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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.36 by root, Fri Jun 8 20:23:09 2012 UTC vs.
Revision 1.54 by root, Thu Jun 14 16:22:20 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;
…		…
69	return scale load "$HOME/weekday.png";	71	return scale load "$HOME/weekday.png";
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 is 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
…		…
179	=item load $path	229	=item load $path
180		230
181	Loads the image at the given C<$path>. The image is set to plane tiling	231	Loads the image at the given C<$path>. The image is set to plane tiling
182	mode.	232	mode.
183		233
184	Loaded images will be cached for one cycle.	234	Loaded images will be cached for one cycle, and shared between temrinals
		235	running in the same process (e.g. in C<urxvtd>).
185		236
		237	=item load_uc $path
		238
		239	Load uncached - same as load, but does not cache the image. This function
		240	is most useufl if you want to optimise a background expression in some
		241	way.
		242
186	=cut	243	=cut
		244
		245	sub load_uc($) {
		246	my ($path) = @_;
		247
		248	$_IMG_CACHE{$path} \|\| do {
		249	my $img = $self->new_img_from_file ($path);
		250	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		251	$img
		252	}
		253	}
187		254
188	sub load($) {	255	sub load($) {
189	my ($path) = @_;	256	my ($path) = @_;
190		257
191	$new->{load}{$path} = $old->{load}{$path} \|\| $self->new_img_from_file ($path);	258	$new->{load}{$path} = $old->{load}{$path} \|\| load_uc $path;
192	}	259	}
193		260
194	=item root	261	=item root
195		262
196	Returns the root window pixmap, that is, hopefully, the background image	263	Returns the root window pixmap, that is, hopefully, the background image
…		…
201		268
202	=cut	269	=cut
203		270
204	sub root() {	271	sub root() {
205	$new->{rootpmap_sensitive} = 1;	272	$new->{rootpmap_sensitive} = 1;
206	die "root op not supported, exg, we need you";	273	$self->new_img_from_root
207	}	274	}
208		275
209	=item solid $colour	276	=item solid $colour
210		277
211	=item solid $width, $height, $colour	278	=item solid $width, $height, $colour
212		279
213	Creates a new image and completely fills it with the given colour. The	280	Creates a new image and completely fills it with the given colour. The
214	image is set to tiling mode.	281	image is set to tiling mode.
215		282
216	If <$width> and C<$height> are omitted, it creates a 1x1 image, which is	283	If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
217	useful for solid backgrounds or for use in filtering effects.	284	useful for solid backgrounds or for use in filtering effects.
218		285
219	=cut	286	=cut
220		287
221	sub solid($$;$) {	288	sub solid($;$$) {
222	my $colour = pop;	289	my $colour = pop;
223		290
224	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	291	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);
225	$img->fill ($colour);	292	$img->fill ($colour);
226	$img	293	$img
227	}	294	}
228		295
		296	=item clone $img
		297
		298	Returns an exact copy of the image. This is useful if you want to have
		299	multiple copies of the same image to apply different effects to.
		300
		301	=cut
		302
		303	sub clone($) {
		304	$_[0]->clone
		305	}
		306
		307	=head2 TILING MODES
		308
		309	The following operators modify the tiling mode of an image, that is, the
		310	way that pixels outside the image area are painted when the image is used.
		311
		312	=over 4
		313
		314	=item tile $img
		315
		316	Tiles the whole plane with the image and returns this new image - or in
		317	other words, it returns a copy of the image in plane tiling mode.
		318
		319	Example: load an image and tile it over the background, without
		320	resizing. The C<tile> call is superfluous because C<load> already defaults
		321	to tiling mode.
		322
		323	tile load "mybg.png"
		324
		325	=item mirror $img
		326
		327	Similar to tile, but reflects the image each time it uses a new copy, so
		328	that top edges always touch top edges, right edges always touch right
		329	edges and so on (with normal tiling, left edges always touch right edges
		330	and top always touch bottom edges).
		331
		332	Example: load an image and mirror it over the background, avoiding sharp
		333	edges at the image borders at the expense of mirroring the image itself
		334
		335	mirror load "mybg.png"
		336
		337	=item pad $img
		338
		339	Takes an image and modifies it so that all pixels outside the image area
		340	become transparent. This mode is most useful when you want to place an
		341	image over another image or the background colour while leaving all
		342	background pixels outside the image unchanged.
