Thumbnail

Status: Version 1.3.0-2 has been released on March 10th 2013
Changes:
- v1.3.0-2: Updated libThumbnail to use the Media:Width and Media:Height attributes used by Haiku (for the source, and both En and De versions). Added an HVIF icon for Haiku. Updated documentation to html5 and using recent images from Haiku.
- v1.3.0: Localization: at the moment there exist English and German versions. Translators for other languages are very welcome.
- v1.2.1: Bug fix in Thumbnail: could crash after processing lots of images. Bug fix in libThumbnail: used to crash for extreme aspects. Now much smarter in shrinking images with extreme aspects: instead of creating a thin line it shrinks a clipped part from the center of the image.
- v1.2.0: Can now add resolution attributes to the image subtypes of the MIME database, so that the resolution attributes which are created for image files can be viewed with the Tracker (see Preferences). Some bug fixes connected with the add-on. Small change to the shared library.
- v1.1.0: Scripting. No command line modus anymore (use scripting for that). Slightly changed UI. Now uses the Translation Kit instead of Datatypes. Small change to the shared library.
License: Version 1.3.0 is Freeware, the source code/libThumbnail.so may be used freely
Copyright 1997, 1998 by Thorsten Seitz
Requirements: libprefs.so, BeOS R3.1

Introduction

Thumbnail is an application which creates thumbnails for image files. By default it overwrites the mini icon and the icon which are displayed in Tracker windows and creates an additional attribute for the image file which contains a larger thumbnail (with a maximum side length of 96 pixels) which may be used by other applications. Furthermore it creates two integer attributes containing the width and height of the original image. See here for a detailed description which attributes are created.

The original image is left untouched, of course.

A preference panel allows you to select which attributes are actually written.

Thumbnail is accompanied by a Tracker add-on named MakeThumbnail which simply launches Thumbnail and sends the current selection to it.

The following image shows a Tracker window after Thumbnail has overwritten the icons of the image files:

Requirements

Thumbnail uses the Translation Kit which is built into the BeOS. It can create thumbnails only for image files whose format can be translated by the handlers you have installed in the home/config/add-ons/Translators folder.

Furthermore Thumbnail requires libprefs.so from Jon Watte to save its preferences. This shared library must be installed in the home/config/lib folder or anywhere else the BeOS can find it. (The Thumbnail distribution contains libprefs.so from the version 1.2.5 of the libprefs package.)

(Thumbnail requires a shared library named libThumbnail.so which comes with the Thumbnail distribution and must be installed in the home/config/lib folder or anywhere else the BeOS can find it.

This shared library may be used from other programs. See below for further informations.)

Creating Thumbnails

by launching Thumbnail:
You can then drop files and/or folders on its window to create thumbnails for all dropped image files which can be translated. Dropped folders are searched recursively.
by using the Tracker add-on MakeThumbnails:
The add-on MakeThumbnails should have been copied into the home/config/add-ons/Tracker folder by the installer. If not you can double-click it to open a dialog which lets you have it moved automatically to the correct folder.

After each image of a selection has been processed, the created icons and the created thumbnail are displayed. Pressing the Stop button interrupts the processing of the following images. The About menu item opens a window with information about the application.

This is the Thumbnail window after dropping the image file 0670.jpg on it.

Preferences

Thumbnail preferences window

The preference window can be accessed by selecting the Preferences menu item in the Thumbnail window.

On the "Thumbnail Creation" tab you can mark if alerts telling that the format of a specific file has not been understood shall be suppressed, if icons or the large thumbnail shall be shown and/or written into attributes (written icons/thumbnails are always shown), if the large thumbnail shall be dithered to the 8 Bit color palette instead of being created as true color image and if the resolution of the original image shall be written into a width and height attribute.

On the "MIME Database" tab you can mark if the MIME database shall be updated each time Thumbnail is launched. This updating adds a width and a height attribute to each subtype of image if not already present. This makes it possible to view the width and height attributes of image files with the Tracker.

Description of the buttons:

Revert: display prefs which are currently used.
Reload: display saved prefs.
Defaults: display default values.
Use: use displayed prefs (without saving them to disk).
Save: save displayed prefs and use them.

Closing the preferences window doesn't change anything.

Scripting

You can use 'hey' which has been written by Attila Mezei (or anything else that sends scripting messages) to script Thumbnail.

