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Revision 1.36 by root, Fri Jun 8 20:23:09 2012 UTC vs.
Revision 1.51 by sf-exg, Sun Jun 10 19:01:03 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
17This extension manages the terminal background by creating a picture that 19This extension manages the terminal background by creating a picture that
18is behind the text, replacing the normal background colour. 20is behind the text, replacing the normal background colour.
19 21
20It does so by evaluating a Perl expression that I<calculates> the image on 22It does so by evaluating a Perl expression that I<calculates> the image on
… …
30 32
31Or specified as a X resource: 33Or 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
37At startup, just before the window is mapped for the first time, the 39At startup, just before the window is mapped for the first time, the
38expression is evaluated and must yield an image. The image is then 40expression 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 41extended as necessary to cover the whole terminal window, and is set as a
40background pixmap. 42background pixmap.
… …
55 57
56For example, an expression such as C<scale load "$HOME/mybg.png"> scales the 58For example, an expression such as C<scale load "$HOME/mybg.png"> scales the
57image to the window size, so it relies on the window size and will 59image to the window size, so it relies on the window size and will
58be reevaluated each time it is changed, but not when it moves for 60be reevaluated each time it is changed, but not when it moves for
59example. That ensures that the picture always fills the terminal, even 61example. That ensures that the picture always fills the terminal, even
60after it's size changes. 62after its size changes.
61 63
62=head3 EXPRESSIONS 64=head2 EXPRESSIONS
63 65
64Expressions are normal Perl expressions, in fact, they are Perl blocks - 66Expressions are normal Perl expressions, in fact, they are Perl blocks -
65which means you could use multiple lines and statements: 67which means you could use multiple lines and statements:
66 68
67 again 3600; 69 again 3600;
… …
70 } else { 72 } else {
71 return scale load "$HOME/sunday.png"; 73 return scale load "$HOME/sunday.png";
72 } 74 }
73 75
74This expression gets evaluated once per hour. It will set F<sunday.png> as 76This expression gets evaluated once per hour. It will set F<sunday.png> as
75background on sundays, and F<weekday.png> on all other days. 77background on Sundays, and F<weekday.png> on all other days.
76 78
77Fortunately, we expect that most expressions will be much simpler, with 79Fortunately, we expect that most expressions will be much simpler, with
78little Perl knowledge needed. 80little Perl knowledge needed.
79 81
80Basically, you always start with a function that "generates" an image 82Basically, you always start with a function that "generates" an image
… …
97its result becomes the argument to the C<scale> function. 99its result becomes the argument to the C<scale> function.
98 100
99Many operators also allow some parameters preceding the input image 101Many operators also allow some parameters preceding the input image
100that modify its behaviour. For example, C<scale> without any additional 102that modify its behaviour. For example, C<scale> without any additional
101arguments scales the image to size of the terminal window. If you specify 103arguments scales the image to size of the terminal window. If you specify
102an additional argument, it uses it as a percentage: 104an additional argument, it uses it as a scale factor (multiply by 100 to
105get a percentage):
103 106
104 scale 200, load "$HOME/mypic.png" 107 scale 2, load "$HOME/mypic.png"
105 108
106This enlarges the image by a factor of 2 (200%). As you can see, C<scale> 109This 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 110has 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 111C<load> only has one argument. Arguments are separated from each other by
109commas. 112commas.
110 113
111Scale also accepts two arguments, which are then separate factors for both 114Scale also accepts two arguments, which are then separate factors for both
112horizontal and vertical dimensions. For example, this halves the image 115horizontal and vertical dimensions. For example, this halves the image
113width and doubles the image height: 116width 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
117TODO 120Other effects than scaling are also readily available, for example, you can
121tile the image to fill the whole window, instead of resizing it:
118 122
123 tile load "$HOME/mypic.png"
124
125In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator
126is kind of superfluous.
127
128Another common effect is to mirror the image, so that the same edges touch:
129
130 mirror load "$HOME/mypic.png"
131
132This is also a typical background expression:
133
134 rootalign root
135
136It first takes a snapshot of the screen background image, and then
137moves it to the upper left corner of the screen - the result is
138pseudo-transparency, as the image seems to be static while the window is
139moved around.
