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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.39 by root, Fri Jun 8 22:19:03 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;
…		…
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	Other effects than scalign are also readily available, for exmaple, you can	120	Other effects than scaling are also readily available, for example, you can
118	tile the image to fill the whole window, instead of resizing it:	121	tile the image to fill the whole window, instead of resizing it:
119		122
120	tile load "$HOME/mypic.png"	123	tile load "$HOME/mypic.png"
121		124
122	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator	125	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator
…		…
133	It first takes a snapshot of the screen background image, and then	136	It first takes a snapshot of the screen background image, and then
134	moves it to the upper left corner of the screen - the result is	137	moves it to the upper left corner of the screen - the result is
135	pseudo-transparency, as the image seems to be static while the window is	138	pseudo-transparency, as the image seems to be static while the window is
136	moved around.	139	moved around.
137		140
138	=head3 CYCLES AND CACHING	141	=head2 CYCLES AND CACHING
139		142
140	As has been mentioned before, the expression might be evaluated multiple	143	As has been mentioned before, the expression might be evaluated multiple
141	times. Each time the expression is reevaluated, a new cycle is said to	144	times. Each time the expression is reevaluated, a new cycle is said to
142	have begun. Many operators cache their results till the next cycle.	145	have begun. Many operators cache their results till the next cycle.
143		146
…		…
148	This only works for one cycle though, so as long as you load the same	151	This only works for one cycle though, so as long as you load the same
149	image every time, it will always be cached, but when you load a different	152	image every time, it will always be cached, but when you load a different
150	image, it will forget about the first one.	153	image, it will forget about the first one.
151		154
152	This allows you to either speed things up by keeping multiple images in	155	This allows you to either speed things up by keeping multiple images in
153	memory, or comserve memory by loading images more often.	156	memory, or conserve memory by loading images more often.
154		157
155	For example, you can keep two images in memory and use a random one like	158	For example, you can keep two images in memory and use a random one like
156	this:	159	this:
157		160
158	my $img1 = load "img1.png";	161	my $img1 = load "img1.png";
…		…
168		171
169	Here, a path is selected randomly, and load is only called for one image,	172	Here, a path is selected randomly, and load is only called for one image,
170	so keeps only one image in memory. If, on the next evaluation, luck	173	so keeps only one image in memory. If, on the next evaluation, luck
171	decides to use the other path, then it will have to load that image again.	174	decides to use the other path, then it will have to load that image again.
172		175
173	=head2 REFERENCE	176	=head1 REFERENCE
174		177
175	=head3 COMMAND LINE SWITCHES	178	=head2 COMMAND LINE SWITCHES
176		179
177	=over 4	180	=over 4
178		181
179	=item --background-expr perl-expression	182	=item --background-expr perl-expression
180		183
…		…
186	overwriting borders and any other areas, such as the scrollbar.	189	overwriting borders and any other areas, such as the scrollbar.
187		190
188	Specifying this flag changes the behaviour, so that the image only	191	Specifying this flag changes the behaviour, so that the image only
189	replaces the background of the character area.	192	replaces the background of the character area.
190		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
191	=back	203	=back
192		204
193	=cut	205	=cut
194		206
		207	our %_IMG_CACHE;
		208	our %_ONCE_CACHE;
195	our $HOME;	209	our $HOME;
196	our ($self, $old, $new);	210	our ($self, $old, $new);
197	our ($x, $y, $w, $h);	211	our ($x, $y, $w, $h);
198		212
199	# enforce at least this interval between updates	213	# enforce at least this interval between updates
200	our $MIN_INTERVAL = 1/100;	214	our $MIN_INTERVAL = 6/59.951;
201		215
202	{	216	{
203	package urxvt::bgdsl; # background language	217	package urxvt::bgdsl; # background language
		218
		219	use List::Util qw(min max sum shuffle);
204		220
205	=head2 PROVIDERS/GENERATORS	221	=head2 PROVIDERS/GENERATORS
206		222
207	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
208	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
…		…
235		251
236	=cut	252	=cut
237		253
238	sub root() {	254	sub root() {
239	$new->{rootpmap_sensitive} = 1;	255	$new->{rootpmap_sensitive} = 1;
240	die "root op not supported, exg, we need you";	256	$self->new_img_from_root
241	}	257	}
242		258
243	=item solid $colour	259	=item solid $colour
244		260
245	=item solid $width, $height, $colour	261	=item solid $width, $height, $colour
246		262
247	Creates a new image and completely fills it with the given colour. The	263	Creates a new image and completely fills it with the given colour. The
248	image is set to tiling mode.	264	image is set to tiling mode.
