QTabWidget documentMode not working correctly on Mac

This feature was implemented in Carbon and was never ported to Cocoa.
The major problem is the fact that Cocoa draws a line under the titlebar,
regardless of what we say. The only way to avoid drawing that line is
by adding a native toolbar and ask it not to draw its baseline. If there
is not toolbar, as it happens in this case, there is no way to prevent
that line from being drawn. So instead we paint over that line and hope
for the best.

Task-number: QTBUG-8159
Reviewed-by: Richard Moe Gustavsen

1 files changed, 54 insertions, 0 deletions

diff --git a/src/gui/kernel/qcocoasharedwindowmethods_mac_p.h b/src/gui/kernel/qcocoasharedwindowmethods_mac_p.h
index e94d247..8652816 100644
--- a/src/gui/kernel/qcocoasharedwindowmethods_mac_p.h
+++ b/src/gui/kernel/qcocoasharedwindowmethods_mac_p.h
@@ -363,3 +363,57 @@ QT_END_NAMESPACE
     }
     [super displayIfNeeded];
 }
+
+// This is a hack and it should be removed once we find the real cause for
+// the painting problems.
+// We have a static variable that signals if we have been called before or not.
+static bool firstDrawingInvocation = true;
+
+// The method below exists only as a workaround to draw/not draw the baseline
+// in the title bar. This is to support unifiedToolbar look.
+
+// This method is very special. To begin with, it is a
+// method that will get called only if we enable documentMode.
+// Furthermore, it won't get called as a normal method, we swap
+// this method with the normal implementation of drawRect in
+// _NSThemeFrame. When this method is active, its mission is to
+// first call the original drawRect implementation so the widget
+// gets proper painting. After that, it needs to detect if there
+// is a toolbar or not, in order to decide how to handle the unified
+// look. The distinction is important since the presence and
+// visibility of a toolbar change the way we enter into unified mode.
+// When there is a toolbar and that toolbar is visible, the problem
+// is as simple as to tell the toolbar not to draw its baseline.
+// However when there is not toolbar or the toolbar is not visible,
+// we need to draw a line on top of the baseline, because the baseline
+// in that case will belong to the title. For this case we need to draw
+// a line on top of the baseline.
+// As usual, there is a special case. When we first are called, we might
+// need to repaint ourselves one more time. We only need that if we
+// didn't get the activation, i.e. when we are launched via the command
+// line. And this only if the toolbar is visible from the beginning,
+// so we have a special flag that signals if we need to repaint or not.
+- (void)drawRectSpecial:(NSRect)rect
+{
+    // Call the original drawing method.
+    [self drawRectOriginal:rect];
+    NSWindow *window = [self window];
+    NSToolbar *toolbar = [window toolbar];
+    if(!toolbar) {
+        // There is no toolbar, we have to draw a line on top of the line drawn by Cocoa.
+        macDrawRectOnTop((void *)window);
+    } else {
+        if([toolbar isVisible]) {
+            // We tell Cocoa to avoid drawing the line at the end.
+            if(firstDrawingInvocation) {
+                firstDrawingInvocation = false;
+                macSyncDrawingOnFirstInvocation((void *)window);
+            } else
+                [toolbar setShowsBaselineSeparator:NO];
+        } else {
+            // There is a toolbar but it is not visible so
+            // we have to draw a line on top of the line drawn by Cocoa.
+            macDrawRectOnTop((void *)window);
+        }
+    }
+}