[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 1.63 by root, Tue Jun 19 18:17:56 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.
57		57
58	For example, an expression such as C<scale load "$HOME/mybg.png"> scales the	58	For example, an expression such as C<scale load "$HOME/mybg.png"> scales the
59	image to the window size, so it relies on the window size and will	59	image to the window size, so it relies on the window size and will
60	be reevaluated each time it is changed, but not when it moves for	60	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:
…		…
71	return scale load "$HOME/weekday.png";	71	return scale load "$HOME/weekday.png";
72	} else {	72	} else {
73	return scale load "$HOME/sunday.png";	73	return scale load "$HOME/sunday.png";
74	}	74	}
75		75
76	This expression gets evaluated once per hour. It will set F<sunday.png> as	76	This expression is evaluated once per hour. It will set F<sunday.png> as
77	background on Sundays, and F<weekday.png> on all other days.	77	background on Sundays, and F<weekday.png> on all other days.
78		78
79	Fortunately, we expect that most expressions will be much simpler, with	79	Fortunately, we expect that most expressions will be much simpler, with
80	little Perl knowledge needed.	80	little Perl knowledge needed.
81		81
…		…
115	horizontal and vertical dimensions. For example, this halves the image	115	horizontal and vertical dimensions. For example, this halves the image
116	width and doubles the image height:	116	width and doubles the image height:
117		117
118	scale 0.5, 2, load "$HOME/mypic.png"	118	scale 0.5, 2, load "$HOME/mypic.png"
119		119
120	Other effects than scalign are also readily available, for exmaple, you can	120	Other effects than scaling are also readily available, for example, you can
121	tile the image to fill the whole window, instead of resizing it:	121	tile the image to fill the whole window, instead of resizing it:
122		122
123	tile load "$HOME/mypic.png"	123	tile load "$HOME/mypic.png"
124		124
125	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator	125	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator
…		…
138	pseudo-transparency, as the image seems to be static while the window is	138	pseudo-transparency, as the image seems to be static while the window is
139	moved around.	139	moved around.
140		140
141	=head2 CYCLES AND CACHING	141	=head2 CYCLES AND CACHING
142		142
		143	=head3 C<load> et al.
		144
143	As has been mentioned before, the expression might be evaluated multiple	145	As has been mentioned before, the expression might be evaluated multiple
144	times. Each time the expression is reevaluated, a new cycle is said to	146	times. Each time the expression is reevaluated, a new cycle is said to
145	have begun. Many operators cache their results till the next cycle.	147	have begun. Many operators cache their results till the next cycle.
146		148
147	For example, the C<load> operator keeps a copy of the image. If it is	149	For example, the C<load> operator keeps a copy of the image. If it is
…		…
151	This only works for one cycle though, so as long as you load the same	153	This only works for one cycle though, so as long as you load the same
152	image every time, it will always be cached, but when you load a different	154	image every time, it will always be cached, but when you load a different
153	image, it will forget about the first one.	155	image, it will forget about the first one.
154		156
155	This allows you to either speed things up by keeping multiple images in	157	This allows you to either speed things up by keeping multiple images in
156	memory, or comserve memory by loading images more often.	158	memory, or conserve memory by loading images more often.
157		159
158	For example, you can keep two images in memory and use a random one like	160	For example, you can keep two images in memory and use a random one like
159	this:	161	this:
160		162
161	my $img1 = load "img1.png";	163	my $img1 = load "img1.png";
…		…
171		173
172	Here, a path is selected randomly, and load is only called for one image,	174	Here, a path is selected randomly, and load is only called for one image,
173	so keeps only one image in memory. If, on the next evaluation, luck	175	so keeps only one image in memory. If, on the next evaluation, luck
174	decides to use the other path, then it will have to load that image again.	176	decides to use the other path, then it will have to load that image again.
175		177
		178	=head3 C<once { ... }>
		179
		180	Another way to cache expensive operations is to use C<once { ... }>. The
		181	C<once> operator takes a block of multiple statements enclosed by C<{}>
		182	and evaluates it only.. once, returning any images the last statement
		183	returned. Further calls simply produce the values from the cache.
