BBox: Always offset the top border by the same amount

...so that the top border of BBox's with no labels, BBox's with
text labels, and BBox's with BControl labels will all line up.

headers/os/interface/Box.h

@@ -63,6 +63,7 @@ class BBox : public BView {
 		virtual	void		ResizeToPreferred();
 		virtual	void		GetPreferredSize(float* _width, float* _height);
 		virtual	void		MakeFocus(bool focused = true);
+		virtual	void		SetFont(const BFont* font, uint32 mask = B_FONT_ALL);
 		virtual	status_t	GetSupportedSuites(BMessage* message);
 
 		virtual	status_t	Perform(perform_code d, void* arg);
@@ -96,6 +97,7 @@ class BBox : public BView {
 		border_style		fStyle;
 		BView*				fLabelView;
 		LayoutData*			fLayoutData;
+		float				fLabelHeight;
 };
 
 #endif	// _BOX_H

src/kits/interface/Box.cpp

@@ -158,12 +158,7 @@ BBox::Border() const
 float
 BBox::TopBorderOffset()
 {
-	_ValidateLayoutData();
+	return fLabelHeight / 2;
-
-	if (fLabel != NULL || fLabelView != NULL)
-		return fLayoutData->label_box.Height() / 2;
-
-	return 0;
 }
 
 
@@ -446,6 +441,18 @@ BBox::MakeFocus(bool focused)
 }
 
 
+void
+BBox::SetFont(const BFont* font, uint32 mask)
+{
+	BView::SetFont(font, mask);
+
+	// recalculate the label height based on the new font
+	font_height fontHeight;
+	GetFontHeight(&fontHeight);
+	fLabelHeight = ceilf(fontHeight.ascent + fontHeight.descent) + 1;
+}
+
+
 status_t
 BBox::GetSupportedSuites(BMessage* message)
 {
@@ -635,6 +642,11 @@ BBox::_InitObject(BMessage* archive)
 
 	if (flags != 0)
 		SetFont(&font, flags);
+	else {
+		font_height fontHeight;
+		GetFontHeight(&fontHeight);
+		fLabelHeight = ceilf(fontHeight.ascent + fontHeight.descent) + 1;
+	}
 
 	if (archive != NULL) {
 		const char* string;
@@ -801,8 +813,9 @@ BBox::_ValidateLayoutData()
 		return;
 
 	// compute the label box, width and height
-	bool label = true;
+	bool hasLabel = true;
-	float labelHeight = 0;	// height of the label (pixel count)
+	float labelHeight = 0;
+		// height of the label (pixel count)
 	if (fLabel) {
 		// leave 6 pixels of the frame, and have a gap of 4 pixels between
 		// the frame and the text on either side
@@ -810,14 +823,15 @@ BBox::_ValidateLayoutData()
 		GetFontHeight(&fontHeight);
 		fLayoutData->label_box.Set(6.0f, 0, 14.0f + StringWidth(fLabel),
 			ceilf(fontHeight.ascent));
-		labelHeight = ceilf(fontHeight.ascent + fontHeight.descent) + 1;
+		labelHeight = fLabelHeight;
 	} else if (fLabelView) {
 		// the label view is placed at (0, 10) at its preferred size
 		BSize size = fLabelView->PreferredSize();
 		fLayoutData->label_box.Set(10, 0, 10 + size.width, size.height);
 		labelHeight = size.height + 1;
 	} else {
-		label = false;
+		labelHeight = fLabelHeight;
+		hasLabel = false;
 	}
 
 	// border
@@ -834,8 +848,8 @@ BBox::_ValidateLayoutData()
 			break;
 	}
 
-	// if there's a label, the top inset will be dictated by the label
+	// Grow the top inset by the label height
-	if (label && labelHeight > fLayoutData->insets.top)
+	if (labelHeight > fLayoutData->insets.top)
 		fLayoutData->insets.top = labelHeight;
 
 	// total number of pixel the border adds
@@ -843,11 +857,8 @@ BBox::_ValidateLayoutData()
 	float addHeight = fLayoutData->insets.top + fLayoutData->insets.bottom;
 
 	// compute the minimal width induced by the label
-	float minWidth;
+	float minWidth = !hasLabel ? addWidth - 1
-	if (label)
+		: fLayoutData->label_box.right + fLayoutData->insets.right;
-		minWidth = fLayoutData->label_box.right + fLayoutData->insets.right;
-	else
-		minWidth = addWidth - 1;
 
 	// finally consider the child constraints, if we shall support layout
 	BView* child = _Child();