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CairoContext::arcNegative

cairo_arc_negative

(PECL cairo >= 0.1.0)

CairoContext::arcNegative -- cairo_arc_negative — Adds a negative arc

说明

面向对象风格 (method):

public CairoContext::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 radius to the current path. The arc is centered at (x, y), begins at angle1 and proceeds in the direction of decreasing angles to end at angle2. If angle2 is greater than angle1 it 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