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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.43 by root, Sun Jun 10 11:23:20 2012 UTC vs.
Revision 1.72 by root, Mon Jul 2 02:01:41 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.
224		290
		291	=item load_uc $path
		292
		293	Load uncached - same as load, but does not cache the image, which means it
		294	is I<always> loaded from the filesystem again, even if another copy of it
		295	is in memory at the time.
		296
225	=cut	297	=cut
		298
		299	sub load_uc($) {
		300	$self->new_img_from_file ($_[0])
		301	}
226		302
227	sub load($) {	303	sub load($) {
228	my ($path) = @_;	304	my ($path) = @_;
229		305
230	$new->{load}{$path} = $old->{load}{$path} \|\| $self->new_img_from_file ($path);	306	$_IMG_CACHE{$path} \|\| do {
		307	my $img = load_uc $path;
		308	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		309	$img
		310	}
231	}	311	}
232		312
233	=item root	313	=item root
234		314
235	Returns the root window pixmap, that is, hopefully, the background image	315	Returns the root window pixmap, that is, hopefully, the background image
236	of your screen. The image is set to extend mode.	316	of your screen.
237		317
238	This function makes your expression root sensitive, that means it will be	318	This function makes your expression root sensitive, that means it will be
239	reevaluated when the bg image changes.	319	reevaluated when the bg image changes.
240		320
241	=cut	321	=cut
242		322
243	sub root() {	323	sub root() {
244	$new->{rootpmap_sensitive} = 1;	324	$frame->[FR_AGAIN]{rootpmap} = 1;
245	die "root op not supported, exg, we need you";	325	$self->new_img_from_root
246	}	326	}
247		327
248	=item solid $colour	328	=item solid $colour
249		329
250	=item solid $width, $height, $colour	330	=item solid $width, $height, $colour
…		…
258	=cut	338	=cut
259		339
260	sub solid($;$$) {	340	sub solid($;$$) {
261	my $colour = pop;	341	my $colour = pop;
262		342
263	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	343	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
264	$img->fill ($colour);	344	$img->fill ($colour);
265	$img	345	$img
266	}	346	}
267		347
268	=back	348	=item clone $img
269		349
270	=head2 VARIABLES	350	Returns an exact copy of the image. This is useful if you want to have
		351	multiple copies of the same image to apply different effects to.
271		352
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	353	=cut
314		354
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} = $_[0];
348	}
349
350	sub counter($) {	355	sub clone($) {
351	$new->{again} = $_[0];	356	$_[0]->clone
352	$self->{counter} + 0
353	}	357	}
354		358
355	=back	359	=item merge $img ...
		360
		361	Takes any number of images and merges them together, creating a single
		362	image containing them all. The tiling mode of the first image is used as
		363	the tiling mode of the resulting image.
		364
		365	This function is called automatically when an expression returns multiple
		366	images.
		367
		368	=cut
		369
		370	sub merge(@) {
		371	return $_[0] unless $#_;
		372
		373	# rather annoyingly clumsy, but optimisation is for another time
		374
		375	my $x0 = +1e9;
		376	my $y0 = +1e9;
		377	my $x1 = -1e9;
		378	my $y1 = -1e9;
		379
		380	for (@_) {
		381	my ($x, $y, $w, $h) = $_->geometry;
		382
		383	$x0 = $x if $x0 > $x;
		384	$y0 = $y if $y0 > $y;
		385
		386	$x += $w;
		387	$y += $h;
		388
		389	$x1 = $x if $x1 < $x;
		390	$y1 = $y if $y1 < $y;
		391	}
		392
		393	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		394	$base->repeat_mode ($_[0]->repeat_mode);
		395	$base->fill ([0, 0, 0, 0]);
		396
		397	$base->draw ($_)
		398	for @_;
		399
		400	$base
		401	}
356		402
357	=head2 TILING MODES	403	=head2 TILING MODES
358		404
359	The following operators modify the tiling mode of an image, that is, the	405	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.	406	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	436	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	437	image over another image or the background colour while leaving all
392	background pixels outside the image unchanged.	438	background pixels outside the image unchanged.
