# Glimmr Canvas-Based Drawing

## version 2/101030 by Erik Temple

Section - Centering algorithm for image-maps

To decide what list of numbers is the center-point of (grid - an image-map):
let dx be a number;
let dy be a number;
let x be entry 1 of the origin of grid;
let y be entry 2 of the origin of grid;
let imap-x be the desired tile-width of the grid;
let imap-y be the desired tile-height of the grid;
if the asymmetrical scaling option is not active:
let dx be imap-x real times the the scaling factor of the grid as an integer;
let dy be imap-y real times the scaling factor of the grid as an integer;
otherwise:
let dx be imap-x real times the x-scaling factor of the grid as an integer;
let dy be imap-y real times the y-scaling factor of the grid as an integer;
let the calc-height be the number of entries of the tile-array of the grid;
let the calc-width be the number of entries in entry 1 of the tile-array of the grid;
let dx be dx * calc-width;
let dy be dy * calc-height;
let x be x + (dx / 2);
let y be y + (dy / 2);
let coord be {0, 0};
now entry 1 of coord is x;
now entry 2 of coord is y;
decide on coord.