Started the actual new container framework.

newctrl/container.go

@@ -0,0 +1,29 @@
+// 25 june 2014
+
+package ui
+
+type sizingbase struct {
+	xpadding      int
+	ypadding      int
+}
+
+// The container type, which is defined per-platform, is an internal Control that is only used to house other Controls from the underlying UI toolkit's point of view
+
+// set to true to apply spacing to all windows
+var spaced bool = false
+
+/* TODO
+func (c *container) resize(x, y, width, height int) {
+	if c.child == nil { // no children; nothing to do
+		return
+	}
+	d := c.beginResize()
+	allocations := c.child.allocate(x+d.xmargin, y+d.ymargintop,
+		width-(2*d.xmargin), height-d.ymargintop-d.ymarginbottom, d)
+	c.translateAllocationCoords(allocations, width, height)
+	// move in reverse so as to approximate right->left order so neighbors make sense
+	for i := len(allocations) - 1; i >= 0; i-- {
+		allocations[i].this.commitResize(allocations[i], d)
+	}
+}
+*/

newctrl/container_windows.go

@@ -0,0 +1,128 @@
+// 4 august 2014
+
+package ui
+
+import (
+	"fmt"
+	"syscall"
+	"unsafe"
+)
+
+// #include "winapi_windows.h"
+import "C"
+
+type container struct {
+	*controlSingleHWND
+}
+
+type sizing struct {
+	sizingbase
+
+	// for size calculations
+	baseX           C.int
+	baseY           C.int
+	internalLeading C.LONG // for Label; see Label.commitResize() for details
+
+	// for the actual resizing
+	// possibly the HDWP
+}
+
+func makeContainerWindowClass() error {
+	var errmsg *C.char
+
+	err := C.makeContainerWindowClass(&errmsg)
+	if err != 0 || errmsg != nil {
+		return fmt.Errorf("%s: %v", C.GoString(errmsg), syscall.Errno(err))
+	}
+	return nil
+}
+
+func newContainer() *container {
+	c := new(container)
+	hwnd := C.newContainer(unsafe.Pointer(c))
+	if hwnd != c.hwnd {
+		panic(fmt.Errorf("inconsistency: hwnd returned by CreateWindowEx() (%p) and hwnd stored in container (%p) differ", hwnd, c.hwnd))
+	}
+	// don't set preferredSize(); it should never be called
+	return c
+}
+
+// TODO merge with controlSingleHWND
+func (c *container) show() {
+	C.ShowWindow(c.hwnd, C.SW_SHOW)
+}
+
+// TODO merge with controlSingleHWND
+func (c *container) hide() {
+	C.ShowWindow(c.hwnd, C.SW_HIDE)
+}
+
+//export storeContainerHWND
+func storeContainerHWND(data unsafe.Pointer, hwnd C.HWND) {
+	c := (*container)(data)
+	c.hwnd = hwnd
+}
+
+// For Windows, Microsoft just hands you a list of preferred control sizes as part of the MSDN documentation and tells you to roll with it.
+// These sizes are given in "dialog units", which are independent of the font in use.
+// We need to convert these into standard pixels, which requires we get the device context of the OS window.
+// References:
+// - http://msdn.microsoft.com/en-us/library/ms645502%28VS.85%29.aspx - the calculation needed
+// - http://support.microsoft.com/kb/125681 - to get the base X and Y
+// (thanks to http://stackoverflow.com/questions/58620/default-button-size)
+// In my tests (see https://github.com/andlabs/windlgunits), the GetTextExtentPoint32() option for getting the base X produces much more accurate results than the tmAveCharWidth option when tested against the sample values given in http://msdn.microsoft.com/en-us/library/windows/desktop/dn742486.aspx#sizingandspacing, but can be off by a pixel in either direction (probably due to rounding errors).
+
+// 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 (
+	// TODO figure out how to sort this more nicely
+	marginDialogUnits  = 7
+	paddingDialogUnits = 4
+
+	// TODO move to group
+	groupXMargin       = 6
+	groupYMarginTop    = 11 // note this value /includes the groupbox label/
+	groupYMarginBottom = 7
+)
+
+func (w *window) beginResize() (d *sizing) {
+	var baseX, baseY C.int
+	var internalLeading C.LONG
+
+	d = new(sizing)
+
+	C.calculateBaseUnits(c.hwnd, &baseX, &baseY, &internalLeading)
+	d.baseX = baseX
+	d.baseY = baseY
+	d.internalLeading = internalLeading
+
+	d.xmargin = fromdlgunitsX(marginDialogUnits, d)
+	d.ymargintop = fromdlgunitsY(marginDialogUnits, d)
+	d.ymarginbottom = d.ymargintop
+	d.xpadding = fromdlgunitsX(paddingDialogUnits, d)
+	d.ypadding = fromdlgunitsY(paddingDialogUnits, d)
+
+/*TODO
+	if c.isGroup {
+		// note that these values apply regardless of whether or not spaced is set
+		// this is because Windows groupboxes have the client rect spanning the entire size of the control, not just the active work area
+		// the measurements Microsoft give us are for spaced margining; let's just use them
+		d.xmargin = fromdlgunitsX(groupXMargin, d)
+		d.ymargintop = fromdlgunitsY(groupYMarginTop, d)
+		d.ymarginbottom = fromdlgunitsY(groupYMarginBottom, d)
+
+	}
+*/
+
+	return d
+}