		184
		185	This is most useful for expensive operations, such as C<blur>:
		186
		187	rootalign once { blur 20, root }
		188
		189	This makes a blurred copy of the root background once, and on subsequent
		190	calls, just root-aligns it. Since C<blur> is usually quite slow and
		191	C<rootalign> is quite fast, this trades extra memory (For the cached
		192	blurred pixmap) with speed (blur only needs to be redone when root
		193	changes).
		194
176	=head1 REFERENCE	195	=head1 REFERENCE
177		196
178	=head2 COMMAND LINE SWITCHES	197	=head2 COMMAND LINE SWITCHES
179		198
180	=over 4	199	=over 4
…		…
189	overwriting borders and any other areas, such as the scrollbar.	208	overwriting borders and any other areas, such as the scrollbar.
190		209
191	Specifying this flag changes the behaviour, so that the image only	210	Specifying this flag changes the behaviour, so that the image only
192	replaces the background of the character area.	211	replaces the background of the character area.
193		212
		213	=item --background-interval seconds
		214
		215	Since some operations in the underlying XRender extension can effectively
		216	freeze your X-server for prolonged time, this extension enforces a minimum
		217	time between updates, which is normally about 0.1 seconds.
		218
		219	If you want to do updates more often, you can decrease this safety
		220	interval with this switch.
		221
194	=back	222	=back
195		223
196	=cut	224	=cut
197		225
		226	our %_IMG_CACHE;
198	our $HOME;	227	our $HOME;
199	our ($self, $old, $new);	228	our ($self, $frame);
200	our ($x, $y, $w, $h);	229	our ($x, $y, $w, $h);
201		230
202	# enforce at least this interval between updates	231	# enforce at least this interval between updates
203	our $MIN_INTERVAL = 1/100;	232	our $MIN_INTERVAL = 6/59.951;
204		233
205	{	234	{
206	package urxvt::bgdsl; # background language	235	package urxvt::bgdsl; # background language
		236
		237	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
		238	sub FR_CACHE () { 1 } # cached values
		239	sub FR_AGAIN () { 2 } # what this expr is sensitive to
		240	sub FR_STATE () { 3 } # watchers etc.
207		241
208	use List::Util qw(min max sum shuffle);	242	use List::Util qw(min max sum shuffle);
209		243
210	=head2 PROVIDERS/GENERATORS	244	=head2 PROVIDERS/GENERATORS
211		245
…		…
218	=item load $path	252	=item load $path
219		253
220	Loads the image at the given C<$path>. The image is set to plane tiling	254	Loads the image at the given C<$path>. The image is set to plane tiling
221	mode.	255	mode.
222		256
223	Loaded images will be cached for one cycle.	257	Loaded images will be cached for one cycle, and shared between temrinals
		258	running in the same process (e.g. in C<urxvtd>).
		259
		260	#=item load_uc $path
		261	#
		262	#Load uncached - same as load, but does not cache the image. This function
		263	#is most useufl if you want to optimise a background expression in some
		264	#way.
224		265
225	=cut	266	=cut
226		267
227	sub load($) {	268	sub load($) {
228	my ($path) = @_;	269	my ($path) = @_;
229		270
230	$new->{load}{$path} = $old->{load}{$path} \|\| $self->new_img_from_file ($path);	271	$_IMG_CACHE{$path} \|\| do {
		272	my $img = $self->new_img_from_file ($path);
		273	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		274	$img
		275	}
231	}	276	}
232		277
233	=item root	278	=item root
234		279
235	Returns the root window pixmap, that is, hopefully, the background image	280	Returns the root window pixmap, that is, hopefully, the background image
236	of your screen. The image is set to extend mode.	281	of your screen.
237		282
238	This function makes your expression root sensitive, that means it will be	283	This function makes your expression root sensitive, that means it will be
239	reevaluated when the bg image changes.	284	reevaluated when the bg image changes.
240		285
241	=cut	286	=cut
242		287
243	sub root() {	288	sub root() {
244	$new->{rootpmap_sensitive} = 1;	289	$frame->[FR_AGAIN]{rootpmap} = 1;
245	die "root op not supported, exg, we need you";	290	$self->new_img_from_root
246	}	291	}
247		292
248	=item solid $colour	293	=item solid $colour
249		294
250	=item solid $width, $height, $colour	295	=item solid $width, $height, $colour
…		…
258	=cut	303	=cut
259		304
260	sub solid($;$$) {	305	sub solid($;$$) {
261	my $colour = pop;	306	my $colour = pop;
262		307
263	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	308	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
264	$img->fill ($colour);	309	$img->fill ($colour);
265	$img	310	$img
266	}	311	}
267		312
268	=back	313	=item clone $img
269		314
270	=head2 VARIABLES	315	Returns an exact copy of the image. This is useful if you want to have
		316	multiple copies of the same image to apply different effects to.
271		317
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	318	=cut
314		319
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} = $_[0];
348	}
349
350	sub counter($) {	320	sub clone($) {
351	$new->{again} = $_[0];	321	$_[0]->clone
352	$self->{counter} + 0
353	}	322	}
354		323
355	=back	324	=item merge $img ...
		325
		326	Takes any number of images and merges them together, creating a single
		327	image containing them all. The tiling mode of the first image is used as
		328	the tiling mdoe of the resulting image.
		329
		330	This function is called automatically when an expression returns multiple
		331	images.
		332
		333	=cut
		334
		335	sub merge(@) {
		336	return $_[0] unless $#_;
		337
		338	# rather annoyingly clumsy, but optimisation is for another time
		339
		340	my $x0 = +1e9;
		341	my $y0 = +1e9;
		342	my $x1 = -1e9;
		343	my $y1 = -1e9;
		344
		345	for (@_) {
		346	my ($x, $y, $w, $h) = $_->geometry;
		347
		348	$x0 = $x if $x0 > $x;
		349	$y0 = $y if $y0 > $y;
		350
		351	$x += $w;
		352	$y += $h;
		353
		354	$x1 = $x if $x1 < $x;
		355	$y1 = $y if $y1 < $y;
		356	}
		357
		358	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		359	$base->repeat_mode ($_[0]->repeat_mode);
		360	$base->fill ([0, 0, 0, 0]);
		361
		362	$base->draw ($_)
		363	for @_;
		364
		365	$base
		366	}
356		367
357	=head2 TILING MODES	368	=head2 TILING MODES
358		369
359	The following operators modify the tiling mode of an image, that is, the	370	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.	371	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	401	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	402	image over another image or the background colour while leaving all
392	background pixels outside the image unchanged.	403	background pixels outside the image unchanged.
393		404
394	Example: load an image and display it in the upper left corner. The rest	405	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	406	of the space is left "empty" (transparent or whatever your compositor does
396	in alpha mode, else background colour).	407	in alpha mode, else background colour).
397		408
398	pad load "mybg.png"	409	pad load "mybg.png"
399		410
400	=item extend $img	411	=item extend $img
401		412
402	Extends the image over the whole plane, using the closest pixel in the	413	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	414	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	415	filtering operations and want the pixels outside the image to have the
405	same values as the pixels near the edge.	416	same values as the pixels near the edge.
406		417
407	Example: just for curiosity, how does this pixel extension stuff work?	418	Example: just for curiosity, how does this pixel extension stuff work?
408		419
…		…
434	$img	445	$img
435	}	446	}
436		447
437	=back	448	=back
438		449
439	=head2 PIXEL OPERATORS	450	=head2 VARIABLE VALUES
440		451
441	The following operators modify the image pixels in various ways.	452	The following functions provide variable data such as the terminal window
		453	dimensions. They are not (Perl-) variables, they just return stuff that
		454	varies. Most of them make your expression sensitive to some events, for
		455	example using C<TW> (terminal width) means your expression is evaluated
		456	again when the terminal is resized.
442		457
443	=over 4	458	=over 4
444		459
445	=item clone $img	460	=item TX
446		461
447	Returns an exact copy of the image.	462	=item TY
448		463
449	=cut	464	Return the X and Y coordinates of the terminal window (the terminal
		465	window is the full window by default, and the character area only when in
		466	border-respect mode).
