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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.44 by root, Sun Jun 10 11:31:22 2012 UTC vs.
Revision 1.71 by root, Mon Jul 2 01:40:41 2012 UTC

…		…
1	#! perl	1	#! perl
2		2
3	#:META:X_RESOURCE:%.expr:string:background expression	3	#:META:X_RESOURCE:%.expr:string:background expression
4	#:META:X_RESOURCE:%.border.:boolean:respect the terminal border	4	#:META:X_RESOURCE:%.border:boolean:respect the terminal border
5		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
…		…
115	horizontal and vertical dimensions. For example, this halves the image	118	horizontal and vertical dimensions. For example, this halves the image
116	width and doubles the image height:	119	width and doubles the image height:
117		120
118	scale 0.5, 2, load "$HOME/mypic.png"	121	scale 0.5, 2, load "$HOME/mypic.png"
119		122
120	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,
121	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:
122		127
		128	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		129
		130	The C<keep> operator executes all the statements inside the braces only
		131	once, or when it thinks the outcome might change. In other cases it
		132	returns the last value computed by the brace block.
		133
		134	This means that the C<load> is only executed once, which makes it much
		135	faster, but also means that more memory is being used, because the loaded
		136	image must be kept in memory at all times. In this expression, the
		137	trade-off is likely worth it.
		138
		139	But back to effects: Other effects than scaling are also readily
		140	available, for example, you can tile the image to fill the whole window,
		141	instead of resizing it:
		142
123	tile load "$HOME/mypic.png"	143	tile keep { load "$HOME/mypic.png" }
124		144
125	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator	145	In fact, images returned by C<load> are in C<tile> mode by default, so the
126	is kind of superfluous.	146	C<tile> operator is kind of superfluous.
127		147
128	Another common effect is to mirror the image, so that the same edges touch:	148	Another common effect is to mirror the image, so that the same edges
		149	touch:
129		150
130	mirror load "$HOME/mypic.png"	151	mirror keep { load "$HOME/mypic.png" }
131		152
132	This is also a typical background expression:	153	Another common background expression is:
133		154
134	rootalign root	155	rootalign root
135		156
136	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
137	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
138	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:
139	moved around.	160	the image seems to be static while the window is moved around.
140		161
141	=head2 CYCLES AND CACHING	162	=head2 COLOUR SPECIFICATIONS
142		163
143	As has been mentioned before, the expression might be evaluated multiple	164	Whenever an oprator expects a "colour", then this can be specified in one
144	times. Each time the expression is reevaluated, a new cycle is said to	165	of two ways: Either as string with an X11 colour specification, such as:
145	have begun. Many operators cache their results till the next cycle.
146		166
147	For example, the C<load> operator keeps a copy of the image. If it is	167	"red" # named colour
148	asked to load the same image on the next cycle it will not load it again,	168	"#f00" # simple rgb
149	but return the cached copy.	169	"[50]red" # red with 50% alpha
		170	"TekHVC:300/50/50" # anything goes
150		171
151	This only works for one cycle though, so as long as you load the same	172	OR as an array reference with one, three or four components:
152	image every time, it will always be cached, but when you load a different
153	image, it will forget about the first one.
154		173
155	This allows you to either speed things up by keeping multiple images in	174	[0.5] # 50% gray, 100% alpha
156	memory, or comserve memory by loading images more often.	175	[0.5, 0, 0] # dark red, no green or blur, 100% alpha
		176	[0.5, 0, 0, 0.7] # same with explicit 70% alpha
157		177
158	For example, you can keep two images in memory and use a random one like	178	=head2 CACHING AND SENSITIVITY
159	this:
160		179
161	my $img1 = load "img1.png";	180	Since some operations (such as C<load> and C<blur>) can take a long time,
162	my $img2 = load "img2.png";	181	caching results can be very important for a smooth operation. Caching can
163	(0.5 > rand) ? $img1 : $img2	182	also be useful to reduce memory usage, though, for example, when an image
		183	is cached by C<load>, it could be shared by multiple terminal windows
		184	running inside urxvtd.
164		185
165	Since both images are "loaded" every time the expression is evaluated,	186	=head3 C<keep { ... }> caching
166	they are always kept in memory. Contrast this version:
167		187
168	my $path1 = "img1.png";	188	The most important way to cache expensive operations is to use C<keep {
169	my $path2 = "img2.png";	189	... }>. The C<keep> operator takes a block of multiple statements enclosed
170	load ((0.5 > rand) ? $path1 : $path2)	190	by C<{}> and keeps the return value in memory.
