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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.38 by root, Fri Jun 8 21:48:07 2012 UTC vs.
Revision 1.53 by root, Tue Jun 12 18:25:57 2012 UTC

…		…
1	#! perl	1	#! perl
2		2
3	#:META:X_RESOURCE:%.expr:string:background expression	3	#:META:X_RESOURCE:%.expr:string:background expression
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		6
6	#TODO: once, rootalign	7	=head1 NAME
7		8
8	=head1 background - manage terminal background	9	background - manage terminal background
9		10
10	=head2 SYNOPSIS	11	=head1 SYNOPSIS
11		12
12	urxvt --background-expr 'background expression'	13	urxvt --background-expr 'background expression'
13	--background-border	14	--background-border
		15	--background-interval seconds
14		16
15	=head2 DESCRIPTION	17	=head1 DESCRIPTION
16		18
17	This extension manages the terminal background by creating a picture that	19	This extension manages the terminal background by creating a picture that
18	is behind the text, replacing the normal background colour.	20	is behind the text, replacing the normal background colour.
19		21
20	It does so by evaluating a Perl expression that I<calculates> the image on	22	It does so by evaluating a Perl expression that I<calculates> the image on
30		32
31	Or specified as a X resource:	33	Or specified as a X resource:
32		34
33	URxvt.background-expr: scale load "/path/to/mybg.png"	35	URxvt.background-expr: scale load "/path/to/mybg.png"
34		36
35	=head2 THEORY OF OPERATION	37	=head1 THEORY OF OPERATION
36		38
37	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
38	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
39	extended as necessary to cover the whole terminal window, and is set as a	41	extended as necessary to cover the whole terminal window, and is set as a
40	background pixmap.	42	background pixmap.
…		…
55		57
56	For example, an expression such as C<scale load "$HOME/mybg.png"> scales the	58	For example, an expression such as C<scale load "$HOME/mybg.png"> scales the
57	image to the window size, so it relies on the window size and will	59	image to the window size, so it relies on the window size and will
58	be reevaluated each time it is changed, but not when it moves for	60	be reevaluated each time it is changed, but not when it moves for
59	example. That ensures that the picture always fills the terminal, even	61	example. That ensures that the picture always fills the terminal, even
60	after it's size changes.	62	after its size changes.
61		63
62	=head3 EXPRESSIONS	64	=head2 EXPRESSIONS
63		65
64	Expressions are normal Perl expressions, in fact, they are Perl blocks -	66	Expressions are normal Perl expressions, in fact, they are Perl blocks -
65	which means you could use multiple lines and statements:	67	which means you could use multiple lines and statements:
66		68
67	again 3600;	69	again 3600;
…		…
70	} else {	72	} else {
71	return scale load "$HOME/sunday.png";	73	return scale load "$HOME/sunday.png";
72	}	74	}
73		75
74	This expression gets evaluated once per hour. It will set F<sunday.png> as	76	This expression gets evaluated once per hour. It will set F<sunday.png> as
75	background on sundays, and F<weekday.png> on all other days.	77	background on Sundays, and F<weekday.png> on all other days.
76		78
77	Fortunately, we expect that most expressions will be much simpler, with	79	Fortunately, we expect that most expressions will be much simpler, with
78	little Perl knowledge needed.	80	little Perl knowledge needed.
79		81
80	Basically, you always start with a function that "generates" an image	82	Basically, you always start with a function that "generates" an image
…		…
97	its result becomes the argument to the C<scale> function.	99	its result becomes the argument to the C<scale> function.
98		100
99	Many operators also allow some parameters preceding the input image	101	Many operators also allow some parameters preceding the input image
100	that modify its behaviour. For example, C<scale> without any additional	102	that modify its behaviour. For example, C<scale> without any additional
101	arguments scales the image to size of the terminal window. If you specify	103	arguments scales the image to size of the terminal window. If you specify
102	an additional argument, it uses it as a percentage:	104	an additional argument, it uses it as a scale factor (multiply by 100 to
		105	get a percentage):
103		106
104	scale 200, load "$HOME/mypic.png"	107	scale 2, load "$HOME/mypic.png"
105		108
106	This enlarges the image by a factor of 2 (200%). As you can see, C<scale>	109	This enlarges the image by a factor of 2 (200%). As you can see, C<scale>
107	has now two arguments, the C<200> and the C<load> expression, while	110	has now two arguments, the C<200> and the C<load> expression, while
108	C<load> only has one argument. Arguments are separated from each other by	111	C<load> only has one argument. Arguments are separated from each other by
109	commas.	112	commas.
