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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.48 by root, Sun Jun 10 15:01:14 2012 UTC vs.
Revision 1.74 by root, Sat Jul 14 08:42:54 2012 UTC

…		…
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	#:META:X_RESOURCE:%.interval:seconds:minimum time between updates	5	#:META:X_RESOURCE:%.interval:seconds:minimum time between updates
6		6
7	#TODO: once, rootalign
8
9	=head1 NAME	7	=head1 NAME
10		8
11	background - manage terminal background	9	background - manage terminal background
12		10
13	=head1 SYNOPSIS	11	=head1 SYNOPSIS
…		…
28	to be as simple as possible.	26	to be as simple as possible.
29		27
30	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
31	use:	29	use:
32		30
33	urxvt --background-expr 'scale load "/path/to/mybg.png"'	31	urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
34		32
35	Or specified as a X resource:	33	Or specified as a X resource:
36		34
37	URxvt.background-expr: scale load "/path/to/mybg.png"	35	URxvt.background-expr: scale keep { load "/path/to/mybg.png" }
38		36
39	=head1 THEORY OF OPERATION	37	=head1 THEORY OF OPERATION
40		38
41	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
42	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
…		…
55	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
56	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
57	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
58	timer elapses), then the expression will be evaluated again.	56	timer elapses), then the expression will be evaluated again.
59		57
60	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"
61	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
62	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
63	example. That ensures that the picture always fills the terminal, even	61	example. That ensures that the picture always fills the terminal, even
64	after it's size changes.	62	after its size changes.
65		63
66	=head2 EXPRESSIONS	64	=head2 EXPRESSIONS
67		65
68	Expressions are normal Perl expressions, in fact, they are Perl blocks -	66	Expressions are normal Perl expressions, in fact, they are Perl blocks -
69	which means you could use multiple lines and statements:	67	which means you could use multiple lines and statements:
70		68
		69	scale keep {
71	again 3600;	70	again 3600;
72	if (localtime now)[6]) {	71	if (localtime now)[6]) {
73	return scale load "$HOME/weekday.png";	72	return load "$HOME/weekday.png";
74	} else {	73	} else {
75	return scale load "$HOME/sunday.png";	74	return load "$HOME/sunday.png";
		75	}
76	}	76	}
77		77
78	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	terminal window is resized). It sets F<sunday.png> as background on
79	background on Sundays, and F<weekday.png> on all other days.	80	Sundays, and F<weekday.png> on all other days.
80		81
81	Fortunately, we expect that most expressions will be much simpler, with	82	Fortunately, we expect that most expressions will be much simpler, with
82	little Perl knowledge needed.	83	little Perl knowledge needed.
83		84
84	Basically, you always start with a function that "generates" an image	85	Basically, you always start with a function that "generates" an image
…		…
117	horizontal and vertical dimensions. For example, this halves the image	118	horizontal and vertical dimensions. For example, this halves the image
118	width and doubles the image height:	119	width and doubles the image height:
119		120
120	scale 0.5, 2, load "$HOME/mypic.png"	121	scale 0.5, 2, load "$HOME/mypic.png"
121		122
122	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,
123	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 again
		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:
124		127
		128	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		129
		130	The C<keep> operator executes all the statements inside the braces only
		131	once, or when it thinks the outcome might change. In other cases it
		132	returns the last value computed by the brace block.
		133
		134	This means that the C<load> is only executed once, which makes it much
		135	faster, but also means that more memory is being used, because the loaded
		136	image must be kept in memory at all times. In this expression, the
		137	trade-off is likely worth it.
		138
		139	But back to effects: Other effects than scaling are also readily
		140	available, for example, you can tile the image to fill the whole window,
		141	instead of resizing it:
		142
125	tile load "$HOME/mypic.png"	143	tile keep { load "$HOME/mypic.png" }
126		144
127	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator	145	In fact, images returned by C<load> are in C<tile> mode by default, so the
128	is kind of superfluous.	146	C<tile> operator is kind of superfluous.
129		147
130	Another common effect is to mirror the image, so that the same edges touch:	148	Another common effect is to mirror the image, so that the same edges
		149	touch:
131		150
132	mirror load "$HOME/mypic.png"	151	mirror keep { load "$HOME/mypic.png" }
133		152
134	This is also a typical background expression:	153	Another common background expression is:
135		154
136	rootalign root	155	rootalign root
137		156
138	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
139	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
140	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:
141	moved around.	160	the image seems to be static while the window is moved around.
