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Update webkit2png.py
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Improved comments, examples removed from comments
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@itsnauman
itsnauman committed Apr 26, 2014
1 parent f540012 commit bd11af8
Showing 1 changed file with 39 additions and 63 deletions.
102 changes: 39 additions & 63 deletions webkit2png/webkit2png.py
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,7 @@
#
# Creates screenshots of webpages using by QtWebkit.
#
# Copyright (c) 2008 Roland Tapken <[email protected]>
# Copyright (c) 2014 Roland Tapken <[email protected]>
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
Expand Down Expand Up @@ -33,63 +33,18 @@
# Class for Website-Rendering. Uses QWebPage, which
# requires a running QtGui to work.
class WebkitRenderer(QObject):
"""A class that helps to create 'screenshots' of webpages using
"""
A class that helps to create 'screenshots' of webpages using
Qt's QWebkit. Requires PyQt4 library.
Use "render()" to get a 'QImage' object, render_to_bytes() to get the
resulting image as 'str' object or render_to_file() to write the image
directly into a 'file' resource.
These methods have to be called from within Qt's main (GUI) thread.
An example on how to use this is the __qt_main() method at the end
of the libraries source file. More generic examples:
def qt_main():
while go_on():
do_something_meaningful()
while QApplication.hasPendingEvents():
QApplication.processEvents()
QApplication.quit()
app = init_qtgui()
QTimer.singleShot(0, qt_main)
sys.exit(app.exec_())
Or let Qt handle event processing using a QTimer instance:
def qt_main_loop():
if not go_on():
QApplication.quit()
return
do_something_meaningful()
app = init_qtgui()
main_timer = QTimer()
QObject.connect(main_timer, QtCore.SIGNAL("timeout()"), qt_main_loop)
sys.exit(app.exec_())
Avaible properties:
width -- The width of the "browser" window. 0 means autodetect (default).
height -- The height of the window. 0 means autodetect (default).
timeout -- Seconds after that the request is aborted (default: 0)
wait -- Seconds to wait after loading has been finished (default: 0)
scaleToWidth -- The resulting image is scaled to this width.
scaleToHeight -- The resulting image is scaled to this height.
scaleRatio -- The image is scaled using this method. Possible values are:
keep
expand
crop
ignore
grabWhileWindow -- If this is True a screenshot of the whole window is taken. Otherwise only the current frame is rendered. This is required for plugins to be visible, but it is possible that another window overlays the current one while the screenshot is taken. To reduce this possibility, the window is activated just before it is rendered if this property is set to True (default: False).
qWebSettings -- Settings that should be assigned to the created QWebPage instance. See http://doc.trolltech.com/4.6/qwebsettings.html for possible keys. Defaults:
JavascriptEnabled: False
PluginsEnabled: False
PrivateBrowsingEnabled: True
JavascriptCanOpenWindows: False
"""

def __init__(self,**kwargs):
"""Sets default values for the properties."""
"""
Sets default values for the properties.
"""

if not QApplication.instance():
raise RuntimeError(self.__class__.__name__ + " requires a running QApplication instance")
Expand All @@ -105,6 +60,7 @@ def __init__(self,**kwargs):
self.scaleRatio = kwargs.get('scaleRatio', 'keep')
self.format = kwargs.get('format', 'png')
self.logger = kwargs.get('logger', None)