171		191
172	Here, a path is selected randomly, and load is only called for one image,	192	An expression can be "sensitive" to various external events, such as
173	so keeps only one image in memory. If, on the next evaluation, luck	193	scaling or moving the window, root background changes and timers. Simply
174	decides to use the other path, then it will have to load that image again.	194	using an expression (such as C<scale> without parameters) that depends on
		195	certain changing values (called "variables"), or using those variables
		196	directly, will make an expression sensitive to these events - for example,
		197	using C<scale> or C<TW> will make the expression sensitive to the terminal
		198	size, and thus to resizing events.
		199
		200	When such an event happens, C<keep> will automatically trigger a
		201	reevaluation of the whole expression with the new value of the expression.
		202
		203	C<keep> is most useful for expensive operations, such as C<blur>:
		204
		205	rootalign keep { blur 20, root }
		206
		207	This makes a blurred copy of the root background once, and on subsequent
		208	calls, just root-aligns it. Since C<blur> is usually quite slow and
		209	C<rootalign> is quite fast, this trades extra memory (for the cached
		210	blurred pixmap) with speed (blur only needs to be redone when root
		211	changes).
		212
		213	=head3 C<load> caching
		214
		215	The C<load> operator itself does not keep images in memory, but as long as
		216	the image is still in memory, C<load> will use the in-memory image instead
		217	of loading it freshly from disk.
		218
		219	That means that this expression:
		220
		221	keep { load "$HOME/path..." }
		222
		223	Not only caches the image in memory, other terminal instances that try to
		224	C<load> it can reuse that in-memory copy.
175		225
176	=head1 REFERENCE	226	=head1 REFERENCE
177		227
178	=head2 COMMAND LINE SWITCHES	228	=head2 COMMAND LINE SWITCHES
179		229
…		…
189	overwriting borders and any other areas, such as the scrollbar.	239	overwriting borders and any other areas, such as the scrollbar.
190		240
191	Specifying this flag changes the behaviour, so that the image only	241	Specifying this flag changes the behaviour, so that the image only
192	replaces the background of the character area.	242	replaces the background of the character area.
193		243
		244	=item --background-interval seconds
		245
		246	Since some operations in the underlying XRender extension can effectively
		247	freeze your X-server for prolonged time, this extension enforces a minimum
		248	time between updates, which is normally about 0.1 seconds.
		249
		250	If you want to do updates more often, you can decrease this safety
		251	interval with this switch.
		252
194	=back	253	=back
195		254
196	=cut	255	=cut
197		256
		257	our %_IMG_CACHE;
198	our $HOME;	258	our $HOME;
199	our ($self, $old, $new);	259	our ($self, $frame);
200	our ($x, $y, $w, $h);	260	our ($x, $y, $w, $h);
201		261
202	# enforce at least this interval between updates	262	# enforce at least this interval between updates
203	our $MIN_INTERVAL = 1/100;	263	our $MIN_INTERVAL = 6/59.951;
204		264
205	{	265	{
206	package urxvt::bgdsl; # background language	266	package urxvt::bgdsl; # background language
		267
		268	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
		269	sub FR_CACHE () { 1 } # cached values
		270	sub FR_AGAIN () { 2 } # what this expr is sensitive to
		271	sub FR_STATE () { 3 } # watchers etc.
207		272
208	use List::Util qw(min max sum shuffle);	273	use List::Util qw(min max sum shuffle);
209		274
210	=head2 PROVIDERS/GENERATORS	275	=head2 PROVIDERS/GENERATORS
211		276
…		…
218	=item load $path	283	=item load $path
219		284
220	Loads the image at the given C<$path>. The image is set to plane tiling	285	Loads the image at the given C<$path>. The image is set to plane tiling
221	mode.	286	mode.
222		287
223	Loaded images will be cached for one cycle.	288	If the image is already in memory (e.g. because another terminal instance
		289	uses it), then the in-memory copy us returned instead.
		290
		291	=item load_uc $path
		292
		293	Load uncached - same as load, but does not cache the image, which means it
		294	is I<always> loaded from the filesystem again.
224		295
225	=cut	296	=cut
226		297
227	sub load($) {	298	sub load($) {
228	my ($path) = @_;	299	my ($path) = @_;
229		300
230	$new->{load}{$path} = $old->{load}{$path} \|\| $self->new_img_from_file ($path);	301	$_IMG_CACHE{$path} \|\| do {
		302	my $img = $self->new_img_from_file ($path);
		303	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		304	$img
		305	}
231	}	306	}
232		307
233	=item root	308	=item root
234		309
235	Returns the root window pixmap, that is, hopefully, the background image	310	Returns the root window pixmap, that is, hopefully, the background image
236	of your screen. The image is set to extend mode.	311	of your screen.