		343
		344	Example: load an image and display it in the upper left corner. The rest
		345	of the space is left "empty" (transparent or whatever your compositor does
		346	in alpha mode, else background colour).
		347
		348	pad load "mybg.png"
		349
		350	=item extend $img
		351
		352	Extends the image over the whole plane, using the closest pixel in the
		353	area outside the image. This mode is mostly useful when you use more complex
		354	filtering operations and want the pixels outside the image to have the
		355	same values as the pixels near the edge.
		356
		357	Example: just for curiosity, how does this pixel extension stuff work?
		358
		359	extend move 50, 50, load "mybg.png"
		360
		361	=cut
		362
		363	sub pad($) {
		364	my $img = $_[0]->clone;
		365	$img->repeat_mode (urxvt::RepeatNone);
		366	$img
		367	}
		368
		369	sub tile($) {
		370	my $img = $_[0]->clone;
		371	$img->repeat_mode (urxvt::RepeatNormal);
		372	$img
		373	}
		374
		375	sub mirror($) {
		376	my $img = $_[0]->clone;
		377	$img->repeat_mode (urxvt::RepeatReflect);
		378	$img
		379	}
		380
		381	sub extend($) {
		382	my $img = $_[0]->clone;
		383	$img->repeat_mode (urxvt::RepeatPad);
		384	$img
		385	}
		386
229	=back	387	=back
230		388
231	=head2 VARIABLES	389	=head2 VARIABLE VALUES
232		390
233	The following functions provide variable data such as the terminal	391	The following functions provide variable data such as the terminal window
		392	dimensions. They are not (Perl-) variables, they just return stuff that
234	window dimensions. Most of them make your expression sensitive to some	393	varies. Most of them make your expression sensitive to some events, for
235	events, for example using C<TW> (terminal width) means your expression is	394	example using C<TW> (terminal width) means your expression is evaluated
236	evaluated again when the terminal is resized.	395	again when the terminal is resized.
237		396
238	=over 4	397	=over 4
239		398
240	=item TX	399	=item TX
241		400
…		…
290	C<$seconds> seconds.	449	C<$seconds> seconds.
291		450
292	Example: load some image and rotate it according to the time of day (as if it were	451	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.	452	the hour pointer of a clock). Update this image every minute.
294		453
295	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"	454	again 60; rotate 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
296		455
297	=item counter $seconds	456	=item counter $seconds
298		457
299	Like C<again>, but also returns an increasing counter value, starting at	458	Like C<again>, but also returns an increasing counter value, starting at
300	0, which might be useful for some simple animation effects.	459	0, which might be useful for some simple animation effects.
…		…
312	$self->{counter} + 0	471	$self->{counter} + 0
313	}	472	}
314		473
315	=back	474	=back
316		475
317	=head2 TILING MODES	476	=head2 SHAPE CHANGING OPERATORS
318		477
319	The following operators modify the tiling mode of an image, that is, the	478	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		479
322	=over 4	480	=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		481
415	=item clip $img	482	=item clip $img
416		483
417	=item clip $width, $height, $img	484	=item clip $width, $height, $img
418		485
…		…
442	$img->sub_rect ($_[0], $_[1], $w, $h)	509	$img->sub_rect ($_[0], $_[1], $w, $h)
443	}	510	}
444		511
445	=item scale $img	512	=item scale $img
446		513
447	=item scale $size_percent, $img	514	=item scale $size_factor, $img
448		515
449	=item scale $width_percent, $height_percent, $img	516	=item scale $width_factor, $height_factor, $img
450		517
451	Scales the image by the given percentages in horizontal	518	Scales the image by the given factors in horizontal
452	(C<$width_percent>) and vertical (C<$height_percent>) direction.	519	(C<$width>) and vertical (C<$height>) direction.
453		520
454	If only one percentage is give, it is used for both directions.	521	If only one factor is give, it is used for both directions.
455		522
456	If no percentages are given, scales the image to the window size without	523	If no factors are given, scales the image to the window size without
457	keeping aspect.	524	keeping aspect.
