--- rxvt-unicode/src/perl/background 2012/06/08 20:23:09 1.36 +++ rxvt-unicode/src/perl/background 2012/06/10 11:53:32 1.45 @@ -5,14 +5,16 @@ #TODO: once, rootalign -=head1 background - manage terminal background +=head1 NAME -=head2 SYNOPSIS + background - manage terminal background + +=head1 SYNOPSIS urxvt --background-expr 'background expression' --background-border -=head2 DESCRIPTION +=head1 DESCRIPTION This extension manages the terminal background by creating a picture that is behind the text, replacing the normal background colour. @@ -32,7 +34,7 @@ URxvt.background-expr: scale load "/path/to/mybg.png" -=head2 THEORY OF OPERATION +=head1 THEORY OF OPERATION At startup, just before the window is mapped for the first time, the expression is evaluated and must yield an image. The image is then @@ -59,7 +61,7 @@ example. That ensures that the picture always fills the terminal, even after it's size changes. -=head3 EXPRESSIONS +=head2 EXPRESSIONS Expressions are normal Perl expressions, in fact, they are Perl blocks - which means you could use multiple lines and statements: @@ -72,7 +74,7 @@ } This expression gets evaluated once per hour. It will set F as -background on sundays, and F on all other days. +background on Sundays, and F on all other days. Fortunately, we expect that most expressions will be much simpler, with little Perl knowledge needed. @@ -99,9 +101,10 @@ Many operators also allow some parameters preceding the input image that modify its behaviour. For example, C without any additional arguments scales the image to size of the terminal window. If you specify -an additional argument, it uses it as a percentage: +an additional argument, it uses it as a scale factor (multiply by 100 to +get a percentage): - scale 200, load "$HOME/mypic.png" + scale 2, load "$HOME/mypic.png" This enlarges the image by a factor of 2 (200%). As you can see, C has now two arguments, the C<200> and the C expression, while @@ -112,20 +115,67 @@ horizontal and vertical dimensions. For example, this halves the image width and doubles the image height: - scale 50, 200, load "$HOME/mypic.png" + scale 0.5, 2, load "$HOME/mypic.png" + +Other effects than scalign are also readily available, for exmaple, you can +tile the image to fill the whole window, instead of resizing it: + + tile load "$HOME/mypic.png" + +In fact, images returned by C are in C mode by default, so the C operator +is kind of superfluous. + +Another common effect is to mirror the image, so that the same edges touch: + + mirror load "$HOME/mypic.png" + +This is also a typical background expression: + + rootalign root + +It first takes a snapshot of the screen background image, and then +moves it to the upper left corner of the screen - the result is +pseudo-transparency, as the image seems to be static while the window is +moved around. + +=head2 CYCLES AND CACHING + +As has been mentioned before, the expression might be evaluated multiple +times. Each time the expression is reevaluated, a new cycle is said to +have begun. Many operators cache their results till the next cycle. + +For example, the C operator keeps a copy of the image. If it is +asked to load the same image on the next cycle it will not load it again, +but return the cached copy. + +This only works for one cycle though, so as long as you load the same +image every time, it will always be cached, but when you load a different +image, it will forget about the first one. + +This allows you to either speed things up by keeping multiple images in +memory, or comserve memory by loading images more often. -TODO +For example, you can keep two images in memory and use a random one like +this: -=head3 CYCLES AND CACHING + my $img1 = load "img1.png"; + my $img2 = load "img2.png"; + (0.5 > rand) ? $img1 : $img2 -TODO +Since both images are "loaded" every time the expression is evaluated, +they are always kept in memory. Contrast this version: -Each time the expression is reevaluated, a new cycle is said to have begun. Many operators -cache their results till the next cycle. For example + my $path1 = "img1.png"; + my $path2 = "img2.png"; + load ((0.5 > rand) ? $path1 : $path2) -=head2 REFERENCE +Here, a path is selected randomly, and load is only called for one image, +so keeps only one image in memory. If, on the next evaluation, luck +decides to use the other path, then it will have to load that image again. -=head3 COMMAND LINE SWITCHES +=head1 REFERENCE + +=head2 COMMAND LINE SWITCHES =over 4 @@ -145,19 +195,6 @@ =cut -our $EXPR;#d# -#$EXPR = 'move W * 0.1, -H * 0.1, resize W * 0.5, H * 0.5, repeat_none load "opensource.png"'; -$EXPR = 'move -TX, -TY, load "argb.png"'; -#$EXPR = ' -# rotate W, H, 50, 50, counter 1/59.95, repeat_mirror, -# clip X, Y, W, H, repeat_mirror, -# load "/root/pix/das_fette_schwein.jpg" -#'; -#$EXPR = 'solid "red"'; -#$EXPR = 'blur root, 10, 10' -#$EXPR = 'blur move (root, -x, -y), 5, 5' -#resize load "/root/pix/das_fette_schwein.jpg", w, h - our $HOME; our ($self, $old, $new); our ($x, $y, $w, $h); @@ -168,6 +205,8 @@ { package urxvt::bgdsl; # background language + use List::Util qw(min max sum shuffle); + =head2 PROVIDERS/GENERATORS These functions provide an image, by loading it from disk, grabbing it @@ -213,12 +252,12 @@ Creates a new image and completely fills it with the given colour. The image is set to tiling mode. -If <$width> and C<$height> are omitted, it creates a 1x1 image, which is +If C<$width> and C<$height> are omitted, it creates a 1x1 image, which is useful for solid backgrounds or for use in filtering effects. =cut - sub solid($$;$) { + sub solid($;$$) { my $colour = pop; my $img = $self->new_img (urxvt::PictStandardARGB32, $_[0] || 1, $_[1] || 1); @@ -226,90 +265,15 @@ $img } -=back - -=head2 VARIABLES - -The following functions provide variable data such as the terminal -window dimensions. Most of them make your expression sensitive to some -events, for example using C (terminal width) means your expression is -evaluated again when the terminal is resized. - -=over 4 - -=item TX - -=item TY - -Return the X and Y coordinates of the terminal window (the terminal -window is the full window by default, and the character area only when in -border-respect mode). - -Using these functions make your expression sensitive to window moves. - -These functions are mainly useful to align images to the root window. - -Example: load an image and align it so it looks as if anchored to the -background. - - move -TX, -TY, load "mybg.png" - -=item TW - -Return the width (C) and height (C) of the terminal window (the -terminal window is the full window by default, and the character area only -when in border-respect mode). - -Using these functions make your expression sensitive to window resizes. - -These functions are mainly useful to scale images, or to clip images to -the window size to conserve memory. - -Example: take the screen background, clip it to the window size, blur it a -bit, align it to the window position and use it as background. - - clip move -TX, -TY, blur 5, root - -=cut - - sub TX() { $new->{position_sensitive} = 1; $x } - sub TY() { $new->{position_sensitive} = 1; $y } - sub TW() { $new->{size_sensitive} = 1; $w } - sub TH() { $new->{size_sensitive} = 1; $h } - -=item now - -Returns the current time as (fractional) seconds since the epoch. - -Using this expression does I make your expression sensitive to time, -but the next two functions do. - -=item again $seconds - -When this function is used the expression will be reevaluated again in -C<$seconds> seconds. - -Example: load some image and rotate it according to the time of day (as if it were -the hour pointer of a clock). Update this image every minute. - - again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png" - -=item counter $seconds +=item clone $img -Like C, but also returns an increasing counter value, starting at -0, which might be useful for some simple animation effects. +Returns an exact copy of the image. This is useful if you want to have +multiple copies of the same image to apply different effects to. =cut - sub now() { urxvt::NOW } - - sub again($) { - $new->{again} = $_[0]; - } - - sub