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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.35 by root, Fri Jun 8 08:06:38 2012 UTC vs.
Revision 1.44 by root, Sun Jun 10 11:31:22 2012 UTC

…		…
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
6	#TODO: once, rootalign	6	#TODO: once, rootalign
7		7
		8	=head1 NAME
		9
8	=head1 background - manage terminal background	10	background - manage terminal background
9		11
10	=head2 SYNOPSIS	12	=head1 SYNOPSIS
11		13
12	rxvt -background-expr 'background expression'	14	urxvt --background-expr 'background expression'
13	-background-border	15	--background-border
14		16
15	=head2 DESCRIPTION	17	=head1 DESCRIPTION
16		18
		19	This extension manages the terminal background by creating a picture that
		20	is behind the text, replacing the normal background colour.
		21
		22	It does so by evaluating a Perl expression that I<calculates> the image on
		23	the fly, for example, by grabbing the root background or loading a file.
		24
		25	While the full power of Perl is available, the operators have been design
		26	to be as simple as possible.
		27
		28	For example, to load an image and scale it to the window size, you would
		29	use:
		30
		31	urxvt --background-expr 'scale load "/path/to/mybg.png"'
		32
		33	Or specified as a X resource:
		34
		35	URxvt.background-expr: scale load "/path/to/mybg.png"
		36
		37	=head1 THEORY OF OPERATION
		38
		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
		41	extended as necessary to cover the whole terminal window, and is set as a
		42	background pixmap.
		43
		44	If the image contains an alpha channel, then it will be used as-is in
		45	visuals that support alpha channels (for example, for a compositing
		46	manager). In other visuals, the terminal background colour will be used to
		47	replace any transparency.
		48
		49	When the expression relies, directly or indirectly, on the window size,
		50	position, the root pixmap, or a timer, then it will be remembered. If not,
		51	then it will be removed.
		52
		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
		55	pixmap is replaced by another one the root background changes; or when the
		56	timer elapses), then the expression will be evaluated again.
		57
		58	For example, an expression such as C<scale load "$HOME/mybg.png"> scales the
		59	image to the window size, so it relies on the window size and will
		60	be reevaluated each time it is changed, but not when it moves for
		61	example. That ensures that the picture always fills the terminal, even
		62	after it's size changes.
		63
		64	=head2 EXPRESSIONS
		65
		66	Expressions are normal Perl expressions, in fact, they are Perl blocks -
		67	which means you could use multiple lines and statements:
		68
		69	again 3600;
		70	if (localtime now)[6]) {
		71	return scale load "$HOME/weekday.png";
		72	} else {
		73	return scale load "$HOME/sunday.png";
		74	}
		75
		76	This expression gets evaluated once per hour. It will set F<sunday.png> as
		77	background on Sundays, and F<weekday.png> on all other days.
		78
		79	Fortunately, we expect that most expressions will be much simpler, with
		80	little Perl knowledge needed.
		81
		82	Basically, you always start with a function that "generates" an image
		83	object, such as C<load>, which loads an image from disk, or C<root>, which
		84	returns the root window background image:
		85
		86	load "$HOME/mypic.png"
		87
		88	The path is usually specified as a quoted string (the exact rules can be
		89	found in the L<perlop> manpage). The F<$HOME> at the beginning of the
		90	string is expanded to the home directory.
		91
		92	Then you prepend one or more modifiers or filtering expressions, such as
		93	C<scale>:
		94
		95	scale load "$HOME/mypic.png"
		96
		97	Just like a mathematical expression with functions, you should read these
		98	expressions from right to left, as the C<load> is evaluated first, and
		99	its result becomes the argument to the C<scale> function.
		100
		101	Many operators also allow some parameters preceding the input image
		102	that modify its behaviour. For example, C<scale> without any additional
		103	arguments scales the image to size of the terminal window. If you specify
		104	an additional argument, it uses it as a scale factor (multiply by 100 to
		105	get a percentage):
		106
		107	scale 2, load "$HOME/mypic.png"
		108
		109	This enlarges the image by a factor of 2 (200%). As you can see, C<scale>
		110	has now two arguments, the C<200> and the C<load> expression, while
		111	C<load> only has one argument. Arguments are separated from each other by
		112	commas.
