c++ - 画线算法

Question

我使用 wu 技术编写了一个画线算法。它有效但有问题。见下文。

我想知道是否有人解决了绘制抗锯齿线的问题？令人惊讶的是，谷歌搜索结果没有令人满意的算法。有很多讨论，但没有一个完整的、健壮的算法，独立于对图形库的任何依赖。

如果有人想要以下函数的示例代码，请告诉我。我希望用更强大的功能替换它，但我还没有找到。我确信我的算法可以改进，但它确实有效。

struct xya{    int x;    int y;     uint8_t a;    xya(int x=0, int y=0, uint8_t a=0) : x(x), y(y), a(a) {}};inline void wuline(xya*& out, int x0, int y0, int x1, int y1){    short DeltaX, DeltaY, XDir;    static const int intensity = 8;    if (y0 > y1)    {        short Temp = y0;         y0 = y1;         y1 = Temp;        Temp = x0;         x0 = x1;         x1 = Temp;    }    *out++ = xya(x0,y0,255);    if ((DeltaX = x1 - x0) >= 0)    {        XDir = 1;    }     else     {        XDir = -1;        DeltaX = -DeltaX;     }    if ((DeltaY = y1 - y0) == 0)    {        while (DeltaX-- != 0)         {            x0 += XDir;            *out++ = xya(x0,y0,255);                    }        return;    }    if (DeltaX == 0)     {        do         {            y0++;            *out++ = xya(x0,y0,255);                    }         while (--DeltaY != 0);        return;    }    if (DeltaX == DeltaY)     {        do         {            x0 += XDir;            y0++;            *out++ = xya(x0,y0,255);                    }         while (--DeltaY != 0);        return;    }    if (DeltaY > DeltaX)     {        unsigned short ErrorAcc = 0;          unsigned short ErrorAdj = ((unsigned long) DeltaX > intensity;            *out++ = xya(x0,y0,Weighting ^ 255);            *out++ = xya(x0+XDir,y0,Weighting);        }        *out++ = xya(x1,y1,255);                }    else    {        unsigned short ErrorAcc = 0;          unsigned short ErrorAdj = ((unsigned long) DeltaY > intensity;            *out++ = xya(x0,y0,Weighting ^ 255);                        *out++ = xya(x0,y0+1,Weighting);        }        *out++ = xya(x1,y1,255);    }}

Answer 1

快速有效地绘制抗锯齿线的典型示例是 Xiaolin Wu's algorithm 。您可能需要查看它以获得可靠的方法。这是 some sample code ， 也。右图应用吴氏算法的结果:

alt text http://www.suchit-tiwari.org/writings/antialias/antialias.png