[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 1.73 by sf-exg, Thu Jul 5 20:05:19 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	terminal 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 again
		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 COLOUR SPECIFICATIONS
142		163
143	=head3 C<load> et al.	164	Whenever an operator expects a "colour", then this can be specified in one
		165	of two ways: Either as string with an X11 colour specification, such as:
144		166
145	As has been mentioned before, the expression might be evaluated multiple	167	"red" # named colour
146	times. Each time the expression is reevaluated, a new cycle is said to	168	"#f00" # simple rgb
147	have begun. Many operators cache their results till the next cycle.	169	"[50]red" # red with 50% alpha
		170	"TekHVC:300/50/50" # anything goes
148		171
149	For example, the C<load> operator keeps a copy of the image. If it is	172	OR as an array reference with one, three or four components:
150	asked to load the same image on the next cycle it will not load it again,
151	but return the cached copy.
152		173
153	This only works for one cycle though, so as long as you load the same	174	[0.5] # 50% gray, 100% alpha
154	image every time, it will always be cached, but when you load a different	175	[0.5, 0, 0] # dark red, no green or blur, 100% alpha
155	image, it will forget about the first one.	176	[0.5, 0, 0, 0.7] # same with explicit 70% alpha
156		177
157	This allows you to either speed things up by keeping multiple images in	178	=head2 CACHING AND SENSITIVITY
158	memory, or conserve memory by loading images more often.
159		179
160	For example, you can keep two images in memory and use a random one like	180	Since some operations (such as C<load> and C<blur>) can take a long time,
161	this:	181	caching results can be very important for a smooth operation. Caching can
		182	also be useful to reduce memory usage, though, for example, when an image
		183	is cached by C<load>, it could be shared by multiple terminal windows
		184	running inside urxvtd.
162		185
163	my $img1 = load "img1.png";	186	=head3 C<keep { ... }> caching
164	my $img2 = load "img2.png";
165	(0.5 > rand) ? $img1 : $img2
166		187
167	Since both images are "loaded" every time the expression is evaluated,	188	The most important way to cache expensive operations is to use C<keep {
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<{}>	189	... }>. The C<keep> operator takes a block of multiple statements enclosed
182	and evaluates it only.. once, returning any images the last statement	190	by C<{}> and keeps the return value in memory.
183	returned. Further calls simply produce the values from the cache.
184		191
		192	An expression can be "sensitive" to various external events, such as
		193	scaling or moving the window, root background changes and timers. Simply
		194	using an expression (such as C<scale> without parameters) that depends on
		195	certain changing values (called "variables"), or using those variables
		196	directly, will make an expression sensitive to these events - for example,
		197	using C<scale> or C<TW> will make the expression sensitive to the terminal
		198	size, and thus to resizing events.
		199
		200	When such an event happens, C<keep> will automatically trigger a
		201	reevaluation of the whole expression with the new value of the expression.
		202
185	This is most useful for expensive operations, such as C<blur>:	203	C<keep> is most useful for expensive operations, such as C<blur>:
186		204
187	rootalign once { blur 20, root }	205	rootalign keep { blur 20, root }
188		206
189	This makes a blurred copy of the root background once, and on subsequent	207	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	208	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	209	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	210	blurred pixmap) with speed (blur only needs to be redone when root
193	changes).	211	changes).
		212
		213	=head3 C<load> caching
		214
		215	The C<load> operator itself does not keep images in memory, but as long as
		216	the image is still in memory, C<load> will use the in-memory image instead
		217	of loading it freshly from disk.
		218
		219	That means that this expression:
		220
		221	keep { load "$HOME/path..." }
		222
		223	Not only caches the image in memory, other terminal instances that try to
		224	C<load> it can reuse that in-memory copy.
194		225
195	=head1 REFERENCE	226	=head1 REFERENCE
196		227
197	=head2 COMMAND LINE SWITCHES	228	=head2 COMMAND LINE SWITCHES
198		229
…		…
252	=item load $path	283	=item load $path
253		284
254	Loads the image at the given C<$path>. The image is set to plane tiling	285	Loads the image at the given C<$path>. The image is set to plane tiling
255	mode.	286	mode.
256		287
257	Loaded images will be cached for one cycle, and shared between temrinals	288	If the image is already in memory (e.g. because another terminal instance
258	running in the same process (e.g. in C<urxvtd>).	289	uses it), then the in-memory copy us returned instead.
259		290
260	#=item load_uc $path	291	=item load_uc $path
261	#	292
262	#Load uncached - same as load, but does not cache the image. This function	293	Load uncached - same as load, but does not cache the image, which means it
263	#is most useufl if you want to optimise a background expression in some	294	is I<always> loaded from the filesystem again, even if another copy of it
264	#way.	295	is in memory at the time.