237		312
238	This function makes your expression root sensitive, that means it will be	313	This function makes your expression root sensitive, that means it will be
239	reevaluated when the bg image changes.	314	reevaluated when the bg image changes.
240		315
241	=cut	316	=cut
242		317
243	sub root() {	318	sub root() {
244	$new->{rootpmap_sensitive} = 1;	319	$frame->[FR_AGAIN]{rootpmap} = 1;
245	die "root op not supported, exg, we need you";	320	$self->new_img_from_root
246	}	321	}
247		322
248	=item solid $colour	323	=item solid $colour
249		324
250	=item solid $width, $height, $colour	325	=item solid $width, $height, $colour
…		…
258	=cut	333	=cut
259		334
260	sub solid($;$$) {	335	sub solid($;$$) {
261	my $colour = pop;	336	my $colour = pop;
262		337
263	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	338	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
264	$img->fill ($colour);	339	$img->fill ($colour);
265	$img	340	$img
266	}	341	}
267		342
268	=back	343	=item clone $img
269		344
270	=head2 VARIABLES	345	Returns an exact copy of the image. This is useful if you want to have
		346	multiple copies of the same image to apply different effects to.
271		347
272	The following functions provide variable data such as the terminal window
273	dimensions. They are not (Perl-) variables, they jsut return stuff that
274	varies. Most of them make your expression sensitive to some events, for
275	example using C<TW> (terminal width) means your expression is evaluated
276	again when the terminal is resized.
277
278	=over 4
279
280	=item TX
281
282	=item TY
283
284	Return the X and Y coordinates of the terminal window (the terminal
285	window is the full window by default, and the character area only when in
286	border-respect mode).
287
288	Using these functions make your expression sensitive to window moves.
289
290	These functions are mainly useful to align images to the root window.
291
292	Example: load an image and align it so it looks as if anchored to the
293	background.
294
295	move -TX, -TY, load "mybg.png"
296
297	=item TW
298
299	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
300	terminal window is the full window by default, and the character area only
301	when in border-respect mode).
302
303	Using these functions make your expression sensitive to window resizes.
304
305	These functions are mainly useful to scale images, or to clip images to
306	the window size to conserve memory.
307
308	Example: take the screen background, clip it to the window size, blur it a
309	bit, align it to the window position and use it as background.
310
311	clip move -TX, -TY, blur 5, root
312
313	=cut	348	=cut
314		349
315	sub TX() { $new->{position_sensitive} = 1; $x }
316	sub TY() { $new->{position_sensitive} = 1; $y }
317	sub TW() { $new->{size_sensitive} = 1; $w }
318	sub TH() { $new->{size_sensitive} = 1; $h }
319
320	=item now
321
322	Returns the current time as (fractional) seconds since the epoch.
323
324	Using this expression does I<not> make your expression sensitive to time,
325	but the next two functions do.
326
327	=item again $seconds
328
329	When this function is used the expression will be reevaluated again in
330	C<$seconds> seconds.
331
332	Example: load some image and rotate it according to the time of day (as if it were
333	the hour pointer of a clock). Update this image every minute.
334
335	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
336
337	=item counter $seconds
338
339	Like C<again>, but also returns an increasing counter value, starting at
340	0, which might be useful for some simple animation effects.
341
342	=cut
343
344	sub now() { urxvt::NOW }
345
346	sub again($) {
347	$new->{again} = $_[0];
348	}
349
350	sub counter($) {	350	sub clone($) {
351	$new->{again} = $_[0];	351	$_[0]->clone
352	$self->{counter} + 0
353	}	352	}
354		353
355	=back	354	=item merge $img ...
		355
		356	Takes any number of images and merges them together, creating a single
		357	image containing them all. The tiling mode of the first image is used as
		358	the tiling mode of the resulting image.
		359
		360	This function is called automatically when an expression returns multiple
		361	images.