450		467
		468	Using these functions make your expression sensitive to window moves.
		469
		470	These functions are mainly useful to align images to the root window.
		471
		472	Example: load an image and align it so it looks as if anchored to the
		473	background.
		474
		475	move -TX, -TY, load "mybg.png"
		476
		477	=item TW
		478
		479	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
		480	terminal window is the full window by default, and the character area only
		481	when in border-respect mode).
		482
		483	Using these functions make your expression sensitive to window resizes.
		484
		485	These functions are mainly useful to scale images, or to clip images to
		486	the window size to conserve memory.
		487
		488	Example: take the screen background, clip it to the window size, blur it a
		489	bit, align it to the window position and use it as background.
		490
		491	clip move -TX, -TY, once { blur 5, root }
		492
		493	=cut
		494
		495	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
		496	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
		497	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
		498	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
		499
		500	=item now
		501
		502	Returns the current time as (fractional) seconds since the epoch.
		503
		504	Using this expression does I<not> make your expression sensitive to time,
		505	but the next two functions do.
		506
		507	=item again $seconds
		508
		509	When this function is used the expression will be reevaluated again in
		510	C<$seconds> seconds.
		511
		512	Example: load some image and rotate it according to the time of day (as if it were
		513	the hour pointer of a clock). Update this image every minute.
		514
		515	again 60; rotate 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
		516
		517	=item counter $seconds
		518
		519	Like C<again>, but also returns an increasing counter value, starting at
		520	0, which might be useful for some simple animation effects.
		521
		522	=cut
		523
		524	sub now() { urxvt::NOW }
		525
		526	sub again($) {
		527	$frame->[FR_AGAIN]{time} = $_[0];
		528	}
		529
451	sub clone($) {	530	sub counter($) {
452	$_[0]->clone	531	$frame->[FR_AGAIN]{time} = $_[0];
		532	$frame->[FR_STATE]{counter} + 0
453	}	533	}
		534
		535	=back
		536
		537	=head2 SHAPE CHANGING OPERATORS
		538
		539	The following operators modify the shape, size or position of the image.
		540
		541	=over 4
454		542
455	=item clip $img	543	=item clip $img
456		544
457	=item clip $width, $height, $img	545	=item clip $width, $height, $img
458		546
…		…
552		640
553	Example: move the image right by 20 pixels and down by 30.	641	Example: move the image right by 20 pixels and down by 30.
554		642
555	move 20, 30, ...	643	move 20, 30, ...
556		644
		645	=item align $xalign, $yalign, $img
		646
		647	Aligns the image according to a factor - C<0> means the image is moved to
		648	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		649	exactly centered and C<1> means it touches the right or bottom edge.
		650
		651	Example: remove any visible border around an image, center it vertically but move
		652	it to the right hand side.
		653
		654	align 1, 0.5, pad $img
		655
		656	=item center $img
		657
		658	=item center $width, $height, $img
		659
		660	Centers the image, i.e. the center of the image is moved to the center of
		661	the terminal window (or the box specified by C<$width> and C<$height> if
		662	given).
		663
		664	Example: load an image and center it.
		665
		666	center pad load "mybg.png"
		667
557	=item rootalign $img	668	=item rootalign $img
558		669
559	Moves the image so that it appears glued to the screen as opposed to the	670	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	671	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	672	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
…		…
566	rootalign mirror load "mybg.png"	677	rootalign mirror load "mybg.png"
567		678
568	Example: take the screen background and align it, giving the illusion of	679	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.	680	transparency as long as the window isn't in front of other windows.
570		681
571	rootalign root	682	rootalign root
572		683
573	=cut	684	=cut
574		685
575	sub move($$;$) {	686	sub move($$;$) {
576	my $img = pop->clone;	687	my $img = pop->clone;
577	$img->move ($_[0], $_[1]);	688	$img->move ($_[0], $_[1]);
578	$img	689	$img
579	}	690	}
580		691
		692	sub align($;$$) {
		693	my $img = pop;
		694
		695	move $_[0] * (TW - $img->w),
		696	$_[1] * (TH - $img->h),
		697	$img
		698	}
		699
		700	sub center($;$$) {
		701	my $img = pop;
		702	my $w = $_[0] \|\| TW;
		703	my $h = $_[1] \|\| TH;
		704
		705	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		706	}
		707
581	sub rootalign($) {	708	sub rootalign($) {
582	move -TX, -TY, $_[0]	709	move -TX, -TY, $_[0]
583	}	710	}
584		711
		712	=item rotate $center_x, $center_y, $degrees
		713
		714	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
		715	pointer at C<$center_x> and C<$center_y> (specified as factor of image
		716	width/height).
