How to get the 2d coordinates(x,y) from an ordered 1d list - 0,1,2,3,4,5,6… with given width & height?

Question

the indexes of an image are stored in a 1d list with 0,1,2,3,4,5 ....(w*h) ,instead of (0,0), (0,1),(0,2)...(w,h) (given height and width of the image), How to get the indexes(x,y) from an index for example : 57?

This code only worked with squared dimensions

//width & height given
//p is the index, for eg = 57, from the ordered list - 0,1,2...57...w*h

int remainder = p %height;
int quotient = p/height;

int x = quotient;
int y = remainder;

bufferedImage.setRGB(y,x,myWhite.getRGB());

Answer 1

Your attempt is very close!

Instead of dividing by the height of the matrix, divide by the width , because the indices of the 1D array increases as you go from the left to the right of the image, then top to bottom, as opposed to top to bottom, then left to right.

int remainder = p %width;
int quotient = p/width;

int x = quotient;
int y = remainder;