		113
		114	Scale also accepts two arguments, which are then separate factors for both
		115	horizontal and vertical dimensions. For example, this halves the image
		116	width and doubles the image height:
		117
		118	scale 0.5, 2, load "$HOME/mypic.png"
		119
		120	Other effects than scalign are also readily available, for exmaple, you can
		121	tile the image to fill the whole window, instead of resizing it:
		122
		123	tile load "$HOME/mypic.png"
		124
		125	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator
		126	is kind of superfluous.
		127
		128	Another common effect is to mirror the image, so that the same edges touch:
		129
		130	mirror load "$HOME/mypic.png"
		131
		132	This is also a typical background expression:
		133
		134	rootalign root
		135
		136	It 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
		138	pseudo-transparency, as the image seems to be static while the window is
		139	moved around.
		140
		141	=head2 CYCLES AND CACHING
		142
		143	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
		145	have begun. Many operators cache their results till the next cycle.
		146
		147	For example, the C<load> operator keeps a copy of the image. If it is
		148	asked to load the same image on the next cycle it will not load it again,
		149	but return the cached copy.
		150
		151	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
		153	image, it will forget about the first one.
		154
		155	This allows you to either speed things up by keeping multiple images in
		156	memory, or comserve memory by loading images more often.
		157
		158	For example, you can keep two images in memory and use a random one like
		159	this:
		160
		161	my $img1 = load "img1.png";
		162	my $img2 = load "img2.png";
		163	(0.5 > rand) ? $img1 : $img2
		164
		165	Since both images are "loaded" every time the expression is evaluated,
		166	they are always kept in memory. Contrast this version:
		167
		168	my $path1 = "img1.png";
		169	my $path2 = "img2.png";
		170	load ((0.5 > rand) ? $path1 : $path2)
		171
		172	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
		174	decides to use the other path, then it will have to load that image again.
		175
17	=head2 REFERENCE	176	=head1 REFERENCE
18		177
19	=cut	178	=head2 COMMAND LINE SWITCHES
20		179
21	our $EXPR;	180	=over 4
22	#$EXPR = 'move W * 0.1, -H * 0.1, resize W * 0.5, H * 0.5, repeat_none load "opensource.png"';
23	$EXPR = 'move -TX, -TY, load "argb.png"';
24	#$EXPR = '
25	# rotate W, H, 50, 50, counter 1/59.95, repeat_mirror,
26	# clip X, Y, W, H, repeat_mirror,
27	# load "/root/pix/das_fette_schwein.jpg"
28	#';
29	#$EXPR = 'solid "red"';
30	#$EXPR = 'blur root, 10, 10'
31	#$EXPR = 'blur move (root, -x, -y), 5, 5'
32	#resize load "/root/pix/das_fette_schwein.jpg", w, h
33		181
		182	=item --background-expr perl-expression
		183
		184	Specifies the Perl expression to evaluate.
		185
		186	=item --background-border
		187
		188	By default, the expression creates an image that fills the full window,
		189	overwriting borders and any other areas, such as the scrollbar.
		190
		191	Specifying this flag changes the behaviour, so that the image only
		192	replaces the background of the character area.
		193
		194	=back
		195
		196	=cut
		197
		198	our $HOME;
34	our ($self, $old, $new);	199	our ($self, $old, $new);
35	our ($x, $y, $w, $h);	200	our ($x, $y, $w, $h);
36		201
37	# enforce at least this interval between updates	202	# enforce at least this interval between updates
38	our $MIN_INTERVAL = 1/100;	203	our $MIN_INTERVAL = 1/100;
39		204
40	{	205	{
41	package urxvt::bgdsl; # background language	206	package urxvt::bgdsl; # background language
		207
		208	use List::Util qw(min max sum shuffle);
42		209
43	=head2 PROVIDERS/GENERATORS	210	=head2 PROVIDERS/GENERATORS
44		211
45	These functions provide an image, by loading it from disk, grabbing it	212	These functions provide an image, by loading it from disk, grabbing it
46	from the root screen or by simply generating it. They are used as starting	213	from the root screen or by simply generating it. They are used as starting
…		…
83	=item solid $width, $height, $colour	250	=item solid $width, $height, $colour
84		251
85	Creates a new image and completely fills it with the given colour. The	252	Creates a new image and completely fills it with the given colour. The
86	image is set to tiling mode.	253	image is set to tiling mode.