counter($) { - $new->{again} = $_[0]; - $self->{counter} + 0 + sub clone($) { + $_[0]->clone } =back @@ -396,22 +360,99 @@ =back -=head2 PIXEL OPERATORS +=head2 VARIABLE VALUES -The following operators modify the image pixels in various ways. +The following functions provide variable data such as the terminal window +dimensions. They are not (Perl-) variables, they just return stuff that +varies. Most of them make your expression sensitive to some events, for +example using C (terminal width) means your expression is evaluated +again when the terminal is resized. =over 4 -=item clone $img +=item TX + +=item TY -Returns an exact copy of the image. +Return the X and Y coordinates of the terminal window (the terminal +window is the full window by default, and the character area only when in +border-respect mode). + +Using these functions make your expression sensitive to window moves. + +These functions are mainly useful to align images to the root window. + +Example: load an image and align it so it looks as if anchored to the +background. + + move -TX, -TY, load "mybg.png" + +=item TW + +Return the width (C) and height (C) of the terminal window (the +terminal window is the full window by default, and the character area only +when in border-respect mode). + +Using these functions make your expression sensitive to window resizes. + +These functions are mainly useful to scale images, or to clip images to +the window size to conserve memory. + +Example: take the screen background, clip it to the window size, blur it a +bit, align it to the window position and use it as background. + + clip move -TX, -TY, blur 5, root =cut - sub clone($) { - $_[0]->clone + sub TX() { $new->{position_sensitive} = 1; $x } + sub TY() { $new->{position_sensitive} = 1; $y } + sub TW() { $new->{size_sensitive} = 1; $w } + sub TH() { $new->{size_sensitive} = 1; $h } + +=item now + +Returns the current time as (fractional) seconds since the epoch. + +Using this expression does I make your expression sensitive to time, +but the next two functions do. + +=item again $seconds + +When this function is used the expression will be reevaluated again in +C<$seconds> seconds. + +Example: load some image and rotate it according to the time of day (as if it were +the hour pointer of a clock). Update this image every minute. + + again 60; rotate TW, TH, 50, 50, (now % 86400) * -720 / 86400, scale load "myclock.png" + +=item counter $seconds + +Like C, but also returns an increasing counter value, starting at +0, which might be useful for some simple animation effects. + +=cut + + sub now() { urxvt::NOW } + + sub again($) { + $new->{again} = $_[0]; } + sub counter($) { + $new->{again} = $_[0]; + $self->{counter} + 0 + } + +=back + +=head2 SHAPE CHANGING OPERATORS + +The following operators modify the shape, size or position of the image. + +=over 4 + =item clip $img =item clip $width, $height, $img @@ -444,31 +485,45 @@ =item scale $img -=item scale $size_percent, $img +=item scale $size_factor, $img -=item scale $width_percent, $height_percent, $img +=item scale $width_factor, $height_factor, $img -Scales the image by the given percentages in horizontal -(C<$width_percent>) and vertical (C<$height_percent>) direction. +Scales the image by the given factors in horizontal +(C<$width>) and vertical (C<$height>) direction. -If only one percentage is give, it is used for both directions. +If only one factor is give, it is used for both directions. -If no percentages are given, scales the image to the window size without +If no factors are given, scales the image to the window size without keeping aspect. =item resize $width, $height, $img Resizes the image to exactly C<$width> times C<$height> pixels. -=cut +=item fit $img + +=item fit $width, $height, $img + +Fits the image into the given C<$width> and C<$height> without changing +aspect, or the terminal size. That means it will be shrunk or grown until +the whole image fits into the given area, possibly leaving borders. -#TODO: maximise, maximise_fill? +=item cover $img + +=item cover $width, $height, $img + +Similar to C, but shrinks or grows until all of the area is covered +by the image, so instead of potentially leaving borders, it will cut off +image data that doesn't fit. + +=cut sub scale($;$;$) { my $img = pop; - @_ == 2 ? $img->scale ($_[0] * $img->w * 0.01, $_[1] * $img->h * 0.01) - : @_ ? $img->scale ($_[0] * $img->w * 0.01, $_[0] * $img->h * 0.01) + @_ == 2 ? $img->scale ($_[0] * $img->w, $_[1] * $img->h) + : @_ ? $img->scale ($_[0] * $img->w, $_[0] * $img->h) : $img->scale (TW, TH) } @@ -477,6 +532,20 @@ $img->scale ($_[0], $_[1]) } + sub fit($;$$) { + my $img = pop; + my $w = ($_[0] || TW) / $img->w; + my $h = ($_[1] || TH) / $img->h; + scale +(min $w, $h), $img + } + + sub cover($;$$) { + my $img = pop; + my $w = ($_[0] || TW) / $img->w; + my $h = ($_[1] || TH) / $img->h; + scale +(max $w, $h), $img + } + =item move $dx, $dy, $img Moves the image by C<$dx> pixels in the horizontal, and C<$dy> pixels in @@ -486,6 +555,14 @@ move 20, 30, ... +=item center $img + +=item center $width, $height, $img + +Centers the image, i.e. the center of the image is moved to the center of +the terminal window (or the box specified by C<$width> and C<$height> if +given). + =item rootalign $img Moves the image so that it appears glued to the screen as opposed to the @@ -510,10 +587,26 @@ $img } + sub center($;$$) { + my $img = pop; + my $w = $_[0] || TW; + my $h = $_[0] || TH; + + move 0.5 * ($w - $img->w), 0.5 * ($h - $img->h), $img + } + sub rootalign($) { move -TX, -TY, $_[0] } +=back + +=head2 COLOUR MODIFICATIONS + +The following operators change the pixels of the image. + +=over 4 + =item contrast $factor, $img =item contrast $r, $g, $b, $img @@ -522,12 +615,36 @@ Adjusts the I of an image. -=item brightness $factor, $img +The first form applies a single C<$factor> to red, green and blue, the +second form applies separate factors to each colour channel, and the last +form includes the alpha channel. + +Values from 0 to 1 lower the contrast, values higher than 1 increase the +contrast. + +Due to limitations in the underlying XRender extension, lowering contrast +also reduces brightness, while increasing contrast currently also +increases brightness. + +=item brightness $bias, $img =item brightness $r, $g, $b, $img =item brightness $r, $g, $b, $a, $img +Adjusts the brightness of an image. + +The first form applies a single C<$bias> to red, green and blue, the +second form applies separate biases to each colour channel, and the last +form includes the alpha channel. + +Values less than 0 reduce brightness, while values larger than 0 increase +it. Useful range is from -1 to 1 - the former results in a black, the +latter in a white picture. + +Due to idiosynchrasies in the underlying XRender extension, biases less +than zero can be I slow. + =cut sub contrast($$;$$;$) { @@ -538,7 +655,7 @@ $a = 1 if @_ < 5; $img = $img->clone; -# $img->contrast ($r, $g, $b, $a); + $img->contrast ($r, $g, $b, $a); $img } @@ -554,18 +671,45 @@ $img } +=item blur $radius, $img + +=item blur $radius_horz, $radius_vert, $img + +Gaussian-blurs the image with (roughly) C<$radius> pixel radius. The radii +can also be specified separately. + +Blurring is often I slow, at least compared or other +operators. Larger blur radii are slower than smaller ones, too, so if you +don't want to freeze your screen for long times, start experimenting with +low values for radius (<5). + +=cut + sub blur($$;$) { my $img = pop; $img->blur ($_[0], @_ >= 2 ? $_[1] : $_[0]) } +=item rotate $new_width, $new_height, $center_x, $center_y, $degrees + +Rotates the image by C<$degrees> degrees, counter-clockwise, around the +pointer at C<$center_x> and C<$center_y> (specified as factor of image +width/height), generating a new image with width C<$new_width> and height +C<$new_height>. + +#TODO# new width, height, maybe more operators? + +Example: rotate the image by 90 degrees + +=cut + sub rotate($$$$$$) { my $img = pop; $img->rotate ( $_[0], $_[1], - $_[2] * $img->w * .01, - $_[3] * $img->h * .01, + $_[2] * $img->w, + $_[3] * $img->h, $_[4] * (3.14159265 / 180), ) }