140
119=head3 CYCLES AND CACHING 141=head2 CYCLES AND CACHING
120 142
121TODO 143As has been mentioned before, the expression might be evaluated multiple
122
123Each time the expression is reevaluated, a new cycle is said to have begun. Many operators 144times. Each time the expression is reevaluated, a new cycle is said to
124cache their results till the next cycle. For example 145have begun. Many operators cache their results till the next cycle.
125 146
147For example, the C<load> operator keeps a copy of the image. If it is
148asked to load the same image on the next cycle it will not load it again,
149but return the cached copy.
150
151This only works for one cycle though, so as long as you load the same
152image every time, it will always be cached, but when you load a different
153image, it will forget about the first one.
154
155This allows you to either speed things up by keeping multiple images in
156memory, or conserve memory by loading images more often.
157
158For example, you can keep two images in memory and use a random one like
159this:
160
161 my $img1 = load "img1.png";
162 my $img2 = load "img2.png";
163 (0.5 > rand) ? $img1 : $img2
164
165Since both images are "loaded" every time the expression is evaluated,
166they 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
172Here, a path is selected randomly, and load is only called for one image,
173so keeps only one image in memory. If, on the next evaluation, luck
174decides 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
… …
139overwriting borders and any other areas, such as the scrollbar. 189overwriting borders and any other areas, such as the scrollbar.
140 190
141Specifying this flag changes the behaviour, so that the image only 191Specifying this flag changes the behaviour, so that the image only
142replaces the background of the character area. 192replaces the background of the character area.
143 193
194=item --background-interval seconds
195
196Since some operations in the underlying XRender extension can effectively
197freeze your X-server for prolonged time, this extension enforces a minimum
198time between updates, which is normally about 0.1 seconds.
199
200If you want to do updates more often, you can decrease this safety
201interval with this switch.
202
144=back 203=back
145 204
146=cut 205=cut
147 206
148our $EXPR;#d# 207our %_IMGCACHE;
149#$EXPR = 'move W * 0.1, -H * 0.1, resize W * 0.5, H * 0.5, repeat_none load "opensource.png"';
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
161our $HOME; 208our $HOME;
162our ($self, $old, $new); 209our ($self, $old, $new);
163our ($x, $y, $w, $h); 210our ($x, $y, $w, $h);
164 211
165# enforce at least this interval between updates 212# enforce at least this interval between updates
166our $MIN_INTERVAL = 1/100; 213our $MIN_INTERVAL = 6/59.951;
167 214
168{ 215{
169 package urxvt::bgdsl; # background language 216 package urxvt::bgdsl; # background language
217
218 use List::Util qw(min max sum shuffle);
170 219
171=head2 PROVIDERS/GENERATORS 220=head2 PROVIDERS/GENERATORS
172 221
173These functions provide an image, by loading it from disk, grabbing it 222These functions provide an image, by loading it from disk, grabbing it
174from the root screen or by simply generating it. They are used as starting 223from the root screen or by simply generating it. They are used as starting
… …
211=item solid $width, $height, $colour 260=item solid $width, $height, $colour
212 261
213Creates a new image and completely fills it with the given colour. The 262Creates a new image and completely fills it with the given colour. The
214image is set to tiling mode. 263image is set to tiling mode.
215 264
216If <$width> and C<$height> are omitted, it creates a 1x1 image, which is 265If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
217useful for solid backgrounds or for use in filtering effects. 266useful for solid backgrounds or for use in filtering effects.
218 267
219=cut 268=cut
220 269
221 sub solid($$;$) { 270 sub solid($;$$) {
222 my $colour = pop; 271 my $colour = pop;
223 272
224 my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] || 1, $_[1] || 1); 273 my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] || 1, $_[1] || 1);
225 $img->fill ($colour); 274 $img->fill ($colour);
226 $img 275 $img
227 } 276 }
228 277
278=item clone $img
279
280Returns an exact copy of the image. This is useful if you want to have
281multiple copies of the same image to apply different effects to.
