DZone Snippets: circle code

Create and drag circles in SVG

jrobertson (James Robertson) — Sat, 22 Mar 2008 00:30:36 GMT

Demonstrates creating creating and dragging circles using SVG and ECMAScript.

Tested on Firefox 3 beta 4.

file: makeDragDrop.svg



		xmlns:xlink="http://www.w3.org/1999/xlink" >





Click something to move it

Click nothing to add something

Source file copied from http://srufaculty.sru.edu/david.dailey/svg/makeDragDrop.svg

Circulos en Allegro

jcongote (John Edgar Congote Calle) — Fri, 22 Sep 2006 20:06:14 GMT

Un codigo para dibujar un circulo en allegro con degradado



#include 



void init();

void deinit();



int main() {

	int cont;

    

    init();

	

	

	for (cont=0;cont<255;cont++){

        circlefill(screen,320,240,255-cont,makecol(cont,0,0));

    }



	while (!key[KEY_ESC]) {

		/* put your code here */

	}



	deinit();

	return 0;

}

END_OF_MAIN();



void init() {

	int depth, res;

	allegro_init();

	depth = desktop_color_depth();

	if (depth == 0) depth = 32;

	set_color_depth(depth);

	res = set_gfx_mode(GFX_AUTODETECT_WINDOWED, 640, 480, 0, 0);

	if (res != 0) {

		allegro_message(allegro_error);

		exit(-1);

	}



	install_timer();

	install_keyboard();

	install_mouse();

	/* add other initializations here */

}



void deinit() {

	clear_keybuf();

	/* add other deinitializations here */

}

Closest Circle Point //JavaScript Function

jonasraoni (Jonas Raoni Soares Silva) — Fri, 09 Sep 2005 04:36:55 GMT

Given a dot and a circle, it returns the nearest dot over the circle.

[UPDATED CODE AND HELP CAN BE FOUND HERE]



//+ Jonas Raoni Soares Silva

//@ http://jsfromhell.com/math/closest-circle-point [v1.0]



closestCirclePoint = function( px, py, x, y, ray ){

	var tg = ( x += ray, y += ray, 0 );

	return function( x, y, x0, y0 ){ return Math.sqrt( ( x -= x0 ) * x + ( y -= y0 ) * y );	}( px, py, x, y ) > ray ?

		{ x: Math.cos( tg = Math.atan2( py - y, px - x ) ) * ray + x, y: Math.sin( tg ) * ray + y }

		//{ x: ( px - x ) / ( length / ray ) + x, y: ( py - y ) / ( length / ray ) + y }

		: { x: px, y: py };

};

drawing circle function

korakot (Korakot Chaovavanich) — Wed, 22 Jun 2005 17:56:10 GMT

Just to make drawing a circle easier.
Here is a function that will draw yellow circle with black outline.



# from appuifw import *

# c = Canvas()

# app.body = c



def circle(x,y,radius=5, outline=0, fill=0xffff00, width=1):

  c.ellipse((x-radius, y-radius, x+radius, y+radius), outline, fill, width)

You may use other default values.

Then I create a function to show circles randomly

import e32

from random import randint, choice



sleep = e32.ao_sleep

colors = [0xff0000, 0x00ff00, 0x0000ff, 0xffff00, 0xffffff]



def rand_circle(n):

  c.clear()

  for i in range(n):

    circle(randint(0,176), randint(0,144), randint(5,20), fill=choice(colors))

    sleep(0.1)



# now show it

rand_circle(30)