Tk-JThumbnail version 0.01
==========================

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example C compilers and installed libraries) and any other information
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INSTALLATION

To install this module type the following:

   perl Makefile.PL
   make
   make test
   make install

DEPENDENCIES
    Perl 5, Tk Tk::LabEntry Tk::JPEG Tk::PNG File::Basename

    Optional: Tk::Animation (for GIF animation)

NAME
    Tk::JThumbnail - Present a list of files in a directory as a grid of
    icons with or without text.

AUTHOR
    Jim Turner

    (c) 2019, Jim Turner under the same license that Perl 5 itself is. All
    rights reserved.

ACKNOWLEDGEMENTS
    Derived from Tk::Thumbnail, by Stephen O. Lidie (Copyright (C) 2001 -
    2005, Steve Lidie. All rights reserved.)

LICENSE AND COPYRIGHT
    Copyright (c) 2019 Jim Turner.

    Tk::JThumbnail is free software; you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published
    by the Free Software Foundation; either version 2.1 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful, but
    WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
    General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with this program; if not, write to the Free Software Foundation,
    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

SYNOPSIS
            my $thumb = $parent->JThumbnail(-option => value, ... );

EXAMPLE
            #!/usr/bin/perl -w

            use strict;
            use Tk;
            use Tk::JThumbnail;

            my $mw = MainWindow->new;
            my @list = directory($ARGV[0] || '.');  #Directory to fetch files from.

            my $thumb = $mw->Scrolled('JThumbnail',
                            -images => \@list,
                            -width => 500,
                            -scrollbars => 'osoe',
                            -highlightthickness => 1,
                            -focus => 2,
                            -nodirs => 1,
            )->pack(-side => 'top', -expand => 1, -fill => 'both');

            $thumb->Subwidget('yscrollbar')->configure(-takefocus => 0);
            $thumb->Subwidget('xscrollbar')->configure(-takefocus => 0);
            $thumb->Subwidget('corner')->Button(
                            -bitmap => $Tk::JThumbnail::CORNER,
                            -borderwidth => 1,
                            -takefocus => 0,
                            -command => [\&cornerjump, $thumb],
            )->pack;

            my $b2 = $mw->Button(
                            -text=>'E~xit',
                            -command => sub{
                                            print "ok, bye.\n";
                                            exit(0)
                            }
            )->pack(qw/-side top/);

            #EXAMPLE CALLBACK BINDING (RIGHT MOUSE-BUTTON):
            $thumb->bindImages('<ButtonRelease-3>' => [\&RighClickFunction]);

            $thumb->focus();

            MainLoop;

            exit(0);

            sub RighClickFunction  #CALLBACK BOUND TO RIGHT MOUSE-BUTTON:
            {
                    my $self = pop;

                    my $indx = $self->index('mouse');
                    my $fn = $self->get($indx);
                    print "---You right-clicked on file ($fn) at position: $indx!\n";
            }

            sub cornerjump   #CALLBACK WHEN "CORNER" BUTTON PRESSED:
            {
                    my $self = shift;

                    $self->activate($self->index('active') ? 0 : 'end');
            }

            sub directory   #FETCH LIST OF IMAGE FILES TO BE DISPLAYED:
            {
                    my ($dir) = @_;
                    chdir($dir);
                    $dir .= '/'  unless ($dir =~ m#\/#);
                    my $pwd = `pwd`; chomp $pwd;
                    $mw->title ("Directory: $pwd");
                    opendir (DIR, ".") or die "Cannot open '.': $!\n";
                    my @files = ();
                    foreach my $name (readdir(DIR)) {       
                            my $st = stat($name);
                            next  unless ($st);
                            push @files, $name;
                    }
                    return sort @files;
            }

DESCRIPTION
    Tk::JThumbnail is derived from the old Tk::Thumbnail widget. The reason
    for this fork is to:

    1) Fix some issues including an FTBFS to run in modern Perl 5.

    2) Add some features needed to use in my JFM5 Filemanager to provide it
    with a "graphical" option of displaying files in a directory with
    thumbnail images (including icons based on file extension), along with
    the other ("text") option uses my Tk::HMListbox widget, similarly
    derived from the older Tk::MListbox. (JFM5 is derived from my JFM4
    filemanager, but adds an icon-view using THIS module)!

