Rolled back the Windows horizontally scrolling Listbox changes because I can't seem to get it to work on Mac OS X (and keeping that code there is inefficient); removed the guarantee of horizontal scrollbars in Listbox and made that a future plan. Both the Windows and the non-working Mac OS X code is in unmigrated/hscrolllistbox.go (and the unmigrated/ folder will be renamed shortly).

futureplans.md

@@ -102,6 +102,7 @@ big dumb things:
 				- and raymond suggests GWL_USERDATA here: http://blogs.msdn.com/b/oldnewthing/archive/2005/03/03/384285.aspx
 - listboxes should have horizontal scrollbars on all platforms; this is way too hard on OS X and doesn't work; my code is in experiments/
 	- also moved the Windows code there for the sake of efficiency
+	- GTK+ works just fine though
 
 specifics:
 

listbox.go

@@ -9,7 +9,8 @@ import (
 
 // A Listbox is a vertical list of items, of which either at most one or any number of items can be selected at any given time.
 // On creation, no item is selected.
-// Listboxes have both horizontal and vertical scrollbars that are hidden when not needed.
+// Listboxes have vertical scrollbars that are hidden when not needed.
+// The presence of horizontal scrollbars is currently undefined.
 type Listbox struct {
 	// TODO Select event
 

prefsize_windows.go

@@ -150,127 +150,6 @@ func muldiv(ma int, mb int, div int) int {
 	return int(int32(r1))
 }
 
-// List Boxes do not dynamically handle horizontal scrollbars.
-// We have to manually handle this ourselves.
-// TODO make this run on the main thread when we switch to uitask taking function literals
-// TODO this is inefficient; some caching would be nice
-func recalcListboxWidth(hwnd _HWND) {
-	var size _SIZE
-
-	ret := make(chan uiret)
-	defer close(ret)
-	uitask <- &uimsg{
-		call:		_sendMessage,
-		p:		[]uintptr{
-			uintptr(hwnd),
-			uintptr(_LB_GETCOUNT),
-			uintptr(0),
-			uintptr(0),
-		},
-		ret:		ret,
-	}
-	r := <-ret
-	if r.ret == uintptr(_LB_ERR) {		// failure
-		panic(fmt.Errorf("error getting number of items for Listbox width calculations: %v", r.err))
-	}
-	n := int(r.ret)
-	uitask <- &uimsg{
-		call:		_getWindowDC,
-		p:		[]uintptr{uintptr(hwnd)},
-		ret:		ret,
-	}
-	r = <-ret
-	if r.ret == 0 {		// failure
-		panic(fmt.Errorf("error getting DC for Listbox width calculations: %v", r.err))
-	}
-	dc := _HANDLE(r.ret)
-	uitask <- &uimsg{
-		call:		_selectObject,
-		p:		[]uintptr{
-			uintptr(dc),
-			uintptr(controlFont),
-		},
-		ret:		ret,
-	}
-	r = <-ret
-	if r.ret == 0  {		// failure
-		panic(fmt.Errorf("error loading control font into device context for Listbox width calculation: %v", r.err))
-	}
-	hextent := uintptr(0)
-	for i := 0; i < n; i++ {
-		uitask <- &uimsg{
-			call:		_sendMessage,
-			p:		[]uintptr{
-				uintptr(hwnd),
-				uintptr(_LB_GETTEXTLEN),
-				uintptr(_WPARAM(i)),
-				uintptr(0),
-			},
-			ret:		ret,
-		}
-		r := <-ret
-		if r.ret == uintptr(_LB_ERR) {
-			panic("UI library internal error: LB_ERR from LB_GETTEXTLEN in what we know is a valid listbox index (came from LB_GETSELITEMS)")
-		}
-		str := make([]uint16, r.ret)
-		uitask <- &uimsg{
-			call:		_sendMessage,
-			p:		[]uintptr{
-				uintptr(hwnd),
-				uintptr(_LB_GETTEXT),
-				uintptr(_WPARAM(i)),
-				uintptr(_LPARAM(unsafe.Pointer(&str[0]))),
-			},
-			ret:		ret,
-		}
-		r = <-ret
-		if r.ret == uintptr(_LB_ERR) {
-			panic("UI library internal error: LB_ERR from LB_GETTEXT in what we know is a valid listbox index (came from LB_GETSELITEMS)")
-		}
-		// r.ret is still the length of the string; this time without the null terminator
-		uitask <- &uimsg{
-			call:		_getTextExtentPoint32,
-			p:		[]uintptr{
-				uintptr(dc),
-				uintptr(unsafe.Pointer(&str[0])),
-				r.ret,
-				uintptr(unsafe.Pointer(&size)),
-			},
-			ret:		ret,
-		}
-		r = <-ret
-		if r.ret == 0 {		// failure
-			panic(fmt.Errorf("error getting width of item %d text for Listbox width calculation: %v", i, r.err))
-		}
-		if hextent < uintptr(size.cx) {
-			hextent = uintptr(size.cx)
-		}
-	}
-	uitask <- &uimsg{
-		call:		_releaseDC,
-		p:		[]uintptr{
-			uintptr(hwnd),
-			uintptr(dc),
-		},
-		ret:		ret,
-	}
-	r = <-ret
-	if r.ret == 0 {		// failure
-		panic(fmt.Errorf("error releasing DC for Listbox width calculations: %v", r.err))
-	}
-	uitask <- &uimsg{
-		call:		_sendMessage,
-		p:		[]uintptr{
-			uintptr(hwnd),
-			uintptr(_LB_SETHORIZONTALEXTENT),
-			hextent,
-			uintptr(0),
-		},
-		ret:		ret,
-	}
-	<-ret
-}
-
 type _SIZE struct {
 	cx	int32		// originally LONG
 	cy	int32

