[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 1.70 by root, Mon Jul 2 01:35:37 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 $path
261	#	276
262	#Load uncached - same as load, but does not cache the image. This function	277	Load uncached - same as load, but does not cache the image, which means it
263	#is most useufl if you want to optimise a background expression in some	278	is I<always> loaded from the filesystem again.
264	#way.
265		279
266	=cut	280	=cut
267		281
268	sub load($) {	282	sub load($) {
269	my ($path) = @_;	283	my ($path) = @_;
…		…
323		337
324	=item merge $img ...	338	=item merge $img ...
325		339
326	Takes any number of images and merges them together, creating a single	340	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	341	image containing them all. The tiling mode of the first image is used as
328	the tiling mdoe of the resulting image.	342	the tiling mode of the resulting image.
329		343
330	This function is called automatically when an expression returns multiple	344	This function is called automatically when an expression returns multiple
331	images.	345	images.
332		346
333	=cut	347	=cut
…		…
468	Using these functions make your expression sensitive to window moves.	482	Using these functions make your expression sensitive to window moves.
469		483
470	These functions are mainly useful to align images to the root window.	484	These functions are mainly useful to align images to the root window.
471		485
472	Example: load an image and align it so it looks as if anchored to the	486	Example: load an image and align it so it looks as if anchored to the
473	background.	487	background (that's exactly what C<rootalign> does btw.):
474		488
475	move -TX, -TY, load "mybg.png"	489	move -TX, -TY, keep { load "mybg.png" }
476		490
477	=item TW	491	=item TW
478		492
479	Return the width (C<TW>) and height (C<TH>) of the terminal window (the	493	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	494	terminal window is the full window by default, and the character area only
…		…
486	the window size to conserve memory.	500	the window size to conserve memory.
487		501
488	Example: take the screen background, clip it to the window size, blur it a	502	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.	503	bit, align it to the window position and use it as background.
490		504
491	clip move -TX, -TY, once { blur 5, root }	505	clip move -TX, -TY, keep { blur 5, root }
492		506
493	=cut	507	=cut
494		508
495	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }	509	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
496	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }	510	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
…		…
510	C<$seconds> seconds.	524	C<$seconds> seconds.
511		525
512	Example: load some image and rotate it according to the time of day (as if it were	526	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.	527	the hour pointer of a clock). Update this image every minute.
514		528
		529	again 60;
515	again 60; rotate 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"	530	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
516		531
517	=item counter $seconds	532	=item counter $seconds
518		533
519	Like C<again>, but also returns an increasing counter value, starting at	534	Like C<again>, but also returns an increasing counter value, starting at
520	0, which might be useful for some simple animation effects.	535	0, which might be useful for some simple animation effects.
…		…
557	assumed.	572	assumed.
558		573
559	Example: load an image, blur it, and clip it to the window size to save	574	Example: load an image, blur it, and clip it to the window size to save
560	memory.	575	memory.
561		576
562	clip blur 10, load "mybg.png"	577	clip keep { blur 10, load "mybg.png" }
563		578
564	=cut	579	=cut
565		580
566	sub clip($;$$;$$) {	581	sub clip($;$$;$$) {
567	my $img = pop;	582	my $img = pop;
…		…
661	the terminal window (or the box specified by C<$width> and C<$height> if	676	the terminal window (or the box specified by C<$width> and C<$height> if
662	given).	677	given).
663		678
664	Example: load an image and center it.	679	Example: load an image and center it.
665		680
666	center pad load "mybg.png"	681	center keep { pad load "mybg.png" }
667		682
668	=item rootalign $img	683	=item rootalign $img
669		684
670	Moves the image so that it appears glued to the screen as opposed to the	685	Moves the image so that it appears glued to the screen as opposed to the
671	window. This gives the illusion of a larger area behind the window. It is	686	window. This gives the illusion of a larger area behind the window. It is
672	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	687	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
673	top left of the screen.	688	top left of the screen.
674		689
675	Example: load a background image, put it in mirror mode and root align it.	690	Example: load a background image, put it in mirror mode and root align it.
676		691
677	rootalign mirror load "mybg.png"	692	rootalign keep { mirror load "mybg.png" }
678		693
679	Example: take the screen background and align it, giving the illusion of	694	Example: take the screen background and align it, giving the illusion of
680	transparency as long as the window isn't in front of other windows.	695	transparency as long as the window isn't in front of other windows.
681		696
682	rootalign root	697	rootalign root
…		…
707		722
708	sub rootalign($) {	723	sub rootalign($) {
709	move -TX, -TY, $_[0]	724	move -TX, -TY, $_[0]
710	}	725	}
711		726
712	=item rotate $center_x, $center_y, $degrees	727	=item rotate $center_x, $center_y, $degrees, $img
713		728
714	Rotates the image by C<$degrees> degrees, counter-clockwise, around the	729	Rotates the image clockwise by C<$degrees> degrees, around the point at
715	pointer at C<$center_x> and C<$center_y> (specified as factor of image	730	C<$center_x> and C<$center_y> (specified as factor of image width/height).
