[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 1.86 by sf-exg, Fri Oct 4 17:09:57 2013 UTC

…		…
4	#:META:X_RESOURCE:%.border:boolean:respect the terminal border	4	#:META:X_RESOURCE:%.border:boolean:respect the terminal border
5	#:META:X_RESOURCE:%.interval:seconds:minimum time between updates	5	#:META:X_RESOURCE:%.interval:seconds:minimum time between updates
6		6
7	=head1 NAME	7	=head1 NAME
8		8
9	background - manage terminal background	9	background - manage terminal background
10		10
11	=head1 SYNOPSIS	11	=head1 SYNOPSIS
12		12
13	urxvt --background-expr 'background expression'	13	urxvt --background-expr 'background expression'
14	--background-border	14	--background-border
15	--background-interval seconds	15	--background-interval seconds
16		16
		17	=head1 QUICK AND DIRTY CHEAT SHEET
		18
		19	Just load a random jpeg image and tile the background with it without
		20	scaling or anything else:
		21
		22	load "/path/to/img.jpg"
		23
		24	The same, but use mirroring/reflection instead of tiling:
		25
		26	mirror load "/path/to/img.jpg"
		27
		28	Load an image and scale it to exactly fill the terminal window:
		29
		30	scale keep { load "/path/to/img.jpg" }
		31
		32	Implement pseudo-transparency by using a suitably-aligned root pixmap
		33	as window background:
		34
		35	rootalign root
		36
		37	Likewise, but keep a blurred copy:
		38
		39	rootalign keep { blur 10, root }
		40
17	=head1 DESCRIPTION	41	=head1 DESCRIPTION
18		42
19	This extension manages the terminal background by creating a picture that	43	This extension manages the terminal background by creating a picture that
20	is behind the text, replacing the normal background colour.	44	is behind the text, replacing the normal background colour.
21		45
…		…
26	to be as simple as possible.	50	to be as simple as possible.
27		51
28	For example, to load an image and scale it to the window size, you would	52	For example, to load an image and scale it to the window size, you would
29	use:	53	use:
30		54
31	urxvt --background-expr 'scale load "/path/to/mybg.png"'	55	urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
32		56
33	Or specified as a X resource:	57	Or specified as a X resource:
34		58
35	URxvt.background-expr: scale load "/path/to/mybg.png"	59	URxvt.background-expr: scale keep { load "/path/to/mybg.png" }
36		60
37	=head1 THEORY OF OPERATION	61	=head1 THEORY OF OPERATION
38		62
39	At startup, just before the window is mapped for the first time, the	63	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	64	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	77	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	78	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	79	pixmap is replaced by another one the root background changes; or when the
56	timer elapses), then the expression will be evaluated again.	80	timer elapses), then the expression will be evaluated again.
57		81
58	For example, an expression such as C<scale load "$HOME/mybg.png"> scales the	82	For example, an expression such as C<scale keep { load "$HOME/mybg.png"
59	image to the window size, so it relies on the window size and will	83	}> 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	84	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	85	example. That ensures that the picture always fills the terminal, even
62	after its size changes.	86	after its size changes.
63		87
64	=head2 EXPRESSIONS	88	=head2 EXPRESSIONS
65		89
66	Expressions are normal Perl expressions, in fact, they are Perl blocks -	90	Expressions are normal Perl expressions, in fact, they are Perl blocks -
67	which means you could use multiple lines and statements:	91	which means you could use multiple lines and statements:
68		92
		93	scale keep {
69	again 3600;	94	again 3600;
70	if (localtime now)[6]) {	95	if (localtime now)[6]) {
71	return scale load "$HOME/weekday.png";	96	return load "$HOME/weekday.png";
72	} else {	97	} else {
73	return scale load "$HOME/sunday.png";	98	return load "$HOME/sunday.png";
		99	}
74	}	100	}
75		101
76	This expression is evaluated once per hour. It will set F<sunday.png> as	102	This inner expression is evaluated once per hour (and whenever the
		103	terminal window is resized). It sets F<sunday.png> as background on
77	background on Sundays, and F<weekday.png> on all other days.	104	Sundays, and F<weekday.png> on all other days.
