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

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.50 by root, Sun Jun 10 17:31:53 2012 UTC vs.
Revision 1.74 by root, Sat Jul 14 08:42:54 2012 UTC

…		…
26	to be as simple as possible.	26	to be as simple as possible.
27		27
28	For example, to load an image and scale it to the window size, you would	28	For example, to load an image and scale it to the window size, you would
29	use:	29	use:
30		30
31	urxvt --background-expr 'scale load "/path/to/mybg.png"'	31	urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
32		32
33	Or specified as a X resource:	33	Or specified as a X resource:
34		34
35	URxvt.background-expr: scale load "/path/to/mybg.png"	35	URxvt.background-expr: scale keep { load "/path/to/mybg.png" }
36		36
37	=head1 THEORY OF OPERATION	37	=head1 THEORY OF OPERATION
38		38
39	At startup, just before the window is mapped for the first time, the	39	At startup, just before the window is mapped for the first time, the
40	expression is evaluated and must yield an image. The image is then	40	expression is evaluated and must yield an image. The image is then
…		…
53	If any of the parameters that the expression relies on changes (when the	53	If any of the parameters that the expression relies on changes (when the
54	window is moved or resized, its position or size changes; when the root	54	window is moved or resized, its position or size changes; when the root
55	pixmap is replaced by another one the root background changes; or when the	55	pixmap is replaced by another one the root background changes; or when the
56	timer elapses), then the expression will be evaluated again.	56	timer elapses), then the expression will be evaluated again.
57		57
58	For example, an expression such as C<scale load "$HOME/mybg.png"> scales the	58	For example, an expression such as C<scale keep { load "$HOME/mybg.png"
59	image to the window size, so it relies on the window size and will	59	}> scales the image to the window size, so it relies on the window size
60	be reevaluated each time it is changed, but not when it moves for	60	and will be reevaluated each time it is changed, but not when it moves for
61	example. That ensures that the picture always fills the terminal, even	61	example. That ensures that the picture always fills the terminal, even
62	after it's size changes.	62	after its size changes.
63		63
64	=head2 EXPRESSIONS	64	=head2 EXPRESSIONS
65		65
66	Expressions are normal Perl expressions, in fact, they are Perl blocks -	66	Expressions are normal Perl expressions, in fact, they are Perl blocks -
67	which means you could use multiple lines and statements:	67	which means you could use multiple lines and statements:
68		68
		69	scale keep {
69	again 3600;	70	again 3600;
70	if (localtime now)[6]) {	71	if (localtime now)[6]) {
71	return scale load "$HOME/weekday.png";	72	return load "$HOME/weekday.png";
72	} else {	73	} else {
73	return scale load "$HOME/sunday.png";	74	return load "$HOME/sunday.png";
		75	}
74	}	76	}
75		77
76	This expression gets evaluated once per hour. It will set F<sunday.png> as	78	This inner expression is evaluated once per hour (and whenever the
		79	terminal window is resized). It sets F<sunday.png> as background on
77	background on Sundays, and F<weekday.png> on all other days.	80	Sundays, and F<weekday.png> on all other days.
78		81
79	Fortunately, we expect that most expressions will be much simpler, with	82	Fortunately, we expect that most expressions will be much simpler, with
80	little Perl knowledge needed.	83	little Perl knowledge needed.
81		84
82	Basically, you always start with a function that "generates" an image	85	Basically, you always start with a function that "generates" an image
…		…
115	horizontal and vertical dimensions. For example, this halves the image	118	horizontal and vertical dimensions. For example, this halves the image
116	width and doubles the image height:	119	width and doubles the image height:
117		120
118	scale 0.5, 2, load "$HOME/mypic.png"	121	scale 0.5, 2, load "$HOME/mypic.png"
119		122
120	Other effects than scalign are also readily available, for exmaple, you can	123	IF you try out these expressions, you might suffer from some sluggishness,
121	tile the image to fill the whole window, instead of resizing it:	124	because each time the terminal is resized, it loads the PNG image again
		125	and scales it. Scaling is usually fast (and unavoidable), but loading the
		126	image can be quite time consuming. This is where C<keep> comes in handy:
122		127
		128	scale 0.5, 2, keep { load "$HOME/mypic.png" }
		129
		130	The C<keep> operator executes all the statements inside the braces only
		131	once, or when it thinks the outcome might change. In other cases it
		132	returns the last value computed by the brace block.
