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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 | #:META:X_RESOURCE:%.interval:seconds:minimum time between updates |
6 | |
6 | |
7 | =head1 NAME |
7 | =head1 NAME |
8 | |
8 | |
9 | background - manage terminal background |
9 | background - manage terminal background |
10 | |
10 | |
11 | =head1 SYNOPSIS |
11 | =head1 SYNOPSIS |
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 |
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16 | |
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17 | =head1 QUICK AND DIRTY CHEAT SHEET |
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18 | |
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19 | Just load a random jpeg image and tile the background with it without |
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20 | scaling or anything else: |
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21 | |
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22 | load "/path/to/img.jpg" |
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23 | |
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24 | The same, but use mirroring/reflection instead of tiling: |
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25 | |
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26 | mirror load "/path/to/img.jpg" |
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27 | |
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28 | Load an image and scale it to exactly fill the terminal window: |
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29 | |
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30 | scale keep { load "/path/to/img.jpg" } |
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31 | |
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32 | Implement pseudo-transparency by using a suitably-aligned root pixmap |
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33 | as window background: |
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34 | |
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35 | rootalign root |
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36 | |
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37 | Likewise, but keep a blurred copy: |
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38 | |
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39 | rootalign keep { blur 10, root } |
16 | |
40 | |
17 | =head1 DESCRIPTION |
41 | =head1 DESCRIPTION |
18 | |
42 | |
19 | This extension manages the terminal background by creating a picture that |
43 | This extension manages the terminal background by creating a picture that |
20 | is behind the text, replacing the normal background colour. |
44 | is behind the text, replacing the normal background colour. |
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73 | } else { |
97 | } else { |
74 | return load "$HOME/sunday.png"; |
98 | return load "$HOME/sunday.png"; |
75 | } |
99 | } |
76 | } |
100 | } |
77 | |
101 | |
78 | This expression is evaluated once per hour. It will set F<sunday.png> as |
102 | This inner expression is evaluated once per hour (and whenever the |
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103 | terminal window is resized). It sets F<sunday.png> as background on |
79 | background on Sundays, and F<weekday.png> on all other days. |
104 | Sundays, and F<weekday.png> on all other days. |
80 | |
105 | |
81 | Fortunately, we expect that most expressions will be much simpler, with |
106 | Fortunately, we expect that most expressions will be much simpler, with |
82 | little Perl knowledge needed. |
107 | little Perl knowledge needed. |
83 | |
108 | |
84 | Basically, you always start with a function that "generates" an image |
109 | Basically, you always start with a function that "generates" an image |
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117 | horizontal and vertical dimensions. For example, this halves the image |
142 | horizontal and vertical dimensions. For example, this halves the image |
118 | width and doubles the image height: |
143 | width and doubles the image height: |
119 | |
144 | |
120 | scale 0.5, 2, load "$HOME/mypic.png" |
145 | scale 0.5, 2, load "$HOME/mypic.png" |
121 | |
146 | |
122 | IF you try out these expressions, you might suffer from sluggishness, |
147 | IF you try out these expressions, you might suffer from some sluggishness, |
123 | because each time the terminal is resized, it again loads the PNG image |
148 | because each time the terminal is resized, it loads the PNG image again |
124 | and scales it. Scaling is usually fast, but loading the image can be quite |
149 | and scales it. Scaling is usually fast (and unavoidable), but loading the |
125 | time consuming. This is where C<keep> comes in handy: |
150 | image can be quite time consuming. This is where C<keep> comes in handy: |
126 | |
151 | |
127 | scale 0.5, 2, keep { load "$HOME/mypic.png" } |
152 | scale 0.5, 2, keep { load "$HOME/mypic.png" } |
128 | |
153 | |
