[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 1.36 by root, Fri Jun 8 20:23:09 2012 UTC

…		…
7		7
8	=head1 background - manage terminal background	8	=head1 background - manage terminal background
9		9
10	=head2 SYNOPSIS	10	=head2 SYNOPSIS
11		11
12	rxvt -background-expr 'background expression'	12	urxvt --background-expr 'background expression'
13	-background-border	13	--background-border
14		14
15	=head2 DESCRIPTION	15	=head2 DESCRIPTION
16		16
		17	This extension manages the terminal background by creating a picture that
		18	is behind the text, replacing the normal background colour.
		19
		20	It does so by evaluating a Perl expression that I<calculates> the image on
		21	the fly, for example, by grabbing the root background or loading a file.
		22
		23	While the full power of Perl is available, the operators have been design
		24	to be as simple as possible.
		25
		26	For example, to load an image and scale it to the window size, you would
		27	use:
		28
		29	urxvt --background-expr 'scale load "/path/to/mybg.png"'
		30
		31	Or specified as a X resource:
		32
		33	URxvt.background-expr: scale load "/path/to/mybg.png"
		34
		35	=head2 THEORY OF OPERATION
		36
		37	At startup, just before the window is mapped for the first time, the
		38	expression is evaluated and must yield an image. The image is then
		39	extended as necessary to cover the whole terminal window, and is set as a
		40	background pixmap.
		41
		42	If the image contains an alpha channel, then it will be used as-is in
		43	visuals that support alpha channels (for example, for a compositing
		44	manager). In other visuals, the terminal background colour will be used to
		45	replace any transparency.
		46
		47	When the expression relies, directly or indirectly, on the window size,
		48	position, the root pixmap, or a timer, then it will be remembered. If not,
		49	then it will be removed.
		50
		51	If any of the parameters that the expression relies on changes (when the
		52	window is moved or resized, its position or size changes; when the root
		53	pixmap is replaced by another one the root background changes; or when the
		54	timer elapses), then the expression will be evaluated again.
		55
		56	For example, an expression such as C<scale load "$HOME/mybg.png"> scales the
		57	image to the window size, so it relies on the window size and will
		58	be reevaluated each time it is changed, but not when it moves for
		59	example. That ensures that the picture always fills the terminal, even
		60	after it's size changes.
		61
		62	=head3 EXPRESSIONS
		63
		64	Expressions are normal Perl expressions, in fact, they are Perl blocks -
		65	which means you could use multiple lines and statements:
		66
		67	again 3600;
		68	if (localtime now)[6]) {
		69	return scale load "$HOME/weekday.png";
		70	} else {
		71	return scale load "$HOME/sunday.png";
		72	}
		73
		74	This expression gets evaluated once per hour. It will set F<sunday.png> as
		75	background on sundays, and F<weekday.png> on all other days.
		76
		77	Fortunately, we expect that most expressions will be much simpler, with
		78	little Perl knowledge needed.
		79
		80	Basically, you always start with a function that "generates" an image
		81	object, such as C<load>, which loads an image from disk, or C<root>, which
		82	returns the root window background image:
		83
		84	load "$HOME/mypic.png"
		85
		86	The path is usually specified as a quoted string (the exact rules can be
		87	found in the L<perlop> manpage). The F<$HOME> at the beginning of the
		88	string is expanded to the home directory.
		89
		90	Then you prepend one or more modifiers or filtering expressions, such as
		91	C<scale>:
		92
		93	scale load "$HOME/mypic.png"
		94
		95	Just like a mathematical expression with functions, you should read these
		96	expressions from right to left, as the C<load> is evaluated first, and
		97	its result becomes the argument to the C<scale> function.
		98
		99	Many operators also allow some parameters preceding the input image
		100	that modify its behaviour. For example, C<scale> without any additional
		101	arguments scales the image to size of the terminal window. If you specify
		102	an additional argument, it uses it as a percentage:
		103
		104	scale 200, load "$HOME/mypic.png"
		105
		106	This enlarges the image by a factor of 2 (200%). As you can see, C<scale>
		107	has now two arguments, the C<200> and the C<load> expression, while
		108	C<load> only has one argument. Arguments are separated from each other by
		109	commas.
