#18 ViewArea nå GraphicsScene + zoom

WIP

soitool/main_window.py

 """Hovedvinduet."""
 import sys
 import os
-from PySide2.QtWidgets import QTabWidget, QWidget, QMainWindow, \
-    QApplication, QHBoxLayout, QVBoxLayout, QPushButton, QTreeWidget, QLabel
+from PySide2.QtCore import QRectF, QPoint, QTimer
+from PySide2.QtWidgets import QTabWidget, QWidget, QMainWindow, QApplication, \
+    QHBoxLayout, QVBoxLayout, QPushButton, QTreeWidget, QGraphicsScene, \
+    QGraphicsView
 from PySide2 import QtGui
 
 
@@ -72,12 +74,66 @@ class MainWidget(QWidget):
 class ViewArea(QWidget):
     """Widget som kan byttes ut med view, edit etc."""
 
+    A4_RATIO = 1.414
+    HEIGHT = 1700
+    WIDTH = HEIGHT * A4_RATIO
+    PADDING = 100
+    CONTENT_WIDTH = WIDTH - PADDING * 2
+    CONTENT_HEIGHT = HEIGHT - PADDING * 2
+    HEADER_HEIGHT = 200
+
     def __init__(self):
         super().__init__()
-        test = QLabel("Test")
-        layout = QHBoxLayout()
-        layout.addWidget(test)
-        self.setLayout(layout)
+
+        self.layout = QHBoxLayout()
+
+        self.scene = QGraphicsScene()
+        self.scene.setSceneRect(QRectF(0, 0, self.WIDTH, self.HEIGHT))
+        self.scene.addRect(0, 0, self.WIDTH, self.HEIGHT)
+        self.scene.addRect(self.PADDING, self.PADDING, self.CONTENT_WIDTH, self.CONTENT_HEIGHT)
+        self.scene.addRect(self.PADDING, self.PADDING, self.CONTENT_WIDTH, self.HEADER_HEIGHT)
+
+        self.view = QGraphicsView(self.scene)
+        self.view.scale(0.50, 0.50)
+
+        self.layout.addWidget(self.view)
+        self.setLayout(self.layout)
+
+        self.launch_auto_zoom()
+
+    def launch_auto_zoom(self):
+        """Zoom in a regular interval.
+
+        Used to demonstrate zooming only, should be removed once the project matures.
+        """
+        def do_on_timeout():
+            self.zoom(1 / 1.00005)
+
+        timer = QTimer(self)
+        timer.timeout.connect(do_on_timeout)
+        timer.start(10)
+
+    def zoom(self, zoom_factor):
+        """Zoom GraphicsView by zoom_factor.
+
+        source: https://stackoverflow.com/a/29026916/3545896
+
+        Parameters
+        ----------
+        zoom_factor : float
+            > 1 to zoom in and < 1 to zoom out
+        """
+        # Set Anchors
+        self.view.setTransformationAnchor(QGraphicsView.NoAnchor)
+        self.view.setResizeAnchor(QGraphicsView.NoAnchor)
+
+        # Zoom
+        self.view.scale(zoom_factor, zoom_factor)
+
+        pos_old = self.view.mapToScene(QPoint(self.WIDTH / 2, self.HEIGHT / 2))
+        pos_new = self.view.mapToScene(self.WIDTH / 2, self.HEIGHT / 2)
+        delta = pos_new - pos_old
+        self.view.translate(delta.x(), delta.y())
 
 
 app = QApplication([])