87		254
88	If <$width> and C<$height> are omitted, it creates a 1x1 image, which is	255	If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
89	useful for solid backgrounds or for use in filtering effects.	256	useful for solid backgrounds or for use in filtering effects.
90		257
91	=cut	258	=cut
92		259
93	sub solid($$;$) {	260	sub solid($;$$) {
94	my $colour = pop;	261	my $colour = pop;
95		262
96	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	263	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);
97	$img->fill ($colour);	264	$img->fill ($colour);
98	$img	265	$img
…		…
100		267
101	=back	268	=back
102		269
103	=head2 VARIABLES	270	=head2 VARIABLES
104		271
105	The following functions provide variable data such as the terminal	272	The following functions provide variable data such as the terminal window
		273	dimensions. They are not (Perl-) variables, they jsut return stuff that
106	window dimensions. Most of them make your expression sensitive to some	274	varies. Most of them make your expression sensitive to some events, for
107	events, for example using C<TW> (terminal width) means your expression is	275	example using C<TW> (terminal width) means your expression is evaluated
108	evaluated again when the terminal is resized.	276	again when the terminal is resized.
109		277
110	=over 4	278	=over 4
111		279
112	=item TX	280	=item TX
113		281
…		…
160		328
161	When this function is used the expression will be reevaluated again in	329	When this function is used the expression will be reevaluated again in
162	C<$seconds> seconds.	330	C<$seconds> seconds.
163		331
164	Example: load some image and rotate it according to the time of day (as if it were	332	Example: load some image and rotate it according to the time of day (as if it were
165	the hour pointer of a clock). update this image every minute.	333	the hour pointer of a clock). Update this image every minute.
166		334
167	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"	335	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
168		336
169	=item counter $seconds	337	=item counter $seconds
170		338
…		…
209	Similar to tile, but reflects the image each time it uses a new copy, so	377	Similar to tile, but reflects the image each time it uses a new copy, so
210	that top edges always touch top edges, right edges always touch right	378	that top edges always touch top edges, right edges always touch right
211	edges and so on (with normal tiling, left edges always touch right edges	379	edges and so on (with normal tiling, left edges always touch right edges
212	and top always touch bottom edges).	380	and top always touch bottom edges).
213		381
214	Exmaple: load an image and mirror it over the background, avoiding sharp	382	Example: load an image and mirror it over the background, avoiding sharp
215	edges at the image borders at the expense of mirroring the image itself	383	edges at the image borders at the expense of mirroring the image itself
216		384
217	mirror load "mybg.png"	385	mirror load "mybg.png"
218		386
219	=item pad $img	387	=item pad $img
…		…
221	Takes an image and modifies it so that all pixels outside the image area	389	Takes an image and modifies it so that all pixels outside the image area
222	become transparent. This mode is most useful when you want to place an	390	become transparent. This mode is most useful when you want to place an
223	image over another image or the background colour while leaving all	391	image over another image or the background colour while leaving all
224	background pixels outside the image unchanged.	392	background pixels outside the image unchanged.
225		393
226	Example: load an image and display it in the upper left corner. The rets	394	Example: load an image and display it in the upper left corner. The rest
227	of the space is left "empty" (transparent or wahtever your compisotr does	395	of the space is left "empty" (transparent or wahtever your compisotr does
228	in alpha mode, else background colour).	396	in alpha mode, else background colour).
229		397
230	pad load "mybg.png"	398	pad load "mybg.png"
231		399
…		…
314	$img->sub_rect ($_[0], $_[1], $w, $h)	482	$img->sub_rect ($_[0], $_[1], $w, $h)
315	}	483	}
316		484
317	=item scale $img	485	=item scale $img
318		486
319	=item scale $size_percent, $img	487	=item scale $size_factor, $img
320		488
321	=item scale $width_percent, $height_percent, $img	489	=item scale $width_factor, $height_factor, $img
322		490
323	Scales the image by the given percentages in horizontal	491	Scales the image by the given factors in horizontal
324	(C<$width_percent>) and vertical (C<$height_percent>) direction.	492	(C<$width>) and vertical (C<$height>) direction.