282
283=cut
284
285 sub clone($) {
286 $_[0]->clone
287 }
288
229=back 289=back
230 290
291=head2 TILING MODES
292
293The following operators modify the tiling mode of an image, that is, the
294way that pixels outside the image area are painted when the image is used.
295
296=over 4
297
298=item tile $img
299
300Tiles the whole plane with the image and returns this new image - or in
301other words, it returns a copy of the image in plane tiling mode.
302
303Example: load an image and tile it over the background, without
304resizing. The C<tile> call is superfluous because C<load> already defaults
305to tiling mode.
306
307 tile load "mybg.png"
308
309=item mirror $img
310
311Similar to tile, but reflects the image each time it uses a new copy, so
312that top edges always touch top edges, right edges always touch right
313edges and so on (with normal tiling, left edges always touch right edges
314and top always touch bottom edges).
315
316Example: load an image and mirror it over the background, avoiding sharp
317edges at the image borders at the expense of mirroring the image itself
318
319 mirror load "mybg.png"
320
321=item pad $img
322
323Takes an image and modifies it so that all pixels outside the image area
324become transparent. This mode is most useful when you want to place an
325image over another image or the background colour while leaving all
326background pixels outside the image unchanged.
327
328Example: load an image and display it in the upper left corner. The rest
329of the space is left "empty" (transparent or whatever your compositor does
330in alpha mode, else background colour).
331
332 pad load "mybg.png"
333
334=item extend $img
335
336Extends the image over the whole plane, using the closest pixel in the
337area outside the image. This mode is mostly useful when you use more complex
338filtering operations and want the pixels outside the image to have the
339same values as the pixels near the edge.
340
341Example: just for curiosity, how does this pixel extension stuff work?
342
343 extend move 50, 50, load "mybg.png"
344
345=cut
346
347 sub pad($) {
348 my $img = $_[0]->clone;
349 $img->repeat_mode (urxvt::RepeatNone);
350 $img
351 }
352
353 sub tile($) {
354 my $img = $_[0]->clone;
355 $img->repeat_mode (urxvt::RepeatNormal);
356 $img
357 }
358
359 sub mirror($) {
360 my $img = $_[0]->clone;
361 $img->repeat_mode (urxvt::RepeatReflect);
362 $img
363 }
364
365 sub extend($) {
366 my $img = $_[0]->clone;
367 $img->repeat_mode (urxvt::RepeatPad);
368 $img
369 }
370
371=back
372
231=head2 VARIABLES 373=head2 VARIABLE VALUES
232 374
233The following functions provide variable data such as the terminal 375The following functions provide variable data such as the terminal window
376dimensions. They are not (Perl-) variables, they just return stuff that
234window dimensions. Most of them make your expression sensitive to some 377varies. Most of them make your expression sensitive to some events, for
235events, for example using C<TW> (terminal width) means your expression is 378example using C<TW> (terminal width) means your expression is evaluated
236evaluated again when the terminal is resized. 379again when the terminal is resized.
237 380
238=over 4 381=over 4
239 382
240=item TX 383=item TX
241 384
… …
312 $self->{counter} + 0 455 $self->{counter} + 0
313 } 456 }
314 457
315=back 458=back
316 459
317=head2 TILING MODES 460=head2 SHAPE CHANGING OPERATORS
318 461
319The following operators modify the tiling mode of an image, that is, the 462The following operators modify the shape, size or position of the image.
320way that pixels outside the image area are painted when the image is used.
321 463
322=over 4 464=over 4
323
324=item tile $img
325
326Tiles the whole plane with the image and returns this new image - or in
327other words, it returns a copy of the image in plane tiling mode.
328
329Example: load an image and tile it over the background, without
330resizing. The C<tile> call is superfluous because C<load> already defaults
331to tiling mode.
332
333 tile load "mybg.png"
334
335=item mirror $img
336
337Similar to tile, but reflects the image each time it uses a new copy, so
338that top edges always touch top edges, right edges always touch right
339edges and so on (with normal tiling, left edges always touch right edges
340and top always touch bottom edges).
341
342Example: load an image and mirror it over the background, avoiding sharp
343edges at the image borders at the expense of mirroring the image itself
344
345 mirror load "mybg.png"
346
347=item pad $img
348
349Takes an image and modifies it so that all pixels outside the image area
350become transparent. This mode is most useful when you want to place an
351image over another image or the background colour while leaving all
352background pixels outside the image unchanged.
