CAIRO_CLIP(3) 1 CAIRO_CLIP(3)CairoContext::clip - Establishes a new clip region
Object oriented style (method):
SYNOPSIS
public void CairoContext::clip (void )
DESCRIPTION
Procedural style:
void cairo_clip (CairoContext $context)
Establishes a new clip region by intersecting the current clip region with the current path as it would be filled by CairoContext::fill or
cairo_fill(3) and according to the current fill rule (see CairoContext::setFillRule or cairo_set_fill_rule(3)).
After CairoContext::clip or cairo_clip(3), the current path will be cleared from the cairo 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::clip or cairo_clip(3) 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::clip or cairo_clip(3) within a
CairoContext::save/ CairoContext::restore or cairo_save(3)/cairo_restore(3) pair. The only other means of increasing the size of the clip
region is CairoContext::resetClip or procedural cairo_reset_clip(3).
PARAMETERS
o $context
- A valid CairoContext object
RETURN VALUES
No value is returned.
EXAMPLES
Example #1
Object oriented style
<?php
$surface = new CairoImageSurface(CairoFormat::ARGB32, 50, 50);
$context = new CairoContext($surface);
$context->clip();
?>
Example #2
Procedural style
<?php
$surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, 50, 50);
$context = cairo_create($surface);
cairo_clip($context);
?>
SEE ALSO
CairoContext::resetClip, cairo_reset_clip(3).
PHP Documentation Group CAIRO_CLIP(3)
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CAIRO_ARC(3) 1 CAIRO_ARC(3)CairoContext::arc - Adds a circular arc
Object oriented style (method):
SYNOPSIS
public void CairoContext::arc (float $x, float $y, float $radius, float $angle1, float $angle2)
DESCRIPTION
Procedural style:
void cairo_arc (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 direc-
tion 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(3) before calling CairoContext::arc or cairo_arc(3). 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(3) to get the arc in the direction of decreasing
angles.
PARAMETERS
o $context
- A valid CairoContext object
o $x
- x position
o $y
- y position
o $radius
- Radius of the arc
o $angle1
- start angle
o $angle2
- end angle
RETURN VALUES
No value is returned.
EXAMPLES
Example #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->arc(50, 50, $r, 0, 2 * M_PI);
$c->stroke();
$c->fill();
}
$s->writeToPng(dirname(__FILE__) . '/CairoContext__arc.png');
?>
Example #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; $r -= 10) {
cairo_arc($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');
?>
SEE ALSO
CairoContext::arcNegative.
PHP Documentation Group CAIRO_ARC(3)