Function crossesViewport

src/traces/scatter/line_points.js:89–100

(xFrac0, yFrac0, xFrac1, yFrac1)

    }

    function crossesViewport(xFrac0, yFrac0, xFrac1, yFrac1) {
        var dx = xFrac1 - xFrac0;
        var dy = yFrac1 - yFrac0;
        var dx0 = 0.5 - xFrac0;
        var dy0 = 0.5 - yFrac0;
        var norm2 = dx * dx + dy * dy;
        var dot = dx * dx0 + dy * dy0;
        if(dot > 0 && dot < norm2) {
            var cross = dx0 * dy - dy0 * dx;
            if(cross * cross < norm2) return true;
        }
    }

    var latestXFrac, latestYFrac;
    // if we're off-screen, increase tolerance over baseTolerance