On Mon, 11 Aug 2008 11:57:00 -0700 "Matt Kowalczyk" <matt.kowalczyk@xxxxxxxxx> wrote: >with this one. Is GnomeCanvas something I should look at? > >The solution to only clear the pixels representing the selection clearly >improves performance. > >I'm just a newbie UI developer and wanted to solicit some suggestions as >this is my first day working with GTK and I would hate to overlook a >possibly simple solution to this problem. > >Thanks! I would go with a canvas type widget, because you can make a single rectangle and just redefine it's points as you drag the mouse. I'm sorry I don't have an example for Gnome2::Canvas or the Goo::Canvas, which would be preferrable. I did this in Perl/Tk at http://perlmonks.org?node_id=692998 It scans your directory, makes a thumbnail selection bar, then clicking on a thumbnail, loads the image on a Tk::Canvas. You can then drag-right-click on the image, and it's selected area is automatically copied to another canvas, where it is draggable for you to position. It is sort of a custom montage maker. The whole idea should work in Gnome2::Canvas or Goo::Canvas(my favorite now.). Here is a quick Perl script to do the selection, but copying off the sub-pixbuf is left out. One thing I noticed, is you need to give a transparent fill color, to prevent dragging artifacts being left as unwanted random lines. That seems like a bug. This shouldn't be too hard to convert to c. #!/usr/bin/perl use warnings; use strict; use Gtk2 '-init'; use Gnome2::Canvas; use Glib qw/TRUE FALSE/; my $file = shift || die "Need an image file $!\n"; my ( $dragging, $last_x, $last_y ); # item_move globals my $rect; my $window = Gtk2::Window->new(); $window->set_size_request(450,350); $window->signal_connect('destroy'=>\&delete_event ); my $vbox= Gtk2::VBox->new(FALSE, 1 ); $window->add($vbox); my $scroller = Gtk2::ScrolledWindow->new(); my $canvas = Gnome2::Canvas->new_aa(); $canvas->set_center_scroll_region (FALSE); $scroller->add($canvas); my $hbox= Gtk2::HBox->new(TRUE, 1 ); $vbox->pack_start($hbox,TRUE,TRUE,0); $hbox->set_border_width(2); $hbox->add($scroller); $vbox->pack_start(Gtk2::HSeparator->new, FALSE, FALSE, 0); my $hbox1= Gtk2::HBox->new(FALSE, 1 ); $vbox->pack_end($hbox1,FALSE,FALSE,0); $hbox1->set_border_width(2); my $button = Gtk2::Button->new_from_stock('gtk-quit'); $hbox1->pack_end( $button, FALSE, FALSE, 0 ); $button->signal_connect( clicked => \&delete_event ); my $root = $canvas->root; my $im = Gtk2::Gdk::Pixbuf->new_from_file( $file ); my $image = Gnome2::Canvas::Item->new ($root, 'Gnome2::Canvas::Pixbuf', pixbuf => $im, x => 10, y => 10, width => $im->get_width, height => $im->get_height, anchor => 'nw', ); $canvas->set_scroll_region(0,0,$im->get_width,$im->get_height); $image->lower_to_bottom(); $canvas->signal_connect( "event", \&drag_rect ); $window->show_all(); Gtk2->main(); ################################################ sub delete_event { Gtk2->main_quit; return FALSE; } ############################################# sub drag_rect { my ( $canvas, $event ) = @_; # print "$item $event->type\n"; if ( $event->type eq "button-press" ) { #$canvas->window->set_cursor( Gtk2::Gdk::Cursor->new('fleur') ); my $startx = $event->x; my $starty = $event->y; $dragging = 1; print "start\n"; $rect = Gnome2::Canvas::Item->new ($root, 'Gnome2::Canvas::Rect', x1 => $startx, y1 => $starty, x2 => $startx, y2 => $starty, fill_color_rgba => 0x00000000, outline_color => 'black', width_units => 1.0); } elsif ( $event->type eq "motion-notify" ) { if ($dragging) { my $new_x = $event->x; my $new_y = $event->y; print "dragging\n"; $rect->set(x2 => $new_x, y2 => $new_y); } } elsif ( $event->type eq "button-release" ) { $dragging = 0; print "release\n"; #$rect->destroy; # $canvas->window->set_cursor (undef); } return 0; } __END__ zentara -- I'm not really a human, but I play one on earth. http://zentara.net/Remember_How_Lucky_You_Are.html _______________________________________________ gtk-list mailing list gtk-list@xxxxxxxxx http://mail.gnome.org/mailman/listinfo/gtk-list
