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Revision 1.63 by root, Tue Jun 19 18:17:56 2012 UTC vs.
Revision 1.76 by root, Tue Aug 14 23:57:07 2012 UTC

12 12
13 urxvt --background-expr 'background expression' 13 urxvt --background-expr 'background expression'
14 --background-border 14 --background-border
15 --background-interval seconds 15 --background-interval seconds
16 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
17=head1 DESCRIPTION 41=head1 DESCRIPTION
18 42
19This extension manages the terminal background by creating a picture that 43This extension manages the terminal background by creating a picture that
20is behind the text, replacing the normal background colour. 44is behind the text, replacing the normal background colour.
21 45
26to be as simple as possible. 50to be as simple as possible.
27 51
28For 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
29use: 53use:
30 54
31 urxvt --background-expr 'scale load "/path/to/mybg.png"' 55 urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }'
32 56
33Or specified as a X resource: 57Or specified as a X resource:
34 58
35 URxvt.background-expr: scale load "/path/to/mybg.png" 59 URxvt.background-expr: scale keep { load "/path/to/mybg.png" }
36 60
37=head1 THEORY OF OPERATION 61=head1 THEORY OF OPERATION
38 62
39At 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
40expression is evaluated and must yield an image. The image is then 64expression is evaluated and must yield an image. The image is then
53If 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
54window 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
55pixmap 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
56timer elapses), then the expression will be evaluated again. 80timer elapses), then the expression will be evaluated again.
57 81
58For 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"
59image 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
60be 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
61example. That ensures that the picture always fills the terminal, even 85example. That ensures that the picture always fills the terminal, even
62after its size changes. 86after its size changes.
63 87
64=head2 EXPRESSIONS 88=head2 EXPRESSIONS
65 89
66Expressions are normal Perl expressions, in fact, they are Perl blocks - 90Expressions are normal Perl expressions, in fact, they are Perl blocks -
67which means you could use multiple lines and statements: 91which means you could use multiple lines and statements:
68 92
93 scale keep {
69 again 3600; 94 again 3600;
70 if (localtime now)[6]) { 95 if (localtime now)[6]) {
71 return scale load "$HOME/weekday.png"; 96 return load "$HOME/weekday.png";
72 } else { 97 } else {
73 return scale load "$HOME/sunday.png"; 98 return load "$HOME/sunday.png";
99 }
74 } 100 }
75 101
76This expression is 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
77background on Sundays, and F<weekday.png> on all other days. 104Sundays, and F<weekday.png> on all other days.
78 105
79Fortunately, we expect that most expressions will be much simpler, with 106Fortunately, we expect that most expressions will be much simpler, with
80little Perl knowledge needed. 107little Perl knowledge needed.
81 108
82Basically, you always start with a function that "generates" an image 109Basically, you always start with a function that "generates" an image
115horizontal and vertical dimensions. For example, this halves the image 142horizontal and vertical dimensions. For example, this halves the image
116width and doubles the image height: 143width and doubles the image height:
117 144
118 scale 0.5, 2, load "$HOME/mypic.png" 145 scale 0.5, 2, load "$HOME/mypic.png"
119 146
120Other effects than scaling are also readily available, for example, you can 147IF you try out these expressions, you might suffer from some sluggishness,
121tile 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:
122 151
152 scale 0.5, 2, keep { load "$HOME/mypic.png" }
153
154The C<keep> operator executes all the statements inside the braces only
155once, or when it thinks the outcome might change. In other cases it
156returns the last value computed by the brace block.
157
158This means that the C<load> is only executed once, which makes it much
159faster, but also means that more memory is being used, because the loaded
160image must be kept in memory at all times. In this expression, the
161trade-off is likely worth it.
162
163But back to effects: Other effects than scaling are also readily
164available, for example, you can tile the image to fill the whole window,
165instead of resizing it:
166
123 tile load "$HOME/mypic.png" 167 tile keep { load "$HOME/mypic.png" }
124 168
125In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator 169In fact, images returned by C<load> are in C<tile> mode by default, so the
126is kind of superfluous. 170C<tile> operator is kind of superfluous.
127 171
128Another common effect is to mirror the image, so that the same edges touch: 172Another common effect is to mirror the image, so that the same edges
173touch:
129 174
130 mirror load "$HOME/mypic.png" 175 mirror keep { load "$HOME/mypic.png" }
131 176
132This is also a typical background expression: 177Another common background expression is:
133 178
134 rootalign root 179 rootalign root
135 180
136It first takes a snapshot of the screen background image, and then 181This one first takes a snapshot of the screen background image, and then
137moves 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
138pseudo-transparency, as the image seems to be static while the window is 183left corner of the terminal window)- the result is pseudo-transparency:
139moved around. 184the image seems to be static while the window is moved around.
140 185
141=head2 CYCLES AND CACHING 186=head2 COLOUR SPECIFICATIONS
142 187
143=head3 C<load> et al. 188Whenever an operator expects a "colour", then this can be specified in one
189of two ways: Either as string with an X11 colour specification, such as:
144 190
145As has been mentioned before, the expression might be evaluated multiple 191 "red" # named colour
146times. Each time the expression is reevaluated, a new cycle is said to 192 "#f00" # simple rgb
147have begun. Many operators cache their results till the next cycle. 193 "[50]red" # red with 50% alpha
194 "TekHVC:300/50/50" # anything goes
148 195
149For example, the C<load> operator keeps a copy of the image. If it is 196OR as an array reference with one, three or four components:
150asked to load the same image on the next cycle it will not load it again,
151but return the cached copy.
152 197
153This only works for one cycle though, so as long as you load the same 198 [0.5] # 50% gray, 100% alpha
154image every time, it will always be cached, but when you load a different 199 [0.5, 0, 0] # dark red, no green or blur, 100% alpha
155image, it will forget about the first one. 200 [0.5, 0, 0, 0.7] # same with explicit 70% alpha
156 201
157This allows you to either speed things up by keeping multiple images in 202=head2 CACHING AND SENSITIVITY
158memory, or conserve memory by loading images more often.
159 203
160For example, you can keep two images in memory and use a random one like 204Since some operations (such as C<load> and C<blur>) can take a long time,
161this: 205caching results can be very important for a smooth operation. Caching can
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.
162 209
163 my $img1 = load "img1.png"; 210=head3 C<keep { ... }> caching
164 my $img2 = load "img2.png";
165 (0.5 > rand) ? $img1 : $img2
166 211
167Since both images are "loaded" every time the expression is evaluated, 212The most important way to cache expensive operations is to use C<keep {
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
178=head3 C<once { ... }>
179
180Another way to cache expensive operations is to use C<once { ... }>. The
181C<once> operator takes a block of multiple statements enclosed by C<{}> 213... }>. The C<keep> operator takes a block of multiple statements enclosed
182and evaluates it only.. once, returning any images the last statement 214by C<{}> and keeps the return value in memory.
183returned. Further calls simply produce the values from the cache.
184 215
216An expression can be "sensitive" to various external events, such as
217scaling or moving the window, root background changes and timers. Simply
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.
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
185This is most useful for expensive operations, such as C<blur>: 227C<keep> is most useful for expensive operations, such as C<blur>:
186 228
187 rootalign once { blur 20, root } 229 rootalign keep { blur 20, root }
188 230
189This makes a blurred copy of the root background once, and on subsequent 231This makes a blurred copy of the root background once, and on subsequent
190calls, just root-aligns it. Since C<blur> is usually quite slow and 232calls, just root-aligns it. Since C<blur> is usually quite slow and
191C<rootalign> is quite fast, this trades extra memory (For the cached 233C<rootalign> is quite fast, this trades extra memory (for the cached
192blurred pixmap) with speed (blur only needs to be redone when root 234blurred pixmap) with speed (blur only needs to be redone when root
193changes). 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.
194 249
195=head1 REFERENCE 250=head1 REFERENCE
196 251
197=head2 COMMAND LINE SWITCHES 252=head2 COMMAND LINE SWITCHES
198 253
252=item load $path 307=item load $path
253 308
254Loads the image at the given C<$path>. The image is set to plane tiling 309Loads the image at the given C<$path>. The image is set to plane tiling
255mode. 310mode.
256 311
257Loaded images will be cached for one cycle, and shared between temrinals 312If the image is already in memory (e.g. because another terminal instance
258running in the same process (e.g. in C<urxvtd>). 313uses it), then the in-memory copy us returned instead.
259 314
260#=item load_uc $path 315=item load_uc $path
261# 316
262#Load uncached - same as load, but does not cache the image. This function 317Load uncached - same as load, but does not cache the image, which means it
263#is most useufl if you want to optimise a background expression in some 318is I<always> loaded from the filesystem again, even if another copy of it
264#way. 319is in memory at the time.
265 320
266=cut 321=cut
322
323 sub load_uc($) {
324 $self->new_img_from_file ($_[0])
325 }
267 326
268 sub load($) { 327 sub load($) {
269 my ($path) = @_; 328 my ($path) = @_;
270 329
271 $_IMG_CACHE{$path} || do { 330 $_IMG_CACHE{$path} || do {
272 my $img = $self->new_img_from_file ($path); 331 my $img = load_uc $path;
273 Scalar::Util::weaken ($_IMG_CACHE{$path} = $img); 332 Scalar::Util::weaken ($_IMG_CACHE{$path} = $img);
274 $img 333 $img
275 } 334 }
276 } 335 }
277 336
323 382
324=item merge $img ... 383=item merge $img ...
325 384
326Takes any number of images and merges them together, creating a single 385Takes any number of images and merges them together, creating a single
327image containing them all. The tiling mode of the first image is used as 386image containing them all. The tiling mode of the first image is used as
328the tiling mdoe of the resulting image. 387the tiling mode of the resulting image.
329 388
330This function is called automatically when an expression returns multiple 389This function is called automatically when an expression returns multiple
331images. 390images.
332 391
333=cut 392=cut
362 $base->draw ($_) 421 $base->draw ($_)
363 for @_; 422 for @_;
364 423
365 $base 424 $base
366 } 425 }
426
427=back
367 428
368=head2 TILING MODES 429=head2 TILING MODES
369 430
370The following operators modify the tiling mode of an image, that is, the 431The following operators modify the tiling mode of an image, that is, the
371way that pixels outside the image area are painted when the image is used. 432way that pixels outside the image area are painted when the image is used.
468Using these functions make your expression sensitive to window moves. 529Using these functions make your expression sensitive to window moves.
469 530
470These functions are mainly useful to align images to the root window. 531These functions are mainly useful to align images to the root window.
471 532
472Example: load an image and align it so it looks as if anchored to the 533Example: load an image and align it so it looks as if anchored to the
473background. 534background (that's exactly what C<rootalign> does btw.):
474 535
475 move -TX, -TY, load "mybg.png" 536 move -TX, -TY, keep { load "mybg.png" }
476 537
477=item TW 538=item TW
478 539
479Return the width (C<TW>) and height (C<TH>) of the terminal window (the 540Return the width (C<TW>) and height (C<TH>) of the terminal window (the
480terminal window is the full window by default, and the character area only 541terminal window is the full window by default, and the character area only
486the window size to conserve memory. 547the window size to conserve memory.
487 548
488Example: take the screen background, clip it to the window size, blur it a 549Example: take the screen background, clip it to the window size, blur it a
489bit, align it to the window position and use it as background. 550bit, align it to the window position and use it as background.
490 551
491 clip move -TX, -TY, once { blur 5, root } 552 clip move -TX, -TY, keep { blur 5, root }
492 553
493=cut 554=cut
494 555
495 sub TX() { $frame->[FR_AGAIN]{position} = 1; $x } 556 sub TX() { $frame->[FR_AGAIN]{position} = 1; $x }
496 sub TY() { $frame->[FR_AGAIN]{position} = 1; $y } 557 sub TY() { $frame->[FR_AGAIN]{position} = 1; $y }
510C<$seconds> seconds. 571C<$seconds> seconds.
511 572
512Example: load some image and rotate it according to the time of day (as if it were 573Example: load some image and rotate it according to the time of day (as if it were
513the hour pointer of a clock). Update this image every minute. 574the hour pointer of a clock). Update this image every minute.
514 575
576 again 60;
515 again 60; rotate 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png" 577 rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" }
516 578
517=item counter $seconds 579=item counter $seconds
518 580
519Like C<again>, but also returns an increasing counter value, starting at 581Like C<again>, but also returns an increasing counter value, starting at
5200, which might be useful for some simple animation effects. 5820, which might be useful for some simple animation effects.
557assumed. 619assumed.
558 620
559Example: load an image, blur it, and clip it to the window size to save 621Example: load an image, blur it, and clip it to the window size to save
560memory. 622memory.
561 623
562 clip blur 10, load "mybg.png" 624 clip keep { blur 10, load "mybg.png" }
563 625
564=cut 626=cut
565 627
566 sub clip($;$$;$$) { 628 sub clip($;$$;$$) {
567 my $img = pop; 629 my $img = pop;
661the terminal window (or the box specified by C<$width> and C<$height> if 723the terminal window (or the box specified by C<$width> and C<$height> if
662given). 724given).
663 725
664Example: load an image and center it. 726Example: load an image and center it.
665 727
666 center pad load "mybg.png" 728 center keep { pad load "mybg.png" }
667 729
668=item rootalign $img 730=item rootalign $img
669 731
670Moves the image so that it appears glued to the screen as opposed to the 732Moves the image so that it appears glued to the screen as opposed to the
671window. This gives the illusion of a larger area behind the window. It is 733window. This gives the illusion of a larger area behind the window. It is
672exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the 734exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the
673top left of the screen. 735top left of the screen.
