GUI: Scale to fit, fix for unstable size due to scroll bars

gui/src/aaregui/widgets/camera_image.py

@@ -1,3 +1,4 @@
+import math
 from enum import Enum
 
 from PySide6.QtCore import Qt, QTimer, QRect, QPoint, Signal, Slot, QPointF
@@ -171,7 +172,7 @@ class SampleCameraImageLabel(QGraphicsView):
 
         menu = QMenu(self)
 
-        scale_action = menu.addAction("Scale to width")
+        scale_action = menu.addAction("Scale to fit")
         scale_action.setCheckable(True)
         scale_action.setChecked(self.__autoscale)
 
@@ -247,20 +248,28 @@ class SampleCameraImageLabel(QGraphicsView):
     def __scaling(self):
         if not self.__autoscale:
             self.setTransform(QTransform())
+            self.setVerticalScrollBarPolicy(Qt.ScrollBarPolicy.ScrollBarAsNeeded)
+            self.setHorizontalScrollBarPolicy(Qt.ScrollBarPolicy.ScrollBarAsNeeded)
             return
 
         if self.pixmap_item is None:
             return
 
-        if self.pixmap_item.boundingRect().width() == 0:
+        self.setVerticalScrollBarPolicy(Qt.ScrollBarPolicy.ScrollBarAlwaysOff)
+        self.setHorizontalScrollBarPolicy(Qt.ScrollBarPolicy.ScrollBarAlwaysOff)
+
+        if self.pixmap_item.boundingRect().width() == 0 or self.pixmap_item.boundingRect().height() == 0:
             ratio = 1.0
         else:
-            ratio = self.viewport().size().width() / self.pixmap_item.boundingRect().width()
+            ratio_w = self.viewport().size().width() / self.pixmap_item.boundingRect().width()
+            ratio_h = self.viewport().size().height() / self.pixmap_item.boundingRect().height()
+            ratio = min(ratio_w, ratio_h)
 
-        if ratio < 0.2:
-            ratio = 0.2
+        if ratio < 0.1:
+            ratio = 0.1
 
         if ratio >= 1.0:
+            # Don't enable scaling when gain in ratio is < 5% (to avoid back-and-forth
             self.setTransform(QTransform())
         else:
             matrix = QTransform()