From 5d6672069ea1cbceb62104f66c127e4e3c23e4a4 Mon Sep 17 00:00:00 2001
From: wyzula-jan <jan.wyzula@psi.ch>
Date: Wed, 19 Jun 2024 11:43:44 +0200
Subject: [PATCH] fix(plot_base): font size is set with setScale which is
 scaling the whole legend window

---
 bec_widgets/widgets/figure/plots/plot_base.py | 14 ++++----------
 tests/unit_tests/test_waveform1d.py           | 13 ++++++-------
 2 files changed, 10 insertions(+), 17 deletions(-)

diff --git a/bec_widgets/widgets/figure/plots/plot_base.py b/bec_widgets/widgets/figure/plots/plot_base.py
index a646f184..abd35787 100644
--- a/bec_widgets/widgets/figure/plots/plot_base.py
+++ b/bec_widgets/widgets/figure/plots/plot_base.py
@@ -139,16 +139,10 @@ class BECPlotBase(BECConnector, pg.GraphicsLayout):
         if self.config.axis.legend_label_size or size:
             if size:
                 self.config.axis.legend_label_size = size
-            style = {
-                "color": self.get_text_color(),
-                "size": f"{self.config.axis.legend_label_size}pt",
-            }
-        else:
-            style = {}
-        for item in self.plot_item.legend.items:
-            for single_item in item:
-                if isinstance(single_item, pg.graphicsItems.LabelItem.LabelItem):
-                    single_item.setText(single_item.text, **style)
+                scale = (
+                    size / 9
+                )  # 9 is the default font size of the legend, so we always scale it against 9
+                self.plot_item.legend.setScale(scale)
 
     def get_text_color(self):
         return "#FFF" if self.figure.config.theme == "dark" else "#000"
diff --git a/tests/unit_tests/test_waveform1d.py b/tests/unit_tests/test_waveform1d.py
index 32b93cc5..6a461b16 100644
--- a/tests/unit_tests/test_waveform1d.py
+++ b/tests/unit_tests/test_waveform1d.py
@@ -201,13 +201,12 @@ def test_change_legend_font_size(bec_figure):
     plot = bec_figure.add_plot()
 
     w1 = plot.add_curve_scan(x_name="samx", y_name="bpm4i")
-    my_func = plot.plot_item.legend.items[0][1]
-    with mock.patch.object(my_func, "setText") as mock_set_text:
-        plot.set_legend_label_size(16)
-        assert plot.config.axis.legend_label_size == 16
-        assert mock_set_text.call_count == 1
-        style = {"color": plot.get_text_color(), "size": "16pt"}
-        assert mock_set_text.call_args == mock.call(my_func.text, **style)
+    my_func = plot.plot_item.legend
+    with mock.patch.object(my_func, "setScale") as mock_set_scale:
+        plot.set_legend_label_size(18)
+        assert plot.config.axis.legend_label_size == 18
+        assert mock_set_scale.call_count == 1
+        assert mock_set_scale.call_args == mock.call(2)
 
 
 def test_remove_curve(bec_figure):