458		525
459	=item resize $width, $height, $img	526	=item resize $width, $height, $img
460		527
461	Resizes the image to exactly C<$width> times C<$height> pixels.	528	Resizes the image to exactly C<$width> times C<$height> pixels.
462		529
463	=cut	530	=item fit $img
464		531
465	#TODO: maximise, maximise_fill?	532	=item fit $width, $height, $img
		533
		534	Fits the image into the given C<$width> and C<$height> without changing
		535	aspect, or the terminal size. That means it will be shrunk or grown until
		536	the whole image fits into the given area, possibly leaving borders.
		537
		538	=item cover $img
		539
		540	=item cover $width, $height, $img
		541
		542	Similar to C<fit>, but shrinks or grows until all of the area is covered
		543	by the image, so instead of potentially leaving borders, it will cut off
		544	image data that doesn't fit.
		545
		546	=cut
466		547
467	sub scale($;$;$) {	548	sub scale($;$;$) {
468	my $img = pop;	549	my $img = pop;
469		550
470	@_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01)	551	@_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
471	: @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01)	552	: @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
472	: $img->scale (TW, TH)	553	: $img->scale (TW, TH)
473	}	554	}
474		555
475	sub resize($$$) {	556	sub resize($$$) {
476	my $img = pop;	557	my $img = pop;
477	$img->scale ($_[0], $_[1])	558	$img->scale ($_[0], $_[1])
		559	}
		560
		561	sub fit($;$$) {
		562	my $img = pop;
		563	my $w = ($_[0] \|\| TW) / $img->w;
		564	my $h = ($_[1] \|\| TH) / $img->h;
		565	scale +(min $w, $h), $img
		566	}
		567
		568	sub cover($;$$) {
		569	my $img = pop;
		570	my $w = ($_[0] \|\| TW) / $img->w;
		571	my $h = ($_[1] \|\| TH) / $img->h;
		572	scale +(max $w, $h), $img
478	}	573	}
479		574
480	=item move $dx, $dy, $img	575	=item move $dx, $dy, $img
481		576
482	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in	577	Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
483	the vertical.	578	the vertical.
484		579
485	Example: move the image right by 20 pixels and down by 30.	580	Example: move the image right by 20 pixels and down by 30.
486		581
487	move 20, 30, ...	582	move 20, 30, ...
		583
		584	=item align $xalign, $yalign, $img
		585
		586	Aligns the image according to a factor - C<0> means the image is moved to
		587	the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
		588	exactly centered and C<1> means it touches the right or bottom edge.
		589
		590	Example: remove any visible border around an image, center it vertically but move
		591	it to the right hand side.
		592
		593	align 1, 0.5, pad $img
		594
		595	=item center $img
		596
		597	=item center $width, $height, $img
		598
		599	Centers the image, i.e. the center of the image is moved to the center of
		600	the terminal window (or the box specified by C<$width> and C<$height> if
		601	given).
		602
		603	Example: load an image and center it.
		604
		605	center pad load "mybg.png"
488		606
489	=item rootalign $img	607	=item rootalign $img
490		608
491	Moves the image so that it appears glued to the screen as opposed to the	609	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	610	window. This gives the illusion of a larger area behind the window. It is
…		…
498	rootalign mirror load "mybg.png"	616	rootalign mirror load "mybg.png"
499		617
500	Example: take the screen background and align it, giving the illusion of	618	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.	619	transparency as long as the window isn't in front of other windows.
502		620
503	rootalign root	621	rootalign root
504		622
505	=cut	623	=cut
506		624
507	sub move($$;$) {	625	sub move($$;$) {
508	my $img = pop->clone;	626	my $img = pop->clone;
509	$img->move ($_[0], $_[1]);	627	$img->move ($_[0], $_[1]);
510	$img	628	$img
511	}	629	}
512		630
		631	sub align($;$$) {
		632	my $img = pop;
		633
		634	move $_[0] * (TW - $img->w),
		635	$_[1] * (TH - $img->h),
		636	$img
		637	}
		638
		639	sub center($;$$) {
		640	my $img = pop;
		641	my $w = $_[0] \|\| TW;
		642	my $h = $_[1] \|\| TH;
		643
		644	move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
		645	}
		646
513	sub rootalign($) {	647	sub rootalign($) {
514	move -TX, -TY, $_[0]	648	move -TX, -TY, $_[0]
515	}	649	}
516		650
		651	=item rotate $center_x, $center_y, $degrees
		652
		653	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
		654	pointer at C<$center_x> and C<$center_y> (specified as factor of image
		655	width/height).