		717
		718	#TODO# new width, height, maybe more operators?
		719
		720	Example: rotate the image by 90 degrees
		721
		722	=cut
		723
		724	sub rotate($$$$) {
		725	my $img = pop;
		726	$img->rotate (
		727	$_[0] * ($img->w + $img->x),
		728	$_[1] * ($img->h + $img->y),
		729	$_[2] * (3.14159265 / 180),
		730	)
		731	}
		732
		733	=back
		734
		735	=head2 COLOUR MODIFICATIONS
		736
		737	The following operators change the pixels of the image.
		738
		739	=over 4
		740
585	=item contrast $factor, $img	741	=item contrast $factor, $img
586		742
587	=item contrast $r, $g, $b, $img	743	=item contrast $r, $g, $b, $img
588		744
589	=item contrast $r, $g, $b, $a, $img	745	=item contrast $r, $g, $b, $a, $img
590		746
591	Adjusts the I<contrast> of an image.	747	Adjusts the I<contrast> of an image.
592		748
593	#TODO#	749	The first form applies a single C<$factor> to red, green and blue, the
		750	second form applies separate factors to each colour channel, and the last
		751	form includes the alpha channel.
594		752
		753	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		754	contrast.
		755
		756	Due to limitations in the underlying XRender extension, lowering contrast
		757	also reduces brightness, while increasing contrast currently also
		758	increases brightness.
		759
595	=item brightness $factor, $img	760	=item brightness $bias, $img
596		761
597	=item brightness $r, $g, $b, $img	762	=item brightness $r, $g, $b, $img
598		763
599	=item brightness $r, $g, $b, $a, $img	764	=item brightness $r, $g, $b, $a, $img
600		765
601	Adjusts the brightness of an image.	766	Adjusts the brightness of an image.
		767
		768	The first form applies a single C<$bias> to red, green and blue, the
		769	second form applies separate biases to each colour channel, and the last
		770	form includes the alpha channel.
		771
		772	Values less than 0 reduce brightness, while values larger than 0 increase
		773	it. Useful range is from -1 to 1 - the former results in a black, the
		774	latter in a white picture.
		775
		776	Due to idiosyncrasies in the underlying XRender extension, biases less
		777	than zero can be I<very> slow.
602		778
603	=cut	779	=cut
604		780
605	sub contrast($$;$$;$) {	781	sub contrast($$;$$;$) {
606	my $img = pop;	782	my $img = pop;
607	my ($r, $g, $b, $a) = @_;	783	my ($r, $g, $b, $a) = @_;
608		784
609	($g, $b) = ($r, $r) if @_ < 4;	785	($g, $b) = ($r, $r) if @_ < 3;
610	$a = 1 if @_ < 5;	786	$a = 1 if @_ < 4;
611		787
612	$img = $img->clone;	788	$img = $img->clone;
613	$img->contrast ($r, $g, $b, $a);	789	$img->contrast ($r, $g, $b, $a);
614	$img	790	$img
615	}	791	}
616		792
617	sub brightness($$;$$;$) {	793	sub brightness($$;$$;$) {
618	my $img = pop;	794	my $img = pop;
619	my ($r, $g, $b, $a) = @_;	795	my ($r, $g, $b, $a) = @_;
620		796
621	($g, $b) = ($r, $r) if @_ < 4;	797	($g, $b) = ($r, $r) if @_ < 3;
622	$a = 1 if @_ < 5;	798	$a = 1 if @_ < 4;
623		799
624	$img = $img->clone;	800	$img = $img->clone;
625	$img->brightness ($r, $g, $b, $a);	801	$img->brightness ($r, $g, $b, $a);
626	$img	802	$img
627	}	803	}
…		…
643	sub blur($$;$) {	819	sub blur($$;$) {
644	my $img = pop;	820	my $img = pop;
645	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	821	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
646	}	822	}
647		823
648	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
649
650	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
651	pointer at C<$center_x> and C<$center_y> (specified as factor of image
652	width/height), generating a new image with width C<$new_width> and height
653	C<$new_height>.
654
655	#TODO# new width, height, maybe more operators?
