… | |
… | |
26 | to be as simple as possible. |
26 | to be as simple as possible. |
27 | |
27 | |
28 | For example, to load an image and scale it to the window size, you would |
28 | For example, to load an image and scale it to the window size, you would |
29 | use: |
29 | use: |
30 | |
30 | |
31 | urxvt --background-expr 'scale load "/path/to/mybg.png"' |
31 | urxvt --background-expr 'scale keep { load "/path/to/mybg.png" }' |
32 | |
32 | |
33 | Or specified as a X resource: |
33 | Or specified as a X resource: |
34 | |
34 | |
35 | URxvt.background-expr: scale load "/path/to/mybg.png" |
35 | URxvt.background-expr: scale keep { load "/path/to/mybg.png" } |
36 | |
36 | |
37 | =head1 THEORY OF OPERATION |
37 | =head1 THEORY OF OPERATION |
38 | |
38 | |
39 | At startup, just before the window is mapped for the first time, the |
39 | At startup, just before the window is mapped for the first time, the |
40 | expression is evaluated and must yield an image. The image is then |
40 | expression is evaluated and must yield an image. The image is then |
… | |
… | |
53 | If any of the parameters that the expression relies on changes (when the |
53 | If any of the parameters that the expression relies on changes (when the |
54 | window is moved or resized, its position or size changes; when the root |
54 | window is moved or resized, its position or size changes; when the root |
55 | pixmap is replaced by another one the root background changes; or when the |
55 | pixmap is replaced by another one the root background changes; or when the |
56 | timer elapses), then the expression will be evaluated again. |
56 | timer elapses), then the expression will be evaluated again. |
57 | |
57 | |
58 | For example, an expression such as C<scale load "$HOME/mybg.png"> scales the |
58 | For example, an expression such as C<scale keep { load "$HOME/mybg.png" |
59 | image to the window size, so it relies on the window size and will |
59 | }> scales the image to the window size, so it relies on the window size |
60 | be reevaluated each time it is changed, but not when it moves for |
60 | and will be reevaluated each time it is changed, but not when it moves for |
61 | example. That ensures that the picture always fills the terminal, even |
61 | example. That ensures that the picture always fills the terminal, even |
62 | after its size changes. |
62 | after its size changes. |
63 | |
63 | |
64 | =head2 EXPRESSIONS |
64 | =head2 EXPRESSIONS |
65 | |
65 | |
66 | Expressions are normal Perl expressions, in fact, they are Perl blocks - |
66 | Expressions are normal Perl expressions, in fact, they are Perl blocks - |
67 | which means you could use multiple lines and statements: |
67 | which means you could use multiple lines and statements: |
68 | |
68 | |
|
|
69 | scale keep { |
69 | again 3600; |
70 | again 3600; |
70 | if (localtime now)[6]) { |
71 | if (localtime now)[6]) { |
71 | return scale load "$HOME/weekday.png"; |
72 | return load "$HOME/weekday.png"; |
72 | } else { |
73 | } else { |
73 | return scale load "$HOME/sunday.png"; |
74 | return load "$HOME/sunday.png"; |
|
|
75 | } |
74 | } |
76 | } |
75 | |
77 | |
76 | This expression is evaluated once per hour. It will set F<sunday.png> as |
78 | This inner expression is evaluated once per hour (and whenever the |
|
|
79 | terminal window is resized). It sets F<sunday.png> as background on |
77 | background on Sundays, and F<weekday.png> on all other days. |
80 | Sundays, and F<weekday.png> on all other days. |
78 | |
81 | |
79 | Fortunately, we expect that most expressions will be much simpler, with |
82 | Fortunately, we expect that most expressions will be much simpler, with |
80 | little Perl knowledge needed. |
83 | little Perl knowledge needed. |
81 | |
84 | |
82 | Basically, you always start with a function that "generates" an image |
85 | Basically, you always start with a function that "generates" an image |
… | |
… | |
115 | horizontal and vertical dimensions. For example, this halves the image |
118 | horizontal and vertical dimensions. For example, this halves the image |
116 | width and doubles the image height: |
119 | width and doubles the image height: |
