assets: Install app icons with ECMInstallIcons (fixes #922) (#926)

assets/CMakeLists.txt

@@ -1,17 +1 @@
-if(UNIX AND NOT APPLE)
-    find_package(ECM REQUIRED NO_MODULE)
-    set(CMAKE_MODULE_PATH ${ECM_KDE_MODULE_DIR})
-    include(KDEInstallDirs)
-
-    foreach(_i 16 24 32 64 128)
-        install(FILES "freedesktop/appicons/${_i}/zeal.png"
-            DESTINATION "${KDE_INSTALL_ICONDIR}/hicolor/${_i}x${_i}/apps"
-            # TODO: Use `RENAME zeal.png` and get rid of subdirectories.
-        )
-    endforeach()
-
-    # TODO: Generate via zeal.desktop.in.
-    install(FILES "freedesktop/zeal.desktop"
-        DESTINATION ${KDE_INSTALL_APPDIR}
-    )
-endif()
+add_subdirectory(freedesktop)

assets/freedesktop/CMakeLists.txt

@@ -0,0 +1,19 @@
+if(UNIX AND NOT APPLE)
+    find_package(ECM 1.0.0 REQUIRED NO_MODULE)
+    set(CMAKE_MODULE_PATH ${ECM_MODULE_PATH})
+    include(ECMInstallIcons)
+    include(KDEInstallDirs)
+
+    ecm_install_icons(ICONS "16-apps-zeal.png"
+                            "24-apps-zeal.png"
+                            "32-apps-zeal.png"
+                            "64-apps-zeal.png"
+                            "128-apps-zeal.png"
+                      DESTINATION ${KDE_INSTALL_ICONDIR}
+    )
+
+    # TODO: Generate via zeal.desktop.in.
+    install(FILES "zeal.desktop"
+            DESTINATION ${KDE_INSTALL_APPDIR}
+    )
+endif()