		656
		657	#TODO# new width, height, maybe more operators?
		658
		659	Example: rotate the image by 90 degrees
		660
		661	=cut
		662
		663	sub rotate($$$$) {
		664	my $img = pop;
		665	$img->rotate (
		666	$_[0] * $img->w,
		667	$_[1] * $img->h,
		668	$_[2] * (3.14159265 / 180),
		669	)
		670	}
		671
		672	=back
		673
		674	=head2 COLOUR MODIFICATIONS
		675
		676	The following operators change the pixels of the image.
		677
		678	=over 4
		679
517	=item contrast $factor, $img	680	=item contrast $factor, $img
518		681
519	=item contrast $r, $g, $b, $img	682	=item contrast $r, $g, $b, $img
520		683
521	=item contrast $r, $g, $b, $a, $img	684	=item contrast $r, $g, $b, $a, $img
522		685
523	Adjusts the I<contrast> of an image.	686	Adjusts the I<contrast> of an image.
524		687
		688	The first form applies a single C<$factor> to red, green and blue, the
		689	second form applies separate factors to each colour channel, and the last
		690	form includes the alpha channel.
		691
		692	Values from 0 to 1 lower the contrast, values higher than 1 increase the
		693	contrast.
		694
		695	Due to limitations in the underlying XRender extension, lowering contrast
		696	also reduces brightness, while increasing contrast currently also
		697	increases brightness.
		698
525	=item brightness $factor, $img	699	=item brightness $bias, $img
526		700
527	=item brightness $r, $g, $b, $img	701	=item brightness $r, $g, $b, $img
528		702
529	=item brightness $r, $g, $b, $a, $img	703	=item brightness $r, $g, $b, $a, $img
530		704
		705	Adjusts the brightness of an image.
		706
		707	The first form applies a single C<$bias> to red, green and blue, the
		708	second form applies separate biases to each colour channel, and the last
		709	form includes the alpha channel.
		710
		711	Values less than 0 reduce brightness, while values larger than 0 increase
		712	it. Useful range is from -1 to 1 - the former results in a black, the
		713	latter in a white picture.
		714
		715	Due to idiosyncrasies in the underlying XRender extension, biases less
		716	than zero can be I<very> slow.
		717
531	=cut	718	=cut
532		719
533	sub contrast($$;$$;$) {	720	sub contrast($$;$$;$) {
534	my $img = pop;	721	my $img = pop;
535	my ($r, $g, $b, $a) = @_;	722	my ($r, $g, $b, $a) = @_;
536		723
537	($g, $b) = ($r, $r) if @_ < 4;	724	($g, $b) = ($r, $r) if @_ < 3;
538	$a = 1 if @_ < 5;	725	$a = 1 if @_ < 4;
539		726
540	$img = $img->clone;	727	$img = $img->clone;
541	# $img->contrast ($r, $g, $b, $a);	728	$img->contrast ($r, $g, $b, $a);
542	$img	729	$img
543	}	730	}
544		731
545	sub brightness($$;$$;$) {	732	sub brightness($$;$$;$) {
546	my $img = pop;	733	my $img = pop;
547	my ($r, $g, $b, $a) = @_;	734	my ($r, $g, $b, $a) = @_;
548		735
549	($g, $b) = ($r, $r) if @_ < 4;	736	($g, $b) = ($r, $r) if @_ < 3;
550	$a = 1 if @_ < 5;	737	$a = 1 if @_ < 4;
551		738
552	$img = $img->clone;	739	$img = $img->clone;
553	$img->brightness ($r, $g, $b, $a);	740	$img->brightness ($r, $g, $b, $a);
554	$img	741	$img
555	}	742	}
556		743
		744	=item blur $radius, $img
		745
		746	=item blur $radius_horz, $radius_vert, $img
		747
		748	Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
		749	can also be specified separately.