117 | |
120 | |
118 | scale 0.5, 2, load "$HOME/mypic.png" |
121 | scale 0.5, 2, load "$HOME/mypic.png" |
119 | |
122 | |
120 | Other effects than scaling are also readily available, for example, you can |
123 | IF you try out these expressions, you might suffer from some sluggishness, |
121 | tile the image to fill the whole window, instead of resizing it: |
124 | because each time the terminal is resized, it loads the PNG image again |
|
|
125 | and scales it. Scaling is usually fast (and unavoidable), but loading the |
|
|
126 | image can be quite time consuming. This is where C<keep> comes in handy: |
122 | |
127 | |
|
|
128 | scale 0.5, 2, keep { load "$HOME/mypic.png" } |
|
|
129 | |
|
|
130 | The C<keep> operator executes all the statements inside the braces only |
|
|
131 | once, or when it thinks the outcome might change. In other cases it |
|
|
132 | returns the last value computed by the brace block. |
|
|
133 | |
|
|
134 | This means that the C<load> is only executed once, which makes it much |
|
|
135 | faster, but also means that more memory is being used, because the loaded |
|
|
136 | image must be kept in memory at all times. In this expression, the |
|
|
137 | trade-off is likely worth it. |
|
|
138 | |
|
|
139 | But back to effects: Other effects than scaling are also readily |
|
|
140 | available, for example, you can tile the image to fill the whole window, |
|
|
141 | instead of resizing it: |
|
|
142 | |
123 | tile load "$HOME/mypic.png" |
143 | tile keep { load "$HOME/mypic.png" } |
124 | |
144 | |
125 | In fact, images returned by C<load> are in C<tile> mode by default, so the C<tile> operator |
145 | In fact, images returned by C<load> are in C<tile> mode by default, so the |
126 | is kind of superfluous. |
146 | C<tile> operator is kind of superfluous. |
127 | |
147 | |
128 | Another common effect is to mirror the image, so that the same edges touch: |
148 | Another common effect is to mirror the image, so that the same edges |
|
|
149 | touch: |
129 | |
150 | |
130 | mirror load "$HOME/mypic.png" |
151 | mirror keep { load "$HOME/mypic.png" } |
131 | |
152 | |
132 | This is also a typical background expression: |
153 | Another common background expression is: |
133 | |
154 | |
134 | rootalign root |
155 | rootalign root |
135 | |
156 | |
136 | It first takes a snapshot of the screen background image, and then |
157 | This one first takes a snapshot of the screen background image, and then |
137 | moves it to the upper left corner of the screen - the result is |
158 | moves it to the upper left corner of the screen (as opposed to the upper |
138 | pseudo-transparency, as the image seems to be static while the window is |
159 | left corner of the terminal window)- the result is pseudo-transparency: |
139 | moved around. |
160 | the image seems to be static while the window is moved around. |
140 | |
161 | |
141 | =head2 CYCLES AND CACHING |
162 | =head2 COLOUR SPECIFICATIONS |
142 | |
163 | |
143 | =head3 C<load> et al. |
164 | Whenever an operator expects a "colour", then this can be specified in one |
|
|
165 | of two ways: Either as string with an X11 colour specification, such as: |
144 | |
166 | |
145 | As has been mentioned before, the expression might be evaluated multiple |
167 | "red" # named colour |
146 | times. Each time the expression is reevaluated, a new cycle is said to |
168 | "#f00" # simple rgb |
147 | have begun. Many operators cache their results till the next cycle. |
169 | "[50]red" # red with 50% alpha |
|
|
170 | "TekHVC:300/50/50" # anything goes |
148 | |
171 | |
149 | For example, the C<load> operator keeps a copy of the image. If it is |
172 | OR as an array reference with one, three or four components: |
150 | asked to load the same image on the next cycle it will not load it again, |
|
|
151 | but return the cached copy. |
|
|
152 | |
173 | |
153 | This only works for one cycle though, so as long as you load the same |
174 | [0.5] # 50% gray, 100% alpha |
154 | image every time, it will always be cached, but when you load a different |
175 | [0.5, 0, 0] # dark red, no green or blur, 100% alpha |
155 | image, it will forget about the first one. |