sysdata_windows.go

@@ -87,13 +87,12 @@ var classTypes = [nctypes]*classData{
 	},
 	c_listbox:			&classData{
 		name:			"LISTBOX",
-		// TODO also _WS_HSCROLL?
 		// we don't use _LBS_STANDARD because it sorts (and has WS_BORDER; see above)
 		// _LBS_NOINTEGRALHEIGHT gives us exactly the size we want
 		// TODO say why we don't use LBS_MULTISEL (listbox docs and http://msdn.microsoft.com/en-us/library/windows/desktop/aa511485.aspx)
-		style:			_LBS_NOTIFY | _LBS_NOINTEGRALHEIGHT | _WS_HSCROLL | _WS_VSCROLL | controlstyle,
+		style:			_LBS_NOTIFY | _LBS_NOINTEGRALHEIGHT | _WS_VSCROLL | controlstyle,
 		xstyle:			_WS_EX_CLIENTEDGE | controlxstyle,
-		altStyle:			_LBS_EXTENDEDSEL | _LBS_NOTIFY | _LBS_NOINTEGRALHEIGHT | _WS_HSCROLL | _WS_VSCROLL | controlstyle,
+		altStyle:			_LBS_EXTENDEDSEL | _LBS_NOTIFY | _LBS_NOINTEGRALHEIGHT | _WS_VSCROLL | controlstyle,
 		appendMsg:		_LB_ADDSTRING,
 		insertBeforeMsg:	_LB_INSERTSTRING,
 		deleteMsg:		_LB_DELETESTRING,
@@ -355,7 +354,6 @@ func (s *sysData) append(what string) {
 	} else if r.ret == uintptr(classTypes[s.ctype].selectedIndexErr) {
 		panic(fmt.Errorf("failed to add item to combobox/listbox (last error: %v)", r.err))
 	}
-	recalcListboxWidth(s.hwnd)
 }
 
 func (s *sysData) insertBefore(what string, index int) {
@@ -377,7 +375,6 @@ func (s *sysData) insertBefore(what string, index int) {
 	} else if r.ret == uintptr(classTypes[s.ctype].selectedIndexErr) {
 		panic(fmt.Errorf("failed to add item to combobox/listbox (last error: %v)", r.err))
 	}
-	recalcListboxWidth(s.hwnd)
 }
 
