[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 1.41 by root, Fri Jun 8 22:21:48 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 percentage:
		105
		106	scale 200, load "$HOME/mypic.png"
		107
		108	This enlarges the image by a factor of 2 (200%). As you can see, C<scale>
		109	has now two arguments, the C<200> and the C<load> expression, while
		110	C<load> only has one argument. Arguments are separated from each other by
		111	commas.
		112
		113	Scale also accepts two arguments, which are then separate factors for both
		114	horizontal and vertical dimensions. For example, this halves the image
		115	width and doubles the image height:
		116
		117	scale 50, 200, load "$HOME/mypic.png"
		118
		119	Other effects than scalign are also readily available, for exmaple, you can
		120	tile the image to fill the whole window, instead of resizing it:
		121
		122	tile load "$HOME/mypic.png"
		123
		124	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator
		125	is kind of superfluous.
		126
		127	Another common effect is to mirror the image, so that the same edges touch:
		128
		129	mirror load "$HOME/mypic.png"
		130
		131	This is also a typical background expression:
		132
		133	rootalign root
		134
		135	It first takes a snapshot of the screen background image, and then
		136	moves it to the upper left corner of the screen - the result is
		137	pseudo-transparency, as the image seems to be static while the window is
		138	moved around.
		139
		140	=head2 CYCLES AND CACHING
		141
		142	As has been mentioned before, the expression might be evaluated multiple
		143	times. Each time the expression is reevaluated, a new cycle is said to
		144	have begun. Many operators cache their results till the next cycle.
		145
		146	For example, the C<load> operator keeps a copy of the image. If it is
		147	asked to load the same image on the next cycle it will not load it again,
		148	but return the cached copy.
		149
		150	This only works for one cycle though, so as long as you load the same
		151	image every time, it will always be cached, but when you load a different
		152	image, it will forget about the first one.
		153
		154	This allows you to either speed things up by keeping multiple images in
		155	memory, or comserve memory by loading images more often.
		156
		157	For example, you can keep two images in memory and use a random one like
		158	this:
		159
		160	my $img1 = load "img1.png";
		161	my $img2 = load "img2.png";
		162	(0.5 > rand) ? $img1 : $img2
		163
		164	Since both images are "loaded" every time the expression is evaluated,
		165	they are always kept in memory. Contrast this version:
		166
		167	my $path1 = "img1.png";
		168	my $path2 = "img2.png";
		169	load ((0.5 > rand) ? $path1 : $path2)
		170
		171	Here, a path is selected randomly, and load is only called for one image,
		172	so keeps only one image in memory. If, on the next evaluation, luck
		173	decides to use the other path, then it will have to load that image again.
		174
17	=head2 REFERENCE	175	=head1 REFERENCE
18		176
19	=cut	177	=head2 COMMAND LINE SWITCHES
20		178
21	our $EXPR;	179	=over 4
22	#$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		180
		181	=item --background-expr perl-expression
		182
		183	Specifies the Perl expression to evaluate.
		184
		185	=item --background-border
		186
		187	By default, the expression creates an image that fills the full window,
		188	overwriting borders and any other areas, such as the scrollbar.
		189
		190	Specifying this flag changes the behaviour, so that the image only
		191	replaces the background of the character area.
		192
		193	=back
		194
		195	=cut
		196
		197	our $HOME;
34	our ($self, $old, $new);	198	our ($self, $old, $new);
35	our ($x, $y, $w, $h);	199	our ($x, $y, $w, $h);
36		200
37	# enforce at least this interval between updates	201	# enforce at least this interval between updates
38	our $MIN_INTERVAL = 1/100;	202	our $MIN_INTERVAL = 1/100;
…		…
83	=item solid $width, $height, $colour	247	=item solid $width, $height, $colour
84		248
85	Creates a new image and completely fills it with the given colour. The	249	Creates a new image and completely fills it with the given colour. The
86	image is set to tiling mode.	250	image is set to tiling mode.
87		251
88	If <$width> and C<$height> are omitted, it creates a 1x1 image, which is	252	If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
89	useful for solid backgrounds or for use in filtering effects.	253	useful for solid backgrounds or for use in filtering effects.
90		254
91	=cut	255	=cut
92		256
93	sub solid($$;$) {	257	sub solid($$;$) {
…		…
100		264
101	=back	265	=back
102		266
103	=head2 VARIABLES	267	=head2 VARIABLES
104		268
105	The following functions provide variable data such as the terminal	269	The following functions provide variable data such as the terminal window
		270	dimensions. They are not (Perl-) variables, they jsut return stuff that
106	window dimensions. Most of them make your expression sensitive to some	271	varies. Most of them make your expression sensitive to some events, for
107	events, for example using C<TW> (terminal width) means your expression is	272	example using C<TW> (terminal width) means your expression is evaluated
108	evaluated again when the terminal is resized.	273	again when the terminal is resized.
109		274
110	=over 4	275	=over 4
111		276
112	=item TX	277	=item TX
113		278
…		…
160		325
161	When this function is used the expression will be reevaluated again in	326	When this function is used the expression will be reevaluated again in
162	C<$seconds> seconds.	327	C<$seconds> seconds.
163		328
164	Example: load some image and rotate it according to the time of day (as if it were	329	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.	330	the hour pointer of a clock). Update this image every minute.
166		331
167	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"	332	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
168		333
169	=item counter $seconds	334	=item counter $seconds
170		335
…		…
209	Similar to tile, but reflects the image each time it uses a new copy, so	374	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	375	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	376	edges and so on (with normal tiling, left edges always touch right edges
212	and top always touch bottom edges).	377	and top always touch bottom edges).
213		378
214	Exmaple: load an image and mirror it over the background, avoiding sharp	379	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	380	edges at the image borders at the expense of mirroring the image itself
216		381
217	mirror load "mybg.png"	382	mirror load "mybg.png"
218		383
219	=item pad $img	384	=item pad $img
…		…
221	Takes an image and modifies it so that all pixels outside the image area	386	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	387	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	388	image over another image or the background colour while leaving all
224	background pixels outside the image unchanged.	389	background pixels outside the image unchanged.
225		390
226	Example: load an image and display it in the upper left corner. The rets	391	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	392	of the space is left "empty" (transparent or wahtever your compisotr does
228	in alpha mode, else background colour).	393	in alpha mode, else background colour).
229		394
230	pad load "mybg.png"	395	pad load "mybg.png"
231		396
…		…
347	sub resize($$$) {	512	sub resize($$$) {
348	my $img = pop;	513	my $img = pop;
349	$img->scale ($_[0], $_[1])	514	$img->scale ($_[0], $_[1])
350	}	515	}
351		516
		517	=item move $dx, $dy, $img
		518
		519	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
		520	the vertical.
		521
		522	Example: move the image right by 20 pixels and down by 30.
		523
		524	move 20, 30, ...
		525
		526	=item rootalign $img
		527
		528	Moves the image so that it appears glued to the screen as opposed to the
		529	window. This gives the illusion of a larger area behind the window. It is
		530	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
		531	top left of the screen.
		532
		533	Example: load a background image, put it in mirror mode and root align it.
		534
		535	rootalign mirror load "mybg.png"
		536
		537	Example: take the screen background and align it, giving the illusion of
		538	transparency as long as the window isn't in front of other windows.
		539
		540	rootalign root
		541
		542	=cut
		543
352	sub move($$;$) {	544	sub move($$;$) {
353	my $img = pop->clone;	545	my $img = pop->clone;
354	$img->move ($_[0], $_[1]);	546	$img->move ($_[0], $_[1]);
355	$img	547	$img
356	}	548	}
		549
		550	sub rootalign($) {
		551	move -TX, -TY, $_[0]
		552	}
		553
		554	=item contrast $factor, $img
		555
		556	=item contrast $r, $g, $b, $img
		557
		558	=item contrast $r, $g, $b, $a, $img
		559
		560	Adjusts the I<contrast> of an image.
		561
		562	#TODO#
		563
		564	=item brightness $factor, $img
		565
		566	=item brightness $r, $g, $b, $img
		567
		568	=item brightness $r, $g, $b, $a, $img
		569
		570	Adjusts the brightness of an image.
		571
		572	=cut
		573
		574	sub contrast($$;$$;$) {
		575	my $img = pop;
		576	my ($r, $g, $b, $a) = @_;
		577
		578	($g, $b) = ($r, $r) if @_ < 4;
		579	$a = 1 if @_ < 5;
		580
		581	$img = $img->clone;
		582	$img->contrast ($r, $g, $b, $a);
		583	$img
		584	}
		585
		586	sub brightness($$;$$;$) {
		587	my $img = pop;
		588	my ($r, $g, $b, $a) = @_;
		589
		590	($g, $b) = ($r, $r) if @_ < 4;
		591	$a = 1 if @_ < 5;
		592
		593	$img = $img->clone;
		594	$img->brightness ($r, $g, $b, $a);
		595	$img
		596	}
		597
		598	=item blur $radius, $img
		599
		600	=item blur $radius_horz, $radius_vert, $img
		601
		602	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
		603	can also be specified separately.
		604
		605	Blurring is often I<very> slow, at least compared or other
		606	operators. Larger blur radii are slower than smaller ones, too, so if you
		607	don't want to freeze your screen for long times, start experimenting with
		608	low values for radius (<5).
		609
		610	=cut
		611
		612	sub blur($$;$) {
		613	my $img = pop;
		614	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
		615	}
		616
		617	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
		618
		619	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
		620	pointer at C<$center_x> and C<$center_y> (specified as percentage of image
		621	width/height), generating a new image with width C<$new_width> and height
		622	C<$new_height>.
		623
		624	#TODO# new width, height, maybe more operators?
		625
		626	Example: rotate the image by 90 degrees
		627
		628	=cut
357		629
358	sub rotate($$$$$$) {	630	sub rotate($$$$$$) {
359	my $img = pop;	631	my $img = pop;
360	$img->rotate (	632	$img->rotate (
361	$_[0],	633	$_[0],
…		…
364	$_[3] * $img->h * .01,	636	$_[3] * $img->h * .01,
365	$_[4] * (3.14159265 / 180),	637	$_[4] * (3.14159265 / 180),
366	)	638	)
367	}	639	}
368		640
369	sub blur($$;$) {
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	}
397
398	=back	641	=back
399		642
400	=cut	643	=cut
401		644
402	}	645	}
…		…
432		675
433	# set environment to evaluate user expression	676	# set environment to evaluate user expression
434		677
435	local $self = $arg_self;	678	local $self = $arg_self;
436		679
		680	local $HOME = $ENV{HOME};
437	local $old = $self->{state};	681	local $old = $self->{state};
438	local $new = my $state = $self->{state} = {};	682	local $new = my $state = $self->{state} = {};
439		683
440	($x, $y, $w, $h) =	684	($x, $y, $w, $h) =
441	$self->background_geometry ($self->{border});	685	$self->background_geometry ($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 1.41 by root, Fri Jun 8 22:21:48 2012 UTC

Diff Legend

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.35 by root, Fri Jun 8 08:06:38 2012 UTC vs.
Revision 1.41 by root, Fri Jun 8 22:21:48 2012 UTC