[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 1.88 by root, Sat May 17 13:38:23 2014 UTC

…		…
1	#! perl	1	#! perl
2		2
3	#:META:X_RESOURCE:%.expr:string:background expression	3	#:META:RESOURCE:%.expr:string:background expression
4	#:META:X_RESOURCE:%.border.:boolean:respect the terminal border	4	#:META:RESOURCE:%.border:boolean:respect the terminal border
5		5	#:META: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
		17	=head1 QUICK AND DIRTY CHEAT SHEET
		18
		19	Just load a random jpeg image and tile the background with it without
		20	scaling or anything else:
		21
		22	load "/path/to/img.jpg"
		23
		24	The same, but use mirroring/reflection instead of tiling:
		25
		26	mirror load "/path/to/img.jpg"
		27
		28	Load an image and scale it to exactly fill the terminal window:
		29
		30	scale keep { load "/path/to/img.jpg" }
		31
		32	Implement pseudo-transparency by using a suitably-aligned root pixmap
		33	as window background:
		34
		35	rootalign root
		36
		37	Likewise, but keep a blurred copy:
		38
		39	rootalign keep { blur 10, root }
16		40
17	=head1 DESCRIPTION	41	=head1 DESCRIPTION
18		42
19	This extension manages the terminal background by creating a picture that	43	This extension manages the terminal background by creating a picture that
20	is behind the text, replacing the normal background colour.	44	is behind the text, replacing the normal background colour.
26	to be as simple as possible.	50	to be as simple as possible.
27		51
28	For example, to load an image and scale it to the window size, you would	52	For example, to load an image and scale it to the window size, you would
29	use:	53	use:
30		54
31	urxvt --background-expr 'scale load "/path/to/mybg.png"'	55	urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
32		56
33	Or specified as a X resource:	57	Or specified as a X resource:
34		58
35	URxvt.background-expr: scale load "/path/to/mybg.png"	59	URxvt.background-expr: scale keep { load "/path/to/mybg.png" }
36		60
37	=head1 THEORY OF OPERATION	61	=head1 THEORY OF OPERATION
38		62
39	At startup, just before the window is mapped for the first time, the	63	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	64	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	77	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	78	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	79	pixmap is replaced by another one the root background changes; or when the
56	timer elapses), then the expression will be evaluated again.	80	timer elapses), then the expression will be evaluated again.
57		81
58	For example, an expression such as C<scale load "$HOME/mybg.png"> scales the	82	For example, an expression such as C<scale keep { load "$HOME/mybg.png"
59	image to the window size, so it relies on the window size and will	83	}> 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	84	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	85	example. That ensures that the picture always fills the terminal, even
62	after it's size changes.	86	after its size changes.
63		87
64	=head2 EXPRESSIONS	88	=head2 EXPRESSIONS
65		89
66	Expressions are normal Perl expressions, in fact, they are Perl blocks -	90	Expressions are normal Perl expressions, in fact, they are Perl blocks -
67	which means you could use multiple lines and statements:	91	which means you could use multiple lines and statements:
68		92
		93	scale keep {
69	again 3600;	94	again 3600;
70	if (localtime now)[6]) {	95	if (localtime now)[6]) {
71	return scale load "$HOME/weekday.png";	96	return load "$HOME/weekday.png";
72	} else {	97	} else {
73	return scale load "$HOME/sunday.png";	98	return load "$HOME/sunday.png";
		99	}
74	}	100	}
75		101
76	This expression gets evaluated once per hour. It will set F<sunday.png> as	102	This inner expression is evaluated once per hour (and whenever the
		103	terminal window is resized). It sets F<sunday.png> as background on
77	background on Sundays, and F<weekday.png> on all other days.	104	Sundays, and F<weekday.png> on all other days.
78		105
79	Fortunately, we expect that most expressions will be much simpler, with	106	Fortunately, we expect that most expressions will be much simpler, with
80	little Perl knowledge needed.	107	little Perl knowledge needed.
81		108
82	Basically, you always start with a function that "generates" an image	109	Basically, you always start with a function that "generates" an image
…		…
115	horizontal and vertical dimensions. For example, this halves the image	142	horizontal and vertical dimensions. For example, this halves the image
116	width and doubles the image height:	143	width and doubles the image height:
117		144
118	scale 0.5, 2, load "$HOME/mypic.png"	145	scale 0.5, 2, load "$HOME/mypic.png"
119		146
120	Other effects than scalign are also readily available, for exmaple, you can	147	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:	148	because each time the terminal is resized, it loads the PNG image again
		149	and scales it. Scaling is usually fast (and unavoidable), but loading the
		150	image can be quite time consuming. This is where C<keep> comes in handy:
122		151
		152	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		153
		154	The C<keep> operator executes all the statements inside the braces only
		155	once, or when it thinks the outcome might change. In other cases it
		156	returns the last value computed by the brace block.
		157
		158	This means that the C<load> is only executed once, which makes it much
		159	faster, but also means that more memory is being used, because the loaded
		160	image must be kept in memory at all times. In this expression, the
		161	trade-off is likely worth it.