		362
		363	=cut
		364
		365	sub merge(@) {
		366	return $_[0] unless $#_;
		367
		368	# rather annoyingly clumsy, but optimisation is for another time
		369
		370	my $x0 = +1e9;
		371	my $y0 = +1e9;
		372	my $x1 = -1e9;
		373	my $y1 = -1e9;
		374
		375	for (@_) {
		376	my ($x, $y, $w, $h) = $_->geometry;
		377
		378	$x0 = $x if $x0 > $x;
		379	$y0 = $y if $y0 > $y;
		380
		381	$x += $w;
		382	$y += $h;
		383
		384	$x1 = $x if $x1 < $x;
		385	$y1 = $y if $y1 < $y;
		386	}
		387
		388	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		389	$base->repeat_mode ($_[0]->repeat_mode);
		390	$base->fill ([0, 0, 0, 0]);
		391
		392	$base->draw ($_)
		393	for @_;
		394
		395	$base
		396	}
356		397
357	=head2 TILING MODES	398	=head2 TILING MODES
358		399
359	The following operators modify the tiling mode of an image, that is, the	400	The following operators modify the tiling mode of an image, that is, the
360	way that pixels outside the image area are painted when the image is used.	401	way that pixels outside the image area are painted when the image is used.
…		…
390	become transparent. This mode is most useful when you want to place an	431	become transparent. This mode is most useful when you want to place an
391	image over another image or the background colour while leaving all	432	image over another image or the background colour while leaving all
392	background pixels outside the image unchanged.	433	background pixels outside the image unchanged.
393		434
394	Example: load an image and display it in the upper left corner. The rest	435	Example: load an image and display it in the upper left corner. The rest
395	of the space is left "empty" (transparent or wahtever your compisotr does	436	of the space is left "empty" (transparent or whatever your compositor does
396	in alpha mode, else background colour).	437	in alpha mode, else background colour).
397		438
398	pad load "mybg.png"	439	pad load "mybg.png"
399		440
400	=item extend $img	441	=item extend $img
401		442
402	Extends the image over the whole plane, using the closest pixel in the	443	Extends the image over the whole plane, using the closest pixel in the
403	area outside the image. This mode is mostly useful when you more complex	444	area outside the image. This mode is mostly useful when you use more complex
404	filtering operations and want the pixels outside the image to have the	445	filtering operations and want the pixels outside the image to have the
405	same values as the pixels near the edge.	446	same values as the pixels near the edge.
406		447
407	Example: just for curiosity, how does this pixel extension stuff work?	448	Example: just for curiosity, how does this pixel extension stuff work?
408		449
…		…
434	$img	475	$img
435	}	476	}
436		477
437	=back	478	=back
438		479
439	=head2 PIXEL OPERATORS	480	=head2 VARIABLE VALUES
440		481
441	The following operators modify the image pixels in various ways.	482	The following functions provide variable data such as the terminal window
		483	dimensions. They are not (Perl-) variables, they just return stuff that
		484	varies. Most of them make your expression sensitive to some events, for
		485	example using C<TW> (terminal width) means your expression is evaluated
		486	again when the terminal is resized.
442		487
443	=over 4	488	=over 4
444		489
445	=item clone $img	490	=item TX
446		491
447	Returns an exact copy of the image.	492	=item TY
448		493
449	=cut	494	Return the X and Y coordinates of the terminal window (the terminal
		495	window is the full window by default, and the character area only when in
		496	border-respect mode).
450		497
		498	Using these functions make your expression sensitive to window moves.
		499
		500	These functions are mainly useful to align images to the root window.
		501
		502	Example: load an image and align it so it looks as if anchored to the
		503	background (that's exactly what C<rootalign> does btw.):
		504
		505	move -TX, -TY, keep { load "mybg.png" }
		506
		507	=item TW
		508
		509	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		510	terminal window is the full window by default, and the character area only
		511	when in border-respect mode).
		512
		513	Using these functions make your expression sensitive to window resizes.
		514
		515	These functions are mainly useful to scale images, or to clip images to
		516	the window size to conserve memory.
		517
		518	Example: take the screen background, clip it to the window size, blur it a
		519	bit, align it to the window position and use it as background.
		520
		521	clip move -TX, -TY, keep { blur 5, root }
		522
		523	=cut
		524
		525	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
		526	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
		527	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
		528	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
		529
		530	=item now
		531
		532	Returns the current time as (fractional) seconds since the epoch.
		533
		534	Using this expression does I<not> make your expression sensitive to time,
		535	but the next two functions do.
		536
		537	=item again $seconds
		538
		539	When this function is used the expression will be reevaluated again in
		540	C<$seconds> seconds.
		541
		542	Example: load some image and rotate it according to the time of day (as if it were
		543	the hour pointer of a clock). Update this image every minute.
		544
		545	again 60;
		546	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
		547
		548	=item counter $seconds
		549
		550	Like C<again>, but also returns an increasing counter value, starting at
		551	0, which might be useful for some simple animation effects.