 func (s *sysData) selectedIndex() int {
@@ -528,7 +525,6 @@ func (s *sysData) delete(index int) {
 	if r.ret == uintptr(classTypes[s.ctype].selectedIndexErr) {
 		panic(fmt.Errorf("failed to delete item from combobox/listbox (last error: %v)", r.err))
 	}
-	recalcListboxWidth(s.hwnd)
 }
 
 func (s *sysData) setIndeterminate() {

unmigrated/hscrolllistbox.go

@@ -0,0 +1,178 @@
+// WINDOWS (works)
+
+		style:			_LBS_NOTIFY | _LBS_NOINTEGRALHEIGHT | _WS_HSCROLL | _WS_VSCROLL | controlstyle,
+		xstyle:			_WS_EX_CLIENTEDGE | controlxstyle,
+		altStyle:			_LBS_EXTENDEDSEL | _LBS_NOTIFY | _LBS_NOINTEGRALHEIGHT | _WS_HSCROLL | _WS_VSCROLL | controlstyle,
+
+(call recalcListboxWidth() from sysData.append(), sysData.insertBefore(), and sysData.delete())
+
+// List Boxes do not dynamically handle horizontal scrollbars.
+// We have to manually handle this ourselves.
+// TODO make this run on the main thread when we switch to uitask taking function literals
+// TODO this is inefficient; some caching would be nice
+func recalcListboxWidth(hwnd _HWND) {
+	var size _SIZE
+
+	ret := make(chan uiret)
+	defer close(ret)
+	uitask <- &uimsg{
+		call:		_sendMessage,
+		p:		[]uintptr{
+			uintptr(hwnd),
+			uintptr(_LB_GETCOUNT),
+			uintptr(0),
+			uintptr(0),
+		},
+		ret:		ret,
+	}
+	r := <-ret
+	if r.ret == uintptr(_LB_ERR) {		// failure
+		panic(fmt.Errorf("error getting number of items for Listbox width calculations: %v", r.err))
+	}
+	n := int(r.ret)
+	uitask <- &uimsg{
+		call:		_getWindowDC,
+		p:		[]uintptr{uintptr(hwnd)},
+		ret:		ret,
+	}
+	r = <-ret
+	if r.ret == 0 {		// failure
+		panic(fmt.Errorf("error getting DC for Listbox width calculations: %v", r.err))
+	}
+	dc := _HANDLE(r.ret)
+	uitask <- &uimsg{
+		call:		_selectObject,
+		p:		[]uintptr{
+			uintptr(dc),
+			uintptr(controlFont),
+		},
+		ret:		ret,
+	}
+	r = <-ret
+	if r.ret == 0  {		// failure
+		panic(fmt.Errorf("error loading control font into device context for Listbox width calculation: %v", r.err))
+	}
+	hextent := uintptr(0)
+	for i := 0; i < n; i++ {
+		uitask <- &uimsg{
+			call:		_sendMessage,
+			p:		[]uintptr{
+				uintptr(hwnd),
+				uintptr(_LB_GETTEXTLEN),
+				uintptr(_WPARAM(i)),
+				uintptr(0),
+			},
+			ret:		ret,
+		}
+		r := <-ret
+		if r.ret == uintptr(_LB_ERR) {
+			panic("UI library internal error: LB_ERR from LB_GETTEXTLEN in what we know is a valid listbox index (came from LB_GETSELITEMS)")
+		}
+		str := make([]uint16, r.ret)
+		uitask <- &uimsg{
+			call:		_sendMessage,
+			p:		[]uintptr{
+				uintptr(hwnd),
+				uintptr(_LB_GETTEXT),
+				uintptr(_WPARAM(i)),
+				uintptr(_LPARAM(unsafe.Pointer(&str[0]))),
+			},
+			ret:		ret,
+		}
+		r = <-ret
+		if r.ret == uintptr(_LB_ERR) {
+			panic("UI library internal error: LB_ERR from LB_GETTEXT in what we know is a valid listbox index (came from LB_GETSELITEMS)")
+		}
+		// r.ret is still the length of the string; this time without the null terminator
+		uitask <- &uimsg{
+			call:		_getTextExtentPoint32,
+			p:		[]uintptr{
