Added the necessary work to make new regular Labels work on the other platforms.

area.go

@@ -346,7 +346,7 @@ func (a *Area) setRect(x int, y int, width int, height int, rr *[]resizerequest)
 	})
 }
 
-func (a *Area) preferredSize() (width int, height int) {
+func (a *Area) preferredSize() (width int, height int, yoff int) {
 	return a.sysData.preferredSize()
 }
 

button.go

@@ -75,6 +75,6 @@ func (b *Button) setRect(x int, y int, width int, height int, rr *[]resizereques
 	})
 }
 
-func (b *Button) preferredSize() (width int, height int) {
+func (b *Button) preferredSize() (width int, height int, yoff int) {
 	return b.sysData.preferredSize()
 }

checkbox.go

@@ -80,6 +80,6 @@ func (c *Checkbox) setRect(x int, y int, width int, height int, rr *[]resizerequ
 	})
 }
 
-func (c *Checkbox) preferredSize() (width int, height int) {
+func (c *Checkbox) preferredSize() (width int, height int, yoff int) {
 	return c.sysData.preferredSize()
 }

combobox.go

@@ -157,6 +157,6 @@ func (c *Combobox) setRect(x int, y int, width int, height int, rr *[]resizerequ
 	})
 }
 
-func (c *Combobox) preferredSize() (width int, height int) {
+func (c *Combobox) preferredSize() (width int, height int, yoff int) {
 	return c.sysData.preferredSize()
 }

control.go

@@ -6,5 +6,5 @@ package ui
 type Control interface {
 	make(window *sysData) error
 	setRect(x int, y int, width int, height int, rr *[]resizerequest)
-	preferredSize() (width int, height int)
+	preferredSize() (width int, height int, yoff int)
 }

grid.go

@@ -21,7 +21,7 @@ type Grid struct {
 	controls                 [][]Control
 	filling                  [][]bool
 	stretchyrow, stretchycol int
-	widths, heights          [][]int // caches to avoid reallocating each time
+	widths, heights, yoff          [][]int // caches to avoid reallocating each time
 	rowheights, colwidths    []int
 }
 
@@ -42,12 +42,14 @@ func NewGrid(nPerRow int, controls ...Control) *Grid {
 	cf := make([][]bool, nRows)
 	cw := make([][]int, nRows)
 	ch := make([][]int, nRows)
+	cyoff := make([][]int, nRows)
 	i := 0
 	for row := 0; row < nRows; row++ {
 		cc[row] = make([]Control, nPerRow)
 		cf[row] = make([]bool, nPerRow)
 		cw[row] = make([]int, nPerRow)
 		ch[row] = make([]int, nPerRow)
+		cyoff[row] = make([]int, nPerRow)
 		for x := 0; x < nPerRow; x++ {
 			cc[row][x] = controls[i]
 			i++
@@ -60,6 +62,7 @@ func NewGrid(nPerRow int, controls ...Control) *Grid {
 		stretchycol: -1,
 		widths:      cw,
 		heights:     ch,
+		yoff:		cyoff,
 		rowheights:  make([]int, nRows),
 		colwidths:   make([]int, nPerRow),
 	}
@@ -142,11 +145,12 @@ func (g *Grid) setRect(x int, y int, width int, height int, rr *[]resizerequest)
 	// 2) get preferred sizes; compute row/column sizes
 	for row, xcol := range g.controls {
 		for col, c := range xcol {
-			w, h := c.preferredSize()
+			w, h, yoff := c.preferredSize()
 			g.widths[row][col] = w
 			g.heights[row][col] = h
 			g.rowheights[row] = max(g.rowheights[row], h)
 			g.colwidths[col] = max(g.colwidths[col], w)
+			g.yoff[row][col] = yoff
 		}
 	}
 	// 3) handle the stretchy control
@@ -174,7 +178,7 @@ func (g *Grid) setRect(x int, y int, width int, height int, rr *[]resizerequest)
 				w = g.colwidths[col]
 				h = g.rowheights[row]
 			}
-			c.setRect(x, y, w, h, rr)
+			c.setRect(x, y + g.yoff[row][col], w, h - g.yoff[row][col], rr)
 			x += g.colwidths[col]
 		}
 		x = startx
@@ -184,7 +188,7 @@ func (g *Grid) setRect(x int, y int, width int, height int, rr *[]resizerequest)
 }
 
 // filling and stretchy are ignored for preferred size calculation
-func (g *Grid) preferredSize() (width int, height int) {
+func (g *Grid) preferredSize() (width int, height int, yoff int) {
 	max := func(a int, b int) int {
 		if a > b {
 			return a
@@ -202,7 +206,8 @@ func (g *Grid) preferredSize() (width int, height int) {
 	// 2) get preferred sizes; compute row/column sizes
 	for row, xcol := range g.controls {
 		for col, c := range xcol {
-			w, h := c.preferredSize()
+			// ignore yoff for preferred size calculations
+			w, h, _ := c.preferredSize()
 			g.widths[row][col] = w
 			g.heights[row][col] = h
 			g.rowheights[row] = max(g.rowheights[row], h)
@@ -216,5 +221,7 @@ func (g *Grid) preferredSize() (width int, height int) {
 	for _, h := range g.rowheights {
 		height += h
 	}
-	return width, height
+
+	// yoff is always zero for grids
+	return width, height, 0
 }

label.go

@@ -84,6 +84,6 @@ func (l *Label) setRect(x int, y int, width int, height int, rr *[]resizerequest
 	})
 }
 
