A utility which accepts a string via HTTP endpoint, and returns a PNG graphic of that text.
txt2png lets you generate obfuscated base64-encoded inline PNG images. This is useful in cases like these:
- Include an email address in a web page, while hiding it from (low-effort) scrapers:
- Embed politically sensitive text which is only rendered at page load time:
- Dynamically generate an image from a URI query string.
You can experiment with this tool at https://txt2png.3dbrows.dev. Please don't use this hosted service for anything but trying out the tool; it's not for any production workloads. For that, host it yourself.
A Docker image is available on DockerHub at 3dbrows/txt2png. Example use:
docker run -p "8080:80" -e Input__MaxLength=80 -e Logging__LogLevel__Microsoft=None 3dbrows/txt2png
The optional flag -e Input__MaxLength=80 (N.B. two underscores) sets the max input length to 80 chars instead of the default 280. The optional flag -e Logging__LogLevel__Microsoft=None turns off logging (also two underscores), so you can avoid keeping logs of user requests if you wish. ("What you don't log can't be subpoenaed.")
Access the test harness in your browser at http://localhost:8080 or make command-line requests like so:
curl -i -H "Accept: text/plain" http://localhost:8080/Txt2Png/v1?input=foo%40example.com
In the test harness, use the "Try it out" function and toggle between image/png and text/plain to obtain the PNG image or the Base64 encoding thereof.
An OpenAPI v3 specification is available at /swagger/v1.0/swagger.json.
Here is how to generate this image:
$ curl -i -H "Accept: text/plain" http://localhost:8080/Txt2Png/v1?input=foo%40example.com&background=white
Use the returned Base64 string in HTML like this:
<img alt="Image generated by github.com/3dbrows/txt2png" src="data:image/png;base64,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" />Or, use it in Markdown like this:
$ curl -i http://localhost:8080/Txt2Png/v1?input=foo%40example.com&background=white
(If you want, you can optionally specify a header of Accept: image/png.)
Use it in HTML like this:
<img alt="Image generated by github.com/3dbrows/txt2png" src="http://localhost:8080/Txt2Png/v1?input=foo%40example.com&background=white" />Or, use it in Markdown like this:
In this example, the input text is within your page source, which offers no privacy at all; so don't use this method if you are trying to conceal anything from scrapers.
- Please URI-encode the input.
- Consider accessibility concerns e.g. how will a blind person's screen reader react to the image? Use meaningful alt-text in the
imgtag. - Be advised that any attempts to obtain security or privacy through obscurity are ineffective against any sufficiently determined attacker. This tool merely raises the threshold of effort required to harvest mildly sensitive data (such as email addresses). Please do not confuse this tool for any form of cryptography.
- Please note that GitHub does not support the display of embedded Base64 images in Markdown (using
data:image/png;base64,...). - Style options are black text on a white or transparent background, or white text on a black background. This allows a monochromatic (hence smaller) image.
Please see LICENSE and CONTRIBUTING.md.
Donations welcome:
