swipemap.py

# -*- coding: utf-8 -*-
"""
/***************************************************************************
Name                 : MapSwipe tool
Description          : Plugin for swipe active layer
Date                 : October, 2015
copyright            : (C) 2015 by Hirofumi Hayashi and Luiz Motta
email                : hayashi@apptec.co.jp and motta.luiz@gmail.com

 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/
"""

__author__ = 'Luiz Motta'
__date__ = '2015-10-14'
__copyright__ = '(C) 2018, Luiz Motta'
__revision__ = '$Format:%H$'


from qgis.PyQt.QtCore import QRect, QLine, Qt
from qgis.PyQt.QtGui import QColor, QImage

from qgis.core import QgsMapRendererParallelJob, QgsMapSettings
from qgis.gui import QgsMapCanvasItem

class SwipeMap(QgsMapCanvasItem):
  def __init__(self, canvas):
    super().__init__( canvas )
    self.length = 0
    self.isVertical = True
    self.setZValue(-9.0)
    self.flg = False
    self.layers = []
    self.canvas = canvas
    self.image = None
      
  def clear(self):
    del self.layers[:]
    self.length = -1

  def setLayers(self, layers):
     # Call clear() before
    for item in layers:
      self.layers.append( item) 

  def setIsVertical(self, isVertical):
    self.isVertical = isVertical 

  def setLength(self, x, y):
    y = int(self.boundingRect().height() - y)
    self.length = int(x) if self.isVertical else int(y)
    self.update()
      
  def paint(self, painter, *args): # NEED *args for   WINDOWS!
    if len( self.layers ) == 0 or self.length == -1:
      return
  
    if self.isVertical:
      h = int(self.boundingRect().height() - 2)
      w = int(self.length)
      line = QLine( w-1,0,w-1,h-1 )
    
    else:
      h = int(self.boundingRect().height() - self.length)
      w = int(self.boundingRect().width() - 2)
      line = QLine( 0,h-1,w-1,h-1 )
  
    image = self.image.copy( 0, 0, w, h )
    painter.drawImage( QRect( 0,0,w,h ), image )
    painter.drawLine( line )

  # It is a slot, the decorator 'pyqtSlot' fail because QgsMapCanvasItem not is QObject
  def setMap(self):
    def finished():
      # https://qgis.org/api/2.18/qgsmapcanvasmap_8cpp_source.html
      # setContent()
      image = job.renderedImage()
      if bool( self.canvas.property('retro') ):
        image = image.scaled( image.width() / 3, image.height() / 3 )
        image = image.convertToFormat( QImage.Format_Indexed8, Qt.OrderedDither | Qt.OrderedAlphaDither )
      self.image = image

    if len( self.layers ) == 0:
      return

    settings = QgsMapSettings( self.canvas.mapSettings() )
    settings.setLayers( self.layers )
    settings.setBackgroundColor( QColor( Qt.transparent ) )
    
    self.setRect( self.canvas.extent() )
    job = QgsMapRendererParallelJob( settings ) 
    job.start()
    job.finished.connect( finished) 
    job.waitForFinished()