78		105
79	Fortunately, we expect that most expressions will be much simpler, with	106	Fortunately, we expect that most expressions will be much simpler, with
80	little Perl knowledge needed.	107	little Perl knowledge needed.
81		108
82	Basically, you always start with a function that "generates" an image	109	Basically, you always start with a function that "generates" an image
…		…
115	horizontal and vertical dimensions. For example, this halves the image	142	horizontal and vertical dimensions. For example, this halves the image
116	width and doubles the image height:	143	width and doubles the image height:
117		144
118	scale 0.5, 2, load "$HOME/mypic.png"	145	scale 0.5, 2, load "$HOME/mypic.png"
119		146
120	Other effects than scaling are also readily available, for example, you can	147	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:	148	because each time the terminal is resized, it loads the PNG image again
		149	and scales it. Scaling is usually fast (and unavoidable), but loading the
		150	image can be quite time consuming. This is where C<keep> comes in handy:
122		151
		152	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		153
		154	The C<keep> operator executes all the statements inside the braces only
		155	once, or when it thinks the outcome might change. In other cases it
		156	returns the last value computed by the brace block.
		157
		158	This means that the C<load> is only executed once, which makes it much
		159	faster, but also means that more memory is being used, because the loaded
		160	image must be kept in memory at all times. In this expression, the
		161	trade-off is likely worth it.
		162
		163	But back to effects: Other effects than scaling are also readily
		164	available, for example, you can tile the image to fill the whole window,
		165	instead of resizing it:
		166
123	tile load "$HOME/mypic.png"	167	tile keep { load "$HOME/mypic.png" }
124		168
125	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator	169	In fact, images returned by C<load> are in C<tile> mode by default, so the
126	is kind of superfluous.	170	C<tile> operator is kind of superfluous.
127		171
128	Another common effect is to mirror the image, so that the same edges touch:	172	Another common effect is to mirror the image, so that the same edges
		173	touch:
129		174
130	mirror load "$HOME/mypic.png"	175	mirror keep { load "$HOME/mypic.png" }
131		176
132	This is also a typical background expression:	177	Another common background expression is:
133		178
134	rootalign root	179	rootalign root
135		180
136	It first takes a snapshot of the screen background image, and then	181	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	182	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	183	left corner of the terminal window)- the result is pseudo-transparency:
139	moved around.	184	the image seems to be static while the window is moved around.
140		185
141	=head2 CYCLES AND CACHING	186	=head2 COLOUR SPECIFICATIONS
142		187
143	=head3 C<load> et al.	188	Whenever an operator expects a "colour", then this can be specified in one
		189	of two ways: Either as string with an X11 colour specification, such as:
144		190
145	As has been mentioned before, the expression might be evaluated multiple	191	"red" # named colour
146	times. Each time the expression is reevaluated, a new cycle is said to	192	"#f00" # simple rgb
147	have begun. Many operators cache their results till the next cycle.	193	"[50]red" # red with 50% alpha
		194	"TekHVC:300/50/50" # anything goes
148		195
149	For example, the C<load> operator keeps a copy of the image. If it is	196	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		197
153	This only works for one cycle though, so as long as you load the same	198	[0.5] # 50% gray, 100% alpha
154	image every time, it will always be cached, but when you load a different	199	[0.5, 0, 0] # dark red, no green or blur, 100% alpha
155	image, it will forget about the first one.	200	[0.5, 0, 0, 0.7] # same with explicit 70% alpha
156		201
157	This allows you to either speed things up by keeping multiple images in	202	=head2 CACHING AND SENSITIVITY
158	memory, or conserve memory by loading images more often.