393		439
394	Example: load an image and display it in the upper left corner. The rest	440	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	441	of the space is left "empty" (transparent or whatever your compositor does
396	in alpha mode, else background colour).	442	in alpha mode, else background colour).
397		443
398	pad load "mybg.png"	444	pad load "mybg.png"
399		445
400	=item extend $img	446	=item extend $img
401		447
402	Extends the image over the whole plane, using the closest pixel in the	448	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	449	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	450	filtering operations and want the pixels outside the image to have the
405	same values as the pixels near the edge.	451	same values as the pixels near the edge.
406		452
407	Example: just for curiosity, how does this pixel extension stuff work?	453	Example: just for curiosity, how does this pixel extension stuff work?
408		454
…		…
434	$img	480	$img
435	}	481	}
436		482
437	=back	483	=back
438		484
439	=head2 PIXEL OPERATORS	485	=head2 VARIABLE VALUES
440		486
441	The following operators modify the image pixels in various ways.	487	The following functions provide variable data such as the terminal window
		488	dimensions. They are not (Perl-) variables, they just return stuff that
		489	varies. Most of them make your expression sensitive to some events, for
		490	example using C<TW> (terminal width) means your expression is evaluated
		491	again when the terminal is resized.
442		492
443	=over 4	493	=over 4
444		494
445	=item clone $img	495	=item TX
446		496
447	Returns an exact copy of the image.	497	=item TY
448		498
449	=cut	499	Return the X and Y coordinates of the terminal window (the terminal
		500	window is the full window by default, and the character area only when in
		501	border-respect mode).
450		502
		503	Using these functions make your expression sensitive to window moves.
		504
		505	These functions are mainly useful to align images to the root window.
		506
		507	Example: load an image and align it so it looks as if anchored to the
		508	background (that's exactly what C<rootalign> does btw.):
		509
		510	move -TX, -TY, keep { load "mybg.png" }
		511
		512	=item TW
		513
		514	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		515	terminal window is the full window by default, and the character area only
		516	when in border-respect mode).
		517
		518	Using these functions make your expression sensitive to window resizes.
		519
		520	These functions are mainly useful to scale images, or to clip images to
		521	the window size to conserve memory.
		522
		523	Example: take the screen background, clip it to the window size, blur it a
		524	bit, align it to the window position and use it as background.
		525
		526	clip move -TX, -TY, keep { blur 5, root }
		527
		528	=cut
		529
		530	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
		531	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
		532	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
		533	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
		534
		535	=item now
		536
		537	Returns the current time as (fractional) seconds since the epoch.
		538
		539	Using this expression does I<not> make your expression sensitive to time,
		540	but the next two functions do.
		541
		542	=item again $seconds
		543
		544	When this function is used the expression will be reevaluated again in
		545	C<$seconds> seconds.
		546
		547	Example: load some image and rotate it according to the time of day (as if it were
		548	the hour pointer of a clock). Update this image every minute.
		549
		550	again 60;
		551	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
		552
		553	=item counter $seconds
		554
		555	Like C<again>, but also returns an increasing counter value, starting at
		556	0, which might be useful for some simple animation effects.
		557
		558	=cut
		559
		560	sub now() { urxvt::NOW }
		561
		562	sub again($) {
		563	$frame->[FR_AGAIN]{time} = $_[0];
		564	}
		565
451	sub clone($) {	566	sub counter($) {
452	$_[0]->clone	567	$frame->[FR_AGAIN]{time} = $_[0];
		568	$frame->[FR_STATE]{counter} + 0
453	}	569	}
		570
		571	=back
		572
		573	=head2 SHAPE CHANGING OPERATORS
		574
		575	The following operators modify the shape, size or position of the image.
		576
		577	=over 4
454		578
455	=item clip $img	579	=item clip $img
456		580
457	=item clip $width, $height, $img	581	=item clip $width, $height, $img
458		582
…		…
469	assumed.	593	assumed.
470		594
471	Example: load an image, blur it, and clip it to the window size to save	595	Example: load an image, blur it, and clip it to the window size to save
472	memory.	596	memory.
