CairoContext::curveTo()

(PECL cairo >= 0.1.0)

Adds a curve

说明

面向对象风格(method):

publicCairoContext::curveTo(float $x1,float $y1,float $x2,float $y2,float $x3,float $y3): void

过程化风格:

cairo_curve_to(CairoContext$context,float $x1,float $y1,float $x2,float $y2,float $x3,float $y3): void

Adds a cubic Bezier spline to the path from the current point to position$x3,$y3in user-space coordinates, using$x1,$y1and$x2,$y2as the control points. After this call the current point will be$x3,$y3.

If there is no current point before the call to CairoContext::curveTo() this function will behave as if preceded by a call to CairoContext::moveTo()($x1,$y1).

参数

$context

A valid CairoContext object created with CairoContext::__construct() or cairo_create()

$x1

First control point in the x axis for the curve

$y1

First control point in the y axis for the curve

$x2

Second control point in x axis for the curve

$y2

Second control point in y axis for the curve

$x3

Final point in the x axis for the curve

$y3

Final point in the y axis for the curve

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->moveTo(10, 50); 
$c->setLineWidth(5);
$c->setSourceRgb(.1, 0, 1);
$c->curveTo(20, 80, 80, 20, 90, 50); 
$c->stroke();
$s->writeToPng(dirname(__FILE__) . '/curveTo.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_move_to($c, 10, 50);
cairo_set_line_width($c, 5);
cairo_set_source_rgb($c, .1, 0, 1);
cairo_curve_to($c, 20, 80, 80, 20, 90, 50);
cairo_stroke($c);
cairo_surface_write_to_png($s, dirname(__FILE__) . '/curve_to.png');
?>

参见

• CairoContext::moveTo() The moveTo purpose