129 | The C<keep> operator executes all the statements inside the braces only |
154 | The C<keep> operator executes all the statements inside the braces only |
130 | once, or when it thinks the outcome might change. In other cases it |
155 | once, or when it thinks the outcome might change. In other cases it |
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155 | |
180 | |
156 | This one first takes a snapshot of the screen background image, and then |
181 | This one first takes a snapshot of the screen background image, and then |
157 | moves it to the upper left corner of the screen (as opposed to the upper |
182 | moves it to the upper left corner of the screen (as opposed to the upper |
158 | left corner of the terminal window)- the result is pseudo-transparency: |
183 | left corner of the terminal window)- the result is pseudo-transparency: |
159 | the image seems to be static while the window is moved around. |
184 | the image seems to be static while the window is moved around. |
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185 | |
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186 | =head2 COLOUR SPECIFICATIONS |
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187 | |
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188 | Whenever an operator expects a "colour", then this can be specified in one |
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189 | of two ways: Either as string with an X11 colour specification, such as: |
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190 | |
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191 | "red" # named colour |
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192 | "#f00" # simple rgb |
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193 | "[50]red" # red with 50% alpha |
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194 | "TekHVC:300/50/50" # anything goes |
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195 | |
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196 | OR as an array reference with one, three or four components: |
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197 | |
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198 | [0.5] # 50% gray, 100% alpha |
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199 | [0.5, 0, 0] # dark red, no green or blur, 100% alpha |
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200 | [0.5, 0, 0, 0.7] # same with explicit 70% alpha |
160 | |
201 | |
161 | =head2 CACHING AND SENSITIVITY |
202 | =head2 CACHING AND SENSITIVITY |
162 | |
203 | |
163 | Since some operations (such as C<load> and C<blur>) can take a long time, |
204 | Since some operations (such as C<load> and C<blur>) can take a long time, |
164 | caching results can be very important for a smooth operation. Caching can |
205 | caching results can be very important for a smooth operation. Caching can |
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172 | ... }>. The C<keep> operator takes a block of multiple statements enclosed |
213 | ... }>. The C<keep> operator takes a block of multiple statements enclosed |
173 | by C<{}> and keeps the return value in memory. |
214 | by C<{}> and keeps the return value in memory. |
174 | |
215 | |
175 | An expression can be "sensitive" to various external events, such as |
216 | An expression can be "sensitive" to various external events, such as |
176 | scaling or moving the window, root background changes and timers. Simply |
217 | scaling or moving the window, root background changes and timers. Simply |
177 | using an expression (such as C<scale> without parameters) that depend on |
218 | using an expression (such as C<scale> without parameters) that depends on |
178 | certain changing values (called "variables"), or using those variables |
219 | certain changing values (called "variables"), or using those variables |
179 | directly, will make an expression sensitive to these events - for example, |
220 | directly, will make an expression sensitive to these events - for example, |
180 | using C<scale> or C<TW> will make the expression sensitive to the terminal |
221 | using C<scale> or C<TW> will make the expression sensitive to the terminal |
181 | size, and thus to resizing events. |
222 | size, and thus to resizing events. |
182 | |
223 | |
183 | When such an event happens, C<keep> will automatically trigger a |
224 | When such an event happens, C<keep> will automatically trigger a |
184 | reevaluation of the whole expression with the new value of the expression. |
225 | reevaluation of the whole expression with the new value of the expression. |
185 | |
226 | |
186 | C<keep> is most useful for expensive operations, such as C<blur>: |
227 | C<keep> is most useful for expensive operations, such as C<blur>: |
187 | |
228 | |
188 | rootalign once { blur 20, root } |
229 | rootalign keep { blur 20, root } |
189 | |
230 | |
190 | This makes a blurred copy of the root background once, and on subsequent |
231 | This makes a blurred copy of the root background once, and on subsequent |