110		113
111	Scale also accepts two arguments, which are then separate factors for both	114	Scale also accepts two arguments, which are then separate factors for both
112	horizontal and vertical dimensions. For example, this halves the image	115	horizontal and vertical dimensions. For example, this halves the image
113	width and doubles the image height:	116	width and doubles the image height:
114		117
115	scale 50, 200, load "$HOME/mypic.png"	118	scale 0.5, 2, load "$HOME/mypic.png"
116		119
117	TODO	120	Other effects than scaling are also readily available, for example, you can
		121	tile the image to fill the whole window, instead of resizing it:
118		122
		123	tile load "$HOME/mypic.png"
		124
		125	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator
		126	is kind of superfluous.
		127
		128	Another common effect is to mirror the image, so that the same edges touch:
		129
		130	mirror load "$HOME/mypic.png"
		131
		132	This is also a typical background expression:
		133
		134	rootalign root
		135
		136	It 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
		138	pseudo-transparency, as the image seems to be static while the window is
		139	moved around.
		140
119	=head3 CYCLES AND CACHING	141	=head2 CYCLES AND CACHING
120		142
121	TODO	143	As has been mentioned before, the expression might be evaluated multiple
122
123	Each time the expression is reevaluated, a new cycle is said to have begun. Many operators	144	times. Each time the expression is reevaluated, a new cycle is said to
124	cache their results till the next cycle. For example	145	have begun. Many operators cache their results till the next cycle.
125		146
		147	For example, the C<load> operator keeps a copy of the image. If it is
		148	asked to load the same image on the next cycle it will not load it again,
		149	but return the cached copy.
		150
		151	This only works for one cycle though, so as long as you load the same
		152	image every time, it will always be cached, but when you load a different
		153	image, it will forget about the first one.
		154
		155	This allows you to either speed things up by keeping multiple images in
		156	memory, or conserve memory by loading images more often.
		157
		158	For example, you can keep two images in memory and use a random one like
		159	this:
		160
		161	my $img1 = load "img1.png";
		162	my $img2 = load "img2.png";
		163	(0.5 > rand) ? $img1 : $img2
		164
		165	Since both images are "loaded" every time the expression is evaluated,
		166	they are always kept in memory. Contrast this version:
		167
		168	my $path1 = "img1.png";
		169	my $path2 = "img2.png";
		170	load ((0.5 > rand) ? $path1 : $path2)
		171
		172	Here, a path is selected randomly, and load is only called for one image,
		173	so keeps only one image in memory. If, on the next evaluation, luck
		174	decides to use the other path, then it will have to load that image again.
		175
126	=head2 REFERENCE	176	=head1 REFERENCE
127		177
128	=head3 COMMAND LINE SWITCHES	178	=head2 COMMAND LINE SWITCHES
129		179
130	=over 4	180	=over 4
131		181
132	=item --background-expr perl-expression	182	=item --background-expr perl-expression
133		183
…		…
139	overwriting borders and any other areas, such as the scrollbar.	189	overwriting borders and any other areas, such as the scrollbar.
140		190
141	Specifying this flag changes the behaviour, so that the image only	191	Specifying this flag changes the behaviour, so that the image only
142	replaces the background of the character area.	192	replaces the background of the character area.
143		193
		194	=item --background-interval seconds
		195
		196	Since some operations in the underlying XRender extension can effectively
		197	freeze your X-server for prolonged time, this extension enforces a minimum
		198	time between updates, which is normally about 0.1 seconds.
		199
		200	If you want to do updates more often, you can decrease this safety
		201	interval with this switch.