159		203
160	For example, you can keep two images in memory and use a random one like	204	Since some operations (such as C<load> and C<blur>) can take a long time,
161	this:	205	caching results can be very important for a smooth operation. Caching can
		206	also be useful to reduce memory usage, though, for example, when an image
		207	is cached by C<load>, it could be shared by multiple terminal windows
		208	running inside urxvtd.
162		209
163	my $img1 = load "img1.png";	210	=head3 C<keep { ... }> caching
164	my $img2 = load "img2.png";
165	(0.5 > rand) ? $img1 : $img2
166		211
167	Since both images are "loaded" every time the expression is evaluated,	212	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<{}>	213	... }>. The C<keep> operator takes a block of multiple statements enclosed
182	and evaluates it only.. once, returning any images the last statement	214	by C<{}> and keeps the return value in memory.
183	returned. Further calls simply produce the values from the cache.
184		215
		216	An expression can be "sensitive" to various external events, such as
		217	scaling or moving the window, root background changes and timers. Simply
		218	using an expression (such as C<scale> without parameters) that depends on
		219	certain changing values (called "variables"), or using those variables
		220	directly, will make an expression sensitive to these events - for example,
		221	using C<scale> or C<TW> will make the expression sensitive to the terminal
		222	size, and thus to resizing events.
		223
		224	When such an event happens, C<keep> will automatically trigger a
		225	reevaluation of the whole expression with the new value of the expression.
		226
185	This is most useful for expensive operations, such as C<blur>:	227	C<keep> is most useful for expensive operations, such as C<blur>:
186		228
187	rootalign once { blur 20, root }	229	rootalign keep { blur 20, root }
188		230
189	This makes a blurred copy of the root background once, and on subsequent	231	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	232	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	233	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	234	blurred pixmap) with speed (blur only needs to be redone when root
193	changes).	235	changes).
		236
		237	=head3 C<load> caching
		238
		239	The C<load> operator itself does not keep images in memory, but as long as
		240	the image is still in memory, C<load> will use the in-memory image instead
		241	of loading it freshly from disk.
		242
		243	That means that this expression:
		244
		245	keep { load "$HOME/path..." }
		246
		247	Not only caches the image in memory, other terminal instances that try to
		248	C<load> it can reuse that in-memory copy.
194		249
195	=head1 REFERENCE	250	=head1 REFERENCE
196		251
197	=head2 COMMAND LINE SWITCHES	252	=head2 COMMAND LINE SWITCHES
198		253
…		…
224	=cut	279	=cut
225		280
226	our %_IMG_CACHE;	281	our %_IMG_CACHE;
227	our $HOME;	282	our $HOME;
228	our ($self, $frame);	283	our ($self, $frame);
229	our ($x, $y, $w, $h);	284	our ($x, $y, $w, $h, $focus);
230		285
231	# enforce at least this interval between updates	286	# enforce at least this interval between updates
232	our $MIN_INTERVAL = 6/59.951;	287	our $MIN_INTERVAL = 6/59.951;
233		288
234	{	289	{
…		…
252	=item load $path	307	=item load $path
253		308
254	Loads the image at the given C<$path>. The image is set to plane tiling	309	Loads the image at the given C<$path>. The image is set to plane tiling
255	mode.	310	mode.
256		311
257	Loaded images will be cached for one cycle, and shared between temrinals	312	If the image is already in memory (e.g. because another terminal instance
258	running in the same process (e.g. in C<urxvtd>).	313	uses it), then the in-memory copy is returned instead.
259		314
260	#=item load_uc $path	315	=item load_uc $path
261	#	316
262	#Load uncached - same as load, but does not cache the image. This function	317	Load uncached - same as load, but does not cache the image, which means it
263	#is most useufl if you want to optimise a background expression in some	318	is I<always> loaded from the filesystem again, even if another copy of it
264	#way.	319	is in memory at the time.
