补齐下述Bresenham算法。
if(delatRow < 0) stepRow = -1;else stepRow = 1;

if(delatCol < 0) stepCol = -1;else stepCol = 1;

delatRow = abs(delatRow *2);

delatCol = abs(delatCol *2);

currentStep = 0;

pathRow [currentStep] = nextRow;

pathCol [currentStep] = nextCol;

currentStep ++ ;

。。。

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