		162
		163	But back to effects: Other effects than scaling are also readily
		164	available, for example, you can tile the image to fill the whole window,
		165	instead of resizing it:
		166
123	tile load "$HOME/mypic.png"	167	tile keep { load "$HOME/mypic.png" }
124		168
125	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator	169	In fact, images returned by C<load> are in C<tile> mode by default, so the
126	is kind of superfluous.	170	C<tile> operator is kind of superfluous.
127		171
128	Another common effect is to mirror the image, so that the same edges touch:	172	Another common effect is to mirror the image, so that the same edges
		173	touch:
129		174
130	mirror load "$HOME/mypic.png"	175	mirror keep { load "$HOME/mypic.png" }
131		176
132	This is also a typical background expression:	177	Another common background expression is:
133		178
134	rootalign root	179	rootalign root
135		180
136	It first takes a snapshot of the screen background image, and then	181	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	182	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	183	left corner of the terminal window)- the result is pseudo-transparency:
139	moved around.	184	the image seems to be static while the window is moved around.
140		185
141	=head2 CYCLES AND CACHING	186	=head2 COLOUR SPECIFICATIONS
142		187
143	As has been mentioned before, the expression might be evaluated multiple	188	Whenever an operator expects a "colour", then this can be specified in one
144	times. Each time the expression is reevaluated, a new cycle is said to	189	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		190
147	For example, the C<load> operator keeps a copy of the image. If it is	191	"red" # named colour
148	asked to load the same image on the next cycle it will not load it again,	192	"#f00" # simple rgb
149	but return the cached copy.	193	"[50]red" # red with 50% alpha
		194	"TekHVC:300/50/50" # anything goes
150		195
151	This only works for one cycle though, so as long as you load the same	196	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		197
155	This allows you to either speed things up by keeping multiple images in	198	[0.5] # 50% gray, 100% alpha
156	memory, or comserve memory by loading images more often.	199	[0.5, 0, 0] # dark red, no green or blur, 100% alpha
		200	[0.5, 0, 0, 0.7] # same with explicit 70% alpha
157		201
158	For example, you can keep two images in memory and use a random one like	202	=head2 CACHING AND SENSITIVITY
159	this:
160		203
161	my $img1 = load "img1.png";	204	Since some operations (such as C<load> and C<blur>) can take a long time,
162	my $img2 = load "img2.png";	205	caching results can be very important for a smooth operation. Caching can
163	(0.5 > rand) ? $img1 : $img2	206	also be useful to reduce memory usage, though, for example, when an image
		207	is cached by C<load>, it could be shared by multiple terminal windows
		208	running inside urxvtd.
164		209
165	Since both images are "loaded" every time the expression is evaluated,	210	=head3 C<keep { ... }> caching
166	they are always kept in memory. Contrast this version:
167		211
168	my $path1 = "img1.png";	212	The most important way to cache expensive operations is to use C<keep {
169	my $path2 = "img2.png";	213	... }>. The C<keep> operator takes a block of multiple statements enclosed
170	load ((0.5 > rand) ? $path1 : $path2)	214	by C<{}> and keeps the return value in memory.
171		215
172	Here, a path is selected randomly, and load is only called for one image,	216	An expression can be "sensitive" to various external events, such as
173	so keeps only one image in memory. If, on the next evaluation, luck	217	scaling or moving the window, root background changes and timers. Simply
174	decides to use the other path, then it will have to load that image again.	218	using an expression (such as C<scale> without parameters) that depends on
		219	certain changing values (called "variables"), or using those variables
		220	directly, will make an expression sensitive to these events - for example,
		221	using C<scale> or C<TW> will make the expression sensitive to the terminal
		222	size, and thus to resizing events.
		223
		224	When such an event happens, C<keep> will automatically trigger a
		225	reevaluation of the whole expression with the new value of the expression.
		226
		227	C<keep> is most useful for expensive operations, such as C<blur>:
		228
		229	rootalign keep { blur 20, root }
		230
		231	This makes a blurred copy of the root background once, and on subsequent
		232	calls, just root-aligns it. Since C<blur> is usually quite slow and
		233	C<rootalign> is quite fast, this trades extra memory (for the cached
		234	blurred pixmap) with speed (blur only needs to be redone when root
		235	changes).
		236
		237	=head3 C<load> caching
		238
		239	The C<load> operator itself does not keep images in memory, but as long as
		240	the image is still in memory, C<load> will use the in-memory image instead
		241	of loading it freshly from disk.
		242
		243	That means that this expression:
		244
		245	keep { load "$HOME/path..." }
		246
		247	Not only caches the image in memory, other terminal instances that try to
		248	C<load> it can reuse that in-memory copy.
175		249
176	=head1 REFERENCE	250	=head1 REFERENCE
177		251
178	=head2 COMMAND LINE SWITCHES	252	=head2 COMMAND LINE SWITCHES
179		253
…		…
189	overwriting borders and any other areas, such as the scrollbar.	263	overwriting borders and any other areas, such as the scrollbar.
190		264
191	Specifying this flag changes the behaviour, so that the image only	265	Specifying this flag changes the behaviour, so that the image only
192	replaces the background of the character area.	266	replaces the background of the character area.
193		267
		268	=item --background-interval seconds
		269
		270	Since some operations in the underlying XRender extension can effectively
		271	freeze your X-server for prolonged time, this extension enforces a minimum
		272	time between updates, which is normally about 0.1 seconds.
		273
		274	If you want to do updates more often, you can decrease this safety
		275	interval with this switch.
		276
194	=back	277	=back
195		278
196	=cut	279	=cut
197		280
		281	our %_IMG_CACHE;
198	our $HOME;	282	our $HOME;
199	our ($self, $old, $new);	283	our ($self, $frame);
200	our ($x, $y, $w, $h);	284	our ($x, $y, $w, $h, $focus);
201		285
202	# enforce at least this interval between updates	286	# enforce at least this interval between updates
203	our $MIN_INTERVAL = 1/100;	287	our $MIN_INTERVAL = 6/59.951;
204		288
205	{	289	{
206	package urxvt::bgdsl; # background language	290	package urxvt::bgdsl; # background language
		291
		292	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
		293	sub FR_CACHE () { 1 } # cached values
		294	sub FR_AGAIN () { 2 } # what this expr is sensitive to
		295	sub FR_STATE () { 3 } # watchers etc.
207		296
208	use List::Util qw(min max sum shuffle);	297	use List::Util qw(min max sum shuffle);
209		298
210	=head2 PROVIDERS/GENERATORS	299	=head2 PROVIDERS/GENERATORS
211		300
…		…
218	=item load $path	307	=item load $path
219		308
220	Loads the image at the given C<$path>. The image is set to plane tiling	309	Loads the image at the given C<$path>. The image is set to plane tiling
221	mode.	310	mode.
222		311
223	Loaded images will be cached for one cycle.	312	If the image is already in memory (e.g. because another terminal instance
		313	uses it), then the in-memory copy is returned instead.
224		314
		315	=item load_uc $path
		316
		317	Load uncached - same as load, but does not cache the image, which means it
		318	is I<always> loaded from the filesystem again, even if another copy of it
		319	is in memory at the time.
		320
225	=cut	321	=cut
		322
		323	sub load_uc($) {
		324	$self->new_img_from_file ($_[0])
		325	}
226		326
227	sub load($) {	327	sub load($) {
228	my ($path) = @_;	328	my ($path) = @_;
229		329
230	$new->{load}{$path} = $old->{load}{$path} \|\| $self->new_img_from_file ($path);	330	$_IMG_CACHE{$path} \|\| do {
		331	my $img = load_uc $path;
		332	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		333	$img
		334	}
231	}	335	}
232		336
233	=item root	337	=item root
234		338
235	Returns the root window pixmap, that is, hopefully, the background image	339	Returns the root window pixmap, that is, hopefully, the background image
236	of your screen. The image is set to extend mode.	340	of your screen.
237		341
238	This function makes your expression root sensitive, that means it will be	342	This function makes your expression root sensitive, that means it will be
239	reevaluated when the bg image changes.	343	reevaluated when the bg image changes.
240		344
241	=cut	345	=cut
242		346
243	sub root() {	347	sub root() {
244	$new->{rootpmap_sensitive} = 1;	348	$frame->[FR_AGAIN]{rootpmap} = 1;
245	die "root op not supported, exg, we need you";	349	$self->new_img_from_root
246	}	350	}
247		351
248	=item solid $colour	352	=item solid $colour
249		353
250	=item solid $width, $height, $colour	354	=item solid $width, $height, $colour
…		…
258	=cut	362	=cut
259		363
260	sub solid($;$$) {	364	sub solid($;$$) {
261	my $colour = pop;	365	my $colour = pop;
262		366
263	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	367	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
264	$img->fill ($colour);	368	$img->fill ($colour);
265	$img	369	$img
266	}	370	}
267		371
268	=back	372	=item clone $img
269		373
270	=head2 VARIABLES	374	Returns an exact copy of the image. This is useful if you want to have
		375	multiple copies of the same image to apply different effects to.
271		376
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	377	=cut
314		378
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} = $_[0];
348	}
349
350	sub counter($) {	379	sub clone($) {
351	$new->{again} = $_[0];	380	$_[0]->clone
352	$self->{counter} + 0	381	}
		382
		383	=item merge $img ...
		384
		385	Takes any number of images and merges them together, creating a single
		386	image containing them all. The tiling mode of the first image is used as
		387	the tiling mode of the resulting image.
		388
		389	This function is called automatically when an expression returns multiple
		390	images.
		391
		392	=cut
		393
		394	sub merge(@) {
		395	return $_[0] unless $#_;
		396
		397	# rather annoyingly clumsy, but optimisation is for another time
		398
		399	my $x0 = +1e9;
		400	my $y0 = +1e9;
		401	my $x1 = -1e9;
		402	my $y1 = -1e9;
		403
		404	for (@_) {
		405	my ($x, $y, $w, $h) = $_->geometry;
		406
		407	$x0 = $x if $x0 > $x;
		408	$y0 = $y if $y0 > $y;
		409
		410	$x += $w;
		411	$y += $h;
		412
		413	$x1 = $x if $x1 < $x;
		414	$y1 = $y if $y1 < $y;
		415	}
		416
		417	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		418	$base->repeat_mode ($_[0]->repeat_mode);
		419	$base->fill ([0, 0, 0, 0]);
		420
		421	$base->draw ($_)
		422	for @_;
		423
		424	$base
353	}	425	}
354		426
355	=back	427	=back
356		428
357	=head2 TILING MODES	429	=head2 TILING MODES
…		…
390	become transparent. This mode is most useful when you want to place an	462	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	463	image over another image or the background colour while leaving all
392	background pixels outside the image unchanged.	464	background pixels outside the image unchanged.