674 736
675Example: load a background image, put it in mirror mode and root align it. 737Example: load a background image, put it in mirror mode and root align it.
676 738
677 rootalign mirror load "mybg.png" 739 rootalign keep { mirror load "mybg.png" }
678 740
679Example: take the screen background and align it, giving the illusion of 741Example: take the screen background and align it, giving the illusion of
680transparency as long as the window isn't in front of other windows. 742transparency as long as the window isn't in front of other windows.
681 743
682 rootalign root 744 rootalign root
707 769
708 sub rootalign($) { 770 sub rootalign($) {
709 move -TX, -TY, $_[0] 771 move -TX, -TY, $_[0]
710 } 772 }
711 773
712=item rotate $center_x, $center_y, $degrees 774=item rotate $center_x, $center_y, $degrees, $img
713 775
714Rotates the image by C<$degrees> degrees, counter-clockwise, around the 776Rotates the image clockwise by C<$degrees> degrees, around the point at
715pointer at C<$center_x> and C<$center_y> (specified as factor of image 777C<$center_x> and C<$center_y> (specified as factor of image width/height).
716width/height).
717 778
718#TODO# new width, height, maybe more operators?
719
720Example: rotate the image by 90 degrees 779Example: rotate the image by 90 degrees around it's center.
780
781 rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" }
721 782
722=cut 783=cut
723 784
724 sub rotate($$$$) { 785 sub rotate($$$$) {
725 my $img = pop; 786 my $img = pop;
736 797
737The following operators change the pixels of the image. 798The following operators change the pixels of the image.
738 799
739=over 4 800=over 4
740 801
802=item tint $color, $img
803
804Tints the image in the given colour.
805
806Example: tint the image red.
807
808 tint "red", load "rgb.png"
809
810Example: the same, but specify the colour by component.
811
812 tint [1, 0, 0], load "rgb.png"
813
814=cut
815
816 sub tint($$) {
817 $_[1]->tint ($_[0])
818 }
819
741=item contrast $factor, $img 820=item contrast $factor, $img
742 821
743=item contrast $r, $g, $b, $img 822=item contrast $r, $g, $b, $img
744 823
745=item contrast $r, $g, $b, $a, $img 824=item contrast $r, $g, $b, $a, $img
774latter in a white picture. 853latter in a white picture.
775 854
776Due to idiosyncrasies in the underlying XRender extension, biases less 855Due to idiosyncrasies in the underlying XRender extension, biases less
777than zero can be I<very> slow. 856than zero can be I<very> slow.
778 857
858You can also try the experimental(!) C<muladd> operator.
859
779=cut 860=cut
780 861
781 sub contrast($$;$$;$) { 862 sub contrast($$;$$;$) {
782 my $img = pop; 863 my $img = pop;
783 my ($r, $g, $b, $a) = @_; 864 my ($r, $g, $b, $a) = @_;
798 $a = 1 if @_ < 4; 879 $a = 1 if @_ < 4;
799 880
800 $img = $img->clone; 881 $img = $img->clone;
801 $img->brightness ($r, $g, $b, $a); 882 $img->brightness ($r, $g, $b, $a);
802 $img 883 $img
884 }
885
886=item muladd $mul, $add, $img # EXPERIMENTAL
887
888First multipliesthe pixels by C<$mul>, then adds C<$add>. This cna be used
889to implement brightness and contrast at the same time, with a wider value
890range than contrast and brightness operators.
891
892Due to numerous bugs in XRender implementations, it can also introduce a
893number of visual artifacts.
894
895Example: increase contrast by a factor of C<$c> without changing image
896brightness too much.
897
898 muladd $c, (1 - $c) * 0.5, $img
899
900=cut
901
902 sub muladd($$$) {
903 $_[2]->muladd ($_[0], $_[1])
803 } 904 }
804 905
805=item blur $radius, $img 906=item blur $radius, $img
806 907
807=item blur $radius_horz, $radius_vert, $img 908=item blur $radius_horz, $radius_vert, $img
828Anything that didn't fit any of the other categories, even after applying 929Anything that didn't fit any of the other categories, even after applying
829force and closing our eyes. 930force and closing our eyes.
830 931
831=over 4 932=over 4
832 933
833=item once { ... } 934=item keep { ... }
834 935
835This function takes a code block as argument, that is, one or more 936This operator takes a code block as argument, that is, one or more
836statements enclosed by braces. 937statements enclosed by braces.