191 | calls, just root-aligns it. Since C<blur> is usually quite slow and |
232 | calls, just root-aligns it. Since C<blur> is usually quite slow and |
192 | C<rootalign> is quite fast, this trades extra memory (for the cached |
233 | C<rootalign> is quite fast, this trades extra memory (for the cached |
193 | blurred pixmap) with speed (blur only needs to be redone when root |
234 | blurred pixmap) with speed (blur only needs to be redone when root |
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272 | uses it), then the in-memory copy us returned instead. |
313 | uses it), then the in-memory copy us returned instead. |
273 | |
314 | |
274 | =item load_uc $path |
315 | =item load_uc $path |
275 | |
316 | |
276 | Load uncached - same as load, but does not cache the image, which means it |
317 | Load uncached - same as load, but does not cache the image, which means it |
277 | is I<always> loaded from the filesystem again. |
318 | is I<always> loaded from the filesystem again, even if another copy of it |
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319 | is in memory at the time. |
278 | |
320 | |
279 | =cut |
321 | =cut |
280 | |
322 | |
281 | sub load_uc($) { |
323 | sub load_uc($) { |
282 | $self->new_img_from_file ($path) |
324 | $self->new_img_from_file ($_[0]) |
283 | } |
325 | } |
284 | |
326 | |
285 | sub load($) { |
327 | sub load($) { |
286 | my ($path) = @_; |
328 | my ($path) = @_; |
287 | |
329 | |
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380 | for @_; |
422 | for @_; |
381 | |
423 | |
382 | $base |
424 | $base |
383 | } |
425 | } |
384 | |
426 | |
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427 | =back |
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428 | |
385 | =head2 TILING MODES |
429 | =head2 TILING MODES |
386 | |
430 | |
387 | The following operators modify the tiling mode of an image, that is, the |
431 | The following operators modify the tiling mode of an image, that is, the |
388 | way that pixels outside the image area are painted when the image is used. |
432 | way that pixels outside the image area are painted when the image is used. |
389 | |
433 | |
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491 | |
535 | |
492 | move -TX, -TY, keep { load "mybg.png" } |
536 | move -TX, -TY, keep { load "mybg.png" } |
493 | |
537 | |
494 | =item TW |
538 | =item TW |
495 | |
539 | |
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540 | =item TH |
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541 | |
496 | Return the width (C<TW>) and height (C<TH>) of the terminal window (the |
542 | Return the width (C<TW>) and height (C<TH>) of the terminal window (the |
497 | terminal window is the full window by default, and the character area only |
543 | terminal window is the full window by default, and the character area only |
498 | when in border-respect mode). |
544 | when in border-respect mode). |
499 | |
545 | |
500 | Using these functions make your expression sensitive to window resizes. |
546 | Using these functions make your expression sensitive to window resizes. |
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567 | Clips an image to the given rectangle. If the rectangle is outside the |
613 | Clips an image to the given rectangle. If the rectangle is outside the |
568 | image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is |
614 | image area (e.g. when C<$x> or C<$y> are negative) or the rectangle is |
569 | larger than the image, then the tiling mode defines how the extra pixels |
615 | larger than the image, then the tiling mode defines how the extra pixels |
570 | will be filled. |
616 | will be filled. |
571 | |
617 | |
572 | If C<$x> an C<$y> are missing, then C<0> is assumed for both. |
618 | If C<$x> and C<$y> are missing, then C<0> is assumed for both. |
573 | |
619 | |
574 | If C<$width> and C<$height> are missing, then the window size will be |
620 | If C<$width> and C<$height> are missing, then the window size will be |
575 | assumed. |
621 | assumed. |
576 | |
622 | |
577 | Example: load an image, blur it, and clip it to the window size to save |
623 | Example: load an image, blur it, and clip it to the window size to save |
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753 | |
799 | |
754 | The following operators change the pixels of the image. |
800 | The following operators change the pixels of the image. |
755 | |
801 | |
756 | =over 4 |
802 | =over 4 |
757 | |
803 | |
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804 | =item tint $color, $img |
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805 | |
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806 | Tints the image in the given colour. |
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807 | |
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808 | Example: tint the image red. |
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809 | |
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810 | tint "red", load "rgb.png" |
