ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/rxvt-unicode/src/perl/background
(Generate patch)

Comparing rxvt-unicode/src/perl/background (file contents):
Revision 1.39 by root, Fri Jun 8 22:19:03 2012 UTC vs.
Revision 1.75 by root, Fri Aug 10 20:07:11 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
17=head1 QUICK AND DIRTY CHEAT SHEET
18
19Just load a random jpeg image and tile the background with it without
20scaling or anything else:
21
22 load "/path/to/img.jpg"
23
24The same, but use mirroring/reflection instead of tiling:
25
26 mirror load "/path/to/img.jpg"
27
28Load an image and scale it to exactly fill the terminal window:
29
30 scale keep { load "/path/to/img.jpg" }
31
32Implement pseudo-transparency by using a suitably-aligned root pixmap
33as window background:
34
35 rootalign root
36
37Likewise, but keep a blurred copy:
38
39 rootalign keep { blur 10, root }
40
15=head2 DESCRIPTION 41=head1 DESCRIPTION
16 42
17This extension manages the terminal background by creating a picture that 43This extension manages the terminal background by creating a picture that
18is behind the text, replacing the normal background colour. 44is behind the text, replacing the normal background colour.
19 45
20It does so by evaluating a Perl expression that I<calculates> the image on 46It does so by evaluating a Perl expression that I<calculates> the image on
24to be as simple as possible. 50to be as simple as possible.
25 51
26For example, to load an image and scale it to the window size, you would 52For example, to load an image and scale it to the window size, you would
27use: 53use:
28 54
29 urxvt --background-expr 'scale load "/path/to/mybg.png"' 55 urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
30 56
31Or specified as a X resource: 57Or specified as a X resource:
32 58
33 URxvt.background-expr: scale load "/path/to/mybg.png" 59 URxvt.background-expr: scale keep { load "/path/to/mybg.png" }
34 60
35=head2 THEORY OF OPERATION 61=head1 THEORY OF OPERATION
36 62
37At startup, just before the window is mapped for the first time, the 63At startup, just before the window is mapped for the first time, the
38expression is evaluated and must yield an image. The image is then 64expression is evaluated and must yield an image. The image is then
39extended as necessary to cover the whole terminal window, and is set as a 65extended as necessary to cover the whole terminal window, and is set as a
40background pixmap. 66background pixmap.
51If any of the parameters that the expression relies on changes (when the 77If any of the parameters that the expression relies on changes (when the
52window is moved or resized, its position or size changes; when the root 78window is moved or resized, its position or size changes; when the root
53pixmap is replaced by another one the root background changes; or when the 79pixmap is replaced by another one the root background changes; or when the
54timer elapses), then the expression will be evaluated again. 80timer elapses), then the expression will be evaluated again.
55 81
56For example, an expression such as C<scale load "$HOME/mybg.png"> scales the 82For example, an expression such as C<scale keep { load "$HOME/mybg.png"
57image to the window size, so it relies on the window size and will 83}> scales the image to the window size, so it relies on the window size
58be reevaluated each time it is changed, but not when it moves for 84and will be reevaluated each time it is changed, but not when it moves for
59example. That ensures that the picture always fills the terminal, even 85example. That ensures that the picture always fills the terminal, even
60after it's size changes. 86after its size changes.
61 87
62=head3 EXPRESSIONS 88=head2 EXPRESSIONS
63 89
64Expressions are normal Perl expressions, in fact, they are Perl blocks - 90Expressions are normal Perl expressions, in fact, they are Perl blocks -
65which means you could use multiple lines and statements: 91which means you could use multiple lines and statements:
66 92
93 scale keep {
67 again 3600; 94 again 3600;
68 if (localtime now)[6]) { 95 if (localtime now)[6]) {
69 return scale load "$HOME/weekday.png"; 96 return load "$HOME/weekday.png";
70 } else { 97 } else {
71 return scale load "$HOME/sunday.png"; 98 return load "$HOME/sunday.png";
99 }
72 } 100 }
73 101
74This expression gets evaluated once per hour. It will set F<sunday.png> as 102This inner expression is evaluated once per hour (and whenever the
103terminal window is resized). It sets F<sunday.png> as background on
75background on Sundays, and F<weekday.png> on all other days. 104Sundays, and F<weekday.png> on all other days.
76 105
77Fortunately, we expect that most expressions will be much simpler, with 106Fortunately, we expect that most expressions will be much simpler, with
78little Perl knowledge needed. 107little Perl knowledge needed.
79 108
80Basically, you always start with a function that "generates" an image 109Basically, you always start with a function that "generates" an image
97its result becomes the argument to the C<scale> function. 126its result becomes the argument to the C<scale> function.
98 127
99Many operators also allow some parameters preceding the input image 128Many operators also allow some parameters preceding the input image
100that modify its behaviour. For example, C<scale> without any additional 129that modify its behaviour. For example, C<scale> without any additional
101arguments scales the image to size of the terminal window. If you specify 130arguments scales the image to size of the terminal window. If you specify
102an additional argument, it uses it as a percentage: 131an additional argument, it uses it as a scale factor (multiply by 100 to
132get a percentage):
103 133
104 scale 200, load "$HOME/mypic.png" 134 scale 2, load "$HOME/mypic.png"
105 135
106This enlarges the image by a factor of 2 (200%). As you can see, C<scale> 136This enlarges the image by a factor of 2 (200%). As you can see, C<scale>
107has now two arguments, the C<200> and the C<load> expression, while 137has now two arguments, the C<200> and the C<load> expression, while
108C<load> only has one argument. Arguments are separated from each other by 138C<load> only has one argument. Arguments are separated from each other by
109commas. 139commas.
110 140
111Scale also accepts two arguments, which are then separate factors for both 141Scale also accepts two arguments, which are then separate factors for both
112horizontal and vertical dimensions. For example, this halves the image 142horizontal and vertical dimensions. For example, this halves the image
113width and doubles the image height: 143width and doubles the image height:
114 144
115 scale 50, 200, load "$HOME/mypic.png" 145 scale 0.5, 2, load "$HOME/mypic.png"
116 146
117Other effects than scalign are also readily available, for exmaple, you can 147IF you try out these expressions, you might suffer from some sluggishness,
118tile the image to fill the whole window, instead of resizing it: 148because each time the terminal is resized, it loads the PNG image again
149and scales it. Scaling is usually fast (and unavoidable), but loading the
150image can be quite time consuming. This is where C<keep> comes in handy:
119 151
152 scale 0.5, 2, keep { load "$HOME/mypic.png" }
153
154The C<keep> operator executes all the statements inside the braces only
155once, or when it thinks the outcome might change. In other cases it
156returns the last value computed by the brace block.
157
158This means that the C<load> is only executed once, which makes it much
159faster, but also means that more memory is being used, because the loaded
160image must be kept in memory at all times. In this expression, the
161trade-off is likely worth it.
162
163But back to effects: Other effects than scaling are also readily
164available, for example, you can tile the image to fill the whole window,
165instead of resizing it:
166
120 tile load "$HOME/mypic.png" 167 tile keep { load "$HOME/mypic.png" }
121 168
122In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator 169In fact, images returned by C<load> are in C<tile> mode by default, so the
123is kind of superfluous. 170C<tile> operator is kind of superfluous.
124 171
125Another common effect is to mirror the image, so that the same edges touch: 172Another common effect is to mirror the image, so that the same edges
173touch:
126 174
127 mirror load "$HOME/mypic.png" 175 mirror keep { load "$HOME/mypic.png" }
128 176
129This is also a typical background expression: 177Another common background expression is:
130 178
131 rootalign root 179 rootalign root
132 180
133It first takes a snapshot of the screen background image, and then 181This one first takes a snapshot of the screen background image, and then
134moves it to the upper left corner of the screen - the result is 182moves it to the upper left corner of the screen (as opposed to the upper
135pseudo-transparency, as the image seems to be static while the window is 183left corner of the terminal window)- the result is pseudo-transparency:
136moved around. 184the image seems to be static while the window is moved around.
137 185
138=head3 CYCLES AND CACHING 186=head2 COLOUR SPECIFICATIONS
139 187
140As has been mentioned before, the expression might be evaluated multiple 188Whenever an operator expects a "colour", then this can be specified in one
141times. Each time the expression is reevaluated, a new cycle is said to 189of two ways: Either as string with an X11 colour specification, such as:
142have begun. Many operators cache their results till the next cycle.
143 190
144For example, the C<load> operator keeps a copy of the image. If it is 191 "red" # named colour
145asked to load the same image on the next cycle it will not load it again, 192 "#f00" # simple rgb
146but return the cached copy. 193 "[50]red" # red with 50% alpha
194 "TekHVC:300/50/50" # anything goes
147 195
148This only works for one cycle though, so as long as you load the same 196OR as an array reference with one, three or four components:
149image every time, it will always be cached, but when you load a different
150image, it will forget about the first one.
151 197
152This allows you to either speed things up by keeping multiple images in 198 [0.5] # 50% gray, 100% alpha
153memory, or comserve memory by loading images more often. 199 [0.5, 0, 0] # dark red, no green or blur, 100% alpha
200 [0.5, 0, 0, 0.7] # same with explicit 70% alpha
154 201
155For example, you can keep two images in memory and use a random one like 202=head2 CACHING AND SENSITIVITY
156this:
157 203
158 my $img1 = load "img1.png"; 204Since some operations (such as C<load> and C<blur>) can take a long time,
159 my $img2 = load "img2.png"; 205caching results can be very important for a smooth operation. Caching can
160 (0.5 > rand) ? $img1 : $img2 206also be useful to reduce memory usage, though, for example, when an image
207is cached by C<load>, it could be shared by multiple terminal windows
208running inside urxvtd.
161 209
162Since both images are "loaded" every time the expression is evaluated, 210=head3 C<keep { ... }> caching
163they are always kept in memory. Contrast this version:
164 211
165 my $path1 = "img1.png"; 212The most important way to cache expensive operations is to use C<keep {
166 my $path2 = "img2.png"; 213... }>. The C<keep> operator takes a block of multiple statements enclosed
167 load ((0.5 > rand) ? $path1 : $path2) 214by C<{}> and keeps the return value in memory.
168 215
169Here, a path is selected randomly, and load is only called for one image, 216An expression can be "sensitive" to various external events, such as
170so keeps only one image in memory. If, on the next evaluation, luck 217scaling or moving the window, root background changes and timers. Simply
171decides to use the other path, then it will have to load that image again. 218using an expression (such as C<scale> without parameters) that depends on
219certain changing values (called "variables"), or using those variables
220directly, will make an expression sensitive to these events - for example,
221using C<scale> or C<TW> will make the expression sensitive to the terminal
222size, and thus to resizing events.
172 223
224When such an event happens, C<keep> will automatically trigger a
225reevaluation of the whole expression with the new value of the expression.
226
227C<keep> is most useful for expensive operations, such as C<blur>:
228
229 rootalign keep { blur 20, root }
230
231This makes a blurred copy of the root background once, and on subsequent
232calls, just root-aligns it. Since C<blur> is usually quite slow and
233C<rootalign> is quite fast, this trades extra memory (for the cached
234blurred pixmap) with speed (blur only needs to be redone when root
235changes).
