Python以相对于整数的颜色创建图像

Question

I need to make an image, in Python, that looks like this but vertical and only green to red: http://www.google.co.uk/imgres?safe=off&espv=2&es_sm=91&biw=1280&bih=610&tbm=isch&tbnid=AuJytAtra5ARrM%3A&imgrefurl=http%3A%2F%2Fsvs.gsfc.nasa.gov%2Fgoto%3F4050&docid=cJwEIWqHngeBPM&imgurl=http%3A%2F%2Fsvs.gsfc.nasa.gov%2Fvis%2Fa000000%2Fa004000%2Fa004050%2Fcbar_scientists.png&w=1046&h=221&ei=9WMsU_TkHM-0hAfwyoDQBQ&zoom=1&ved=0CF4QhBwwAw&iact=rc&dur=194&page=1&start=0&ndsp=15

where green is 10 and red is 0. When it receives a number, it makes the bar colour up to the relevant point and b&w from there up. I then need Python to save this image to a location.

In this way, the image will represent how far away some thing is and show it in colour (green is far away - safe, red is close - danger) on the bar.

I know it's difficult to understand but how would I go about this?

Thanks!

Answer 1

I know nothing at all about Python, but I know a little about ImageMagick which is available here and has Python bindings.

If you run this ImageMagick command at the command line:

convert -size 100x500 gradient:#00ff00-#ff0000 full.jpg

you will get a 100x500 pixel image, called full.jpg , with a gradient from green to red that looks like this:

If you then run the following command:

convert full.jpg -gravity North -background gray -crop 100x250+0+0! -extent 100x500 crop.jpg

you will get a new image, called crop.jpg , that looks like this:

The 250 is the number that will control the amount that gets greyed out, so try varying that. So if your input number you mentioned is 1 , maybe you would use 50 in place of 250 (because 1/10th of the 500px image height is 50px), if it is 2 maybe use 100 in place of 250 ...

And maybe that will help - maybe it won't!!!