249		265
250	If <$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
251	useful for solid backgrounds or for use in filtering effects.	267	useful for solid backgrounds or for use in filtering effects.
252		268
253	=cut	269	=cut
254		270
255	sub solid($$;$) {	271	sub solid($;$$) {
256	my $colour = pop;	272	my $colour = pop;
257		273
258	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	274	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);
259	$img->fill ($colour);	275	$img->fill ($colour);
260	$img	276	$img
261	}	277	}
262		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	$img
		368	}
		369
263	=back	370	=back
264		371
265	=head2 VARIABLES	372	=head2 VARIABLE VALUES
266		373
267	The following functions provide variable data such as the terminal	374	The following functions provide variable data such as the terminal window
		375	dimensions. They are not (Perl-) variables, they just return stuff that
268	window dimensions. Most of them make your expression sensitive to some	376	varies. Most of them make your expression sensitive to some events, for
269	events, for example using C<TW> (terminal width) means your expression is	377	example using C<TW> (terminal width) means your expression is evaluated
270	evaluated again when the terminal is resized.	378	again when the terminal is resized.
271		379
272	=over 4	380	=over 4
273		381
274	=item TX	382	=item TX
275		383
…		…
324	C<$seconds> seconds.	432	C<$seconds> seconds.
325		433
326	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
327	the hour pointer of a clock). Update this image every minute.	435	the hour pointer of a clock). Update this image every minute.
328		436
329	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"
330		438
331	=item counter $seconds	439	=item counter $seconds
332		440
333	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
334	0, which might be useful for some simple animation effects.	442	0, which might be useful for some simple animation effects.
…		…
346	$self->{counter} + 0	454	$self->{counter} + 0
347	}	455	}
348		456
349	=back	457	=back
350		458
351	=head2 TILING MODES	459	=head2 SHAPE CHANGING OPERATORS
352		460
353	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.
354	way that pixels outside the image area are painted when the image is used.
355		462
356	=over 4	463	=over 4
357
358	=item tile $img
359
360	Tiles the whole plane with the image and returns this new image - or in
361	other words, it returns a copy of the image in plane tiling mode.
362
363	Example: load an image and tile it over the background, without
364	resizing. The C<tile> call is superfluous because C<load> already defaults
365	to tiling mode.
366
367	tile load "mybg.png"
368
369	=item mirror $img
370
371	Similar to tile, but reflects the image each time it uses a new copy, so
372	that top edges always touch top edges, right edges always touch right
373	edges and so on (with normal tiling, left edges always touch right edges
374	and top always touch bottom edges).
375
376	Example: load an image and mirror it over the background, avoiding sharp
377	edges at the image borders at the expense of mirroring the image itself
378
379	mirror load "mybg.png"
380
381	=item pad $img
382
383	Takes an image and modifies it so that all pixels outside the image area
384	become transparent. This mode is most useful when you want to place an
385	image over another image or the background colour while leaving all
386	background pixels outside the image unchanged.
387
388	Example: load an image and display it in the upper left corner. The rest
389	of the space is left "empty" (transparent or wahtever your compisotr does
390	in alpha mode, else background colour).
391
392	pad load "mybg.png"
393
394	=item extend $img
395
396	Extends the image over the whole plane, using the closest pixel in the
397	area outside the image. This mode is mostly useful when you more complex
398	filtering operations and want the pixels outside the image to have the
399	same values as the pixels near the edge.
400
401	Example: just for curiosity, how does this pixel extension stuff work?
402
403	extend move 50, 50, load "mybg.png"
404
405	=cut
406
407	sub pad($) {
408	my $img = $_[0]->clone;
409	$img->repeat_mode (urxvt::RepeatNone);
410	$img
411	}
412
413	sub tile($) {
414	my $img = $_[0]->clone;
415	$img->repeat_mode (urxvt::RepeatNormal);
416	$img
417	}
418
419	sub mirror($) {
420	my $img = $_[0]->clone;
421	$img->repeat_mode (urxvt::RepeatReflect);
422	$img
423	}
424
425	sub extend($) {
426	my $img = $_[0]->clone;
427	$img->repeat_mode (urxvt::RepeatPad);
