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gcz/survey/terminal/cursor_windows.go

164 lines
4.0 KiB

package terminal
import (
"bytes"
"syscall"
"unsafe"
)
var COORDINATE_SYSTEM_BEGIN Short = 0
// shared variable to save the cursor location from CursorSave()
var cursorLoc Coord
type Cursor struct {
In FileReader
Out FileWriter
}
func (c *Cursor) Up(n int) error {
return c.cursorMove(0, n)
}
func (c *Cursor) Down(n int) error {
return c.cursorMove(0, -1*n)
}
func (c *Cursor) Forward(n int) error {
return c.cursorMove(n, 0)
}
func (c *Cursor) Back(n int) error {
return c.cursorMove(-1*n, 0)
}
// save the cursor location
func (c *Cursor) Save() error {
loc, err := c.Location(nil)
if err != nil {
return err
}
cursorLoc = *loc
return nil
}
func (c *Cursor) Restore() error {
handle := syscall.Handle(c.Out.Fd())
// restore it to the original position
_, _, err := procSetConsoleCursorPosition.Call(uintptr(handle), uintptr(*(*int32)(unsafe.Pointer(&cursorLoc))))
return normalizeError(err)
}
func (cur Coord) CursorIsAtLineEnd(size *Coord) bool {
return cur.X == size.X
}
func (cur Coord) CursorIsAtLineBegin() bool {
return cur.X == 0
}
func (c *Cursor) cursorMove(x int, y int) error {
handle := syscall.Handle(c.Out.Fd())
var csbi consoleScreenBufferInfo
if _, _, err := procGetConsoleScreenBufferInfo.Call(uintptr(handle), uintptr(unsafe.Pointer(&csbi))); normalizeError(err) != nil {
return err
}
var cursor Coord
cursor.X = csbi.cursorPosition.X + Short(x)
cursor.Y = csbi.cursorPosition.Y + Short(y)
_, _, err := procSetConsoleCursorPosition.Call(uintptr(handle), uintptr(*(*int32)(unsafe.Pointer(&cursor))))
return normalizeError(err)
}
func (c *Cursor) NextLine(n int) error {
if err := c.Up(n); err != nil {
return err
}
return c.HorizontalAbsolute(0)
}
func (c *Cursor) PreviousLine(n int) error {
if err := c.Down(n); err != nil {
return err
}
return c.HorizontalAbsolute(0)
}
// for comparability purposes between windows
// in windows we don't have to print out a new line
func (c *Cursor) MoveNextLine(cur *Coord, terminalSize *Coord) error {
return c.NextLine(1)
}
func (c *Cursor) HorizontalAbsolute(x int) error {
handle := syscall.Handle(c.Out.Fd())
var csbi consoleScreenBufferInfo
if _, _, err := procGetConsoleScreenBufferInfo.Call(uintptr(handle), uintptr(unsafe.Pointer(&csbi))); normalizeError(err) != nil {
return err
}
var cursor Coord
cursor.X = Short(x)
cursor.Y = csbi.cursorPosition.Y
if csbi.size.X < cursor.X {
cursor.X = csbi.size.X
}
_, _, err := procSetConsoleCursorPosition.Call(uintptr(handle), uintptr(*(*int32)(unsafe.Pointer(&cursor))))
return normalizeError(err)
}
func (c *Cursor) Show() error {
handle := syscall.Handle(c.Out.Fd())
var cci consoleCursorInfo
if _, _, err := procGetConsoleCursorInfo.Call(uintptr(handle), uintptr(unsafe.Pointer(&cci))); normalizeError(err) != nil {
return err
}
cci.visible = 1
_, _, err := procSetConsoleCursorInfo.Call(uintptr(handle), uintptr(unsafe.Pointer(&cci)))
return normalizeError(err)
}
func (c *Cursor) Hide() error {
handle := syscall.Handle(c.Out.Fd())
var cci consoleCursorInfo
if _, _, err := procGetConsoleCursorInfo.Call(uintptr(handle), uintptr(unsafe.Pointer(&cci))); normalizeError(err) != nil {
return err
}
cci.visible = 0
_, _, err := procSetConsoleCursorInfo.Call(uintptr(handle), uintptr(unsafe.Pointer(&cci)))
return normalizeError(err)
}
func (c *Cursor) Location(buf *bytes.Buffer) (*Coord, error) {
handle := syscall.Handle(c.Out.Fd())
var csbi consoleScreenBufferInfo
if _, _, err := procGetConsoleScreenBufferInfo.Call(uintptr(handle), uintptr(unsafe.Pointer(&csbi))); normalizeError(err) != nil {
return nil, err
}
return &csbi.cursorPosition, nil
}
func (c *Cursor) Size(buf *bytes.Buffer) (*Coord, error) {
handle := syscall.Handle(c.Out.Fd())
var csbi consoleScreenBufferInfo
if _, _, err := procGetConsoleScreenBufferInfo.Call(uintptr(handle), uintptr(unsafe.Pointer(&csbi))); normalizeError(err) != nil {
return nil, err
}
// windows' coordinate system begins at (0, 0)
csbi.size.X--
csbi.size.Y--
return &csbi.size, nil
}