		133
		134	This means that the C<load> is only executed once, which makes it much
		135	faster, but also means that more memory is being used, because the loaded
		136	image must be kept in memory at all times. In this expression, the
		137	trade-off is likely worth it.
		138
		139	But back to effects: Other effects than scaling are also readily
		140	available, for example, you can tile the image to fill the whole window,
		141	instead of resizing it:
		142
123	tile load "$HOME/mypic.png"	143	tile keep { load "$HOME/mypic.png" }
124		144
125	In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator	145	In fact, images returned by C<load> are in C<tile> mode by default, so the
126	is kind of superfluous.	146	C<tile> operator is kind of superfluous.
127		147
128	Another common effect is to mirror the image, so that the same edges touch:	148	Another common effect is to mirror the image, so that the same edges
		149	touch:
129		150
130	mirror load "$HOME/mypic.png"	151	mirror keep { load "$HOME/mypic.png" }
131		152
132	This is also a typical background expression:	153	Another common background expression is:
133		154
134	rootalign root	155	rootalign root
135		156
136	It first takes a snapshot of the screen background image, and then	157	This one first takes a snapshot of the screen background image, and then
137	moves it to the upper left corner of the screen - the result is	158	moves it to the upper left corner of the screen (as opposed to the upper
138	pseudo-transparency, as the image seems to be static while the window is	159	left corner of the terminal window)- the result is pseudo-transparency:
139	moved around.	160	the image seems to be static while the window is moved around.
140		161
141	=head2 CYCLES AND CACHING	162	=head2 COLOUR SPECIFICATIONS
142		163
143	As has been mentioned before, the expression might be evaluated multiple	164	Whenever an operator expects a "colour", then this can be specified in one
144	times. Each time the expression is reevaluated, a new cycle is said to	165	of two ways: Either as string with an X11 colour specification, such as:
145	have begun. Many operators cache their results till the next cycle.
146		166
147	For example, the C<load> operator keeps a copy of the image. If it is	167	"red" # named colour
148	asked to load the same image on the next cycle it will not load it again,	168	"#f00" # simple rgb
149	but return the cached copy.	169	"[50]red" # red with 50% alpha
		170	"TekHVC:300/50/50" # anything goes
150		171
151	This only works for one cycle though, so as long as you load the same	172	OR as an array reference with one, three or four components:
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		173
155	This allows you to either speed things up by keeping multiple images in	174	[0.5] # 50% gray, 100% alpha
156	memory, or comserve memory by loading images more often.	175	[0.5, 0, 0] # dark red, no green or blur, 100% alpha
		176	[0.5, 0, 0, 0.7] # same with explicit 70% alpha
157		177
158	For example, you can keep two images in memory and use a random one like	178	=head2 CACHING AND SENSITIVITY
159	this:
160		179
161	my $img1 = load "img1.png";	180	Since some operations (such as C<load> and C<blur>) can take a long time,
162	my $img2 = load "img2.png";	181	caching results can be very important for a smooth operation. Caching can
163	(0.5 > rand) ? $img1 : $img2	182	also be useful to reduce memory usage, though, for example, when an image
		183	is cached by C<load>, it could be shared by multiple terminal windows
		184	running inside urxvtd.
164		185
165	Since both images are "loaded" every time the expression is evaluated,	186	=head3 C<keep { ... }> caching
166	they are always kept in memory. Contrast this version:
167		187
168	my $path1 = "img1.png";	188	The most important way to cache expensive operations is to use C<keep {
169	my $path2 = "img2.png";	189	... }>. The C<keep> operator takes a block of multiple statements enclosed
170	load ((0.5 > rand) ? $path1 : $path2)	190	by C<{}> and keeps the return value in memory.
171		191
172	Here, a path is selected randomly, and load is only called for one image,	192	An expression can be "sensitive" to various external events, such as
173	so keeps only one image in memory. If, on the next evaluation, luck	193	scaling or moving the window, root background changes and timers. Simply
174	decides to use the other path, then it will have to load that image again.	194	using an expression (such as C<scale> without parameters) that depends on
		195	certain changing values (called "variables"), or using those variables
		196	directly, will make an expression sensitive to these events - for example,
		197	using C<scale> or C<TW> will make the expression sensitive to the terminal
		198	size, and thus to resizing events.
