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Revision 1.36 by root, Fri Jun 8 20:23:09 2012 UTC vs.
Revision 1.47 by root, Sun Jun 10 13:58:05 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#TODO: once, rootalign
7 8
9=head1 NAME
10
8=head1 background - manage terminal background 11 background - manage terminal background
9 12
10=head2 SYNOPSIS 13=head1 SYNOPSIS
11 14
12 urxvt --background-expr 'background expression' 15 urxvt --background-expr 'background expression'
13 --background-border 16 --background-border
17 --background-interval seconds
14 18
15=head2 DESCRIPTION 19=head1 DESCRIPTION
16 20
17This extension manages the terminal background by creating a picture that 21This extension manages the terminal background by creating a picture that
18is behind the text, replacing the normal background colour. 22is behind the text, replacing the normal background colour.
19 23
20It does so by evaluating a Perl expression that I<calculates> the image on 24It does so by evaluating a Perl expression that I<calculates> the image on
… …
30 34
31Or specified as a X resource: 35Or specified as a X resource:
32 36
33 URxvt.background-expr: scale load "/path/to/mybg.png" 37 URxvt.background-expr: scale load "/path/to/mybg.png"
34 38
35=head2 THEORY OF OPERATION 39=head1 THEORY OF OPERATION
36 40
37At startup, just before the window is mapped for the first time, the 41At startup, just before the window is mapped for the first time, the
38expression is evaluated and must yield an image. The image is then 42expression 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 43extended as necessary to cover the whole terminal window, and is set as a
40background pixmap. 44background pixmap.
… …
57image to the window size, so it relies on the window size and will 61image 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 62be reevaluated each time it is changed, but not when it moves for
59example. That ensures that the picture always fills the terminal, even 63example. That ensures that the picture always fills the terminal, even
60after it's size changes. 64after it's size changes.
61 65
62=head3 EXPRESSIONS 66=head2 EXPRESSIONS
63 67
64Expressions are normal Perl expressions, in fact, they are Perl blocks - 68Expressions are normal Perl expressions, in fact, they are Perl blocks -
65which means you could use multiple lines and statements: 69which means you could use multiple lines and statements:
66 70
67 again 3600; 71 again 3600;
… …
70 } else { 74 } else {
71 return scale load "$HOME/sunday.png"; 75 return scale load "$HOME/sunday.png";
72 } 76 }
73 77
74This expression gets evaluated once per hour. It will set F<sunday.png> as 78This expression gets evaluated once per hour. It will set F<sunday.png> as
75background on sundays, and F<weekday.png> on all other days. 79background on Sundays, and F<weekday.png> on all other days.
76 80
77Fortunately, we expect that most expressions will be much simpler, with 81Fortunately, we expect that most expressions will be much simpler, with
78little Perl knowledge needed. 82little Perl knowledge needed.
79 83
80Basically, you always start with a function that "generates" an image 84Basically, you always start with a function that "generates" an image
… …
97its result becomes the argument to the C<scale> function. 101its result becomes the argument to the C<scale> function.
98 102
99Many operators also allow some parameters preceding the input image 103Many operators also allow some parameters preceding the input image
100that modify its behaviour. For example, C<scale> without any additional 104that modify its behaviour. For example, C<scale> without any additional
101arguments scales the image to size of the terminal window. If you specify 105arguments scales the image to size of the terminal window. If you specify
102an additional argument, it uses it as a percentage: 106an additional argument, it uses it as a scale factor (multiply by 100 to
107get a percentage):
103 108
104 scale 200, load "$HOME/mypic.png" 109 scale 2, load "$HOME/mypic.png"
105 110
106This enlarges the image by a factor of 2 (200%). As you can see, C<scale> 111This 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 112has 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 113C<load> only has one argument. Arguments are separated from each other by
109commas. 114commas.
110 115
111Scale also accepts two arguments, which are then separate factors for both 116Scale also accepts two arguments, which are then separate factors for both
112horizontal and vertical dimensions. For example, this halves the image 117horizontal and vertical dimensions. For example, this halves the image
113width and doubles the image height: 118width and doubles the image height:
114 119
115 scale 50, 200, load "$HOME/mypic.png" 120 scale 0.5, 2, load "$HOME/mypic.png"
116 121
117TODO 122Other effects than scalign are also readily available, for exmaple, you can
123tile the image to fill the whole window, instead of resizing it:
118 124
125 tile load "$HOME/mypic.png"
126
127In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator
128is kind of superfluous.
