1 files changed, 144 insertions, 0 deletions
diff --git a/src/main/python/utils/canvas.py b/src/main/python/utils/canvas.py
new file mode 100644
index 0000000..2332087
--- /dev/null
+++ b/src/main/python/utils/canvas.py
@@ -0,0 +1,144 @@
+import pickle
+
+from PyQt5.QtCore import Qt
+from PyQt5.QtGui import QBrush, QPalette
+from PyQt5.QtWidgets import (QFileDialog, QApplication, QHBoxLayout, QMenu,
+                             QTabWidget, QWidget, QSpacerItem, QStyle)
+
+from . import dialogs
+from .graphics import customView, customScene
+from .data import paperSizes, ppiList, sheetDimensionList
+
+class canvas(QWidget):
+    """
+    Defines the work area for a single sheet. Contains a QGraphicScene along with necessary properties
+    for context menu and dialogs.
+    """
+        
+    def __init__(self, parent=None, size= 'A4', ppi= '72'):
+        super(canvas, self).__init__(parent)
+        
+        #Store values for the canvas dimensions for ease of access, these are here just to be
+        # manipulated by the setters and getters
+        self._ppi = ppi
+        self._canvasSize = size
+        # self.setFixedSize(parent.size())
+        #Create area for the graphic items to be placed, this is just here right now for the future
+        # when we will draw items on this, this might be changed if QGraphicScene is subclassed.
+        
+        #set layout and background color
+        self.painter = customScene()        
+        self.painter.setBackgroundBrush(QBrush(Qt.white)) #set white background
+        
+        self.view = customView(self.painter, self) #create a viewport for the canvas board
+        
+        self.layout = QHBoxLayout(self) #create the layout of the canvas, the canvas could just subclass QGView instead
+        self.layout.addWidget(self.view, alignment=Qt.AlignCenter)
+        self.layout.setContentsMargins(0, 0, 0, 0)
+        self.setLayout(self.layout)
+        
+        #set initial paper size for the scene
+        self.painter.setSceneRect(0, 0, *paperSizes[self.canvasSize][self.ppi])
+        
+        #set pointers to necessary parents for ease of reference
+        self.parentMdiArea = self.parent().parentWidget().parentWidget().parentWidget().parentWidget()
+        self.parentFileWindow = self.parent().parentWidget().parentWidget()
+
+    def resizeView(self, w, h):
+        #helper function to resize canvas
+        self.painter.setSceneRect(0, 0, w, h)
+
+    def adjustView(self):
+        #utitily to adjust current diagram view
+        width, height = self.dimensions
+        frameWidth = self.view.frameWidth()
+        #update view size
+        self.view.setSceneRect(0, 0, width - frameWidth*2, height)
+        
+        # use the available mdi area, also add padding
+        prect = self.parentMdiArea.rect()
+        width = width + 20
+        height = height + 60
+
+        # add scrollbar size to width and height if they are visible, avoids clipping
+        if self.view.verticalScrollBar().isVisible():
+            width += self.style().pixelMetric(QStyle.PM_ScrollBarExtent)
+        if self.view.horizontalScrollBar().isVisible():
+            height += self.style().pixelMetric(QStyle.PM_ScrollBarExtent)
+        
+        #if view is visible use half of available width
+        factor = 2 if self.parentFileWindow.sideViewTab is not None else 1
+        #use minimum width required to fit the view
+        width = min((prect.width() - 40)//factor, width) 
+        height = min(prect.height() - 80, height)
+        #set view dims
+        self.view.setFixedWidth(width)
+        self.view.setFixedHeight(height)
+        
+    def resizeEvent(self, event):
+        #overloaded function to also view size on window update
+        self.adjustView()
+   
+    def setCanvasSize(self, size):
+        """
+        extended setter for dialog box
+        """
+        self.canvasSize = size
+    
+    def setCanvasPPI(self, ppi):
+        """
+        extended setter for dialog box
+        """
+        self.ppi = ppi
+    
+    @property
+    def dimensions(self):
+        #returns the dimension of the current scene
+        return self.painter.sceneRect().width(), self.painter.sceneRect().height()
+    @property
+    def items(self):
+        # generator to filter out certain items
+        for i in self.painter.items():
+            yield i
+    
+    @property
+    def canvasSize(self):
+        return self._canvasSize
+    @property
+    def ppi(self):
+        return self._ppi
+    
+    @canvasSize.setter
+    def canvasSize(self, size):
+        self._canvasSize = size
+        if self.painter:
+            self.resizeView(*paperSizes[self.canvasSize][self.ppi])
+
+    @ppi.setter
+    def ppi(self, ppi):
+        self._ppi = ppi
+        if self.painter:
+            self.resizeView(*paperSizes[self.canvasSize][self.ppi])
+        
+    #following 2 methods are defined for correct pickling of the scene. may be changed to json or xml later so as
+    # to not have a binary file.
+    def __getstate__(self) -> dict:
+        return {
+            "_classname_": self.__class__.__name__,
+            "ppi": self._ppi,
+            "canvasSize": self._canvasSize,
+            "ObjectName": self.objectName(),
+            "items": [i.__getState__() for i in self.painter.items()]
+        }
+    
+    def __setstate__(self, dict):
+        self.__init__()
+        self._ppi = dict['ppi']
+        self._canvasSize = dict['canvasSize']
+        self.setObjectName(dict['ObjectName'])
+        for item in dict['items']:
+            graphic = getattr(graphics, dict['_classname_'])
+            graphic.__setstate__(item)
+            self.painter.addItem(graphic)
+
+ 
+\ No newline at end of file