		202
144	=back	203	=back
145		204
146	=cut	205	=cut
147		206
148	our $EXPR;#d#	207	our %_IMG_CACHE;
149	#$EXPR = 'move W * 0.1, -H * 0.1, resize W * 0.5, H * 0.5, repeat_none load "opensource.png"';	208	our %_ONCE_CACHE;
150	$EXPR = 'move -TX, -TY, load "argb.png"';
151	#$EXPR = '
152	# rotate W, H, 50, 50, counter 1/59.95, repeat_mirror,
153	# clip X, Y, W, H, repeat_mirror,
154	# load "/root/pix/das_fette_schwein.jpg"
155	#';
156	#$EXPR = 'solid "red"';
157	#$EXPR = 'blur root, 10, 10'
158	#$EXPR = 'blur move (root, -x, -y), 5, 5'
159	#resize load "/root/pix/das_fette_schwein.jpg", w, h
160
161	our $HOME;	209	our $HOME;
162	our ($self, $old, $new);	210	our ($self, $old, $new);
163	our ($x, $y, $w, $h);	211	our ($x, $y, $w, $h);
164		212
165	# enforce at least this interval between updates	213	# enforce at least this interval between updates
166	our $MIN_INTERVAL = 1/100;	214	our $MIN_INTERVAL = 6/59.951;
167		215
168	{	216	{
169	package urxvt::bgdsl; # background language	217	package urxvt::bgdsl; # background language
		218
		219	use List::Util qw(min max sum shuffle);
170		220
171	=head2 PROVIDERS/GENERATORS	221	=head2 PROVIDERS/GENERATORS
172		222
173	These functions provide an image, by loading it from disk, grabbing it	223	These functions provide an image, by loading it from disk, grabbing it
174	from the root screen or by simply generating it. They are used as starting	224	from the root screen or by simply generating it. They are used as starting
…		…
201		251
202	=cut	252	=cut
203		253
204	sub root() {	254	sub root() {
205	$new->{rootpmap_sensitive} = 1;	255	$new->{rootpmap_sensitive} = 1;
206	die "root op not supported, exg, we need you";	256	$self->new_img_from_root
207	}	257	}
208		258
209	=item solid $colour	259	=item solid $colour
210		260
211	=item solid $width, $height, $colour	261	=item solid $width, $height, $colour
212		262
213	Creates a new image and completely fills it with the given colour. The	263	Creates a new image and completely fills it with the given colour. The
214	image is set to tiling mode.	264	image is set to tiling mode.
215		265
216	If <$width> and C<$height> are omitted, it creates a 1x1 image, which is	266	If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
217	useful for solid backgrounds or for use in filtering effects.	267	useful for solid backgrounds or for use in filtering effects.
218		268
219	=cut	269	=cut
220		270
221	sub solid($$;$) {	271	sub solid($;$$) {
222	my $colour = pop;	272	my $colour = pop;
223		273
224	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	274	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);
225	$img->fill ($colour);	275	$img->fill ($colour);
226	$img	276	$img
227	}	277	}
228		278
		279	=item clone $img
		280
		281	Returns an exact copy of the image. This is useful if you want to have
		282	multiple copies of the same image to apply different effects to.
		283
		284	=cut
		285
		286	sub clone($) {
		287	$_[0]->clone
		288	}
		289
		290	=head2 TILING MODES
		291
		292	The following operators modify the tiling mode of an image, that is, the
		293	way that pixels outside the image area are painted when the image is used.
		294
		295	=over 4
		296
		297	=item tile $img
		298
		299	Tiles the whole plane with the image and returns this new image - or in
		300	other words, it returns a copy of the image in plane tiling mode.
		301
		302	Example: load an image and tile it over the background, without
		303	resizing. The C<tile> call is superfluous because C<load> already defaults
		304	to tiling mode.
		305
		306	tile load "mybg.png"
		307
		308	=item mirror $img
		309
		310	Similar to tile, but reflects the image each time it uses a new copy, so
		311	that top edges always touch top edges, right edges always touch right
		312	edges and so on (with normal tiling, left edges always touch right edges
		313	and top always touch bottom edges).