473		597
474	clip blur 10, load "mybg.png"	598	clip keep { blur 10, load "mybg.png" }
475		599
476	=cut	600	=cut
477		601
478	sub clip($;$$;$$) {	602	sub clip($;$$;$$) {
479	my $img = pop;	603	my $img = pop;
…		…
552		676
553	Example: move the image right by 20 pixels and down by 30.	677	Example: move the image right by 20 pixels and down by 30.
554		678
555	move 20, 30, ...	679	move 20, 30, ...
556		680
		681	=item align $xalign, $yalign, $img
		682
		683	Aligns the image according to a factor - C<0> means the image is moved to
		684	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		685	exactly centered and C<1> means it touches the right or bottom edge.
		686
		687	Example: remove any visible border around an image, center it vertically but move
		688	it to the right hand side.
		689
		690	align 1, 0.5, pad $img
		691
		692	=item center $img
		693
		694	=item center $width, $height, $img
		695
		696	Centers the image, i.e. the center of the image is moved to the center of
		697	the terminal window (or the box specified by C<$width> and C<$height> if
		698	given).
		699
		700	Example: load an image and center it.
		701
		702	center keep { pad load "mybg.png" }
		703
557	=item rootalign $img	704	=item rootalign $img
558		705
559	Moves the image so that it appears glued to the screen as opposed to the	706	Moves the image so that it appears glued to the screen as opposed to the
560	window. This gives the illusion of a larger area behind the window. It is	707	window. This gives the illusion of a larger area behind the window. It is
561	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	708	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
562	top left of the screen.	709	top left of the screen.
563		710
564	Example: load a background image, put it in mirror mode and root align it.	711	Example: load a background image, put it in mirror mode and root align it.
565		712
566	rootalign mirror load "mybg.png"	713	rootalign keep { mirror load "mybg.png" }
567		714
568	Example: take the screen background and align it, giving the illusion of	715	Example: take the screen background and align it, giving the illusion of
569	transparency as long as the window isn't in front of other windows.	716	transparency as long as the window isn't in front of other windows.
570		717
571	rootalign root	718	rootalign root
572		719
573	=cut	720	=cut
574		721
575	sub move($$;$) {	722	sub move($$;$) {
576	my $img = pop->clone;	723	my $img = pop->clone;
577	$img->move ($_[0], $_[1]);	724	$img->move ($_[0], $_[1]);
578	$img	725	$img
579	}	726	}
580		727
		728	sub align($;$$) {
		729	my $img = pop;
		730
		731	move $_[0] * (TW - $img->w),
		732	$_[1] * (TH - $img->h),
		733	$img
		734	}
		735
		736	sub center($;$$) {
		737	my $img = pop;
		738	my $w = $_[0] \|\| TW;
		739	my $h = $_[1] \|\| TH;
		740
		741	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		742	}
		743
581	sub rootalign($) {	744	sub rootalign($) {
582	move -TX, -TY, $_[0]	745	move -TX, -TY, $_[0]
583	}	746	}
584		747
		748	=item rotate $center_x, $center_y, $degrees, $img
		749
		750	Rotates the image clockwise by C<$degrees> degrees, around the point at
		751	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		752
		753	Example: rotate the image by 90 degrees around it's center.
		754
		755	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		756
		757	=cut
		758
		759	sub rotate($$$$) {
		760	my $img = pop;
		761	$img->rotate (
		762	$_[0] * ($img->w + $img->x),
		763	$_[1] * ($img->h + $img->y),
		764	$_[2] * (3.14159265 / 180),
		765	)
		766	}
		767
		768	=back
		769
		770	=head2 COLOUR MODIFICATIONS
		771
		772	The following operators change the pixels of the image.
		773
		774	=over 4
		775
		776	=item tint $color, $img
		777
		778	Tints the image in the given colour.
		779
		780	Example: tint the image red.
		781
		782	tint "red", load "rgb.png"
		783
		784	Example: the same, but specify the colour by component.
		785
		786	tint [1, 0, 0], load "rgb.png"
		787
		788	=cut
		789
		790	sub tint($$) {
		791	$_[1]->tint ($_[0])
		792	}
		793
585	=item contrast $factor, $img	794	=item contrast $factor, $img
586		795
587	=item contrast $r, $g, $b, $img	796	=item contrast $r, $g, $b, $img
588		797
589	=item contrast $r, $g, $b, $a, $img	798	=item contrast $r, $g, $b, $a, $img
590		799
591	Adjusts the I<contrast> of an image.	800	Adjusts the I<contrast> of an image.
592		801
593	#TODO#	802	The first form applies a single C<$factor> to red, green and blue, the
		803	second form applies separate factors to each colour channel, and the last
		804	form includes the alpha channel.
