Legge til støtte for zoom med CTRL + scroll

soitool/inline_editable_soi_view.py

@@ -30,7 +30,10 @@ from soitool.modules.module_base import qfont_with_pixel_size
 ATTACHMENT_NUMBERING_SCHEME = list(string.ascii_uppercase)
 
 # Amount to zoom on scroll
-SCROLL_ZOOM_FACTOR = 1.1
+SCROLL_ZOOM_INCREMENT = 0.1
+
+ZOOM_LEVEL_MINIMUM = 0.2
+ZOOM_LEVEL_MAXIMUM = 5
 
 
 class QGraphicsViewWithCtrlScrollListener(QGraphicsView):
@@ -293,19 +296,21 @@ class InlineEditableSOIView(QScrollArea):
         # when scrolling up
         downward_scroll = bool(event.angleDelta().y() < 1)
 
-        zoom_factor = SCROLL_ZOOM_FACTOR
+        zoom_increment = SCROLL_ZOOM_INCREMENT
         if downward_scroll:
-            zoom_factor = 1 / zoom_factor
+            zoom_increment *= -1
 
         self.zoom(
-            zoom_factor, anchor=QGraphicsView.ViewportAnchor.AnchorUnderMouse
+            zoom_increment,
+            anchor=QGraphicsView.ViewportAnchor.AnchorUnderMouse,
         )
 
         self.show_zoom_level_in_statusbar()
 
     def show_zoom_level_in_statusbar(self):
         """Show zoom level in statusbar."""
-        zoom_level_percentage_string = str(round(self.zoom_level * 100))
+        current_scale = self.get_current_scale()
+        zoom_level_percentage_string = str(round(current_scale * 100))
         message = f"Zoom: {zoom_level_percentage_string}%"
         get_main_window().statusBar().showMessage(message)
 
@@ -733,29 +738,61 @@ class InlineEditableSOIView(QScrollArea):
         timer.start(10)
 
     def zoom(
-        self, zoom_factor, anchor=QGraphicsView.ViewportAnchor.AnchorViewCenter
+        self,
+        zoom_increment,
+        anchor=QGraphicsView.ViewportAnchor.AnchorViewCenter,
     ):
         """Zoom GraphicsView by zoom_factor.
 
+        The zoom level is held within ZOOM_LEVEL_MINIMUM and
+        ZOOM_LEVEL_MAXIMUM.
+
+        Note that because of inaccuracy during floating point operations the
+        current scale is sometimes off by an insignificant fraction
+        (e.g. 0.0000000000000001)
+
         source:
         * https://stackoverflow.com/a/29026916/3545896
         * https://stackoverflow.com/a/41688654/3545896
 
         Parameters
         ----------
-        zoom_factor : float
-            > 1 to zoom in and < 1 to zoom out
+        zoom_increment : float
+            How much to increase zoom by. 1 means increase by 100%, -0.5 means
+            decrease by -50%, and so on.
         anchor : QGraphicsView.ViewportAnchor
             Anchor indicates where to aim the zoom. See the documentation for
             QGraphicsView.ViewportAnchor.
             QGraphicsView.ViewportAnchor.AnchorUnderMouse can be used to target
             the mouse.
         """
-        self.zoom_level *= zoom_factor
-        viewport_anchor = self.view.transformationAnchor()
-        self.view.setTransformationAnchor(anchor)
-        self.view.scale(zoom_factor, zoom_factor)
-        self.view.setTransformationAnchor(viewport_anchor)
+        current_scale = self.get_current_scale()
+
+        # Only zoom if we are not breaching the minimum and maximum range
+        new_scale = current_scale + zoom_increment
+        if new_scale > ZOOM_LEVEL_MINIMUM and new_scale < ZOOM_LEVEL_MAXIMUM:
+            # We need a scalar such that:
+            # current_scale * scalar = current_scale + zoom_increment
+            scalar = (current_scale + zoom_increment) / current_scale
+
+            viewport_anchor = self.view.transformationAnchor()
+            self.view.setTransformationAnchor(anchor)
+            self.view.scale(
+                scalar, scalar,
+            )
+            self.view.setTransformationAnchor(viewport_anchor)
+
+    def get_current_scale(self):
+        """Get current scale.
+
+        Returns
+        -------
+        scale : float
+            Horizontal and vertical scale. They should always be equal in our
+            case.
+        """
+        scale_x = self.view.transform().m11()
+        return scale_x
 
 
 def soi_date_string_to_user_friendly_string(date_string):