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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.63 by root, Tue Jun 19 18:17:56 2012 UTC vs.
Revision 1.68 by root, Sun Jul 1 21:47:07 2012 UTC

…		…
26	to be as simple as possible.	26	to be as simple as possible.
27		27
28	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
29	use:	29	use:
30		30
31	urxvt --background-expr 'scale load "/path/to/mybg.png"'	31	urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
32		32
33	Or specified as a X resource:	33	Or specified as a X resource:
34		34
35	URxvt.background-expr: scale load "/path/to/mybg.png"	35	URxvt.background-expr: scale keep { load "/path/to/mybg.png" }
36		36
37	=head1 THEORY OF OPERATION	37	=head1 THEORY OF OPERATION
38		38
39	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
40	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
…		…
53	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
54	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
55	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
56	timer elapses), then the expression will be evaluated again.	56	timer elapses), then the expression will be evaluated again.
57		57
58	For example, an expression such as C<scale load "$HOME/mybg.png"> scales the	58	For example, an expression such as C<scale keep { load "$HOME/mybg.png"
59	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
60	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
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 its 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:
68		68
		69	scale keep {
69	again 3600;	70	again 3600;
70	if (localtime now)[6]) {	71	if (localtime now)[6]) {
71	return scale load "$HOME/weekday.png";	72	return load "$HOME/weekday.png";
72	} else {	73	} else {
73	return scale load "$HOME/sunday.png";	74	return load "$HOME/sunday.png";
		75	}
74	}	76	}
75		77
76	This expression is evaluated once per hour. It will set F<sunday.png> as	78	This inner expression is evaluated once per hour (and whenever the
		79	temrinal window is resized). It sets F<sunday.png> as background on
77	background on Sundays, and F<weekday.png> on all other days.	80	Sundays, and F<weekday.png> on all other days.
78		81
79	Fortunately, we expect that most expressions will be much simpler, with	82	Fortunately, we expect that most expressions will be much simpler, with
80	little Perl knowledge needed.	83	little Perl knowledge needed.
81		84
82	Basically, you always start with a function that "generates" an image	85	Basically, you always start with a function that "generates" an image
…		…
115	horizontal and vertical dimensions. For example, this halves the image	118	horizontal and vertical dimensions. For example, this halves the image
116	width and doubles the image height:	119	width and doubles the image height:
117		120
118	scale 0.5, 2, load "$HOME/mypic.png"	121	scale 0.5, 2, load "$HOME/mypic.png"
119		122
120	Other effects than scaling are also readily available, for example, you can	123	IF you try out these expressions, you might suffer from some sluggishness,
121	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 agin
		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:
122		127
		128	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		129
		130	The C<keep> operator executes all the statements inside the braces only
		131	once, or when it thinks the outcome might change. In other cases it
		132	returns the last value computed by the brace block.
		133
		134	This means that the C<load> is only executed once, which makes it much
		135	faster, but also means that more memory is being used, because the loaded
		136	image must be kept in memory at all times. In this expression, the
		137	trade-off is likely worth it.
		138
		139	But back to effects: Other effects than scaling are also readily
		140	available, for example, you can tile the image to fill the whole window,
		141	instead of resizing it:
		142
123	tile load "$HOME/mypic.png"	143	tile keep { load "$HOME/mypic.png" }
124		144
125	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator	145	In fact, images returned by C<load> are in C<tile> mode by default, so the
126	is kind of superfluous.	146	C<tile> operator is kind of superfluous.
127		147
128	Another common effect is to mirror the image, so that the same edges touch:	148	Another common effect is to mirror the image, so that the same edges
		149	touch:
129		150
130	mirror load "$HOME/mypic.png"	151	mirror keep { load "$HOME/mypic.png" }
131		152
132	This is also a typical background expression:	153	Another common background expression is:
133		154
134	rootalign root	155	rootalign root
135		156
136	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
137	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
138	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:
139	moved around.	160	the image seems to be static while the window is moved around.
140		161
141	=head2 CYCLES AND CACHING	162	=head2 CACHING AND SENSITIVITY
142		163
143	=head3 C<load> et al.	164	Since some operations (such as C<load> and C<blur>) can take a long time,
		165	caching results can be very important for a smooth operation. Caching can
		166	also be useful to reduce memory usage, though, for example, when an image
		167	is cached by C<load>, it could be shared by multiple terminal windows
		168	running inside urxvtd.
144		169
145	As has been mentioned before, the expression might be evaluated multiple	170	=head3 C<keep { ... }> caching
146	times. Each time the expression is reevaluated, a new cycle is said to
147	have begun. Many operators cache their results till the next cycle.
148		171
149	For example, the C<load> operator keeps a copy of the image. If it is	172	The most important way to cache expensive operations is to use C<keep {
150	asked to load the same image on the next cycle it will not load it again,
151	but return the cached copy.
152
153	This only works for one cycle though, so as long as you load the same
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
157	This allows you to either speed things up by keeping multiple images in
158	memory, or conserve memory by loading images more often.
159
160	For example, you can keep two images in memory and use a random one like
161	this:
162
163	my $img1 = load "img1.png";
164	my $img2 = load "img2.png";
165	(0.5 > rand) ? $img1 : $img2
166
167	Since both images are "loaded" every time the expression is evaluated,
168	they are always kept in memory. Contrast this version:
169
170	my $path1 = "img1.png";
171	my $path2 = "img2.png";
172	load ((0.5 > rand) ? $path1 : $path2)
173
174	Here, a path is selected randomly, and load is only called for one image,
175	so keeps only one image in memory. If, on the next evaluation, luck
176	decides to use the other path, then it will have to load that image again.
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<{}>	173	... }>. The C<keep> operator takes a block of multiple statements enclosed
182	and evaluates it only.. once, returning any images the last statement	174	by C<{}> and keeps the return value in memory.
183	returned. Further calls simply produce the values from the cache.
184		175
		176	An expression can be "sensitive" to various external events, such as
		177	scaling or moving the window, root background changes and timers. Simply
		178	using an expression (such as C<scale> without parameters) that depends on
		179	certain changing values (called "variables"), or using those variables
		180	directly, will make an expression sensitive to these events - for example,
		181	using C<scale> or C<TW> will make the expression sensitive to the terminal
		182	size, and thus to resizing events.
		183
		184	When such an event happens, C<keep> will automatically trigger a
		185	reevaluation of the whole expression with the new value of the expression.
		186
185	This is most useful for expensive operations, such as C<blur>:	187	C<keep> is most useful for expensive operations, such as C<blur>:
186		188
187	rootalign once { blur 20, root }	189	rootalign keep { blur 20, root }
188		190
189	This makes a blurred copy of the root background once, and on subsequent	191	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	192	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	193	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	194	blurred pixmap) with speed (blur only needs to be redone when root
193	changes).	195	changes).
		196
		197	=head3 C<load> caching
		198
		199	The C<load> operator itself does not keep images in memory, but as long as
		200	the image is still in memory, C<load> will use the in-memory image instead
		201	of loading it freshly from disk.
		202
		203	That means that this expression:
		204
		205	keep { load "$HOME/path..." }
		206
		207	Not only caches the image in memory, other terminal instances that try to
		208	C<load> it can reuse that in-memory copy.
194		209
195	=head1 REFERENCE	210	=head1 REFERENCE
196		211
197	=head2 COMMAND LINE SWITCHES	212	=head2 COMMAND LINE SWITCHES
198		213
…		…
252	=item load $path	267	=item load $path
253		268
254	Loads the image at the given C<$path>. The image is set to plane tiling	269	Loads the image at the given C<$path>. The image is set to plane tiling
255	mode.	270	mode.
256		271
257	Loaded images will be cached for one cycle, and shared between temrinals	272	If the image is already in memory (e.g. because another terminal instance
258	running in the same process (e.g. in C<urxvtd>).	273	uses it), then the in-memory copy us returned instead.
259		274
260	#=item load_uc $path	275	=item load_uc $path
261	#	276
262	#Load uncached - same as load, but does not cache the image. This function	277	Load uncached - same as load, but does not cache the image, which means it
263	#is most useufl if you want to optimise a background expression in some	278	is I<always> loaded from the filesystem again.
264	#way.
265		279
266	=cut	280	=cut
		281
		282	sub load_uc($) {
		283	$self->new_img_from_file ($path)
		284	}
267		285
268	sub load($) {	286	sub load($) {
269	my ($path) = @_;	287	my ($path) = @_;
270		288
271	$_IMG_CACHE{$path} \|\| do {	289	$_IMG_CACHE{$path} \|\| do {
272	my $img = $self->new_img_from_file ($path);	290	my $img = load_uc $path;
273	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);	291	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
274	$img	292	$img
275	}	293	}
276	}	294	}
277		295
…		…
323		341
324	=item merge $img ...	342	=item merge $img ...
325		343
326	Takes any number of images and merges them together, creating a single	344	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	345	image containing them all. The tiling mode of the first image is used as
328	the tiling mdoe of the resulting image.	346	the tiling mode of the resulting image.
329		347
330	This function is called automatically when an expression returns multiple	348	This function is called automatically when an expression returns multiple
331	images.	349	images.
332		350
333	=cut	351	=cut
…		…
468	Using these functions make your expression sensitive to window moves.	486	Using these functions make your expression sensitive to window moves.
469		487
470	These functions are mainly useful to align images to the root window.	488	These functions are mainly useful to align images to the root window.
471		489
472	Example: load an image and align it so it looks as if anchored to the	490	Example: load an image and align it so it looks as if anchored to the
473	background.	491	background (that's exactly what C<rootalign> does btw.):
474		492
475	move -TX, -TY, load "mybg.png"	493	move -TX, -TY, keep { load "mybg.png" }
476		494
477	=item TW	495	=item TW
478		496
479	Return the width (C<TW>) and height (C<TH>) of the terminal window (the	497	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	498	terminal window is the full window by default, and the character area only
…		…
486	the window size to conserve memory.	504	the window size to conserve memory.
487		505
488	Example: take the screen background, clip it to the window size, blur it a	506	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.	507	bit, align it to the window position and use it as background.
490		508
491	clip move -TX, -TY, once { blur 5, root }	509	clip move -TX, -TY, keep { blur 5, root }
492		510
493	=cut	511	=cut
494		512
495	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }	513	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
496	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }	514	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
…		…
510	C<$seconds> seconds.	528	C<$seconds> seconds.
511		529
512	Example: load some image and rotate it according to the time of day (as if it were	530	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.	531	the hour pointer of a clock). Update this image every minute.
514		532
		533	again 60;
515	again 60; rotate 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"	534	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
516		535
517	=item counter $seconds	536	=item counter $seconds
518		537
519	Like C<again>, but also returns an increasing counter value, starting at	538	Like C<again>, but also returns an increasing counter value, starting at
520	0, which might be useful for some simple animation effects.	539	0, which might be useful for some simple animation effects.
…		…
557	assumed.	576	assumed.
558		577
559	Example: load an image, blur it, and clip it to the window size to save	578	Example: load an image, blur it, and clip it to the window size to save
560	memory.	579	memory.
561		580
562	clip blur 10, load "mybg.png"	581	clip keep { blur 10, load "mybg.png" }
563		582
564	=cut	583	=cut
565		584
566	sub clip($;$$;$$) {	585	sub clip($;$$;$$) {
567	my $img = pop;	586	my $img = pop;
…		…
661	the terminal window (or the box specified by C<$width> and C<$height> if	680	the terminal window (or the box specified by C<$width> and C<$height> if
662	given).	681	given).
663		682
664	Example: load an image and center it.	683	Example: load an image and center it.
665		684
666	center pad load "mybg.png"	685	center keep { pad load "mybg.png" }
667		686
668	=item rootalign $img	687	=item rootalign $img
669		688
670	Moves the image so that it appears glued to the screen as opposed to the	689	Moves the image so that it appears glued to the screen as opposed to the
671	window. This gives the illusion of a larger area behind the window. It is	690	window. This gives the illusion of a larger area behind the window. It is
672	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	691	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
673	top left of the screen.	692	top left of the screen.
674		693
675	Example: load a background image, put it in mirror mode and root align it.	694	Example: load a background image, put it in mirror mode and root align it.
676		695
677	rootalign mirror load "mybg.png"	696	rootalign keep { mirror load "mybg.png" }
678		697
679	Example: take the screen background and align it, giving the illusion of	698	Example: take the screen background and align it, giving the illusion of
680	transparency as long as the window isn't in front of other windows.	699	transparency as long as the window isn't in front of other windows.
681		700
682	rootalign root	701	rootalign root
…		…
707		726
708	sub rootalign($) {	727	sub rootalign($) {
709	move -TX, -TY, $_[0]	728	move -TX, -TY, $_[0]
710	}	729	}
711		730
712	=item rotate $center_x, $center_y, $degrees	731	=item rotate $center_x, $center_y, $degrees, $img
713		732
714	Rotates the image by C<$degrees> degrees, counter-clockwise, around the	733	Rotates the image clockwise by C<$degrees> degrees, around the point at
715	pointer at C<$center_x> and C<$center_y> (specified as factor of image	734	C<$center_x> and C<$center_y> (specified as factor of image width/height).