594		805
		806	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		807	contrast.
		808
		809	Due to limitations in the underlying XRender extension, lowering contrast
		810	also reduces brightness, while increasing contrast currently also
		811	increases brightness.
		812
595	=item brightness $factor, $img	813	=item brightness $bias, $img
596		814
597	=item brightness $r, $g, $b, $img	815	=item brightness $r, $g, $b, $img
598		816
599	=item brightness $r, $g, $b, $a, $img	817	=item brightness $r, $g, $b, $a, $img
600		818
601	Adjusts the brightness of an image.	819	Adjusts the brightness of an image.
		820
		821	The first form applies a single C<$bias> to red, green and blue, the
		822	second form applies separate biases to each colour channel, and the last
		823	form includes the alpha channel.
		824
		825	Values less than 0 reduce brightness, while values larger than 0 increase
		826	it. Useful range is from -1 to 1 - the former results in a black, the
		827	latter in a white picture.
		828
		829	Due to idiosyncrasies in the underlying XRender extension, biases less
		830	than zero can be I<very> slow.
602		831
603	=cut	832	=cut
604		833
605	sub contrast($$;$$;$) {	834	sub contrast($$;$$;$) {
606	my $img = pop;	835	my $img = pop;
607	my ($r, $g, $b, $a) = @_;	836	my ($r, $g, $b, $a) = @_;
608		837
609	($g, $b) = ($r, $r) if @_ < 4;	838	($g, $b) = ($r, $r) if @_ < 3;
610	$a = 1 if @_ < 5;	839	$a = 1 if @_ < 4;
611		840
612	$img = $img->clone;	841	$img = $img->clone;
613	$img->contrast ($r, $g, $b, $a);	842	$img->contrast ($r, $g, $b, $a);
614	$img	843	$img
615	}	844	}
616		845
617	sub brightness($$;$$;$) {	846	sub brightness($$;$$;$) {
618	my $img = pop;	847	my $img = pop;
619	my ($r, $g, $b, $a) = @_;	848	my ($r, $g, $b, $a) = @_;
620		849
621	($g, $b) = ($r, $r) if @_ < 4;	850	($g, $b) = ($r, $r) if @_ < 3;
622	$a = 1 if @_ < 5;	851	$a = 1 if @_ < 4;
623		852
624	$img = $img->clone;	853	$img = $img->clone;
625	$img->brightness ($r, $g, $b, $a);	854	$img->brightness ($r, $g, $b, $a);
626	$img	855	$img
627	}	856	}
…		…
643	sub blur($$;$) {	872	sub blur($$;$) {
644	my $img = pop;	873	my $img = pop;
645	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	874	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
646	}	875	}
647		876
648	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
649
650	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
651	pointer at C<$center_x> and C<$center_y> (specified as factor of image
652	width/height), generating a new image with width C<$new_width> and height
653	C<$new_height>.
654
655	#TODO# new width, height, maybe more operators?
656
657	Example: rotate the image by 90 degrees
658
659	=cut
660
661	sub rotate($$$$$$) {
662	my $img = pop;
663	$img->rotate (
664	$_[0],
665	$_[1],
666	$_[2] * $img->w,
667	$_[3] * $img->h,
668	$_[4] * (3.14159265 / 180),
669	)
670	}
671
672	=back	877	=back
673		878
		879	=head2 OTHER STUFF
		880
		881	Anything that didn't fit any of the other categories, even after applying
		882	force and closing our eyes.
		883
		884	=over 4
		885
		886	=item keep { ... }
		887
		888	This operator takes a code block as argument, that is, one or more
		889	statements enclosed by braces.
		890
		891	The trick is that this code block is only evaluated when the outcome
		892	changes - on other calls the C<keep> simply returns the image it computed
		893	previously (yes, it should only be used with images). Or in other words,
		894	C<keep> I<caches> the result of the code block so it doesn't need to be
		895	computed again.