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811 | |
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812 | Example: the same, but specify the colour by component. |
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813 | |
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814 | tint [1, 0, 0], load "rgb.png" |
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815 | |
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816 | =cut |
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817 | |
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818 | sub tint($$) { |
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819 | $_[1]->tint ($_[0]) |
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820 | } |
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821 | |
758 | =item contrast $factor, $img |
822 | =item contrast $factor, $img |
759 | |
823 | |
760 | =item contrast $r, $g, $b, $img |
824 | =item contrast $r, $g, $b, $img |
761 | |
825 | |
762 | =item contrast $r, $g, $b, $a, $img |
826 | =item contrast $r, $g, $b, $a, $img |
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791 | latter in a white picture. |
855 | latter in a white picture. |
792 | |
856 | |
793 | Due to idiosyncrasies in the underlying XRender extension, biases less |
857 | Due to idiosyncrasies in the underlying XRender extension, biases less |
794 | than zero can be I<very> slow. |
858 | than zero can be I<very> slow. |
795 | |
859 | |
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860 | You can also try the experimental(!) C<muladd> operator. |
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861 | |
796 | =cut |
862 | =cut |
797 | |
863 | |
798 | sub contrast($$;$$;$) { |
864 | sub contrast($$;$$;$) { |
799 | my $img = pop; |
865 | my $img = pop; |
800 | my ($r, $g, $b, $a) = @_; |
866 | my ($r, $g, $b, $a) = @_; |
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815 | $a = 1 if @_ < 4; |
881 | $a = 1 if @_ < 4; |
816 | |
882 | |
817 | $img = $img->clone; |
883 | $img = $img->clone; |
818 | $img->brightness ($r, $g, $b, $a); |
884 | $img->brightness ($r, $g, $b, $a); |
819 | $img |
885 | $img |
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886 | } |
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887 | |
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888 | =item muladd $mul, $add, $img # EXPERIMENTAL |
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889 | |
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890 | First multiplies the pixels by C<$mul>, then adds C<$add>. This can be used |
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891 | to implement brightness and contrast at the same time, with a wider value |
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892 | range than contrast and brightness operators. |
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893 | |
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894 | Due to numerous bugs in XRender implementations, it can also introduce a |
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895 | number of visual artifacts. |
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896 | |
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897 | Example: increase contrast by a factor of C<$c> without changing image |
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898 | brightness too much. |
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899 | |
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900 | muladd $c, (1 - $c) * 0.5, $img |
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901 | |
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902 | =cut |
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903 | |
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904 | sub muladd($$$) { |
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905 | $_[2]->muladd ($_[0], $_[1]) |
820 | } |
906 | } |
821 | |
907 | |
822 | =item blur $radius, $img |
908 | =item blur $radius, $img |
823 | |
909 | |
824 | =item blur $radius_horz, $radius_vert, $img |
910 | =item blur $radius_horz, $radius_vert, $img |
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845 | Anything that didn't fit any of the other categories, even after applying |
931 | Anything that didn't fit any of the other categories, even after applying |
846 | force and closing our eyes. |
932 | force and closing our eyes. |
847 | |
933 | |
848 | =over 4 |
934 | =over 4 |
849 | |
935 | |
850 | =item once { ... } |
936 | =item keep { ... } |
851 | |
937 | |
852 | This function takes a code block as argument, that is, one or more |
938 | This operator takes a code block as argument, that is, one or more |
853 | statements enclosed by braces. |
939 | statements enclosed by braces. |
854 | |
940 | |
855 | The trick is that this code block is only evaluated once - future calls |
941 | The trick is that this code block is only evaluated when the outcome |
856 | will simply return the original image (yes, it should only be used with |
