Adds a negative arc

Описание

Object oriented style (method):

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

Procedural style:

void cairo_arc_negative ( 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 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.

Список параметров

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

Возвращаемые значения

Эта функция не возвращает значения после выполнения.

Примеры

Пример #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->arcNegative(50, 50, $r, 2 * M_PI, 0);
 $c->stroke();
 $c->fill();
}

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

Пример #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; $r -= 10) {
 cairo_arc_negative($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');
?>

Смотрите также

CairoContext::arc() - Adds a circular arc