142		161
143	=head2 CYCLES AND CACHING	162	=head2 COLOUR SPECIFICATIONS
144		163
145	As has been mentioned before, the expression might be evaluated multiple	164	Whenever an operator expects a "colour", then this can be specified in one
146	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:
147	have begun. Many operators cache their results till the next cycle.
148		166
149	For example, the C<load> operator keeps a copy of the image. If it is	167	"red" # named colour
150	asked to load the same image on the next cycle it will not load it again,	168	"#f00" # simple rgb
151	but return the cached copy.	169	"[50]red" # red with 50% alpha
		170	"TekHVC:300/50/50" # anything goes
152		171
153	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:
154	image every time, it will always be cached, but when you load a different
155	image, it will forget about the first one.
156		173
157	This allows you to either speed things up by keeping multiple images in	174	[0.5] # 50% gray, 100% alpha
158	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
159		177
160	For example, you can keep two images in memory and use a random one like	178	=head2 CACHING AND SENSITIVITY
161	this:
162		179
163	my $img1 = load "img1.png";	180	Since some operations (such as C<load> and C<blur>) can take a long time,
164	my $img2 = load "img2.png";	181	caching results can be very important for a smooth operation. Caching can
165	(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.
166		185
167	Since both images are "loaded" every time the expression is evaluated,	186	=head3 C<keep { ... }> caching
168	they are always kept in memory. Contrast this version:
169		187
170	my $path1 = "img1.png";	188	The most important way to cache expensive operations is to use C<keep {
171	my $path2 = "img2.png";	189	... }>. The C<keep> operator takes a block of multiple statements enclosed
172	load ((0.5 > rand) ? $path1 : $path2)	190	by C<{}> and keeps the return value in memory.
173		191
174	Here, a path is selected randomly, and load is only called for one image,	192	An expression can be "sensitive" to various external events, such as
175	so keeps only one image in memory. If, on the next evaluation, luck	193	scaling or moving the window, root background changes and timers. Simply
176	decides to use the other path, then it will have to load that image again.	194	using an expression (such as C<scale> without parameters) that depends on
		195	certain changing values (called "variables"), or using those variables
		196	directly, will make an expression sensitive to these events - for example,
		197	using C<scale> or C<TW> will make the expression sensitive to the terminal
		198	size, and thus to resizing events.
		199
		200	When such an event happens, C<keep> will automatically trigger a
		201	reevaluation of the whole expression with the new value of the expression.
		202
		203	C<keep> is most useful for expensive operations, such as C<blur>:
		204
		205	rootalign keep { blur 20, root }
		206
		207	This makes a blurred copy of the root background once, and on subsequent
		208	calls, just root-aligns it. Since C<blur> is usually quite slow and
		209	C<rootalign> is quite fast, this trades extra memory (for the cached
		210	blurred pixmap) with speed (blur only needs to be redone when root
		211	changes).
		212
		213	=head3 C<load> caching
		214
		215	The C<load> operator itself does not keep images in memory, but as long as
		216	the image is still in memory, C<load> will use the in-memory image instead
		217	of loading it freshly from disk.
		218
		219	That means that this expression:
		220
		221	keep { load "$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.
177		225
178	=head1 REFERENCE	226	=head1 REFERENCE
179		227
180	=head2 COMMAND LINE SWITCHES	228	=head2 COMMAND LINE SWITCHES
181		229
…		…
193	Specifying this flag changes the behaviour, so that the image only	241	Specifying this flag changes the behaviour, so that the image only
194	replaces the background of the character area.	242	replaces the background of the character area.
195		243
196	=item --background-interval seconds	244	=item --background-interval seconds
197		245
198	Since some operations in the underlying XRender extension can effetively	246	Since some operations in the underlying XRender extension can effectively
199	freeze your X-server for prolonged time, this extension enforces a minimum	247	freeze your X-server for prolonged time, this extension enforces a minimum
200	time between updates, which is normally about 0.1 seconds.	248	time between updates, which is normally about 0.1 seconds.
