Drawing a chessboard v2.1

This version of my series Drawing a chessboard is a minor update of the version 2.0 and is only different because it contains one loop to scan the image.


In this version, I create an 8x8 image with a black background and assign the white color by scanning this image in ONE loop. Indeed, there is 64 cells in the chessboard and they can be numbered from 0 (the top left cell) to 63 (the bottom right). The question is now: How can we extract the XY-coordinates from these indexes?
In the following figure, on the left, the chessboard contains the cell indexes. For example, the cell # 13 has XY-coordinates (5,1).

Now, the formula to calculate the cell index from the XY-coordinates is given above and corresponds to the Y-coordinate multiplied by the image width plus the X-coordinate.Ex: 13 = 1 * 8 + 5
And to extract the coordinates,
- X is calculated from the remainder after division by the image width.
- Y is the result of the integer division of the cell index by the image width.

Here is the final code...
+++ IJ snippet: chessboard_v2_1_imagej.ijm +++

	//
	// chessboard version 2.1
	// using one loop
	// Jean-Christophe Taveau
	//
	chessSize=512;
	newImage("chess", "8-bit Black", 8, 8, 1);
	for (i=0;i<8*8;i++)
	{
	x=i%8;
	y=floor(i/8);
	if ((x+y)%2==0) {
	setPixel(x,y,255);
	}
	}
	// Scale the 8x8 image to build the final chessboard
	run("Size...", "width="+chessSize+" height="+chessSize+" constrain average interpolation=None");

view raw gistfile1.js hosted with ❤ by GitHub

+++ End of IJ snippet +++