428	$img
429	}
430
431	=back
432
433	=head2 PIXEL OPERATORS
434
435	The following operators modify the image pixels in various ways.
436
437	=over 4
438
439	=item clone $img
440
441	Returns an exact copy of the image.
442
443	=cut
444
445	sub clone($) {
446	$_[0]->clone
447	}
448		464
449	=item clip $img	465	=item clip $img
450		466
451	=item clip $width, $height, $img	467	=item clip $width, $height, $img
452		468
…		…
476	$img->sub_rect ($_[0], $_[1], $w, $h)	492	$img->sub_rect ($_[0], $_[1], $w, $h)
477	}	493	}
478		494
479	=item scale $img	495	=item scale $img
480		496
481	=item scale $size_percent, $img	497	=item scale $size_factor, $img
482		498
483	=item scale $width_percent, $height_percent, $img	499	=item scale $width_factor, $height_factor, $img
484		500
485	Scales the image by the given percentages in horizontal	501	Scales the image by the given factors in horizontal
486	(C<$width_percent>) and vertical (C<$height_percent>) direction.	502	(C<$width>) and vertical (C<$height>) direction.
487		503
488	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.
489		505
490	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
491	keeping aspect.	507	keeping aspect.
492		508
493	=item resize $width, $height, $img	509	=item resize $width, $height, $img
494		510
495	Resizes the image to exactly C<$width> times C<$height> pixels.	511	Resizes the image to exactly C<$width> times C<$height> pixels.
496		512
497	=cut	513	=item fit $img
498		514
499	#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, $img
		524
		525	Similar to C<fit>, but shrinks or grows until all of the area is covered
		526	by the image, so instead of potentially leaving borders, it will cut off
		527	image data that doesn't fit.
		528
		529	=cut
500		530
501	sub scale($;$;$) {	531	sub scale($;$;$) {
502	my $img = pop;	532	my $img = pop;
503		533
504	@_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01)	534	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
505	: @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01)	535	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
506	: $img->scale (TW, TH)	536	: $img->scale (TW, TH)
507	}	537	}
508		538
509	sub resize($$$) {	539	sub resize($$$) {
510	my $img = pop;	540	my $img = pop;
511	$img->scale ($_[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
512	}	556	}
513		557
514	=item move $dx, $dy, $img	558	=item move $dx, $dy, $img
515		559
516	Moves the image by C<$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
517	the vertical.	561	the vertical.
518		562
519	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.
520		564
521	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"
522		589
523	=item rootalign $img	590	=item rootalign $img
524		591
525	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
526	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
…		…
532	rootalign mirror load "mybg.png"	599	rootalign mirror load "mybg.png"
533		600
534	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
535	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.
536		603
537	rootalign root	604	rootalign root
538		605
539	=cut	606	=cut
540		607
541	sub move($$;$) {	608	sub move($$;$) {
542	my $img = pop->clone;	609	my $img = pop->clone;
543	$img->move ($_[0], $_[1]);	610	$img->move ($_[0], $_[1]);
544	$img	611	$img
545	}	612	}
546		613
		614	sub align($;$$) {
		615	my $img = pop;
		616
		617	move $_[0] * (TW - $img->w),
		618	$_[1] * (TH - $img->h),
		619	$img
		620	}
		621
		622	sub center($;$$) {
		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), $img
		628	}
		629
547	sub rootalign($) {	630	sub rootalign($) {
548	move -TX, -TY, $_[0]	631	move -TX, -TY, $_[0]
549	}	632	}
550		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
551	=item contrast $factor, $img	663	=item contrast $factor, $img
552		664
553	=item contrast $r, $g, $b, $img	665	=item contrast $r, $g, $b, $img
554		666
555	=item contrast $r, $g, $b, $a, $img	667	=item contrast $r, $g, $b, $a, $img
556		668
557	Adjusts the I<contrast> of an image.	669	Adjusts the I<contrast> of an image.
558		670
559	#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.
