Thumbnail views of a JPEG image, shown actual size
The Witzend Thumbnail Image Viewer™
ActiveX control accurately displays miniature thumbnail renderings
of graphics files. Thumbnail views are adjustable to any dimension, from
postage-stamp size to full-screen.
The Witzend Thumbnail Image Viewer gives your
applications the ability to accurately render graphics images in a window of
any size, faithfully reflecting how the image would appear when shown at its
normal size. Your application simply provides a path to the graphics file,
and the Thumbnail Image Viewer does the rest. The Thumbnail Image Viewer
recognizes and displays all of these common image formats:
JPEG, GIF, TIFF,
BMP (bitmap), ICO (icon), CUR (cursor), WMF (Windows metafile), and EMF (enhanced metafile).
Files can be located virtually anywhere — a local hard drive,
a network server, or on the World Wide Web.
The screen shot at the top of this page conveys better than
anything we can say here what the Thumbnail Image Viewer is all about. It gives your
application “the whole picture”, able to convey instantly a quick idea of what a
graphics file looks like with maximum convenience for your users.
You can take the Thumbnail Image Viewer for a test drive using
our free image viewer utilities. Try them both!
WitzImg The WitzImg demonstration program lets you browse for
graphics files, and then displays a thumbnail image of each selected file. Click here to
download the utility’s installation program, named Setup3:
The Setup3 program installs the Thumbnail Image Viewer on your
system and runs the WitzImg viewer utility. The Setup package includes an
Uninstall feature. We hope you will find the WitzImg utility so handy you will
want to keep it, but otherwise you can completely restore your system to its former
configuration. Uninstall the WitzImg package either through the Add/Remove Programs applet
in Control Panel, or by running the uninstaller program directly.
SlideShow
The SlideShow utility demonstrates how an application can use the Thumbnail Image Viewer
to display multiple image files as a slideshow. Simply browse to a folder that contains
graphics files and SlideShow shows them as a series of thumbnail views. SlideShow is an
elegant program, yet its first version was written in less than an hour! (That’s the
beauty of component software.) The program is coded in Visual Basic, and is one of the
example projects that come with the Thumbnail Image Viewer.
Note: You must first execute the Setup3 program described
above before running SlideShow. This is because Setup3 installs the Thumbnail Image Viewer
ActiveX control, which SlideShow uses to display slides.
Written entirely in C++, the Witzend Thumbnail Image Viewer is an ActiveX
control only 240K in size. As is proper for component software, the
Thumbnail Image Viewer runs without the need for auxiliary library files such as
Microsoft Foundation Library (MFC) or Active Template Library (ATL). This
independence ensures fast load times. It also makes installation bullet-proof,
an important consideration when distributing the Thumbnail Image Viewer with
your applications.
Properties
Designed for simplicity, the control exposes only fourteen properties
that govern how an image appears in its view window. For example, the
Fit property determines which of three sizing options the Viewer
uses when rendering an image:
Auto-fit—The
image appears in its entirety, squeezed into the confines of the view window. The view
window can be any size determined by the client program.
Actual size—The
image appears in its full dimensions and is not sized to fit inside the view window.
Images smaller than the window appear completely, either centered in the window or at the
upper right corner.
Maintain aspect—This option is much like auto-fit, except that the Thumbnail Image Viewer
considers the image’s aspect ratio when sizing, ensuring that round circles appear
round and square boxes appear square in the thumbnail view.
Other properties include Center, which governs whether an
image is centered inside the view window. The Frame property causes the Thumbnail
Viewer to enclose the image in an attractive frame. The Logo property lets your
application specify an image to display in lieu of a selected file. This graphic can be a
company logo, a message, decoration, or any other design you wish.
Methods
Four methods, Refresh, Erase, Rotate, and Close
give the host program additional control over the display. Their names indicate what the
methods do. Rotate can turn an image to any angle from 0 to 359 degrees, but the
option is available only under Windows NT and higher. Calling Rotate under Windows
95 or 98 does no harm, but the method ignores the call.
A note about file locations—The Witzend
Thumbnail Image Viewer can read image files from disk or off the Web. The client
application simply provides a file path or URL address specifying a location, and the
Thumbnail Image Viewer automatically retrieves, parses, and displays the file.
Drag-and-drop
The Thumbnail Image Viewer component provides extensive support for
drag-and-drop, recognizing dropped content from various sources:
Files—An image file can be dragged
from any Windows Explorer source. The Thumbnail Image Viewer takes care
of all the details of locating and rendering the image.
HTML—The Thumbnail Image Viewer
recognizes drops from any HTML source. For instance, the user can drag
an image from a browser window and drop it onto the Viewer, where it can
be rotated and resized.
Text—Text drops, which might be a
file path or URL, can be from any text source that supports
drag-and-drop, such as a word processor.
The Thumbnail Image Viewer fires COM events to keep the container
application informed of drop activity as it occurs. Your application can
optionally receive notifications when a drag is detected, when a drop occurs,
and when the cursor leaves the Viewer window.
Color mode
The Thumbnail Image Viewer recognizes 256-color mode, and
intelligently manages palettes as required when displaying images. The host program can
even specify its own palette.
Threading
The Thumbnail Image Viewer uses apartment threading,
making access very efficient for multi-threaded applications.
The Thumbnail Image Viewer ActiveX control costs only $49.95 US
for a royalty-free license. The product comes with a 30-day warranty, and includes
complete on-line documentation and source code demonstrating how to use the Thumbnail
Viewer in a typical C++, Visual Basic, or Web-based project.
