mupp_plot: set its own macOS Dock icon and match musrview's icon style.

TGCocoa::SetIconPixmap()/SetClassHints() are no-ops on macOS, so the xpm
mupp_plot set on its TRootCanvas only ever applied on X11 - the Dock/window
icon stayed the generic ROOT one on macOS. Use the same Cocoa helper
(PMacDockIcon.mm's SetMacDockIcon()) already used by musrview/musrFT/musrt0
to set the Dock icon from a compiled-in PNG.

The new icon's tile shape and background were measured off
src/classes/icons/musrview-512.png and matched: a rounded-square tile with
~22% corner radius and a vertical light-to-medium blue gradient background,
instead of the previous plain white tile with a gray border.

Also:
- compile PMacDockIcon.mm into mupp_plot on Darwin and link Cocoa, mirroring
  src/classes/CMakeLists.txt
- fix MUSRFIT_XDG_DATA_DIR -> MUSRFIT_XDG_DATADIR in the Linux install rules
  (the former is not a defined variable, so install() was resolving to
  absolute paths at the filesystem root)
- install a 512x512 icon on Linux too (hicolor/512x512/apps), matching
  musrview, and list it in the rpm spec

Done for both the Qt6 and Qt5 plotter.

ChangeLog

@@ -83,8 +83,8 @@ PMusrCanvas, the TCanvas based front end musrview used so far, has been removed
 together with its dictionary.
 
 musrFT, musrt0 and mupp_plot show their own window/dock icon instead of the
-generic ROOT one. On Linux, matching .desktop files and icons are installed to
-MUSRFIT_XDG_DATA_DIR.
+generic ROOT one (on macOS set via Cocoa). On Linux, matching .desktop files and
+icons are installed to MUSRFIT_XDG_DATA_DIR.
 
 Release of V1.12.1, 2026/08/25
 ==============================

cmake/musrfit-root6.spec.in

@@ -102,6 +102,7 @@ rm -rf $RPM_BUILD_ROOT
 %{_datadir}/icons/hicolor/48x48/apps/musrt0.png
 %{_datadir}/applications/mupp_plot.desktop
 %{_datadir}/icons/hicolor/48x48/apps/mupp_plot.png
+%{_datadir}/icons/hicolor/512x512/apps/mupp_plot.png
 %_prefix/share/musrfit
 
 

src/musredit_qt5/mupp/plotter/CMakeLists.txt

@@ -63,7 +63,12 @@ set(DICT
 )
 
 #--- define executable --------------------------------------------------------
-add_executable(mupp_plot ${SOURCE} ${DICT})
+#--- on macOS the Dock icon cannot be set through ROOT, hence the Cocoa helper
+#--- shared with musrview/musrFT/musrt0 is compiled in as well ----------------
+add_executable(mupp_plot
+  ${SOURCE} ${DICT}
+  $<$<PLATFORM_ID:Darwin>:${CMAKE_SOURCE_DIR}/src/classes/PMacDockIcon.mm>
+)
 
 #--- add all needed include directories ---------------------------------------
 target_include_directories(mupp_plot
@@ -73,10 +78,14 @@ target_include_directories(mupp_plot
     ${CMAKE_CURRENT_BINARY_DIR}/..
     ${CMAKE_CURRENT_SOURCE_DIR}
     ${CMAKE_CURRENT_SOURCE_DIR}/..
+    $<$<PLATFORM_ID:Darwin>:${CMAKE_SOURCE_DIR}/src/include>
 )
 
 #--- define all to be linked libs ---------------------------------------------
 target_link_libraries(mupp_plot ${ROOT_LIBRARIES})
+if (APPLE)
+  target_link_libraries(mupp_plot "-framework Cocoa")
+endif (APPLE)
 
 #--- install ------------------------------------------------------------------
 if (APPLE)
@@ -96,15 +105,20 @@ if (UNIX AND NOT APPLE)
   )
   install(
     FILES ${CMAKE_CURRENT_BINARY_DIR}/mupp_plot.desktop
-    DESTINATION ${MUSRFIT_XDG_DATA_DIR}/applications
+    DESTINATION ${MUSRFIT_XDG_DATADIR}/applications
   )
   install(
     FILES ${CMAKE_CURRENT_SOURCE_DIR}/icons/mupp_plot.png
-    DESTINATION ${MUSRFIT_XDG_DATA_DIR}/icons/hicolor/48x48/apps
+    DESTINATION ${MUSRFIT_XDG_DATADIR}/icons/hicolor/48x48/apps
+  )
+  install(
+    FILES ${CMAKE_CURRENT_SOURCE_DIR}/icons/mupp_plot-512.png
+    DESTINATION ${MUSRFIT_XDG_DATADIR}/icons/hicolor/512x512/apps
+    RENAME mupp_plot.png
   )
   #--- a stale icon cache would hide the new icon, hence refresh an existing one
   install(CODE "
-    set(icon_dir \"\$ENV{DESTDIR}${MUSRFIT_XDG_DATA_DIR}/icons/hicolor\")
+    set(icon_dir \"\$ENV{DESTDIR}${MUSRFIT_XDG_DATADIR}/icons/hicolor\")
     find_program(GTK_UPDATE_ICON_CACHE gtk-update-icon-cache)
     if (GTK_UPDATE_ICON_CACHE AND EXISTS \"\${icon_dir}/icon-theme.cache\")
       execute_process(COMMAND \${GTK_UPDATE_ICON_CACHE} -q -t -f \"\${icon_dir}\")

src/musredit_qt5/mupp/plotter/PMuppCanvas.cpp

@@ -45,6 +45,10 @@
 #include "PMuppCanvas.h"
 
