At the time of this writing, spam accounts for half of all email on the internet. Countless hours are lost cleaning the spam from your inbox. One way to make better use of your time is to publish your email address while, at the same time, making it hard for spammers to harvest your address.
adr2ppm is a program package that allows you to create an image of your email address. You can publish this image on your web page and prevent spammers from harvesting your address. Surfers are able to read your email address on the web, because they can view your graphics with a conventional browser.
Since you can create an image of your email address, you can also combine that image with other graphics. With the pnmcat command, you can combine your email with a picture of your products or your business logo in the same image. With the pnmcomp command, you can place your email address on top of another picture, with transparency.
adr2ppm creates 24 bit pixels in RGB format, so you can modify the program to produce the colors you want.
adr2ppm myuserid@myisp.org
| pnmtopng >email.png
xview email.png
Second example:
adr2ppm myuserid@myisp.org | xview stdin
This example lets you view the result directly.
The Debian package netpbm contains a program pnmtopng that converts a ppm file to the png format. The resulting png file can then be included in an HTML document.
You will need to install netpbm to work with adr2ppm. If you don't have Debian, you can easily compile netpbm from source.
If you have difficulty installing netpbm, you may have an easier time compiling pngminus. pngminus will allow you to create only PNG images. See the following information about installing pngminus.
The ppm file format is the most flexible graphic file format. You can create many other types of graphic files from a ppm file. Here is a list of formatting programs available.
The following table compares other graphic formats to the PNG format. The comment shows the disadvantage of the other format compared to the PNG format. Each graphic format is evaluated for inclusion in an HTML document.
| Format | Program | Disadvantage compared to PNG |
|---|---|---|
| PNG | pnmtopng | Good license, good compression |
| GIF | ppmtogif | Restrictive license |
| JPEG | ppmtojpeg | JPEG is lossy |
| TIFF | pnmtotiff | Less compression |
| BMP | ppmtobmp | Less compression |
| PCX | ppmtopcx | Less compression |
| XPM | ppmtoxpm | XPM not for HTML |
| PS | pnmtops | PS not for HTML |