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# -*- coding: utf-8 -*-
# Copyright (c) Vispy Development Team. All Rights Reserved.
# Distributed under the (new) BSD License. See LICENSE.txt for more info.
from .base_filter import Filter
from ..transforms import NullTransform
from ...geometry import Rect
class Clipper(Filter):
"""Clips visual output to a rectangular region."""
FRAG_SHADER = """
void clip() {
vec4 pos = $fb_to_clip(gl_FragCoord);
if( pos.x < $view.x || pos.x > $view.y ||
pos.y < $view.z || pos.y > $view.w ) {
discard;
}
}
"""
def __init__(self, bounds=(0, 0, 1, 1), transform=None):
super(Clipper, self).__init__(fcode=self.FRAG_SHADER,
fhook='pre', fpos=1)
self.bounds = bounds # (x, y, w, h)
if transform is None:
transform = NullTransform()
self._transform = None
self.transform = transform
@property
def bounds(self):
"""The clipping boundaries.
This must be a tuple (x, y, w, h) in a clipping coordinate system
that is defined by the `transform` property.
"""
return self._bounds
@bounds.setter
def bounds(self, b):
self._bounds = Rect(b).normalized()
b = self._bounds
self.fshader['view'] = (b.left, b.right, b.bottom, b.top)
@property
def transform(self):
"""The transform that maps from framebuffer coordinates to clipping
coordinates.
"""
return self._transform
@transform.setter
def transform(self, tr):
if tr is self._transform:
return
self._transform = tr
self.fshader['fb_to_clip'] = tr
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