325		493
326	If only one percentage is give, it is used for both directions.	494	If only one factor is give, it is used for both directions.
327		495
328	If no percentages are given, scales the image to the window size without	496	If no factors are given, scales the image to the window size without
329	keeping aspect.	497	keeping aspect.
330		498
331	=item resize $width, $height, $img	499	=item resize $width, $height, $img
332		500
333	Resizes the image to exactly C<$width> times C<$height> pixels.	501	Resizes the image to exactly C<$width> times C<$height> pixels.
334		502
335	=cut	503	=item fit $img
336		504
337	#TODO: maximise, maximise_fill?	505	=item fit $width, $height, $img
		506
		507	Fits the image into the given C<$width> and C<$height> without changing
		508	aspect, or the terminal size. That means it will be shrunk or grown until
		509	the whole image fits into the given area, possibly leaving borders.
		510
		511	=item cover $img
		512
		513	=item cover $width, $height, $img
		514
		515	Similar to C<fit>, but shrinks or grows until all of the area is covered
		516	by the image, so instead of potentially leaving borders, it will cut off
		517	image data that doesn't fit.
		518
		519	=cut
338		520
339	sub scale($;$;$) {	521	sub scale($;$;$) {
340	my $img = pop;	522	my $img = pop;
341		523
342	@_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01)	524	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
343	: @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01)	525	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
344	: $img->scale (TW, TH)	526	: $img->scale (TW, TH)
345	}	527	}
346		528
347	sub resize($$$) {	529	sub resize($$$) {
348	my $img = pop;	530	my $img = pop;
349	$img->scale ($_[0], $_[1])	531	$img->scale ($_[0], $_[1])
350	}	532	}
		533
		534	sub fit($;$$) {
		535	my $img = pop;
		536	my $w = ($_[0] \|\| TW) / $img->w;
		537	my $h = ($_[1] \|\| TH) / $img->h;
		538	scale +(min $w, $h), $img
		539	}
		540
		541	sub cover($;$$) {
		542	my $img = pop;
		543	my $w = ($_[0] \|\| TW) / $img->w;
		544	my $h = ($_[1] \|\| TH) / $img->h;
		545	scale +(max $w, $h), $img
		546	}
		547
		548	=item move $dx, $dy, $img
		549
		550	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
		551	the vertical.
		552
		553	Example: move the image right by 20 pixels and down by 30.
		554
		555	move 20, 30, ...
		556
		557	=item center $img
		558
		559	=item center $width, $height, $img
		560
		561	Centers the image, i.e. the center of the image is moved to the center of
		562	the terminal window (or the box specified by C<$width> and C<$height> if
		563	given).
		564
		565	=item rootalign $img
		566
		567	Moves the image so that it appears glued to the screen as opposed to the
		568	window. This gives the illusion of a larger area behind the window. It is
		569	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
		570	top left of the screen.
		571
		572	Example: load a background image, put it in mirror mode and root align it.
		573
		574	rootalign mirror load "mybg.png"
		575
		576	Example: take the screen background and align it, giving the illusion of
		577	transparency as long as the window isn't in front of other windows.
		578
		579	rootalign root
		580
		581	=cut
351		582
352	sub move($$;$) {	583	sub move($$;$) {
353	my $img = pop->clone;	584	my $img = pop->clone;
354	$img->move ($_[0], $_[1]);	585	$img->move ($_[0], $_[1]);
355	$img	586	$img
356	}	587	}
357		588
		589	sub center($;$$) {
		590	my $img = pop;
		591	my $w = $_[0] \|\| TW;
		592	my $h = $_[0] \|\| TH;
		593
		594	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		595	}
		596
		597	sub rootalign($) {
		598	move -TX, -TY, $_[0]