		199
		200	When such an event happens, C<keep> will automatically trigger a
		201	reevaluation of the whole expression with the new value of the expression.
		202
		203	C<keep> is most useful for expensive operations, such as C<blur>:
		204
		205	rootalign keep { blur 20, root }
		206
		207	This makes a blurred copy of the root background once, and on subsequent
		208	calls, just root-aligns it. Since C<blur> is usually quite slow and
		209	C<rootalign> is quite fast, this trades extra memory (for the cached
		210	blurred pixmap) with speed (blur only needs to be redone when root
		211	changes).
		212
		213	=head3 C<load> caching
		214
		215	The C<load> operator itself does not keep images in memory, but as long as
		216	the image is still in memory, C<load> will use the in-memory image instead
		217	of loading it freshly from disk.
		218
		219	That means that this expression:
		220
		221	keep { load "$HOME/path..." }
		222
		223	Not only caches the image in memory, other terminal instances that try to
		224	C<load> it can reuse that in-memory copy.
175		225
176	=head1 REFERENCE	226	=head1 REFERENCE
177		227
178	=head2 COMMAND LINE SWITCHES	228	=head2 COMMAND LINE SWITCHES
179		229
…		…
191	Specifying this flag changes the behaviour, so that the image only	241	Specifying this flag changes the behaviour, so that the image only
192	replaces the background of the character area.	242	replaces the background of the character area.
193		243
194	=item --background-interval seconds	244	=item --background-interval seconds
195		245
196	Since some operations in the underlying XRender extension can effetively	246	Since some operations in the underlying XRender extension can effectively
197	freeze your X-server for prolonged time, this extension enforces a minimum	247	freeze your X-server for prolonged time, this extension enforces a minimum
198	time between updates, which is normally about 0.1 seconds.	248	time between updates, which is normally about 0.1 seconds.
199		249
200	If you want to do updates more often, you can decrease this safety	250	If you want to do updates more often, you can decrease this safety
201	interval with this switch.	251	interval with this switch.
202		252
203	=back	253	=back
204		254
205	=cut	255	=cut
206		256
207	our %_IMGCACHE;	257	our %_IMG_CACHE;
208	our $HOME;	258	our $HOME;
209	our ($self, $old, $new);	259	our ($self, $frame);
210	our ($x, $y, $w, $h);	260	our ($x, $y, $w, $h);
211		261
212	# enforce at least this interval between updates	262	# enforce at least this interval between updates
213	our $MIN_INTERVAL = 6/59.951;	263	our $MIN_INTERVAL = 6/59.951;
214		264
215	{	265	{
216	package urxvt::bgdsl; # background language	266	package urxvt::bgdsl; # background language
		267
		268	sub FR_PARENT() { 0 } # parent frame, if any - must be #0
		269	sub FR_CACHE () { 1 } # cached values
		270	sub FR_AGAIN () { 2 } # what this expr is sensitive to
		271	sub FR_STATE () { 3 } # watchers etc.
217		272
218	use List::Util qw(min max sum shuffle);	273	use List::Util qw(min max sum shuffle);
219		274
220	=head2 PROVIDERS/GENERATORS	275	=head2 PROVIDERS/GENERATORS
221		276
…		…
228	=item load $path	283	=item load $path
229		284
230	Loads the image at the given C<$path>. The image is set to plane tiling	285	Loads the image at the given C<$path>. The image is set to plane tiling
231	mode.	286	mode.
232		287
233	Loaded images will be cached for one cycle.	288	If the image is already in memory (e.g. because another terminal instance
		289	uses it), then the in-memory copy us returned instead.
234		290
		291	=item load_uc $path
		292
		293	Load uncached - same as load, but does not cache the image, which means it
		294	is I<always> loaded from the filesystem again, even if another copy of it
		295	is in memory at the time.
		296
235	=cut	297	=cut
		298
		299	sub load_uc($) {
		300	$self->new_img_from_file ($_[0])
		301	}
236		302
237	sub load($) {	303	sub load($) {
238	my ($path) = @_;	304	my ($path) = @_;
239		305
240	$new->{load}{$path} = $old->{load}{$path} \|\| $self->new_img_from_file ($path);	306	$_IMG_CACHE{$path} \|\| do {
		307	my $img = load_uc $path;
		308	Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
		309	$img
		310	}
241	}	311	}
242		312
243	=item root	313	=item root
244		314
245	Returns the root window pixmap, that is, hopefully, the background image	315	Returns the root window pixmap, that is, hopefully, the background image
246	of your screen. The image is set to extend mode.	316	of your screen.
247		317
248	This function makes your expression root sensitive, that means it will be	318	This function makes your expression root sensitive, that means it will be
249	reevaluated when the bg image changes.	319	reevaluated when the bg image changes.
250		320
251	=cut	321	=cut
252		322
253	sub root() {	323	sub root() {
254	$new->{rootpmap_sensitive} = 1;	324	$frame->[FR_AGAIN]{rootpmap} = 1;
255	die "root op not supported, exg, we need you";	325	$self->new_img_from_root
256	}	326	}
257		327
258	=item solid $colour	328	=item solid $colour
259		329
260	=item solid $width, $height, $colour	330	=item solid $width, $height, $colour
…		…
268	=cut	338	=cut
269		339
270	sub solid($;$$) {	340	sub solid($;$$) {
271	my $colour = pop;	341	my $colour = pop;
272		342
273	my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] \|\| 1, $_[1] \|\| 1);	343	my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] \|\| 1, $_[1] \|\| 1);
274	$img->fill ($colour);	344	$img->fill ($colour);
275	$img	345	$img
276	}	346	}
277		347
278	=item clone $img	348	=item clone $img
…		…
284		354
285	sub clone($) {	355	sub clone($) {
286	$_[0]->clone	356	$_[0]->clone
287	}	357	}
288		358
289	=back	359	=item merge $img ...
		360
		361	Takes any number of images and merges them together, creating a single
		362	image containing them all. The tiling mode of the first image is used as
		363	the tiling mode of the resulting image.
		364
		365	This function is called automatically when an expression returns multiple
		366	images.
		367
		368	=cut
		369
		370	sub merge(@) {
		371	return $_[0] unless $#_;
		372
		373	# rather annoyingly clumsy, but optimisation is for another time
		374
		375	my $x0 = +1e9;
		376	my $y0 = +1e9;
		377	my $x1 = -1e9;
		378	my $y1 = -1e9;
		379
		380	for (@_) {
		381	my ($x, $y, $w, $h) = $_->geometry;
		382
		383	$x0 = $x if $x0 > $x;
		384	$y0 = $y if $y0 > $y;
		385
		386	$x += $w;
		387	$y += $h;
		388
		389	$x1 = $x if $x1 < $x;
		390	$y1 = $y if $y1 < $y;
		391	}
		392
		393	my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
		394	$base->repeat_mode ($_[0]->repeat_mode);
		395	$base->fill ([0, 0, 0, 0]);
		396
		397	$base->draw ($_)
		398	for @_;
		399
		400	$base
		401	}
290		402
291	=head2 TILING MODES	403	=head2 TILING MODES
292		404
293	The following operators modify the tiling mode of an image, that is, the	405	The following operators modify the tiling mode of an image, that is, the
294	way that pixels outside the image area are painted when the image is used.	406	way that pixels outside the image area are painted when the image is used.
…		…
324	become transparent. This mode is most useful when you want to place an	436	become transparent. This mode is most useful when you want to place an
325	image over another image or the background colour while leaving all	437	image over another image or the background colour while leaving all
326	background pixels outside the image unchanged.	438	background pixels outside the image unchanged.
327		439
328	Example: load an image and display it in the upper left corner. The rest	440	Example: load an image and display it in the upper left corner. The rest
329	of the space is left "empty" (transparent or wahtever your compisotr does	441	of the space is left "empty" (transparent or whatever your compositor does
330	in alpha mode, else background colour).	442	in alpha mode, else background colour).
331		443
332	pad load "mybg.png"	444	pad load "mybg.png"
333		445
334	=item extend $img	446	=item extend $img
335		447
336	Extends the image over the whole plane, using the closest pixel in the	448	Extends the image over the whole plane, using the closest pixel in the
337	area outside the image. This mode is mostly useful when you more complex	449	area outside the image. This mode is mostly useful when you use more complex
338	filtering operations and want the pixels outside the image to have the	450	filtering operations and want the pixels outside the image to have the
339	same values as the pixels near the edge.	451	same values as the pixels near the edge.