201		249
202	If you want to do updates more often, you can decrease this safety	250	If you want to do updates more often, you can decrease this safety
203	interval with this switch.	251	interval with this switch.
204		252
205	=back	253	=back
206		254
207	=cut	255	=cut
208		256
		257	our %_IMG_CACHE;
209	our $HOME;	258	our $HOME;
210	our ($self, $old, $new);	259	our ($self, $frame);
211	our ($x, $y, $w, $h);	260	our ($x, $y, $w, $h);
212		261
213	# enforce at least this interval between updates	262	# enforce at least this interval between updates
214	our $MIN_INTERVAL = 6/59.951;	263	our $MIN_INTERVAL = 6/59.951;
215		264
216	{	265	{
217	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.
218		272
219	use List::Util qw(min max sum shuffle);	273	use List::Util qw(min max sum shuffle);
220		274
221	=head2 PROVIDERS/GENERATORS	275	=head2 PROVIDERS/GENERATORS
222		276
…		…
229	=item load $path	283	=item load $path
230		284
231	Loads the image at the given C<$path>. The image is set to plane tiling	285	Loads the image at the given C<$path>. The image is set to plane tiling
232	mode.	286	mode.
233		287
234	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.
235		290
		291	=item load_uc $path
		292
		293	Load uncached - same as load, but does not cache the image, which means it
		294	is I<always> loaded from the filesystem again, even if another copy of it
		295	is in memory at the time.
		296
236	=cut	297	=cut
		298
		299	sub load_uc($) {
		300	$self->new_img_from_file ($_[0])
		301	}
237		302
238	sub load($) {	303	sub load($) {
239	my ($path) = @_;	304	my ($path) = @_;
240		305
241	$new->{load}{$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	}
242	}	311	}
243		312
244	=item root	313	=item root
245		314
246	Returns the root window pixmap, that is, hopefully, the background image	315	Returns the root window pixmap, that is, hopefully, the background image
247	of your screen. The image is set to extend mode.	316	of your screen.
248		317
249	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
250	reevaluated when the bg image changes.	319	reevaluated when the bg image changes.
251		320
252	=cut	321	=cut
253		322
254	sub root() {	323	sub root() {
255	$new->{rootpmap_sensitive} = 1;	324	$frame->[FR_AGAIN]{rootpmap} = 1;
256	die "root op not supported, exg, we need you";	325	$self->new_img_from_root
257	}	326	}
258		327
259	=item solid $colour	328	=item solid $colour
260		329
261	=item solid $width, $height, $colour	330	=item solid $width, $height, $colour
…		…
269	=cut	338	=cut
270		339
271	sub solid($;$$) {	340	sub solid($;$$) {
272	my $colour = pop;	341	my $colour = pop;
273		342
274	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);
275	$img->fill ($colour);	344	$img->fill ($colour);
276	$img	345	$img
277	}	346	}
278		347
279	=item clone $img	348	=item clone $img
…		…
285		354
286	sub clone($) {	355	sub clone($) {
287	$_[0]->clone	356	$_[0]->clone
288	}	357	}
289		358
290	=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	}
291		402
292	=head2 TILING MODES	403	=head2 TILING MODES
293		404
294	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
295	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.
…		…
325	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
326	image over another image or the background colour while leaving all	437	image over another image or the background colour while leaving all
327	background pixels outside the image unchanged.	438	background pixels outside the image unchanged.
328		439
329	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
330	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
331	in alpha mode, else background colour).	442	in alpha mode, else background colour).
332		443
333	pad load "mybg.png"	444	pad load "mybg.png"
334		445
335	=item extend $img	446	=item extend $img
336		447
337	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
338	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
339	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
340	same values as the pixels near the edge.	451	same values as the pixels near the edge.
341		452
342	Example: just for curiosity, how does this pixel extension stuff work?	453	Example: just for curiosity, how does this pixel extension stuff work?
343		454
…		…
392	Using these functions make your expression sensitive to window moves.	503	Using these functions make your expression sensitive to window moves.
393		504
394	These functions are mainly useful to align images to the root window.	505	These functions are mainly useful to align images to the root window.