236
237=head3 C<load> caching
238
239The C<load> operator itself does not keep images in memory, but as long as
240the image is still in memory, C<load> will use the in-memory image instead
241of loading it freshly from disk.
242
243That means that this expression:
244
245 keep { load "$HOME/path..." }
246
247Not only caches the image in memory, other terminal instances that try to
248C<load> it can reuse that in-memory copy.
249
173=head2 REFERENCE 250=head1 REFERENCE
174 251
175=head3 COMMAND LINE SWITCHES 252=head2 COMMAND LINE SWITCHES
176 253
177=over 4 254=over 4
178 255
179=item --background-expr perl-expression 256=item --background-expr perl-expression
180 257
186overwriting borders and any other areas, such as the scrollbar. 263overwriting borders and any other areas, such as the scrollbar.
187 264
188Specifying this flag changes the behaviour, so that the image only 265Specifying this flag changes the behaviour, so that the image only
189replaces the background of the character area. 266replaces the background of the character area.
190 267
268=item --background-interval seconds
269
270Since some operations in the underlying XRender extension can effectively
271freeze your X-server for prolonged time, this extension enforces a minimum
272time between updates, which is normally about 0.1 seconds.
273
274If you want to do updates more often, you can decrease this safety
275interval with this switch.
276
191=back 277=back
192 278
193=cut 279=cut
194 280
281our %_IMG_CACHE;
195our $HOME; 282our $HOME;
196our ($self, $old, $new); 283our ($self, $frame);
197our ($x, $y, $w, $h); 284our ($x, $y, $w, $h);
198 285
199# enforce at least this interval between updates 286# enforce at least this interval between updates
200our $MIN_INTERVAL = 1/100; 287our $MIN_INTERVAL = 6/59.951;
201 288
202{ 289{
203 package urxvt::bgdsl; # background language 290 package urxvt::bgdsl; # background language
291
292 sub FR_PARENT() { 0 } # parent frame, if any - must be #0
293 sub FR_CACHE () { 1 } # cached values
294 sub FR_AGAIN () { 2 } # what this expr is sensitive to
295 sub FR_STATE () { 3 } # watchers etc.
296
297 use List::Util qw(min max sum shuffle);
204 298
205=head2 PROVIDERS/GENERATORS 299=head2 PROVIDERS/GENERATORS
206 300
207These functions provide an image, by loading it from disk, grabbing it 301These functions provide an image, by loading it from disk, grabbing it
208from the root screen or by simply generating it. They are used as starting 302from the root screen or by simply generating it. They are used as starting
213=item load $path 307=item load $path
214 308
215Loads the image at the given C<$path>. The image is set to plane tiling 309Loads the image at the given C<$path>. The image is set to plane tiling
216mode. 310mode.
217 311
218Loaded images will be cached for one cycle. 312If the image is already in memory (e.g. because another terminal instance
313uses it), then the in-memory copy us returned instead.
219 314
315=item load_uc $path
316
317Load uncached - same as load, but does not cache the image, which means it
318is I<always> loaded from the filesystem again, even if another copy of it
319is in memory at the time.
320
220=cut 321=cut
322
323 sub load_uc($) {
324 $self->new_img_from_file ($_[0])
325 }
221 326
222 sub load($) { 327 sub load($) {
223 my ($path) = @_; 328 my ($path) = @_;
224 329
225 $new->{load}{$path} = $old->{load}{$path} || $self->new_img_from_file ($path); 330 $_IMG_CACHE{$path} || do {
331 my $img = load_uc $path;
332 Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
333 $img
334 }
226 } 335 }
227 336
228=item root 337=item root
229 338
230Returns the root window pixmap, that is, hopefully, the background image 339Returns the root window pixmap, that is, hopefully, the background image
231of your screen. The image is set to extend mode. 340of your screen.
232 341
233This function makes your expression root sensitive, that means it will be 342This function makes your expression root sensitive, that means it will be
234reevaluated when the bg image changes. 343reevaluated when the bg image changes.
235 344
236=cut 345=cut
237 346
238 sub root() { 347 sub root() {
239 $new->{rootpmap_sensitive} = 1; 348 $frame->[FR_AGAIN]{rootpmap} = 1;
240 die "root op not supported, exg, we need you"; 349 $self->new_img_from_root
241 } 350 }
242 351
243=item solid $colour 352=item solid $colour
244 353
245=item solid $width, $height, $colour 354=item solid $width, $height, $colour
246 355
247Creates a new image and completely fills it with the given colour. The 356Creates a new image and completely fills it with the given colour. The
248image is set to tiling mode. 357image is set to tiling mode.
249 358
250If <$width> and C<$height> are omitted, it creates a 1x1 image, which is 359If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
251useful for solid backgrounds or for use in filtering effects. 360useful for solid backgrounds or for use in filtering effects.
252 361
253=cut 362=cut
254 363
255 sub solid($$;$) { 364 sub solid($;$$) {
256 my $colour = pop; 365 my $colour = pop;
257 366
258 my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] || 1, $_[1] || 1); 367 my $img = $self->new_img (urxvt::PictStandardARGB32, 0, 0, $_[0] || 1, $_[1] || 1);
259 $img->fill ($colour); 368 $img->fill ($colour);
260 $img 369 $img
261 } 370 }
262 371
263=back 372=item clone $img
264 373
265=head2 VARIABLES 374Returns an exact copy of the image. This is useful if you want to have
375multiple copies of the same image to apply different effects to.
266 376
267The following functions provide variable data such as the terminal
268window dimensions. Most of them make your expression sensitive to some
269events, for example using C<TW> (terminal width) means your expression is
270evaluated again when the terminal is resized.
271
272=over 4
273
274=item TX
275
276=item TY
277
278Return the X and Y coordinates of the terminal window (the terminal
279window is the full window by default, and the character area only when in
280border-respect mode).
