CMake: Add default launch screen storyboard for iOS apps

Bundle a default LaunchScreen.storyboard file for an iOS app and make
sure it's referenced in the generated Info.plist file.

When launching Qt examples, it ensures the app uses the whole screen
space on the device rather than just a square-ish part of it.

The storyboard file is a copy of the qmake one, which qmake adds
to the Xcode projects it generates.

A custom launch screen can be provided either by setting the
QT_IOS_LAUNCH_SCREEN variable or by setting the
QT_IOS_LAUNCH_SCREEN target property.
The value must be an absolute path to the launch screen file.

The automatic addition of the launch screen entry in the Info.plist
file can be prevented by setting the QT_NO_SET_IOS_LAUNCH_SCREEN
variable to TRUE.

The automatic bundling of the launch screen file in the application
bundle can be prevented by setting the
QT_NO_ADD_IOS_LAUNCH_SCREEN_TO_BUNDLE variable to TRUE.

The current implementation has a limitation that only one launch
screen storyboard and one iOS executable can exist within a project.

If there are multiple executables in the project, all of them will
use the launch screen that is specified last (the last
qt_add_executable call).

Because of this limitation, the API is marked as Technical Preview,
to be improved upon in the future. For now it simply serves as an
improvement to the out-of-the-box experience of iOS apps built
with CMake.

Amends 4d838dae5a821e9e5f013ba1d5a494ece1b5180e

Fixes: QTBUG-95837
Change-Id: I6b067d703d635122959a1ef17fcca713da694a86
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
(cherry picked from commit e5b3436255ce095af58608b03b913fc9bcb8e61f)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

4 files changed, 59 insertions, 3 deletions

diff --git a/cmake/QtBaseGlobalTargets.cmake b/cmake/QtBaseGlobalTargets.cmake
index 0759b9616a..c42b1f38f9 100644
--- a/cmake/QtBaseGlobalTargets.cmake
+++ b/cmake/QtBaseGlobalTargets.cmake
@@ -359,6 +359,7 @@ if(MACOS)
 elseif(IOS)
     qt_copy_or_install(FILES
         cmake/ios/MacOSXBundleInfo.plist.in
+        cmake/ios/LaunchScreen.storyboard
         DESTINATION "${__GlobalConfig_install_dir}/ios"
     )
 endif()
diff --git a/cmake/QtConfig.cmake.in b/cmake/QtConfig.cmake.in
index 21550253d6..624fd99a13 100644
--- a/cmake/QtConfig.cmake.in
+++ b/cmake/QtConfig.cmake.in
@@ -44,7 +44,8 @@ if(APPLE AND (NOT CMAKE_SYSTEM_NAME OR CMAKE_SYSTEM_NAME STREQUAL "Darwin"))
     list(APPEND CMAKE_MODULE_PATH "${_qt_import_prefix}/macos")
 elseif(APPLE AND CMAKE_SYSTEM_NAME STREQUAL "iOS")
     # Add module directory to pick up custom Info.plist template for iOS
-    list(APPEND CMAKE_MODULE_PATH "${_qt_import_prefix}/ios")
+    set(__qt_internal_cmake_ios_support_files_path "${_qt_import_prefix}/ios")
+    list(APPEND CMAKE_MODULE_PATH "${__qt_internal_cmake_ios_support_files_path}")
 endif()
 
