NAME
    Gtk3::ImageView - Image viewer widget for Gtk3

VERSION
    9

SYNOPSIS
     use Gtk3::ImageView;
     Gtk3->init;

     $window = Gtk3::Window->new();

     $view = Gtk3::ImageView->new;
     $view->set_pixbuf($pixbuf, TRUE);
     $window->add($view);

     $window->show_all;

DESCRIPTION
    The Gtk3::ImageView widget allows the user to zoom, pan and select the
    specified image and provides hooks to allow additional tools, e.g.
    painter, to be created and used.

    Gtk3::ImageView is a Gtk3 port of Gtk2::ImageView.

    To discuss Gtk3::ImageView or gtk3-perl, ask questions and flame/praise
    the authors, join gtk-perl-list@gnome.org at lists.gnome.org.

SUBROUTINES/METHODS
  $view->set_pixbuf( $pixbuf, $zoom_to_fit )
    Defines the image to view. The optional zoom_to_fit parameter specifies
    whether to zoom to fit the image or not.

  $view->get_pixbuf
    Returns the image currently being viewed.

  $view->get_pixbuf_size
    Returns a hash of containing the size of the current image in width and
    height keys.

  $view->set_zoom($zoom)
    Specifies the zoom level.

  $view->get_zoom
    Returns the current zoom level.

  $view->set_zoom_to_fit($zoom_to_fit, $limit)
    Specifies whether to zoom to fit or not. If limit is defined, such
    automatic zoom will not zoom more than it. If the limit is undefined,
    the previously set limit is used, initially it's unlimited.

  $view->zoom_to_box( $box, $additional_factor )
    Specifies a box to zoom to, including an additional zoom factor

  $view->zoom_to_selection($context_factor)
    Zooms to the current selection, plus an addition zoom factor. Shortcut
    for

     $view->zoom_to_box( $view->get_selection, $context_factor );

  $view->get_zoom_to_fit
    Returns whether the view is currently zoom to fit or not.

  $view->zoom_in
    Increases the current zoom by "zoom-step" times (defaults to 2).

  $view->zoom_out
    Decreases the current zoom by "zoom-step" times (defaults to 2).

  $view->zoom_to_fit
    Shortcut for

     $view->set_zoom_to_fit(TRUE);

  $view->set_fitting( $value )
    Shortcut for

     $view->set_zoom_to_fit($value, 1);

    which means that it won't stretch a small image to a large window.
    Provided (despite the ambiguous name) for compatibility with
    Gtk2::ImageView.

  $view->set_offset( $x, $y )
    Set the current view offset (i.e. pan position).

  $view->set_offset
    Returns the current view offset (i.e. pan position).

  $view->get_viewport
    Returns a hash containing the position and size of the current viewport.

  $view->set_tool
    Set the current tool (i.e. mode) - an object of a subclass of
    "Gtk3::ImageView::Tool".

    Here are some known subclasses of it:

    *
     "Gtk3::ImageView::Tool::Dragger" allows the image to be dragged when
     zoomed.

    *
     "Gtk3::ImageView::Tool::Selector" allows the user to select a
     rectangular area of the image.

    *
     "Gtk3::ImageView::Tool::SelectorDragger" selects or drags with
     different mouse buttons.

    Don't rely too much on how Tool currently interacts with ImageView.

  $view->get_tool
    Returns the current tool (i.e. mode).

  $view->set_selection($selection)
    Set the current selection as a hash of position and size.

  $view->get_selection
    Returns the current selection as a hash of position and size.

  $view->set_resolution_ratio($ratio)
    Set the ratio of the resolutions in the x and y directions, allowing
    images with non-square pixels to be correctly displayed.

  $view->get_resolution_ratio
    Returns the current resolution ratio.

  $view->set_interpolation
    The interpolation method to use, from "cairo_filter_t"
    <https://www.cairographics.org/manual/cairo-cairo-pattern-t.html#cairo-f
    ilter-t> type. Possible values are lowercase strings like "nearest". To
    use different interpolation depending on zoom, set it in the
    "zoom-changed" signal.

  $view->get_interpolation
    Returns the current interpolation method.

DIAGNOSTICS
CONFIGURATION AND ENVIRONMENT
DEPENDENCIES
INCOMPATIBILITIES
  Porting from Gtk2::ImageView
    *
     "set_from_pixbuf()" was renamed to "set_pixbuf()" and now its second
     argument means "zoom_to_fit()" instead of "set_fitting()".

    *
     "set_fitting(TRUE)" used to be the default, now you need to call it
     explicitly if you want that behavior. However, once it's called, new
     calls to "set_from_pixbuf()" won't reset it, see "set_zoom_to_fit()"
     for more details..

    *
     Drag and drop now can be triggered by subscribing to "dnd-start"
     signal, and calling "$view->drag_begin_with_coordinates()" from the
     handler. "drag_source_set()" won't work.

    *
     "Gtk2::ImageView::ScrollWin" replacement is not yet implemented.

    *
     "set_transp()" is now available through CSS
     <https://developer.gnome.org/gtk3/stable/chap-css-overview.html>
     instead, e.g. via

      .imageview.transparent {
          background-image: url('checkers.svg');
      }

    *
     "set_interpolation()" now accepts "cairo_filter_t"
     <https://www.cairographics.org/manual/cairo-cairo-pattern-t.html#cairo-
     filter-t> instead of "GdkInterpType"
     <https://developer.gnome.org/gdk-pixbuf/stable/gdk-pixbuf-Scaling.html#
     GdkInterpType>.

BUGS AND LIMITATIONS
    This should be rewritten on C, and Perl bindings should be provided via
    Glib Object Introspection.

AUTHOR
    Jeffrey Ratcliffe, <jffry@posteo.net>

    Alexey Sokolov <sokolov@google.com>

LICENSE AND COPYRIGHT
    Copyright (C) 2018--2020 by Jeffrey Ratcliffe

    Copyright (C) 2020 by Google LLC

    Modelled after the GtkImageView C widget by Björn Lindqvist
    <bjourne@gmail.com>

    This library is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself, either Perl version 5.8.5 or, at
    your option, any later version of Perl 5 you may have available.