265		320
266	=cut	321	=cut
		322
		323	sub load_uc($) {
		324	$self->new_img_from_file ($_[0])
		325	}
267		326
268	sub load($) {	327	sub load($) {
269	my ($path) = @_;	328	my ($path) = @_;
270		329
271	$_IMG_CACHE{$path} \|\| do {	330	$_IMG_CACHE{$path} \|\| do {
272	my $img = $self->new_img_from_file ($path);	331	my $img = load_uc $path;
273	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);	332	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
274	$img	333	$img
275	}	334	}
276	}	335	}
277		336
…		…
323		382
324	=item merge $img ...	383	=item merge $img ...
325		384
326	Takes any number of images and merges them together, creating a single	385	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	386	image containing them all. The tiling mode of the first image is used as
328	the tiling mdoe of the resulting image.	387	the tiling mode of the resulting image.
329		388
330	This function is called automatically when an expression returns multiple	389	This function is called automatically when an expression returns multiple
331	images.	390	images.
332		391
333	=cut	392	=cut
…		…
362	$base->draw ($_)	421	$base->draw ($_)
363	for @_;	422	for @_;
364		423
365	$base	424	$base
366	}	425	}
		426
		427	=back
367		428
368	=head2 TILING MODES	429	=head2 TILING MODES
369		430
370	The following operators modify the tiling mode of an image, that is, the	431	The following operators modify the tiling mode of an image, that is, the
371	way that pixels outside the image area are painted when the image is used.	432	way that pixels outside the image area are painted when the image is used.
…		…
463		524
464	Return the X and Y coordinates of the terminal window (the terminal	525	Return the X and Y coordinates of the terminal window (the terminal
465	window is the full window by default, and the character area only when in	526	window is the full window by default, and the character area only when in
466	border-respect mode).	527	border-respect mode).
467		528
468	Using these functions make your expression sensitive to window moves.	529	Using these functions makes your expression sensitive to window moves.
469		530
470	These functions are mainly useful to align images to the root window.	531	These functions are mainly useful to align images to the root window.
471		532
472	Example: load an image and align it so it looks as if anchored to the	533	Example: load an image and align it so it looks as if anchored to the
473	background.	534	background (that's exactly what C<rootalign> does btw.):
474		535
475	move -TX, -TY, load "mybg.png"	536	move -TX, -TY, keep { load "mybg.png" }
476		537
477	=item TW	538	=item TW
		539
		540	=item TH
478		541
479	Return the width (C<TW>) and height (C<TH>) of the terminal window (the	542	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	543	terminal window is the full window by default, and the character area only
481	when in border-respect mode).	544	when in border-respect mode).
482		545
483	Using these functions make your expression sensitive to window resizes.	546	Using these functions makes your expression sensitive to window resizes.
484		547
485	These functions are mainly useful to scale images, or to clip images to	548	These functions are mainly useful to scale images, or to clip images to
486	the window size to conserve memory.	549	the window size to conserve memory.
487		550
488	Example: take the screen background, clip it to the window size, blur it a	551	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.	552	bit, align it to the window position and use it as background.
490		553
491	clip move -TX, -TY, once { blur 5, root }	554	clip move -TX, -TY, keep { blur 5, root }
492		555
493	=cut	556	=item FOCUS
494		557
		558	Returns a boolean indicating whether the terminal window has keyboard
		559	focus, in which case it returns true.
		560
		561	Using this function makes your expression sensitive to focus changes.
		562
		563	A common use case is to fade the background image when the terminal loses
		564	focus, often together with the C<-fade> command line option. In fact,
		565	there is a special function for just that use case: C<focus_fade>.
		566
		567	Example: use two entirely different background images, depending on
		568	whether the window has focus.
