Add --margin option

Close #299

CHANGELOG.md

@@ -6,6 +6,7 @@ CHANGELOG
 
 ### New features
 
+- Added `--margin` option
 - Added options for sticky header
     - `--header-file`
     - `--header-lines`

man/man1/fzf.1

@@ -131,6 +131,31 @@ Use black background
 .B "--reverse"
 Reverse orientation
 .TP
+.BI "--margin=" MARGIN
+Comma-separated expression for margins around the finder.
+.br
+.R ""
+.br
+.RS
+.BR TRBL "     Same margin for top, right, bottom, and left"
+.br
+.BR TB,RL "    Vertical, horizontal margin"
+.br
+.BR T,RL,B "   Top, horizontal, bottom margin"
+.br
+.BR T,R,B,L "  Top, right, bottom, left margin"
+.br
+.R ""
+.br
+Each part can be given in absolute number or in percentage relative to the
+terminal size with \fB%\fR suffix.
+.br
+.R ""
+.br
+e.g. \fBfzf --margin 10%\fR
+     \fBfzf --margin 1,5%\fR
+.RE
+.TP
 .B "--cycle"
 Enable cyclic scroll
 .TP

shell/completion.bash

@@ -50,7 +50,8 @@ _fzf_opts_completion() {
     --history
     --history-size
     --header-file
-    --header-lines"
+    --header-lines
+    --margin"
 
   case "${prev}" in
   --tiebreak)

src/options.go

@@ -38,6 +38,7 @@ const usage = `usage: fzf [options]
     --color=COLSPEC       Base scheme (dark|light|16|bw) and/or custom colors
     --black               Use black background
     --reverse             Reverse orientation
+    --margin=MARGIN       Screen margin (TRBL / TB,RL / T,RL,B / T,R,B,L)
     --cycle               Enable cyclic scroll
     --no-hscroll          Disable horizontal scroll
     --inline-info         Display finder info inline with the query
@@ -93,6 +94,10 @@ const (
 	byIndex
 )
 
+func defaultMargin() [4]string {
+	return [4]string{"0", "0", "0", "0"}
+}
+
 // Options stores the values of command-line options
 type Options struct {
 	Mode        Mode
@@ -127,6 +132,7 @@ type Options struct {
 	History     *History
 	Header      []string
 	HeaderLines int
+	Margin      [4]string
 	Version     bool
 }
 
@@ -171,6 +177,7 @@ func defaultOptions() *Options {
 		History:     nil,
 		Header:      make([]string, 0),
 		HeaderLines: 0,
+		Margin:      defaultMargin(),
 		Version:     false}
 }
 
@@ -218,6 +225,14 @@ func atoi(str string) int {
 	return num
 }
 
+func atof(str string) float64 {
+	num, err := strconv.ParseFloat(str, 64)
+	if err != nil {
+		errorExit("not a valid number: " + str)
+	}
+	return num
+}
+
 func nextInt(args []string, i *int, message string) int {
 	if len(args) > *i+1 {
 		*i++
@@ -592,6 +607,48 @@ func readHeaderFile(filename string) []string {
 	return strings.Split(strings.TrimSuffix(string(content), "\n"), "\n")
 }
 
+func parseMargin(margin string) [4]string {
+	margins := strings.Split(margin, ",")
+	checked := func(str string) string {
+		if strings.HasSuffix(str, "%") {
+			val := atof(str[:len(str)-1])
+			if val < 0 {
+				errorExit("margin must be non-negative")
+			}
+			if val > 100 {
+				errorExit("margin too large")
+			}
+		} else {
+			val := atoi(str)
+			if val < 0 {
+				errorExit("margin must be non-negative")
+			}
+		}
+		return str
+	}
+	switch len(margins) {
+	case 1:
+		m := checked(margins[0])
+		return [4]string{m, m, m, m}
+	case 2:
+		tb := checked(margins[0])
+		rl := checked(margins[1])
+		return [4]string{tb, rl, tb, rl}
+	case 3:
+		t := checked(margins[0])
+		rl := checked(margins[1])
+		b := checked(margins[2])
+		return [4]string{t, rl, b, rl}
+	case 4:
+		return [4]string{
+			checked(margins[0]), checked(margins[1]),
+			checked(margins[2]), checked(margins[3])}
+	default:
+		errorExit("invalid margin: " + margin)
+	}
+	return defaultMargin()
+}
+
 func parseOptions(opts *Options, allArgs []string) {
 	keymap := make(map[int]actionType)
 	var historyMax int
@@ -743,6 +800,11 @@ func parseOptions(opts *Options, allArgs []string) {
 			opts.Header = []string{}
 			opts.HeaderLines = atoi(
 				nextString(allArgs, &i, "number of header lines required"))
+		case "--no-margin":
+			opts.Margin = defaultMargin()
+		case "--margin":
+			opts.Margin = parseMargin(
+				nextString(allArgs, &i, "margin required (TRBL / TB,RL / T,RL,B / T,R,B,L)"))
 		case "--version":
 			opts.Version = true
 		default:
@@ -782,6 +844,8 @@ func parseOptions(opts *Options, allArgs []string) {
 			} else if match, value := optString(arg, "--header-lines="); match {
 				opts.Header = []string{}
 				opts.HeaderLines = atoi(value)
+			} else if match, value := optString(arg, "--margin="); match {
+				opts.Margin = parseMargin(value)
 			} else {
 				errorExit("unknown option: " + arg)
 			}