395		506
396	Example: load an image and align it so it looks as if anchored to the	507	Example: load an image and align it so it looks as if anchored to the
397	background.	508	background (that's exactly what C<rootalign> does btw.):
398		509
399	move -TX, -TY, load "mybg.png"	510	move -TX, -TY, keep { load "mybg.png" }
400		511
401	=item TW	512	=item TW
402		513
403	Return the width (C<TW>) and height (C<TH>) of the terminal window (the	514	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
404	terminal window is the full window by default, and the character area only	515	terminal window is the full window by default, and the character area only
…		…
410	the window size to conserve memory.	521	the window size to conserve memory.
411		522
412	Example: take the screen background, clip it to the window size, blur it a	523	Example: take the screen background, clip it to the window size, blur it a
413	bit, align it to the window position and use it as background.	524	bit, align it to the window position and use it as background.
414		525
415	clip move -TX, -TY, blur 5, root	526	clip move -TX, -TY, keep { blur 5, root }
416		527
417	=cut	528	=cut
418		529
419	sub TX() { $new->{position_sensitive} = 1; $x }	530	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
420	sub TY() { $new->{position_sensitive} = 1; $y }	531	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
421	sub TW() { $new->{size_sensitive} = 1; $w }	532	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
422	sub TH() { $new->{size_sensitive} = 1; $h }	533	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
423		534
424	=item now	535	=item now
425		536
426	Returns the current time as (fractional) seconds since the epoch.	537	Returns the current time as (fractional) seconds since the epoch.
427		538
…		…
434	C<$seconds> seconds.	545	C<$seconds> seconds.
435		546
436	Example: load some image and rotate it according to the time of day (as if it were	547	Example: load some image and rotate it according to the time of day (as if it were
437	the hour pointer of a clock). Update this image every minute.	548	the hour pointer of a clock). Update this image every minute.
438		549
		550	again 60;
439	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"	551	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
440		552
441	=item counter $seconds	553	=item counter $seconds
442		554
443	Like C<again>, but also returns an increasing counter value, starting at	555	Like C<again>, but also returns an increasing counter value, starting at
444	0, which might be useful for some simple animation effects.	556	0, which might be useful for some simple animation effects.
…		…
446	=cut	558	=cut
447		559
448	sub now() { urxvt::NOW }	560	sub now() { urxvt::NOW }
449		561
450	sub again($) {	562	sub again($) {
451	$new->{again} = $_[0];	563	$frame->[FR_AGAIN]{time} = $_[0];
452	}	564	}
453		565
454	sub counter($) {	566	sub counter($) {
455	$new->{again} = $_[0];	567	$frame->[FR_AGAIN]{time} = $_[0];
456	$self->{counter} + 0	568	$frame->[FR_STATE]{counter} + 0
457	}	569	}
458		570
459	=back	571	=back
460		572
461	=head2 SHAPE CHANGING OPERATORS	573	=head2 SHAPE CHANGING OPERATORS
…		…
481	assumed.	593	assumed.
482		594
483	Example: load an image, blur it, and clip it to the window size to save	595	Example: load an image, blur it, and clip it to the window size to save
484	memory.	596	memory.
485		597
486	clip blur 10, load "mybg.png"	598	clip keep { blur 10, load "mybg.png" }
487		599
488	=cut	600	=cut
489		601
490	sub clip($;$$;$$) {	602	sub clip($;$$;$$) {
491	my $img = pop;	603	my $img = pop;
…		…
585	the terminal window (or the box specified by C<$width> and C<$height> if	697	the terminal window (or the box specified by C<$width> and C<$height> if
586	given).	698	given).
587		699
588	Example: load an image and center it.	700	Example: load an image and center it.
589		701
590	center pad load "mybg.png"	702	center keep { pad load "mybg.png" }
591		703
592	=item rootalign $img	704	=item rootalign $img
593		705
594	Moves the image so that it appears glued to the screen as opposed to the	706	Moves the image so that it appears glued to the screen as opposed to the
595	window. This gives the illusion of a larger area behind the window. It is	707	window. This gives the illusion of a larger area behind the window. It is
596	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	708	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
597	top left of the screen.	709	top left of the screen.
598		710
599	Example: load a background image, put it in mirror mode and root align it.	711	Example: load a background image, put it in mirror mode and root align it.
600		712
601	rootalign mirror load "mybg.png"	713	rootalign keep { mirror load "mybg.png" }
602		714
603	Example: take the screen background and align it, giving the illusion of	715	Example: take the screen background and align it, giving the illusion of
604	transparency as long as the window isn't in front of other windows.	716	transparency as long as the window isn't in front of other windows.
