Drawing diagonal lines on an image

Question

Hi im trying to draw diagonal lines across an image top right to bottom left here is my code so far.

  width = getWidth(picture)
  height = getHeight(picture)
           


        

Answer 1

Where does your picture object comes from? What is it? What is not working so far? And what library for image access are you trying to use? (I mean, where do you get, or intend to get "getWidth, getHeight, getPixel, setColor) from?

I think no library that gives you a "pixel" as a whole object which can be used in a setColor call exists, and if it does, it would be the slowest thing in the World - maybe in the galaxy.

On the other hand, if these methods did exist and your Picture, the code above would cover all the image in black - you are getting all possible "y" values (from 0 to height) inside all possible x values (from 0 to width) of the image, and coloring each Black.

Drawing a line would require you to change x, and y at the same time, more like:

(using another "imaginary library", but one more plausible:

for x, y in zip(range(0, width), range(0, height)):
   picture.setPixel((x,y), Black) )

This would sort of work, but the line would not be perfect unless the image was perfectly square - else it would skip pixels in the widest direction of the image. To solve that a more refined algorithm is needed - but that is second to you have a real way to access pixels on an image - like using Python's Imaging Library (PIL or Pillow), or pygame, or some other library.