393		465
394	Example: load an image and display it in the upper left corner. The rest	466	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	467	of the space is left "empty" (transparent or whatever your compositor does
396	in alpha mode, else background colour).	468	in alpha mode, else background colour).
397		469
398	pad load "mybg.png"	470	pad load "mybg.png"
399		471
400	=item extend $img	472	=item extend $img
401		473
402	Extends the image over the whole plane, using the closest pixel in the	474	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	475	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	476	filtering operations and want the pixels outside the image to have the
405	same values as the pixels near the edge.	477	same values as the pixels near the edge.
406		478
407	Example: just for curiosity, how does this pixel extension stuff work?	479	Example: just for curiosity, how does this pixel extension stuff work?
408		480
…		…
434	$img	506	$img
435	}	507	}
436		508
437	=back	509	=back
438		510
439	=head2 PIXEL OPERATORS	511	=head2 VARIABLE VALUES
440		512
441	The following operators modify the image pixels in various ways.	513	The following functions provide variable data such as the terminal window
		514	dimensions. They are not (Perl-) variables, they just return stuff that
		515	varies. Most of them make your expression sensitive to some events, for
		516	example using C<TW> (terminal width) means your expression is evaluated
		517	again when the terminal is resized.
442		518
443	=over 4	519	=over 4
444		520
445	=item clone $img	521	=item TX
446		522
447	Returns an exact copy of the image.	523	=item TY
448		524
449	=cut	525	Return the X and Y coordinates of the terminal window (the terminal
		526	window is the full window by default, and the character area only when in
		527	border-respect mode).
450		528
		529	Using these functions makes your expression sensitive to window moves.
		530
		531	These functions are mainly useful to align images to the root window.
		532
		533	Example: load an image and align it so it looks as if anchored to the
		534	background (that's exactly what C<rootalign> does btw.):
		535
		536	move -TX, -TY, keep { load "mybg.png" }
		537
		538	=item TW
		539
		540	=item TH
		541
		542	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		543	terminal window is the full window by default, and the character area only
		544	when in border-respect mode).
		545
		546	Using these functions makes your expression sensitive to window resizes.
		547
		548	These functions are mainly useful to scale images, or to clip images to
		549	the window size to conserve memory.
		550
		551	Example: take the screen background, clip it to the window size, blur it a
		552	bit, align it to the window position and use it as background.
		553
		554	clip move -TX, -TY, keep { blur 5, root }
		555
		556	=item FOCUS
		557
		558	Returns a boolean indicating whether the terminal window has keyboard
		559	focus, in which case it returns true.
		560
		561	Using this function makes your expression sensitive to focus changes.
		562
		563	A common use case is to fade the background image when the terminal loses
		564	focus, often together with the C<-fade> command line option. In fact,
		565	there is a special function for just that use case: C<focus_fade>.
		566
		567	Example: use two entirely different background images, depending on
		568	whether the window has focus.
		569
		570	FOCUS ? keep { load "has_focus.jpg" } : keep { load "no_focus.jpg" }
		571
		572	=cut
		573
		574	sub TX () { $frame->[FR_AGAIN]{position} = 1; $x }
		575	sub TY () { $frame->[FR_AGAIN]{position} = 1; $y }
		576	sub TW () { $frame->[FR_AGAIN]{size} = 1; $w }
		577	sub TH () { $frame->[FR_AGAIN]{size} = 1; $h }
		578	sub FOCUS() { $frame->[FR_AGAIN]{focus} = 1; $focus }
		579
		580	=item now
		581
		582	Returns the current time as (fractional) seconds since the epoch.
		583
		584	Using this expression does I<not> make your expression sensitive to time,
		585	but the next two functions do.
		586
		587	=item again $seconds
		588
		589	When this function is used the expression will be reevaluated again in
		590	C<$seconds> seconds.
		591
		592	Example: load some image and rotate it according to the time of day (as if it were
		593	the hour pointer of a clock). Update this image every minute.
		594
		595	again 60;
		596	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
		597
		598	=item counter $seconds
		599
		600	Like C<again>, but also returns an increasing counter value, starting at
		601	0, which might be useful for some simple animation effects.