265		296
266	=cut	297	=cut
		298
		299	sub load_uc($) {
		300	$self->new_img_from_file ($_[0])
		301	}
267		302
268	sub load($) {	303	sub load($) {
269	my ($path) = @_;	304	my ($path) = @_;
270		305
271	$_IMG_CACHE{$path} \|\| do {	306	$_IMG_CACHE{$path} \|\| do {
272	my $img = $self->new_img_from_file ($path);	307	my $img = load_uc $path;
273	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);	308	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
274	$img	309	$img
275	}	310	}
276	}	311	}
277		312
…		…
323		358
324	=item merge $img ...	359	=item merge $img ...
325		360
326	Takes any number of images and merges them together, creating a single	361	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	362	image containing them all. The tiling mode of the first image is used as
328	the tiling mdoe of the resulting image.	363	the tiling mode of the resulting image.
329		364
330	This function is called automatically when an expression returns multiple	365	This function is called automatically when an expression returns multiple
331	images.	366	images.
332		367
333	=cut	368	=cut
…		…
468	Using these functions make your expression sensitive to window moves.	503	Using these functions make your expression sensitive to window moves.
469		504
470	These functions are mainly useful to align images to the root window.	505	These functions are mainly useful to align images to the root window.
471		506
472	Example: load an image and align it so it looks as if anchored to the	507	Example: load an image and align it so it looks as if anchored to the
473	background.	508	background (that's exactly what C<rootalign> does btw.):
474		509
475	move -TX, -TY, load "mybg.png"	510	move -TX, -TY, keep { load "mybg.png" }
476		511
477	=item TW	512	=item TW
478		513
479	Return the width (C<TW>) and height (C<TH>) of the terminal window (the	514	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	515	terminal window is the full window by default, and the character area only
…		…
486	the window size to conserve memory.	521	the window size to conserve memory.
487		522
488	Example: take the screen background, clip it to the window size, blur it a	523	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.	524	bit, align it to the window position and use it as background.
490		525
491	clip move -TX, -TY, once { blur 5, root }	526	clip move -TX, -TY, keep { blur 5, root }
492		527
493	=cut	528	=cut
494		529
495	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }	530	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
496	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }	531	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
…		…
510	C<$seconds> seconds.	545	C<$seconds> seconds.
511		546
512	Example: load some image and rotate it according to the time of day (as if it were	547	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.	548	the hour pointer of a clock). Update this image every minute.
514		549
		550	again 60;
515	again 60; rotate 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"	551	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
516		552
517	=item counter $seconds	553	=item counter $seconds
518		554
519	Like C<again>, but also returns an increasing counter value, starting at	555	Like C<again>, but also returns an increasing counter value, starting at
520	0, which might be useful for some simple animation effects.	556	0, which might be useful for some simple animation effects.
…		…
557	assumed.	593	assumed.
558		594
559	Example: load an image, blur it, and clip it to the window size to save	595	Example: load an image, blur it, and clip it to the window size to save
560	memory.	596	memory.
561		597
562	clip blur 10, load "mybg.png"	598	clip keep { blur 10, load "mybg.png" }
563		599
564	=cut	600	=cut
565		601
566	sub clip($;$$;$$) {	602	sub clip($;$$;$$) {
567	my $img = pop;	603	my $img = pop;
…		…
661	the terminal window (or the box specified by C<$width> and C<$height> if	697	the terminal window (or the box specified by C<$width> and C<$height> if
662	given).	698	given).
663		699
664	Example: load an image and center it.	700	Example: load an image and center it.
665		701
666	center pad load "mybg.png"	702	center keep { pad load "mybg.png" }
667		703
668	=item rootalign $img	704	=item rootalign $img
669		705
670	Moves the image so that it appears glued to the screen as opposed to the	706	Moves the image so that it appears glued to the screen as opposed to the
671	window. This gives the illusion of a larger area behind the window. It is	707	window. This gives the illusion of a larger area behind the window. It is
672	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	708	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
673	top left of the screen.	709	top left of the screen.
674		710
675	Example: load a background image, put it in mirror mode and root align it.	711	Example: load a background image, put it in mirror mode and root align it.
676		712
677	rootalign mirror load "mybg.png"	713	rootalign keep { mirror load "mybg.png" }
678		714
679	Example: take the screen background and align it, giving the illusion of	715	Example: take the screen background and align it, giving the illusion of
680	transparency as long as the window isn't in front of other windows.	716	transparency as long as the window isn't in front of other windows.
681		717
682	rootalign root	718	rootalign root
…		…
707		743
708	sub rootalign($) {	744	sub rootalign($) {
709	move -TX, -TY, $_[0]	745	move -TX, -TY, $_[0]
710	}	746	}
711		747
712	=item rotate $center_x, $center_y, $degrees	748	=item rotate $center_x, $center_y, $degrees, $img
713		749
714	Rotates the image by C<$degrees> degrees, counter-clockwise, around the	750	Rotates the image clockwise by C<$degrees> degrees, around the point at
715	pointer at C<$center_x> and C<$center_y> (specified as factor of image	751	C<$center_x> and C<$center_y> (specified as factor of image width/height).
716	width/height).
717		752
718	#TODO# new width, height, maybe more operators?