129
130Another common effect is to mirror the image, so that the same edges touch:
131
132 mirror load "$HOME/mypic.png"
133
134This is also a typical background expression:
135
136 rootalign root
137
138It first takes a snapshot of the screen background image, and then
139moves it to the upper left corner of the screen - the result is
140pseudo-transparency, as the image seems to be static while the window is
141moved around.
142
119=head3 CYCLES AND CACHING 143=head2 CYCLES AND CACHING
120 144
121TODO 145As 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 146times. Each time the expression is reevaluated, a new cycle is said to
124cache their results till the next cycle. For example 147have begun. Many operators cache their results till the next cycle.
125 148
149For example, the C<load> operator keeps a copy of the image. If it is
150asked to load the same image on the next cycle it will not load it again,
151but return the cached copy.
152
153This only works for one cycle though, so as long as you load the same
154image every time, it will always be cached, but when you load a different
155image, it will forget about the first one.
156
157This allows you to either speed things up by keeping multiple images in
158memory, or comserve memory by loading images more often.
159
160For example, you can keep two images in memory and use a random one like
161this:
162
163 my $img1 = load "img1.png";
164 my $img2 = load "img2.png";
165 (0.5 > rand) ? $img1 : $img2
166
167Since both images are "loaded" every time the expression is evaluated,
168they are always kept in memory. Contrast this version:
169
170 my $path1 = "img1.png";
171 my $path2 = "img2.png";
172 load ((0.5 > rand) ? $path1 : $path2)
173
174Here, a path is selected randomly, and load is only called for one image,
175so keeps only one image in memory. If, on the next evaluation, luck
176decides to use the other path, then it will have to load that image again.
177
126=head2 REFERENCE 178=head1 REFERENCE
127 179
128=head3 COMMAND LINE SWITCHES 180=head2 COMMAND LINE SWITCHES
129 181
130=over 4 182=over 4
131 183
132=item --background-expr perl-expression 184=item --background-expr perl-expression
133 185
… …
139overwriting borders and any other areas, such as the scrollbar. 191overwriting borders and any other areas, such as the scrollbar.
140 192
141Specifying this flag changes the behaviour, so that the image only 193Specifying this flag changes the behaviour, so that the image only
142replaces the background of the character area. 194replaces the background of the character area.
143 195
196=item --background-interval seconds
197
198Since some operations in the underlying XRender extension can effetively
199freeze your X-server for prolonged time, this extension enforces a minimum
200time between updates, which is normally about 0.1 seconds.
201
202If you want to do updates more often, you can decrease this safety
203interval with this switch.
204
144=back 205=back
145 206
146=cut 207=cut
147
148our $EXPR;#d#
149#$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
160 208
161our $HOME; 209our $HOME;
162our ($self, $old, $new); 210our ($self, $old, $new);
163our ($x, $y, $w, $h); 211our ($x, $y, $w, $h);
164 212
165# enforce at least this interval between updates 213# enforce at least this interval between updates
166our $MIN_INTERVAL = 1/100; 214our $MIN_INTERVAL = 6/59.951;
167 215
168{ 216{
169 package urxvt::bgdsl; # background language 217 package urxvt::bgdsl; # background language
218
219 use List::Util qw(min max sum shuffle);
170 220
171=head2 PROVIDERS/GENERATORS 221=head2 PROVIDERS/GENERATORS
172 222
173These functions provide an image, by loading it from disk, grabbing it 223These 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 224from the root screen or by simply generating it. They are used as starting
… …
211=item solid $width, $height, $colour 261=item solid $width, $height, $colour
212 262
213Creates a new image and completely fills it with the given colour. The 263Creates a new image and completely fills it with the given colour. The
214image is set to tiling mode. 264image is set to tiling mode.
215 265
216If <$width> and C<$height> are omitted, it creates a 1x1 image, which is 266If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is
217useful for solid backgrounds or for use in filtering effects. 267useful for solid backgrounds or for use in filtering effects.
218 268
219=cut 269=cut
220 270
221 sub solid($$;$) { 271 sub solid($;$$) {
222 my $colour = pop; 272 my $colour = pop;
223 273
224 my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] || 1, $_[1] || 1); 274 my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] || 1, $_[1] || 1);
225 $img->fill ($colour); 275 $img->fill ($colour);
226 $img 276 $img
227 } 277 }
228 278
279=item clone $img
280
281Returns an exact copy of the image. This is useful if you want to have
282multiple copies of the same image to apply different effects to.
