Finished proposed new sizing system.

newsizing

@@ -1,14 +1,25 @@
 type sysSizeData struct {
+	// for size calculations
+	// all platforms
+	margin	int	// windows: calculated
+	spacing	int	// gtk+, cocoa: constants
 	// windows
 	baseX	int
 	baseY	int
-	// possibly also the HDWP
 	// gtk, mac os x: nothing
+
+	// for the actual resizing
+	// windows
+	// possibly also the HDWP
+	// gtk
+	shouldVAlignTop	bool
+	// mac os x
+	// neighbor control alignment rect/baseline info
 }
 
 func (s *sysData) beginResize() *sysSizeData {
-	// windows: get baseX/baseY for window
-	// gtk, mac: return nothing
+	// windows: get baseX/baseY for window and compute margin and spacing
+	// gtk, mac: return zero
 }
 
 func (s *sysData) endResize(d *sysSizeData) {
@@ -27,35 +38,85 @@ type allocation struct {
 func (s *sysData) translateAllocationCoords(allocations []*allocation, winwidth, winheight int) {
 	// windows, gtk: nothing
 	// mac
-	for _, allocation := range allocations {
+	for _, a := range allocations {
 		// winheight - y because (0,0) is the bottom-left corner of the window and not the top-left corner
 		// (winheight - y) - height because (x, y) is the bottom-left corner of the control and not the top-left
-		allocation.y = (winheight - allocation.y) - allocation.height
+		a.y = (winheight - a.y) - a.height
 	}
 }
 
 func (s *sysData) resizeWindow(width, height int) {
-	d := s.startResize()
-	allocations := s.resize(0, 0, width, height, d)
+	d := s.beginResize()
+	allocations := s.allocate(0, 0, width, height, d)
 	s.translateAllocationCoords(allocations, width, height)
 	for _, c := range s.allocations {
 		c.this.doResize(c, d)
 	}
-	s.finishResize(d)
+	s.endResize(d)
 }
 
-main widget sizing function
-	get preferred size of all subwidgets
-		windows: uses dialog base units
-	produce map of which controls are next to which controls
-	properly space controls
-		windows: uses dialog base units
-	return list of size allocations back to window sizer
+// setSize() becomes allocate()
+// each allocate on a non-layout control should just return a one-element slice
+// each doResize and getAuxResizeInfo on a control should just defer to sysData
+type Control interface {
+	// ...
+	allocate(x int, y int, width int, height int, d *sysSizeData) []*allocation
+	preferredSize(d *sysSizeData) (width, height int)
+	doResize(c *allocation, d *sysSizeData)
+	getAuxResizeInfo(d *sysSizeData)
+}
 
-each doResize on a control should just defer to sysData.doResize()
+// vertical stack: no concept of neighbor, but not too hard to add a vertical neighbor
+// horizontal stack:
+	var current *allocation
+	// ...
+	as := s.controls[i].allocate(...)
+	if current != nil {
+		current.neighbor = as[0].self
+	}
+	current = as[0]
+	// append all of as
+// grid:
+	// same as above, except current is set to nil on each new row
+	// adding a vertical neighbor would require storing an extra list
 
-each widget adjustment
-	mac: neighboring control baselines are aligned for labels
-	gtk: vertical alignment of text changed to top if neighboring control is multi-line
-		TODO - should it be center-aligned vertically or not
-	windows: none
+// windows
+func (s *sysData) doResize(c *allocation, d *sysSizeData) {
+	if s.ctype == c_label {
+		// add additional offset of 4 dialog units
+	}
+	// resize
+}
+func (s *sysData) getAuxResizeInfo(d *sysSizeData) {
+	// do nothing
+}
+
+// gtk+
+func (s *sysData) doResize(c *allocation, d *sysSizeData) {
+	if s.ctype == c_label && !s.alternate && c.neighbor != nil {
+		c.neighbor.getAuxResizeInfo(d)
+		if d.shouldVAlignTop {
+			// TODO should it be center-aligned to the first line or not
+			gtk_misc_set_align(s.widget, 0, 0)
+		} else {
+			gtk_misc_set_align(s.widget, 0, 0.5)
+		}
+	}
+	// resize
+}
+func (s *sysData) getAuxResizeInfo(d *sysSizeData) {
+	d.shouldVAlignTop = (s.ctype == c_listbox) || (s.ctype == c_area)
+}
+
+// cocoa
+func (s *sysData) doResize(c *allocation, d *sysSizeData) {
+	if s.ctype == c_label && !s.alternate && c.neighbor != nil {
+		c.neighbor.getAuxResizeInfo(d)
+		// get this control's alignment rect and baseline
+		// align
+	}
+	// resize
+}
+func (s *sysData) getAuxResizeInfo(d *sysSizeData) {
+	// get this control's alignment rect and baseline
+}