+				uintptr(dc),
+				uintptr(unsafe.Pointer(&str[0])),
+				r.ret,
+				uintptr(unsafe.Pointer(&size)),
+			},
+			ret:		ret,
+		}
+		r = <-ret
+		if r.ret == 0 {		// failure
+			panic(fmt.Errorf("error getting width of item %d text for Listbox width calculation: %v", i, r.err))
+		}
+		if hextent < uintptr(size.cx) {
+			hextent = uintptr(size.cx)
+		}
+	}
+	uitask <- &uimsg{
+		call:		_releaseDC,
+		p:		[]uintptr{
+			uintptr(hwnd),
+			uintptr(dc),
+		},
+		ret:		ret,
+	}
+	r = <-ret
+	if r.ret == 0 {		// failure
+		panic(fmt.Errorf("error releasing DC for Listbox width calculations: %v", r.err))
+	}
+	uitask <- &uimsg{
+		call:		_sendMessage,
+		p:		[]uintptr{
+			uintptr(hwnd),
+			uintptr(_LB_SETHORIZONTALEXTENT),
+			hextent,
+			uintptr(0),
+		},
+		ret:		ret,
+	}
+	<-ret
+}
+
+// DARWIN (does not work)
+
+// NSTableView is actually in a NSScrollView so we have to get it out first
+// NSTableView and NSTableColumn both provide sizeToFit methods, but they don't do what we want (NSTableView's sizes to fit the parent; NSTableColumn's sizes to fit the column header)
+// We have to get the width manually; see also http://stackoverflow.com/questions/4674163/nstablecolumn-size-to-fit-contents
+// We can use the NSTableView sizeToFit to get the height, though.
+// TODO this is inefficient!
+// TODO move this to listbox_darwin.go
+var (
+	_dataCellForRow = sel_getUid("dataCellForRow:")
+	_cellSize = sel_getUid("cellSize")
+	_setMinWidth = sel_getUid("setMinWidth:")
+	_setWidth = sel_getUid("setWidth:")
+)
+
+func listboxPrefSize(control C.id) (width int, height int) {
+	var maxwidth C.int64_t
+
+	listbox := listboxInScrollView(control)
+	_, height = controlPrefSize(listbox)
+	column := listboxTableColumn(listbox)
+	n := C.objc_msgSend_intret_noargs(listbox, _numberOfRows)
+	for i := C.intptr_t(0); i < n; i++ {
+		cell := C.objc_msgSend_int(column, _dataCellForRow, i)
+		csize := C.objc_msgSend_stret_size_noargs(cell, _cellSize)
+		if maxwidth < csize.width {
+			maxwidth = csize.width
+		}
+	}
+	// and in order for horizontal scrolling to work, we need to set the column width to this
+	C.objc_msgSend_cgfloat(column, _setMinWidth, C.double(maxwidth))
+	C.objc_msgSend_cgfloat(column, _setWidth, C.double(maxwidth))
+	return int(maxwidth), height
+}
+
+func (s *sysData) setRect(x int, y int, width int, height int, winheight int) error {
+	// 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
+	C.objc_msgSend_rect(s.id, _setFrame,
+		C.int64_t(x), C.int64_t((winheight - y) - height), C.int64_t(width), C.int64_t(height))
+	// TODO having this here is a hack; split it into a separate function in listbox_darwin.go
+	// the NSTableView:NSTableColumn ratio is what determines horizontal scrolling; see http://stackoverflow.com/questions/7050497/enable-scrolling-for-nstableview
+	if s.ctype == c_listbox {
+		listbox := listboxInScrollView(s.id)
+		C.objc_msgSend_rect(listbox, _setFrame,
+			0, 0, C.int64_t(width), C.int64_t(height))
+	}
+	return nil
+}