CairoContext::clipPreserve()

(PECL cairo >= 0.1.0)

Establishes a new clip region from the current clip

说明

面向对象风格(method):

publicCairoContext::clipPreserve(void): void

过程化风格:

cairo_clip_preserve(CairoContext$context): void

Establishes a new clip region by intersecting the current clip region with the current path as it would be filled by Context.fill() and according to the current FILL RULE(see CairoContext::setFillRule() or cairo_set_fill_rule()).

Unlike CairoContext::clip(),CairoContext::clipPreserve() preserves the path within the Context. The current clip region affects all drawing operations by effectively masking out any changes to the surface that are outside the current clip region.

Calling CairoContext::clipPreserve() can only make the clip region smaller, never larger. But the current clip is part of the graphics state, so a temporary restriction of the clip region can be achieved by calling CairoContext::clipPreserve() within a CairoContext::save()/CairoContext::restore() pair. The only other means of increasing the size of the clip region is CairoContext::resetClip().

参数

$context

A valid CairoContext object

返回值

没有返回值。

范例

Example #1 面向对象风格

<?php
$surface = new CairoImageSurface(CairoFormat::ARGB32, 50, 50);
$context = new CairoContext($surface);
$context->clipPreserve();
?>

Example #2 过程化风格

<?php
$surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, 50, 50);
$context = cairo_create($surface);
cairo_clip_preserve($context);
?>

参见

• CairoContext::save() The save purpose
• CairoContext::restore() The restore purpose
• CairoContext::resetClip() The resetClip purpose