeat) {
737	delete $self->{state};	1046	# delete $self->{state};
738	delete $self->{expr};	1047	# delete $self->{expr};
739	}	1048	# }
740		1049
741	# set background pixmap	1050	# set background pixmap
742		1051
743	$self->set_background ($img, $self->{border});	1052	$self->set_background ($img, $self->{border});
744	$self->scr_recolour (0);	1053	$self->scr_recolour (0);
…		…
746	}	1055	}
747		1056
748	sub on_start {	1057	sub on_start {
749	my ($self) = @_;	1058	my ($self) = @_;
750		1059
751	my $expr = $self->x_resource ("background.expr")	1060	my $expr = $self->x_resource ("%.expr")
752	or return;	1061	or return;
753		1062
		1063	$self->has_render
		1064	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1065
754	$self->set_expr (parse_expr $expr);	1066	$self->set_expr (parse_expr $expr);
755	$self->{border} = $self->x_resource_boolean ("background.border");	1067	$self->{border} = $self->x_resource_boolean ("%.border");
		1068
		1069	$MIN_INTERVAL = $self->x_resource ("%.interval");
756		1070
757	()	1071	()
758	}	1072	}
759		1073

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.42 by root, Sun Jun 10 10:42:19 2012 UTC vs. Revision 1.70 by root, Mon Jul 2 01:35:37 2012 UTC

Diff Legend

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.42 by root, Sun Jun 10 10:42:19 2012 UTC vs.
Revision 1.70 by root, Mon Jul 2 01:35:37 2012 UTC