Extend `SkiaLayer.disableTitleBar` to set up a custom window header (#315)

* Extend `SkiaLayer.disableTitleBar` with a parameter that contains the custom header height

The custom header height is used to align the traffic lights within the custom header

* Update PlatformOperations.kt to match the new signature

* Adjust draggable area

* Zoom on double-click

* Restore default controls when entering full screen via our own API

* Restore default controls when entering full screen

* Remove redundant code

samples/SkiaJvmSample/src/main/kotlin/SkiaJvmSample/App.kt

@@ -115,6 +115,8 @@ fun createWindow(title: String, exitOnClose: Boolean) = SwingUtilities.invokeLat
     // MANDATORY: set window preferred size before calling pack()
     window.preferredSize = Dimension(800, 600)
     window.pack()
+    skiaLayer.disableTitleBar(64f)
+    window.pack()
     skiaLayer.paint(window.graphics)
     window.isVisible = true
 }

skiko/src/jvmMain/kotlin/org/jetbrains/skiko/HardwareLayer.kt

@@ -69,6 +69,10 @@ internal open class HardwareLayer(
         get() = platformOperations.isFullscreen(this)
         set(value) = platformOperations.setFullscreen(this, value)
 
+    fun disableTitleBar(customHeaderHeight: Float) {
+        platformOperations.disableTitleBar(this, customHeaderHeight)
+    }
+
     private external fun getContentHandle(platformInfo: Long): Long
     private external fun getWindowHandle(platformInfo: Long): Long
 

skiko/src/jvmMain/kotlin/org/jetbrains/skiko/PlatformOperations.kt

@@ -7,7 +7,7 @@ import javax.swing.SwingUtilities
 internal interface PlatformOperations {
     fun isFullscreen(component: Component): Boolean
     fun setFullscreen(component: Component, value: Boolean)
-    fun disableTitleBar(platformInfo: Long)
+    fun disableTitleBar(component: Component, headerHeight: Float)
     fun orderEmojiAndSymbolsPopup()
     fun getDpiScale(component: Component): Float
 }
@@ -27,8 +27,8 @@ internal val platformOperations: PlatformOperations by lazy {
                     return component.graphicsConfiguration.defaultTransform.scaleX.toFloat()
                 }
 
-                override fun disableTitleBar(platformInfo: Long) {
-                    osxDisableTitleBar(platformInfo)
+                override fun disableTitleBar(component: Component, headerHeight: Float) {
+                    osxDisableTitleBar(component, headerHeight)
                 }
 
                 override fun orderEmojiAndSymbolsPopup() {
@@ -49,7 +49,7 @@ internal val platformOperations: PlatformOperations by lazy {
                     device.setFullScreenWindow(if (value) window else null)
                 }
 
-                override fun disableTitleBar(platformInfo: Long) {
+                override fun disableTitleBar(component: Component, headerHeight: Float) {
                 }
 
                 override fun orderEmojiAndSymbolsPopup() {
@@ -74,7 +74,7 @@ internal val platformOperations: PlatformOperations by lazy {
                     device.setFullScreenWindow(if (value) window else null)
                 }
 
-                override fun disableTitleBar(platformInfo: Long) {
+                override fun disableTitleBar(component: Component, headerHeight: Float) {
                 }
 
                 override fun orderEmojiAndSymbolsPopup() {
@@ -94,7 +94,7 @@ internal val platformOperations: PlatformOperations by lazy {
 // OSX
 external private fun osxIsFullscreenNative(component: Component): Boolean
 external private fun osxSetFullscreenNative(component: Component, value: Boolean)
-external private fun osxDisableTitleBar(platformInfo: Long)
+external private fun osxDisableTitleBar(component: Component, headerHeight: Float)
 external private fun osxOrderEmojiAndSymbolsPopup()
 
 // Linux

skiko/src/jvmMain/kotlin/org/jetbrains/skiko/SkiaLayer.jvm.kt

@@ -526,10 +526,8 @@ actual open class SkiaLayer internal constructor(
     }
 }
 
-fun SkiaLayer.disableTitleBar() {
-    backedLayer.useDrawingSurfacePlatformInfo {
-        platformOperations.disableTitleBar(it)
-    }
+fun SkiaLayer.disableTitleBar(customHeaderHeight: Float) {
+    backedLayer.disableTitleBar(customHeaderHeight)
 }
 
 fun orderEmojiAndSymbolsPopup() {

skiko/src/jvmMain/objectiveC/macos/Drawlayer.mm

@@ -8,6 +8,28 @@
 #import <Metal/Metal.h>
 #import <QuartzCore/CAMetalLayer.h>
 
+@interface WindowDragView : NSView
+@end
+
+@implementation WindowDragView
+
+- (void)mouseDown:(NSEvent *)event
+{
+    [self.window performWindowDragWithEvent:event];
+    [super mouseDown:event];
+}
+
+- (void)mouseUp:(NSEvent *)event
+{
+    if (event.clickCount == 2)
+    {
+        [self.window performZoom:nil];
+    }
+    [super mouseUp:event];
+}
+
+@end
+
 @interface LayerHandler : NSObject
 