		552
		553	=cut
		554
		555	sub now() { urxvt::NOW }
		556
		557	sub again($) {
		558	$frame->[FR_AGAIN]{time} = $_[0];
		559	}
		560
451	sub clone($) {	561	sub counter($) {
452	$_[0]->clone	562	$frame->[FR_AGAIN]{time} = $_[0];
		563	$frame->[FR_STATE]{counter} + 0
453	}	564	}
		565
		566	=back
		567
		568	=head2 SHAPE CHANGING OPERATORS
		569
		570	The following operators modify the shape, size or position of the image.
		571
		572	=over 4
454		573
455	=item clip $img	574	=item clip $img
456		575
457	=item clip $width, $height, $img	576	=item clip $width, $height, $img
458		577
…		…
469	assumed.	588	assumed.
470		589
471	Example: load an image, blur it, and clip it to the window size to save	590	Example: load an image, blur it, and clip it to the window size to save
472	memory.	591	memory.
473		592
474	clip blur 10, load "mybg.png"	593	clip keep { blur 10, load "mybg.png" }
475		594
476	=cut	595	=cut
477		596
478	sub clip($;$$;$$) {	597	sub clip($;$$;$$) {
479	my $img = pop;	598	my $img = pop;
…		…
552		671
553	Example: move the image right by 20 pixels and down by 30.	672	Example: move the image right by 20 pixels and down by 30.
554		673
555	move 20, 30, ...	674	move 20, 30, ...
556		675
		676	=item align $xalign, $yalign, $img
		677
		678	Aligns the image according to a factor - C<0> means the image is moved to
		679	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		680	exactly centered and C<1> means it touches the right or bottom edge.
		681
		682	Example: remove any visible border around an image, center it vertically but move
		683	it to the right hand side.
		684
		685	align 1, 0.5, pad $img
		686
557	=item center $img	687	=item center $img
558		688
559	=item center $width, $height, $img	689	=item center $width, $height, $img
560		690
561	Centers the image, i.e. the center of the image is moved to the center of	691	Centers the image, i.e. the center of the image is moved to the center of
562	the terminal window (or the box specified by C<$width> and C<$height> if	692	the terminal window (or the box specified by C<$width> and C<$height> if
563	given).	693	given).
		694
		695	Example: load an image and center it.
		696
		697	center keep { pad load "mybg.png" }
564		698
565	=item rootalign $img	699	=item rootalign $img
566		700
567	Moves the image so that it appears glued to the screen as opposed to the	701	Moves the image so that it appears glued to the screen as opposed to the
568	window. This gives the illusion of a larger area behind the window. It is	702	window. This gives the illusion of a larger area behind the window. It is
569	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	703	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
570	top left of the screen.	704	top left of the screen.
571		705
572	Example: load a background image, put it in mirror mode and root align it.	706	Example: load a background image, put it in mirror mode and root align it.
573		707
574	rootalign mirror load "mybg.png"	708	rootalign keep { mirror load "mybg.png" }
575		709
576	Example: take the screen background and align it, giving the illusion of	710	Example: take the screen background and align it, giving the illusion of
577	transparency as long as the window isn't in front of other windows.	711	transparency as long as the window isn't in front of other windows.
578		712
579	rootalign root	713	rootalign root
580		714
581	=cut	715	=cut
582		716
583	sub move($$;$) {	717	sub move($$;$) {
584	my $img = pop->clone;	718	my $img = pop->clone;
585	$img->move ($_[0], $_[1]);	719	$img->move ($_[0], $_[1]);
586	$img	720	$img
587	}	721	}
588		722
		723	sub align($;$$) {
		724	my $img = pop;
		725
		726	move $_[0] * (TW - $img->w),
		727	$_[1] * (TH - $img->h),
		728	$img
		729	}
		730
589	sub center($;$$) {	731	sub center($;$$) {
590	my $img = pop;	732	my $img = pop;
591	my $w = $_[0] \|\| TW;	733	my $w = $_[0] \|\| TW;
592	my $h = $_[0] \|\| TH;	734	my $h = $_[1] \|\| TH;
593		735
594	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img	736	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
595	}	737	}
596		738
597	sub rootalign($) {	739	sub rootalign($) {
598	move -TX, -TY, $_[0]	740	move -TX, -TY, $_[0]