Creating Thumbnails:

To create thumbnails, send a standard B_REFS_RECEIVED message. This is not a real scripting message, but can be sent by "hey": hey Thumbnail load "file(full-path-to-file)"

Changing Preferences:

Thumbnail has a property named "Preferences" which in turn has a property named "Thumbnail Creation" (this is the grouping tab in the preferences window). This property serves as a root group for preferences and understands the suite named "suite/vnd.dragonfly-pref-group" in addition to the standard suite "suite/vnd.Be-handler". The root group contains preferences or preference groups. A preference understands the suite named "suite/vnd.dragonfly-pref" in addition to the standard suite "suite/vnd.Be-handler", whereas a preference group just understands the standard suite "suite/vnd.Be-handler".

Description of the suites:

suite/vnd.dragonfly-pref-root

Property name: label of the tab, i.e. "Thumbnail Creation"
Specifiers: B_DIRECT_SPECIFIER only
Messages: '*REV', '*REL', '*DEF', '*USE', '*SAV' with the same functions as the appropriate buttons (see last section).
Data type: none

suite/vnd.dragonfly-pref

Property name: label of the preference, e.g. "Suppress Alerts" or "Show"
Specifiers: B_DIRECT_SPECIFIER only
Messages: B_GET_PROPERTY, B_SET_PROPERTY, '*USE' for getting the value in use, setting the displayed value and using the displayed value.
Data type: bool

Examples:

Note the '*USE' command. Without this, the new values won't be used!


		hey Thumbnail get "Suppress Alerts" of "Thumbnail Creation" of Preferences

		hey Thumbnail set "Suppress Alerts" of "Thumbnail Creation" of Preferences to true

		hey Thumbnail set "Write" of "Mini Icon" of "Thumbnail Creation" of Preferences to false

		hey Thumbnail '*USE' "Thumbnail Creation" of Preferences

		hey Thumbnail load "file(/boot/optional/images/Fearless Leader)"

Attributes format

The format of the attributes which are created by Thumbnail is the following:

Mini Icon

This is the standard mini icon displayed by the tracker.

Name: BEOS:M:STD_ICON
Type: 'MICN'

Large Icon

This is the standard large icon displayed by the tracker.

Name: BEOS:L:STD_ICON
Type: 'ICON'

Thumbnail

The longest side of the thumbnail is 96 pixels long (or smaller if the original image has been smaller). The other side is scaled with the aspect of the original image. The thumbnail is a BBitmap which has been archived into a BMessage which has been flattened and then been written into the attribute. The color space of the BBitmap is either B_COLOR_8_BIT (if dithering was checked) or B_RGB_32_BIT.

Name: GRAFX:Thumbnail
Type: B_MESSAGE_TYPE ('MSGG')
Format: Flattened BMessage. The unflattened BMessage is a BBitmap archive.

Width

Name: GRAFX:Width
Type: B_INT32_TYPE ('LONG')
Format: int32

Height

Name: GRAFX:Height
Type: B_INT32_TYPE ('LONG')
Format: int32

Source Code and shared library

A shared library named libThumbnail.so is included, as well as the source code to create this library. The library is used by the application Thumbnail and may be used freely by your programs. Simply include the header file Thumbnail.h which declares a class named DThumbnail and link with libThumbnail.so. The class DThumbnail lets you easily create thumbnails from BBitmaps and read/write them from/into file attributes. The following example shows its usage:


// bitmap is assumed to be a BBitmap-pointer of an image
// for which you want to create a thumbnail
// view is assumed to be a BView where you want to display
// the thumbnail
// ref is assumed to be an entry_ref to the file where the image
// comes from

bool dither = true;         // the thumbnail will be dithered
DThumbnail thumbnail(bitmap, dither);

if (thumbnail->Bitmap())    // will be NULL if the thumbnail couldn't be created
{
    view->DrawBitmap(thumbnail->Bitmap());

    BNode node(&ref);
    thumbnail->WriteThumbnailAttribute(&node);
    thumbnail->WriteIconAttribute(&node);
    thumbnail->WriteMiniIconAttribute(&node);
    thumbnail->WriteResolutionAttributes(&node);
}

NOTE: There has been a change to the library: the type of DThumbnail::cThumbnailSize has been changed from int32 to enum. This has been necessary due to a bug in the exporting mechanism.