Add --padding option

Close #2241

5 files changed, 89 insertions, 24 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4b41fd4b..a305ecc7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,14 @@
 CHANGELOG
 =========
 
+0.24.3
+------
+- Added `--padding` option
+  ```sh
+  fzf --margin 5% --padding 5% --border --preview 'cat {}' \
+      --color bg:#222222,preview-bg:#333333
+  ```
+
 0.24.2
 ------
 - Bug fixes and improvements
diff --git a/man/man1/fzf-tmux.1 b/man/man1/fzf-tmux.1
index c147dde8..25465424 100644
--- a/man/man1/fzf-tmux.1
+++ b/man/man1/fzf-tmux.1
@@ -21,7 +21,7 @@ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 ..
-.TH fzf-tmux 1 "Nov 2020" "fzf 0.24.2" "fzf-tmux - open fzf in tmux split pane"
+.TH fzf-tmux 1 "Nov 2020" "fzf 0.24.3" "fzf-tmux - open fzf in tmux split pane"
 
 .SH NAME
 fzf-tmux - open fzf in tmux split pane
diff --git a/man/man1/fzf.1 b/man/man1/fzf.1
index 32f54840..99147403 100644
--- a/man/man1/fzf.1
+++ b/man/man1/fzf.1
@@ -21,7 +21,7 @@ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 ..
-.TH fzf 1 "Nov 2020" "fzf 0.24.2" "fzf - a command-line fuzzy finder"
+.TH fzf 1 "Nov 2020" "fzf 0.24.3" "fzf - a command-line fuzzy finder"
 
 .SH NAME
 fzf - a command-line fuzzy finder
@@ -234,6 +234,29 @@ e.g.
      fzf --margin 1,5%\fR
 .RE
 .TP
+.BI "--padding=" PADDING
+Comma-separated expression for padding inside the border. Padding is
+distinguishable from margin only when \fB--border\fR option is used.
+.br
+
+.br
+e.g.
+     \fBfzf --margin 5% --padding 5% --border --preview 'cat {}' \\
+         --color bg:#222222,preview-bg:#333333\fR
+
+.br
+.RS
+.BR TRBL "     Same padding for top, right, bottom, and left"
+.br
+.BR TB,RL "    Vertical, horizontal padding"
+.br
+.BR T,RL,B "   Top, horizontal, bottom padding"
+.br
+.BR T,R,B,L "  Top, right, bottom, left padding"
+.br
+.RE
+
+.TP
 .BI "--info=" "STYLE"
 Determines the display style of finder info.
 
diff --git a/src/options.go b/src/options.go
index 797863cf..d7e1eaa6 100644
--- a/src/options.go
+++ b/src/options.go
@@ -60,7 +60,8 @@ const usage = `usage: fzf [options]
     --border[=STYLE]      Draw border around the finder
                           [rounded|sharp|horizontal|vertical|
                            top|bottom|left|right] (default: rounded)
-    --margin=MARGIN       Screen margin (TRBL / TB,RL / T,RL,B / T,R,B,L)
+    --margin=MARGIN       Screen margin (TRBL | TB,RL | T,RL,B | T,R,B,L)
+    --padding=PADDING     Padding inside border (TRBL | TB,RL | T,RL,B | T,R,B,L)
     --info=STYLE          Finder info style [default|inline|hidden]
     --prompt=STR          Input prompt (default: '> ')
     --pointer=STR         Pointer to the current line (default: '>')
@@ -221,6 +222,7 @@ type Options struct {
 	Header      []string
 	HeaderLines int
 	Margin      [4]sizeSpec
+	Padding     [4]sizeSpec
 	BorderShape tui.BorderShape
 	Unicode     bool
 	Tabstop     int
@@ -281,6 +283,7 @@ func defaultOptions() *Options {
 		Header:      make([]string, 0),
 		HeaderLines: 0,
 		Margin:      defaultMargin(),
+		Padding:     defaultMargin(),
 		Unicode:     true,
 		Tabstop:     8,
 		ClearOnExit: true,
@@ -1076,10 +1079,10 @@ func parsePreviewWindow(opts *previewOpts, input string) {
 	}
 }
 
