Example Feature Request

[cpd67]

I was looking into maybe having a drawEllipse() method for drawing ellipses onto a Canvas. Can anyone help me out on this?

[Rycieos]

Bored at work, note this hasn't been tested or checked, so please do both. So here we go:

From our Canvas.cpp, Canvas::drawCircle:

void Canvas::drawCircle(int xverts, int yverts, int radius, int sides, ColorFloat color, bool filled) {
    float delta = 2.0f / sides * PI;
    if (filled) {
        ConvexPolygon *s = new ConvexPolygon(sides);
        for (int i = 0; i < sides; ++i)
            s->addVertex(xverts+radius*cos(i*delta), yverts+radius*sin(i*delta),color);
        drawShape(s);
    } else {
        float oldX = 0, oldY = 0, newX = 0, newY = 0;
        Polyline *p = new Polyline(sides+1);
        for (int i = 0; i <= sides; ++i) {
            oldX = newX; oldY = newY;
            newX = xverts+radius*cos(i*delta);
            newY = yverts+radius*sin(i*delta);
            if (i > 0)
                p->addNextVertex(oldX, oldY,color);
        }
        p->addNextVertex(newX, newY,color);
        drawShape(p);
    }
}

Therefore, since we just do a loop and make such vertexes for each "side", we can do the same for an elipse, we just need to do trig for the distances. Make a drawEllipse() like so:

void Canvas::drawEllipse(int xverts, int yverts, int xradius, int yradius, int sides, ColorFloat color, bool filled) {
    float delta = 2.0f / sides * PI;
    if (filled) {
        ConvexPolygon *s = new ConvexPolygon(sides);
        for (int i = 0; i < sides; ++i)
            s->addVertex(xverts+xradius*cos(i*delta), yverts+yradius*sin(i*delta),color);
        drawShape(s);
    } else {
        float oldX = 0, oldY = 0, newX = 0, newY = 0;
        Polyline *p = new Polyline(sides+1);
        for (int i = 0; i <= sides; ++i) {
            oldX = newX; oldY = newY;
            newX = xverts+xradius*cos(i*delta);
            newY = yverts+yradius*sin(i*delta);
            if (i > 0)
                p->addNextVertex(oldX, oldY,color);
        }
        p->addNextVertex(newX, newY,color);
        drawShape(p);
    }
}

Also, maybe change drawCircle to use drawEllipse to save code? Shouldn't be much slower if any. Like such:

void Canvas::drawCircle(int xverts, int yverts, int radius, int sides, ColorFloat color, bool filled) {
    drawEllipse(xverts, yverts, radius, radius, sides, color, filled);
}

[cpd67]

Thanks a ton!