719
720	Example: rotate the image by 90 degrees	753	Example: rotate the image by 90 degrees around it's center.
		754
		755	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
721		756
722	=cut	757	=cut
723		758
724	sub rotate($$$$) {	759	sub rotate($$$$) {
725	my $img = pop;	760	my $img = pop;
…		…
736		771
737	The following operators change the pixels of the image.	772	The following operators change the pixels of the image.
738		773
739	=over 4	774	=over 4
740		775
		776	=item tint $color, $img
		777
		778	Tints the image in the given colour.
		779
		780	Example: tint the image red.
		781
		782	tint "red", load "rgb.png"
		783
		784	Example: the same, but specify the colour by component.
		785
		786	tint [1, 0, 0], load "rgb.png"
		787
		788	=cut
		789
		790	sub tint($$) {
		791	$_[1]->tint ($_[0])
		792	}
		793
741	=item contrast $factor, $img	794	=item contrast $factor, $img
742		795
743	=item contrast $r, $g, $b, $img	796	=item contrast $r, $g, $b, $img
744		797
745	=item contrast $r, $g, $b, $a, $img	798	=item contrast $r, $g, $b, $a, $img
…		…
828	Anything that didn't fit any of the other categories, even after applying	881	Anything that didn't fit any of the other categories, even after applying
829	force and closing our eyes.	882	force and closing our eyes.
830		883
831	=over 4	884	=over 4
832		885
833	=item once { ... }	886	=item keep { ... }
834		887
835	This function takes a code block as argument, that is, one or more	888	This operator takes a code block as argument, that is, one or more
836	statements enclosed by braces.	889	statements enclosed by braces.
837		890
838	The trick is that this code block is only evaluated once - future calls	891	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	892	changes - on other calls the C<keep> simply returns the image it computed
840	images).	893	previously (yes, it should only be used with images). Or in other words,
		894	C<keep> I<caches> the result of the code block so it doesn't need to be
		895	computed again.
841		896
842	This can be extremely useful to avoid redoing the same slow operations	897	This can be extremely useful to avoid redoing slow operations - for
843	again and again- for example, if your background expression takes the root	898	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	899	and then root-aligns it it would have to blur the root background on every
845	root background on every window move or resize.	900	window move or resize.
		901
		902	Another example is C<load>, which can be quite slow.
846		903
847	In fact, urxvt itself encloses the whole expression in some kind of	904	In fact, urxvt itself encloses the whole expression in some kind of
848	C<once> block so it only is reevaluated as required.	905	C<keep> block so it only is reevaluated as required.
849		906
850	Putting the blur into a C<once> block will make sure the blur is only done	907	Putting the blur into a C<keep> block will make sure the blur is only done
851	once:	908	once, while the C<rootalign> is still done each time the window moves.
852		909
853	rootlign once { blur 10, root }	910	rootalign keep { blur 10, root }
854		911
855	This leaves the question of how to force reevaluation of the block,	912	This leaves the question of how to force reevaluation of the block,
856	in case the root background changes: If expression inside the block	913	in case the root background changes: If expression inside the block
857	is sensitive to some event (root background changes, window geometry	914	is sensitive to some event (root background changes, window geometry
858	changes), then it will be reevaluated automatically as needed.	915	changes), then it will be reevaluated automatically as needed.
859		916
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	917	=cut
866		918
867	sub once(&) {	919	sub keep(&) {
868	my $id = $_[0]+0;	920	my $id = $_[0]+0;
869		921
870	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];	922	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
871		923
872	unless ($frame->[FR_CACHE]) {	924	unless ($frame->[FR_CACHE]) {
…		…
879	# clear this frame cache, also for all parents	931	# clear this frame cache, also for all parents
880	for (my $frame = $frame; $frame; $frame = $frame->[0]) {	932	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
881	undef $frame->[FR_CACHE];	933	undef $frame->[FR_CACHE];
882	}	934	}
883		935
884	unless ($self->{term}) {
885	use Data::Dump;
886	ddx $frame;
887	exit;
888	}
889
890	$self->recalculate;	936	$self->recalculate;
891	});	937	});
892	};	938	};
893		939
894	# in scalar context we always return the first original result, which	940	# in scalar context we always return the first original result, which
…		…
896	wantarray	942	wantarray
897	? @{ $frame->[FR_CACHE] }	943	? @{ $frame->[FR_CACHE] }
898	: $frame->[FR_CACHE][0]	944	: $frame->[FR_CACHE][0]
899	}	945	}
900		946
901	sub once_again() {	947	# sub keep_clear() {
902	delete $self->{frame_cache};	948	# delete $self->{frame_cache};
903	}	949	# }
904		950
905	=back	951	=back
906		952
907	=cut	953	=cut
908		954

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.63 by root, Tue Jun 19 18:17:56 2012 UTC vs. Revision 1.73 by sf-exg, Thu Jul 5 20:05:19 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 1.73 by sf-exg, Thu Jul 5 20:05:19 2012 UTC