ePanorama.net - General

Publishing circuit diagrams on web

Written by Tomi Engdahl 1999,2000

Possible file formats

Native file format of the CAD program

The native format of the circuit drawing tools is very convient for all of those who have similat circuit drawing program that you have. The circuit diagram can be easily loaded to the CAD program for printing and modifying.

For other users this format is and is not convient usually useless. Even if your CAD program some freeware/shareware program which is easily available or there is a free viewer available for the CAD program you use, this is not very convient. Quite few people want to to install some new program for their computer just to view few files (propably there is not even a viewer which works in their system). Usually around 90% of users are do not want or can't install some special viewers for their computer.

This native format is not convient for web publishing, because if you are using it, around 90% of possible viewers will not see it. So it is a good idea to provide the circuit diagram on web page in some other format which is more easily viewable. The native format file can be an additional extra on page, but it should not be the only format in which the circuit diagram is available.

GIF picture

GIF picture format is the basic picture format supported by all wildely used graphical web browser program. GIF format is the most widely used format for putting small circuit diagram to the web page. It provides very good results and small file size (fast downloading). The downside of the GIF format is that is is not convient for large circuit diagrams because of the low resolution of normal web display and problems in viewing big GIF pictures with web browsers (large picture needs very much memory on computer viewing it).

If you have a small and simple circuit to put to a web page, put it to GIF format on your web page.


JPEG is another widely used picture format in web system. It is optimized for photographic color pictures, which means that it does not perform that well with pictures like circuit diagrams, which usually are black and white or have very few colors. If you use JPEG file instead of GIF file you usually end up having worse results than with GIF pictures. If you want the same picure quality than with GIF file, you wil end up having much bigger file size than with GIF. If you make the JPEG file size to be very small (lots of compression), you will see tha artifacts of the JPEG lossy compression scheme clearly on the picture (typically "dirty copy" look on black and white pictures).

Other bitmap picture formats

There is no good reason to use other bitmap formats for circuit diagrams on the web, because GIF perform in this kind of application better than almost all other widely used graphics formats and is widely supported. If you put the pictures to BMP, PCX or TIFF format you will end up having a larger file size and most of the users can't easily see the picture.

Postsctipt format

Postscript format is quite usable format, because it allows good resolution on drawing. The postscript files can be downloaded and copied to a printer for high quality printouts. Postscript-files can be viewer in computer pscreen by using Ghostscript.

You can generate postscript files by installing a Postscript printer driver (the printer type does not matter much) to your computer and print from your program through that driver to a file. One suitable place to download a postscript driver which makes quite goor postscript is http://www.adobe.com/support/downloads/pdrvwin.htm.

Adobe Acrobat format

Adobe Acrobat is a file format from Adobe to distribute high quality document in electronic format. Adobe Acrobat files can be easily viewed on computer screen and printed using free Adobe Acrobat viewer. Adobe Acrobat format is quite videly used for distributing technical documents (application notes, component data sheets, white papers, circuit diagrams) on the web, so most of the users looking for information in electronics field has this viewer already installed in their computer.

To make Adobe Acrobat (PDF) files propably the easiest way is to buy the Adobe Acrobat Distiller program package from Adobe and use it. That program can be used to print quite directly to Adobe Acrobat format or for conberting Postscript (and many other file formats) to Adobe Acrobat document format.

Drawing Web Format (DWF)

If your CAD program export file to DXF, Autodesk (Autocad) has a utility to convert DXF to DWF. WHIP is a plugin from Autodesk for MS IE or Netscape for viewing Drawing Web Format (DWF) files.

The problem of this method is that the Plug-in is only available for limited selection of computer environments and web brosers and you have to also install this plug-in to your computer. DWF is an industry Internet standard recognized by the IETF. Developed by Autodesk as an open file format for the transfer of drawings over networks, including the Internet, so the suppot of this system might increase in the future.

Methods for converting the circuit diagram to a GIF or JPEG file

Screen capturing

Picture capturing in Windows: After you get the schematic on the screen the way you like, hit the "print screen" key to copy it to the clipboard. A number of programs will let you paste this snapshot then save as a gif or jpg. Image manipulation programs are where I would look first (Corel PhotoPaint, Paintshop Pro,etc.) or try opening a blank image using most image capture programs that come with scanners, then paste. You then crop out the parts you don't want and save in the desired format. Even newer word processors can save in html format, converting the graphics to .jpg in the process. You probably have at least one program that already does the job.

You can also use a nice little program called "Printscreen" . after I have set the size of the schematic to be copied I use Printscreen to copy and save it into a format of your choice black/colour graphic and save it anywhere you want for further use.

File format conversion

If your CAD software can produce a HPGL plotter file, a shareware utility called PrintGL does a great job of converting the HPGL to a bitmap PCX format. After conversion your letters look like a plotter drew them. You can then import this picture to any drawing program and save the file in GIF format.

How to make a Postscript file

Many circuit diagram packages have an option to print to a Postscript printer. You can make a Postscript file just by making a program to print to a postscript printer (select a standard postscript if that type of printer is available) and redirect the results to a file. If you use a Windows based CAD program you just need to install a Postscript driver for Windows and make it to output to a file.

How to make an Adobe Acrobat file

Adobe Acrobat file format is designed by Adobe and they have commercial Adobe Acrobat Distiller package for making Adobe Acrobat files. Typically you first convert the circuit diagram to Postscript and then use distiller to make an Adobe Acrobat (PDF) file.

If you search the web for Ghostscript and Gsview they can turn postscript into .pdf files for free. Just install a postscript printer driver and use it from the circuit drawing tool you have.

author: Tomi Engdahl