605		717
606	rootalign root	718	rootalign root
…		…
631		743
632	sub rootalign($) {	744	sub rootalign($) {
633	move -TX, -TY, $_[0]	745	move -TX, -TY, $_[0]
634	}	746	}
635		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($$$$) {
		760	my $img = pop;
		761	$img->rotate (
		762	$_[0] * ($img->w + $img->x),
		763	$_[1] * ($img->h + $img->y),
		764	$_[2] * (3.14159265 / 180),
		765	)
		766	}
		767
636	=back	768	=back
637		769
638	=head2 COLOUR MODIFICATIONS	770	=head2 COLOUR MODIFICATIONS
639		771
640	The following operators change the pixels of the image.	772	The following operators change the pixels of the image.
641		773
642	=over 4	774	=over 4
		775
		776	=item tint $color, $img
		777
		778	Tints the image in the given colour.
		779
		780	Example: tint the image red.
		781
		782	tint "red", load "rgb.png"
		783
		784	Example: the same, but specify the colour by component.
		785
		786	tint [1, 0, 0], load "rgb.png"
		787
		788	=cut
		789
		790	sub tint($$) {
		791	$_[1]->tint ($_[0])
		792	}
643		793
644	=item contrast $factor, $img	794	=item contrast $factor, $img
645		795
646	=item contrast $r, $g, $b, $img	796	=item contrast $r, $g, $b, $img
647		797
…		…
674		824
675	Values less than 0 reduce brightness, while values larger than 0 increase	825	Values less than 0 reduce brightness, while values larger than 0 increase
676	it. Useful range is from -1 to 1 - the former results in a black, the	826	it. Useful range is from -1 to 1 - the former results in a black, the
677	latter in a white picture.	827	latter in a white picture.
678		828
679	Due to idiosynchrasies in the underlying XRender extension, biases less	829	Due to idiosyncrasies in the underlying XRender extension, biases less
680	than zero can be I<very> slow.	830	than zero can be I<very> slow.
681		831
682	=cut	832	=cut
683		833
684	sub contrast($$;$$;$) {	834	sub contrast($$;$$;$) {
685	my $img = pop;	835	my $img = pop;
686	my ($r, $g, $b, $a) = @_;	836	my ($r, $g, $b, $a) = @_;
687		837
688	($g, $b) = ($r, $r) if @_ < 4;	838	($g, $b) = ($r, $r) if @_ < 3;
689	$a = 1 if @_ < 5;	839	$a = 1 if @_ < 4;
690		840
691	$img = $img->clone;	841	$img = $img->clone;
692	$img->contrast ($r, $g, $b, $a);	842	$img->contrast ($r, $g, $b, $a);
693	$img	843	$img
694	}	844	}
695		845
696	sub brightness($$;$$;$) {	846	sub brightness($$;$$;$) {
697	my $img = pop;	847	my $img = pop;
698	my ($r, $g, $b, $a) = @_;	848	my ($r, $g, $b, $a) = @_;
699		849
700	($g, $b) = ($r, $r) if @_ < 4;	850	($g, $b) = ($r, $r) if @_ < 3;
701	$a = 1 if @_ < 5;	851	$a = 1 if @_ < 4;
702		852
703	$img = $img->clone;	853	$img = $img->clone;
704	$img->brightness ($r, $g, $b, $a);	854	$img->brightness ($r, $g, $b, $a);
705	$img	855	$img
706	}	856	}
…		…
722	sub blur($$;$) {	872	sub blur($$;$) {
723	my $img = pop;	873	my $img = pop;
724	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	874	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
725	}	875	}
726		876
727	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
728
729	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
730	pointer at C<$center_x> and C<$center_y> (specified as factor of image
731	width/height), generating a new image with width C<$new_width> and height
732	C<$new_height>.
733
734	#TODO# new width, height, maybe more operators?