 #include "icons/mupp_plot_icon.xpm"
+#ifdef __APPLE__
+#include "PMacDockIcon.h"
+#include "icons/mupp_plot_icon_png.h"
+#endif
 
 static const char *gFiletypes[] = { "Data files", "*.dat",
                                     "All files",  "*",
@@ -247,6 +251,11 @@ void PMuppCanvas::InitMuppCanvas(const Char_t *title, Int_t wtopx, Int_t wtopy,
   // replace the generic ROOT window icon; the class hint lets the desktop match mupp_plot.desktop
   fImp->SetIconPixmap(const_cast<char**>(mupp_plot_icon_xpm));
   fImp->SetClassHints("mupp_plot", "mupp_plot");
+#ifdef __APPLE__
+  // on macOS, TGCocoa::SetIconPixmap()/SetClassHints() above are no-ops: the Dock icon
+  // is process-wide and must be set via NSApplication instead
+  SetMacDockIcon(mupp_plot_icon_png, mupp_plot_icon_png_len);
+#endif
   fImp->Connect("CloseWindow()", "PMuppCanvas", this, "WindowClosed()");
   fBar = fImp->GetMenuBar();
   fPopupMain = fBar->AddPopup("&Mupp");

src/musredit_qt6/mupp/plotter/CMakeLists.txt

@@ -63,7 +63,12 @@ set(DICT
 )
 
 #--- define executable --------------------------------------------------------
-add_executable(mupp_plot ${SOURCE} ${DICT})
+#--- on macOS the Dock icon cannot be set through ROOT, hence the Cocoa helper
+#--- shared with musrview/musrFT/musrt0 is compiled in as well ----------------
+add_executable(mupp_plot
+  ${SOURCE} ${DICT}
+  $<$<PLATFORM_ID:Darwin>:${CMAKE_SOURCE_DIR}/src/classes/PMacDockIcon.mm>
+)
 
 #--- add all needed include directories ---------------------------------------
 target_include_directories(mupp_plot
@@ -73,10 +78,14 @@ target_include_directories(mupp_plot
     ${CMAKE_CURRENT_BINARY_DIR}/..
     ${CMAKE_CURRENT_SOURCE_DIR}
     ${CMAKE_CURRENT_SOURCE_DIR}/..
+    $<$<PLATFORM_ID:Darwin>:${CMAKE_SOURCE_DIR}/src/include>
 )
 
 #--- define all to be linked libs ---------------------------------------------
 target_link_libraries(mupp_plot ${ROOT_LIBRARIES})
+if (APPLE)
+  target_link_libraries(mupp_plot "-framework Cocoa")
+endif (APPLE)
 
 #--- install ------------------------------------------------------------------
 if (APPLE)
@@ -96,15 +105,20 @@ if (UNIX AND NOT APPLE)
   )
   install(
     FILES ${CMAKE_CURRENT_BINARY_DIR}/mupp_plot.desktop
-    DESTINATION ${MUSRFIT_XDG_DATA_DIR}/applications
+    DESTINATION ${MUSRFIT_XDG_DATADIR}/applications
   )
   install(
     FILES ${CMAKE_CURRENT_SOURCE_DIR}/icons/mupp_plot.png
-    DESTINATION ${MUSRFIT_XDG_DATA_DIR}/icons/hicolor/48x48/apps
+    DESTINATION ${MUSRFIT_XDG_DATADIR}/icons/hicolor/48x48/apps
+  )
+  install(
+    FILES ${CMAKE_CURRENT_SOURCE_DIR}/icons/mupp_plot-512.png
+    DESTINATION ${MUSRFIT_XDG_DATADIR}/icons/hicolor/512x512/apps
+    RENAME mupp_plot.png
   )
   #--- a stale icon cache would hide the new icon, hence refresh an existing one
   install(CODE "
-    set(icon_dir \"\$ENV{DESTDIR}${MUSRFIT_XDG_DATA_DIR}/icons/hicolor\")
+    set(icon_dir \"\$ENV{DESTDIR}${MUSRFIT_XDG_DATADIR}/icons/hicolor\")
     find_program(GTK_UPDATE_ICON_CACHE gtk-update-icon-cache)
     if (GTK_UPDATE_ICON_CACHE AND EXISTS \"\${icon_dir}/icon-theme.cache\")
       execute_process(COMMAND \${GTK_UPDATE_ICON_CACHE} -q -t -f \"\${icon_dir}\")

src/musredit_qt6/mupp/plotter/PMuppCanvas.cpp

@@ -68,6 +68,10 @@
 #include "PMuppCanvas.h"
 
 #include "icons/mupp_plot_icon.xpm"
+#ifdef __APPLE__
+#include "PMacDockIcon.h"
+#include "icons/mupp_plot_icon_png.h"
+#endif
 
 static const char *gFiletypes[] = { "Data files", "*.dat",
                                     "All files",  "*",
@@ -278,6 +282,11 @@ void PMuppCanvas::InitMuppCanvas(const Char_t *title, Int_t wtopx, Int_t wtopy,
   // replace the generic ROOT window icon; the class hint lets the desktop match mupp_plot.desktop
   fImp->SetIconPixmap(const_cast<char**>(mupp_plot_icon_xpm));
   fImp->SetClassHints("mupp_plot", "mupp_plot");
+#ifdef __APPLE__
+  // on macOS, TGCocoa::SetIconPixmap()/SetClassHints() above are no-ops: the Dock icon
+  // is process-wide and must be set via NSApplication instead
+  SetMacDockIcon(mupp_plot_icon_png, mupp_plot_icon_png_len);
+#endif
   fImp->Connect("CloseWindow()", "PMuppCanvas", this, "WindowClosed()");
   fBar = fImp->GetMenuBar();
   fPopupMain = fBar->AddPopup("&Mupp");