		314
		315	Example: load an image and mirror it over the background, avoiding sharp
		316	edges at the image borders at the expense of mirroring the image itself
		317
		318	mirror load "mybg.png"
		319
		320	=item pad $img
		321
		322	Takes an image and modifies it so that all pixels outside the image area
		323	become transparent. This mode is most useful when you want to place an
		324	image over another image or the background colour while leaving all
		325	background pixels outside the image unchanged.
		326
		327	Example: load an image and display it in the upper left corner. The rest
		328	of the space is left "empty" (transparent or whatever your compositor does
		329	in alpha mode, else background colour).
		330
		331	pad load "mybg.png"
		332
		333	=item extend $img
		334
		335	Extends the image over the whole plane, using the closest pixel in the
		336	area outside the image. This mode is mostly useful when you use more complex
		337	filtering operations and want the pixels outside the image to have the
		338	same values as the pixels near the edge.
		339
		340	Example: just for curiosity, how does this pixel extension stuff work?
		341
		342	extend move 50, 50, load "mybg.png"
		343
		344	=cut
		345
		346	sub pad($) {
		347	my $img = $_[0]->clone;
		348	$img->repeat_mode (urxvt::RepeatNone);
		349	$img
		350	}
		351
		352	sub tile($) {
		353	my $img = $_[0]->clone;
		354	$img->repeat_mode (urxvt::RepeatNormal);
		355	$img
		356	}
		357
		358	sub mirror($) {
		359	my $img = $_[0]->clone;
		360	$img->repeat_mode (urxvt::RepeatReflect);
		361	$img
		362	}
		363
		364	sub extend($) {
		365	my $img = $_[0]->clone;
		366	$img->repeat_mode (urxvt::RepeatPad);
		367	$img
		368	}
		369
229	=back	370	=back
230		371
231	=head2 VARIABLES	372	=head2 VARIABLE VALUES
232		373
233	The following functions provide variable data such as the terminal	374	The following functions provide variable data such as the terminal window
		375	dimensions. They are not (Perl-) variables, they just return stuff that
234	window dimensions. Most of them make your expression sensitive to some	376	varies. Most of them make your expression sensitive to some events, for
235	events, for example using C<TW> (terminal width) means your expression is	377	example using C<TW> (terminal width) means your expression is evaluated
236	evaluated again when the terminal is resized.	378	again when the terminal is resized.
237		379
238	=over 4	380	=over 4
239		381
240	=item TX	382	=item TX
241		383
…		…
290	C<$seconds> seconds.	432	C<$seconds> seconds.
291		433
292	Example: load some image and rotate it according to the time of day (as if it were	434	Example: load some image and rotate it according to the time of day (as if it were
293	the hour pointer of a clock). Update this image every minute.	435	the hour pointer of a clock). Update this image every minute.
294		436
295	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"	437	again 60; rotate 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
296		438
297	=item counter $seconds	439	=item counter $seconds
298		440
299	Like C<again>, but also returns an increasing counter value, starting at	441	Like C<again>, but also returns an increasing counter value, starting at
300	0, which might be useful for some simple animation effects.	442	0, which might be useful for some simple animation effects.
…		…
312	$self->{counter} + 0	454	$self->{counter} + 0
313	}	455	}
314		456
315	=back	457	=back
316		458
317	=head2 TILING MODES	459	=head2 SHAPE CHANGING OPERATORS
318		460
319	The following operators modify the tiling mode of an image, that is, the	461	The following operators modify the shape, size or position of the image.
320	way that pixels outside the image area are painted when the image is used.
321		462
322	=over 4	463	=over 4
323
324	=item tile $img
325
326	Tiles the whole plane with the image and returns this new image - or in
327	other words, it returns a copy of the image in plane tiling mode.
328
329	Example: load an image and tile it over the background, without
330	resizing. The C<tile> call is superfluous because C<load> already defaults
331	to tiling mode.
