How to draw a circle

[GapiNewb]

Ok, i'm totally new to Gapidraw and don't know anything about MFC. I was wondering how i can draw a circle on a CGapiSurface.

[okku]

GapiDraw dosen't have any drawing capabilities what i am aware of. You have to do it by yourself. Simply by setting the pixels by hand.

Search for "circle drawing algorithm" on google and you will find code and examples.

[Kzinti]

PocketFrog has the circle drawing algorithm implemented (and many others). Take a look at the available source code.

[Eicke]

void DrawCircle(int nX, int nY, int nR, COLORREF Color)
{
int x,y,dt,dt1,dt2,dr;
x=0;y=nR;dt=2-nR-nR;
while(y>=0)
{
//SetPixelColor is a draw point fun
SetPixelColor(nX+x,nY+y,Color);
SetPixelColor(nX+x,nY-y,Color);
SetPixelColor(nX-x,nY+y,Color);
SetPixelColor(nX-x,nY-y,Color);
if(dt<0)
{
dt1=dt+dt+y+y-1;
if(dt1<=0)dr=1;
else dr=2;
}
else if(dt>0)
{
dt2=dt+dt-x-x-1;
if(dt2<=0)dr=2;
else dr=3;
}else dr=2;
switch(dr)
{
case 1: x++;dt+=x+x+1;
break;
case 2: x++;y--;dt+=x+x-y-y-1;
break;
case 3: y--;dt+=1-y-y;
break;
}
}
}

[GapiNewb]

thank you so much

[sarafreelancer]

Hi,

Thanks for posting circle drawing logic. If i wanted to draw a circle in CGapiSurface, how can i call the method DrawCircle? and how to associate with CGapiSurface

and there are some method call like SetPixelColor, what is that? where is the definition of that

simply i need a complete example, how circle can be drawn on the CGapiSurface

Thanks