		602
		603	=cut
		604
		605	sub now() { urxvt::NOW }
		606
		607	sub again($) {
		608	$frame->[FR_AGAIN]{time} = $_[0];
		609	}
		610
451	sub clone($) {	611	sub counter($) {
452	$_[0]->clone	612	$frame->[FR_AGAIN]{time} = $_[0];
		613	$frame->[FR_STATE]{counter} + 0
453	}	614	}
		615
		616	=back
		617
		618	=head2 SHAPE CHANGING OPERATORS
		619
		620	The following operators modify the shape, size or position of the image.
		621
		622	=over 4
454		623
455	=item clip $img	624	=item clip $img
456		625
457	=item clip $width, $height, $img	626	=item clip $width, $height, $img
458		627
…		…
461	Clips an image to the given rectangle. If the rectangle is outside the	630	Clips an image to the given rectangle. If the rectangle is outside the
462	image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is	631	image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is
463	larger than the image, then the tiling mode defines how the extra pixels	632	larger than the image, then the tiling mode defines how the extra pixels
464	will be filled.	633	will be filled.
465		634
466	If C<$x> an C<$y> are missing, then C<0> is assumed for both.	635	If C<$x> and C<$y> are missing, then C<0> is assumed for both.
467		636
468	If C<$width> and C<$height> are missing, then the window size will be	637	If C<$width> and C<$height> are missing, then the window size will be
469	assumed.	638	assumed.
470		639
471	Example: load an image, blur it, and clip it to the window size to save	640	Example: load an image, blur it, and clip it to the window size to save
472	memory.	641	memory.
473		642
474	clip blur 10, load "mybg.png"	643	clip keep { blur 10, load "mybg.png" }
475		644
476	=cut	645	=cut
477		646
478	sub clip($;$$;$$) {	647	sub clip($;$$;$$) {
479	my $img = pop;	648	my $img = pop;
…		…
489	=item scale $width_factor, $height_factor, $img	658	=item scale $width_factor, $height_factor, $img
490		659
491	Scales the image by the given factors in horizontal	660	Scales the image by the given factors in horizontal
492	(C<$width>) and vertical (C<$height>) direction.	661	(C<$width>) and vertical (C<$height>) direction.
493		662
494	If only one factor is give, it is used for both directions.	663	If only one factor is given, it is used for both directions.
495		664
496	If no factors are given, scales the image to the window size without	665	If no factors are given, scales the image to the window size without
497	keeping aspect.	666	keeping aspect.
498		667
499	=item resize $width, $height, $img	668	=item resize $width, $height, $img
…		…
552		721
553	Example: move the image right by 20 pixels and down by 30.	722	Example: move the image right by 20 pixels and down by 30.
554		723
555	move 20, 30, ...	724	move 20, 30, ...
556		725
		726	=item align $xalign, $yalign, $img
		727
		728	Aligns the image according to a factor - C<0> means the image is moved to
		729	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		730	exactly centered and C<1> means it touches the right or bottom edge.
		731
		732	Example: remove any visible border around an image, center it vertically but move
		733	it to the right hand side.
		734
		735	align 1, 0.5, pad $img
		736
557	=item center $img	737	=item center $img
558		738
559	=item center $width, $height, $img	739	=item center $width, $height, $img
560		740
561	Centers the image, i.e. the center of the image is moved to the center of	741	Centers the image, i.e. the center of the image is moved to the center of
562	the terminal window (or the box specified by C<$width> and C<$height> if	742	the terminal window (or the box specified by C<$width> and C<$height> if
563	given).	743	given).
		744
		745	Example: load an image and center it.
		746
		747	center keep { pad load "mybg.png" }
564		748
565	=item rootalign $img	749	=item rootalign $img
566		750
567	Moves the image so that it appears glued to the screen as opposed to the	751	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	752	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	753	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
570	top left of the screen.	754	top left of the screen.
571		755
572	Example: load a background image, put it in mirror mode and root align it.	756	Example: load a background image, put it in mirror mode and root align it.
573		757
574	rootalign mirror load "mybg.png"	758	rootalign keep { mirror load "mybg.png" }
575		759
576	Example: take the screen background and align it, giving the illusion of	760	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.	761	transparency as long as the window isn't in front of other windows.
578		762
579	rootalign root	763	rootalign root
580		764
581	=cut	765	=cut
582		766
583	sub move($$;$) {	767	sub move($$;$) {
584	my $img = pop->clone;	768	my $img = pop->clone;
585	$img->move ($_[0], $_[1]);	769	$img->move ($_[0], $_[1]);
586	$img	770	$img
587	}	771	}
588		772
		773	sub align($;$$) {
		774	my $img = pop;
		775
		776	move $_[0] * (TW - $img->w),
		777	$_[1] * (TH - $img->h),
		778	$img
		779	}
		780
589	sub center($;$$) {	781	sub center($;$$) {
590	my $img = pop;	782	my $img = pop;
591	my $w = $_[0] \|\| TW;	783	my $w = $_[0] \|\| TW;
592	my $h = $_[0] \|\| TH;	784	my $h = $_[1] \|\| TH;
593		785
594	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img	786	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
595	}	787	}
596		788
597	sub rootalign($) {	789	sub rootalign($) {
598	move -TX, -TY, $_[0]	790	move -TX, -TY, $_[0]
