CairoContext::appendPathCairoContext::arc
cairo_arc
(PECL cairo >= 0.1.0)
CairoContext::arc -- cairo_arc — Adds a circular arc
Descrição
Estilo orientado a objetos (method):
Estilo de procedimentos:
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 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() before calling CairoContext::arc() or cairo_arc(). 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() to get the arc in the direction of decreasing angles.
Parâmetros
- context
-
A valid CairoContext object
- x
-
x position
- y
-
y position
- radius
-
Radius of the arc
- angle1
-
start angle
- angle2
-
end angle
Valor Retornado
Não há valor retornado.
Exemplos
Exemplo #1 Estilo orientado a objetos
<?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');
?>
Exemplo #2 Estilo de procedimentos
<?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');
?>
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User Contributed Notes
CairoContext::arc