[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 1.64 by root, Tue Jun 19 20:49:53 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 expression is evaluated once per hour. It will set F<sunday.png> as
77	background on Sundays, and F<weekday.png> on all other days.	79	background on Sundays, and F<weekday.png> on all other days.
78		80
…		…
115	horizontal and vertical dimensions. For example, this halves the image	117	horizontal and vertical dimensions. For example, this halves the image
116	width and doubles the image height:	118	width and doubles the image height:
117		119
118	scale 0.5, 2, load "$HOME/mypic.png"	120	scale 0.5, 2, load "$HOME/mypic.png"
119		121
120	Other effects than scaling are also readily available, for example, you can	122	IF you try out these expressions, you might suffer from sluggishness,
121	tile the image to fill the whole window, instead of resizing it:	123	because each time the terminal is resized, it again loads the PNG image
		124	and scales it. Scaling is usually fats, but loading the image can be quite
		125	time consuming. This is where C<keep> comes in handy:
122		126
		127	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		128
		129	The C<keep> operator executes all the statements inside the braces only
		130	once, or when it thinks the outcome might change. In other cases it
		131	returns the last value computed by the brace block.
		132
		133	This means that the C<load> is only executed once, which makes it much
		134	faster, but alos means that more memory is being used, because the loaded
		135	image must be kept in memory at all times. In this expression, the
		136	trade-off is likely worth it.
		137
		138	But back to effects: Other effects than scaling are also readily
		139	available, for example, you can tile the image to fill the whole window,
		140	instead of resizing it:
		141
123	tile load "$HOME/mypic.png"	142	tile keep { load "$HOME/mypic.png" }
124		143
125	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator	144	In fact, images returned by C<load> are in C<tile> mode by default, so the
126	is kind of superfluous.	145	C<tile> operator is kind of superfluous.
127		146
128	Another common effect is to mirror the image, so that the same edges touch:	147	Another common effect is to mirror the image, so that the same edges
		148	touch:
129		149
130	mirror load "$HOME/mypic.png"	150	mirror keep { load "$HOME/mypic.png" }
131		151
132	This is also a typical background expression:	152	Another common background expression is:
133		153
134	rootalign root	154	rootalign root
135		155
136	It first takes a snapshot of the screen background image, and then	156	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	157	moves it to the upper left corner of the screen (as opposed to the upepr
138	pseudo-transparency, as the image seems to be static while the window is	158	left corner of the terminal window)- the result is pseudo-transparency:
139	moved around.	159	the image seems to be static while the window is moved around.
140		160
141	=head2 CYCLES AND CACHING	161	=head2 CACHING AND SENSITIVITY
142		162
143	=head3 C<load> et al.	163	Since some operations (such as C<load> and C<blur>) can take a long time,
		164	caching results can be very important for a smooth operation. Caching can
		165	also be useful to reduce memory usage, though, for example, when an image
		166	is cached by C<load>, it could be shared by multiple terminal windows
		167	running inside urxvtd.
144		168
145	As has been mentioned before, the expression might be evaluated multiple	169	=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		170
149	For example, the C<load> operator keeps a copy of the image. If it is	171	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<{}>	172	... }>. The C<keep> operator takes a block of multiple statements enclosed
182	and evaluates it only.. once, returning any images the last statement	173	by C<{}> and keeps the return value in memory.
183	returned. Further calls simply produce the values from the cache.
184		174
		175	An expression can be "sensitive" to various external events, such as
		176	scaling or moving the window, root backgorund changes and timers. Simply
		177	using an expression (such as C<scale> without parameters) that depend on
		178	certain changing values (called "variables"), or using those variables
		179	directly, will make an expression sensitive to these events - for example,
		180	using C<scale> or C<TW> will make the expression sensitive to the terminal
		181	size, and thus to resizing events.
		182
		183	When such an event happens, C<keep> will automatically trigger a
		184	reevaluation of the whole expression with the new value of the expression.
		185
185	This is most useful for expensive operations, such as C<blur>:	186	C<keep> is most useful for expensive operations, such as C<blur>:
186		187
187	rootalign once { blur 20, root }	188	rootalign once { blur 20, root }
188		189
189	This makes a blurred copy of the root background once, and on subsequent	190	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	191	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	192	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	193	blurred pixmap) with speed (blur only needs to be redone when root
193	changes).	194	changes).
		195
		196	=head3 C<load> caching
		197
		198	The C<load> operator itself does not keep images in memory, but as long as
		199	the image is still in memory, C<load> will use the in-memory image instead
		200	of loading it freshly from disk.
		201
		202	That means that this expression:
		203
		204	keep { load "$HOME/path..." }
		205
		206	Not only caches the image in memory, other terminal instances that try to
		207	C<load> it can reuse that in-memory copy.
194		208
195	=head1 REFERENCE	209	=head1 REFERENCE
196		210
197	=head2 COMMAND LINE SWITCHES	211	=head2 COMMAND LINE SWITCHES
198		212
…		…
252	=item load $path	266	=item load $path
253		267
254	Loads the image at the given C<$path>. The image is set to plane tiling	268	Loads the image at the given C<$path>. The image is set to plane tiling
255	mode.	269	mode.
256		270
257	Loaded images will be cached for one cycle, and shared between temrinals	271	If the image is already in memory (e.g. because another temrinal instance
258	running in the same process (e.g. in C<urxvtd>).	272	uses it), then the in-memory copy us returned instead.
259		273
260	#=item load_uc $path	274	=item load_uc $path
261	#	275
262	#Load uncached - same as load, but does not cache the image. This function	276	Load uncached - same as load, but does not cache the image, which means it