 set(QT_ADDITIONAL_PACKAGES_PREFIX_PATH "" CACHE STRING
diff --git a/cmake/ios/LaunchScreen.storyboard b/cmake/ios/LaunchScreen.storyboard
new file mode 100644
index 0000000000..cfe5d26eba
--- /dev/null
+++ b/cmake/ios/LaunchScreen.storyboard
@@ -0,0 +1,48 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="13142" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" launchScreen="YES" useTraitCollections="YES" useSafeAreas="YES" colorMatched="YES" initialViewController="01J-lp-oVM">
+    <dependencies>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="12042"/>
+        <capability name="Constraints with non-1.0 multipliers" minToolsVersion="5.1"/>
+        <capability name="Safe area layout guides" minToolsVersion="9.0"/>
+        <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
+    </dependencies>
+    <scenes>
+        <!--View Controller-->
+        <scene sceneID="EHf-IW-A2E">
+            <objects>
+                <viewController id="01J-lp-oVM" sceneMemberID="viewController">
+                    <view key="view" contentMode="scaleToFill" id="Ze5-6b-2t3">
+                        <rect key="frame" x="0.0" y="0.0" width="375" height="667"/>
+                        <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+                        <subviews>
+                            <label opaque="NO" clipsSubviews="YES" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="" textAlignment="center" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" minimumFontSize="9" translatesAutoresizingMaskIntoConstraints="NO" id="obG-Y5-kRd">
+                                <rect key="frame" x="0.0" y="626.5" width="375" height="20.5"/>
+                                <fontDescription key="fontDescription" type="system" pointSize="17"/>
+                                <color key="textColor" red="0.0" green="0.0" blue="0.0" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+                                <nil key="highlightedColor"/>
+                            </label>
+                            <label opaque="NO" clipsSubviews="YES" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="@QT_IOS_LAUNCH_SCREEN_TEXT@" textAlignment="center" lineBreakMode="middleTruncation" baselineAdjustment="alignBaselines" minimumFontSize="18" translatesAutoresizingMaskIntoConstraints="NO" id="GJd-Yh-RWb">
+                                <rect key="frame" x="0.0" y="202" width="375" height="43"/>
+                                <fontDescription key="fontDescription" type="boldSystem" pointSize="36"/>
+                                <color key="textColor" red="0.0" green="0.0" blue="0.0" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+                                <nil key="highlightedColor"/>
+                            </label>
+                        </subviews>
+                        <color key="backgroundColor" red="1" green="1" blue="1" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+                        <constraints>
+                            <constraint firstItem="Bcu-3y-fUS" firstAttribute="centerX" secondItem="obG-Y5-kRd" secondAttribute="centerX" id="5cz-MP-9tL"/>
+                            <constraint firstItem="Bcu-3y-fUS" firstAttribute="centerX" secondItem="GJd-Yh-RWb" secondAttribute="centerX" id="Q3B-4B-g5h"/>
+                            <constraint firstItem="obG-Y5-kRd" firstAttribute="leading" secondItem="Bcu-3y-fUS" secondAttribute="leading" constant="20" symbolic="YES" id="SfN-ll-jLj"/>
+                            <constraint firstAttribute="bottom" secondItem="obG-Y5-kRd" secondAttribute="bottom" constant="20" id="Y44-ml-fuU"/>
+                            <constraint firstItem="GJd-Yh-RWb" firstAttribute="centerY" secondItem="Ze5-6b-2t3" secondAttribute="bottom" multiplier="1/3" constant="1" id="moa-c2-u7t"/>
+                            <constraint firstItem="GJd-Yh-RWb" firstAttribute="leading" secondItem="Bcu-3y-fUS" secondAttribute="leading" constant="20" symbolic="YES" id="x7j-FC-K8j"/>
+                        </constraints>
+                        <viewLayoutGuide key="safeArea" id="Bcu-3y-fUS"/>
+                    </view>
+                </viewController>
+                <placeholder placeholderIdentifier="IBFirstResponder" id="iYj-Kq-Ea1" userLabel="First Responder" sceneMemberID="firstResponder"/>
+            </objects>
+            <point key="canvasLocation" x="53" y="375"/>
+        </scene>
+    </scenes>
+</document>
diff --git a/cmake/ios/MacOSXBundleInfo.plist.in b/cmake/ios/MacOSXBundleInfo.plist.in
index 616abe9f10..5b15af1302 100644
--- a/cmake/ios/MacOSXBundleInfo.plist.in
+++ b/cmake/ios/MacOSXBundleInfo.plist.in
@@ -28,10 +28,16 @@
 	<key>CFBundleDevelopmentRegion</key>
 	<string>English</string>
 
-        <key>LSRequiresIPhoneOS</key>
+	<key>LSRequiresIPhoneOS</key>
 	<true/>
 
-        <key>UISupportedInterfaceOrientations</key>
+	<key>NOTE</key>
+	<string>This file was generated by Qt's default CMake support.</string>
+
+	<key>UILaunchStoryboardName</key>
+	<string>${QT_INTERNAL_IOS_LAUNCH_SCREEN_PLIST_ENTRY}</string>
+
+	<key>UISupportedInterfaceOrientations</key>
 	<array>
 		<string>UIInterfaceOrientationPortrait</string>
 		<string>UIInterfaceOrientationPortraitUpsideDown</string>