-func (l *Label) preferredSize() (width int, height int) {
+func (l *Label) preferredSize() (width int, height int, yoff int) {
 	return l.sysData.preferredSize()
 }

lineedit.go

@@ -78,6 +78,6 @@ func (l *LineEdit) setRect(x int, y int, width int, height int, rr *[]resizerequ
 	})
 }
 
-func (l *LineEdit) preferredSize() (width int, height int) {
+func (l *LineEdit) preferredSize() (width int, height int, yoff int) {
 	return l.sysData.preferredSize()
 }

listbox.go

@@ -160,6 +160,6 @@ func (l *Listbox) setRect(x int, y int, width int, height int, rr *[]resizereque
 	})
 }
 
-func (l *Listbox) preferredSize() (width int, height int) {
+func (l *Listbox) preferredSize() (width int, height int, yoff int) {
 	return l.sysData.preferredSize()
 }

prefsize_unix.go

@@ -12,11 +12,13 @@ package ui
 // There is a warning about height-for-width controls, but in my tests this isn't an issue.
 // For Areas, we manually save the Area size and use that, just to be safe.
 
-func (s *sysData) preferredSize() (width int, height int) {
+// We don't need to worry about y-offset because label alignment is "vertically center", which GtkLabel does for us.
+
+func (s *sysData) preferredSize() (width int, height int, yoff int) {
 	if s.ctype == c_area {
-		return s.areawidth, s.areaheight
+		return s.areawidth, s.areaheight, 0
 	}
 
 	_, _, width, height = gtk_widget_get_preferred_size(s.widget)
-	return width, height
+	return width, height, 0
 }

progressbar.go

@@ -66,6 +66,6 @@ func (p *ProgressBar) setRect(x int, y int, width int, height int, rr *[]resizer
 	})
 }
 
-func (p *ProgressBar) preferredSize() (width int, height int) {
+func (p *ProgressBar) preferredSize() (width int, height int, yoff int) {
 	return p.sysData.preferredSize()
 }

stack.go

@@ -25,7 +25,7 @@ type Stack struct {
 	orientation   orientation
 	controls      []Control
 	stretchy      []bool
-	width, height []int // caches to avoid reallocating these each time
+	width, height, yoff []int // caches to avoid reallocating these each time
 }
 
 func newStack(o orientation, controls ...Control) *Stack {
@@ -35,6 +35,7 @@ func newStack(o orientation, controls ...Control) *Stack {
 		stretchy:    make([]bool, len(controls)),
 		width:       make([]int, len(controls)),
 		height:      make([]int, len(controls)),
+		yoff:		make([]int, len(controls)),
 	}
 }
 
@@ -92,7 +93,8 @@ func (s *Stack) setRect(x int, y int, width int, height int, rr *[]resizerequest
 			nStretchy++
 			continue
 		}
-		w, h := c.preferredSize()
+		w, h, yoff := c.preferredSize()
+		s.yoff[i] = yoff
 		if s.orientation == horizontal { // all controls have same height
 			s.width[i] = w
 			s.height[i] = height
@@ -120,7 +122,7 @@ func (s *Stack) setRect(x int, y int, width int, height int, rr *[]resizerequest
 	}
 	// 3) now actually place controls
 	for i, c := range s.controls {
-		c.setRect(x, y, s.width[i], s.height[i], rr)
+		c.setRect(x, y + s.yoff[i], s.width[i], s.height[i] - s.yoff[i], rr)
 		if s.orientation == horizontal {
 			x += s.width[i]
 		} else {
@@ -131,7 +133,7 @@ func (s *Stack) setRect(x int, y int, width int, height int, rr *[]resizerequest
 }
 
 // The preferred size of a Stack is the sum of the preferred sizes of non-stretchy controls + (the number of stretchy controls * the largest preferred size among all stretchy controls).
-func (s *Stack) preferredSize() (width int, height int) {
+func (s *Stack) preferredSize() (width int, height int, yoff int) {
 	max := func(a int, b int) int {
 		if a > b {
 			return a
@@ -143,10 +145,11 @@ func (s *Stack) preferredSize() (width int, height int) {
 	var maxswid, maxsht int
 
 	if len(s.controls) == 0 { // no controls, so return emptiness
-		return 0, 0
+		return 0, 0, 0
 	}
 	for i, c := range s.controls {
-		w, h := c.preferredSize()
+		// ignore yoff for preferred size calculations
+		w, h, _ := c.preferredSize()
 		if s.stretchy[i] {
 			nStretchy++
 			maxswid = max(maxswid, w)
@@ -169,6 +172,9 @@ func (s *Stack) preferredSize() (width int, height int) {
 	} else {
 		height += nStretchy * maxsht
 	}
+
+	// yoff is always zero for stacks
+	yoff = 0
 	return
 }
 

sysdata.go

@@ -36,7 +36,7 @@ var _xSysData interface {
 	selectedTexts() []string
 	setWindowSize(int, int) error
 	delete(int)
-	preferredSize() (int, int)
+	preferredSize() (int, int, int)
 	setProgress(int)
 	len() int
 	setAreaSize(int, int)