php man page for cairo_arc

CAIRO_ARC(3)								 1							      CAIRO_ARC(3)

CairoContext::arc - Adds a circular arc

       Object oriented style (method):

SYNOPSIS
       public void CairoContext::arc (float  $x, float	$y, float  $radius, float  $angle1, float  $angle2)

DESCRIPTION
       Procedural style:
       void cairo_arc (CairoContext  $context, float  $x, float  $y, float  $radius, float  $angle1, float  $angle2)

	Adds a circular arc of the given radius to the current path. The arc is centered at ($x, $y), begins at $angle1 and proceeds in the direc-
       tion of increasing angles to end at $angle2. If $angle2 is less than $angle1 it will be progressively  increased  by  2*M_PI  until  it	is
       greater	than  $angle1.	If there is a current point, an initial line segment will be added to the path to connect the current point to the
       beginning of the arc.  If  this	initial  line  is  undesired,  it  can	be  avoided  by  calling  CairoContext::newSubPath  or	procedural
       cairo_new_sub_path(3) before calling CairoContext::arc or cairo_arc(3). Angles are measured in radians. An angle of 0.0 is in the direction
       of the positive X axis (in user space). An angle of M_PI/2.0 radians (90 degrees) is in the direction of  the  positive	Y  axis  (in  user
       space).	Angles	increase  in the direction from the positive X axis toward the positive Y axis. So with the default transformation matrix,
       angles increase in a clockwise direction. (To convert from degrees to radians, use degrees * (M_PI / 180.).) This function gives the arc in
       the  direction  of  increasing angles; see CairoContext::arcNegative or cairo_arc_negative(3) to get the arc in the direction of decreasing
       angles.

PARAMETERS
	      o $context
		- A valid CairoContext object

	      o $x
		- x position

	      o $y
		- y position

	      o $radius
		- Radius of the arc

	      o $angle1
		- start angle

	      o $angle2
		- end angle

RETURN VALUES
	No value is returned.

EXAMPLES
       Example #1

	      Object oriented style

	      <?php

	      $s = new CairoImageSurface(CairoFormat::ARGB32, 100, 100);
	      $c = new CairoContext($s);

	      $c->setSourceRgb(0, 0, 0);
	      $c->paint();

	      $c->setLineWidth(1);
	      $c->setSourceRgb(1, 1, 1);

	      for ($r = 50; $r > 0; $r -= 10) {
	       $c->arc(50, 50, $r, 0, 2 * M_PI);
	       $c->stroke();
	       $c->fill();
	      }

	      $s->writeToPng(dirname(__FILE__) . '/CairoContext__arc.png');
	      ?>

       Example #2

	      Procedural style

	      <?php

	      $s = cairo_image_surface_create(CAIRO_SURFACE_TYPE_IMAGE, 100, 100);
	      $c = cairo_create($s);

	      cairo_set_source_rgb($c, 0, 0, 0);
	      cairo_paint($c);

	      cairo_set_source_rgb($c, 1, 1, 1);
	      cairo_set_line_width($c, 1);

	      for ($r = 50; $r > 0; $r -= 10) {
	       cairo_arc($c, 50, 50, $r, 0, 2 * M_PI);
	       cairo_stroke($c);
	       cairo_fill($c);
	      }

	      cairo_surface_write_to_png($s, dirname(__FILE__) . '/cairo_arc.png');
	      ?>

SEE ALSO
       CairoContext::arcNegative.

PHP Documentation Group 													      CAIRO_ARC(3)