vades

Fixing "Expression has changed after it was checked" in Angular

The exception appears (in the development mode) at the moment the value is checked and value is different of the updated value.

Error message example

AppComponent.html:1 ERROR Error: ExpressionChangedAfterItHasBeenCheckedError: Expression has changed after it was checked. Previous value: 'ngIf: true'. Current value: 'ngIf: false'.
    at viewDebugError (core.js:20440)
    at expressionChangedAfterItHasBeenCheckedError (core.js:20428)
    at checkBindingNoChanges (core.js:20530)

smex

from PyQt4.QtGui import QImage, qRgb
import numpy as np

class NotImplementedException:
    pass

gray_color_table = [qRgb(i, i, i) for i in range(256)]

def toQImage(im, copy=False):
    if im is None: