CairoContext::arcNegative()
(PECL cairo >= 0.1.0)
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 $angle2): void
Adds a circular arc of the given$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