716	width/height).
717		735
718	#TODO# new width, height, maybe more operators?
719
720	Example: rotate the image by 90 degrees	736	Example: rotate the image by 90 degrees around it's center.
		737
		738	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
721		739
722	=cut	740	=cut
723		741
724	sub rotate($$$$) {	742	sub rotate($$$$) {
725	my $img = pop;	743	my $img = pop;
…		…
828	Anything that didn't fit any of the other categories, even after applying	846	Anything that didn't fit any of the other categories, even after applying
829	force and closing our eyes.	847	force and closing our eyes.
830		848
831	=over 4	849	=over 4
832		850
833	=item once { ... }	851	=item keep { ... }
834		852
835	This function takes a code block as argument, that is, one or more	853	This operator takes a code block as argument, that is, one or more
836	statements enclosed by braces.	854	statements enclosed by braces.
837		855
838	The trick is that this code block is only evaluated once - future calls	856	The trick is that this code block is only evaluated when the outcome
839	will simply return the original image (yes, it should only be used with	857	changes - on other calls the C<keep> simply returns the image it computed
840	images).	858	previously (yes, it should only be used with images). Or in other words,
		859	C<keep> I<caches> the result of the code block so it doesn't need to be
		860	computed again.
841		861
842	This can be extremely useful to avoid redoing the same slow operations	862	This can be extremely useful to avoid redoing slow operations - for
843	again and again- for example, if your background expression takes the root	863	example, if your background expression takes the root background, blurs it
844	background, blurs it and then root-aligns it it would have to blur the	864	and then root-aligns it it would have to blur the root background on every
845	root background on every window move or resize.	865	window move or resize.
		866
		867	Another example is C<load>, which can be quite slow.
846		868
847	In fact, urxvt itself encloses the whole expression in some kind of	869	In fact, urxvt itself encloses the whole expression in some kind of
848	C<once> block so it only is reevaluated as required.	870	C<keep> block so it only is reevaluated as required.
849		871
850	Putting the blur into a C<once> block will make sure the blur is only done	872	Putting the blur into a C<keep> block will make sure the blur is only done
851	once:	873	once, while the C<rootalign> is still done each time the window moves.
852		874
853	rootlign once { blur 10, root }	875	rootlign keep { blur 10, root }
854		876
855	This leaves the question of how to force reevaluation of the block,	877	This leaves the question of how to force reevaluation of the block,
856	in case the root background changes: If expression inside the block	878	in case the root background changes: If expression inside the block
857	is sensitive to some event (root background changes, window geometry	879	is sensitive to some event (root background changes, window geometry
858	changes), then it will be reevaluated automatically as needed.	880	changes), then it will be reevaluated automatically as needed.
859		881
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	882	=cut
866		883
867	sub once(&) {	884	sub keep(&) {
868	my $id = $_[0]+0;	885	my $id = $_[0]+0;
869		886
870	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];	887	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
871		888
872	unless ($frame->[FR_CACHE]) {	889	unless ($frame->[FR_CACHE]) {
…		…
879	# clear this frame cache, also for all parents	896	# clear this frame cache, also for all parents
880	for (my $frame = $frame; $frame; $frame = $frame->[0]) {	897	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
881	undef $frame->[FR_CACHE];	898	undef $frame->[FR_CACHE];
882	}	899	}
883		900
884	unless ($self->{term}) {
885	use Data::Dump;
886	ddx $frame;
887	exit;
888	}
889
890	$self->recalculate;	901	$self->recalculate;
891	});	902	});
892	};	903	};
893		904
894	# in scalar context we always return the first original result, which	905	# in scalar context we always return the first original result, which
…		…
896	wantarray	907	wantarray
897	? @{ $frame->[FR_CACHE] }	908	? @{ $frame->[FR_CACHE] }
898	: $frame->[FR_CACHE][0]	909	: $frame->[FR_CACHE][0]
899	}	910	}
900		911
901	sub once_again() {	912	# sub keep_clear() {
902	delete $self->{frame_cache};	913	# delete $self->{frame_cache};
903	}	914	# }
904		915
905	=back	916	=back
906		917
907	=cut	918	=cut
908		919

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.63 by root, Tue Jun 19 18:17:56 2012 UTC vs. Revision 1.68 by root, Sun Jul 1 21:47:07 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.63 by root, Tue Jun 19 18:17:56 2012 UTC vs.
Revision 1.68 by root, Sun Jul 1 21:47:07 2012 UTC