176 | [0.5, 0, 0, 0.7] # same with explicit 70% alpha |
156 | |
177 | |
157 | This allows you to either speed things up by keeping multiple images in |
178 | =head2 CACHING AND SENSITIVITY |
158 | memory, or conserve memory by loading images more often. |
|
|
159 | |
179 | |
160 | For example, you can keep two images in memory and use a random one like |
180 | Since some operations (such as C<load> and C<blur>) can take a long time, |
161 | this: |
181 | caching results can be very important for a smooth operation. Caching can |
|
|
182 | also be useful to reduce memory usage, though, for example, when an image |
|
|
183 | is cached by C<load>, it could be shared by multiple terminal windows |
|
|
184 | running inside urxvtd. |
162 | |
185 | |
163 | my $img1 = load "img1.png"; |
186 | =head3 C<keep { ... }> caching |
164 | my $img2 = load "img2.png"; |
|
|
165 | (0.5 > rand) ? $img1 : $img2 |
|
|
166 | |
187 | |
167 | Since both images are "loaded" every time the expression is evaluated, |
188 | The most important way to cache expensive operations is to use C<keep { |
168 | they 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 | |
|
|
174 | Here, a path is selected randomly, and load is only called for one image, |
|
|
175 | so keeps only one image in memory. If, on the next evaluation, luck |
|
|
176 | decides to use the other path, then it will have to load that image again. |
|
|
177 | |
|
|
178 | =head3 C<once { ... }> |
|
|
179 | |
|
|
180 | Another way to cache expensive operations is to use C<once { ... }>. The |
|
|
181 | C<once> operator takes a block of multiple statements enclosed by C<{}> |
189 | ... }>. The C<keep> operator takes a block of multiple statements enclosed |
182 | and evaluates it only.. once, returning any images the last statement |
190 | by C<{}> and keeps the return value in memory. |
183 | returned. Further calls simply produce the values from the cache. |
|
|
184 | |
191 | |
|
|
192 | An expression can be "sensitive" to various external events, such as |
|
|
193 | scaling or moving the window, root background changes and timers. Simply |
|
|
194 | using an expression (such as C<scale> without parameters) that depends on |
|
|
195 | certain changing values (called "variables"), or using those variables |
|
|
196 | directly, will make an expression sensitive to these events - for example, |
|
|
197 | using C<scale> or C<TW> will make the expression sensitive to the terminal |
|
|
198 | size, and thus to resizing events. |
|
|
199 | |
|
|
200 | When such an event happens, C<keep> will automatically trigger a |
|
|
201 | reevaluation of the whole expression with the new value of the expression. |
|
|
202 | |
185 | This is most useful for expensive operations, such as C<blur>: |
203 | C<keep> is most useful for expensive operations, such as C<blur>: |
186 | |
204 | |
187 | rootalign once { blur 20, root } |
205 | rootalign keep { blur 20, root } |
188 | |
206 | |
189 | This makes a blurred copy of the root background once, and on subsequent |
207 | This makes a blurred copy of the root background once, and on subsequent |
190 | calls, just root-aligns it. Since C<blur> is usually quite slow and |
208 | calls, just root-aligns it. Since C<blur> is usually quite slow and |
191 | C<rootalign> is quite fast, this trades extra memory (For the cached |
209 | C<rootalign> is quite fast, this trades extra memory (for the cached |
192 | blurred pixmap) with speed (blur only needs to be redone when root |
210 | blurred pixmap) with speed (blur only needs to be redone when root |
193 | changes). |
211 | changes). |
|
|
212 | |
|
|
213 | =head3 C<load> caching |
|
|
214 | |
|
|
215 | The C<load> operator itself does not keep images in memory, but as long as |
|
|
216 | the image is still in memory, C<load> will use the in-memory image instead |
|
|
217 | of loading it freshly from disk. |
|
|
218 | |
|
|
219 | That means that this expression: |
|
|
220 | |
|
|
221 | keep { load "$HOME/path..." } |
|
|
222 | |
|
|
223 | Not only caches the image in memory, other terminal instances that try to |
|
|
224 | C<load> it can reuse that in-memory copy. |