716	width/height).
717		731
718	#TODO# new width, height, maybe more operators?
719
720	Example: rotate the image by 90 degrees	732	Example: rotate the image by 90 degrees around it's center.
		733
		734	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
721		735
722	=cut	736	=cut
723		737
724	sub rotate($$$$) {	738	sub rotate($$$$) {
725	my $img = pop;	739	my $img = pop;
…		…
736		750
737	The following operators change the pixels of the image.	751	The following operators change the pixels of the image.
738		752
739	=over 4	753	=over 4
740		754
		755	=item tint $color, $img
		756
		757	Tints the image in the given colour.
		758
		759	Example: tint the image red.
		760
		761	tint "red", load "rgb.png"
		762
		763	Example: the same, but specify the colour by component.
		764
		765	tint [1, 0, 0], load "rgb.png"
		766
		767	=cut
		768
		769	sub tint($$) {
		770	$_[1]->tint ($_[0])
		771	}
		772
741	=item contrast $factor, $img	773	=item contrast $factor, $img
742		774
743	=item contrast $r, $g, $b, $img	775	=item contrast $r, $g, $b, $img
744		776
745	=item contrast $r, $g, $b, $a, $img	777	=item contrast $r, $g, $b, $a, $img
…		…
828	Anything that didn't fit any of the other categories, even after applying	860	Anything that didn't fit any of the other categories, even after applying
829	force and closing our eyes.	861	force and closing our eyes.
830		862
831	=over 4	863	=over 4
832		864
833	=item once { ... }	865	=item keep { ... }
834		866
835	This function takes a code block as argument, that is, one or more	867	This operator takes a code block as argument, that is, one or more
836	statements enclosed by braces.	868	statements enclosed by braces.
837		869
838	The trick is that this code block is only evaluated once - future calls	870	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	871	changes - on other calls the C<keep> simply returns the image it computed
840	images).	872	previously (yes, it should only be used with images). Or in other words,
		873	C<keep> I<caches> the result of the code block so it doesn't need to be
		874	computed again.
841		875
842	This can be extremely useful to avoid redoing the same slow operations	876	This can be extremely useful to avoid redoing slow operations - for
843	again and again- for example, if your background expression takes the root	877	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	878	and then root-aligns it it would have to blur the root background on every
845	root background on every window move or resize.	879	window move or resize.
		880
		881	Another example is C<load>, which can be quite slow.
846		882
847	In fact, urxvt itself encloses the whole expression in some kind of	883	In fact, urxvt itself encloses the whole expression in some kind of
848	C<once> block so it only is reevaluated as required.	884	C<keep> block so it only is reevaluated as required.
849		885
850	Putting the blur into a C<once> block will make sure the blur is only done	886	Putting the blur into a C<keep> block will make sure the blur is only done
851	once:	887	once, while the C<rootalign> is still done each time the window moves.
852		888
853	rootlign once { blur 10, root }	889	rootlign keep { blur 10, root }
854		890
855	This leaves the question of how to force reevaluation of the block,	891	This leaves the question of how to force reevaluation of the block,
856	in case the root background changes: If expression inside the block	892	in case the root background changes: If expression inside the block
857	is sensitive to some event (root background changes, window geometry	893	is sensitive to some event (root background changes, window geometry
858	changes), then it will be reevaluated automatically as needed.	894	changes), then it will be reevaluated automatically as needed.
859		895
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	896	=cut
866		897
867	sub once(&) {	898	sub keep(&) {
868	my $id = $_[0]+0;	899	my $id = $_[0]+0;
869		900
870	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];	901	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
871		902
872	unless ($frame->[FR_CACHE]) {	903	unless ($frame->[FR_CACHE]) {
…		…
879	# clear this frame cache, also for all parents	910	# clear this frame cache, also for all parents
880	for (my $frame = $frame; $frame; $frame = $frame->[0]) {	911	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
881	undef $frame->[FR_CACHE];	912	undef $frame->[FR_CACHE];
882	}	913	}
883		914
884	unless ($self->{term}) {
885	use Data::Dump;
886	ddx $frame;
887	exit;
888	}
889
890	$self->recalculate;	915	$self->recalculate;
891	});	916	});
892	};	917	};
893		918
894	# in scalar context we always return the first original result, which	919	# in scalar context we always return the first original result, which
…		…
896	wantarray	921	wantarray
897	? @{ $frame->[FR_CACHE] }	922	? @{ $frame->[FR_CACHE] }
898	: $frame->[FR_CACHE][0]	923	: $frame->[FR_CACHE][0]
899	}	924	}
900		925
901	sub once_again() {	926	# sub keep_clear() {
902	delete $self->{frame_cache};	927	# delete $self->{frame_cache};
903	}	928	# }
904		929
905	=back	930	=back
906		931
907	=cut	932	=cut
908		933

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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 1.70 by root, Mon Jul 2 01:35:37 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 1.70 by root, Mon Jul 2 01:35:37 2012 UTC