    The main new features are:

    1) Ability to display an alternate icon for non-image files, based on
    their file-extension.

    2) Ability to "select" images (files) for further processing (as is done
    in a file-manager).

    3) Ability to bind both mouse and keyboard operatons to the individual
    images allowing for right-clicking, shift-clicking, dragging to select /
    unselect images, keyboard-traversal via arrow-keys, etc.

    4) Added method compatability with Tk::HMListbox methods needed by a
    filemanager (JFM5 in particular) to allow for both to be swapped in and
    out with very similar code, while minimizing changes needed for giving
    the file-manager user the ability to display files either in line-detail
    mode (Tk::HMListbox) or icon-mode (Tk::JThumbnail) and interact on them
    in a similar fashon.

    5) A "default" (fail-through) image added for display when a non-image
    file is encountered or an image file that can not be properly rendered.
    This file is in images/ and is called "failimg.png", and can be replaced
    with whatever default image you wish to use (must be named
    "failimg.png").

    6) Perl can CRASH (segfault) if a .xpm image containing the C comment
    string "/*" is processed - OUCH! We work around this now by reading in
    .xpm images and converting this string to something harmless.

    The original relevant Tk::Thumbnail documentation, including our
    additions follows below:

    Create a table of thumbnail images, having a default size of 32 x 32
    pixels. Once we have a Photo of an image, shrink it by copying a
    subsample of the original to a blank Photo. Images smaller than the
    thumbnail dimensions are enlarged by zooiming.

    Clicking on an image displays it full-size in a separate window with a
    "Get Info" button. The info window shows the image's width, height, path
    name, size and frame count.

    For multi-frame GIFs the image is shown with an extra button to play /
    stop the animation.

    -blank
        For animated GIFs, a boolean specifying whether to blank the
        animation photo between movie frames. Default is now *0* (*FALSE*).
        This flag is passed to Tk::Animation's *set_disposal_method*().

    -columns
        Number of Photos per row. The column count is computed if not
        specified. Default: computed to mostly form a square (columns ==
        rows).

    -command
        A Legacy callback that's executed on a <Button-1> event over a
        thumbnail image. It's passed 2 arguments: the thumbnail widget
        itself, and the index of the image clicked on (or the active image
        if <Return> key pressed. In Tk::Thumbnail It was passed six
        arguments: the Label widget reference containing the thumbnail Photo
        image, the file name of the Photo, a boolean indicating whether or
        not the the Photo is valid, the Photo's pixel width and height, and
        a boolean indicating whether the image is a single frame (Tk::Photo)
        or has multiple frames (Tk::Animation); but now this information can
        be fetched form the hash referenced by $self->{'data'}[$index] where
        $self and $index represent the two arguments passed in.

        A default callback is provided that simply displays the original
        image in a new Toplevel widget, along with a Get Info Button that
        opens another Toplevel containing information about the image. For
        multi-frame GIFs the image is shown with an extra button to play /
        stop the animation.

        To override this default <Button-1> callback, use the *bindImages*()
        function to set your own, or set -command => undef to have no
        <Button-1> callback.

        Example: *$thumb*->bindImages('<Button-1>' => [\&*mycallbackfn* [,
        args] ]);

    -extimages
        JThumbnail-added feature: Optional reference to a hash of icon
        images to be displayed for non-image files. The hash keys are file
        extensions and the values image files for the icons. Default: {}
        (*none*).

        Example: {'txt' => '/usr/local/pixmaps/texticon.png', 'pdf' =>
        '/usr/local/pixmaps/adobe.jpg' [, ...]}

        Special keys are: '' for files with no or unrecognized extension,
        and 'dir' for directories.

    -focus
        JThumbnail-added feature: Specify the focusing model. Valid values
        are:

        0: Never take keyboard focus (and skip in the main window's
        tab-focusing order).

        1: Take focus when tabbed to from the main window (normal
        "-takefocus => 1" action for Tk widgets).

        2: Also take keyboard focus whenever an icon in the widget or the
        widget itself is clicked on.

        Default: *1*.

    -font
        The default font is fixed.