281
282Using these functions make your expression sensitive to window moves.
283
284These functions are mainly useful to align images to the root window.
285
286Example: load an image and align it so it looks as if anchored to the
287background.
288
289 move -TX, -TY, load "mybg.png"
290
291=item TW
292
293Return the width (C<TW>) and height (C<TH>) of the terminal window (the
294terminal window is the full window by default, and the character area only
295when in border-respect mode).
296
297Using these functions make your expression sensitive to window resizes.
298
299These functions are mainly useful to scale images, or to clip images to
300the window size to conserve memory.
301
302Example: take the screen background, clip it to the window size, blur it a
303bit, align it to the window position and use it as background.
304
305 clip move -TX, -TY, blur 5, root
306
307=cut 377=cut
308 378
309 sub TX() { $new->{position_sensitive} = 1; $x }
310 sub TY() { $new->{position_sensitive} = 1; $y }
311 sub TW() { $new->{size_sensitive} = 1; $w }
312 sub TH() { $new->{size_sensitive} = 1; $h }
313
314=item now
315
316Returns the current time as (fractional) seconds since the epoch.
317
318Using this expression does I<not> make your expression sensitive to time,
319but the next two functions do.
320
321=item again $seconds
322
323When this function is used the expression will be reevaluated again in
324C<$seconds> seconds.
325
326Example: load some image and rotate it according to the time of day (as if it were
327the hour pointer of a clock). Update this image every minute.
328
329 again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png"
330
331=item counter $seconds
332
333Like C<again>, but also returns an increasing counter value, starting at
3340, which might be useful for some simple animation effects.
335
336=cut
337
338 sub now() { urxvt::NOW }
339
340 sub again($) {
341 $new->{again} = $_[0];
342 }
343
344 sub counter($) { 379 sub clone($) {
345 $new->{again} = $_[0]; 380 $_[0]->clone
346 $self->{counter} + 0
347 } 381 }
348 382
349=back 383=item merge $img ...
384
385Takes any number of images and merges them together, creating a single
386image containing them all. The tiling mode of the first image is used as
387the tiling mode of the resulting image.
388
389This function is called automatically when an expression returns multiple
390images.
391
392=cut
393
394 sub merge(@) {
395 return $_[0] unless $#_;
396
397 # rather annoyingly clumsy, but optimisation is for another time
398
399 my $x0 = +1e9;
400 my $y0 = +1e9;
401 my $x1 = -1e9;
402 my $y1 = -1e9;
403
404 for (@_) {
405 my ($x, $y, $w, $h) = $_->geometry;
406
407 $x0 = $x if $x0 > $x;
408 $y0 = $y if $y0 > $y;
409
410 $x += $w;
411 $y += $h;
412
413 $x1 = $x if $x1 < $x;
414 $y1 = $y if $y1 < $y;
415 }
416
417 my $base = $self->new_img (urxvt::PictStandardARGB32, $x0, $y0, $x1 - $x0, $y1 - $y0);
418 $base->repeat_mode ($_[0]->repeat_mode);
419 $base->fill ([0, 0, 0, 0]);
420
421 $base->draw ($_)
422 for @_;
423
424 $base
425 }
350 426
351=head2 TILING MODES 427=head2 TILING MODES
352 428
353The following operators modify the tiling mode of an image, that is, the 429The following operators modify the tiling mode of an image, that is, the
354way that pixels outside the image area are painted when the image is used. 430way that pixels outside the image area are painted when the image is used.
384become transparent. This mode is most useful when you want to place an 460become transparent. This mode is most useful when you want to place an
385image over another image or the background colour while leaving all 461image over another image or the background colour while leaving all
386background pixels outside the image unchanged. 462background pixels outside the image unchanged.
387 463
388Example: load an image and display it in the upper left corner. The rest 464Example: load an image and display it in the upper left corner. The rest
389of the space is left "empty" (transparent or wahtever your compisotr does 465of the space is left "empty" (transparent or whatever your compositor does
390in alpha mode, else background colour). 466in alpha mode, else background colour).
391 467
392 pad load "mybg.png" 468 pad load "mybg.png"
393 469
394=item extend $img 470=item extend $img
395 471
396Extends the image over the whole plane, using the closest pixel in the 472Extends the image over the whole plane, using the closest pixel in the
397area outside the image. This mode is mostly useful when you more complex 473area outside the image. This mode is mostly useful when you use more complex
398filtering operations and want the pixels outside the image to have the 474filtering operations and want the pixels outside the image to have the
399same values as the pixels near the edge. 475same values as the pixels near the edge.
400 476
401Example: just for curiosity, how does this pixel extension stuff work? 477Example: just for curiosity, how does this pixel extension stuff work?
402 478
428 $img 504 $img
429 } 505 }
430 506
431=back 507=back
432 508
433=head2 PIXEL OPERATORS 509=head2 VARIABLE VALUES
434 510
435The following operators modify the image pixels in various ways. 511The following functions provide variable data such as the terminal window
512dimensions. They are not (Perl-) variables, they just return stuff that
513varies. Most of them make your expression sensitive to some events, for
514example using C<TW> (terminal width) means your expression is evaluated
515again when the terminal is resized.
436 516
437=over 4 517=over 4
438 518
439=item clone $img 519=item TX
440 520
441Returns an exact copy of the image. 521=item TY
442 522
443=cut 523Return the X and Y coordinates of the terminal window (the terminal
524window is the full window by default, and the character area only when in
525border-respect mode).
444 526
527Using these functions make your expression sensitive to window moves.
528
529These functions are mainly useful to align images to the root window.
