CairoContext::arcNegative()

(PECL cairo >= 0.1.0)

Adds a negative arc

说明

面向对象风格(method):

publicCairoContext::arcNegative(float $x,float $y,float $radius,float $angle1,float $angle2): void

过程化风格:

cairo_arc_negative(CairoContext$context,float $x,float $y,float $radius,float $angle1,float $angle2): void

Adds a circular arc of the given$radiusto the current path. The arc is centered at($x,$y), begins at$angle1and proceeds in the direction of decreasing angles to end at$angle2. If$angle2is greater than$angle1it will be progressively decreased by 2*M_PI until it is less than$angle1. See CairoContext::arc() or cairo_arc() for more details. This function differs only in the direction of the arc between the two angles.

参数

$context

A valid CairoContext object

$x

double x position

$y

double y position

$radius

The radius of the desired negative arc

$angle1

Start angle of the arc

$angle2

End angle of the arc

返回值

没有返回值。

范例

Example #1 面向对象风格

<?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->arcNegative(50, 50, $r, 2 * M_PI, 0);
 $c->stroke();
 $c->fill();
}
$s->writeToPng(dirname(__FILE__) . '/CairoContext__arcNegative.png');
?>

Example #2 过程化风格

<?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; $r -= 10) {
 cairo_arc_negative($c, 50, 50, $r, 2 * M_PI, 0);
 cairo_stroke($c);
 cairo_fill($c);
}
cairo_surface_write_to_png($s, dirname(__FILE__) . '/cairo_arc_negative.png');
?>

参见

• CairoContext::arc() Adds a circular arc