		750
		751	Blurring is often I<very> slow, at least compared or other
		752	operators. Larger blur radii are slower than smaller ones, too, so if you
		753	don't want to freeze your screen for long times, start experimenting with
		754	low values for radius (<5).
		755
		756	=cut
		757
557	sub blur($$;$) {	758	sub blur($$;$) {
558	my $img = pop;	759	my $img = pop;
559	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	760	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
560	}	761	}
561		762
562	sub rotate($$$$$$) {	763	=back
563	my $img = pop;	764
564	$img->rotate (	765	=head2 OTHER STUFF
565	$_[0],	766
566	$_[1],	767	Anything that didn't fit any of the other categories, even after appliyng
567	$_[2] * $img->w * .01,	768	force and closing our eyes.
568	$_[3] * $img->h * .01,	769
569	$_[4] * (3.14159265 / 180),	770	=over 4
570	)	771
		772	=item once { ... }
		773
		774	This function takes a code block as argument, that is, one or more
		775	statements enclosed by braces.
		776
		777	The trick is that this code block is only evaluated once - future calls
		778	will simply return the original image (yes, it should only be used with
		779	images).
		780
		781	This can be extremely useful to avoid redoign the same slow operations
		782	again and again- for example, if your background expression takes the root
		783	background, blurs it and then root-aligns it it would have to blur the
		784	root background on every window move or resize.
		785
		786	Putting the blur into a C<once> block will make sure the blur is only done
		787	once:
		788
		789	rootlign once { blur 10, root }
		790
		791	This leaves the question of how to force reevaluation of the block, in
		792	case the root background changes: Right now, all once blocks forget that
		793	they ahve been executed before each time the root background changes (if
		794	the expression is sensitive to that) or when C<once_again> is called.
		795
		796	=item once_again
		797
		798	Resets all C<once> block as if they had never been called, i.e. on the
		799	next call they will be reevaluated again.
		800
		801	=cut
		802
		803	sub once(&) {
		804	$_ONCE_CACHE{$_[0]+0} \|\|= $_[0]()
		805	}
		806
		807	sub once_again() {
		808	%_ONCE_CACHE = ();
571	}	809	}
572		810
573	=back	811	=back
574		812
575	=cut	813	=cut
…		…
618		856
619	# evaluate user expression	857	# evaluate user expression
620		858
621	my $img = eval { $self->{expr}->() };	859	my $img = eval { $self->{expr}->() };
622	warn $@ if $@;#d#	860	warn $@ if $@;#d#
623	die if !UNIVERSAL::isa $img, "urxvt::img";	861	die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";
624		862
625	$state->{size_sensitive} = 1	863	$state->{size_sensitive} = 1
626	if $img->repeat_mode != urxvt::RepeatNormal;	864	if $img->repeat_mode != urxvt::RepeatNormal;
627		865
628	# if the expression is sensitive to external events, prepare reevaluation then	866	# if the expression is sensitive to external events, prepare reevaluation then
…		…
678	}	916	}
679		917
680	sub on_start {	918	sub on_start {
681	my ($self) = @_;	919	my ($self) = @_;
682		920
683	my $expr = $self->x_resource ("background.expr")	921	my $expr = $self->x_resource ("%.expr")
684	or return;	922	or return;
685		923
		924	$self->has_render
		925	or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
		926
686	$self->set_expr (parse_expr $expr);	927	$self->set_expr (parse_expr $expr);
687	$self->{border} = $self->x_resource_boolean ("background.border");	928	$self->{border} = $self->x_resource_boolean ("%.border");
		929
		930	$MIN_INTERVAL = $self->x_resource ("%.interval");
688		931
689	()	932	()
690	}	933	}
691		934

Diff Legend

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

Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.36 by root, Fri Jun 8 20:23:09 2012 UTC vs. Revision 1.54 by root, Thu Jun 14 16:22:20 2012 UTC

Diff Legend

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.36 by root, Fri Jun 8 20:23:09 2012 UTC vs.
Revision 1.54 by root, Thu Jun 14 16:22:20 2012 UTC