353
354Example: load an image and display it in the upper left corner. The rest
355of the space is left "empty" (transparent or wahtever your compisotr does
356in alpha mode, else background colour).
357
358 pad load "mybg.png"
359
360=item extend $img
361
362Extends the image over the whole plane, using the closest pixel in the
363area outside the image. This mode is mostly useful when you more complex
364filtering operations and want the pixels outside the image to have the
365same values as the pixels near the edge.
366
367Example: just for curiosity, how does this pixel extension stuff work?
368
369 extend move 50, 50, load "mybg.png"
370
371=cut
372
373 sub pad($) {
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
401The following operators modify the image pixels in various ways.
402
403=over 4
404
405=item clone $img
406
407Returns an exact copy of the image.
408
409=cut
410
411 sub clone($) {
412 $_[0]->clone
413 }
414 465
415=item clip $img 466=item clip $img
416 467
417=item clip $width, $height, $img 468=item clip $width, $height, $img
418 469
… …
442 $img->sub_rect ($_[0], $_[1], $w, $h) 493 $img->sub_rect ($_[0], $_[1], $w, $h)
443 } 494 }
444 495
445=item scale $img 496=item scale $img
446 497
447=item scale $size_percent, $img 498=item scale $size_factor, $img
448 499
449=item scale $width_percent, $height_percent, $img 500=item scale $width_factor, $height_factor, $img
450 501
451Scales the image by the given percentages in horizontal 502Scales the image by the given factors in horizontal
452(C<$width_percent>) and vertical (C<$height_percent>) direction. 503(C<$width>) and vertical (C<$height>) direction.
453 504
454If only one percentage is give, it is used for both directions. 505If only one factor is give, it is used for both directions.
455 506
456If no percentages are given, scales the image to the window size without 507If no factors are given, scales the image to the window size without
457keeping aspect. 508keeping aspect.
458 509
459=item resize $width, $height, $img 510=item resize $width, $height, $img
460 511
461Resizes the image to exactly C<$width> times C<$height> pixels. 512Resizes the image to exactly C<$width> times C<$height> pixels.
462 513
463=cut 514=item fit $img
464 515
465#TODO: maximise, maximise_fill? 516=item fit $width, $height, $img
517
518Fits the image into the given C<$width> and C<$height> without changing
519aspect, or the terminal size. That means it will be shrunk or grown until
520the whole image fits into the given area, possibly leaving borders.
521
522=item cover $img
523
524=item cover $width, $height, $img
525
526Similar to C<fit>, but shrinks or grows until all of the area is covered
527by the image, so instead of potentially leaving borders, it will cut off
528image data that doesn't fit.
529
530=cut
466 531
467 sub scale($;$;$) { 532 sub scale($;$;$) {
468 my $img = pop; 533 my $img = pop;
469 534
470 @_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01) 535 @_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
471 : @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01) 536 : @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
472 : $img->scale (TW, TH) 537 : $img->scale (TW, TH)
473 } 538 }
474 539
475 sub resize($$$) { 540 sub resize($$$) {
476 my $img = pop; 541 my $img = pop;
477 $img->scale ($_[0], $_[1]) 542 $img->scale ($_[0], $_[1])
543 }
544
545 sub fit($;$$) {
546 my $img = pop;
547 my $w = ($_[0] || TW) / $img->w;
548 my $h = ($_[1] || TH) / $img->h;
549 scale +(min $w, $h), $img
550 }
551
552 sub cover($;$$) {
553 my $img = pop;
554 my $w = ($_[0] || TW) / $img->w;
555 my $h = ($_[1] || TH) / $img->h;
556 scale +(max $w, $h), $img
478 } 557 }
479 558
480=item move $dx, $dy, $img 559=item move $dx, $dy, $img
481 560
482Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in 561Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
483the vertical. 562the vertical.
484 563
485Example: move the image right by 20 pixels and down by 30. 564Example: move the image right by 20 pixels and down by 30.