194 | |
225 | |
195 | =head1 REFERENCE |
226 | =head1 REFERENCE |
196 | |
227 | |
197 | =head2 COMMAND LINE SWITCHES |
228 | =head2 COMMAND LINE SWITCHES |
198 | |
229 | |
… | |
… | |
252 | =item load $path |
283 | =item load $path |
253 | |
284 | |
254 | Loads the image at the given C<$path>. The image is set to plane tiling |
285 | Loads the image at the given C<$path>. The image is set to plane tiling |
255 | mode. |
286 | mode. |
256 | |
287 | |
257 | Loaded images will be cached for one cycle, and shared between temrinals |
288 | If the image is already in memory (e.g. because another terminal instance |
258 | running in the same process (e.g. in C<urxvtd>). |
289 | uses it), then the in-memory copy us returned instead. |
259 | |
290 | |
260 | #=item load_uc $path |
291 | =item load_uc $path |
261 | # |
292 | |
262 | #Load uncached - same as load, but does not cache the image. This function |
293 | Load uncached - same as load, but does not cache the image, which means it |
263 | #is most useufl if you want to optimise a background expression in some |
294 | is I<always> loaded from the filesystem again, even if another copy of it |
264 | #way. |
295 | is in memory at the time. |
265 | |
296 | |
266 | =cut |
297 | =cut |
|
|
298 | |
|
|
299 | sub load_uc($) { |
|
|
300 | $self->new_img_from_file ($_[0]) |
|
|
301 | } |
267 | |
302 | |
268 | sub load($) { |
303 | sub load($) { |
269 | my ($path) = @_; |
304 | my ($path) = @_; |
270 | |
305 | |
271 | $_IMG_CACHE{$path} || do { |
306 | $_IMG_CACHE{$path} || do { |
272 | my $img = $self->new_img_from_file ($path); |
307 | my $img = load_uc $path; |
273 | Scalar::Util::weaken ($_IMG_CACHE{$path} = $img); |
308 | Scalar::Util::weaken ($_IMG_CACHE{$path} = $img); |
274 | $img |
309 | $img |
275 | } |
310 | } |
276 | } |
311 | } |
277 | |
312 | |
… | |
… | |
323 | |
358 | |
324 | =item merge $img ... |
359 | =item merge $img ... |
325 | |
360 | |
326 | Takes any number of images and merges them together, creating a single |
361 | Takes any number of images and merges them together, creating a single |
327 | image containing them all. The tiling mode of the first image is used as |
362 | image containing them all. The tiling mode of the first image is used as |
328 | the tiling mdoe of the resulting image. |
363 | the tiling mode of the resulting image. |
329 | |
364 | |
330 | This function is called automatically when an expression returns multiple |
365 | This function is called automatically when an expression returns multiple |
331 | images. |
366 | images. |
332 | |
367 | |
333 | =cut |
368 | =cut |
… | |
… | |
468 | Using these functions make your expression sensitive to window moves. |
503 | Using these functions make your expression sensitive to window moves. |
469 | |
504 | |
470 | These functions are mainly useful to align images to the root window. |
505 | These functions are mainly useful to align images to the root window. |
471 | |
506 | |
472 | Example: load an image and align it so it looks as if anchored to the |
507 | Example: load an image and align it so it looks as if anchored to the |
473 | background. |
508 | background (that's exactly what C<rootalign> does btw.): |
474 | |
509 | |
475 | move -TX, -TY, load "mybg.png" |
510 | move -TX, -TY, keep { load "mybg.png" } |
476 | |
511 | |
477 | =item TW |
512 | =item TW |
478 | |
513 | |
479 | Return the width (C<TW>) and height (C<TH>) of the terminal window (the |
514 | Return the width (C<TW>) and height (C<TH>) of the terminal window (the |
480 | terminal window is the full window by default, and the character area only |
515 | terminal window is the full window by default, and the character area only |
… | |
… | |
486 | the window size to conserve memory. |
521 | the window size to conserve memory. |
487 | |
522 | |
488 | Example: take the screen background, clip it to the window size, blur it a |
523 | Example: take the screen background, clip it to the window size, blur it a |
489 | bit, align it to the window position and use it as background. |
524 | bit, align it to the window position and use it as background. |
490 | |
525 | |
491 | clip move -TX, -TY, once { blur 5, root } |