332
333	tile load "mybg.png"
334
335	=item mirror $img
336
337	Similar to tile, but reflects the image each time it uses a new copy, so
338	that top edges always touch top edges, right edges always touch right
339	edges and so on (with normal tiling, left edges always touch right edges
340	and top always touch bottom edges).
341
342	Example: load an image and mirror it over the background, avoiding sharp
343	edges at the image borders at the expense of mirroring the image itself
344
345	mirror load "mybg.png"
346
347	=item pad $img
348
349	Takes an image and modifies it so that all pixels outside the image area
350	become transparent. This mode is most useful when you want to place an
351	image over another image or the background colour while leaving all
352	background pixels outside the image unchanged.
353
354	Example: load an image and display it in the upper left corner. The rest
355	of the space is left "empty" (transparent or wahtever your compisotr does
356	in alpha mode, else background colour).
357
358	pad load "mybg.png"
359
360	=item extend $img
361
362	Extends the image over the whole plane, using the closest pixel in the
363	area outside the image. This mode is mostly useful when you more complex
364	filtering operations and want the pixels outside the image to have the
365	same values as the pixels near the edge.
366
367	Example: just for curiosity, how does this pixel extension stuff work?
368
369	extend move 50, 50, load "mybg.png"
370
371	=cut
372
373	sub pad($) {
374	my $img = $_[0]->clone;
375	$img->repeat_mode (urxvt::RepeatNone);
376	$img
377	}
378
379	sub tile($) {
380	my $img = $_[0]->clone;
381	$img->repeat_mode (urxvt::RepeatNormal);
382	$img
383	}
384
385	sub mirror($) {
386	my $img = $_[0]->clone;
387	$img->repeat_mode (urxvt::RepeatReflect);
388	$img
389	}
390
391	sub extend($) {
392	my $img = $_[0]->clone;
393	$img->repeat_mode (urxvt::RepeatPad);
394	$img
395	}
396
397	=back
398
399	=head2 PIXEL OPERATORS
400
401	The following operators modify the image pixels in various ways.
402
403	=over 4
404
405	=item clone $img
406
407	Returns an exact copy of the image.
408
409	=cut
410
411	sub clone($) {
412	$_[0]->clone
413	}
414		464
415	=item clip $img	465	=item clip $img
416		466
417	=item clip $width, $height, $img	467	=item clip $width, $height, $img
418		468
…		…
442	$img->sub_rect ($_[0], $_[1], $w, $h)	492	$img->sub_rect ($_[0], $_[1], $w, $h)
443	}	493	}
444		494
445	=item scale $img	495	=item scale $img
446		496
447	=item scale $size_percent, $img	497	=item scale $size_factor, $img
448		498
449	=item scale $width_percent, $height_percent, $img	499	=item scale $width_factor, $height_factor, $img
450		500
451	Scales the image by the given percentages in horizontal	501	Scales the image by the given factors in horizontal
452	(C<$width_percent>) and vertical (C<$height_percent>) direction.	502	(C<$width>) and vertical (C<$height>) direction.
453		503
454	If only one percentage is give, it is used for both directions.	504	If only one factor is give, it is used for both directions.
455		505
456	If no percentages are given, scales the image to the window size without	506	If no factors are given, scales the image to the window size without
457	keeping aspect.	507	keeping aspect.
458		508
459	=item resize $width, $height, $img	509	=item resize $width, $height, $img
460		510
461	Resizes the image to exactly C<$width> times C<$height> pixels.	511	Resizes the image to exactly C<$width> times C<$height> pixels.
462		512
463	=cut	513	=item fit $img
464		514
465	#TODO: maximise, maximise_fill?	515	=item fit $width, $height, $img
		516
		517	Fits the image into the given C<$width> and C<$height> without changing
		518	aspect, or the terminal size. That means it will be shrunk or grown until
		519	the whole image fits into the given area, possibly leaving borders.
		520
		521	=item cover $img
		522
		523	=item cover $width, $height, $img
		524
		525	Similar to C<fit>, but shrinks or grows until all of the area is covered
		526	by the image, so instead of potentially leaving borders, it will cut off
		527	image data that doesn't fit.
		528
		529	=cut
466		530
467	sub scale($;$;$) {	531	sub scale($;$;$) {
468	my $img = pop;	532	my $img = pop;
469		533
470	@_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01)	534	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
471	: @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01)	535	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
472	: $img->scale (TW, TH)	536	: $img->scale (TW, TH)
473	}	537	}
474		538
475	sub resize($$$) {	539	sub resize($$$) {
476	my $img = pop;	540	my $img = pop;
477	$img->scale ($_[0], $_[1])	541	$img->scale ($_[0], $_[1])
		542	}
		543
		544	sub fit($;$$) {
		545	my $img = pop;
		546	my $w = ($_[0] \|\| TW) / $img->w;
		547	my $h = ($_[1] \|\| TH) / $img->h;
		548	scale +(min $w, $h), $img
		549	}
		550
		551	sub cover($;$$) {
		552	my $img = pop;
		553	my $w = ($_[0] \|\| TW) / $img->w;
		554	my $h = ($_[1] \|\| TH) / $img->h;
		555	scale +(max $w, $h), $img
478	}	556	}
479		557
480	=item move $dx, $dy, $img	558	=item move $dx, $dy, $img
481		559
482	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in	560	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
483	the vertical.	561	the vertical.
484		562
485	Example: move the image right by 20 pixels and down by 30.	563	Example: move the image right by 20 pixels and down by 30.
486		564
487	move 20, 30, ...	565	move 20, 30, ...
		566
		567	=item align $xalign, $yalign, $img
		568
		569	Aligns the image according to a factor - C<0> means the image is moved to
		570	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		571	exactly centered and C<1> means it touches the right or bottom edge.
		572
		573	Example: remove any visible border around an image, center it vertically but move
		574	it to the right hand side.
		575
		576	align 1, 0.5, pad $img
		577
		578	=item center $img
		579
		580	=item center $width, $height, $img
		581
		582	Centers the image, i.e. the center of the image is moved to the center of
		583	the terminal window (or the box specified by C<$width> and C<$height> if
		584	given).
		585
		586	Example: load an image and center it.
		587
		588	center pad load "mybg.png"
488		589
489	=item rootalign $img	590	=item rootalign $img
490		591
491	Moves the image so that it appears glued to the screen as opposed to the	592	Moves the image so that it appears glued to the screen as opposed to the
492	window. This gives the illusion of a larger area behind the window. It is	593	window. This gives the illusion of a larger area behind the window. It is
…		…
498	rootalign mirror load "mybg.png"	599	rootalign mirror load "mybg.png"
499		600
500	Example: take the screen background and align it, giving the illusion of	601	Example: take the screen background and align it, giving the illusion of
501	transparency as long as the window isn't in front of other windows.	602	transparency as long as the window isn't in front of other windows.
502		603
503	rootalign root	604	rootalign root
504		605
505	=cut	606	=cut
506		607
507	sub move($$;$) {	608	sub move($$;$) {
508	my $img = pop->clone;	609	my $img = pop->clone;
509	$img->move ($_[0], $_[1]);	610	$img->move ($_[0], $_[1]);
510	$img	611	$img
511	}	612	}
512		613
		614	sub align($;$$) {
		615	my $img = pop;
		616
		617	move $_[0] * (TW - $img->w),
		618	$_[1] * (TH - $img->h),
		619	$img
		620	}
		621
		622	sub center($;$$) {
		623	my $img = pop;
		624	my $w = $_[0] \|\| TW;
		625	my $h = $_[1] \|\| TH;
		626
		627	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		628	}
		629
513	sub rootalign($) {	630	sub rootalign($) {
514	move -TX, -TY, $_[0]	631	move -TX, -TY, $_[0]
515	}	632	}
516		633
		634	=item rotate $center_x, $center_y, $degrees
		635
		636	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
		637	pointer at C<$center_x> and C<$center_y> (specified as factor of image
		638	width/height).
		639
		640	#TODO# new width, height, maybe more operators?