283
284=cut
285
286 sub clone($) {
287 $_[0]->clone
288 }
289
229=back 290=back
230 291
292=head2 TILING MODES
293
294The following operators modify the tiling mode of an image, that is, the
295way that pixels outside the image area are painted when the image is used.
296
297=over 4
298
299=item tile $img
300
301Tiles the whole plane with the image and returns this new image - or in
302other words, it returns a copy of the image in plane tiling mode.
303
304Example: load an image and tile it over the background, without
305resizing. The C<tile> call is superfluous because C<load> already defaults
306to tiling mode.
307
308 tile load "mybg.png"
309
310=item mirror $img
311
312Similar to tile, but reflects the image each time it uses a new copy, so
313that top edges always touch top edges, right edges always touch right
314edges and so on (with normal tiling, left edges always touch right edges
315and top always touch bottom edges).
316
317Example: load an image and mirror it over the background, avoiding sharp
318edges at the image borders at the expense of mirroring the image itself
319
320 mirror load "mybg.png"
321
322=item pad $img
323
324Takes an image and modifies it so that all pixels outside the image area
325become transparent. This mode is most useful when you want to place an
326image over another image or the background colour while leaving all
327background pixels outside the image unchanged.
328
329Example: load an image and display it in the upper left corner. The rest
330of the space is left "empty" (transparent or wahtever your compisotr does
331in alpha mode, else background colour).
332
333 pad load "mybg.png"
334
335=item extend $img
336
337Extends the image over the whole plane, using the closest pixel in the
338area outside the image. This mode is mostly useful when you more complex
339filtering operations and want the pixels outside the image to have the
340same values as the pixels near the edge.
341
342Example: just for curiosity, how does this pixel extension stuff work?
343
344 extend move 50, 50, load "mybg.png"
345
346=cut
347
348 sub pad($) {
349 my $img = $_[0]->clone;
350 $img->repeat_mode (urxvt::RepeatNone);
351 $img
352 }
353
354 sub tile($) {
355 my $img = $_[0]->clone;
356 $img->repeat_mode (urxvt::RepeatNormal);
357 $img
358 }
359
360 sub mirror($) {
361 my $img = $_[0]->clone;
362 $img->repeat_mode (urxvt::RepeatReflect);
363 $img
364 }
365
366 sub extend($) {
367 my $img = $_[0]->clone;
368 $img->repeat_mode (urxvt::RepeatPad);
369 $img
370 }
371
372=back
373
231=head2 VARIABLES 374=head2 VARIABLE VALUES
232 375
233The following functions provide variable data such as the terminal 376The following functions provide variable data such as the terminal window
377dimensions. They are not (Perl-) variables, they just return stuff that
234window dimensions. Most of them make your expression sensitive to some 378varies. Most of them make your expression sensitive to some events, for
235events, for example using C<TW> (terminal width) means your expression is 379example using C<TW> (terminal width) means your expression is evaluated
236evaluated again when the terminal is resized. 380again when the terminal is resized.
237 381
238=over 4 382=over 4
239 383
240=item TX 384=item TX
241 385
… …
312 $self->{counter} + 0 456 $self->{counter} + 0
313 } 457 }
314 458
315=back 459=back
316 460
317=head2 TILING MODES 461=head2 SHAPE CHANGING OPERATORS
318 462
319The following operators modify the tiling mode of an image, that is, the 463The 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.
321 464
322=over 4 465=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 }
414 466
415=item clip $img 467=item clip $img
416 468
417=item clip $width, $height, $img 469=item clip $width, $height, $img
418 470
… …
442 $img->sub_rect ($_[0], $_[1], $w, $h) 494 $img->sub_rect ($_[0], $_[1], $w, $h)
443 } 495 }
444 496
445=item scale $img 497=item scale $img
446 498
447=item scale $size_percent, $img 499=item scale $size_factor, $img
448 500
449=item scale $width_percent, $height_percent, $img 501=item scale $width_factor, $height_factor, $img
450 502
451Scales the image by the given percentages in horizontal 503Scales the image by the given factors in horizontal
452(C<$width_percent>) and vertical (C<$height_percent>) direction. 504(C<$width>) and vertical (C<$height>) direction.
453 505
454If only one percentage is give, it is used for both directions. 506If only one factor is give, it is used for both directions.
455 507
456If no percentages are given, scales the image to the window size without 508If no factors are given, scales the image to the window size without
457keeping aspect. 509keeping aspect.
458 510
459=item resize $width, $height, $img 511=item resize $width, $height, $img
460 512
461Resizes the image to exactly C<$width> times C<$height> pixels. 513Resizes the image to exactly C<$width> times C<$height> pixels.
