Feature Request: allow changing line colors in area measurements

[achavarriae]

Your area measurements feature is great, but would it be possible to change the color of the guide line between the points? Right now i`m working with images with black background and it is very difficult to follow the guide line between the points.

Thanks for your consideration.

Best,

Ana

[nbehrnd]

A quick solution for now may be to work on the image to be processed in first place; namely: inversion of the colours, replacement of (what appears to be) a black background by a white one. Then resubmit the prepared image to WebPlotDigitizer again.

See if you may install ImageMagick on your computer. It is a set of useful programs for all kind of image processing, freely available for Windows, Mac, or Linux. On the terminal, enter the directory where your image resides, than issue a command in the pattern of

convert input.png -negate -modulate 100,100,0 output.png

where input.png obviously is place holder for the file to be processed, and output.png the name of the result (you may choose this one freely) to generate an illustration like the following:

I credit Jimmy Kromann for hinting this useful command.

Then however I equally suggest to test 1) to trace the complete curve (e.g., the turquoise one) with the digitizer's colour picker, and 2) to submit the (x,y)-data to the freely available fityk. Initially developed for X-ray crystallography, it contains multiple algorithms to model peak shapes equally seen in other sciences (e.g., chromatography, spectroscopy), offers background subtraction, and peak area integration (example). If recurrent, its use may be scripted, too.