src/terminal.go

@@ -8,6 +8,7 @@ import (
 	"os/signal"
 	"regexp"
 	"sort"
+	"strconv"
 	"strings"
 	"sync"
 	"syscall"
@@ -41,6 +42,8 @@ type Terminal struct {
 	history    *History
 	cycle      bool
 	header     []string
+	margin     [4]string
+	marginInt  [4]int
 	count      int
 	progress   int
 	reading    bool
@@ -200,6 +203,8 @@ func NewTerminal(opts *Options, eventBox *util.EventBox) *Terminal {
 		pressed:    "",
 		printQuery: opts.PrintQuery,
 		history:    opts.History,
+		margin:     opts.Margin,
+		marginInt:  [4]int{0, 0, 0, 0},
 		cycle:      opts.Cycle,
 		header:     opts.Header,
 		reading:    true,
@@ -317,10 +322,50 @@ func displayWidth(runes []rune) int {
 	return l
 }
 
+const minWidth = 16
+const minHeight = 4
+
+func (t *Terminal) calculateMargins() {
+	screenWidth := C.MaxX()
+	screenHeight := C.MaxY()
+	for idx, str := range t.margin {
+		if str == "0" {
+			t.marginInt[idx] = 0
+		} else if strings.HasSuffix(str, "%") {
+			num, _ := strconv.ParseFloat(str[:len(str)-1], 64)
+			var val float64
+			if idx%2 == 0 {
+				val = float64(screenHeight)
+			} else {
+				val = float64(screenWidth)
+			}
+			t.marginInt[idx] = int(val * num * 0.01)
+		} else {
+			num, _ := strconv.Atoi(str)
+			t.marginInt[idx] = num
+		}
+	}
+	adjust := func(idx1 int, idx2 int, max int, min int) {
+		if max >= min {
+			margin := t.marginInt[idx1] + t.marginInt[idx2]
+			if max-margin < min {
+				desired := max - min
+				t.marginInt[idx1] = desired * t.marginInt[idx1] / margin
+				t.marginInt[idx2] = desired * t.marginInt[idx2] / margin
+			}
+		}
+	}
+	adjust(1, 3, screenWidth, minWidth)
+	adjust(0, 2, screenHeight, minHeight)
+}
+
 func (t *Terminal) move(y int, x int, clear bool) {
+	x += t.marginInt[3]
 	maxy := C.MaxY()
 	if !t.reverse {
-		y = maxy - y - 1
+		y = maxy - y - 1 - t.marginInt[2]
+	} else {
+		y += t.marginInt[0]
 	}
 
 	if clear {
@@ -375,11 +420,15 @@ func (t *Terminal) printInfo() {
 	C.CPrint(C.ColInfo, false, output)
 }
 
