fix: cross-platform GUI fonts (v5.2 W4, #25)

"Arial" is not guaranteed on Linux and caused Tk font substitution +
misaligned dialogs. Define FONT_FAMILY (Segoe UI / Helvetica Neue / DejaVu
Sans by OS) first in config_template and route the legacy font constants
(HEADER_FONT/LABEL_FONT/FONT_SM/MD/LG/XL) through it, then swap the 31 inline
("Arial",...)/("Segoe UI",...) literals across the GUI dialogs/tooltip/utils
to (FONT_FAMILY,...). Closes #25.

GUI modules import clean; full suite green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: RFingAdam

plot_antenna/config_template.py

@@ -68,13 +68,28 @@
 SUCCESS_COLOR = "#4CAF50"
 INFO_COLOR = "#4A90E2"
 
-# GUI Fonts
-HEADER_FONT = ("Arial", 14, "bold")
-LABEL_FONT = ("Arial", 12)
-FONT_SM = ("Arial", 9)
-FONT_MD = ("Arial", 11)
-FONT_LG = ("Arial", 13)
-FONT_XL = ("Arial", 16, "bold")
+# Platform-aware font family (Linux/macOS/Windows) — defined first so every
+# font constant below uses a family that actually exists on the host. "Arial"
+# is not guaranteed on Linux and caused Tk substitution / misaligned dialogs.
+import sys as _sys
+
+if _sys.platform == "win32":
+    FONT_FAMILY = "Segoe UI"
+    _MONO_FAMILY = "Consolas"
+elif _sys.platform == "darwin":
+    FONT_FAMILY = "Helvetica Neue"
+    _MONO_FAMILY = "Menlo"
+else:  # Linux / other
+    FONT_FAMILY = "DejaVu Sans"
+    _MONO_FAMILY = "DejaVu Sans Mono"
+
+# GUI Fonts (now cross-platform via FONT_FAMILY)
+HEADER_FONT = (FONT_FAMILY, 14, "bold")
+LABEL_FONT = (FONT_FAMILY, 12)
+FONT_SM = (FONT_FAMILY, 9)
+FONT_MD = (FONT_FAMILY, 11)
+FONT_LG = (FONT_FAMILY, 13)
+FONT_XL = (FONT_FAMILY, 16, "bold")
 
 # Spacing Constants
 PAD_SM = 5
@@ -92,19 +107,7 @@
 DISABLED_FG_COLOR = "#A0A0A0"  # WCAG AA compliant (5.6:1 on #2E2E2E)
 FOCUS_BORDER_COLOR = "#5A9CF5"
 
-# Modern Fonts (platform-aware fallbacks for Linux/macOS/Windows)
-import sys as _sys
-
-if _sys.platform == "win32":
-    FONT_FAMILY = "Segoe UI"
-    _MONO_FAMILY = "Consolas"
-elif _sys.platform == "darwin":
-    FONT_FAMILY = "Helvetica Neue"
-    _MONO_FAMILY = "Menlo"
-else:  # Linux / other
-    FONT_FAMILY = "DejaVu Sans"
-    _MONO_FAMILY = "DejaVu Sans Mono"
-
+# Modern Fonts (same platform-aware family)
 HEADER_BAR_FONT = (FONT_FAMILY, 16, "bold")
 HEADER_VERSION_FONT = (FONT_FAMILY, 9)
 SECTION_HEADER_FONT = (FONT_FAMILY, 11, "bold")

plot_antenna/gui/callbacks_mixin.py

@@ -19,7 +19,7 @@
 import numpy as np
 import matplotlib.pyplot as plt
 
-from ..config import ACCENT_BLUE_COLOR, LIGHT_TEXT_COLOR
+from ..config import ACCENT_BLUE_COLOR, LIGHT_TEXT_COLOR, FONT_FAMILY
 
 from ..file_utils import (
     read_passive_file,
@@ -368,7 +368,7 @@ def display_eff_gain_table(self, results):
 