 @property jobject canvasGlobalRef;
@@ -17,6 +39,10 @@
 @end
 
 @implementation LayerHandler
+{
+    BOOL _titlebarDisabled;
+    CGFloat _customHeaderHeight;
+}
 
 - (id) init
 {
@@ -27,19 +53,141 @@
         self.canvasGlobalRef = NULL;
         self.container = nil;
         self.window = nil;
+        _titlebarDisabled = NO;
     }
 
     return self;
 }
 
--(void) dealloc {
+-(void) dealloc
+{
     self.canvasGlobalRef = NULL;
     [self.container release];
     [self.window release];
     [super dealloc];
 }
 
-- (BOOL) isFullScreen {
+- (void) setUpCustomHeader
+{
+    NSView* themeFrame = self.window.contentView.superview;
+    NSView* titlebarContainer = [self.window standardWindowButton:NSWindowCloseButton].superview.superview;
+    NSView* titlebar = titlebarContainer.subviews[0];
+    NSView* titlebarDecoration = titlebarContainer.subviews[1];
+    NSView* titlebarVisualEffect = titlebar.subviews[0];
+    NSView* titlebarBackground = titlebar.subviews[1];
+    NSView* dragger = [[WindowDragView alloc] init];
+    [titlebarBackground addSubview:dragger];
+
+    titlebarContainer.translatesAutoresizingMaskIntoConstraints = NO;
+    titlebarDecoration.translatesAutoresizingMaskIntoConstraints = NO;
+    titlebar.translatesAutoresizingMaskIntoConstraints = NO;
+    titlebarVisualEffect.translatesAutoresizingMaskIntoConstraints = NO;
+    titlebarBackground.translatesAutoresizingMaskIntoConstraints = NO;
+    dragger.translatesAutoresizingMaskIntoConstraints = NO;
+
+    [NSLayoutConstraint activateConstraints:@[
+        [titlebarBackground.leftAnchor constraintEqualToAnchor:themeFrame.leftAnchor],
+        [titlebarBackground.rightAnchor constraintEqualToAnchor:themeFrame.rightAnchor],
+        [titlebarBackground.topAnchor constraintEqualToAnchor:themeFrame.topAnchor],
+        [titlebarBackground.heightAnchor constraintEqualToConstant:_customHeaderHeight],
+
+        [titlebarVisualEffect.leftAnchor constraintEqualToAnchor:titlebarBackground.leftAnchor],
+        [titlebarVisualEffect.rightAnchor constraintEqualToAnchor:titlebarBackground.rightAnchor],
+        [titlebarVisualEffect.topAnchor constraintEqualToAnchor:titlebarBackground.topAnchor],
+        [titlebarVisualEffect.bottomAnchor constraintEqualToAnchor:titlebarBackground.bottomAnchor],
+
+        [titlebar.leftAnchor constraintEqualToAnchor:titlebarBackground.leftAnchor],
+        [titlebar.widthAnchor constraintEqualToAnchor:titlebarBackground.widthAnchor],
+        [titlebar.topAnchor constraintEqualToAnchor:titlebarBackground.topAnchor],
+        [titlebar.heightAnchor constraintEqualToAnchor:titlebarBackground.heightAnchor],
+
+        [titlebarDecoration.leftAnchor constraintEqualToAnchor:titlebarBackground.leftAnchor],
+        [titlebarDecoration.widthAnchor constraintEqualToAnchor:titlebarBackground.widthAnchor],
+        [titlebarDecoration.topAnchor constraintEqualToAnchor:titlebarBackground.topAnchor],
+        [titlebarDecoration.heightAnchor constraintEqualToAnchor:titlebarBackground.heightAnchor],
+
+        [titlebarContainer.leftAnchor constraintEqualToAnchor:titlebar.leftAnchor],
+        [titlebarContainer.rightAnchor constraintEqualToAnchor:titlebar.rightAnchor],
+        [titlebarContainer.topAnchor constraintEqualToAnchor:titlebar.topAnchor],
+        [titlebarContainer.heightAnchor constraintEqualToAnchor:titlebar.heightAnchor],
+
+        [dragger.leftAnchor constraintEqualToAnchor:titlebarBackground.leftAnchor],
+        [dragger.rightAnchor constraintEqualToAnchor:titlebarBackground.rightAnchor],
+        [dragger.topAnchor constraintEqualToAnchor:titlebarBackground.topAnchor],
+        [dragger.bottomAnchor constraintEqualToAnchor:titlebarBackground.bottomAnchor],
+    ]];
+
+    NSView* closeButtonView = [self.window standardWindowButton:NSWindowCloseButton];
+    NSView* miniaturizeButtonView = [self.window standardWindowButton:NSWindowMiniaturizeButton];
+    NSView* zoomButtonView = [self.window standardWindowButton:NSWindowZoomButton];
+    CGFloat horizontalButtonOffset = 20.0;
+
+    NSArray* windowButtons = @[ closeButtonView, miniaturizeButtonView, zoomButtonView ];
+    for (NSUInteger i = 0; i < windowButtons.count; i++) {
