Helpviewer/HelpTabBar.py

# -*- coding: utf-8 -*-

# Copyright (c) 2010 - 2012 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Module implementing a specialized tab bar for the web browser.
"""

from PyQt4.QtCore import Qt, QPoint, QTimer, QEvent
from PyQt4.QtGui import QFrame, QLabel

from E5Gui.E5TabWidget import E5WheelTabBar
from E5Gui.E5PassivePopup import E5PassivePopup

from .HelpSnap import renderTabPreview

import Preferences


class HelpTabBar(E5WheelTabBar):
    """
    Class implementing the tab bar of the web browser.
    """
    def __init__(self, parent=None):
        """
        Constructor
        
        @param parent reference to the parent widget (HelpTabWidget)
        """
        E5WheelTabBar.__init__(self, parent)
        
        self.__tabWidget = parent
        
        self.__previewPopup = None
        self.__currentTabPreviewIndex = -1
        
        self.setMouseTracking(True)
    
    def __showTabPreview(self):
        """
        Private slot to show the tab preview.
        """
        indexedBrowser = self.__tabWidget.browserAt(self.__currentTabPreviewIndex)
        currentBrowser = self.__tabWidget.currentBrowser()
        
        if indexedBrowser is None or currentBrowser is None:
            return
        
        # no previews during load
        if indexedBrowser.progress() != 0:
            return
        
        w = self.tabSizeHint(self.__currentTabPreviewIndex).width()
        h = int(w * currentBrowser.height() / currentBrowser.width())
        
        self.__previewPopup = E5PassivePopup(self)
        self.__previewPopup.setFrameShape(QFrame.StyledPanel)
        self.__previewPopup.setFrameShadow(QFrame.Plain)
        self.__previewPopup.setFixedSize(w, h)
        
        l = QLabel()
        l.setPixmap(renderTabPreview(indexedBrowser.page(), w, h))
        
        self.__previewPopup.setView(l)
        self.__previewPopup.layout().setAlignment(Qt.AlignTop)
        self.__previewPopup.layout().setMargin(0)
        
        tr = self.tabRect(self.__currentTabPreviewIndex)
        pos = QPoint(tr.x(), tr.y() + tr.height())
        
        self.__previewPopup.show(self.mapToGlobal(pos))
    
    def mouseMoveEvent(self, evt):
        """
        Protected method to handle mouse move events.
        
        @param reference to the mouse move event (QMouseEvent)
        """
        if self.count() == 1:
            return
        
        E5WheelTabBar.mouseMoveEvent(self, evt)
        
        if Preferences.getHelp("ShowPreview"):
            # Find the tab under the mouse
            i = 0
            tabIndex = -1
            while i < self.count() and tabIndex == -1:
                if self.tabRect(i).contains(evt.pos()):
                    tabIndex = i
                i += 1
            
            # If found and not the current tab then show tab preview
            if tabIndex != -1 and \
               tabIndex != self.currentIndex() and \
               self.__currentTabPreviewIndex != tabIndex and \
               evt.buttons() == Qt.NoButton:
                self.__currentTabPreviewIndex = tabIndex
                QTimer.singleShot(200, self.__showTabPreview)
            
            # If current tab or not found then hide previous tab preview
            if tabIndex == self.currentIndex() or \
               tabIndex == -1:
                if self.__previewPopup is not None:
                    self.__previewPopup.hide()
                self.__currentTabPreviewIndex = -1
    
    def leaveEvent(self, evt):
        """
        Protected method to handle leave events.
        
        @param evt reference to the leave event (QEvent)
        """
        if Preferences.getHelp("ShowPreview"):
            # If leave tabwidget then hide previous tab preview
            if self.__previewPopup is not None:
                self.__previewPopup.hide()
            self.__currentTabPreviewIndex = -1
        
        E5WheelTabBar.leaveEvent(self, evt)
    
    def mousePressEvent(self, evt):
        """
        Protected method to handle mouse press events.
        
        @param evt reference to the mouse press event (QMouseEvent)
        """
        if Preferences.getHelp("ShowPreview"):
            if self.__previewPopup is not None:
                self.__previewPopup.hide()
            self.__currentTabPreviewIndex = -1
        
        E5WheelTabBar.mousePressEvent(self, evt)
    
    def event(self, evt):
        """
        Protected method to handle event.
        
        This event handler just handles the tooltip event and passes the
        handling of all others to the superclass.
        
        @param evt reference to the event to be handled (QEvent)
        @return flag indicating, if the event was handled (boolean)
        """
        if evt.type() == QEvent.ToolTip and \
           Preferences.getHelp("ShowPreview"):
            # suppress tool tips if we are showing previews
            evt.setAccepted(True)
            return True
        
        return E5WheelTabBar.event(self, evt)
    
    def tabRemoved(self, index):
        """
        Protected slot to handle the removal of a tab.
        
        @param index index of the removed tab (integer)
        """
        if Preferences.getHelp("ShowPreview"):
            if self.__previewPopup is not None:
                self.__previewPopup.hide()
            self.__currentTabPreviewIndex = -1