530
531Example: load an image and align it so it looks as if anchored to the
532background (that's exactly what C<rootalign> does btw.):
533
534 move -TX, -TY, keep { load "mybg.png" }
535
536=item TW
537
538Return the width (C<TW>) and height (C<TH>) of the terminal window (the
539terminal window is the full window by default, and the character area only
540when in border-respect mode).
541
542Using these functions make your expression sensitive to window resizes.
543
544These functions are mainly useful to scale images, or to clip images to
545the window size to conserve memory.
546
547Example: take the screen background, clip it to the window size, blur it a
548bit, align it to the window position and use it as background.
549
550 clip move -TX, -TY, keep { blur 5, root }
551
552=cut
553
554 sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
555 sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
556 sub TW() { $frame->[FR_AGAIN]{size} = 1; $w }
557 sub TH() { $frame->[FR_AGAIN]{size} = 1; $h }
558
559=item now
560
561Returns the current time as (fractional) seconds since the epoch.
562
563Using this expression does I<not> make your expression sensitive to time,
564but the next two functions do.
565
566=item again $seconds
567
568When this function is used the expression will be reevaluated again in
569C<$seconds> seconds.
570
571Example: load some image and rotate it according to the time of day (as if it were
572the hour pointer of a clock). Update this image every minute.
573
574 again 60;
575 rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
576
577=item counter $seconds
578
579Like C<again>, but also returns an increasing counter value, starting at
5800, which might be useful for some simple animation effects.
581
582=cut
583
584 sub now() { urxvt::NOW }
585
586 sub again($) {
587 $frame->[FR_AGAIN]{time} = $_[0];
588 }
589
445 sub clone($) { 590 sub counter($) {
446 $_[0]->clone 591 $frame->[FR_AGAIN]{time} = $_[0];
592 $frame->[FR_STATE]{counter} + 0
447 } 593 }
594
595=back
596
597=head2 SHAPE CHANGING OPERATORS
598
599The following operators modify the shape, size or position of the image.
600
601=over 4
448 602
449=item clip $img 603=item clip $img
450 604
451=item clip $width, $height, $img 605=item clip $width, $height, $img
452 606
463assumed. 617assumed.
464 618
465Example: load an image, blur it, and clip it to the window size to save 619Example: load an image, blur it, and clip it to the window size to save
466memory. 620memory.
467 621
468 clip blur 10, load "mybg.png" 622 clip keep { blur 10, load "mybg.png" }
469 623
470=cut 624=cut
471 625
472 sub clip($;$$;$$) { 626 sub clip($;$$;$$) {
473 my $img = pop; 627 my $img = pop;
476 $img->sub_rect ($_[0], $_[1], $w, $h) 630 $img->sub_rect ($_[0], $_[1], $w, $h)
477 } 631 }
478 632
479=item scale $img 633=item scale $img
480 634
481=item scale $size_percent, $img 635=item scale $size_factor, $img
482 636
483=item scale $width_percent, $height_percent, $img 637=item scale $width_factor, $height_factor, $img
484 638
485Scales the image by the given percentages in horizontal 639Scales the image by the given factors in horizontal
486(C<$width_percent>) and vertical (C<$height_percent>) direction. 640(C<$width>) and vertical (C<$height>) direction.
487 641
488If only one percentage is give, it is used for both directions. 642If only one factor is give, it is used for both directions.
489 643
490If no percentages are given, scales the image to the window size without 644If no factors are given, scales the image to the window size without
491keeping aspect. 645keeping aspect.
492 646
493=item resize $width, $height, $img 647=item resize $width, $height, $img
494 648
495Resizes the image to exactly C<$width> times C<$height> pixels. 649Resizes the image to exactly C<$width> times C<$height> pixels.
496 650
497=cut 651=item fit $img
498 652
499#TODO: maximise, maximise_fill? 653=item fit $width, $height, $img
654
655Fits the image into the given C<$width> and C<$height> without changing
656aspect, or the terminal size. That means it will be shrunk or grown until
657the whole image fits into the given area, possibly leaving borders.
658
659=item cover $img
660
661=item cover $width, $height, $img
662
663Similar to C<fit>, but shrinks or grows until all of the area is covered
664by the image, so instead of potentially leaving borders, it will cut off
665image data that doesn't fit.
666
667=cut
500 668
501 sub scale($;$;$) { 669 sub scale($;$;$) {
502 my $img = pop; 670 my $img = pop;
503 671
504 @_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01) 672 @_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
505 : @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01) 673 : @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
506 : $img->scale (TW, TH) 674 : $img->scale (TW, TH)
507 } 675 }
508 676
509 sub resize($$$) { 677 sub resize($$$) {
510 my $img = pop; 678 my $img = pop;
511 $img->scale ($_[0], $_[1]) 679 $img->scale ($_[0], $_[1])
512 } 680 }
513 681
682 sub fit($;$$) {
683 my $img = pop;
684 my $w = ($_[0] || TW) / $img->w;
685 my $h = ($_[1] || TH) / $img->h;
686 scale +(min $w, $h), $img
687 }
688
689 sub cover($;$$) {
690 my $img = pop;
691 my $w = ($_[0] || TW) / $img->w;
692 my $h = ($_[1] || TH) / $img->h;
693 scale +(max $w, $h), $img
694 }
695
514=item move $dx, $dy, $img 696=item move $dx, $dy, $img
515 697
516Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in 698Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
517the vertical. 699the vertical.
518 700
519Example: move the image right by 20 pixels and down by 30. 701Example: move the image right by 20 pixels and down by 30.
520 702
521 move 20, 30, ... 703 move 20, 30, ...
704
705=item align $xalign, $yalign, $img
706
707Aligns the image according to a factor - C<0> means the image is moved to
708the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
709exactly centered and C<1> means it touches the right or bottom edge.
710
711Example: remove any visible border around an image, center it vertically but move
712it to the right hand side.
713
714 align 1, 0.5, pad $img
715
716=item center $img
717
718=item center $width, $height, $img
719
720Centers the image, i.e. the center of the image is moved to the center of
721the terminal window (or the box specified by C<$width> and C<$height> if
722given).
723
724Example: load an image and center it.
725
726 center keep { pad load "mybg.png" }
522 727
523=item rootalign $img 728=item rootalign $img
524 729
525Moves the image so that it appears glued to the screen as opposed to the 730Moves the image so that it appears glued to the screen as opposed to the
526window. This gives the illusion of a larger area behind the window. It is 731window. This gives the illusion of a larger area behind the window. It is
527exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the 732exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
528top left of the screen. 733top left of the screen.
529 734
530Example: load a background image, put it in mirror mode and root align it. 735Example: load a background image, put it in mirror mode and root align it.
531 736
532 rootalign mirror load "mybg.png" 737 rootalign keep { mirror load "mybg.png" }
533 738
534Example: take the screen background and align it, giving the illusion of 739Example: take the screen background and align it, giving the illusion of
535transparency as long as the window isn't in front of other windows. 740transparency as long as the window isn't in front of other windows.
536 741
537 rootalign root 742 rootalign root
538 743
539=cut 744=cut
540 745
541 sub move($$;$) { 746 sub move($$;$) {
542 my $img = pop->clone; 747 my $img = pop->clone;
543 $img->move ($_[0], $_[1]); 748 $img->move ($_[0], $_[1]);
544 $img 749 $img
545 } 750 }
546 751
752 sub align($;$$) {
753 my $img = pop;
754
755 move $_[0] * (TW - $img->w),
756 $_[1] * (TH - $img->h),
757 $img
758 }
759
760 sub center($;$$) {
761 my $img = pop;
762 my $w = $_[0] || TW;
763 my $h = $_[1] || TH;
764
765 move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
766 }
767
547 sub rootalign($) { 768 sub rootalign($) {
548 move -TX, -TY, $_[0] 769 move -TX, -TY, $_[0]
549 } 770 }
550 771
772=item rotate $center_x, $center_y, $degrees, $img
773
774Rotates the image clockwise by C<$degrees> degrees, around the point at
775C<$center_x> and C<$center_y> (specified as factor of image width/height).
776
777Example: rotate the image by 90 degrees around it's center.
778
779 rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
780
781=cut
782
783 sub rotate($$$$) {
784 my $img = pop;
785 $img->rotate (
786 $_[0] * ($img->w + $img->x),
787 $_[1] * ($img->h + $img->y),
788 $_[2] * (3.14159265 / 180),
789 )
790 }
791
792=back
793
794=head2 COLOUR MODIFICATIONS
795
796The following operators change the pixels of the image.
797
798=over 4
799
800=item tint $color, $img
801
802Tints the image in the given colour.
803
804Example: tint the image red.
805
806 tint "red", load "rgb.png"
807
808Example: the same, but specify the colour by component.
809
810 tint [1, 0, 0], load "rgb.png"
811
812=cut
813
814 sub tint($$) {
815 $_[1]->tint ($_[0])
816 }
817
551=item contrast $factor, $img 818=item contrast $factor, $img
552 819
553=item contrast $r, $g, $b, $img 820=item contrast $r, $g, $b, $img
554 821
555=item contrast $r, $g, $b, $a, $img 822=item contrast $r, $g, $b, $a, $img
556 823
557Adjusts the I<contrast> of an image. 824Adjusts the I<contrast> of an image.
558 825
559#TODO# 826The first form applies a single C<$factor> to red, green and blue, the
827second form applies separate factors to each colour channel, and the last
828form includes the alpha channel.
560 829
830Values from 0 to 1 lower the contrast, values higher than 1 increase the
831contrast.
832
833Due to limitations in the underlying XRender extension, lowering contrast
834also reduces brightness, while increasing contrast currently also
835increases brightness.
836
561=item brightness $factor, $img 837=item brightness $bias, $img
562 838
563=item brightness $r, $g, $b, $img 839=item brightness $r, $g, $b, $img
564 840
565=item brightness $r, $g, $b, $a, $img 841=item brightness $r, $g, $b, $a, $img
566 842
567Adjusts the brightness of an image. 843Adjusts the brightness of an image.
844
845The first form applies a single C<$bias> to red, green and blue, the
846second form applies separate biases to each colour channel, and the last
847form includes the alpha channel.
848
849Values less than 0 reduce brightness, while values larger than 0 increase
850it. Useful range is from -1 to 1 - the former results in a black, the
851latter in a white picture.
852
853Due to idiosyncrasies in the underlying XRender extension, biases less
854than zero can be I<very> slow.
855
856You can also try the experimental(!) C<muladd> operator.
568 857
569=cut 858=cut
570 859
571 sub contrast($$;$$;$) { 860 sub contrast($$;$$;$) {
572 my $img = pop; 861 my $img = pop;
573 my ($r, $g, $b, $a) = @_; 862 my ($r, $g, $b, $a) = @_;
574 863
575 ($g, $b) = ($r, $r) if @_ < 4; 864 ($g, $b) = ($r, $r) if @_ < 3;
576 $a = 1 if @_ < 5; 865 $a = 1 if @_ < 4;
577 866
578 $img = $img->clone; 867 $img = $img->clone;
579 $img->contrast ($r, $g, $b, $a); 868 $img->contrast ($r, $g, $b, $a);
580 $img 869 $img
581 } 870 }
582 871
583 sub brightness($$;$$;$) { 872 sub brightness($$;$$;$) {
584 my $img = pop; 873 my $img = pop;
585 my ($r, $g, $b, $a) = @_; 874 my ($r, $g, $b, $a) = @_;
586 875
587 ($g, $b) = ($r, $r) if @_ < 4; 876 ($g, $b) = ($r, $r) if @_ < 3;
588 $a = 1 if @_ < 5; 877 $a = 1 if @_ < 4;
589 878
590 $img = $img->clone; 879 $img = $img->clone;
591 $img->brightness ($r, $g, $b, $a); 880 $img->brightness ($r, $g, $b, $a);
592 $img 881 $img
882 }
883
884=item muladd $mul, $add, $img # EXPERIMENTAL
885
886First multipliesthe pixels by C<$mul>, then adds C<$add>. This cna be used
887to implement brightness and contrast at the same time, with a wider value
888range than contrast and brightness operators.