599	}	791	}
600		792
		793	=item rotate $center_x, $center_y, $degrees, $img
		794
		795	Rotates the image clockwise by C<$degrees> degrees, around the point at
		796	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		797
		798	Example: rotate the image by 90 degrees around its center.
		799
		800	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		801
		802	=cut
		803
		804	sub rotate($$$$) {
		805	my $img = pop;
		806	$img->rotate (
		807	$_[0] * ($img->w + $img->x),
		808	$_[1] * ($img->h + $img->y),
		809	$_[2] * (3.14159265 / 180),
		810	)
		811	}
		812
		813	=back
		814
		815	=head2 COLOUR MODIFICATIONS
		816
		817	The following operators change the pixels of the image.
		818
		819	=over 4
		820
		821	=item tint $color, $img
		822
		823	Tints the image in the given colour.
		824
		825	Example: tint the image red.
		826
		827	tint "red", load "rgb.png"
		828
		829	Example: the same, but specify the colour by component.
		830
		831	tint [1, 0, 0], load "rgb.png"
		832
		833	=cut
		834
		835	sub tint($$) {
		836	$_[1]->tint ($_[0])
		837	}
		838
		839	=item shade $factor, $img
		840
		841	Shade the image by the given factor.
		842
		843	=cut
		844
		845	sub shade($$) {
		846	$_[1]->shade ($_[0])
		847	}
		848
601	=item contrast $factor, $img	849	=item contrast $factor, $img
602		850
603	=item contrast $r, $g, $b, $img	851	=item contrast $r, $g, $b, $img
604		852
605	=item contrast $r, $g, $b, $a, $img	853	=item contrast $r, $g, $b, $a, $img
606		854
607	Adjusts the I<contrast> of an image.	855	Adjusts the I<contrast> of an image.
608		856
609	#TODO#	857	The first form applies a single C<$factor> to red, green and blue, the
		858	second form applies separate factors to each colour channel, and the last
		859	form includes the alpha channel.
610		860
		861	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		862	contrast.
		863
		864	Due to limitations in the underlying XRender extension, lowering contrast
		865	also reduces brightness, while increasing contrast currently also
		866	increases brightness.
		867
611	=item brightness $factor, $img	868	=item brightness $bias, $img
612		869
613	=item brightness $r, $g, $b, $img	870	=item brightness $r, $g, $b, $img
614		871
615	=item brightness $r, $g, $b, $a, $img	872	=item brightness $r, $g, $b, $a, $img
616		873
617	Adjusts the brightness of an image.	874	Adjusts the brightness of an image.
		875
		876	The first form applies a single C<$bias> to red, green and blue, the
		877	second form applies separate biases to each colour channel, and the last
		878	form includes the alpha channel.
		879
		880	Values less than 0 reduce brightness, while values larger than 0 increase
		881	it. Useful range is from -1 to 1 - the former results in a black, the
		882	latter in a white picture.
		883
		884	Due to idiosyncrasies in the underlying XRender extension, biases less
		885	than zero can be I<very> slow.
		886
		887	You can also try the experimental(!) C<muladd> operator.
618		888
619	=cut	889	=cut
620		890
621	sub contrast($$;$$;$) {	891	sub contrast($$;$$;$) {
622	my $img = pop;	892	my $img = pop;
623	my ($r, $g, $b, $a) = @_;	893	my ($r, $g, $b, $a) = @_;
624		894
625	($g, $b) = ($r, $r) if @_ < 4;	895	($g, $b) = ($r, $r) if @_ < 3;
626	$a = 1 if @_ < 5;	896	$a = 1 if @_ < 4;
627		897
628	$img = $img->clone;	898	$img = $img->clone;
629	$img->contrast ($r, $g, $b, $a);	899	$img->contrast ($r, $g, $b, $a);
630	$img	900	$img
631	}	901	}
632		902
633	sub brightness($$;$$;$) {	903	sub brightness($$;$$;$) {
634	my $img = pop;	904	my $img = pop;
635	my ($r, $g, $b, $a) = @_;	905	my ($r, $g, $b, $a) = @_;
636		906
637	($g, $b) = ($r, $r) if @_ < 4;	907	($g, $b) = ($r, $r) if @_ < 3;
638	$a = 1 if @_ < 5;	908	$a = 1 if @_ < 4;
639		909
640	$img = $img->clone;	910	$img = $img->clone;
641	$img->brightness ($r, $g, $b, $a);	911	$img->brightness ($r, $g, $b, $a);
642	$img	912	$img
		913	}
		914
		915	=item muladd $mul, $add, $img # EXPERIMENTAL
		916
		917	First multiplies the pixels by C<$mul>, then adds C<$add>. This can be used
		918	to implement brightness and contrast at the same time, with a wider value
		919	range than contrast and brightness operators.
		920
		921	Due to numerous bugs in XRender implementations, it can also introduce a
		922	number of visual artifacts.
		923
		924	Example: increase contrast by a factor of C<$c> without changing image
		925	brightness too much.
