private float getCenterXForColumn(int column) {
        return paddingLeft + column * squareWidth + squareWidth / 2f;
    }
Helper method to find the column x fallis into.

@param x The x coordinate.
@return The column that x falls in, or -1 if it falls in no column.
android-patternview/src/main/java/com/eftimoff/patternview/PatternView.java