         row = 0
         for band_label, band_data in results:
-            tk.Label(result_window, text=band_label, font=("Arial", 12, "bold")).grid(
+            tk.Label(result_window, text=band_label, font=(FONT_FAMILY, 12, "bold")).grid(
                 row=row, column=0, columnspan=7, pady=5
             )
             row += 1
@@ -383,7 +383,7 @@ def display_eff_gain_table(self, results):
                 "Avg Eff(dB)",
             ]
             for col, header in enumerate(headers):
-                tk.Label(result_window, text=header, font=("Arial", 10, "bold")).grid(
+                tk.Label(result_window, text=header, font=(FONT_FAMILY, 10, "bold")).grid(
                     row=row, column=col, padx=10, pady=5
                 )
             row += 1
@@ -441,20 +441,20 @@ def display_final_summary(self, results):
         summary_window.title("Final Summary")
 
         tk.Label(
-            summary_window, text="Final Summary of All Bands", font=("Arial", 12, "bold")
+            summary_window, text="Final Summary of All Bands", font=(FONT_FAMILY, 12, "bold")
         ).grid(row=0, column=0, columnspan=len(results) + 1, pady=10)
 
-        tk.Label(summary_window, text="Parameter", font=("Arial", 10, "bold")).grid(
+        tk.Label(summary_window, text="Parameter", font=(FONT_FAMILY, 10, "bold")).grid(
             row=1, column=0, padx=10, pady=5
         )
         for col, (band_label, _) in enumerate(results, start=1):
-            tk.Label(summary_window, text=band_label, font=("Arial", 10, "bold")).grid(
+            tk.Label(summary_window, text=band_label, font=(FONT_FAMILY, 10, "bold")).grid(
                 row=1, column=col, padx=10, pady=5
             )
 
         parameters = ["Avg Eff(%)", "Avg Eff(dB)", "Min Gain(dBi)", "Max Gain(dBi)"]
         for row, param in enumerate(parameters, start=2):
-            tk.Label(summary_window, text=param, font=("Arial", 10, "bold")).grid(
+            tk.Label(summary_window, text=param, font=(FONT_FAMILY, 10, "bold")).grid(
                 row=row, column=0, sticky="w", padx=10, pady=5
             )
 

plot_antenna/gui/dialogs_mixin.py

@@ -16,6 +16,7 @@
 from typing import TYPE_CHECKING, Optional
 
 from ..config import (
+    FONT_FAMILY,
     DARK_BG_COLOR,
     LIGHT_TEXT_COLOR,
     ACCENT_BLUE_COLOR,
@@ -136,7 +137,7 @@ def show_about_dialog(self):
         name_label = tk.Label(
             header_frame,
             text="RFlect",
-            font=("Arial", 28, "bold"),
+            font=(FONT_FAMILY, 28, "bold"),
             bg=DARK_BG_COLOR,
             fg="#E63946",  # Red color similar to smith_logo.png
         )
@@ -146,7 +147,7 @@ def show_about_dialog(self):
         version_label = tk.Label(
             about_window,
             text=f"Version {self.CURRENT_VERSION}",
-            font=("Arial", 12),
+            font=(FONT_FAMILY, 12),
             bg=DARK_BG_COLOR,
             fg=LIGHT_TEXT_COLOR,
         )
@@ -156,7 +157,7 @@ def show_about_dialog(self):
         desc_label = tk.Label(
             about_window,
             text="Antenna Measurement & Analysis Tool",
-            font=("Arial", 10, "italic"),
+            font=(FONT_FAMILY, 10, "italic"),
             bg=DARK_BG_COLOR,
             fg=LIGHT_TEXT_COLOR,
         )
@@ -181,7 +182,7 @@ def show_about_dialog(self):
         credits_label = tk.Label(
             credits_frame,
             text=credits_text,
-            font=("Arial", 9),
+            font=(FONT_FAMILY, 9),
             bg=DARK_BG_COLOR,
             fg=LIGHT_TEXT_COLOR,
             justify=tk.LEFT,
@@ -192,7 +193,7 @@ def show_about_dialog(self):
         license_label = tk.Label(
             about_window,
             text="Licensed under GNU General Public License v3.0",
-            font=("Arial", 8),
+            font=(FONT_FAMILY, 8),
             bg=DARK_BG_COLOR,
             fg=LIGHT_TEXT_COLOR,
         )
@@ -987,7 +988,7 @@ def _on_outer_destroy(event):
                 text="(single freq)",
                 bg=DARK_BG_COLOR,
                 fg="#A0A0A0",
-                font=("Arial", 9),
+                font=(FONT_FAMILY, 9),
             ).grid(row=4, column=3, sticky=tk.W)
 