735
736	Example: rotate the image by 90 degrees
737
738	=cut
739
740	sub rotate($$$$$$) {
741	my $img = pop;
742	$img->rotate (
743	$_[0],
744	$_[1],
745	$_[2] * $img->w,
746	$_[3] * $img->h,
747	$_[4] * (3.14159265 / 180),
748	)
749	}
750
751	=back	877	=back
752		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	rootalign 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
753	=cut	953	=cut
754		954
755	}	955	}
756		956
757	sub parse_expr {	957	sub parse_expr {
758	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	. "}";
759	die if $@;	964	die if $@;
760	$expr	965	$expr
761	}	966	}
762		967
763	# compiles a parsed expression	968	# compiles a parsed expression
764	sub set_expr {	969	sub set_expr {
765	my ($self, $expr) = @_;	970	my ($self, $expr) = @_;
766		971
		972	$self->{root} = []; # the outermost frame
767	$self->{expr} = $expr;	973	$self->{expr} = $expr;
768	$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 $state->{rootpmap};
		1022	}
769	}	1023	}
770		1024
771	# evaluate the current bg expression	1025	# evaluate the current bg expression
772	sub recalculate {	1026	sub recalculate {
773	my ($arg_self) = @_;	1027	my ($arg_self) = @_;
…		…
783		1037
784	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1038	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
785		1039
786	# set environment to evaluate user expression	1040	# set environment to evaluate user expression
787		1041
788	local $self = $arg_self;	1042	local $self = $arg_self;
789
790	local $HOME = $ENV{HOME};	1043	local $HOME = $ENV{HOME};
791	local $old = $self->{state};	1044	local $frame = $self->{root};
792	local $new = my $state = $self->{state} = {};
793		1045
794	($x, $y, $w, $h) =
795	$self->background_geometry ($self->{border});	1046	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
796		1047
797	# evaluate user expression	1048	# evaluate user expression
798		1049
799	my $img = eval { $self->{expr}->() };	1050	my @img = eval { $self->{expr}->() };
800	warn $@ if $@;#d#	1051	die $@ if $@;
801	die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";	1052	die "background-expr did not return anything.\n" unless @img;
		1053	die "background-expr: expected image(s), got something else.\n"
		1054	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
802		1055
803	$state->{size_sensitive} = 1	1056	my $img = urxvt::bgdsl::merge @img;
		1057
		1058	$frame->[FR_AGAIN]{size} = 1
804	if $img->repeat_mode != urxvt::RepeatNormal;	1059	if $img->repeat_mode != urxvt::RepeatNormal;
805		1060
806	# if the expression is sensitive to external events, prepare reevaluation then	1061	# if the expression is sensitive to external events, prepare reevaluation then
807		1062	$self->compile_frame ($frame, sub { $arg_self->recalculate });
808	my $repeat;
809
810	if (my $again = $state->{again}) {
811	$repeat = 1;
812	my $self = $self;
813	$state->{timer} = $again == $old->{again}
814	? $old->{timer}
815	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
816	++$self->{counter};
817	$self->recalculate
818	});
819	}
820
821	if (delete $state->{position_sensitive}) {
822	$repeat = 1;
823	$self->enable (position_change => sub { $_[0]->recalculate });
824	} else {
825	$self->disable ("position_change");
826	}
827
828	if (delete $state->{size_sensitive}) {
829	$repeat = 1;
830	$self->enable (size_change => sub { $_[0]->recalculate });
831	} else {
832	$self->disable ("size_change");
833	}
834
835	if (delete $state->{rootpmap_sensitive}) {
836	$repeat = 1;
837	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
838	} else {
839	$self->disable ("rootpmap_change");
840	}
841		1063
842	# clear stuff we no longer need	1064	# clear stuff we no longer need
843		1065
844	%$old = ();	1066	# unless (%{ $frame->[FR_STATE] }) {
845
846	unless ($repeat) {
847	delete $self->{state};	1067	# delete $self->{state};
848	delete $self->{expr};	1068	# delete $self->{expr};
849	}	1069	# }
850		1070
851	# set background pixmap	1071	# set background pixmap
852		1072
853	$self->set_background ($img, $self->{border});	1073	$self->set_background ($img, $self->{border});
854	$self->scr_recolour (0);	1074	$self->scr_recolour (0);

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.48 by root, Sun Jun 10 15:01:14 2012 UTC vs. Revision 1.74 by root, Sat Jul 14 08:42:54 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.48 by root, Sun Jun 10 15:01:14 2012 UTC vs.
Revision 1.74 by root, Sat Jul 14 08:42:54 2012 UTC