462 514
463=cut 515=item fit $img
464 516
465#TODO: maximise, maximise_fill? 517=item fit $width, $height, $img
518
519Fits the image into the given C<$width> and C<$height> without changing
520aspect, or the terminal size. That means it will be shrunk or grown until
521the whole image fits into the given area, possibly leaving borders.
522
523=item cover $img
524
525=item cover $width, $height, $img
526
527Similar to C<fit>, but shrinks or grows until all of the area is covered
528by the image, so instead of potentially leaving borders, it will cut off
529image data that doesn't fit.
530
531=cut
466 532
467 sub scale($;$;$) { 533 sub scale($;$;$) {
468 my $img = pop; 534 my $img = pop;
469 535
470 @_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01) 536 @_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h)
471 : @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01) 537 : @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h)
472 : $img->scale (TW, TH) 538 : $img->scale (TW, TH)
473 } 539 }
474 540
475 sub resize($$$) { 541 sub resize($$$) {
476 my $img = pop; 542 my $img = pop;
477 $img->scale ($_[0], $_[1]) 543 $img->scale ($_[0], $_[1])
544 }
545
546 sub fit($;$$) {
547 my $img = pop;
548 my $w = ($_[0] || TW) / $img->w;
549 my $h = ($_[1] || TH) / $img->h;
550 scale +(min $w, $h), $img
551 }
552
553 sub cover($;$$) {
554 my $img = pop;
555 my $w = ($_[0] || TW) / $img->w;
556 my $h = ($_[1] || TH) / $img->h;
557 scale +(max $w, $h), $img
478 } 558 }
479 559
480=item move $dx, $dy, $img 560=item move $dx, $dy, $img
481 561
482Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in 562Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in
483the vertical. 563the vertical.
484 564
485Example: move the image right by 20 pixels and down by 30. 565Example: move the image right by 20 pixels and down by 30.
486 566
487 move 20, 30, ... 567 move 20, 30, ...
568
569=item align $xalign, $yalign, $img
570
571Aligns the image according to a factor - C<0> means the image is moved to
572the left or top edge (for C<$xalign> or C<$yalign>), C<0.5> means it is
573exactly centered and C<1> means it touches the right or bottom edge.
574
575Example: remove any visible border around an image, center it vertically but move
576it to the right hand side.
577
578 align 1, 0.5, pad $img
579
580=item center $img
581
582=item center $width, $height, $img
583
584Centers the image, i.e. the center of the image is moved to the center of
585the terminal window (or the box specified by C<$width> and C<$height> if
586given).
587
588Example: load an image and center it.
589
590 center pad load "mybg.png"
488 591
489=item rootalign $img 592=item rootalign $img
490 593
491Moves the image so that it appears glued to the screen as opposed to the 594Moves 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 595window. This gives the illusion of a larger area behind the window. It is
… …
498 rootalign mirror load "mybg.png" 601 rootalign mirror load "mybg.png"
499 602
500Example: take the screen background and align it, giving the illusion of 603Example: take the screen background and align it, giving the illusion of
501transparency as long as the window isn't in front of other windows. 604transparency as long as the window isn't in front of other windows.
502 605
503 rootalign root 606 rootalign root
504 607
505=cut 608=cut
506 609
507 sub move($$;$) { 610 sub move($$;$) {
508 my $img = pop->clone; 611 my $img = pop->clone;
509 $img->move ($_[0], $_[1]); 612 $img->move ($_[0], $_[1]);
510 $img 613 $img
511 } 614 }
512 615
616 sub align($;$$) {
617 my $img = pop;
618
619 move $_[0] * (TW - $img->w),
620 $_[1] * (TH - $img->h),
621 $img
622 }
623
624 sub center($;$$) {
625 my $img = pop;
626 my $w = $_[0] || TW;
627 my $h = $_[1] || TH;
628
629 move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img
630 }
631
513 sub rootalign($) { 632 sub rootalign($) {
514 move -TX, -TY, $_[0] 633 move -TX, -TY, $_[0]
515 } 634 }
516 635
636=back
637
638=head2 COLOUR MODIFICATIONS
639
640The following operators change the pixels of the image.
641
642=over 4
643
517=item contrast $factor, $img 644=item contrast $factor, $img
518 645
519=item contrast $r, $g, $b, $img 646=item contrast $r, $g, $b, $img
520 647
521=item contrast $r, $g, $b, $a, $img 648=item contrast $r, $g, $b, $a, $img
522 649
523Adjusts the I<contrast> of an image. 650Adjusts the I<contrast> of an image.