		926
		927	muladd $c, (1 - $c) * 0.5, $img
		928
		929	=cut
		930
		931	sub muladd($$$) {
		932	$_[2]->muladd ($_[0], $_[1])
643	}	933	}
644		934
645	=item blur $radius, $img	935	=item blur $radius, $img
646		936
647	=item blur $radius_horz, $radius_vert, $img	937	=item blur $radius_horz, $radius_vert, $img
…		…
659	sub blur($$;$) {	949	sub blur($$;$) {
660	my $img = pop;	950	my $img = pop;
661	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	951	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
662	}	952	}
663		953
664	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees	954	=item focus_fade $img
665		955
666	Rotates the image by C<$degrees> degrees, counter-clockwise, around the	956	=item focus_fade $factor, $img
667	pointer at C<$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		957
671	#TODO# new width, height, maybe more operators?	958	=item focus_fade $factor, $color, $img
672		959
673	Example: rotate the image by 90 degrees	960	Fades the image by the given factor (and colour) when focus is lost (the
		961	same as the C<-fade>/C<-fadecolor> command line options, which also supply
		962	the default values for C<factor> and C<$color>. Unlike with C<-fade>, the
		963	C<$factor> is a real value, not a percentage value (that is, 0..1, not
		964	0..100).
674		965
675	=cut	966	Example: do the right thing when focus fading is requested.
676		967
677	sub rotate($$$$$$) {	968	focus_fade load "mybg.jpg";
		969
		970	=cut
		971
		972	sub focus_fade($;$$) {
678	my $img = pop;	973	my $img = pop;
679	$img->rotate (	974
680	$_[0],	975	return $img
681	$_[1],	976	if FOCUS;
682	$_[2] * $img->w,	977
683	$_[3] * $img->h,	978	my $fade = @_ >= 1 ? $_[0] : defined $self->resource ("fade") ? $self->resource ("fade") * 0.01 : 0;
684	$_[4] * (3.14159265 / 180),	979	my $color = @_ >= 2 ? $_[1] : $self->resource ("color+" . urxvt::Color_fade);
685	)	980
		981	$img = $img->tint ($color) if $color ne "rgb:00/00/00";
		982	$img = $img->muladd (1 - $fade, 0) if $fade;
		983
		984	$img
686	}	985	}
687		986
688	=back	987	=back
689		988
		989	=head2 OTHER STUFF
		990
		991	Anything that didn't fit any of the other categories, even after applying
		992	force and closing our eyes.
		993
		994	=over 4
		995
		996	=item keep { ... }
		997
		998	This operator takes a code block as argument, that is, one or more
		999	statements enclosed by braces.
		1000
		1001	The trick is that this code block is only evaluated when the outcome
		1002	changes - on other calls the C<keep> simply returns the image it computed
		1003	previously (yes, it should only be used with images). Or in other words,
		1004	C<keep> I<caches> the result of the code block so it doesn't need to be
		1005	computed again.
		1006
		1007	This can be extremely useful to avoid redoing slow operations - for
		1008	example, if your background expression takes the root background, blurs it
		1009	and then root-aligns it it would have to blur the root background on every
		1010	window move or resize.
		1011
		1012	Another example is C<load>, which can be quite slow.
		1013
		1014	In fact, urxvt itself encloses the whole expression in some kind of
		1015	C<keep> block so it only is reevaluated as required.
		1016
		1017	Putting the blur into a C<keep> block will make sure the blur is only done
		1018	once, while the C<rootalign> is still done each time the window moves.
		1019
		1020	rootalign keep { blur 10, root }
		1021
		1022	This leaves the question of how to force reevaluation of the block,
		1023	in case the root background changes: If expression inside the block
		1024	is sensitive to some event (root background changes, window geometry
		1025	changes), then it will be reevaluated automatically as needed.
		1026
		1027	=cut
		1028
		1029	sub keep(&) {
		1030	my $id = $_[0]+0;
		1031
		1032	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		1033
		1034	unless ($frame->[FR_CACHE]) {
		1035	$frame->[FR_CACHE] = [ $_[0]() ];
		1036
		1037	my $self = $self;
		1038	my $frame = $frame;
		1039	Scalar::Util::weaken $frame;
		1040	$self->compile_frame ($frame, sub {
		1041	# clear this frame cache, also for all parents
		1042	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		1043	undef $frame->[FR_CACHE];
		1044	}
		1045
		1046	$self->recalculate;
		1047	});
		1048	};
		1049
		1050	# in scalar context we always return the first original result, which
		1051	# is not quite how perl works.