526 | clip move -TX, -TY, keep { blur 5, root } |
492 | |
527 | |
493 | =cut |
528 | =cut |
494 | |
529 | |
495 | sub TX() { $frame->[FR_AGAIN]{position} = 1; $x } |
530 | sub TX() { $frame->[FR_AGAIN]{position} = 1; $x } |
496 | sub TY() { $frame->[FR_AGAIN]{position} = 1; $y } |
531 | sub TY() { $frame->[FR_AGAIN]{position} = 1; $y } |
… | |
… | |
510 | C<$seconds> seconds. |
545 | C<$seconds> seconds. |
511 | |
546 | |
512 | Example: load some image and rotate it according to the time of day (as if it were |
547 | Example: load some image and rotate it according to the time of day (as if it were |
513 | the hour pointer of a clock). Update this image every minute. |
548 | the hour pointer of a clock). Update this image every minute. |
514 | |
549 | |
|
|
550 | again 60; |
515 | again 60; rotate 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png" |
551 | rotate 50, 50, (now % 86400) * -72 / 8640, scale keep { load "myclock.png" } |
516 | |
552 | |
517 | =item counter $seconds |
553 | =item counter $seconds |
518 | |
554 | |
519 | Like C<again>, but also returns an increasing counter value, starting at |
555 | Like C<again>, but also returns an increasing counter value, starting at |
520 | 0, which might be useful for some simple animation effects. |
556 | 0, which might be useful for some simple animation effects. |
… | |
… | |
557 | assumed. |
593 | assumed. |
558 | |
594 | |
559 | Example: load an image, blur it, and clip it to the window size to save |
595 | Example: load an image, blur it, and clip it to the window size to save |
560 | memory. |
596 | memory. |
561 | |
597 | |
562 | clip blur 10, load "mybg.png" |
598 | clip keep { blur 10, load "mybg.png" } |
563 | |
599 | |
564 | =cut |
600 | =cut |
565 | |
601 | |
566 | sub clip($;$$;$$) { |
602 | sub clip($;$$;$$) { |
567 | my $img = pop; |
603 | my $img = pop; |
… | |
… | |
661 | the terminal window (or the box specified by C<$width> and C<$height> if |
697 | the terminal window (or the box specified by C<$width> and C<$height> if |
662 | given). |
698 | given). |
663 | |
699 | |
664 | Example: load an image and center it. |
700 | Example: load an image and center it. |
665 | |
701 | |
666 | center pad load "mybg.png" |
702 | center keep { pad load "mybg.png" } |
667 | |
703 | |
668 | =item rootalign $img |
704 | =item rootalign $img |
669 | |
705 | |
670 | Moves the image so that it appears glued to the screen as opposed to the |
706 | Moves the image so that it appears glued to the screen as opposed to the |
671 | window. This gives the illusion of a larger area behind the window. It is |
707 | window. This gives the illusion of a larger area behind the window. It is |
672 | exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the |
708 | exactly equivalent to C<move -TX, -TY>, that is, it moves the image to the |
673 | top left of the screen. |
709 | top left of the screen. |
674 | |
710 | |
675 | Example: load a background image, put it in mirror mode and root align it. |
711 | Example: load a background image, put it in mirror mode and root align it. |
676 | |
712 | |
677 | rootalign mirror load "mybg.png" |
713 | rootalign keep { mirror load "mybg.png" } |
678 | |
714 | |
679 | Example: take the screen background and align it, giving the illusion of |
715 | Example: take the screen background and align it, giving the illusion of |
680 | transparency as long as the window isn't in front of other windows. |
716 | transparency as long as the window isn't in front of other windows. |
681 | |
717 | |
682 | rootalign root |
718 | rootalign root |
… | |
… | |
707 | |
743 | |
708 | sub rootalign($) { |
744 | sub rootalign($) { |
709 | move -TX, -TY, $_[0] |
745 | move -TX, -TY, $_[0] |
710 | } |
746 | } |
711 | |
747 | |
712 | =item rotate $center_x, $center_y, $degrees |
748 | =item rotate $center_x, $center_y, $degrees, $img |
713 | |
749 | |
714 | Rotates the image by C<$degrees> degrees, counter-clockwise, around the |
750 | Rotates the image clockwise by C<$degrees> degrees, around the point at |
715 | pointer at C<$center_x> and C<$center_y> (specified as factor of image |