656
657	Example: rotate the image by 90 degrees
658
659	=cut
660
661	sub rotate($$$$$$) {
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	824	=back
673		825
		826	=head2 OTHER STUFF
		827
		828	Anything that didn't fit any of the other categories, even after applying
		829	force and closing our eyes.
		830
		831	=over 4
		832
		833	=item once { ... }
		834
		835	This function takes a code block as argument, that is, one or more
		836	statements enclosed by braces.
		837
		838	The trick is that this code block is only evaluated once - future calls
		839	will simply return the original image (yes, it should only be used with
		840	images).
		841
		842	This can be extremely useful to avoid redoing the same slow operations
		843	again and again- for example, if your background expression takes the root
		844	background, blurs it and then root-aligns it it would have to blur the
		845	root background on every window move or resize.
		846
		847	In fact, urxvt itself encloses the whole expression in some kind of
		848	C<once> block so it only is reevaluated as required.
		849
		850	Putting the blur into a C<once> block will make sure the blur is only done
		851	once:
		852
		853	rootlign once { blur 10, root }
		854
		855	This leaves the question of how to force reevaluation of the block,
		856	in case the root background changes: If expression inside the block
		857	is sensitive to some event (root background changes, window geometry
		858	changes), then it will be reevaluated automatically as needed.
		859
		860	=item once_again
		861
		862	Resets all C<once> block as if they had never been called, i.e. on the
		863	next call they will be reevaluated again.
		864
		865	=cut
		866
		867	sub once(&) {
		868	my $id = $_[0]+0;
		869
		870	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		871
		872	unless ($frame->[FR_CACHE]) {
		873	$frame->[FR_CACHE] = [ $_[0]() ];
		874
		875	my $self = $self;
		876	my $frame = $frame;
		877	Scalar::Util::weaken $frame;
		878	$self->compile_frame ($frame, sub {
		879	# clear this frame cache, also for all parents
		880	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		881	undef $frame->[FR_CACHE];
		882	}
		883
		884	unless ($self->{term}) {
		885	use Data::Dump;
		886	ddx $frame;
		887	exit;
		888	}
		889
		890	$self->recalculate;
		891	});
		892	};
		893
		894	# in scalar context we always return the first original result, which
		895	# is not quite how perl works.
		896	wantarray
		897	? @{ $frame->[FR_CACHE] }
		898	: $frame->[FR_CACHE][0]
		899	}
		900
		901	sub once_again() {
		902	delete $self->{frame_cache};
		903	}
		904
		905	=back
		906
674	=cut	907	=cut
675		908
676	}	909	}
677		910
678	sub parse_expr {	911	sub parse_expr {
679	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	912	my $expr = eval
		913	"sub {\n"
		914	. "package urxvt::bgdsl;\n"
		915	. "#line 0 'background expression'\n"
		916	. "$_[0]\n"
		917	. "}";
680	die if $@;	918	die if $@;
681	$expr	919	$expr
682	}	920	}
683		921
684	# compiles a parsed expression	922	# compiles a parsed expression
685	sub set_expr {	923	sub set_expr {
686	my ($self, $expr) = @_;	924	my ($self, $expr) = @_;
687		925
		926	$self->{root} = [];
688	$self->{expr} = $expr;	927	$self->{expr} = $expr;
689	$self->recalculate;	928	$self->recalculate;
		929	}
		930
		931	# takes a hash of sensitivity indicators and installs watchers
		932	sub compile_frame {
		933	my ($self, $frame, $cb) = @_;
		934
		935	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		936	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		937
		938	# don't keep stuff alive
		939	Scalar::Util::weaken $state;
		940
		941	if ($again->{nested}) {
		942	$state->{nested} = 1;
		943	} else {
		944	delete $state->{nested};
		945	}
		946
		947	if (my $interval = $again->{time}) {
		948	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		949	if $state->{time}[0] != $interval;
		950