    -highlightthickness
        Set the frame border around the images, becomes visible when widget
        has keyboard focus. Default *0* (*none*). Recommended: *1* (pixel
        wide).

    -ilabels
        A boolean, set to *TRUE* if you want file names displayed under the
        thumbnail images. Default *TRUE*.

    -images
        A list (reference) of file names and/or Photo widgets. JThumbnail
        creates temporarty Photo images from all the files, and destroys
        them when the JThumbnail is destroyed or when a new list of images
        is specified in a subsequent configure call. Already existing Photos
        are left untouched.

    -iheight
        Pixel height of the thumbnails. Default is *32*. The special value
        -1 means don't shrink images in the Y direction.

    -iwidth
        Pixel width of the thumbnails. Default is *32*. The special value -1
        means don't shrink images in the X direction.

    -nodirs
        JThumbnail-added feature: Do not include directories in the list.
        Default *0* (*FALSE*) - include them.

    -noexpand
        JThumbnail-added feature: If set to *TRUE*, Do not zoom tiny images
        (smaller than *-iwidth* x *-iheight*) to fill those dimensions, but
        keep their original size. Default is *0* (*FALSE*) - zoom (expand)
        them until one dimension fills that space (aspect maintained), as
        Tk::Thumbnail does.

    -selectbackground
        JThumbnail-added feature: Set a different background color for
        images that are "selected". Default: the palette's
        "*readonlyBackground*" or "*highlightBackground*", or, if those are
        the same as the current background, a different shade of gray will
        be used.

    -selected
        JThumbnail-added feature: Optional reference to a list of boolean
        values corresponding to the indicies of images to be marked as
        currently "selected". Default: [] (*none*).

        Example: To select the first and fifth images: -selected =>
        [1,0,0,0,1]

        All images beyond the fifth will not be selected.

    -takefocus
        NOTE: DO NOT USE (it doesn't work properly)! Instead use the -focus
        option, see above:

METHODS
    $thumb->activate(*index*);
        JThumbnail-added feature: Sets the active element to the one
        indicated by *index*. If *index* is outside the range of elements in
        the list then *undef* is returned. The active element is drawn with
        a ridge around it, and its index may be retrieved with the index
        'active'.

    $thumb->bindImages(*sequence*, *callback*);
        JThumbnail-added feature: Adds the binding to all images in the
        widget. This is needed because normal events to the main widget
        itself are NOT passed down to the image subwidgets themselves.

    $thumb->bindRows(*sequence*, *callback*);
        JThumbnail-added feature: Synonym for bindImages for compatability
        in file-managers, etc. that use both this and Tk::HMListbox
        interchangability for displaying directory contents. Other that
        that, it really has nothing to do with "rows".

    $thumb->clear();
        Destroys all Frames and Labels, and deletes all the temporary Photo
        images, in preparation for re-populating the JThumbnail with new
        data.

    $thumb->curselection();
        JThumbnail-added feature: Returns a list containing the numerical
        indices of all of the elements in the HListbox that are currently
        selected. If there are no elements selected in the listbox then an
        empty list is returned.

    $thumb->get(*index*);
        JThumbnail-added feature: Returns the file-name of the image
        specified by *index*. *index* can be either a number, 'active', or
        'end'.

    $thumb->getRow(*index*)
        JThumbnail-added feature: In scalar context, returns the file-name
        of the image specified by *index*. In list context, returns an array
        with the following elements:

            [0]: Hash-reference to the detailed data-elements saved for each
            image.

            [1]: The file-name of the image.

            [2]: Directory indicator: either 'd' if image file is a
            directory, or '-' if not. This is from the first character of an
            "ls -l" list and is this way for compatability with
            Tk::HMListbox, as used by the JFM5 file-manager for determining
            whether an entry is a directory or not.

        This method is provided for convenience for creating file-managers,
        such as JFM5.

        The keys of the hash-reference (first argument) are:

            -index:  Index number of the image file returned.

            -label:  Widget containing the image.

            -filename:  File-name of the image.

            -bad:  True if not an image file or the image could not be rendered.

            -width:  The pixel width of the image file.

            -height:  The pixel height of the image file.

            -animated:  True if the image is an animation (animated GIF).