486 565
487 move 20, 30, ... 566 move 20, 30, ...
567
568=item align $xalign, $yalign, $img
569
570Aligns the image according to a factor - C<0> means the image is moved to
571the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
572exactly centered and C<1> means it touches the right or bottom edge.
573
574Example: remove any visible border around an image, center it vertically but move
575it to the right hand side.
576
577 align 1, 0.5, pad $img
578
579=item center $img
580
581=item center $width, $height, $img
582
583Centers the image, i.e. the center of the image is moved to the center of
584the terminal window (or the box specified by C<$width> and C<$height> if
585given).
586
587Example: load an image and center it.
588
589 center pad load "mybg.png"
488 590
489=item rootalign $img 591=item rootalign $img
490 592
491Moves the image so that it appears glued to the screen as opposed to the 593Moves the image so that it appears glued to the screen as opposed to the
492window. This gives the illusion of a larger area behind the window. It is 594window. This gives the illusion of a larger area behind the window. It is
… …
498 rootalign mirror load "mybg.png" 600 rootalign mirror load "mybg.png"
499 601
500Example: take the screen background and align it, giving the illusion of 602Example: take the screen background and align it, giving the illusion of
501transparency as long as the window isn't in front of other windows. 603transparency as long as the window isn't in front of other windows.
502 604
503 rootalign root 605 rootalign root
504 606
505=cut 607=cut
506 608
507 sub move($$;$) { 609 sub move($$;$) {
508 my $img = pop->clone; 610 my $img = pop->clone;
509 $img->move ($_[0], $_[1]); 611 $img->move ($_[0], $_[1]);
510 $img 612 $img
511 } 613 }
512 614
615 sub align($;$$) {
616 my $img = pop;
617
618 move $_[0] * (TW - $img->w),
619 $_[1] * (TH - $img->h),
620 $img
621 }
622
623 sub center($;$$) {
624 my $img = pop;
625 my $w = $_[0] || TW;
626 my $h = $_[1] || TH;
627
628 move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
629 }
630
513 sub rootalign($) { 631 sub rootalign($) {
514 move -TX, -TY, $_[0] 632 move -TX, -TY, $_[0]
515 } 633 }
516 634
635=back
636
637=head2 COLOUR MODIFICATIONS
638
639The following operators change the pixels of the image.
640
641=over 4
642
517=item contrast $factor, $img 643=item contrast $factor, $img
518 644
519=item contrast $r, $g, $b, $img 645=item contrast $r, $g, $b, $img
520 646
521=item contrast $r, $g, $b, $a, $img 647=item contrast $r, $g, $b, $a, $img
522 648
523Adjusts the I<contrast> of an image. 649Adjusts the I<contrast> of an image.
524 650
651The first form applies a single C<$factor> to red, green and blue, the
652second form applies separate factors to each colour channel, and the last
653form includes the alpha channel.
654
655Values from 0 to 1 lower the contrast, values higher than 1 increase the
656contrast.
657
658Due to limitations in the underlying XRender extension, lowering contrast
659also reduces brightness, while increasing contrast currently also
660increases brightness.
661
525=item brightness $factor, $img 662=item brightness $bias, $img
526 663
527=item brightness $r, $g, $b, $img 664=item brightness $r, $g, $b, $img
528 665
529=item brightness $r, $g, $b, $a, $img 666=item brightness $r, $g, $b, $a, $img
530 667
668Adjusts the brightness of an image.
669
670The first form applies a single C<$bias> to red, green and blue, the
671second form applies separate biases to each colour channel, and the last
672form includes the alpha channel.
673
674Values less than 0 reduce brightness, while values larger than 0 increase
675it. Useful range is from -1 to 1 - the former results in a black, the
676latter in a white picture.
677
678Due to idiosyncrasies in the underlying XRender extension, biases less
679than zero can be I<very> slow.
