133 lines
3.8 KiB
Go
133 lines
3.8 KiB
Go
// 4 august 2014
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package ui
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import (
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"fmt"
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"syscall"
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"unsafe"
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)
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// #include "winapi_windows.h"
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import "C"
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type container struct {
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containerbase
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hwnd C.HWND
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nchildren int
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}
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type sizing struct {
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sizingbase
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// for size calculations
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baseX C.int
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baseY C.int
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internalLeading C.LONG // for Label; see Label.commitResize() for details
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// for the actual resizing
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// possibly the HDWP
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}
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func makeContainerWindowClass() error {
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var errmsg *C.char
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err := C.makeContainerWindowClass(&errmsg)
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if err != 0 || errmsg != nil {
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return fmt.Errorf("%s: %v", C.GoString(errmsg), syscall.Errno(err))
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}
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return nil
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}
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func newContainer(control Control) *container {
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c := new(container)
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hwnd := C.newContainer(unsafe.Pointer(c))
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if hwnd != c.hwnd {
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panic(fmt.Errorf("inconsistency: hwnd returned by CreateWindowEx() (%p) and hwnd stored in container (%p) differ", hwnd, c.hwnd))
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}
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c.child = control
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c.child.setParent(&controlParent{c})
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return c
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}
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func (c *container) setParent(hwnd C.HWND) {
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C.controlSetParent(c.hwnd, hwnd)
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}
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// this is needed because Windows won't move/resize a child window for us
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func (c *container) move(r *C.RECT) {
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C.moveWindow(c.hwnd, C.int(r.left), C.int(r.top), C.int(r.right - r.left), C.int(r.bottom - r.top))
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}
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func (c *container) show() {
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C.ShowWindow(c.hwnd, C.SW_SHOW)
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}
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func (c *container) hide() {
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C.ShowWindow(c.hwnd, C.SW_HIDE)
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}
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//export storeContainerHWND
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func storeContainerHWND(data unsafe.Pointer, hwnd C.HWND) {
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c := (*container)(data)
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c.hwnd = hwnd
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}
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//export containerResize
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func containerResize(data unsafe.Pointer, r *C.RECT) {
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c := (*container)(data)
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// the origin of any window's content area is always (0, 0), but let's use the values from the RECT just to be safe
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c.resize(int(r.left), int(r.top), int(r.right - r.left), int(r.bottom - r.top))
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}
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// 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.
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// These sizes are given in "dialog units", which are independent of the font in use.
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// We need to convert these into standard pixels, which requires we get the device context of the OS window.
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// References:
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// - http://msdn.microsoft.com/en-us/library/ms645502%28VS.85%29.aspx - the calculation needed
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// - http://support.microsoft.com/kb/125681 - to get the base X and Y
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// (thanks to http://stackoverflow.com/questions/58620/default-button-size)
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// 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).
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// note on MulDiv():
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// div will not be 0 in the usages below
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// we also ignore overflow; that isn't likely to happen for our use case anytime soon
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func fromdlgunitsX(du int, d *sizing) int {
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return int(C.MulDiv(C.int(du), d.baseX, 4))
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}
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func fromdlgunitsY(du int, d *sizing) int {
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return int(C.MulDiv(C.int(du), d.baseY, 8))
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}
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const (
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marginDialogUnits = 7
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paddingDialogUnits = 4
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)
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func (c *container) beginResize() (d *sizing) {
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var baseX, baseY C.int
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var internalLeading C.LONG
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d = new(sizing)
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C.calculateBaseUnits(c.hwnd, &baseX, &baseY, &internalLeading)
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d.baseX = baseX
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d.baseY = baseY
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d.internalLeading = internalLeading
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if spaced {
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d.xmargin = fromdlgunitsX(marginDialogUnits, d)
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d.ymargin = fromdlgunitsY(marginDialogUnits, d)
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d.xpadding = fromdlgunitsX(paddingDialogUnits, d)
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d.ypadding = fromdlgunitsY(paddingDialogUnits, d)
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}
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return d
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}
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func (c *container) translateAllocationCoords(allocations []*allocation, winwidth, winheight int) {
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// no translation needed on windows
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}
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