751 | C<$center_x> and C<$center_y> (specified as factor of image width/height). |
716 | width/height). |
|
|
717 | |
752 | |
718 | #TODO# new width, height, maybe more operators? |
|
|
719 | |
|
|
720 | Example: rotate the image by 90 degrees |
753 | Example: rotate the image by 90 degrees around it's center. |
|
|
754 | |
|
|
755 | rotate 0.5, 0.5, 90, keep { load "$HOME/mybg.png" } |
721 | |
756 | |
722 | =cut |
757 | =cut |
723 | |
758 | |
724 | sub rotate($$$$) { |
759 | sub rotate($$$$) { |
725 | my $img = pop; |
760 | my $img = pop; |
… | |
… | |
736 | |
771 | |
737 | The following operators change the pixels of the image. |
772 | The following operators change the pixels of the image. |
738 | |
773 | |
739 | =over 4 |
774 | =over 4 |
740 | |
775 | |
|
|
776 | =item tint $color, $img |
|
|
777 | |
|
|
778 | Tints the image in the given colour. |
|
|
779 | |
|
|
780 | Example: tint the image red. |
|
|
781 | |
|
|
782 | tint "red", load "rgb.png" |
|
|
783 | |
|
|
784 | Example: the same, but specify the colour by component. |
|
|
785 | |
|
|
786 | tint [1, 0, 0], load "rgb.png" |
|
|
787 | |
|
|
788 | =cut |
|
|
789 | |
|
|
790 | sub tint($$) { |
|
|
791 | $_[1]->tint ($_[0]) |
|
|
792 | } |
|
|
793 | |
741 | =item contrast $factor, $img |
794 | =item contrast $factor, $img |
742 | |
795 | |
743 | =item contrast $r, $g, $b, $img |
796 | =item contrast $r, $g, $b, $img |
744 | |
797 | |
745 | =item contrast $r, $g, $b, $a, $img |
798 | =item contrast $r, $g, $b, $a, $img |
… | |
… | |
828 | Anything that didn't fit any of the other categories, even after applying |
881 | Anything that didn't fit any of the other categories, even after applying |
829 | force and closing our eyes. |
882 | force and closing our eyes. |
830 | |
883 | |
831 | =over 4 |
884 | =over 4 |
832 | |
885 | |
833 | =item once { ... } |
886 | =item keep { ... } |
834 | |
887 | |
835 | This function takes a code block as argument, that is, one or more |
888 | This operator takes a code block as argument, that is, one or more |
836 | statements enclosed by braces. |
889 | statements enclosed by braces. |
837 | |
890 | |
838 | The trick is that this code block is only evaluated once - future calls |
891 | The trick is that this code block is only evaluated when the outcome |
839 | will simply return the original image (yes, it should only be used with |
892 | changes - on other calls the C<keep> simply returns the image it computed |
840 | images). |
893 | previously (yes, it should only be used with images). Or in other words, |
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|
894 | C<keep> I<caches> the result of the code block so it doesn't need to be |
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|
895 | computed again. |
841 | |
896 | |
842 | This can be extremely useful to avoid redoing the same slow operations |
897 | This can be extremely useful to avoid redoing slow operations - for |
843 | again and again- for example, if your background expression takes the root |
898 | example, if your background expression takes the root background, blurs it |
844 | background, blurs it and then root-aligns it it would have to blur the |
899 | and then root-aligns it it would have to blur the root background on every |
845 | root background on every window move or resize. |
900 | window move or resize. |
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|
901 | |
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|
902 | Another example is C<load>, which can be quite slow. |
846 | |
903 | |
847 | In fact, urxvt itself encloses the whole expression in some kind of |
904 | In fact, urxvt itself encloses the whole expression in some kind of |
848 | C<once> block so it only is reevaluated as required. |
905 | C<keep> block so it only is reevaluated as required. |
849 | |
906 | |
850 | Putting the blur into a C<once> block will make sure the blur is only done |
907 | Putting the blur into a C<keep> block will make sure the blur is only done |
851 | once: |
908 | once, while the C<rootalign> is still done each time the window moves. |
852 | |
909 | |
853 | rootlign once { blur 10, root } |
910 | rootalign keep { blur 10, root } |
854 | |