            -blankit:  The value of the boolean I<-blank> option.

            -row:  Row index# where the image is displayed in the widget.

            -col:  Column index# where the image is displayed in the widget.

            -photo:  The photo object of the image file.

    $thumb->index(*index-expression*);
        JThumbnail-added feature: Returns a valid index number based in the
        *index-expression*, or -1 if invalid or out of range.
        *index-expression* can be any of the following: *number*,
        *'active'*, *'end'*, *'mouse'*, or *'@x,y'* (where x & y are the
        pointer[x|y] pixel coordinates of the mouse cursor in the widget).
        *'mouse'* can be used to get the index of the widget under the mouse
        pointer (or just clicked on). NOTE: $thumb->index('end') returns the
        index of the last image in the list, so adding 1 to this gets the
        total count of images in the list!

    $thumb->indexOf(*image-filename*);
        JThumbnail-added feature: Returns the index# of the image file-name,
        or -1 if not a valid file-name in the list.

    $thumb->isFocused();
        JThumbnail-added feature: Returns *TRUE* if $thumb has the keyboard
        focus, *FALSE* otherwise.

    $thumb->isSelected(*index*);
        JThumbnail-added feature: Returns *TRUE* if the image is currently
        selected or *FALSE* otherwise. Returns *undef* if *index* is invalid
        or out of range. NOTE: *index* must be a valid *number*, use
        $thumb->index() to get a valid *index* number.

    $thumb->selectionSet(*index* [ , *index* ...]);
        JThumbnail-added feature: If a single *index* is given, that image
        is "selected". If two indices are given, all images between the two,
        inclusive are selected. If three or more are given, each image in
        the list is selected. *index* can be either a *number* or *end*.

    $thumb->selectionToggle(*index*);
        JThumbnail-added feature: Toggles the selection state of the image
        given by *index*, then returns the selection state of the image
        AFTER the toggle.

    $thumb->selectionClear(*index* [ , *index* ...]);
        If a single *index* is given, that image is "selected". If two
        indices are given, all images between the two, inclusive are
        de-selected, if selected. If three or more are given, each image in
        the list is de-selected. *index* can be either a *number* or *end*.

NOTES
    1) There are no insert, delete, or sort methods. One must "reconfigure"
    the widget with a new list of images in order to change the list,
    example:

    $thumb->configure(*-images* => \@filelist);

    which will replace all the images with the new list.

    2) -takefocus does not work, use -focus instead.

    3) The default for scrollbars seems to be "osow" even though I've
    specified "osoe" in this code. Not sure why, but to set "osoe"
    (SouthEast / Lower and Right), you should specify "-scrollbars =>
    'osoe'! "osoe" is best, if you are using the "corner button" option (see
    the Example in this documentation).

    4) I've replaced Tk::Thumbnail's "multimedia" buttons for animated gifs
    in the default callback which displays the image you clicked on
    full-sized in it's own window since the Tk::MultiMediaControls produces
    floods of errors about "Tk::MasterMenu" being missing, but no such
    widget seems to exist anymore?! Instead, now there's a simple Play /
    Stop button to play the animation.

    5) The default callback to display full-sized images and info. in a
    separate popup window is invoked whenever one clicks on an image OR now,
    when one presses the Return key, the active image is displayed as such.
    To NOT do this, specify:

    -command => *undef*.

    OR specify your own callback function for -command, OR override both
    *<lt*ButtonRelease-1<gt>> and *<lt*Return<gt>> key using the
    bindImages() function.

    6) There are now TWO built-in icon images included with this package:
    failimg.png and info3.png in the images/ subdirectory. You can replace
    them with whatever you wish. *failimg.png* is displayed for any
    non-image file or image file that could not be converted properly, or
    for which no -extimg image exists for it's extension. *info3.png* is
    displayed for the "info" button in the popup window image by the default
    -command callback.

    7) Tk::Animation is now an optional module (not required). Needed only
    if you wish to be able to "play" animated GIF images. NOTE: They are not
    playable from the image display screen, but only via a bound callback
    function, such as the default *-command* callback.

KEYWORDS
    jthumbnail, thumbnail, icons

SEE ALSO
    Tk::Thumbnail Tk::Photo