560		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
561	=item brightness $factor, $img	682	=item brightness $bias, $img
562		683
563	=item brightness $r, $g, $b, $img	684	=item brightness $r, $g, $b, $img
564		685
565	=item brightness $r, $g, $b, $a, $img	686	=item brightness $r, $g, $b, $a, $img
566		687
567	Adjusts the brightness of an image.	688	Adjusts the brightness of an image.
568		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
569	=cut	701	=cut
570		702
571	sub contrast($$;$$;$) {	703	sub contrast($$;$$;$) {
572	my $img = pop;	704	my $img = pop;
573	my ($r, $g, $b, $a) = @_;	705	my ($r, $g, $b, $a) = @_;
574		706
575	($g, $b) = ($r, $r) if @_ < 4;	707	($g, $b) = ($r, $r) if @_ < 3;
576	$a = 1 if @_ < 5;	708	$a = 1 if @_ < 4;
577		709
578	$img = $img->clone;	710	$img = $img->clone;
579	$img->contrast ($r, $g, $b, $a);	711	$img->contrast ($r, $g, $b, $a);
580	$img	712	$img
581	}	713	}
582		714
583	sub brightness($$;$$;$) {	715	sub brightness($$;$$;$) {
584	my $img = pop;	716	my $img = pop;
585	my ($r, $g, $b, $a) = @_;	717	my ($r, $g, $b, $a) = @_;
586		718
587	($g, $b) = ($r, $r) if @_ < 4;	719	($g, $b) = ($r, $r) if @_ < 3;
588	$a = 1 if @_ < 5;	720	$a = 1 if @_ < 4;
589		721
590	$img = $img->clone;	722	$img = $img->clone;
591	$img->brightness ($r, $g, $b, $a);	723	$img->brightness ($r, $g, $b, $a);
592	$img	724	$img
593	}	725	}
…		…
609	sub blur($$;$) {	741	sub blur($$;$) {
610	my $img = pop;	742	my $img = pop;
611	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	743	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
612	}	744	}
613		745
614	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees	746	=back
615		747
616	Rotates the image by C<$degrees> degrees, counter-clockwise, around the	748	=head2 OTHER STUFF
617	pointer at C<$center_x> and C<$center_y> (specified as percentage of image
618	width/height), generating a new image with width C<$new_width> and height
619	C<$new_height>.
620		749
621	#TODO# new width, height, maybe more operators?	750	Anything that didn't fit any of the other categories, even after appliyng
		751	force and closing our eyes.
622		752
623	Example: rotate the image by 90 degrees	753	=over 4
624		754
625	=cut	755	=item once { ... }
626		756
627	sub rotate($$$$$$) {	757	This function takes a code block as argument, that is, one or more
628	my $img = pop;	758	statements enclosed by braces.
629	$img->rotate (	759
630	$_[0],	760	The trick is that this code block is only evaluated once - future calls
631	$_[1],	761	will simply return the original image (yes, it should only be used with
632	$_[2] * $img->w * .01,	762	images).
633	$_[3] * $img->h * .01,	763
634	$_[4] * (3.14159265 / 180),	764	This can be extremely useful to avoid redoign the same slow operations
635	)	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 = ();
636	}	792	}
637		793
638	=back	794	=back
639		795
640	=cut	796	=cut
…		…
683		839
684	# evaluate user expression	840	# evaluate user expression
685		841
686	my $img = eval { $self->{expr}->() };	842	my $img = eval { $self->{expr}->() };
687	warn $@ if $@;#d#	843	warn $@ if $@;#d#
688	die if !UNIVERSAL::isa $img, "urxvt::img";	844	die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";
689		845
690	$state->{size_sensitive} = 1	846	$state->{size_sensitive} = 1
691	if $img->repeat_mode != urxvt::RepeatNormal;	847	if $img->repeat_mode != urxvt::RepeatNormal;
692		848
693	# if the expression is sensitive to external events, prepare reevaluation then	849	# if the expression is sensitive to external events, prepare reevaluation then
…		…
743	}	899	}
744		900
745	sub on_start {	901	sub on_start {
746	my ($self) = @_;	902	my ($self) = @_;
747		903
748	my $expr = $self->x_resource ("background.expr")	904	my $expr = $self->x_resource ("%.expr")
749	or return;	905	or return;
750		906
		907	$self->has_render
		908	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		909
751	$self->set_expr (parse_expr $expr);	910	$self->set_expr (parse_expr $expr);
752	$self->{border} = $self->x_resource_boolean ("background.border");	911	$self->{border} = $self->x_resource_boolean ("%.border");
		912
		913	$MIN_INTERVAL = $self->x_resource ("%.interval");
753		914
754	()	915	()
755	}	916	}
756		917

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.39 by root, Fri Jun 8 22:19:03 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 1.39 by root, Fri Jun 8 22:19:03 2012 UTC vs.
Revision 1.53 by root, Tue Jun 12 18:25:57 2012 UTC