The C language does not provide any support for graphics as standard. C is designed to be as generic as possible, but graphics are a system-specific feature. To use graphics in C you need a third-party graphics library that supports your operating system and hardware, however generic libraries such as OpenGL are available. Nevertheless, it is not possible to draw curves, you can only approximate a curve using a series of short lines. The shorter the lines and the higher the resolution, the smoother the curve will appear.
Assuming you have access to an OpenGL library, you can draw an ellipse as follows:
void DrawEllipse(float cx, float cy, float rx, float ry, int num_segments)
{
const float pi = atan (1) * 4;
float theta = 2 * pi / float (num_segments);
float c = cosf (theta);
float s = sinf (theta);
float x = 1;
float y = 0;
float t;
glBegin (GL_LINE_LOOP);
for (int i = 0; i < num_segments; ++i)
{
glVertex2 f (x * rx + cx, y * ry + cy);
t = x;
x = c * x - s * y;
y = s * t + c * y;
}
glEnd();
}
Chat with our AI personalities
isn't it an arty word, like when you draw an ellipse-- so when you see/draw something with an ellipse you call it an elliptical drawing
One can create a perfect ellipse using two pins on a piece of string and a pencil. Place the pins at opposite sides and then loop the string around them. Finally place the pencil in the loops and pull it around the pins to draw the ellipse.
Circular segment
A circle is perfectly round, and has one center. An ellipse is like a circle with TWO "centers", and each "center" is called a "focus". The plural of "focus" is "foci". Take a piece of string and tie a loop in each end. Put a pin through the loops, and hold it still in the center of the circle. Place the tip of your pencil at the center of the string, and you can draw a circle by keeping the string taut. Now take TWO pins, and put one pin at each end of the string; place the pins at some short distance apart, and hold them there. Place your pencil and draw, and the shape you draw will be an ellipse. The two pinpoints are the focuses, or foci, of the ellipse. Eccentricity is a measure of how far the ellipse varies from a circle. An ellipse with an eccentricity of zero _IS_ a circle, while an eccentricity of 1.0 is a straight line, with that string stretched out straight. In astronomy, every natural orbit is an ellipse.
He is credited with introducing the words: ellipse, parabola and hyperbola.