340		452
341	Example: just for curiosity, how does this pixel extension stuff work?	453	Example: just for curiosity, how does this pixel extension stuff work?
342		454
…		…
391	Using these functions make your expression sensitive to window moves.	503	Using these functions make your expression sensitive to window moves.
392		504
393	These functions are mainly useful to align images to the root window.	505	These functions are mainly useful to align images to the root window.
394		506
395	Example: load an image and align it so it looks as if anchored to the	507	Example: load an image and align it so it looks as if anchored to the
396	background.	508	background (that's exactly what C<rootalign> does btw.):
397		509
398	move -TX, -TY, load "mybg.png"	510	move -TX, -TY, keep { load "mybg.png" }
399		511
400	=item TW	512	=item TW
401		513
402	Return the width (C<TW>) and height (C<TH>) of the terminal window (the	514	Return the width (C<TW>) and height (C<TH>) of the terminal window (the
403	terminal window is the full window by default, and the character area only	515	terminal window is the full window by default, and the character area only
…		…
409	the window size to conserve memory.	521	the window size to conserve memory.
410		522
411	Example: take the screen background, clip it to the window size, blur it a	523	Example: take the screen background, clip it to the window size, blur it a
412	bit, align it to the window position and use it as background.	524	bit, align it to the window position and use it as background.
413		525
414	clip move -TX, -TY, blur 5, root	526	clip move -TX, -TY, keep { blur 5, root }
415		527
416	=cut	528	=cut
417		529
418	sub TX() { $new->{position_sensitive} = 1; $x }	530	sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
419	sub TY() { $new->{position_sensitive} = 1; $y }	531	sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
420	sub TW() { $new->{size_sensitive} = 1; $w }	532	sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
421	sub TH() { $new->{size_sensitive} = 1; $h }	533	sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
422		534
423	=item now	535	=item now
424		536
425	Returns the current time as (fractional) seconds since the epoch.	537	Returns the current time as (fractional) seconds since the epoch.
426		538
…		…
433	C<$seconds> seconds.	545	C<$seconds> seconds.
434		546
435	Example: load some image and rotate it according to the time of day (as if it were	547	Example: load some image and rotate it according to the time of day (as if it were
436	the hour pointer of a clock). Update this image every minute.	548	the hour pointer of a clock). Update this image every minute.
437		549
		550	again 60;
438	again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"	551	rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
439		552
440	=item counter $seconds	553	=item counter $seconds
441		554
442	Like C<again>, but also returns an increasing counter value, starting at	555	Like C<again>, but also returns an increasing counter value, starting at
443	0, which might be useful for some simple animation effects.	556	0, which might be useful for some simple animation effects.
…		…
445	=cut	558	=cut
446		559
447	sub now() { urxvt::NOW }	560	sub now() { urxvt::NOW }
448		561
449	sub again($) {	562	sub again($) {
450	$new->{again} = $_[0];	563	$frame->[FR_AGAIN]{time} = $_[0];
451	}	564	}
452		565
453	sub counter($) {	566	sub counter($) {
454	$new->{again} = $_[0];	567	$frame->[FR_AGAIN]{time} = $_[0];
455	$self->{counter} + 0	568	$frame->[FR_STATE]{counter} + 0
456	}	569	}
457		570
458	=back	571	=back
459		572
460	=head2 SHAPE CHANGING OPERATORS	573	=head2 SHAPE CHANGING OPERATORS
…		…
480	assumed.	593	assumed.
481		594
482	Example: load an image, blur it, and clip it to the window size to save	595	Example: load an image, blur it, and clip it to the window size to save
483	memory.	596	memory.
484		597
485	clip blur 10, load "mybg.png"	598	clip keep { blur 10, load "mybg.png" }
486		599
487	=cut	600	=cut
488		601
489	sub clip($;$$;$$) {	602	sub clip($;$$;$$) {
490	my $img = pop;	603	my $img = pop;
…		…
584	the terminal window (or the box specified by C<$width> and C<$height> if	697	the terminal window (or the box specified by C<$width> and C<$height> if
585	given).	698	given).