599	}	741	}
600		742
		743	=item rotate $center_x, $center_y, $degrees, $img
		744
		745	Rotates the image clockwise by C<$degrees> degrees, around the point at
		746	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		747
		748	Example: rotate the image by 90 degrees around it's center.
		749
		750	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		751
		752	=cut
		753
		754	sub rotate($$$$) {
		755	my $img = pop;
		756	$img->rotate (
		757	$_[0] * ($img->w + $img->x),
		758	$_[1] * ($img->h + $img->y),
		759	$_[2] * (3.14159265 / 180),
		760	)
		761	}
		762
		763	=back
		764
		765	=head2 COLOUR MODIFICATIONS
		766
		767	The following operators change the pixels of the image.
		768
		769	=over 4
		770
		771	=item tint $color, $img
		772
		773	Tints the image in the given colour.
		774
		775	Example: tint the image red.
		776
		777	tint "red", load "rgb.png"
		778
		779	Example: the same, but specify the colour by component.
		780
		781	tint [1, 0, 0], load "rgb.png"
		782
		783	=cut
		784
		785	sub tint($$) {
		786	$_[1]->tint ($_[0])
		787	}
		788
601	=item contrast $factor, $img	789	=item contrast $factor, $img
602		790
603	=item contrast $r, $g, $b, $img	791	=item contrast $r, $g, $b, $img
604		792
605	=item contrast $r, $g, $b, $a, $img	793	=item contrast $r, $g, $b, $a, $img
606		794
607	Adjusts the I<contrast> of an image.	795	Adjusts the I<contrast> of an image.
608		796
609	#TODO#	797	The first form applies a single C<$factor> to red, green and blue, the
		798	second form applies separate factors to each colour channel, and the last
		799	form includes the alpha channel.
610		800
		801	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		802	contrast.
		803
		804	Due to limitations in the underlying XRender extension, lowering contrast
		805	also reduces brightness, while increasing contrast currently also
		806	increases brightness.
		807
611	=item brightness $factor, $img	808	=item brightness $bias, $img
612		809
613	=item brightness $r, $g, $b, $img	810	=item brightness $r, $g, $b, $img
614		811
615	=item brightness $r, $g, $b, $a, $img	812	=item brightness $r, $g, $b, $a, $img
616		813
617	Adjusts the brightness of an image.	814	Adjusts the brightness of an image.
		815
		816	The first form applies a single C<$bias> to red, green and blue, the
		817	second form applies separate biases to each colour channel, and the last
		818	form includes the alpha channel.
		819
		820	Values less than 0 reduce brightness, while values larger than 0 increase
		821	it. Useful range is from -1 to 1 - the former results in a black, the
		822	latter in a white picture.
		823
		824	Due to idiosyncrasies in the underlying XRender extension, biases less
		825	than zero can be I<very> slow.
618		826
619	=cut	827	=cut
620		828
621	sub contrast($$;$$;$) {	829	sub contrast($$;$$;$) {
622	my $img = pop;	830	my $img = pop;
623	my ($r, $g, $b, $a) = @_;	831	my ($r, $g, $b, $a) = @_;
624		832
625	($g, $b) = ($r, $r) if @_ < 4;	833	($g, $b) = ($r, $r) if @_ < 3;
626	$a = 1 if @_ < 5;	834	$a = 1 if @_ < 4;
627		835
628	$img = $img->clone;	836	$img = $img->clone;
629	$img->contrast ($r, $g, $b, $a);	837	$img->contrast ($r, $g, $b, $a);
630	$img	838	$img
631	}	839	}
632		840
633	sub brightness($$;$$;$) {	841	sub brightness($$;$$;$) {
634	my $img = pop;	842	my $img = pop;
635	my ($r, $g, $b, $a) = @_;	843	my ($r, $g, $b, $a) = @_;
636		844
637	($g, $b) = ($r, $r) if @_ < 4;	845	($g, $b) = ($r, $r) if @_ < 3;
638	$a = 1 if @_ < 5;	846	$a = 1 if @_ < 4;
639		847
640	$img = $img->clone;	848	$img = $img->clone;
641	$img->brightness ($r, $g, $b, $a);	849	$img->brightness ($r, $g, $b, $a);
642	$img	850	$img
643	}	851	}
…		…
659	sub blur($$;$) {	867	sub blur($$;$) {
660	my $img = pop;	868	my $img = pop;
661	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	869	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
662	}	870	}
663		871
664	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
665
666	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
667	pointer at C<$center_x> and C<$center_y> (specified as factor of image
668	width/height), generating a new image with width C<$new_width> and height
669	C<$new_height>.
670
671	#TODO# new width, height, maybe more operators?