		110
		111	Scale also accepts two arguments, which are then separate factors for both
		112	horizontal and vertical dimensions. For example, this halves the image
		113	width and doubles the image height:
		114
		115	scale 50, 200, load "$HOME/mypic.png"
		116
		117	TODO
		118
		119	=head3 CYCLES AND CACHING
		120
		121	TODO
		122
		123	Each time the expression is reevaluated, a new cycle is said to have begun. Many operators
		124	cache their results till the next cycle. For example
		125
17	=head2 REFERENCE	126	=head2 REFERENCE
18		127
19	=cut	128	=head3 COMMAND LINE SWITCHES
20		129
		130	=over 4
		131
		132	=item --background-expr perl-expression
		133
		134	Specifies the Perl expression to evaluate.
		135
		136	=item --background-border
		137
		138	By default, the expression creates an image that fills the full window,
		139	overwriting borders and any other areas, such as the scrollbar.
		140
		141	Specifying this flag changes the behaviour, so that the image only
		142	replaces the background of the character area.
		143
		144	=back
		145
		146	=cut
		147
21	our $EXPR;	148	our $EXPR;#d#
22	#$EXPR = 'move W * 0.1, -H * 0.1, resize W * 0.5, H * 0.5, repeat_none load "opensource.png"';	149	#$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"';	150	$EXPR = 'move -TX, -TY, load "argb.png"';
24	#$EXPR = '	151	#$EXPR = '
25	# rotate W, H, 50, 50, counter 1/59.95, repeat_mirror,	152	# rotate W, H, 50, 50, counter 1/59.95, repeat_mirror,
26	# clip X, Y, W, H, repeat_mirror,	153	# clip X, Y, W, H, repeat_mirror,
…		…
29	#$EXPR = 'solid "red"';	156	#$EXPR = 'solid "red"';
30	#$EXPR = 'blur root, 10, 10'	157	#$EXPR = 'blur root, 10, 10'
31	#$EXPR = 'blur move (root, -x, -y), 5, 5'	158	#$EXPR = 'blur move (root, -x, -y), 5, 5'
32	#resize load "/root/pix/das_fette_schwein.jpg", w, h	159	#resize load "/root/pix/das_fette_schwein.jpg", w, h
33		160
		161	our $HOME;
34	our ($self, $old, $new);	162	our ($self, $old, $new);
35	our ($x, $y, $w, $h);	163	our ($x, $y, $w, $h);
36		164
37	# enforce at least this interval between updates	165	# enforce at least this interval between updates
38	our $MIN_INTERVAL = 1/100;	166	our $MIN_INTERVAL = 1/100;
…		…
160		288
161	When this function is used the expression will be reevaluated again in	289	When this function is used the expression will be reevaluated again in
162	C<$seconds> seconds.	290	C<$seconds> seconds.
163		291
164	Example: load some image and rotate it according to the time of day (as if it were	292	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.	293	the hour pointer of a clock). Update this image every minute.
166		294
167	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"	295	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
168		296
169	=item counter $seconds	297	=item counter $seconds
170		298
…		…
209	Similar to tile, but reflects the image each time it uses a new copy, so	337	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	338	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	339	edges and so on (with normal tiling, left edges always touch right edges
212	and top always touch bottom edges).	340	and top always touch bottom edges).
213		341
214	Exmaple: load an image and mirror it over the background, avoiding sharp	342	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	343	edges at the image borders at the expense of mirroring the image itself
216		344
217	mirror load "mybg.png"	345	mirror load "mybg.png"
218		346
219	=item pad $img	347	=item pad $img
…		…
221	Takes an image and modifies it so that all pixels outside the image area	349	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	350	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	351	image over another image or the background colour while leaving all
224	background pixels outside the image unchanged.	352	background pixels outside the image unchanged.
225		353
226	Example: load an image and display it in the upper left corner. The rets	354	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	355	of the space is left "empty" (transparent or wahtever your compisotr does
228	in alpha mode, else background colour).	356	in alpha mode, else background colour).
