add aspect ratio (#587)

Co-authored-by: dl1com <1631996+dl1com@users.noreply.github.com>

src/main/python/ayab/ayab.py

@@ -112,8 +112,7 @@ def __activate_menu(self):
         self.menu.ui.action_load_AYAB_firmware.triggered.connect(
             self.flash.open)
         self.menu.ui.action_cancel.triggered.connect(self.engine.cancel)
-        self.menu.ui.action_set_preferences.triggered.connect(
-            self.prefs.open_dialog)
+        self.menu.ui.action_set_preferences.triggered.connect(self.__set_prefs)
         self.menu.ui.action_about.triggered.connect(self.about.show)
         # get names of image actions from Transform methods
         transforms = filter(lambda x: x[0] != "_", Transform.__dict__.keys())
@@ -122,6 +121,10 @@ def __activate_menu(self):
             slot = getattr(self.scene.ayabimage, t)
             action.triggered.connect(slot)
 
+    def __set_prefs(self):
+        self.prefs.open_dialog()
+        self.scene.refresh()
+
     def __quit(self):
         logging.debug("Quitting")
         QCoreApplication.instance().quit()

src/main/python/ayab/preferences.py

@@ -34,6 +34,7 @@
 from .engine.mode import Mode
 from .machine import Machine
 from .language import Language
+from .scene import AspectRatio
 
 
 def str2bool(qvariant):
@@ -62,6 +63,7 @@ class Preferences(SignalSender):
         'default_infinite_repeat': bool,
         'default_alignment': Alignment,
         'default_knit_side_image': bool,
+        'aspect_ratio': AspectRatio,
         # 'default_continuous_reporting': bool,
         'quiet_mode': bool,
         'disable_hardware_beep': bool,

src/main/python/ayab/scene.py

@@ -19,6 +19,7 @@
 #    https://github.com/AllYarnsAreBeautiful/ayab-desktop
 
 import logging
+from enum import Enum
 
 from PyQt5.QtCore import QRect
 from PyQt5.QtGui import QImage, QPixmap, QBrush, QColor
@@ -29,6 +30,15 @@
 from .machine import Machine
 
 
+class AspectRatio(Enum):
+    DEFAULT = 0
+    FAIRISLE = 1
+
+    def add_items(box):
+        box.addItem("1:1")
+        box.addItem("4:5")
+
+
 class Scene(QGraphicsView):
     """Graphics scene object for UI.
 
@@ -112,7 +122,7 @@ def refresh(self):
                 self.LIMIT_BAR_WIDTH))
 
         self.resetTransform()
-        self.scale(self.zoom, self.zoom)
+        self.scale(self.zoom, self.zoom * (1.0 - 0.2 * self.__prefs.value("aspect_ratio")))
         self.setScene(qscene)
 
     @property