		896
		897	This can be extremely useful to avoid redoing slow operations - for
		898	example, if your background expression takes the root background, blurs it
		899	and then root-aligns it it would have to blur the root background on every
		900	window move or resize.
		901
		902	Another example is C<load>, which can be quite slow.
		903
		904	In fact, urxvt itself encloses the whole expression in some kind of
		905	C<keep> block so it only is reevaluated as required.
		906
		907	Putting the blur into a C<keep> block will make sure the blur is only done
		908	once, while the C<rootalign> is still done each time the window moves.
		909
		910	rootlign keep { blur 10, root }
		911
		912	This leaves the question of how to force reevaluation of the block,
		913	in case the root background changes: If expression inside the block
		914	is sensitive to some event (root background changes, window geometry
		915	changes), then it will be reevaluated automatically as needed.
		916
		917	=cut
		918
		919	sub keep(&) {
		920	my $id = $_[0]+0;
		921
		922	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		923
		924	unless ($frame->[FR_CACHE]) {
		925	$frame->[FR_CACHE] = [ $_[0]() ];
		926
		927	my $self = $self;
		928	my $frame = $frame;
		929	Scalar::Util::weaken $frame;
		930	$self->compile_frame ($frame, sub {
		931	# clear this frame cache, also for all parents
		932	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		933	undef $frame->[FR_CACHE];
		934	}
		935
		936	$self->recalculate;
		937	});
		938	};
		939
		940	# in scalar context we always return the first original result, which
		941	# is not quite how perl works.
		942	wantarray
		943	? @{ $frame->[FR_CACHE] }
		944	: $frame->[FR_CACHE][0]
		945	}
		946
		947	# sub keep_clear() {
		948	# delete $self->{frame_cache};
		949	# }
		950
		951	=back
		952
674	=cut	953	=cut
675		954
676	}	955	}
677		956
678	sub parse_expr {	957	sub parse_expr {
679	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	958	my $expr = eval
		959	"sub {\n"
		960	. "package urxvt::bgdsl;\n"
		961	. "#line 0 'background expression'\n"
		962	. "$_[0]\n"
		963	. "}";
680	die if $@;	964	die if $@;
681	$expr	965	$expr
682	}	966	}
683		967
684	# compiles a parsed expression	968	# compiles a parsed expression
685	sub set_expr {	969	sub set_expr {
686	my ($self, $expr) = @_;	970	my ($self, $expr) = @_;
687		971
		972	$self->{root} = [];
688	$self->{expr} = $expr;	973	$self->{expr} = $expr;
689	$self->recalculate;	974	$self->recalculate;
		975	}
		976
		977	# takes a hash of sensitivity indicators and installs watchers
		978	sub compile_frame {
		979	my ($self, $frame, $cb) = @_;
		980
		981	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		982	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		983
		984	# don't keep stuff alive
		985	Scalar::Util::weaken $state;
		986
		987	if ($again->{nested}) {
		988	$state->{nested} = 1;
		989	} else {
		990	delete $state->{nested};
		991	}
		992
		993	if (my $interval = $again->{time}) {
		994	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		995	if $state->{time}[0] != $interval;
		996
		997	# callback might have changed, although we could just rule that out
		998	$state->{time}[1]->cb (sub {
		999	++$state->{counter};
		1000	$cb->();
		1001	});
		1002	} else {
		1003	delete $state->{time};
		1004	}
		1005
		1006	if ($again->{position}) {
		1007	$state->{position} = $self->on (position_change => $cb);
		1008	} else {
		1009	delete $state->{position};
		1010	}
		1011
		1012	if ($again->{size}) {
		1013	$state->{size} = $self->on (size_change => $cb);
		1014	} else {
		1015	delete $state->{size};
		1016	}
		1017
		1018	if ($again->{rootpmap}) {
		1019	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		1020	} else {
		1021	delete $state->{rootpmap};
		1022	}
690	}	1023	}
691		1024
692	# evaluate the current bg expression	1025	# evaluate the current bg expression
693	sub recalculate {	1026	sub recalculate {
694	my ($arg_self) = @_;	1027	my ($arg_self) = @_;
…		…
704		1037
705	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1038	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
706		1039
707	# set environment to evaluate user expression	1040	# set environment to evaluate user expression
708		1041
709	local $self = $arg_self;	1042	local $self = $arg_self;
710
711	local $HOME = $ENV{HOME};	1043	local $HOME = $ENV{HOME};
712	local $old = $self->{state};	1044	local $frame = [];
713	local $new = my $state = $self->{state} = {};
714		1045
715	($x, $y, $w, $h) =
716	$self->background_geometry ($self->{border});	1046	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
717		1047
718	# evaluate user expression	1048	# evaluate user expression
719		1049
720	my $img = eval { $self->{expr}->() };	1050	my @img = eval { $self->{expr}->() };
721	warn $@ if $@;#d#	1051	die $@ if $@;
		1052	die "background-expr did not return anything.\n" unless @img;
		1053	die "background-expr: expected image(s), got something else.\n"
722	die if !UNIVERSAL::isa $img, "urxvt::img";	1054	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
723		1055
724	$state->{size_sensitive} = 1	1056	my $img = urxvt::bgdsl::merge @img;
		1057
		1058	$frame->[FR_AGAIN]{size} = 1
725	if $img->repeat_mode != urxvt::RepeatNormal;	1059	if $img->repeat_mode != urxvt::RepeatNormal;
726		1060
727	# if the expression is sensitive to external events, prepare reevaluation then	1061	# if the expression is sensitive to external events, prepare reevaluation then
728		1062	$self->compile_frame ($frame, sub { $arg_self->recalculate });
729	my $repeat;
730
731	if (my $again = $state->{again}) {
732	$repeat = 1;
733	my $self = $self;
734	$state->{timer} = $again == $old->{again}
735	? $old->{timer}
736	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
737	++$self->{counter};
738	$self->recalculate
739	});
740	}
741
742	if (delete $state->{position_sensitive}) {
743	$repeat = 1;
744	$self->enable (position_change => sub { $_[0]->recalculate });
745	} else {
746	$self->disable ("position_change");
747	}
748
749	if (delete $state->{size_sensitive}) {
750	$repeat = 1;
751	$self->enable (size_change => sub { $_[0]->recalculate });
752	} else {
753	$self->disable ("size_change");
754	}
755
756	if (delete $state->{rootpmap_sensitive}) {
757	$repeat = 1;
758	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
759	} else {
760	$self->disable ("rootpmap_change");
761	}
762		1063
763	# clear stuff we no longer need	1064	# clear stuff we no longer need
764		1065
765	%$old = ();	1066	# unless (%{ $frame->[FR_STATE] }) {
766
767	unless ($repeat) {
768	delete $self->{state};	1067	# delete $self->{state};
769	delete $self->{expr};	1068	# delete $self->{expr};
770	}	1069	# }
771		1070
772	# set background pixmap	1071	# set background pixmap
773		1072
774	$self->set_background ($img, $self->{border});	1073	$self->set_background ($img, $self->{border});
775	$self->scr_recolour (0);	1074	$self->scr_recolour (0);
…		…
777	}	1076	}
778		1077
779	sub on_start {	1078	sub on_start {
780	my ($self) = @_;	1079	my ($self) = @_;
781		1080
782	my $expr = $self->x_resource ("background.expr")	1081	my $expr = $self->x_resource ("%.expr")
783	or return;	1082	or return;
784		1083
		1084	$self->has_render
		1085	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1086
785	$self->set_expr (parse_expr $expr);	1087	$self->set_expr (parse_expr $expr);
786	$self->{border} = $self->x_resource_boolean ("background.border");	1088	$self->{border} = $self->x_resource_boolean ("%.border");
		1089
		1090	$MIN_INTERVAL = $self->x_resource ("%.interval");
787		1091
788	()	1092	()
789	}	1093	}
790		1094

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.43 by root, Sun Jun 10 11:23:20 2012 UTC vs. Revision 1.72 by root, Mon Jul 2 02:01:41 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.43 by root, Sun Jun 10 11:23:20 2012 UTC vs.
Revision 1.72 by root, Mon Jul 2 02:01:41 2012 UTC