229		357
230	pad load "mybg.png"	358	pad load "mybg.png"
231		359
…		…
347	sub resize($$$) {	475	sub resize($$$) {
348	my $img = pop;	476	my $img = pop;
349	$img->scale ($_[0], $_[1])	477	$img->scale ($_[0], $_[1])
350	}	478	}
351		479
		480	=item move $dx, $dy, $img
		481
		482	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
		483	the vertical.
		484
		485	Example: move the image right by 20 pixels and down by 30.
		486
		487	move 20, 30, ...
		488
		489	=item rootalign $img
		490
		491	Moves the image so that it appears glued to the screen as opposed to the
		492	window. This gives the illusion of a larger area behind the window. It is
		493	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
		494	top left of the screen.
		495
		496	Example: load a background image, put it in mirror mode and root align it.
		497
		498	rootalign mirror load "mybg.png"
		499
		500	Example: take the screen background and align it, giving the illusion of
		501	transparency as long as the window isn't in front of other windows.
		502
		503	rootalign root
		504
		505	=cut
		506
352	sub move($$;$) {	507	sub move($$;$) {
353	my $img = pop->clone;	508	my $img = pop->clone;
354	$img->move ($_[0], $_[1]);	509	$img->move ($_[0], $_[1]);
355	$img	510	$img
		511	}
		512
		513	sub rootalign($) {
		514	move -TX, -TY, $_[0]
		515	}
		516
		517	=item contrast $factor, $img
		518
		519	=item contrast $r, $g, $b, $img
		520
		521	=item contrast $r, $g, $b, $a, $img
		522
		523	Adjusts the I<contrast> of an image.
		524
		525	=item brightness $factor, $img
		526
		527	=item brightness $r, $g, $b, $img
		528
		529	=item brightness $r, $g, $b, $a, $img
		530
		531	=cut
		532
		533	sub contrast($$;$$;$) {
		534	my $img = pop;
		535	my ($r, $g, $b, $a) = @_;
		536
		537	($g, $b) = ($r, $r) if @_ < 4;
		538	$a = 1 if @_ < 5;
		539
		540	$img = $img->clone;
		541	# $img->contrast ($r, $g, $b, $a);
		542	$img
		543	}
		544
		545	sub brightness($$;$$;$) {
		546	my $img = pop;
		547	my ($r, $g, $b, $a) = @_;
		548
		549	($g, $b) = ($r, $r) if @_ < 4;
		550	$a = 1 if @_ < 5;
		551
		552	$img = $img->clone;
		553	$img->brightness ($r, $g, $b, $a);
		554	$img
		555	}
		556
		557	sub blur($$;$) {
		558	my $img = pop;
		559	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
356	}	560	}
357		561
358	sub rotate($$$$$$) {	562	sub rotate($$$$$$) {
359	my $img = pop;	563	my $img = pop;
360	$img->rotate (	564	$img->rotate (
…		…
364	$_[3] * $img->h * .01,	568	$_[3] * $img->h * .01,
365	$_[4] * (3.14159265 / 180),	569	$_[4] * (3.14159265 / 180),
366	)	570	)
367	}	571	}
368		572
369	sub blur($$;$) {
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	573	=back
399		574
400	=cut	575	=cut
401		576
402	}	577	}
…		…
432		607
433	# set environment to evaluate user expression	608	# set environment to evaluate user expression
434		609
435	local $self = $arg_self;	610	local $self = $arg_self;
436		611
		612	local $HOME = $ENV{HOME};
437	local $old = $self->{state};	613	local $old = $self->{state};
438	local $new = my $state = $self->{state} = {};	614	local $new = my $state = $self->{state} = {};
439		615
440	($x, $y, $w, $h) =	616	($x, $y, $w, $h) =
441	$self->background_geometry ($self->{border});	617	$self->background_geometry ($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 1.36 by root, Fri Jun 8 20:23:09 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 1.36 by root, Fri Jun 8 20:23:09 2012 UTC