             # CSV file for per-frequency conducted power (batch processing)
@@ -1371,7 +1372,7 @@ def save_passive_settings():
             title = tk.Label(
                 settings_window,
                 text="VSWR/Return Loss Settings",
-                font=("Arial", 12, "bold"),
+                font=(FONT_FAMILY, 12, "bold"),
                 bg=DARK_BG_COLOR,
                 fg=LIGHT_TEXT_COLOR,
             )

plot_antenna/gui/tools_mixin.py

@@ -25,6 +25,7 @@
 import requests
 
 from ..config import (
+    FONT_FAMILY,
     ACCENT_BLUE_COLOR,
     DARK_BG_COLOR,
     LIGHT_TEXT_COLOR,
@@ -176,34 +177,42 @@ def generate_report_from_directory(self):
         report_dialog.grab_set()
 
         # Title
-        tk.Label(report_dialog, text="Report Generation", font=("Arial", 14, "bold")).pack(pady=10)
+        tk.Label(report_dialog, text="Report Generation", font=(FONT_FAMILY, 14, "bold")).pack(
+            pady=10
+        )
 
         # Report title
-        tk.Label(report_dialog, text="Report Title:", font=("Arial", 10)).pack(anchor="w", padx=20)
+        tk.Label(report_dialog, text="Report Title:", font=(FONT_FAMILY, 10)).pack(
+            anchor="w", padx=20
+        )
         title_var = tk.StringVar(value="Antenna Measurement Report")
         tk.Entry(report_dialog, textvariable=title_var, width=50).pack(padx=20, pady=5)
 
         # Project name
-        tk.Label(report_dialog, text="Project Name:", font=("Arial", 10)).pack(anchor="w", padx=20)
+        tk.Label(report_dialog, text="Project Name:", font=(FONT_FAMILY, 10)).pack(
+            anchor="w", padx=20
+        )
         project_var = tk.StringVar()
         tk.Entry(report_dialog, textvariable=project_var, width=50).pack(padx=20, pady=5)
 
         # Antenna type
         tk.Label(
-            report_dialog, text="Antenna Type (e.g., Patch, Monopole, PIFA):", font=("Arial", 10)
+            report_dialog,
+            text="Antenna Type (e.g., Patch, Monopole, PIFA):",
+            font=(FONT_FAMILY, 10),
         ).pack(anchor="w", padx=20)
         antenna_var = tk.StringVar()
         tk.Entry(report_dialog, textvariable=antenna_var, width=50).pack(padx=20, pady=5)
 
         # Frequency range
         tk.Label(
-            report_dialog, text="Frequency Range (e.g., 2.4-2.5 GHz):", font=("Arial", 10)
+            report_dialog, text="Frequency Range (e.g., 2.4-2.5 GHz):", font=(FONT_FAMILY, 10)
         ).pack(anchor="w", padx=20)
         freq_var = tk.StringVar()
         tk.Entry(report_dialog, textvariable=freq_var, width=50).pack(padx=20, pady=5)
 
         # Author
-        tk.Label(report_dialog, text="Author/Engineer:", font=("Arial", 10)).pack(
+        tk.Label(report_dialog, text="Author/Engineer:", font=(FONT_FAMILY, 10)).pack(
             anchor="w", padx=20
         )
         author_var = tk.StringVar()
@@ -872,41 +881,43 @@ def open_polarization_interactive(self):
             freq_dialog.grab_set()
 
             # Frequency selection
-            tk.Label(freq_dialog, text="Select Frequency (MHz):", font=("Arial", 11, "bold")).pack(
-                pady=10
-            )
+            tk.Label(
+                freq_dialog, text="Select Frequency (MHz):", font=(FONT_FAMILY, 11, "bold")
+            ).pack(pady=10)
             freq_var = tk.StringVar(value=str(freq_list[0]))
-            freq_listbox = tk.Listbox(freq_dialog, height=6, font=("Arial", 10))
+            freq_listbox = tk.Listbox(freq_dialog, height=6, font=(FONT_FAMILY, 10))
             for freq in freq_list:
                 freq_listbox.insert(tk.END, f"{freq} MHz")
             freq_listbox.selection_set(0)
             freq_listbox.pack(pady=5)
 
