andlabs-ui/prev/button_windows.go

72 lines
1.6 KiB
Go

// 15 july 2014
package ui
import (
"unsafe"
)
// #include "winapi_windows.h"
import "C"
type button struct {
*controlSingleHWNDWithText
clicked *event
}
var buttonclass = toUTF16("BUTTON")
func newButton(text string) *button {
hwnd := C.newControl(buttonclass,
C.BS_PUSHBUTTON|C.WS_TABSTOP,
0)
b := &button{
controlSingleHWNDWithText: newControlSingleHWNDWithText(hwnd),
clicked: newEvent(),
}
b.fpreferredSize = b.xpreferredSize
b.SetText(text)
C.controlSetControlFont(b.hwnd)
C.setButtonSubclass(b.hwnd, unsafe.Pointer(b))
return b
}
func (b *button) OnClicked(e func()) {
b.clicked.set(e)
}
func (b *button) Text() string {
return b.text()
}
func (b *button) SetText(text string) {
b.setText(text)
}
//export buttonClicked
func buttonClicked(data unsafe.Pointer) {
b := (*button)(data)
b.clicked.fire()
}
const (
// from http://msdn.microsoft.com/en-us/library/windows/desktop/dn742486.aspx#sizingandspacing
buttonHeight = 14
)
func (b *button) xpreferredSize(d *sizing) (width, height int) {
// comctl32.dll version 6 thankfully provides a method to grab this...
var size C.SIZE
size.cx = 0 // explicitly ask for ideal size
size.cy = 0
if C.SendMessageW(b.hwnd, C.BCM_GETIDEALSIZE, 0, C.LPARAM(uintptr(unsafe.Pointer(&size)))) != C.FALSE {
return int(size.cx), int(size.cy)
}
// that failed, fall back
println("message failed; falling back")
// don't worry about the error return from GetSystemMetrics(); there's no way to tell (explicitly documented as such)
xmargins := 2 * int(C.GetSystemMetrics(C.SM_CXEDGE))
return xmargins + int(b.textlen), fromdlgunitsY(buttonHeight, d)
}