# Set this to true if you want to capture flash.
# Not that your desktop must be large enough for
# fitting the whole window.
Expand All @@ -127,7 +83,9 @@ def __init__(self,**kwargs):


def render(self, url):
"""Renders the given URL into a QImage object"""
"""
Renders the given URL into a QImage object
"""
# We have to use this helper object because
# QApplication.processEvents may be called, causing
# this method to get called while it has not returned yet.
Expand All @@ -143,7 +101,8 @@ def render(self, url):
return image

def render_to_file(self, url, file_object):
"""Renders the image into a File resource.
"""
Renders the image into a File resource.
Returns the size of the data that has been written.
"""
format = self.format # this may not be constant due to processEvents()
Expand Down Expand Up @@ -175,13 +134,15 @@ def setAllCookies(self, cookieList):
QNetworkCookieJar.setAllCookies(self, cookieList)

class _WebkitRendererHelper(QObject):
"""This helper class is doing the real work. It is required to
"""
This helper class is doing the real work. It is required to
allow WebkitRenderer.render() to be called "asynchronously"
(but always from Qt's GUI thread).
"""

def __init__(self, parent):
"""Copies the properties from the parent (WebkitRenderer) object,
"""
Copies the properties from the parent (WebkitRenderer) object,
creates the required instances of QWebPage, QWebView and QMainWindow
and registers some Slots.
"""
Expand Down Expand Up @@ -219,14 +180,17 @@ def __init__(self, parent):
self._window.show()

def __del__(self):
"""Clean up Qt4 objects. """
"""
Clean up Qt4 objects.
"""
self._window.close()
del self._window
del self._view
del self._page

def render(self, url):
"""The real worker. Loads the page (_load_page) and awaits
"""
The real worker. Loads the page (_load_page) and awaits
the end of the given 'delay'. While it is waiting outstanding
QApplication events are processed.
After the given delay, the Window or Widget (depends
Expand Down Expand Up @@ -312,7 +276,8 @@ def _load_page(self, url, width, height, timeout):
self._window.resize(size)

def _post_process_image(self, qImage):
"""If 'scaleToWidth' or 'scaleToHeight' are set to a value
"""
If 'scaleToWidth' or 'scaleToHeight' are set to a value
greater than zero this method will scale the image
using the method defined in 'scaleRatio'.
"""
Expand All @@ -330,12 +295,16 @@ def _post_process_image(self, qImage):
return qImage

def _on_each_reply(self,reply):
"""Logs each requested uri"""
"""
Logs each requested uri
"""
self.logger.debug("Received %s" % (reply.url().toString()))

# Eventhandler for "loadStarted()" signal
def _on_load_started(self):
"""Slot that sets the '__loading' property to true."""
"""
Slot that sets the '__loading' property to true
"""
if self.logger: self.logger.debug("loading started")
self.__loading = True

Expand All @@ -350,14 +319,19 @@ def _on_load_finished(self, result):

# Eventhandler for "sslErrors(QNetworkReply *,const QList<QSslError>&)" signal
def _on_ssl_errors(self, reply, errors):
"""Slot that writes SSL warnings into the log but ignores them."""
"""
Slot that writes SSL warnings into the log but ignores them.
"""
for e in errors:
if self.logger: self.logger.warn("SSL: " + e.errorString())
reply.ignoreSslErrors()


class CustomWebPage(QWebPage):
def __init__(self, **kwargs):
"""
Class Initializer
"""
super(CustomWebPage, self).__init__()
self.logger = kwargs.get('logger', None)
self.ignore_alert = kwargs.get('ignore_alert', True)
Expand All @@ -378,7 +352,8 @@ def javaScriptConfirm(self, frame, message):
return False

def javaScriptPrompt(self, frame, message, default, result):
"""This function is called whenever a JavaScript program running inside frame tries to prompt
"""
This function is called whenever a JavaScript program running inside frame tries to prompt
the user for input. The program may provide an optional message, msg, as well as a default value
for the input in defaultValue.
Expand All @@ -394,7 +369,8 @@ def javaScriptPrompt(self, frame, message, default, result):
return False

def shouldInterruptJavaScript(self):
"""This function is called when a JavaScript program is running for a long period of time.
"""
This function is called when a JavaScript program is running for a long period of time.
If the user wanted to stop the JavaScript the implementation should return true; otherwise false.
"""
if self.logger: self.logger.debug("WebKit ask to interrupt JavaScript")
Expand Down

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