		569
		570	FOCUS ? keep { load "has_focus.jpg" } : keep { load "no_focus.jpg" }
		571
		572	=cut
		573
495	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }	574	sub TX () { $frame->[FR_AGAIN]{position} = 1; $x }
496	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }	575	sub TY () { $frame->[FR_AGAIN]{position} = 1; $y }
497	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }	576	sub TW () { $frame->[FR_AGAIN]{size} = 1; $w }
498	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }	577	sub TH () { $frame->[FR_AGAIN]{size} = 1; $h }
		578	sub FOCUS() { $frame->[FR_AGAIN]{focus} = 1; $focus }
499		579
500	=item now	580	=item now
501		581
502	Returns the current time as (fractional) seconds since the epoch.	582	Returns the current time as (fractional) seconds since the epoch.
503		583
…		…
510	C<$seconds> seconds.	590	C<$seconds> seconds.
511		591
512	Example: load some image and rotate it according to the time of day (as if it were	592	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.	593	the hour pointer of a clock). Update this image every minute.
514		594
		595	again 60;
515	again 60; rotate 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"	596	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
516		597
517	=item counter $seconds	598	=item counter $seconds
518		599
519	Like C<again>, but also returns an increasing counter value, starting at	600	Like C<again>, but also returns an increasing counter value, starting at
520	0, which might be useful for some simple animation effects.	601	0, which might be useful for some simple animation effects.
…		…
549	Clips an image to the given rectangle. If the rectangle is outside the	630	Clips an image to the given rectangle. If the rectangle is outside the
550	image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is	631	image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is
551	larger than the image, then the tiling mode defines how the extra pixels	632	larger than the image, then the tiling mode defines how the extra pixels
552	will be filled.	633	will be filled.
553		634
554	If C<$x> an C<$y> are missing, then C<0> is assumed for both.	635	If C<$x> and C<$y> are missing, then C<0> is assumed for both.
555		636
556	If C<$width> and C<$height> are missing, then the window size will be	637	If C<$width> and C<$height> are missing, then the window size will be
557	assumed.	638	assumed.
558		639
559	Example: load an image, blur it, and clip it to the window size to save	640	Example: load an image, blur it, and clip it to the window size to save
560	memory.	641	memory.
561		642
562	clip blur 10, load "mybg.png"	643	clip keep { blur 10, load "mybg.png" }
563		644
564	=cut	645	=cut
565		646
566	sub clip($;$$;$$) {	647	sub clip($;$$;$$) {
567	my $img = pop;	648	my $img = pop;
…		…
577	=item scale $width_factor, $height_factor, $img	658	=item scale $width_factor, $height_factor, $img
578		659
579	Scales the image by the given factors in horizontal	660	Scales the image by the given factors in horizontal
580	(C<$width>) and vertical (C<$height>) direction.	661	(C<$width>) and vertical (C<$height>) direction.
581		662
582	If only one factor is give, it is used for both directions.	663	If only one factor is given, it is used for both directions.
583		664
584	If no factors are given, scales the image to the window size without	665	If no factors are given, scales the image to the window size without
585	keeping aspect.	666	keeping aspect.
586		667
587	=item resize $width, $height, $img	668	=item resize $width, $height, $img
…		…
661	the terminal window (or the box specified by C<$width> and C<$height> if	742	the terminal window (or the box specified by C<$width> and C<$height> if
662	given).	743	given).
663		744
664	Example: load an image and center it.	745	Example: load an image and center it.
665		746
666	center pad load "mybg.png"	747	center keep { pad load "mybg.png" }
667		748
668	=item rootalign $img	749	=item rootalign $img
669		750
670	Moves the image so that it appears glued to the screen as opposed to the	751	Moves the image so that it appears glued to the screen as opposed to the
671	window. This gives the illusion of a larger area behind the window. It is	752	window. This gives the illusion of a larger area behind the window. It is
672	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	753	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
673	top left of the screen.	754	top left of the screen.
674		755
675	Example: load a background image, put it in mirror mode and root align it.	756	Example: load a background image, put it in mirror mode and root align it.
676		757
677	rootalign mirror load "mybg.png"	758	rootalign keep { mirror load "mybg.png" }
678		759
679	Example: take the screen background and align it, giving the illusion of	760	Example: take the screen background and align it, giving the illusion of
680	transparency as long as the window isn't in front of other windows.	761	transparency as long as the window isn't in front of other windows.
681		762
682	rootalign root	763	rootalign root
…		…
707		788
708	sub rootalign($) {	789	sub rootalign($) {
709	move -TX, -TY, $_[0]	790	move -TX, -TY, $_[0]
710	}	791	}
711		792
712	=item rotate $center_x, $center_y, $degrees	793	=item rotate $center_x, $center_y, $degrees, $img
713		794
714	Rotates the image by C<$degrees> degrees, counter-clockwise, around the	795	Rotates the image clockwise by C<$degrees> degrees, around the point at
715	pointer at C<$center_x> and C<$center_y> (specified as factor of image	796	C<$center_x> and C<$center_y> (specified as factor of image width/height).
716	width/height).
717		797
718	#TODO# new width, height, maybe more operators?
719
720	Example: rotate the image by 90 degrees	798	Example: rotate the image by 90 degrees around its center.
		799
		800	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
721		801
722	=cut	802	=cut
723		803
724	sub rotate($$$$) {	804	sub rotate($$$$) {
725	my $img = pop;	805	my $img = pop;
…		…
736		816
737	The following operators change the pixels of the image.	817	The following operators change the pixels of the image.
738		818
739	=over 4	819	=over 4
740		820
		821	=item tint $color, $img
		822
		823	Tints the image in the given colour.
		824
		825	Example: tint the image red.
		826
		827	tint "red", load "rgb.png"
		828
		829	Example: the same, but specify the colour by component.
		830
		831	tint [1, 0, 0], load "rgb.png"
		832
		833	=cut
		834
		835	sub tint($$) {
		836	$_[1]->tint ($_[0])
		837	}
		838
		839	=item shade $factor, $img
		840
		841	Shade the image by the given factor.
		842
		843	=cut
		844
		845	sub shade($$) {
		846	$_[1]->shade ($_[0])
		847	}
		848
741	=item contrast $factor, $img	849	=item contrast $factor, $img
742		850
743	=item contrast $r, $g, $b, $img	851	=item contrast $r, $g, $b, $img
744		852
745	=item contrast $r, $g, $b, $a, $img	853	=item contrast $r, $g, $b, $a, $img
…		…
774	latter in a white picture.	882	latter in a white picture.
775		883
776	Due to idiosyncrasies in the underlying XRender extension, biases less	884	Due to idiosyncrasies in the underlying XRender extension, biases less
777	than zero can be I<very> slow.	885	than zero can be I<very> slow.
778		886
		887	You can also try the experimental(!) C<muladd> operator.
		888
779	=cut	889	=cut
780		890
781	sub contrast($$;$$;$) {	891	sub contrast($$;$$;$) {
782	my $img = pop;	892	my $img = pop;
783	my ($r, $g, $b, $a) = @_;	893	my ($r, $g, $b, $a) = @_;
…		…
798	$a = 1 if @_ < 4;	908	$a = 1 if @_ < 4;
799		909
800	$img = $img->clone;	910	$img = $img->clone;
801	$img->brightness ($r, $g, $b, $a);	911	$img->brightness ($r, $g, $b, $a);
802	$img	912	$img
		913	}
		914
		915	=item muladd $mul, $add, $img # EXPERIMENTAL
		916
		917	First multiplies the pixels by C<$mul>, then adds C<$add>. This can be used
		918	to implement brightness and contrast at the same time, with a wider value
		919	range than contrast and brightness operators.
		920
		921	Due to numerous bugs in XRender implementations, it can also introduce a
		922	number of visual artifacts.
		923
		924	Example: increase contrast by a factor of C<$c> without changing image
		925	brightness too much.