		599	}
		600
		601	=item contrast $factor, $img
		602
		603	=item contrast $r, $g, $b, $img
		604
		605	=item contrast $r, $g, $b, $a, $img
		606
		607	Adjusts the I<contrast> of an image.
		608
		609	#TODO#
		610
		611	=item brightness $factor, $img
		612
		613	=item brightness $r, $g, $b, $img
		614
		615	=item brightness $r, $g, $b, $a, $img
		616
		617	Adjusts the brightness of an image.
		618
		619	=cut
		620
		621	sub contrast($$;$$;$) {
		622	my $img = pop;
		623	my ($r, $g, $b, $a) = @_;
		624
		625	($g, $b) = ($r, $r) if @_ < 4;
		626	$a = 1 if @_ < 5;
		627
		628	$img = $img->clone;
		629	$img->contrast ($r, $g, $b, $a);
		630	$img
		631	}
		632
		633	sub brightness($$;$$;$) {
		634	my $img = pop;
		635	my ($r, $g, $b, $a) = @_;
		636
		637	($g, $b) = ($r, $r) if @_ < 4;
		638	$a = 1 if @_ < 5;
		639
		640	$img = $img->clone;
		641	$img->brightness ($r, $g, $b, $a);
		642	$img
		643	}
		644
		645	=item blur $radius, $img
		646
		647	=item blur $radius_horz, $radius_vert, $img
		648
		649	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
		650	can also be specified separately.
		651
		652	Blurring is often I<very> slow, at least compared or other
		653	operators. Larger blur radii are slower than smaller ones, too, so if you
		654	don't want to freeze your screen for long times, start experimenting with
		655	low values for radius (<5).
		656
		657	=cut
		658
		659	sub blur($$;$) {
		660	my $img = pop;
		661	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
		662	}
		663
		664	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
		665
		666	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
		667	pointer at C<$center_x> and C<$center_y> (specified as factor of image
		668	width/height), generating a new image with width C<$new_width> and height
		669	C<$new_height>.
		670
		671	#TODO# new width, height, maybe more operators?
		672
		673	Example: rotate the image by 90 degrees
		674
		675	=cut
		676
358	sub rotate($$$$$$) {	677	sub rotate($$$$$$) {
359	my $img = pop;	678	my $img = pop;
360	$img->rotate (	679	$img->rotate (
361	$_[0],	680	$_[0],
362	$_[1],	681	$_[1],
363	$_[2] * $img->w * .01,	682	$_[2] * $img->w,
364	$_[3] * $img->h * .01,	683	$_[3] * $img->h,
365	$_[4] * (3.14159265 / 180),	684	$_[4] * (3.14159265 / 180),
366	)	685	)
367	}
368
369	sub blur($$;$) {
370	my $img = pop;
371	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
372	}
373
374	sub contrast($$;$$;$) {
375	my $img = pop;
376	my ($r, $g, $b, $a) = @_;
377
378	($g, $b) = ($r, $r) if @_ < 4;
379	$a = 1 if @_ < 5;
380
381	$img = $img->clone;
382	$img->contrast ($r, $g, $b, $a);
383	$img
384	}
385
386	sub brightness($$;$$;$) {
387	my $img = pop;
388	my ($r, $g, $b, $a) = @_;
389
390	($g, $b) = ($r, $r) if @_ < 4;
391	$a = 1 if @_ < 5;
392
393	$img = $img->clone;
394	$img->brightness ($r, $g, $b, $a);
395	$img
396	}	686	}
397		687
398	=back	688	=back
399		689
400	=cut	690	=cut
…		…
432		722
433	# set environment to evaluate user expression	723	# set environment to evaluate user expression
434		724
435	local $self = $arg_self;	725	local $self = $arg_self;
436		726
		727	local $HOME = $ENV{HOME};
437	local $old = $self->{state};	728	local $old = $self->{state};
438	local $new = my $state = $self->{state} = {};	729	local $new = my $state = $self->{state} = {};
439		730
440	($x, $y, $w, $h) =	731	($x, $y, $w, $h) =
441	$self->background_geometry ($self->{border});	732	$self->background_geometry ($self->{border});

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.35 by root, Fri Jun 8 08:06:38 2012 UTC vs. Revision 1.44 by root, Sun Jun 10 11:31:22 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.35 by root, Fri Jun 8 08:06:38 2012 UTC vs.
Revision 1.44 by root, Sun Jun 10 11:31:22 2012 UTC