889
890Due to numerous bugs in XRender implementations, it can also introduce a
891number of visual artifacts.
892
893Example: increase contrast by a factor of C<$c> without changing image
894brightness too much.
895
896 muladd $c, (1 - $c) * 0.5, $img
897
898=cut
899
900 sub muladd($$$) {
901 $_[2]->muladd ($_[0], $_[1])
593 } 902 }
594 903
595=item blur $radius, $img 904=item blur $radius, $img
596 905
597=item blur $radius_horz, $radius_vert, $img 906=item blur $radius_horz, $radius_vert, $img
609 sub blur($$;$) { 918 sub blur($$;$) {
610 my $img = pop; 919 my $img = pop;
611 $img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0]) 920 $img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
612 } 921 }
613 922
614=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
615
616Rotates the image by C<$degrees> degrees, counter-clockwise, around the
617pointer at C<$center_x> and C<$center_y> (specified as percentage of image
618width/height), generating a new image with width C<$new_width> and height
619C<$new_height>.
620
621#TODO# new width, height, maybe more operators?
622
623Example: rotate the image by 90 degrees
624
625=cut
626
627 sub rotate($$$$$$) {
628 my $img = pop;
629 $img->rotate (
630 $_[0],
631 $_[1],
632 $_[2] * $img->w * .01,
633 $_[3] * $img->h * .01,
634 $_[4] * (3.14159265 / 180),
635 )
636 }
637
638=back 923=back
639 924
925=head2 OTHER STUFF
926
927Anything that didn't fit any of the other categories, even after applying
928force and closing our eyes.
929
930=over 4
931
932=item keep { ... }
933
934This operator takes a code block as argument, that is, one or more
935statements enclosed by braces.
936
937The trick is that this code block is only evaluated when the outcome
938changes - on other calls the C<keep> simply returns the image it computed
939previously (yes, it should only be used with images). Or in other words,
940C<keep> I<caches> the result of the code block so it doesn't need to be
941computed again.
942
943This can be extremely useful to avoid redoing slow operations - for
944example, if your background expression takes the root background, blurs it
945and then root-aligns it it would have to blur the root background on every
946window move or resize.
947
948Another example is C<load>, which can be quite slow.
949
950In fact, urxvt itself encloses the whole expression in some kind of
951C<keep> block so it only is reevaluated as required.
952
953Putting the blur into a C<keep> block will make sure the blur is only done
954once, while the C<rootalign> is still done each time the window moves.
955
956 rootalign keep { blur 10, root }
957
958This leaves the question of how to force reevaluation of the block,
959in case the root background changes: If expression inside the block
960is sensitive to some event (root background changes, window geometry
961changes), then it will be reevaluated automatically as needed.
962
963=cut
964
965 sub keep(&) {
966 my $id = $_[0]+0;
967
968 local $frame = $self->{frame_cache}{$id} ||= [$frame];
969
970 unless ($frame->[FR_CACHE]) {
971 $frame->[FR_CACHE] = [ $_[0]() ];
972
973 my $self = $self;
974 my $frame = $frame;
975 Scalar::Util::weaken $frame;
976 $self->compile_frame ($frame, sub {
977 # clear this frame cache, also for all parents
978 for (my $frame = $frame; $frame; $frame = $frame->[0]) {
979 undef $frame->[FR_CACHE];
980 }
981
982 $self->recalculate;
983 });
984 };
985
986 # in scalar context we always return the first original result, which
987 # is not quite how perl works.