+        NSView* button = [windowButtons objectAtIndex:i];
+        button.translatesAutoresizingMaskIntoConstraints = NO;
+        [NSLayoutConstraint activateConstraints:@[
+            [button.centerYAnchor constraintEqualToAnchor:titlebar.centerYAnchor],
+            [button.centerXAnchor constraintEqualToAnchor:titlebar.leftAnchor constant:(_customHeaderHeight/2.0 + (i * horizontalButtonOffset))],
+        ]];
+    }
+}
+
+- (void) resetHeader
+{
+    NSView* titlebarContainer = [self.window standardWindowButton:NSWindowCloseButton].superview.superview;
+    NSView* titlebar = titlebarContainer.subviews[0];
+    NSView* titlebarDecoration = titlebarContainer.subviews[1];
+    NSView* titlebarVisualEffect = titlebar.subviews[0];
+    NSView* titlebarBackground = titlebar.subviews[1];
+    NSView* closeButtonView = [self.window standardWindowButton:NSWindowCloseButton];
+    NSView* miniaturizeButtonView = [self.window standardWindowButton:NSWindowMiniaturizeButton];
+    NSView* zoomButtonView = [self.window standardWindowButton:NSWindowZoomButton];
+
+    NSArray* changedViews = @[titlebarContainer, titlebarDecoration, titlebar, titlebarVisualEffect, titlebarBackground, closeButtonView, miniaturizeButtonView, zoomButtonView];
+    for (NSView* changedView in changedViews)
+    {
+        [changedView removeConstraints:changedView.constraints];
+        changedView.translatesAutoresizingMaskIntoConstraints = YES;
+    }
+    NSView* dragger = titlebar.subviews[1].subviews[0];
+    [dragger removeFromSuperview];
+}
+
+- (void) setWindowControlsHidden: (BOOL) hidden
+{
+    [self.window standardWindowButton:NSWindowCloseButton].superview.hidden = hidden;
+}
+
+- (void) disableTitlebar: (CGFloat) customHeaderHeight
+{
+    _customHeaderHeight = customHeaderHeight;
+    dispatch_sync(dispatch_get_main_queue(), ^{
+        [self.window setTitlebarAppearsTransparent:YES];
+        [self.window setTitleVisibility:NSWindowTitleHidden];
+        [self.window setStyleMask:[self.window styleMask]|NSWindowStyleMaskFullSizeContentView];
+
+        if (!self.isFullScreen) {
+            [self setUpCustomHeader];
+        }
+    });
+    NSNotificationCenter* defaultCenter = [NSNotificationCenter defaultCenter];
+    NSOperationQueue* mainQueue = [NSOperationQueue mainQueue];
+    [defaultCenter addObserverForName:NSWindowWillEnterFullScreenNotification object:self.window queue:mainQueue usingBlock:^(NSNotification* notification) {
+        [self resetHeader];
+    }];
+    [defaultCenter addObserverForName:NSWindowWillExitFullScreenNotification object:self.window queue:mainQueue usingBlock:^(NSNotification* notification) {
+        [self setWindowControlsHidden:YES];
+    }];
+    [defaultCenter addObserverForName:NSWindowDidExitFullScreenNotification object:self.window queue:mainQueue usingBlock:^(NSNotification* notification) {
+        [self setUpCustomHeader];
+        [self setWindowControlsHidden:NO];
+    }];
+    _titlebarDisabled = YES;
+}
+
+- (BOOL) isFullScreen
+{
     NSUInteger masks = [self.window styleMask];
     return (masks & NSWindowStyleMaskFullScreen) != 0;
 }
@@ -177,15 +325,13 @@ JNIEXPORT jlong JNICALL Java_org_jetbrains_skiko_HardwareLayer_getContentHandle(
     return (jlong)window;
 }
 
-JNIEXPORT void JNICALL Java_org_jetbrains_skiko_PlatformOperationsKt_osxDisableTitleBar(JNIEnv *env, jobject properties, jlong platformInfoPtr)
+JNIEXPORT void JNICALL Java_org_jetbrains_skiko_PlatformOperationsKt_osxDisableTitleBar(JNIEnv *env, jobject properties, jobject component, jfloat customHeaderHeight)
 {
-    NSWindow* window = findWindow(platformInfoPtr);
-    if (window == nil) return;
-    dispatch_sync(dispatch_get_main_queue(), ^{
-        [window setTitlebarAppearsTransparent:YES];
-        [window setTitleVisibility:NSWindowTitleHidden];
-        [window setStyleMask:[window styleMask]|NSWindowStyleMaskFullSizeContentView];
-    });
+    LayerHandler *layer = findByObject(env, component);
+    if (layer != NULL)
+    {
+        [layer disableTitlebar:((CGFloat) customHeaderHeight)];
+    }
 }
 
 JNIEXPORT jint JNICALL Java_org_jetbrains_skiko_SystemTheme_1jvmKt_getCurrentSystemTheme(JNIEnv *env, jobject topLevel)