586		699
587	Example: load an image and center it.	700	Example: load an image and center it.
588		701
589	center pad load "mybg.png"	702	center keep { pad load "mybg.png" }
590		703
591	=item rootalign $img	704	=item rootalign $img
592		705
593	Moves the image so that it appears glued to the screen as opposed to the	706	Moves the image so that it appears glued to the screen as opposed to the
594	window. This gives the illusion of a larger area behind the window. It is	707	window. This gives the illusion of a larger area behind the window. It is
595	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the	708	exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
596	top left of the screen.	709	top left of the screen.
597		710
598	Example: load a background image, put it in mirror mode and root align it.	711	Example: load a background image, put it in mirror mode and root align it.
599		712
600	rootalign mirror load "mybg.png"	713	rootalign keep { mirror load "mybg.png" }
601		714
602	Example: take the screen background and align it, giving the illusion of	715	Example: take the screen background and align it, giving the illusion of
603	transparency as long as the window isn't in front of other windows.	716	transparency as long as the window isn't in front of other windows.
604		717
605	rootalign root	718	rootalign root
…		…
630		743
631	sub rootalign($) {	744	sub rootalign($) {
632	move -TX, -TY, $_[0]	745	move -TX, -TY, $_[0]
633	}	746	}
634		747
		748	=item rotate $center_x, $center_y, $degrees, $img
		749
		750	Rotates the image clockwise by C<$degrees> degrees, around the point at
		751	C<$center_x> and C<$center_y> (specified as factor of image width/height).
		752
		753	Example: rotate the image by 90 degrees around it's center.
		754
		755	rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
		756
		757	=cut
		758
		759	sub rotate($$$$) {
		760	my $img = pop;
		761	$img->rotate (
		762	$_[0] * ($img->w + $img->x),
		763	$_[1] * ($img->h + $img->y),
		764	$_[2] * (3.14159265 / 180),
		765	)
		766	}
		767
635	=back	768	=back
636		769
637	=head2 COLOUR MODIFICATIONS	770	=head2 COLOUR MODIFICATIONS
638		771
639	The following operators change the pixels of the image.	772	The following operators change the pixels of the image.
640		773
641	=over 4	774	=over 4
		775
		776	=item tint $color, $img
		777
		778	Tints the image in the given colour.
		779
		780	Example: tint the image red.
		781
		782	tint "red", load "rgb.png"
		783
		784	Example: the same, but specify the colour by component.
		785
		786	tint [1, 0, 0], load "rgb.png"
		787
		788	=cut
		789
		790	sub tint($$) {
		791	$_[1]->tint ($_[0])
		792	}
642		793
643	=item contrast $factor, $img	794	=item contrast $factor, $img
644		795
645	=item contrast $r, $g, $b, $img	796	=item contrast $r, $g, $b, $img
646		797
…		…
673		824
674	Values less than 0 reduce brightness, while values larger than 0 increase	825	Values less than 0 reduce brightness, while values larger than 0 increase
675	it. Useful range is from -1 to 1 - the former results in a black, the	826	it. Useful range is from -1 to 1 - the former results in a black, the
676	latter in a white picture.	827	latter in a white picture.
677		828
678	Due to idiosynchrasies in the underlying XRender extension, biases less	829	Due to idiosyncrasies in the underlying XRender extension, biases less
679	than zero can be I<very> slow.	830	than zero can be I<very> slow.
680		831
681	=cut	832	=cut
682		833
683	sub contrast($$;$$;$) {	834	sub contrast($$;$$;$) {
…		…
721	sub blur($$;$) {	872	sub blur($$;$) {
722	my $img = pop;	873	my $img = pop;
723	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])	874	$img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
724	}	875	}
725		876
726	=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
727
728	Rotates the image by C<$degrees> degrees, counter-clockwise, around the
729	pointer at C<$center_x> and C<$center_y> (specified as factor of image
730	width/height), generating a new image with width C<$new_width> and height
731	C<$new_height>.
732
733	#TODO# new width, height, maybe more operators?
734
735	Example: rotate the image by 90 degrees
736
737	=cut
738
739	sub rotate($$$$$$) {
740	my $img = pop;
741	$img->rotate (
742	$_[0],
743	$_[1],
744	$_[2] * $img->w,
745	$_[3] * $img->h,
746	$_[4] * (3.14159265 / 180),
747	)
748	}
749
750	=back	877	=back
751		878
		879	=head2 OTHER STUFF
		880
		881	Anything that didn't fit any of the other categories, even after applying
		882	force and closing our eyes.
