DockerCLI/vendor/github.com/Azure/go-ansiterm/winterm/scroll_helper.go

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// +build windows
package winterm
// effectiveSr gets the current effective scroll region in buffer coordinates
func (h *windowsAnsiEventHandler) effectiveSr(window SMALL_RECT) scrollRegion {
top := addInRange(window.Top, h.sr.top, window.Top, window.Bottom)
bottom := addInRange(window.Top, h.sr.bottom, window.Top, window.Bottom)
if top >= bottom {
top = window.Top
bottom = window.Bottom
}
return scrollRegion{top: top, bottom: bottom}
}
func (h *windowsAnsiEventHandler) scrollUp(param int) error {
info, err := GetConsoleScreenBufferInfo(h.fd)
if err != nil {
return err
}
sr := h.effectiveSr(info.Window)
return h.scroll(param, sr, info)
}
func (h *windowsAnsiEventHandler) scrollDown(param int) error {
return h.scrollUp(-param)
}
func (h *windowsAnsiEventHandler) deleteLines(param int) error {
info, err := GetConsoleScreenBufferInfo(h.fd)
if err != nil {
return err
}
start := info.CursorPosition.Y
sr := h.effectiveSr(info.Window)
// Lines cannot be inserted or deleted outside the scrolling region.
if start >= sr.top && start <= sr.bottom {
sr.top = start
return h.scroll(param, sr, info)
} else {
return nil
}
}
func (h *windowsAnsiEventHandler) insertLines(param int) error {
return h.deleteLines(-param)
}
// scroll scrolls the provided scroll region by param lines. The scroll region is in buffer coordinates.
func (h *windowsAnsiEventHandler) scroll(param int, sr scrollRegion, info *CONSOLE_SCREEN_BUFFER_INFO) error {
h.logf("scroll: scrollTop: %d, scrollBottom: %d", sr.top, sr.bottom)
h.logf("scroll: windowTop: %d, windowBottom: %d", info.Window.Top, info.Window.Bottom)
// Copy from and clip to the scroll region (full buffer width)
scrollRect := SMALL_RECT{
Top: sr.top,
Bottom: sr.bottom,
Left: 0,
Right: info.Size.X - 1,
}
// Origin to which area should be copied
destOrigin := COORD{
X: 0,
Y: sr.top - int16(param),
}
char := CHAR_INFO{
UnicodeChar: ' ',
Attributes: h.attributes,
}
if err := ScrollConsoleScreenBuffer(h.fd, scrollRect, scrollRect, destOrigin, char); err != nil {
return err
}
return nil
}
func (h *windowsAnsiEventHandler) deleteCharacters(param int) error {
info, err := GetConsoleScreenBufferInfo(h.fd)
if err != nil {
return err
}
return h.scrollLine(param, info.CursorPosition, info)
}
func (h *windowsAnsiEventHandler) insertCharacters(param int) error {
return h.deleteCharacters(-param)
}
// scrollLine scrolls a line horizontally starting at the provided position by a number of columns.
func (h *windowsAnsiEventHandler) scrollLine(columns int, position COORD, info *CONSOLE_SCREEN_BUFFER_INFO) error {
// Copy from and clip to the scroll region (full buffer width)
scrollRect := SMALL_RECT{
Top: position.Y,
Bottom: position.Y,
Left: position.X,
Right: info.Size.X - 1,
}
// Origin to which area should be copied
destOrigin := COORD{
X: position.X - int16(columns),
Y: position.Y,
}
char := CHAR_INFO{
UnicodeChar: ' ',
Attributes: h.attributes,
}
if err := ScrollConsoleScreenBuffer(h.fd, scrollRect, scrollRect, destOrigin, char); err != nil {
return err
}
return nil
}