PS_ARC(3) 1 PS_ARC(3)ps_arc - Draws an arc counterclockwiseSYNOPSIS
bool ps_arc (resource $psdoc, float $x, float $y, float $radius, float $alpha, float $beta)
DESCRIPTION
Draws a portion of a circle with at middle point at ($x, $y). The arc starts at an angle of $alpha and ends at an angle of $beta. It is
drawn counterclockwise (use ps_arcn(3) to draw clockwise). The subpath added to the current path starts on the arc at angle $alpha and ends
on the arc at angle $beta.
PARAMETERS
o $psdoc
- Resource identifier of the postscript file as returned by ps_new(3).
o $x
- The x-coordinate of the circle's middle point.
o $y
- The y-coordinate of the circle's middle point.
o $radius
- The radius of the circle
o $alpha
- The start angle given in degrees.
o $beta
- The end angle given in degrees.
RETURN VALUES
Returns TRUE on success or FALSE on failure.
SEE ALSO ps_arcn(3).
PHP Documentation Group PS_ARC(3)
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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)