public bool GenerateLinear(LinearEquation linear)
{
Color lineColor = Color.Blue;//线条的颜色
Graphics g = this.CreateGraphics();
//分别获取两个端点的值，连成线即可
var x1 = this._AxisX.Max;
var y2 = this._AxisY.Max;
var x3 = 0 - this._AxisX.Max;
var y4 = 0 - this._AxisY.Max;
var y1 = linear.GetValueFromX(x1);
var x2 = linear.GetValueFromY(y2);
var y3 = linear.GetValueFromX(x3);
var x4 = linear.GetValueFromY(y4);
var point1 = new PointF(x1, y1);
var point2 = new PointF(x2, y2);
var point3 = new PointF(x3, y3);
var point4 = new PointF(x4, y4);
List <PointF> lstTmp = new List <PointF>()
{
point1, point2, point3, point4
};
List <PointF> lstPoint = new List <PointF>();
foreach (PointF point in lstTmp)
{
//判断点是否合理
if (CheckPointIsValid(point))
{
lstPoint.Add(point);
}
}
if (lstPoint.Count() < 2)
{
//如果点的个数小于2，不能绘制直线
return(false);
}
//将刻度点，转换成像素点
List <PointF> lstPixlsPoint = ConvertScaleToPixls(lstPoint);
g.DrawLine(new Pen(lineColor, lineWidth), lstPixlsPoint[0], lstPixlsPoint[1]);
g.DrawString(string.Format("L{0}", index), t_Font, Brushes.Black, new PointF(lstPixlsPoint[1].X + 2, lstPixlsPoint[1].Y - 2));
this.label1.Text += string.Format("L{0}:{1}x+{2}y+{3}=0 ; ", index, linear.A, linear.B, linear.C);
index++;
return(true);
}
/// <summary>
/// 判断直线方程是否在坐标轴范围内
/// </summary>
/// <param name="linear"></param>
/// <returns></returns>
public bool CheckLineIsValid(LinearEquation linear)
{
bool flagX = false;
bool flagY = false;
var y = linear.GetValueFromX(0f);
//判断y坐标的值有没有越界
if (y == float.MaxValue)
{
//表示是垂直于x轴的直线
var x0 = -linear.C * 1.0f / linear.A;
if (x0 >= 0 - this._AxisX.Max && x0 < this._AxisX.Max)
{
flagY = true;
}
else
{
flagY = false;
}
}
else
{
if (y <= this._AxisY.Max && y >= 0 - this._AxisY.Max)
{
flagY = true;
}
else
{
flagY = false;
}
}
//判断x坐标的值
var x = linear.GetValueFromY(0f);
if (x == float.MaxValue)
{
var y0 = -linear.C * 1.0f / linear.B;
if (y0 <= this._AxisY.Max && y0 >= 0 - this._AxisY.Max)
{
flagX = true;
}
else
{
flagX = false;
}
}
else
{
if (x <= this._AxisX.Max && x >= 0 - this._AxisX.Max)
{
flagX = true;
}
else
{
flagX = false;
}
}
return(flagX && flagY);//只有x,y都满足条件，才是有效的
}