680
531=cut 681=cut
532 682
533 sub contrast($$;$$;$) { 683 sub contrast($$;$$;$) {
534 my $img = pop; 684 my $img = pop;
535 my ($r, $g, $b, $a) = @_; 685 my ($r, $g, $b, $a) = @_;
536 686
537 ($g, $b) = ($r, $r) if @_ < 4; 687 ($g, $b) = ($r, $r) if @_ < 3;
538 $a = 1 if @_ < 5; 688 $a = 1 if @_ < 4;
539 689
540 $img = $img->clone; 690 $img = $img->clone;
541# $img->contrast ($r, $g, $b, $a); 691 $img->contrast ($r, $g, $b, $a);
542 $img 692 $img
543 } 693 }
544 694
545 sub brightness($$;$$;$) { 695 sub brightness($$;$$;$) {
546 my $img = pop; 696 my $img = pop;
547 my ($r, $g, $b, $a) = @_; 697 my ($r, $g, $b, $a) = @_;
548 698
549 ($g, $b) = ($r, $r) if @_ < 4; 699 ($g, $b) = ($r, $r) if @_ < 3;
550 $a = 1 if @_ < 5; 700 $a = 1 if @_ < 4;
551 701
552 $img = $img->clone; 702 $img = $img->clone;
553 $img->brightness ($r, $g, $b, $a); 703 $img->brightness ($r, $g, $b, $a);
554 $img 704 $img
555 } 705 }
556 706
707=item blur $radius, $img
708
709=item blur $radius_horz, $radius_vert, $img
710
711Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
712can also be specified separately.
713
714Blurring is often I<very> slow, at least compared or other
715operators. Larger blur radii are slower than smaller ones, too, so if you
716don't want to freeze your screen for long times, start experimenting with
717low values for radius (<5).
718
719=cut
720
557 sub blur($$;$) { 721 sub blur($$;$) {
558 my $img = pop; 722 my $img = pop;
559 $img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0]) 723 $img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
560 } 724 }
725
726=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
727
728Rotates the image by C<$degrees> degrees, counter-clockwise, around the
729pointer at C<$center_x> and C<$center_y> (specified as factor of image
730width/height), generating a new image with width C<$new_width> and height
731C<$new_height>.
732
733#TODO# new width, height, maybe more operators?
734
735Example: rotate the image by 90 degrees
736
737=cut
561 738
562 sub rotate($$$$$$) { 739 sub rotate($$$$$$) {
563 my $img = pop; 740 my $img = pop;
564 $img->rotate ( 741 $img->rotate (
565 $_[0], 742 $_[0],
566 $_[1], 743 $_[1],
567 $_[2] * $img->w * .01, 744 $_[2] * $img->w,
568 $_[3] * $img->h * .01, 745 $_[3] * $img->h,
569 $_[4] * (3.14159265 / 180), 746 $_[4] * (3.14159265 / 180),
570 ) 747 )
571 } 748 }
572 749
573=back 750=back
… …
618 795
619 # evaluate user expression 796 # evaluate user expression
620 797
621 my $img = eval { $self->{expr}->() }; 798 my $img = eval { $self->{expr}->() };
622 warn $@ if $@;#d# 799 warn $@ if $@;#d#
623 die if !UNIVERSAL::isa $img, "urxvt::img"; 800 die "background-expr did not return an image.\n" if !UNIVERSAL::isa $img, "urxvt::img";
624 801
625 $state->{size_sensitive} = 1 802 $state->{size_sensitive} = 1
626 if $img->repeat_mode != urxvt::RepeatNormal; 803 if $img->repeat_mode != urxvt::RepeatNormal;
627 804
628 # if the expression is sensitive to external events, prepare reevaluation then 805 # if the expression is sensitive to external events, prepare reevaluation then
… …
678} 855}
679 856
680sub on_start { 857sub on_start {
681 my ($self) = @_; 858 my ($self) = @_;
682 859
683 my $expr = $self->x_resource ("background.expr") 860 my $expr = $self->x_resource ("%.expr")
684 or return; 861 or return;
685 862
863 $self->has_render
864 or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
865
686 $self->set_expr (parse_expr $expr); 866 $self->set_expr (parse_expr $expr);
687 $self->{border} = $self->x_resource_boolean ("background.border"); 867 $self->{border} = $self->x_resource_boolean ("%.border");
868
869 $MIN_INTERVAL = $self->x_resource ("%.interval");
688 870
689 () 871 ()
690} 872}
691 873

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