Use alternate screen only when the value of height is 100%

Do not automatically decide to use alternate screen when the value of
height exceeds the height of the terminal.

    # Use alternate screen
    fzf
    fzf --height 100%
    fzf --no-height

    # Still use current screen
    fzf --height 10000

src/terminal.go

@@ -295,7 +295,14 @@ func NewTerminal(opts *Options, eventBox *util.EventBox) *Terminal {
 		strongAttr = tui.AttrRegular
 	}
 	var renderer tui.Renderer
-	if opts.Height.size > 0 {
+	if opts.Height.size == 0 || opts.Height.percent && opts.Height.size == 100 {
+		if tui.HasFullscreenRenderer() {
+			renderer = tui.NewFullscreenRenderer(opts.Theme, opts.Black, opts.Mouse)
+		} else {
+			renderer = tui.NewLightRenderer(opts.Theme, opts.Black, opts.Mouse, opts.Tabstop, opts.ClearOnExit,
+				true, func(h int) int { return h })
+		}
+	} else {
 		maxHeightFunc := func(termHeight int) int {
 			var maxHeight int
 			if opts.Height.percent {
@@ -316,12 +323,7 @@ func NewTerminal(opts *Options, eventBox *util.EventBox) *Terminal {
 			}
 			return util.Min(termHeight, util.Max(maxHeight, effectiveMinHeight))
 		}
-		renderer = tui.NewLightRenderer(opts.Theme, opts.Black, opts.Mouse, opts.Tabstop, opts.ClearOnExit, maxHeightFunc)
+		renderer = tui.NewLightRenderer(opts.Theme, opts.Black, opts.Mouse, opts.Tabstop, opts.ClearOnExit, false, maxHeightFunc)
-	} else if tui.HasFullscreenRenderer() {
-		renderer = tui.NewFullscreenRenderer(opts.Theme, opts.Black, opts.Mouse)
-	} else {
-		renderer = tui.NewLightRenderer(opts.Theme, opts.Black, opts.Mouse, opts.Tabstop, opts.ClearOnExit,
-			func(h int) int { return h })
 	}
 	wordRubout := "[^[:alnum:]][[:alnum:]]"
 	wordNext := "[[:alnum:]][^[:alnum:]]|(.$)"

src/tui/light.go

@@ -107,7 +107,7 @@ type LightWindow struct {
 	bg       Color
 }
 
-func NewLightRenderer(theme *ColorTheme, forceBlack bool, mouse bool, tabstop int, clearOnExit bool, maxHeightFunc func(int) int) Renderer {
+func NewLightRenderer(theme *ColorTheme, forceBlack bool, mouse bool, tabstop int, clearOnExit bool, fullscreen bool, maxHeightFunc func(int) int) Renderer {
 	r := LightRenderer{
 		theme:         theme,
 		forceBlack:    forceBlack,
@@ -116,7 +116,7 @@ func NewLightRenderer(theme *ColorTheme, forceBlack bool, mouse bool, tabstop in
 		ttyin:         openTtyIn(),
 		yoffset:       0,
 		tabstop:       tabstop,
-		fullscreen:    false,
+		fullscreen:    fullscreen,
 		upOneLine:     false,
 		maxHeightFunc: maxHeightFunc}
 	return &r
@@ -176,11 +176,7 @@ func (r *LightRenderer) Init() {
 	}
 	r.origState = origState
 	terminal.MakeRaw(fd)
-	terminalHeight, capHeight := r.updateTerminalSize()
+	r.updateTerminalSize()
-	if capHeight == terminalHeight {
-		r.fullscreen = true
-		r.height = terminalHeight
-	}
 	initTheme(r.theme, r.defaultTheme(), r.forceBlack)
 
 	if r.fullscreen {
@@ -242,20 +238,15 @@ func getEnv(name string, defaultValue int) int {
 	return atoi(env, defaultValue)
 }
 
-func (r *LightRenderer) updateTerminalSize() (int, int) {
+func (r *LightRenderer) updateTerminalSize() {
 	width, height, err := terminal.GetSize(r.fd())
 	if err == nil {
 		r.width = width
-		if r.fullscreen {
+		r.height = r.maxHeightFunc(height)
-			r.height = height
-		} else {
-			r.height = r.maxHeightFunc(height)
-		}
 	} else {
 		r.width = getEnv("COLUMNS", defaultWidth)
 		r.height = r.maxHeightFunc(getEnv("LINES", defaultHeight))
 	}
-	return height, r.height
 }
 
 func (r *LightRenderer) getch(nonblock bool) (int, bool) {