942 | changes - on other calls the C<keep> simply returns the image it computed |
857 | images). |
943 | previously (yes, it should only be used with images). Or in other words, |
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944 | C<keep> I<caches> the result of the code block so it doesn't need to be |
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945 | computed again. |
858 | |
946 | |
859 | This can be extremely useful to avoid redoing the same slow operations |
947 | This can be extremely useful to avoid redoing slow operations - for |
860 | again and again- for example, if your background expression takes the root |
948 | example, if your background expression takes the root background, blurs it |
861 | background, blurs it and then root-aligns it it would have to blur the |
949 | and then root-aligns it it would have to blur the root background on every |
862 | root background on every window move or resize. |
950 | window move or resize. |
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951 | |
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952 | Another example is C<load>, which can be quite slow. |
863 | |
953 | |
864 | In fact, urxvt itself encloses the whole expression in some kind of |
954 | In fact, urxvt itself encloses the whole expression in some kind of |
865 | C<once> block so it only is reevaluated as required. |
955 | C<keep> block so it only is reevaluated as required. |
866 | |
956 | |
867 | Putting the blur into a C<once> block will make sure the blur is only done |
957 | Putting the blur into a C<keep> block will make sure the blur is only done |
868 | once: |
958 | once, while the C<rootalign> is still done each time the window moves. |
869 | |
959 | |
870 | rootlign once { blur 10, root } |
960 | rootalign keep { blur 10, root } |
871 | |
961 | |
872 | This leaves the question of how to force reevaluation of the block, |
962 | This leaves the question of how to force reevaluation of the block, |
873 | in case the root background changes: If expression inside the block |
963 | in case the root background changes: If expression inside the block |
874 | is sensitive to some event (root background changes, window geometry |
964 | is sensitive to some event (root background changes, window geometry |
875 | changes), then it will be reevaluated automatically as needed. |
965 | changes), then it will be reevaluated automatically as needed. |
876 | |
966 | |
877 | =item once_again |
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878 | |
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879 | Resets all C<once> block as if they had never been called, i.e. on the |
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880 | next call they will be reevaluated again. |
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881 | |
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882 | =cut |
967 | =cut |
883 | |
968 | |
884 | sub once(&) { |
969 | sub keep(&) { |
885 | my $id = $_[0]+0; |
970 | my $id = $_[0]+0; |
886 | |
971 | |
887 | local $frame = $self->{frame_cache}{$id} ||= [$frame]; |
972 | local $frame = $self->{frame_cache}{$id} ||= [$frame]; |
888 | |
973 | |
889 | unless ($frame->[FR_CACHE]) { |
974 | unless ($frame->[FR_CACHE]) { |
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907 | wantarray |
992 | wantarray |
908 | ? @{ $frame->[FR_CACHE] } |
993 | ? @{ $frame->[FR_CACHE] } |
909 | : $frame->[FR_CACHE][0] |
994 | : $frame->[FR_CACHE][0] |
910 | } |
995 | } |
911 | |
996 | |
912 | sub once_again() { |
997 | # sub keep_clear() { |
913 | delete $self->{frame_cache}; |
998 | # delete $self->{frame_cache}; |
914 | } |
999 | # } |
915 | |
1000 | |
916 | =back |
1001 | =back |
917 | |
1002 | |
918 | =cut |
1003 | =cut |
919 | |
1004 | |
… | |
… | |
932 | |
1017 | |
933 | # compiles a parsed expression |
1018 | # compiles a parsed expression |
934 | sub set_expr { |
1019 | sub set_expr { |
935 | my ($self, $expr) = @_; |
1020 | my ($self, $expr) = @_; |
936 | |
1021 | |
937 | $self->{root} = []; |
1022 | $self->{root} = []; # the outermost frame |
938 | $self->{expr} = $expr; |
1023 | $self->{expr} = $expr; |
939 | $self->recalculate; |
1024 | $self->recalculate; |
940 | } |
1025 | } |
941 | |
1026 | |
942 | # takes a hash of sensitivity indicators and installs watchers |
1027 | # takes a hash of sensitivity indicators and installs watchers |
… | |
… | |
1004 | |
1089 | |
1005 | # set environment to evaluate user expression |
1090 | # set environment to evaluate user expression |
1006 | |
1091 | |
1007 | local $self = $arg_self; |
1092 | local $self = $arg_self; |
1008 | local $HOME = $ENV{HOME}; |
1093 | local $HOME = $ENV{HOME}; |
1009 | local $frame = []; |
1094 | local $frame = $self->{root}; |
1010 | |
1095 | |
1011 | ($x, $y, $w, $h) = $self->background_geometry ($self->{border}); |
1096 | ($x, $y, $w, $h) = $self->background_geometry ($self->{border}); |
1012 | |
1097 | |
1013 | # evaluate user expression |
1098 | # evaluate user expression |
1014 | |
1099 | |