524 651
652The first form applies a single C<$factor> to red, green and blue, the
653second form applies separate factors to each colour channel, and the last
654form includes the alpha channel.
655
656Values from 0 to 1 lower the contrast, values higher than 1 increase the
657contrast.
658
659Due to limitations in the underlying XRender extension, lowering contrast
660also reduces brightness, while increasing contrast currently also
661increases brightness.
662
525=item brightness $factor, $img 663=item brightness $bias, $img
526 664
527=item brightness $r, $g, $b, $img 665=item brightness $r, $g, $b, $img
528 666
529=item brightness $r, $g, $b, $a, $img 667=item brightness $r, $g, $b, $a, $img
668
669Adjusts the brightness of an image.
670
671The first form applies a single C<$bias> to red, green and blue, the
672second form applies separate biases to each colour channel, and the last
673form includes the alpha channel.
674
675Values less than 0 reduce brightness, while values larger than 0 increase
676it. Useful range is from -1 to 1 - the former results in a black, the
677latter in a white picture.
678
679Due to idiosynchrasies in the underlying XRender extension, biases less
680than zero can be I<very> slow.
530 681
531=cut 682=cut
532 683
533 sub contrast($$;$$;$) { 684 sub contrast($$;$$;$) {
534 my $img = pop; 685 my $img = pop;
… …
536 687
537 ($g, $b) = ($r, $r) if @_ < 4; 688 ($g, $b) = ($r, $r) if @_ < 4;
538 $a = 1 if @_ < 5; 689 $a = 1 if @_ < 5;
539 690
540 $img = $img->clone; 691 $img = $img->clone;
541# $img->contrast ($r, $g, $b, $a); 692 $img->contrast ($r, $g, $b, $a);
542 $img 693 $img
543 } 694 }
544 695
545 sub brightness($$;$$;$) { 696 sub brightness($$;$$;$) {
546 my $img = pop; 697 my $img = pop;
… …
552 $img = $img->clone; 703 $img = $img->clone;
553 $img->brightness ($r, $g, $b, $a); 704 $img->brightness ($r, $g, $b, $a);
554 $img 705 $img
555 } 706 }
556 707
708=item blur $radius, $img
709
710=item blur $radius_horz, $radius_vert, $img
711
712Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii
713can also be specified separately.
714
715Blurring is often I<very> slow, at least compared or other
716operators. Larger blur radii are slower than smaller ones, too, so if you
717don't want to freeze your screen for long times, start experimenting with
718low values for radius (<5).
719
720=cut
721
557 sub blur($$;$) { 722 sub blur($$;$) {
558 my $img = pop; 723 my $img = pop;
559 $img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0]) 724 $img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0])
560 } 725 }
726
727=item rotate $new_width, $new_height, $center_x, $center_y, $degrees
728
729Rotates the image by C<$degrees> degrees, counter-clockwise, around the
730pointer at C<$center_x> and C<$center_y> (specified as factor of image
731width/height), generating a new image with width C<$new_width> and height
732C<$new_height>.
733
734#TODO# new width, height, maybe more operators?
735
736Example: rotate the image by 90 degrees
737
738=cut
561 739
562 sub rotate($$$$$$) { 740 sub rotate($$$$$$) {
563 my $img = pop; 741 my $img = pop;
564 $img->rotate ( 742 $img->rotate (
565 $_[0], 743 $_[0],
566 $_[1], 744 $_[1],
567 $_[2] * $img->w * .01, 745 $_[2] * $img->w,
568 $_[3] * $img->h * .01, 746 $_[3] * $img->h,
569 $_[4] * (3.14159265 / 180), 747 $_[4] * (3.14159265 / 180),
570 ) 748 )
571 } 749 }
572 750
573=back 751=back
… …
678} 856}
679 857
680sub on_start { 858sub on_start {
681 my ($self) = @_; 859 my ($self) = @_;
682 860
683 my $expr = $self->x_resource ("background.expr") 861 my $expr = $self->x_resource ("%.expr")
684 or return; 862 or return;
685 863
686 $self->set_expr (parse_expr $expr); 864 $self->set_expr (parse_expr $expr);
687 $self->{border} = $self->x_resource_boolean ("background.border"); 865 $self->{border} = $self->x_resource_boolean ("%.border");
866
867 $MIN_INTERVAL = $self->x_resource ("%.interval");
688 868
689 () 869 ()
690} 870}
691 871

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