		641
		642	Example: rotate the image by 90 degrees
		643
		644	=cut
		645
		646	sub rotate($$$$) {
		647	my $img = pop;
		648	$img->rotate (
		649	$_[0] * $img->w,
		650	$_[1] * $img->h,
		651	$_[2] * (3.14159265 / 180),
		652	)
		653	}
		654
		655	=back
		656
		657	=head2 COLOUR MODIFICATIONS
		658
		659	The following operators change the pixels of the image.
		660
		661	=over 4
		662
517	=item contrast $factor, $img	663	=item contrast $factor, $img
518		664
519	=item contrast $r, $g, $b, $img	665	=item contrast $r, $g, $b, $img
520		666
521	=item contrast $r, $g, $b, $a, $img	667	=item contrast $r, $g, $b, $a, $img
522		668
523	Adjusts the I<contrast> of an image.	669	Adjusts the I<contrast> of an image.
524		670
525	#TODO#	671	The first form applies a single C<$factor> to red, green and blue, the
		672	second form applies separate factors to each colour channel, and the last
		673	form includes the alpha channel.
526		674
		675	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		676	contrast.
		677
		678	Due to limitations in the underlying XRender extension, lowering contrast
		679	also reduces brightness, while increasing contrast currently also
		680	increases brightness.
		681
527	=item brightness $factor, $img	682	=item brightness $bias, $img
528		683
529	=item brightness $r, $g, $b, $img	684	=item brightness $r, $g, $b, $img
530		685
531	=item brightness $r, $g, $b, $a, $img	686	=item brightness $r, $g, $b, $a, $img
532		687
533	Adjusts the brightness of an image.	688	Adjusts the brightness of an image.
534		689
		690	The first form applies a single C<$bias> to red, green and blue, the
		691	second form applies separate biases to each colour channel, and the last
		692	form includes the alpha channel.
		693
		694	Values less than 0 reduce brightness, while values larger than 0 increase
		695	it. Useful range is from -1 to 1 - the former results in a black, the
		696	latter in a white picture.
		697
		698	Due to idiosyncrasies in the underlying XRender extension, biases less
		699	than zero can be I<very> slow.
		700
535	=cut	701	=cut
536		702
537	sub contrast($$;$$;$) {	703	sub contrast($$;$$;$) {
538	my $img = pop;	704	my $img = pop;
539	my ($r, $g, $b, $a) = @_;	705	my ($r, $g, $b, $a) = @_;
540		706
541	($g, $b) = ($r, $r) if @_ < 4;	707	($g, $b) = ($r, $r) if @_ < 3;
542	$a = 1 if @_ < 5;	708	$a = 1 if @_ < 4;
543		709
544	$img = $img->clone;	710	$img = $img->clone;
545	$img->contrast ($r, $g, $b, $a);	711	$img->contrast ($r, $g, $b, $a);
546	$img	712	$img
547	}	713	}
548		714
549	sub brightness($$;$$;$) {	715	sub brightness($$;$$;$) {
550	my $img = pop;	716	my $img = pop;
551	my ($r, $g, $b, $a) = @_;	717	my ($r, $g, $b, $a) = @_;
552		718
553	($g, $b) = ($r, $r) if @_ < 4;	719	($g, $b) = ($r, $r) if @_ < 3;
554	$a = 1 if @_ < 5;	720	$a = 1 if @_ < 4;
555		721
556	$img = $img->clone;	722	$img = $img->clone;
557	$img->brightness ($r, $g, $b, $a);	723	$img->brightness ($r, $g, $b, $a);
558	$img	724	$img
559	}	725	}
…		…
563	=item blur $radius_horz, $radius_vert, $img	729	=item blur $radius_horz, $radius_vert, $img
564		730
565	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii	731	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
566	can also be specified separately.	732	can also be specified separately.
567		733
		734	Blurring is often I<very> slow, at least compared or other
		735	operators. Larger blur radii are slower than smaller ones, too, so if you
		736	don't want to freeze your screen for long times, start experimenting with
		737	low values for radius (<5).