837 938
838The trick is that this code block is only evaluated once - future calls 939The trick is that this code block is only evaluated when the outcome
839will simply return the original image (yes, it should only be used with 940changes - on other calls the C<keep> simply returns the image it computed
840images). 941previously (yes, it should only be used with images). Or in other words,
942C<keep> I<caches> the result of the code block so it doesn't need to be
943computed again.
841 944
842This can be extremely useful to avoid redoing the same slow operations 945This can be extremely useful to avoid redoing slow operations - for
843again and again- for example, if your background expression takes the root 946example, if your background expression takes the root background, blurs it
844background, blurs it and then root-aligns it it would have to blur the 947and then root-aligns it it would have to blur the root background on every
845root background on every window move or resize. 948window move or resize.
949
950Another example is C<load>, which can be quite slow.
846 951
847In fact, urxvt itself encloses the whole expression in some kind of 952In fact, urxvt itself encloses the whole expression in some kind of
848C<once> block so it only is reevaluated as required. 953C<keep> block so it only is reevaluated as required.
849 954
850Putting the blur into a C<once> block will make sure the blur is only done 955Putting the blur into a C<keep> block will make sure the blur is only done
851once: 956once, while the C<rootalign> is still done each time the window moves.
852 957
853 rootlign once { blur 10, root } 958 rootalign keep { blur 10, root }
854 959
855This leaves the question of how to force reevaluation of the block, 960This leaves the question of how to force reevaluation of the block,
856in case the root background changes: If expression inside the block 961in case the root background changes: If expression inside the block
857is sensitive to some event (root background changes, window geometry 962is sensitive to some event (root background changes, window geometry
858changes), then it will be reevaluated automatically as needed. 963changes), then it will be reevaluated automatically as needed.
859 964
860=item once_again
861
862Resets all C<once> block as if they had never been called, i.e. on the
863next call they will be reevaluated again.
864
865=cut 965=cut
866 966
867 sub once(&) { 967 sub keep(&) {
868 my $id = $_[0]+0; 968 my $id = $_[0]+0;
869 969
870 local $frame = $self->{frame_cache}{$id} ||= [$frame]; 970 local $frame = $self->{frame_cache}{$id} ||= [$frame];
871 971
872 unless ($frame->[FR_CACHE]) { 972 unless ($frame->[FR_CACHE]) {
879 # clear this frame cache, also for all parents 979 # clear this frame cache, also for all parents
880 for (my $frame = $frame; $frame; $frame = $frame->[0]) { 980 for (my $frame = $frame; $frame; $frame = $frame->[0]) {
881 undef $frame->[FR_CACHE]; 981 undef $frame->[FR_CACHE];
882 } 982 }
883 983
884 unless ($self->{term}) {
885 use Data::Dump;
886 ddx $frame;
887 exit;
888 }
889
890 $self->recalculate; 984 $self->recalculate;
891 }); 985 });
892 }; 986 };
893 987
894 # in scalar context we always return the first original result, which 988 # in scalar context we always return the first original result, which
896 wantarray 990 wantarray
897 ? @{ $frame->[FR_CACHE] } 991 ? @{ $frame->[FR_CACHE] }
898 : $frame->[FR_CACHE][0] 992 : $frame->[FR_CACHE][0]
899 } 993 }
900 994
901 sub once_again() { 995# sub keep_clear() {
902 delete $self->{frame_cache}; 996# delete $self->{frame_cache};
903 } 997# }
904 998
905=back 999=back
906 1000
907=cut 1001=cut
908 1002
921 1015
922# compiles a parsed expression 1016# compiles a parsed expression
923sub set_expr { 1017sub set_expr {
924 my ($self, $expr) = @_; 1018 my ($self, $expr) = @_;
925 1019
926 $self->{root} = []; 1020 $self->{root} = []; # the outermost frame
927 $self->{expr} = $expr; 1021 $self->{expr} = $expr;
928 $self->recalculate; 1022 $self->recalculate;
929} 1023}
930 1024
931# takes a hash of sensitivity indicators and installs watchers 1025# takes a hash of sensitivity indicators and installs watchers
993 1087
994 # set environment to evaluate user expression 1088 # set environment to evaluate user expression
995 1089
996 local $self = $arg_self; 1090 local $self = $arg_self;
997 local $HOME = $ENV{HOME}; 1091 local $HOME = $ENV{HOME};
998 local $frame = []; 1092 local $frame = $self->{root};
999 1093
1000 ($x, $y, $w, $h) = $self->background_geometry ($self->{border}); 1094 ($x, $y, $w, $h) = $self->background_geometry ($self->{border});
1001 1095
1002 # evaluate user expression 1096 # evaluate user expression
1003 1097

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