I'm sorry, what is "Goo::Canvas"? I can't find it in the "GTK+ Reference Manual"
On 8/13/08, zentara <[EMAIL PROTECTED]> wrote: > > On Tue, 12 Aug 2008 22:27:28 +0800 > "Lazy Fox" <[EMAIL PROTECTED]> wrote: > > > I want to draw a loopback-able dynamic curve, just like the following > >picture: > >http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/18030.jpg > > > >The curve is keeping going, from left to right. When reach the right > border, > >it will loopback to the left border, and do this again and again. > > > >But, when the curve loopback to the left border, the existent drawing will > >not > >be erased immediately. Instead, the older drawing will be erased step by > >step, > >where the new curve is drawing. > > > >Considering the efficiency. In this case, which widget should I draw on? > >How can I erase the image step by step, > >not erase all of it? Which function should I use? > > I apologize to the c experts for this Perl, :-), but it's so easy for > me to prototype in Perl. Here is an example of what you can do on > the Goo::Canvas. > > I simulated the beat pulse with a weird sine wave, but it should show you > how nice it could work. The axis are a bit extra, but I already had this > example, to show how to invert the y axis direction to get a standard > cartesian > plot, i.e. y increases going up. > I also took the liberty of making a recursive sub call for this demo, but > it > should'nt be hard to feed in real data. Of course, c will be faster, but > it's up to you to port it, if you like it. > > #!/usr/bin/perl -w > use strict; > use warnings; > use Goo::Canvas; > use Gtk2 '-init'; > use Glib qw(TRUE FALSE); > use Gtk2::Gdk::Keysyms; > > my $scale = 1; > > my $window = Gtk2::Window->new('toplevel'); > $window->signal_connect('delete_event' => sub { Gtk2->main_quit; }); > $window->set_size_request(800, 600); > > my $swin = Gtk2::ScrolledWindow->new; > $swin->set_shadow_type('in'); > $window->add($swin); > > my ($cwidth,$cheight)= (1200,1200); > my $canvas = Goo::Canvas->new(); > $canvas->set_size_request(800, 650); > $canvas->set_bounds(0, 0, $cwidth, $cheight); > my $black = Gtk2::Gdk::Color->new (0x0000,0x0000,0x0000); > my $white = Gtk2::Gdk::Color->new (0xFFFF,0xFFFF,0xFFFF); > $canvas->modify_base('normal',$white ); > $swin->add($canvas); > > my $root = $canvas->get_root_item(); > > my ($margin_x,$margin_y) = (100,100); > > my $g = Goo::Canvas::Group->new($root); > $g->scale(1,-1); #reverse direction of y axis, so graphing will be normal > cartesian > $g->translate(0 + $margin_x, -1200 + $margin_y); #notice translations are > reversed > $canvas->scroll_to(0,$cheight); > > # add a background rect filling $g, so button press will be detected > # otherwise $g will be invisible to button-press-event > my $rect = Goo::Canvas::Rect->new( > $g, 0, 0, $cwidth,$cheight, > 'line-width' => 1, > 'stroke-color' => 'white', #invisible on white bg > 'fill-color' => 'white', # must be filled for mouse event sensitivity > ); > > # some key help > my $markup = "<span font_family ='Arial ' > foreground = '#000000' > size = '12000' > weight = 'ultralight'> Keys: 'Z' zoom in, 'z' zoom out, > 's' save a PDF </span>"; > > my $text = Goo::Canvas::Text->new( > $g, > $markup, > -80 , 80 , -1, > 'w', > 'use markup' => 1, > ); > > $text->scale(1,-1); > > > > > $g->signal_connect('button-press-event', > \&on_g_button_press); > > $canvas->signal_connect_after('key_press_event', \&on_key_press); > $canvas->can_focus(TRUE); > $canvas->grab_focus($root); > > &set_axis(); > &plot(); > > $window->show_all(); > > Gtk2->main; > > sub set_axis{ > > # x axis > my $xline = Goo::Canvas::Polyline->new( > $g, TRUE, > [0,0,900,0], > 'stroke-color' => 'black', > 'line-width' => 3, > ); > > #label > my $markup = "<span font_family ='Arial ' > foreground = '#000000' > size = '18000' > weight = 'bold'> X axis Label </span>"; > > my $text = Goo::Canvas::Text->new( > $g, > $markup, > 450 , 80 , -1, > 'center', > 'use markup' => 1, > ); > > $text->scale(1,-1); > > > > for my $x (0..900){ > > if ($x % 100 == 0){ > my $xtick = Goo::Canvas::Polyline->new( > $g, TRUE, > [$x,0,$x,-25], > 'stroke-color' => 'black', > 'line-width' => 3, > ); > > $markup = "<span font_family ='Arial ' > foreground = '#0000ff' > size = '10000' > weight = 