988 wantarray
989 ? @{ $frame->[FR_CACHE] }
990 : $frame->[FR_CACHE][0]
991 }
992
993# sub keep_clear() {
994# delete $self->{frame_cache};
995# }
996
997=back
998
640=cut 999=cut
641 1000
642} 1001}
643 1002
644sub parse_expr { 1003sub parse_expr {
645 my $expr = eval "sub {\npackage urxvt::bgdsl;\n#line 0 'background expression'\n$_[0]\n}"; 1004 my $expr = eval
1005 "sub {\n"
1006 . "package urxvt::bgdsl;\n"
1007 . "#line 0 'background expression'\n"
1008 . "$_[0]\n"
1009 . "}";
646 die if $@; 1010 die if $@;
647 $expr 1011 $expr
648} 1012}
649 1013
650# compiles a parsed expression 1014# compiles a parsed expression
651sub set_expr { 1015sub set_expr {
652 my ($self, $expr) = @_; 1016 my ($self, $expr) = @_;
653 1017
1018 $self->{root} = []; # the outermost frame
654 $self->{expr} = $expr; 1019 $self->{expr} = $expr;
655 $self->recalculate; 1020 $self->recalculate;
1021}
1022
1023# takes a hash of sensitivity indicators and installs watchers
1024sub compile_frame {
1025 my ($self, $frame, $cb) = @_;
1026
1027 my $state = $frame->[urxvt::bgdsl::FR_STATE] ||= {};
1028 my $again = $frame->[urxvt::bgdsl::FR_AGAIN];
1029
1030 # don't keep stuff alive
1031 Scalar::Util::weaken $state;
1032
1033 if ($again->{nested}) {
1034 $state->{nested} = 1;
1035 } else {
1036 delete $state->{nested};
1037 }
1038
1039 if (my $interval = $again->{time}) {
1040 $state->{time} = [$interval, urxvt::timer->new->after ($interval)->interval ($interval)]
1041 if $state->{time}[0] != $interval;
1042
1043 # callback *might* have changed, although we could just rule that out
1044 $state->{time}[1]->cb (sub {
1045 ++$state->{counter};
1046 $cb->();
1047 });
1048 } else {
1049 delete $state->{time};
1050 }
1051
1052 if ($again->{position}) {
1053 $state->{position} = $self->on (position_change => $cb);
1054 } else {
1055 delete $state->{position};
1056 }
1057
1058 if ($again->{size}) {
1059 $state->{size} = $self->on (size_change => $cb);
1060 } else {
1061 delete $state->{size};
1062 }
1063
1064 if ($again->{rootpmap}) {
1065 $state->{rootpmap} = $self->on (rootpmap_change => $cb);
1066 } else {
1067 delete $state->{rootpmap};
1068 }
656} 1069}
657 1070
658# evaluate the current bg expression 1071# evaluate the current bg expression
659sub recalculate { 1072sub recalculate {
660 my ($arg_self) = @_; 1073 my ($arg_self) = @_;
670 1083
671 $arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL; 1084 $arg_self->{next_refresh} = urxvt::NOW + $MIN_INTERVAL;
672 1085
673 # set environment to evaluate user expression 1086 # set environment to evaluate user expression
674 1087
675 local $self = $arg_self; 1088 local $self = $arg_self;
676
677 local $HOME = $ENV{HOME}; 1089 local $HOME = $ENV{HOME};
678 local $old = $self->{state}; 1090 local $frame = $self->{root};
679 local $new = my $state = $self->{state} = {};
680 1091
681 ($x, $y, $w, $h) =
682 $self->background_geometry ($self->{border}); 1092 ($x, $y, $w, $h) = $self->background_geometry ($self->{border});
683 1093
684 # evaluate user expression 1094 # evaluate user expression
685 1095
686 my $img = eval { $self->{expr}->() }; 1096 my @img = eval { $self->{expr}->() };
687 warn $@ if $@;#d# 1097 die $@ if $@;
1098 die "background-expr did not return anything.\n" unless @img;
1099 die "background-expr: expected image(s), got something else.\n"
688 die if !UNIVERSAL::isa $img, "urxvt::img"; 1100 if grep { !UNIVERSAL::isa $_, "urxvt::img" } @img;
689 1101
690 $state->{size_sensitive} = 1 1102 my $img = urxvt::bgdsl::merge @img;
1103
1104 $frame->[FR_AGAIN]{size} = 1
691 if $img->repeat_mode != urxvt::RepeatNormal; 1105 if $img->repeat_mode != urxvt::RepeatNormal;
692 1106
693 # if the expression is sensitive to external events, prepare reevaluation then 1107 # if the expression is sensitive to external events, prepare reevaluation then
694 1108 $self->compile_frame ($frame, sub { $arg_self->recalculate });
695 my $repeat;
696
697 if (my $again = $state->{again}) {
698 $repeat = 1;
699 my $self = $self;
700 $state->{timer} = $again == $old->{again}
701 ? $old->{timer}
702 : urxvt::timer->new->after ($again)->interval ($again)->cb (sub {
703 ++$self->{counter};
704 $self->recalculate
705 });
706 }
707
708 if (delete $state->{position_sensitive}) {
709 $repeat = 1;
710 $self->enable (position_change => sub { $_[0]->recalculate });
711 } else {
712 $self->disable ("position_change");
713 }
714
715 if (delete $state->{size_sensitive}) {
716 $repeat = 1;
717 $self->enable (size_change => sub { $_[0]->recalculate });
718 } else {
719 $self->disable ("size_change");
720 }
721
722 if (delete $state->{rootpmap_sensitive}) {
723 $repeat = 1;
724 $self->enable (rootpmap_change => sub { $_[0]->recalculate });
725 } else {
726 $self->disable ("rootpmap_change");
727 }
728 1109
729 # clear stuff we no longer need 1110 # clear stuff we no longer need
730 1111
731 %$old = (); 1112# unless (%{ $frame->[FR_STATE] }) {
732
733 unless ($repeat) {
734 delete $self->{state}; 1113# delete $self->{state};
735 delete $self->{expr}; 1114# delete $self->{expr};
736 } 1115# }
737 1116
738 # set background pixmap 1117 # set background pixmap
739 1118
740 $self->set_background ($img, $self->{border}); 1119 $self->set_background ($img, $self->{border});
741 $self->scr_recolour (0); 1120 $self->scr_recolour (0);
743} 1122}
744 1123
745sub on_start { 1124sub on_start {
746 my ($self) = @_; 1125 my ($self) = @_;
747 1126
748 my $expr = $self->x_resource ("background.expr") 1127 my $expr = $self->x_resource ("%.expr")
749 or return; 1128 or return;
750 1129
1130 $self->has_render
1131 or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
1132
751 $self->set_expr (parse_expr $expr); 1133 $self->set_expr (parse_expr $expr);
752 $self->{border} = $self->x_resource_boolean ("background.border"); 1134 $self->{border} = $self->x_resource_boolean ("%.border");
1135
1136 $MIN_INTERVAL = $self->x_resource ("%.interval");
753 1137
754 () 1138 ()
755} 1139}
756 1140

Diff Legend

Removed lines
+ Added lines
< Changed lines
> Changed lines