		738
568	=cut	739	=cut
569		740
570	sub blur($$;$) {	741	sub blur($$;$) {
571	my $img = pop;	742	my $img = pop;
572	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	743	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
573	}	744	}
574		745
575	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees	746	=back
576		747
577	Rotates the image by C<$degrees> degrees, counter-clockwise, around the	748	=head2 OTHER STUFF
578	pointer at C<$center_x> and C<$center_y> (specified as percentage of image
579	width/height), generating a new image with width C<$new_width> and height
580	C<$new_height>.
581		749
582	#TODO# new width, height, maybe more operators?	750	Anything that didn't fit any of the other categories, even after appliyng
		751	force and closing our eyes.
583		752
584	Example: rotate the image by 90 degrees	753	=over 4
585		754
586	=cut	755	=item once { ... }
587		756
588	sub rotate($$$$$$) {	757	This function takes a code block as argument, that is, one or more
589	my $img = pop;	758	statements enclosed by braces.
590	$img->rotate (	759
591	$_[0],	760	The trick is that this code block is only evaluated once - future calls
592	$_[1],	761	will simply return the original image (yes, it should only be used with
593	$_[2] * $img->w * .01,	762	images).
594	$_[3] * $img->h * .01,	763
595	$_[4] * (3.14159265 / 180),	764	This can be extremely useful to avoid redoign the same slow operations
596	)	765	again and again- for example, if your background expression takes the root
		766	background, blurs it and then root-aligns it it would have to blur the
		767	root background on every window move or resize.
		768
		769	Putting the blur into a C<once> block will make sure the blur is only done
		770	once:
		771
		772	rootlign once { blur 10, root }
		773
		774	This leaves the question of how to force reevaluation of the block, in
		775	case the root background changes: Right now, all once blocks forget that
		776	they ahve been executed before each time the root background changes (if
		777	the expression is sensitive to that) or when C<once_again> is called.
		778
		779	=item once_again
		780
		781	Resets all C<once> block as if they had never been called, i.e. on the
		782	next call they will be reevaluated again.
		783
		784	=cut
		785
		786	sub once(&) {
		787	$_ONCE_CACHE{$_[0]+0} \|\|= $_[0]()
		788	}
		789
		790	sub once_again() {
		791	%_ONCE_CACHE = ();
597	}	792	}
598		793
599	=back	794	=back
600		795
601	=cut	796	=cut
…		…
644		839
645	# evaluate user expression	840	# evaluate user expression
646		841
647	my $img = eval { $self->{expr}->() };	842	my $img = eval { $self->{expr}->() };
648	warn $@ if $@;#d#	843	warn $@ if $@;#d#
649	die if !UNIVERSAL::isa $img, "urxvt::img";	844	die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";
650		845
651	$state->{size_sensitive} = 1	846	$state->{size_sensitive} = 1
652	if $img->repeat_mode != urxvt::RepeatNormal;	847	if $img->repeat_mode != urxvt::RepeatNormal;
653		848
654	# if the expression is sensitive to external events, prepare reevaluation then	849	# if the expression is sensitive to external events, prepare reevaluation then
…		…
704	}	899	}
705		900
706	sub on_start {	901	sub on_start {
707	my ($self) = @_;	902	my ($self) = @_;
708		903
709	my $expr = $self->x_resource ("background.expr")	904	my $expr = $self->x_resource ("%.expr")
710	or return;	905	or return;
711		906
		907	$self->has_render
		908	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		909
712	$self->set_expr (parse_expr $expr);	910	$self->set_expr (parse_expr $expr);
713	$self->{border} = $self->x_resource_boolean ("background.border");	911	$self->{border} = $self->x_resource_boolean ("%.border");
		912
		913	$MIN_INTERVAL = $self->x_resource ("%.interval");
714		914
715	()	915	()
716	}	916	}
717		917

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.38 by root, Fri Jun 8 21:48:07 2012 UTC vs. Revision 1.53 by root, Tue Jun 12 18:25:57 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.38 by root, Fri Jun 8 21:48:07 2012 UTC vs.
Revision 1.53 by root, Tue Jun 12 18:25:57 2012 UTC