             # Plot options
-            tk.Label(freq_dialog, text="Visualization Options:", font=("Arial", 11, "bold")).pack(
-                pady=10
-            )
+            tk.Label(
+                freq_dialog, text="Visualization Options:", font=(FONT_FAMILY, 11, "bold")
+            ).pack(pady=10)
             plot_2d_var = tk.BooleanVar(value=True)
             plot_3d_var = tk.BooleanVar(value=True)
 
             tk.Checkbutton(
                 freq_dialog,
                 text="Show 2D Plots (Contour + Polar)",
                 variable=plot_2d_var,
-                font=("Arial", 10),
+                font=(FONT_FAMILY, 10),
             ).pack()
             tk.Checkbutton(
                 freq_dialog,
                 text="Show 3D Plots (Spherical)",
                 variable=plot_3d_var,
-                font=("Arial", 10),
+                font=(FONT_FAMILY, 10),
             ).pack()
 
             # Export option
-            tk.Label(freq_dialog, text="Export Options:", font=("Arial", 11, "bold")).pack(pady=10)
+            tk.Label(freq_dialog, text="Export Options:", font=(FONT_FAMILY, 11, "bold")).pack(
+                pady=10
+            )
             export_var = tk.BooleanVar(value=False)
             tk.Checkbutton(
-                freq_dialog, text="Export data to file", variable=export_var, font=("Arial", 10)
+                freq_dialog, text="Export data to file", variable=export_var, font=(FONT_FAMILY, 10)
             ).pack()
 
             # Results container
@@ -930,10 +941,10 @@ def on_cancel():
             button_frame = tk.Frame(freq_dialog)
             button_frame.pack(pady=20)
             tk.Button(
-                button_frame, text="OK", command=on_ok, width=10, font=("Arial", 10, "bold")
+                button_frame, text="OK", command=on_ok, width=10, font=(FONT_FAMILY, 10, "bold")
             ).pack(side=tk.LEFT, padx=5)
             tk.Button(
-                button_frame, text="Cancel", command=on_cancel, width=10, font=("Arial", 10)
+                button_frame, text="Cancel", command=on_cancel, width=10, font=(FONT_FAMILY, 10)
             ).pack(side=tk.LEFT, padx=5)
 
             # Wait for dialog to close

plot_antenna/gui/tooltip.py

@@ -1,6 +1,7 @@
 """Lightweight tooltip widget for Tkinter."""
 
 import tkinter as tk
+from ..config import FONT_FAMILY
 
 
 class ToolTip:
@@ -42,7 +43,7 @@ def _show(self):
             fg="#DDDDDD",
             relief=tk.SOLID,
             borderwidth=1,
-            font=("Segoe UI", 9),
+            font=(FONT_FAMILY, 9),
             padx=8,
             pady=4,
         )

plot_antenna/gui/utils.py

@@ -11,6 +11,7 @@
 from ..file_utils import parse_2port_data
 import pandas as pd
 import numpy as np
+from ..config import FONT_FAMILY
 
 
 class DualOutput:
@@ -143,15 +144,15 @@ def display_parameter_table(results, param_name, parent):
     row = 0
     for band_label, band_data in results:
         # Band label
-        tk.Label(parent, text=band_label, font=("Arial", 12, "bold")).grid(
+        tk.Label(parent, text=band_label, font=(FONT_FAMILY, 12, "bold")).grid(
             row=row, column=0, columnspan=3, pady=10
         )
         row += 1
 
         # Table headers for each band
         headers = ["File", f"Min {param_name}", f"Max {param_name}"]
         for col, header in enumerate(headers):
-            tk.Label(parent, text=header, font=("Arial", 10, "bold")).grid(
+            tk.Label(parent, text=header, font=(FONT_FAMILY, 10, "bold")).grid(
                 row=row, column=col, padx=10, pady=5
             )
         row += 1