672
673	Example: rotate the image by 90 degrees
674
675	=cut
676
677	sub rotate($$$$$$) {
678	my $img = pop;
679	$img->rotate (
680	$_[0],
681	$_[1],
682	$_[2] * $img->w,
683	$_[3] * $img->h,
684	$_[4] * (3.14159265 / 180),
685	)
686	}
687
688	=back	872	=back
689		873
		874	=head2 OTHER STUFF
		875
		876	Anything that didn't fit any of the other categories, even after applying
		877	force and closing our eyes.
		878
		879	=over 4
		880
		881	=item keep { ... }
		882
		883	This operator takes a code block as argument, that is, one or more
		884	statements enclosed by braces.
		885
		886	The trick is that this code block is only evaluated when the outcome
		887	changes - on other calls the C<keep> simply returns the image it computed
		888	previously (yes, it should only be used with images). Or in other words,
		889	C<keep> I<caches> the result of the code block so it doesn't need to be
		890	computed again.
		891
		892	This can be extremely useful to avoid redoing slow operations - for
		893	example, if your background expression takes the root background, blurs it
		894	and then root-aligns it it would have to blur the root background on every
		895	window move or resize.
		896
		897	Another example is C<load>, which can be quite slow.
		898
		899	In fact, urxvt itself encloses the whole expression in some kind of
		900	C<keep> block so it only is reevaluated as required.
		901
		902	Putting the blur into a C<keep> block will make sure the blur is only done
		903	once, while the C<rootalign> is still done each time the window moves.
		904
		905	rootlign keep { blur 10, root }
		906
		907	This leaves the question of how to force reevaluation of the block,
		908	in case the root background changes: If expression inside the block
		909	is sensitive to some event (root background changes, window geometry
		910	changes), then it will be reevaluated automatically as needed.
		911
		912	=cut
		913
		914	sub keep(&) {
		915	my $id = $_[0]+0;
		916
		917	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		918
		919	unless ($frame->[FR_CACHE]) {
		920	$frame->[FR_CACHE] = [ $_[0]() ];
		921
		922	my $self = $self;
		923	my $frame = $frame;
		924	Scalar::Util::weaken $frame;
		925	$self->compile_frame ($frame, sub {
		926	# clear this frame cache, also for all parents
		927	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		928	undef $frame->[FR_CACHE];
		929	}
		930
		931	$self->recalculate;
		932	});
		933	};
		934
		935	# in scalar context we always return the first original result, which
		936	# is not quite how perl works.
		937	wantarray
		938	? @{ $frame->[FR_CACHE] }
		939	: $frame->[FR_CACHE][0]
		940	}
		941
		942	# sub keep_clear() {
		943	# delete $self->{frame_cache};
		944	# }
		945
		946	=back
		947
690	=cut	948	=cut
691		949
692	}	950	}
693		951
694	sub parse_expr {	952	sub parse_expr {
695	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	953	my $expr = eval
		954	"sub {\n"
		955	. "package urxvt::bgdsl;\n"
		956	. "#line 0 'background expression'\n"
		957	. "$_[0]\n"
		958	. "}";
696	die if $@;	959	die if $@;
697	$expr	960	$expr
698	}	961	}
699		962
700	# compiles a parsed expression	963	# compiles a parsed expression
701	sub set_expr {	964	sub set_expr {
702	my ($self, $expr) = @_;	965	my ($self, $expr) = @_;
703		966
		967	$self->{root} = [];
704	$self->{expr} = $expr;	968	$self->{expr} = $expr;
705	$self->recalculate;	969	$self->recalculate;
		970	}
		971
		972	# takes a hash of sensitivity indicators and installs watchers
		973	sub compile_frame {
		974	my ($self, $frame, $cb) = @_;
		975
		976	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		977	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		978
		979	# don't keep stuff alive
		980	Scalar::Util::weaken $state;
		981
		982	if ($again->{nested}) {
		983	$state->{nested} = 1;
		984	} else {
		985	delete $state->{nested};
		986	}
		987
		988	if (my $interval = $again->{time}) {
		989	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		990	if $state->{time}[0] != $interval;
		991
		992	# callback might have changed, although we could just rule that out
		993	$state->{time}[1]->cb (sub {
		994	++$state->{counter};
		995	$cb->();
		996	});
		997	} else {
		998	delete $state->{time};
		999	}
		1000
		1001	if ($again->{position}) {
		1002	$state->{position} = $self->on (position_change => $cb);
		1003	} else {
		1004	delete $state->{position};
		1005	}
		1006
		1007	if ($again->{size}) {
		1008	$state->{size} = $self->on (size_change => $cb);
		1009	} else {
		1010	delete $state->{size};
		1011	}
		1012
		1013	if ($again->{rootpmap}) {
		1014	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		1015	} else {
		1016	delete $state->{rootpmap};
		1017	}
706	}	1018	}
707		1019
708	# evaluate the current bg expression	1020	# evaluate the current bg expression
709	sub recalculate {	1021	sub recalculate {
710	my ($arg_self) = @_;	1022	my ($arg_self) = @_;
…		…
720		1032
721	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1033	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
722		1034
723	# set environment to evaluate user expression	1035	# set environment to evaluate user expression
724		1036
725	local $self = $arg_self;	1037	local $self = $arg_self;
726
727	local $HOME = $ENV{HOME};	1038	local $HOME = $ENV{HOME};
728	local $old = $self->{state};	1039	local $frame = [];
729	local $new = my $state = $self->{state} = {};
730		1040
731	($x, $y, $w, $h) =
732	$self->background_geometry ($self->{border});	1041	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
733		1042
734	# evaluate user expression	1043	# evaluate user expression
735		1044
736	my $img = eval { $self->{expr}->() };	1045	my @img = eval { $self->{expr}->() };
737	warn $@ if $@;#d#	1046	die $@ if $@;
		1047	die "background-expr did not return anything.\n" unless @img;
		1048	die "background-expr: expected image(s), got something else.\n"
738	die if !UNIVERSAL::isa $img, "urxvt::img";	1049	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
739		1050
740	$state->{size_sensitive} = 1	1051	my $img = urxvt::bgdsl::merge @img;
		1052
		1053	$frame->[FR_AGAIN]{size} = 1
741	if $img->repeat_mode != urxvt::RepeatNormal;	1054	if $img->repeat_mode != urxvt::RepeatNormal;
742		1055
743	# if the expression is sensitive to external events, prepare reevaluation then	1056	# if the expression is sensitive to external events, prepare reevaluation then
744		1057	$self->compile_frame ($frame, sub { $arg_self->recalculate });
745	my $repeat;
746
747	if (my $again = $state->{again}) {
748	$repeat = 1;
749	my $self = $self;
750	$state->{timer} = $again == $old->{again}
751	? $old->{timer}
752	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
753	++$self->{counter};
754	$self->recalculate
755	});
756	}
757
758	if (delete $state->{position_sensitive}) {
759	$repeat = 1;
760	$self->enable (position_change => sub { $_[0]->recalculate });
761	} else {
762	$self->disable ("position_change");
763	}
764
765	if (delete $state->{size_sensitive}) {
766	$repeat = 1;
767	$self->enable (size_change => sub { $_[0]->recalculate });
768	} else {
769	$self->disable ("size_change");
770	}
771
772	if (delete $state->{rootpmap_sensitive}) {
773	$repeat = 1;
774	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
775	} else {
776	$self->disable ("rootpmap_change");
777	}
778		1058
779	# clear stuff we no longer need	1059	# clear stuff we no longer need
780		1060
781	%$old = ();	1061	# unless (%{ $frame->[FR_STATE] }) {
782
783	unless ($repeat) {
784	delete $self->{state};	1062	# delete $self->{state};
785	delete $self->{expr};	1063	# delete $self->{expr};
786	}	1064	# }
787		1065
788	# set background pixmap	1066	# set background pixmap
789		1067
790	$self->set_background ($img, $self->{border});	1068	$self->set_background ($img, $self->{border});
791	$self->scr_recolour (0);	1069	$self->scr_recolour (0);
…		…
793	}	1071	}
794		1072
795	sub on_start {	1073	sub on_start {
796	my ($self) = @_;	1074	my ($self) = @_;
797		1075
798	my $expr = $self->x_resource ("background.expr")	1076	my $expr = $self->x_resource ("%.expr")
799	or return;	1077	or return;
800		1078
		1079	$self->has_render
		1080	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1081
801	$self->set_expr (parse_expr $expr);	1082	$self->set_expr (parse_expr $expr);
802	$self->{border} = $self->x_resource_boolean ("background.border");	1083	$self->{border} = $self->x_resource_boolean ("%.border");
		1084
		1085	$MIN_INTERVAL = $self->x_resource ("%.interval");
803		1086
804	()	1087	()
805	}	1088	}
806		1089

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.44 by root, Sun Jun 10 11:31:22 2012 UTC vs. Revision 1.71 by root, Mon Jul 2 01:40:41 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.44 by root, Sun Jun 10 11:31:22 2012 UTC vs.
Revision 1.71 by root, Mon Jul 2 01:40:41 2012 UTC