		926
		927	muladd $c, (1 - $c) * 0.5, $img
		928
		929	=cut
		930
		931	sub muladd($$$) {
		932	$_[2]->muladd ($_[0], $_[1])
803	}	933	}
804		934
805	=item blur $radius, $img	935	=item blur $radius, $img
806		936
807	=item blur $radius_horz, $radius_vert, $img	937	=item blur $radius_horz, $radius_vert, $img
…		…
819	sub blur($$;$) {	949	sub blur($$;$) {
820	my $img = pop;	950	my $img = pop;
821	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	951	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
822	}	952	}
823		953
		954	=item focus_fade $img
		955
		956	=item focus_fade $factor, $img
		957
		958	=item focus_fade $factor, $color, $img
		959
		960	Fades the image by the given factor (and colour) when focus is lost (the
		961	same as the C<-fade>/C<-fadecolor> command line options, which also supply
		962	the default values for C<factor> and C<$color>. Unlike with C<-fade>, the
		963	C<$factor> is the real value, not a percentage value (that is, 0..1, not
		964	0..100).
		965
		966	Example: do the right thing when focus fading is requested.
		967
		968	focus_fade load "mybg.jpg";
		969
		970	=cut
		971
		972	sub focus_fade($;$$) {
		973	my $img = pop;
		974
		975	return $img
		976	if FOCUS;
		977
		978	my $fade = @_ >= 1 ? $_[0] : defined $self->resource ("fade") ? $self->resource ("fade") * 0.01 : 0;
		979	my $color = @_ >= 2 ? $_[1] : $self->resource ("color+" . urxvt::Color_fade);
		980
		981	$img = $img->tint ($color) if $color ne "rgb:00/00/00";
		982	$img = $img->muladd (1 - $fade, 0) if $fade;
		983
		984	$img
		985	}
		986
824	=back	987	=back
825		988
826	=head2 OTHER STUFF	989	=head2 OTHER STUFF
827		990
828	Anything that didn't fit any of the other categories, even after applying	991	Anything that didn't fit any of the other categories, even after applying
829	force and closing our eyes.	992	force and closing our eyes.
830		993
831	=over 4	994	=over 4
832		995
833	=item once { ... }	996	=item keep { ... }
834		997
835	This function takes a code block as argument, that is, one or more	998	This operator takes a code block as argument, that is, one or more
836	statements enclosed by braces.	999	statements enclosed by braces.
837		1000
838	The trick is that this code block is only evaluated once - future calls	1001	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	1002	changes - on other calls the C<keep> simply returns the image it computed
840	images).	1003	previously (yes, it should only be used with images). Or in other words,
		1004	C<keep> I<caches> the result of the code block so it doesn't need to be
		1005	computed again.
841		1006
842	This can be extremely useful to avoid redoing the same slow operations	1007	This can be extremely useful to avoid redoing slow operations - for
843	again and again- for example, if your background expression takes the root	1008	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	1009	and then root-aligns it it would have to blur the root background on every
845	root background on every window move or resize.	1010	window move or resize.
		1011
		1012	Another example is C<load>, which can be quite slow.
846		1013
847	In fact, urxvt itself encloses the whole expression in some kind of	1014	In fact, urxvt itself encloses the whole expression in some kind of
848	C<once> block so it only is reevaluated as required.	1015	C<keep> block so it only is reevaluated as required.
849		1016
850	Putting the blur into a C<once> block will make sure the blur is only done	1017	Putting the blur into a C<keep> block will make sure the blur is only done
851	once:	1018	once, while the C<rootalign> is still done each time the window moves.
852		1019
853	rootlign once { blur 10, root }	1020	rootalign keep { blur 10, root }
854		1021
855	This leaves the question of how to force reevaluation of the block,	1022	This leaves the question of how to force reevaluation of the block,
856	in case the root background changes: If expression inside the block	1023	in case the root background changes: If expression inside the block
857	is sensitive to some event (root background changes, window geometry	1024	is sensitive to some event (root background changes, window geometry
858	changes), then it will be reevaluated automatically as needed.	1025	changes), then it will be reevaluated automatically as needed.