'light'> $x </span>"; > > $text = Goo::Canvas::Text->new( > $g, > $markup, > $x-1 , 10 , 1, > 'north-east', > 'use markup' => 1, > 'wrap' => 'char'); > > $text->scale(1,-1); > > > > }elsif ($x % 10 == 0){ > > my $xtick = Goo::Canvas::Polyline->new( > $g, TRUE, > [$x,0,$x,-15], > 'stroke-color' => 'red', > 'line-width' => 1, > ); > > my $markup = "<span font_family ='Arial ' > foreground = '#ff0000' > size = '8000' > weight = 'ultralight'> $x </span>"; > > my $text = Goo::Canvas::Text->new( > $g, > $markup, > $x-1 , 6 , 1, > 'north-east', > 'use markup' => 1, > 'wrap' => 'char'); > > $text->scale(1,-1); > > } > } > > # y axis > my $yline = Goo::Canvas::Polyline->new( > $g, TRUE, > [0,0,0,900], > 'stroke-color' => 'black', > 'line-width' => 3, > ); > > > #label > $markup = "<span font_family ='Arial ' > foreground = '#000000' > size = '18000' > weight = 'bold'> Y axis Label </span>"; > > $text = Goo::Canvas::Text->new( > $g, > $markup, > -70 ,-450 , -1, > 'center', > 'use markup' => 1, > ); > > $text->scale(1,-1); > $text->rotate(-90,-70,-450); > > > for my $y (0..900){ > > if ($y % 100 == 0){ > my $ytick = Goo::Canvas::Polyline->new( > $g, TRUE, > [0,$y,-25,$y], > 'stroke-color' => 'black', > 'line-width' => 3, > ); > > $markup = "<span font_family ='Arial ' > foreground = '#0000ff' > size = '10000' > weight = 'light'> $y </span>"; > > $text = Goo::Canvas::Text->new( > $g, > $markup, > -25 , -$y -8 , -1, > 'north-east', > 'use markup' => 1, > ); > > $text->scale(1,-1); > > > > }elsif ($y % 10 == 0){ > > my $ytick = Goo::Canvas::Polyline->new( > $g, TRUE, > [0,$y,-15,$y], > 'stroke-color' => 'red', > 'line-width' => 1, > ); > > my $markup = "<span font_family ='Arial ' > foreground = '#ff0000' > size = '8000' > weight = 'ultralight'> $y </span>"; > > my $text = Goo::Canvas::Text->new( > $g, > $markup, > -16 , -$y - 6 , -1, > 'north-east', > 'use markup' => 1, > ); > > $text->scale(1,-1); > > } > } > > > } > > sub plot{ > > my $points_ref = [0,300,0,300]; > > my $points = Goo::Canvas::Points->new( $points_ref ); #need 2 points > min > > my $poly = Goo::Canvas::Polyline->new( > $g, FALSE, > undef, # points need to be set after creation > 'stroke-color' => 'green', > 'line-width' => 2, > ); > > #setting after line creation, sets the 'points' property by name > $poly->set(points => $points); > > > my $x = 0; my $y = 0; > > Glib::Timeout->add (100, sub { > $x+= 10; > $y = 300 + rand 100*sin( $x / 500); > > if( $x > 301 ){ > > my $num = $g->find_child ($poly); > $g->remove_child($num); > &plot(); > return FALSE; > } > > > push @$points_ref, $x, $y; > $points = Goo::Canvas::Points->new( $points_ref ); #need 2 > points min > $poly->set(points => $points); > return TRUE; > }); > > } > > sub on_g_button_press { > #print "@_\n"; > my ( $group, $widget, $event ) = @_; > print $widget ,' ',$event->type, ' ','button',' ',$event->button,"\n"; > my ($x,$y) = ($event->x,$event->y); > print "$x $y\n"; > return 0; > } > > sub on_key_press { > # print "@_\n"; > my ( $canvas, $event ) = @_; > # print $event->type,"\n"; > > if ( $event->keyval == $Gtk2::Gdk::Keysyms{Z} ) { > $scale += .1; > $canvas->set_scale($scale); > $canvas->scroll_to(0,$cheight); > } > > if ( $event->keyval == $Gtk2::Gdk::Keysyms{z} ) { > $scale -= .1; > $canvas->set_scale($scale); > $canvas->set_scale($scale); > $canvas->scroll_to(0,$cheight); > } > > if ( $event->keyval == $Gtk2::Gdk::Keysyms{s} ) { > write_pdf($canvas); > } > > # print "key was ", chr( $event->keyval ), "\n"; > > return 0; > } > > > sub write_pdf { > #print "@_\n"; > my $canvas = shift; > print "Write PDF...\n"; > > my $scale = $canvas->get_scale; > print "scale->$scale\n"; > > my $surface = Cairo::PdfSurface->create("$0-$scale.pdf", > $scale*$cwidth, $scale*$cheight); > > my $cr = Cairo::Context->create($surface); > > # needed to save scaled version > $cr->scale($scale, $scale); > > $canvas->render($cr, undef, 1); > $cr->show_page; > print "done\n"; > return TRUE; > } > > __END__ > > > > > zentara > > > > -- > I'm not really a human, but I play one on earth. > http://zentara.net/Remember_How_Lucky_You_Are.html > -- ---------------------------------------------- ┏━━━━━━━━━━━━━━━━━━━━━━━━┓ ┃菩提本无树，明镜亦非台。本来无一物，何处惹尘埃。┃ ┗━━━━━━━━━━━━━━━━━━━━━━━━┛
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