911 | |
855 | This leaves the question of how to force reevaluation of the block, |
912 | This leaves the question of how to force reevaluation of the block, |
856 | in case the root background changes: If expression inside the block |
913 | in case the root background changes: If expression inside the block |
857 | is sensitive to some event (root background changes, window geometry |
914 | is sensitive to some event (root background changes, window geometry |
858 | changes), then it will be reevaluated automatically as needed. |
915 | changes), then it will be reevaluated automatically as needed. |
859 | |
916 | |
860 | =item once_again |
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|
861 | |
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|
862 | Resets all C<once> block as if they had never been called, i.e. on the |
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|
863 | next call they will be reevaluated again. |
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|
864 | |
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|
865 | =cut |
917 | =cut |
866 | |
918 | |
867 | sub once(&) { |
919 | sub keep(&) { |
868 | my $id = $_[0]+0; |
920 | my $id = $_[0]+0; |
869 | |
921 | |
870 | local $frame = $self->{frame_cache}{$id} ||= [$frame]; |
922 | local $frame = $self->{frame_cache}{$id} ||= [$frame]; |
871 | |
923 | |
872 | unless ($frame->[FR_CACHE]) { |
924 | unless ($frame->[FR_CACHE]) { |
… | |
… | |
879 | # clear this frame cache, also for all parents |
931 | # clear this frame cache, also for all parents |
880 | for (my $frame = $frame; $frame; $frame = $frame->[0]) { |
932 | for (my $frame = $frame; $frame; $frame = $frame->[0]) { |
881 | undef $frame->[FR_CACHE]; |
933 | undef $frame->[FR_CACHE]; |
882 | } |
934 | } |
883 | |
935 | |
884 | unless ($self->{term}) { |
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|
885 | use Data::Dump; |
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|
886 | ddx $frame; |
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|
887 | exit; |
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|
888 | } |
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|
889 | |
|
|
890 | $self->recalculate; |
936 | $self->recalculate; |
891 | }); |
937 | }); |
892 | }; |
938 | }; |
893 | |
939 | |
894 | # in scalar context we always return the first original result, which |
940 | # in scalar context we always return the first original result, which |
… | |
… | |
896 | wantarray |
942 | wantarray |
897 | ? @{ $frame->[FR_CACHE] } |
943 | ? @{ $frame->[FR_CACHE] } |
898 | : $frame->[FR_CACHE][0] |
944 | : $frame->[FR_CACHE][0] |
899 | } |
945 | } |
900 | |
946 | |
901 | sub once_again() { |
947 | # sub keep_clear() { |
902 | delete $self->{frame_cache}; |
948 | # delete $self->{frame_cache}; |
903 | } |
949 | # } |
904 | |
950 | |
905 | =back |
951 | =back |
906 | |
952 | |
907 | =cut |
953 | =cut |
908 | |
954 | |
… | |
… | |
921 | |
967 | |
922 | # compiles a parsed expression |
968 | # compiles a parsed expression |
923 | sub set_expr { |
969 | sub set_expr { |
924 | my ($self, $expr) = @_; |
970 | my ($self, $expr) = @_; |
925 | |
971 | |
926 | $self->{root} = []; |
972 | $self->{root} = []; # the outermost frame |
927 | $self->{expr} = $expr; |
973 | $self->{expr} = $expr; |
928 | $self->recalculate; |
974 | $self->recalculate; |
929 | } |
975 | } |
930 | |
976 | |
931 | # takes a hash of sensitivity indicators and installs watchers |
977 | # takes a hash of sensitivity indicators and installs watchers |
… | |
… | |
993 | |
1039 | |
994 | # set environment to evaluate user expression |
1040 | # set environment to evaluate user expression |
995 | |
1041 | |
996 | local $self = $arg_self; |
1042 | local $self = $arg_self; |
997 | local $HOME = $ENV{HOME}; |
1043 | local $HOME = $ENV{HOME}; |
998 | local $frame = []; |
1044 | local $frame = $self->{root}; |
999 | |
1045 | |
1000 | ($x, $y, $w, $h) = $self->background_geometry ($self->{border}); |
1046 | ($x, $y, $w, $h) = $self->background_geometry ($self->{border}); |
1001 | |
1047 | |
1002 | # evaluate user expression |
1048 | # evaluate user expression |
1003 | |
1049 | |