+func (t *Terminal) maxHeight() int {
+	return C.MaxY() - t.marginInt[0] - t.marginInt[2]
+}
+
 func (t *Terminal) printHeader() {
 	if len(t.header) == 0 {
 		return
 	}
-	max := C.MaxY()
+	max := t.maxHeight()
 	var state *ansiState
 	for idx, lineStr := range t.header {
 		if !t.reverse {
@@ -490,7 +539,7 @@ func (t *Terminal) printHighlighted(item *Item, bold bool, col1 int, col2 int, c
 	// Overflow
 	text := []rune(*item.text)
 	offsets := item.colorOffsets(col2, bold, current)
-	maxWidth := C.MaxX() - 3
+	maxWidth := C.MaxX() - 3 - t.marginInt[1] - t.marginInt[3]
 	fullWidth := displayWidth(text)
 	if fullWidth > maxWidth {
 		if t.hscroll {
@@ -573,6 +622,7 @@ func processTabs(runes []rune, prefixWidth int) (string, int) {
 }
 
 func (t *Terminal) printAll() {
+	t.calculateMargins()
 	t.printList()
 	t.printPrompt()
 	t.printInfo()
@@ -652,6 +702,7 @@ func (t *Terminal) Loop() {
 	{ // Late initialization
 		t.mutex.Lock()
 		t.initFunc()
+		t.calculateMargins()
 		t.printPrompt()
 		t.placeCursor()
 		C.Refresh()
@@ -942,40 +993,46 @@ func (t *Terminal) Loop() {
 			}
 		case actMouse:
 			me := event.MouseEvent
-			mx, my := util.Constrain(me.X-len(t.prompt), 0, len(t.input)), me.Y
+			mx, my := me.X, me.Y
-			if !t.reverse {
+			if mx >= t.marginInt[3] && mx < C.MaxX()-t.marginInt[1] &&
-				my = C.MaxY() - my - 1
+				my >= t.marginInt[0] && my < C.MaxY()-t.marginInt[2] {
-			}
+				mx -= t.marginInt[3]
-			min := 2 + len(t.header)
+				my -= t.marginInt[0]
-			if t.inlineInfo {
+				mx = util.Constrain(mx-len(t.prompt), 0, len(t.input))
-				min -= 1
+				if !t.reverse {
-			}
+					my = t.maxHeight() - my - 1
-			if me.S != 0 {
-				// Scroll
-				if t.merger.Length() > 0 {
-					if t.multi && me.Mod {
-						toggle()
-					}
-					t.vmove(me.S)
-					req(reqList)
 				}
-			} else if me.Double {
+				min := 2 + len(t.header)
-				// Double-click
+				if t.inlineInfo {
-				if my >= min {
+					min -= 1
-					if t.vset(t.offset+my-min) && t.cy < t.merger.Length() {
-						req(reqClose)
-					}
 				}
-			} else if me.Down {
+				if me.S != 0 {
-				if my == 0 && mx >= 0 {
+					// Scroll
-					// Prompt
+					if t.merger.Length() > 0 {
-					t.cx = mx
+						if t.multi && me.Mod {
-				} else if my >= min {
+							toggle()
-					// List
+						}
-					if t.vset(t.offset+my-min) && t.multi && me.Mod {
+						t.vmove(me.S)
-						toggle()
+						req(reqList)
+					}
+				} else if me.Double {
+					// Double-click
+					if my >= min {
+						if t.vset(t.offset+my-min) && t.cy < t.merger.Length() {
+							req(reqClose)
+						}
+					}
+				} else if me.Down {
+					if my == 0 && mx >= 0 {
+						// Prompt
+						t.cx = mx
+					} else if my >= min {
+						// List
+						if t.vset(t.offset+my-min) && t.multi && me.Mod {
+							toggle()
+						}
+						req(reqList)
 					}
-					req(reqList)
 				}
 			}
 		}
@@ -1040,7 +1097,7 @@ func (t *Terminal) vset(o int) bool {
 }
 
 func (t *Terminal) maxItems() int {
-	max := C.MaxY() - 2 - len(t.header)
+	max := t.maxHeight() - 2 - len(t.header)
 	if t.inlineInfo {
 		max += 1
 	}

test/test_go.rb

@@ -731,6 +731,18 @@ class TestGoFZF < TestBase
     tmux.prepare
   end
 
+  def test_margin
+    tmux.send_keys "yes | head -1000 | #{fzf "--margin 5,3"}", :Enter
+    tmux.until { |lines| lines[4] == '' && lines[5] == '     y' }
+    tmux.send_keys :Enter
+  end
+
+  def test_margin_reverse
+    tmux.send_keys "seq 1000 | #{fzf "--margin 7,5 --reverse"}", :Enter
+    tmux.until { |lines| lines[1 + 7] == '       1000/1000' }
+    tmux.send_keys :Enter
+  end
+
 private
   def writelines path, lines
     File.unlink path while File.exists? path