andlabs-ui/control.go

133 lines
3.1 KiB
Go

// 12 december 2015
package ui
import (
"unsafe"
)
// #include "ui.h"
import "C"
// no need to lock this; only the GUI thread can access it
var controls = make(map[*C.uiControl]Control)
// Control represents a GUI control. It provdes methods
// common to all Controls.
//
// The preferred way to create new Controls is to use
// ControlBase; see ControlBase below.
type Control interface {
// Destroy destroys the Control.
Destroy()
// Handle returns the OS-level handle that backs the
// Control. On OSs that use reference counting for
// controls, Handle does not increment the reference
// count; you are sharing package ui's reference.
Handle() uintptr
// Visible returns whether the Control is visible.
Visible() bool
// Show shows the Control.
Show()
// Hide shows the Control. Hidden controls do not participate
// in layout (that is, Box, Grid, etc. does not reserve space for
// hidden controls).
Hide()
// Enabled returns whether the Control is enabled.
Enabled() bool
// Enable enables the Control.
Enable()
// Disable disables the Control.
Disable()
}
// ControlBase is an implementation of Control that provides
// all the methods that Control requires. To use it, embed a
// ControlBase (not a *ControlBase) into your structure, then
// assign the result of NewControlBase to that field:
//
// type MyControl struct {
// ui.ControlBase
// c *C.MyControl
// }
//
// func NewMyControl() *MyControl {
// m := &NewMyControl{
// c: C.newMyControl(),
// }
// m.ControlBase = ui.NewControlBase(m, uintptr(unsafe.Pointer(c)))
// return m
// }
type ControlBase struct {
iface Control
c *C.uiControl
}
// NewControlBase creates a new ControlBase. See the
// documentation of ControlBase for an example.
// NewControl should only be called once per instance of Control.
func NewControlBase(iface Control, c uintptr) ControlBase {
b := ControlBase{
iface: iface,
c: (*C.uiControl)(unsafe.Pointer(c)),
}
controls[b.c] = b.iface
return b
}
func (c *ControlBase) Destroy() {
delete(controls, c.c)
C.uiControlDestroy(c.c)
}
func (c *ControlBase) Handle() uintptr {
return uintptr(C.uiControlHandle(c.c))
}
func (c *ControlBase) Visible() bool {
return tobool(C.uiControlVisible(c.c))
}
func (c *ControlBase) Show() {
C.uiControlShow(c.c)
}
func (c *ControlBase) Hide() {
C.uiControlHide(c.c)
}
func (c *ControlBase) Enabled() bool {
return tobool(C.uiControlEnabled(c.c))
}
func (c *ControlBase) Enable() {
C.uiControlEnable(c.c)
}
func (c *ControlBase) Disable() {
C.uiControlDisable(c.c)
}
// ControlFromLibui returns the Control associated with a libui
// uiControl. This is intended for implementing event handlers
// on the Go side, to prevent sharing Go pointers with C.
// This function only works on Controls that use ControlBase.
func ControlFromLibui(c uintptr) Control {
// comma-ok form to avoid creating nil entries
c, _ := controls[(*C.uiControl)(unsafe.Pointer(c))]
return c
}
// LibuiFreeText allows implementations of Control
// to call the libui function uiFreeText.
func LibuiFreeText(c uintptr) {
C.uiFreeText((*C.char)(unsafe.Pointer(c)))
}