		883
		884	=over 4
		885
		886	=item keep { ... }
		887
		888	This operator takes a code block as argument, that is, one or more
		889	statements enclosed by braces.
		890
		891	The trick is that this code block is only evaluated when the outcome
		892	changes - on other calls the C<keep> simply returns the image it computed
		893	previously (yes, it should only be used with images). Or in other words,
		894	C<keep> I<caches> the result of the code block so it doesn't need to be
		895	computed again.
		896
		897	This can be extremely useful to avoid redoing slow operations - for
		898	example, if your background expression takes the root background, blurs it
		899	and then root-aligns it it would have to blur the root background on every
		900	window move or resize.
		901
		902	Another example is C<load>, which can be quite slow.
		903
		904	In fact, urxvt itself encloses the whole expression in some kind of
		905	C<keep> block so it only is reevaluated as required.
		906
		907	Putting the blur into a C<keep> block will make sure the blur is only done
		908	once, while the C<rootalign> is still done each time the window moves.
		909
		910	rootalign keep { blur 10, root }
		911
		912	This leaves the question of how to force reevaluation of the block,
		913	in case the root background changes: If expression inside the block
		914	is sensitive to some event (root background changes, window geometry
		915	changes), then it will be reevaluated automatically as needed.
		916
		917	=cut
		918
		919	sub keep(&) {
		920	my $id = $_[0]+0;
		921
		922	local $frame = $self->{frame_cache}{$id} \|\|= [$frame];
		923
		924	unless ($frame->[FR_CACHE]) {
		925	$frame->[FR_CACHE] = [ $_[0]() ];
		926
		927	my $self = $self;
		928	my $frame = $frame;
		929	Scalar::Util::weaken $frame;
		930	$self->compile_frame ($frame, sub {
		931	# clear this frame cache, also for all parents
		932	for (my $frame = $frame; $frame; $frame = $frame->[0]) {
		933	undef $frame->[FR_CACHE];
		934	}
		935
		936	$self->recalculate;
		937	});
		938	};
		939
		940	# in scalar context we always return the first original result, which
		941	# is not quite how perl works.
		942	wantarray
		943	? @{ $frame->[FR_CACHE] }
		944	: $frame->[FR_CACHE][0]
		945	}
		946
		947	# sub keep_clear() {
		948	# delete $self->{frame_cache};
		949	# }
		950
		951	=back
		952
752	=cut	953	=cut
753		954
754	}	955	}
755		956
756	sub parse_expr {	957	sub parse_expr {
757	my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}";	958	my $expr = eval
		959	"sub {\n"
		960	. "package urxvt::bgdsl;\n"
		961	. "#line 0 'background expression'\n"
		962	. "$_[0]\n"
		963	. "}";
758	die if $@;	964	die if $@;
759	$expr	965	$expr
760	}	966	}
761		967
762	# compiles a parsed expression	968	# compiles a parsed expression
763	sub set_expr {	969	sub set_expr {
764	my ($self, $expr) = @_;	970	my ($self, $expr) = @_;
765		971
		972	$self->{root} = []; # the outermost frame
766	$self->{expr} = $expr;	973	$self->{expr} = $expr;
767	$self->recalculate;	974	$self->recalculate;
		975	}
		976
		977	# takes a hash of sensitivity indicators and installs watchers
		978	sub compile_frame {
		979	my ($self, $frame, $cb) = @_;
		980
		981	my $state = $frame->[urxvt::bgdsl::FR_STATE] \|\|= {};
		982	my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
		983
		984	# don't keep stuff alive
		985	Scalar::Util::weaken $state;
		986
		987	if ($again->{nested}) {
		988	$state->{nested} = 1;
		989	} else {
		990	delete $state->{nested};
		991	}
		992
		993	if (my $interval = $again->{time}) {
		994	$state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
		995	if $state->{time}[0] != $interval;
		996
		997	# callback might have changed, although we could just rule that out
		998	$state->{time}[1]->cb (sub {
		999	++$state->{counter};
		1000	$cb->();
		1001	});
		1002	} else {
		1003	delete $state->{time};
		1004	}
		1005
		1006	if ($again->{position}) {
		1007	$state->{position} = $self->on (position_change => $cb);