		951	# callback might have changed, although we could just rule that out
		952	$state->{time}[1]->cb (sub {
		953	++$state->{counter};
		954	$cb->();
		955	});
		956	} else {
		957	delete $state->{time};
		958	}
		959
		960	if ($again->{position}) {
		961	$state->{position} = $self->on (position_change => $cb);
		962	} else {
		963	delete $state->{position};
		964	}
		965
		966	if ($again->{size}) {
		967	$state->{size} = $self->on (size_change => $cb);
		968	} else {
		969	delete $state->{size};
		970	}
		971
		972	if ($again->{rootpmap}) {
		973	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		974	} else {
		975	delete $state->{rootpmap};
		976	}
690	}	977	}
691		978
692	# evaluate the current bg expression	979	# evaluate the current bg expression
693	sub recalculate {	980	sub recalculate {
694	my ($arg_self) = @_;	981	my ($arg_self) = @_;
…		…
704		991
705	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	992	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
706		993
707	# set environment to evaluate user expression	994	# set environment to evaluate user expression
708		995
709	local $self = $arg_self;	996	local $self = $arg_self;
710
711	local $HOME = $ENV{HOME};	997	local $HOME = $ENV{HOME};
712	local $old = $self->{state};	998	local $frame = [];
713	local $new = my $state = $self->{state} = {};
714		999
715	($x, $y, $w, $h) =
716	$self->background_geometry ($self->{border});	1000	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
717		1001
718	# evaluate user expression	1002	# evaluate user expression
719		1003
720	my $img = eval { $self->{expr}->() };	1004	my @img = eval { $self->{expr}->() };
721	warn $@ if $@;#d#	1005	die $@ if $@;
		1006	die "background-expr did not return anything.\n" unless @img;
		1007	die "background-expr: expected image(s), got something else.\n"
722	die if !UNIVERSAL::isa $img, "urxvt::img";	1008	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
723		1009
724	$state->{size_sensitive} = 1	1010	my $img = urxvt::bgdsl::merge @img;
		1011
		1012	$frame->[FR_AGAIN]{size} = 1
725	if $img->repeat_mode != urxvt::RepeatNormal;	1013	if $img->repeat_mode != urxvt::RepeatNormal;
726		1014
727	# if the expression is sensitive to external events, prepare reevaluation then	1015	# if the expression is sensitive to external events, prepare reevaluation then
728		1016	$self->compile_frame ($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	$self->disable ("rootpmap_change");
761	}
762		1017
763	# clear stuff we no longer need	1018	# clear stuff we no longer need
764		1019
765	%$old = ();	1020	# unless (%{ $frame->[FR_STATE] }) {
766
767	unless ($repeat) {
768	delete $self->{state};	1021	# delete $self->{state};
769	delete $self->{expr};	1022	# delete $self->{expr};
770	}	1023	# }
771		1024
772	# set background pixmap	1025	# set background pixmap
773		1026
774	$self->set_background ($img, $self->{border});	1027	$self->set_background ($img, $self->{border});
775	$self->scr_recolour (0);	1028	$self->scr_recolour (0);
…		…
777	}	1030	}
778		1031
779	sub on_start {	1032	sub on_start {
780	my ($self) = @_;	1033	my ($self) = @_;
781		1034
782	my $expr = $self->x_resource ("background.expr")	1035	my $expr = $self->x_resource ("%.expr")
783	or return;	1036	or return;
784		1037
		1038	$self->has_render
		1039	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		1040
785	$self->set_expr (parse_expr $expr);	1041	$self->set_expr (parse_expr $expr);
786	$self->{border} = $self->x_resource_boolean ("background.border");	1042	$self->{border} = $self->x_resource_boolean ("%.border");
		1043
		1044	$MIN_INTERVAL = $self->x_resource ("%.interval");
787		1045
788	()	1046	()
789	}	1047	}
790		1048

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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 1.63 by root, Tue Jun 19 18:17:56 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 1.63 by root, Tue Jun 19 18:17:56 2012 UTC