263	#is most useufl if you want to optimise a background expression in some	277	is I<always> loaded from the filesystem again.
264	#way.
265		278
266	=cut	279	=cut
		280
		281	sub load_uc($) {
		282	$self->new_img_from_file ($path)
		283	}
267		284
268	sub load($) {	285	sub load($) {
269	my ($path) = @_;	286	my ($path) = @_;
270		287
271	$_IMG_CACHE{$path} \|\| do {	288	$_IMG_CACHE{$path} \|\| do {
272	my $img = $self->new_img_from_file ($path);	289	my $img = load_uc $path;
273	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);	290	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
274	$img	291	$img
275	}	292	}
276	}	293	}
277		294
…		…
468	Using these functions make your expression sensitive to window moves.	485	Using these functions make your expression sensitive to window moves.
469		486
470	These functions are mainly useful to align images to the root window.	487	These functions are mainly useful to align images to the root window.
471		488
472	Example: load an image and align it so it looks as if anchored to the	489	Example: load an image and align it so it looks as if anchored to the
473	background.	490	background (that's exactly what C<rootalign> does btw.):
474		491
475	move -TX, -TY, load "mybg.png"	492	move -TX, -TY, keep { load "mybg.png" }
476		493
477	=item TW	494	=item TW
478		495
479	Return the width (C<TW>) and height (C<TH>) of the terminal window (the	496	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	497	terminal window is the full window by default, and the character area only
…		…
486	the window size to conserve memory.	503	the window size to conserve memory.
487		504
488	Example: take the screen background, clip it to the window size, blur it a	505	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.	506	bit, align it to the window position and use it as background.
490		507
491	clip move -TX, -TY, once { blur 5, root }	508	clip move -TX, -TY, keep { blur 5, root }
492		509
493	=cut	510	=cut
494		511
495	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }	512	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
496	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }	513	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
…		…
510	C<$seconds> seconds.	527	C<$seconds> seconds.
511		528
512	Example: load some image and rotate it according to the time of day (as if it were	529	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.	530	the hour pointer of a clock). Update this image every minute.
514		531
		532	again 60;
515	again 60; rotate 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"	533	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
516		534
517	=item counter $seconds	535	=item counter $seconds
518		536
519	Like C<again>, but also returns an increasing counter value, starting at	537	Like C<again>, but also returns an increasing counter value, starting at
520	0, which might be useful for some simple animation effects.	538	0, which might be useful for some simple animation effects.
…		…
557	assumed.	575	assumed.
558		576
559	Example: load an image, blur it, and clip it to the window size to save	577	Example: load an image, blur it, and clip it to the window size to save
560	memory.	578	memory.
561		579
562	clip blur 10, load "mybg.png"	580	clip keep { blur 10, load "mybg.png" }
563		581
564	=cut	582	=cut
565		583
566	sub clip($;$$;$$) {	584	sub clip($;$$;$$) {
567	my $img = pop;	585	my $img = pop;
…		…
661	the terminal window (or the box specified by C<$width> and C<$height> if	679	the terminal window (or the box specified by C<$width> and C<$height> if
662	given).	680	given).
663		681
664	Example: load an image and center it.	682	Example: load an image and center it.
665		683
666	center pad load "mybg.png"	684	center keep { pad load "mybg.png" }
667		685
668	=item rootalign $img	686	=item rootalign $img
669		687
670	Moves the image so that it appears glued to the screen as opposed to the	688	Moves the image so that it appears glued to the screen as opposed to the
671	window. This gives the illusion of a larger area behind the window. It is	689	window. This gives the illusion of a larger area behind the window. It is
672	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	690	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
673	top left of the screen.	691	top left of the screen.
674		692
675	Example: load a background image, put it in mirror mode and root align it.	693	Example: load a background image, put it in mirror mode and root align it.
676		694
677	rootalign mirror load "mybg.png"	695	rootalign keep { mirror load "mybg.png" }
678		696
679	Example: take the screen background and align it, giving the illusion of	697	Example: take the screen background and align it, giving the illusion of
680	transparency as long as the window isn't in front of other windows.	698	transparency as long as the window isn't in front of other windows.
681		699
682	rootalign root	700	rootalign root
…		…
707		725
708	sub rootalign($) {	726	sub rootalign($) {
709	move -TX, -TY, $_[0]	727	move -TX, -TY, $_[0]
710	}	728	}
711		729
712	=item rotate $center_x, $center_y, $degrees	730	=item rotate $center_x, $center_y, $degrees, $img
713		731
714	Rotates the image by C<$degrees> degrees, counter-clockwise, around the	732	Rotates the image clockwise by C<$degrees> degrees, around the point at
715	pointer at C<$center_x> and C<$center_y> (specified as factor of image	733	C<$center_x> and C<$center_y> (specified as factor of image width/height).
716	width/height).
717		734
718	#TODO# new width, height, maybe more operators?
719
720	Example: rotate the image by 90 degrees	735	Example: rotate the image by 90 degrees around it's center.
		736
		737	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
721		738
722	=cut	739	=cut
723		740
724	sub rotate($$$$) {	741	sub rotate($$$$) {
725	my $img = pop;	742	my $img = pop;
…		…
877	Scalar::Util::weaken $frame;	894	Scalar::Util::weaken $frame;
878	$self->compile_frame ($frame, sub {	895	$self->compile_frame ($frame, sub {
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 $frame->[FR_CACHE];
882	}
883
884	unless ($self->{term}) {
885	use Data::Dump;
886	ddx $frame;
887	exit;
888	}	899	}
889		900
890	$self->recalculate;	901	$self->recalculate;
891	});	902	});
892	};	903	};

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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 1.64 by root, Tue Jun 19 20:49:53 2012 UTC

Diff Legend

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.63 by root, Tue Jun 19 18:17:56 2012 UTC vs.
Revision 1.64 by root, Tue Jun 19 20:49:53 2012 UTC