More Windows sizing framework code: merged together the MulDiv() instances into wrapper functions and added the basic text length storage into controlbase.

redo/basicctrls_windows.go

@@ -173,7 +173,7 @@ const (
 
 func (l *label) labelcommitResize(c *allocation, d *sizing) {
 	if !l.standalone {
-		yoff := int(C.MulDiv(C.int(labelYOffset), C.int(d.baseY), 8))
+		yoff := fromdlgunitsY(labelYOffset, d)
 		c.y += yoff
 		c.height -= yoff
 	}

redo/control_windows.go

@@ -9,6 +9,7 @@ type controlbase struct {
 	*controldefs
 	hwnd	C.HWND
 	parent	C.HWND		// for Tab and Group
+	textlen	C.LONG
 }
 
 type controlParent struct {
@@ -50,5 +51,7 @@ func (c *controlbase) text() string {
 }
 
 func (c *controlbase) setText(text string) {
-	C.setWindowText(c.hwnd, toUTF16(text))
+	t := toUTF16(text)
+	C.setWindowText(c.hwnd, t)
+	c.textlen = C.controlTextLength(c.hwnd, t)
 }

redo/sizing_windows.go

@@ -9,13 +9,25 @@ type sizing struct {
 	sizingbase
 
 	// for size calculations
-	baseX	int
+	baseX	C.int
-	baseY	int
+	baseY	C.int
 
 	// for the actual resizing
 	// possibly the HDWP
 }
 
+// note on MulDiv():
+// div will not be 0 in the usages below
+// we also ignore overflow; that isn't likely to happen for our use case anytime soon
+
+func fromdlgunitsX(du int, d *sizing) int {
+	return int(C.MulDiv(C.int(du), d.baseX, 4))
+}
+
+func fromdlgunitsY(du int, d *sizing) int {
+	return int(C.MulDiv(C.int(du), d.baseY, 8))
+}
+
 const (
 	marginDialogUnits = 7
 	paddingDialogUnits = 4
@@ -24,14 +36,14 @@ const (
 func (c *container) beginResize() (d *sizing) {
 	d = new(sizing)
 
-	d.baseX = int(C.baseX)
+	d.baseX = C.baseX
-	d.baseY = int(C.baseY)
+	d.baseY = C.baseY
 
 	if spaced {
-		d.xmargin = int(C.MulDiv(marginDialogUnits, C.int(d.baseX), 4))
+		d.xmargin = fromdlgunitsX(marginDialogUnits, d)
-		d.ymargin = int(C.MulDiv(marginDialogUnits, C.int(d.baseY), 8))
+		d.ymargin = fromdlgunitsY(marginDialogUnits, d)
-		d.xpadding = int(C.MulDiv(paddingDialogUnits, C.int(d.baseX), 4))
+		d.xpadding = fromdlgunitsX(paddingDialogUnits, d)
-		d.ypadding = int(C.MulDiv(paddingDialogUnits, C.int(d.baseY), 8))
+		d.ypadding = fromdlgunitsY(paddingDialogUnits, d)
 	}
 
 	return d
@@ -140,12 +152,8 @@ var stdDlgSizes = [nctypes]dlgunits{
 		width = defaultWidth
 	}
 	height = stdDlgSizes[s.ctype].height
-	width = int(C.MulDiv(C.int(width), C.int(d.baseX), 4))		// equivalent to right of rect
+	width = fromdlgunitsX(width, d)		// equivalent to right of rect
-	height = int(C.MulDiv(C.int(height), C.int(d.baseY), 8))		// equivalent to bottom of rect
+	height = fromdlguntisY(height, d)		// equivalent to bottom of rect
 */
 //	return width, height
 //}
-
-// note on MulDiv():
-// div will not be 0 in the usages above
-// we also ignore overflow; that isn't likely to happen for our use case anytime soon