859		1026
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	1027	=cut
866		1028
867	sub once(&) {	1029	sub keep(&) {
868	my $id = $_[0]+0;	1030	my $id = $_[0]+0;
869		1031
870	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];	1032	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
871		1033
872	unless ($frame->[FR_CACHE]) {	1034	unless ($frame->[FR_CACHE]) {
…		…
879	# clear this frame cache, also for all parents	1041	# clear this frame cache, also for all parents
880	for (my $frame = $frame; $frame; $frame = $frame->[0]) {	1042	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
881	undef $frame->[FR_CACHE];	1043	undef $frame->[FR_CACHE];
882	}	1044	}
883		1045
884	unless ($self->{term}) {
885	use Data::Dump;
886	ddx $frame;
887	exit;
888	}
889
890	$self->recalculate;	1046	$self->recalculate;
891	});	1047	});
892	};	1048	};
893		1049
894	# in scalar context we always return the first original result, which	1050	# in scalar context we always return the first original result, which
…		…
896	wantarray	1052	wantarray
897	? @{ $frame->[FR_CACHE] }	1053	? @{ $frame->[FR_CACHE] }
898	: $frame->[FR_CACHE][0]	1054	: $frame->[FR_CACHE][0]
899	}	1055	}
900		1056
901	sub once_again() {	1057	# sub keep_clear() {
902	delete $self->{frame_cache};	1058	# delete $self->{frame_cache};
903	}	1059	# }
904		1060
905	=back	1061	=back
906		1062
907	=cut	1063	=cut
908		1064
…		…
921		1077
922	# compiles a parsed expression	1078	# compiles a parsed expression
923	sub set_expr {	1079	sub set_expr {
924	my ($self, $expr) = @_;	1080	my ($self, $expr) = @_;
925		1081
926	$self->{root} = [];	1082	$self->{root} = []; # the outermost frame
927	$self->{expr} = $expr;	1083	$self->{expr} = $expr;
928	$self->recalculate;	1084	$self->recalculate;
929	}	1085	}
930		1086
931	# takes a hash of sensitivity indicators and installs watchers	1087	# takes a hash of sensitivity indicators and installs watchers
…		…
972	if ($again->{rootpmap}) {	1128	if ($again->{rootpmap}) {
973	$state->{rootpmap} = $self->on (rootpmap_change => $cb);	1129	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
974	} else {	1130	} else {
975	delete $state->{rootpmap};	1131	delete $state->{rootpmap};
976	}	1132	}
		1133
		1134	if ($again->{focus}) {
		1135	$state->{focus} = $self->on (focus_in => $cb, focus_out => $cb);
		1136	} else {
		1137	delete $state->{focus};
		1138	}
977	}	1139	}
978		1140
979	# evaluate the current bg expression	1141	# evaluate the current bg expression
980	sub recalculate {	1142	sub recalculate {
981	my ($arg_self) = @_;	1143	my ($arg_self) = @_;
…		…
993		1155
994	# set environment to evaluate user expression	1156	# set environment to evaluate user expression
995		1157
996	local $self = $arg_self;	1158	local $self = $arg_self;
997	local $HOME = $ENV{HOME};	1159	local $HOME = $ENV{HOME};
998	local $frame = [];	1160	local $frame = $self->{root};
999		1161
1000	($x, $y, $w, $h) = $self->background_geometry ($self->{border});	1162	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
		1163	$focus = $self->focus;
1001		1164
1002	# evaluate user expression	1165	# evaluate user expression
1003		1166
1004	my @img = eval { $self->{expr}->() };	1167	my @img = eval { $self->{expr}->() };
1005	die $@ if $@;	1168	die $@ if $@;

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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 1.86 by sf-exg, Fri Oct 4 17:09:57 2013 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 1.86 by sf-exg, Fri Oct 4 17:09:57 2013 UTC