Glimmr Canvas-Based Drawing

version 2/101030 by Erik Temple

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  • 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.