		1008	} else {
		1009	delete $state->{position};
		1010	}
		1011
		1012	if ($again->{size}) {
		1013	$state->{size} = $self->on (size_change => $cb);
		1014	} else {
		1015	delete $state->{size};
		1016	}
		1017
		1018	if ($again->{rootpmap}) {
		1019	$state->{rootpmap} = $self->on (rootpmap_change => $cb);
		1020	} else {
		1021	delete $state->{rootpmap};
		1022	}
768	}	1023	}
769		1024
770	# evaluate the current bg expression	1025	# evaluate the current bg expression
771	sub recalculate {	1026	sub recalculate {
772	my ($arg_self) = @_;	1027	my ($arg_self) = @_;
…		…
782		1037
783	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;	1038	$arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
784		1039
785	# set environment to evaluate user expression	1040	# set environment to evaluate user expression
786		1041
787	local $self = $arg_self;	1042	local $self = $arg_self;
788
789	local $HOME = $ENV{HOME};	1043	local $HOME = $ENV{HOME};
790	local $old = $self->{state};	1044	local $frame = $self->{root};
791	local $new = my $state = $self->{state} = {};
792		1045
793	($x, $y, $w, $h) =
794	$self->background_geometry ($self->{border});	1046	($x, $y, $w, $h) = $self->background_geometry ($self->{border});
795		1047
796	# evaluate user expression	1048	# evaluate user expression
797		1049
798	my $img = eval { $self->{expr}->() };	1050	my @img = eval { $self->{expr}->() };
799	warn $@ if $@;#d#	1051	die $@ if $@;
800	die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";	1052	die "background-expr did not return anything.\n" unless @img;
		1053	die "background-expr: expected image(s), got something else.\n"
		1054	if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
801		1055
802	$state->{size_sensitive} = 1	1056	my $img = urxvt::bgdsl::merge @img;
		1057
		1058	$frame->[FR_AGAIN]{size} = 1
803	if $img->repeat_mode != urxvt::RepeatNormal;	1059	if $img->repeat_mode != urxvt::RepeatNormal;
804		1060
805	# if the expression is sensitive to external events, prepare reevaluation then	1061	# if the expression is sensitive to external events, prepare reevaluation then
806		1062	$self->compile_frame ($frame, sub { $arg_self->recalculate });
807	my $repeat;
808
809	if (my $again = $state->{again}) {
810	$repeat = 1;
811	my $self = $self;
812	$state->{timer} = $again == $old->{again}
813	? $old->{timer}
814	: urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
815	++$self->{counter};
816	$self->recalculate
817	});
818	}
819
820	if (delete $state->{position_sensitive}) {
821	$repeat = 1;
822	$self->enable (position_change => sub { $_[0]->recalculate });
823	} else {
824	$self->disable ("position_change");
825	}
826
827	if (delete $state->{size_sensitive}) {
828	$repeat = 1;
829	$self->enable (size_change => sub { $_[0]->recalculate });
830	} else {
831	$self->disable ("size_change");
832	}
833
834	if (delete $state->{rootpmap_sensitive}) {
835	$repeat = 1;
836	$self->enable (rootpmap_change => sub { $_[0]->recalculate });
837	} else {
838	$self->disable ("rootpmap_change");
839	}
840		1063
841	# clear stuff we no longer need	1064	# clear stuff we no longer need
842		1065
843	%$old = ();	1066	# unless (%{ $frame->[FR_STATE] }) {
844
845	unless ($repeat) {
846	delete $self->{state};	1067	# delete $self->{state};
847	delete $self->{expr};	1068	# delete $self->{expr};
848	}	1069	# }
849		1070
850	# set background pixmap	1071	# set background pixmap
851		1072
852	$self->set_background ($img, $self->{border});	1073	$self->set_background ($img, $self->{border});
853	$self->scr_recolour (0);	1074	$self->scr_recolour (0);

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Comparing rxvt-unicode/src/perl/background (file contents): Revision 1.50 by root, Sun Jun 10 17:31:53 2012 UTC vs. Revision 1.74 by root, Sat Jul 14 08:42:54 2012 UTC

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Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.50 by root, Sun Jun 10 17:31:53 2012 UTC vs.
Revision 1.74 by root, Sat Jul 14 08:42:54 2012 UTC