		1052	wantarray
		1053	? @{ $frame->[FR_CACHE] }
		1054	: $frame->[FR_CACHE][0]
		1055	}
		1056
		1057	# sub keep_clear() {
		1058	# delete $self->{frame_cache};
		1059	# }
		1060
		1061	=back
		1062
690	=cut	1063	=cut
691		1064
692	}	1065	}
693		1066
694	sub parse_expr {	1067	sub parse_expr {
695	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	1068	my $expr = eval
		1069	"sub {\n"
		1070	. "package urxvt::bgdsl;\n"
		1071	. "#line 0 'background expression'\n"
		1072	. "$_[0]\n"
		1073	. "}";
696	die if $@;	1074	die if $@;
697	$expr	1075	$expr
698	}	1076	}
699		1077
700	# compiles a parsed expression	1078	# compiles a parsed expression
701	sub set_expr {	1079	sub set_expr {
702	my ($self, $expr) = @_;	1080	my ($self, $expr) = @_;
703		1081
		1082	$self->{root} = []; # the outermost frame
704	$self->{expr} = $expr;	1083	$self->{expr} = $expr;
705	$self->recalculate;	1084	$self->recalculate;
		1085	}
		1086
		1087	# takes a hash of sensitivity indicators and installs watchers
		1088	sub compile_frame {
		1089	my ($self, $frame, $cb) = @_;
		1090
		1091	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		1092	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		1093
		1094	# don't keep stuff alive
		1095	Scalar::Util::weaken $state;
		1096
		1097	if ($again->{nested}) {
		1098	$state->{nested} = 1;
		1099	} else {
		1100	delete $state->{nested};
		1101	}
		1102
		1103	if (my $interval = $again->{time}) {
		1104	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		1105	if $state->{time}[0] != $interval;
		1106
		1107	# callback might have changed, although we could just rule that out
		1108	$state->{time}[1]->cb (sub {
		1109	++$state->{counter};
		1110	$cb->();
		1111	});
		1112	} else {
		1113	delete $state->{time};
		1114	}
		1115
		1116	if ($again->{position}) {
		1117	$state->{position} = $self->on (position_change => $cb);
		1118	} else {
		1119	delete $state->{position};
		1120	}
		1121
		1122	if ($again->{size}) {
		1123	$state->{size} = $self->on (size_change => $cb);
		1124	} else {
		1125	delete $state->{size};
		1126	}
		1127
		1128	if ($again->{rootpmap}) {
		1129	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		1130	} else {
		1131	delete $state->{rootpmap};
		1132	}
		1133
		1134	if ($again->{focus}) {
		1135	$state->{focus} = $self->on (focus_in => $cb, focus_out => $cb);
		1136	} else {
		1137	delete $state->{focus};
		1138	}
706	}	1139	}
707		1140
708	# evaluate the current bg expression	1141	# evaluate the current bg expression
709	sub recalculate {	1142	sub recalculate {
710	my ($arg_self) = @_;	1143	my ($arg_self) = @_;
…		…
720		1153
721	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1154	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
722		1155
723	# set environment to evaluate user expression	1156	# set environment to evaluate user expression
724		1157
725	local $self = $arg_self;	1158	local $self = $arg_self;
726
727	local $HOME = $ENV{HOME};	1159	local $HOME = $ENV{HOME};
728	local $old = $self->{state};	1160	local $frame = $self->{root};
729	local $new = my $state = $self->{state} = {};
730		1161
731	($x, $y, $w, $h) =
732	$self->background_geometry ($self->{border});	1162	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
		1163	$focus = $self->focus;
733		1164
734	# evaluate user expression	1165	# evaluate user expression
735		1166
736	my $img = eval { $self->{expr}->() };	1167	my @img = eval { $self->{expr}->() };
737	warn $@ if $@;#d#	1168	die $@ if $@;
		1169	die "background-expr did not return anything.\n" unless @img;
		1170	die "background-expr: expected image(s), got something else.\n"
738	die if !UNIVERSAL::isa $img, "urxvt::img";	1171	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
739		1172
740	$state->{size_sensitive} = 1	1173	my $img = urxvt::bgdsl::merge @img;
		1174
		1175	$frame->[FR_AGAIN]{size} = 1
741	if $img->repeat_mode != urxvt::RepeatNormal;	1176	if $img->repeat_mode != urxvt::RepeatNormal;
742		1177
743	# if the expression is sensitive to external events, prepare reevaluation then	1178	# if the expression is sensitive to external events, prepare reevaluation then
744		1179	$self->compile_frame ($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	$self->disable ("rootpmap_change");
777	}
778		1180
779	# clear stuff we no longer need	1181	# clear stuff we no longer need
780		1182
781	%$old = ();	1183	# unless (%{ $frame->[FR_STATE] }) {
782
783	unless ($repeat) {
784	delete $self->{state};	1184	# delete $self->{state};
785	delete $self->{expr};	1185	# delete $self->{expr};
786	}	1186	# }
787		1187
788	# set background pixmap	1188	# set background pixmap
789		1189
790	$self->set_background ($img, $self->{border});	1190	$self->set_background ($img, $self->{border});
791	$self->scr_recolour (0);	1191	$self->scr_recolour (0);
…		…
793	}	1193	}
794		1194
795	sub on_start {	1195	sub on_start {
796	my ($self) = @_;	1196	my ($self) = @_;
797		1197
798	my $expr = $self->x_resource ("background.expr")	1198	my $expr = $self->x_resource ("%.expr")
799	or return;	1199	or return;
800		1200
		1201	$self->has_render
		1202	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1203
801	$self->set_expr (parse_expr $expr);	1204	$self->set_expr (parse_expr $expr);
802	$self->{border} = $self->x_resource_boolean ("background.border");	1205	$self->{border} = $self->x_resource_boolean ("%.border");
		1206
		1207	$MIN_INTERVAL = $self->x_resource ("%.interval");
803		1208
804	()	1209	()
805	}	1210	}
806		1211

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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 1.88 by root, Sat May 17 13:38:23 2014 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 1.88 by root, Sat May 17 13:38:23 2014 UTC