-func parseMargin(margin string) [4]sizeSpec {
+func parseMargin(opt string, margin string) [4]sizeSpec {
 	margins := strings.Split(margin, ",")
 	checked := func(str string) sizeSpec {
-		return parseSize(str, 49, "margin")
+		return parseSize(str, 49, opt)
 	}
 	switch len(margins) {
 	case 1:
@@ -1099,7 +1102,7 @@ func parseMargin(margin string) [4]sizeSpec {
 			checked(margins[0]), checked(margins[1]),
 			checked(margins[2]), checked(margins[3])}
 	default:
-		errorExit("invalid margin: " + margin)
+		errorExit("invalid " + opt + ": " + margin)
 	}
 	return defaultMargin()
 }
@@ -1324,6 +1327,8 @@ func parseOptions(opts *Options, allArgs []string) {
 			opts.Height = sizeSpec{}
 		case "--no-margin":
 			opts.Margin = defaultMargin()
+		case "--no-padding":
+			opts.Padding = defaultMargin()
 		case "--no-border":
 			opts.BorderShape = tui.BorderNone
 		case "--border":
@@ -1335,7 +1340,12 @@ func parseOptions(opts *Options, allArgs []string) {
 			opts.Unicode = true
 		case "--margin":
 			opts.Margin = parseMargin(
+				"margin",
 				nextString(allArgs, &i, "margin required (TRBL / TB,RL / T,RL,B / T,R,B,L)"))
+		case "--padding":
+			opts.Padding = parseMargin(
+				"padding",
+				nextString(allArgs, &i, "padding required (TRBL / TB,RL / T,RL,B / T,R,B,L)"))
 		case "--tabstop":
 			opts.Tabstop = nextInt(allArgs, &i, "tab stop required")
 		case "--clear":
@@ -1404,7 +1414,9 @@ func parseOptions(opts *Options, allArgs []string) {
 			} else if match, value := optString(arg, "--preview-window="); match {
 				parsePreviewWindow(&opts.Preview, value)
 			} else if match, value := optString(arg, "--margin="); match {
-				opts.Margin = parseMargin(value)
+				opts.Margin = parseMargin("margin", value)
+			} else if match, value := optString(arg, "--padding="); match {
+				opts.Padding = parseMargin("padding", value)
 			} else if match, value := optString(arg, "--tabstop="); match {
 				opts.Tabstop = atoi(value)
 			} else if match, value := optString(arg, "--hscroll-off="); match {
diff --git a/src/terminal.go b/src/terminal.go
index 10b1bac5..0a174822 100644
--- a/src/terminal.go
+++ b/src/terminal.go
@@ -119,6 +119,7 @@ type Terminal struct {
 	ansi         bool
 	tabstop      int
 	margin       [4]sizeSpec
+	padding      [4]sizeSpec
 	strong       tui.Attr
 	unicode      bool
 	borderShape  tui.BorderShape
@@ -472,6 +473,7 @@ func NewTerminal(opts *Options, eventBox *util.EventBox) *Terminal {
 		printQuery:  opts.PrintQuery,
 		history:     opts.History,
 		margin:      opts.Margin,
+		padding:     opts.Padding,
 		unicode:     opts.Unicode,
 		borderShape: opts.BorderShape,
 		cleanExit:   opts.ClearOnExit,
@@ -669,52 +671,64 @@ func calculateSize(base int, size sizeSpec, occupied int, minSize int, pad int)
 func (t *Terminal) resizeWindows() {
 	screenWidth := t.tui.MaxX()
 	screenHeight := t.tui.MaxY()
-	marginInt := [4]int{} // TRBL
 	t.prevLines = make([]itemLine, screenHeight)
-	for idx, sizeSpec := range t.margin {
-		if sizeSpec.percent {
+
+	marginInt := [4]int{}  // TRBL
+	paddingInt := [4]int{} // TRBL
+	sizeSpecToInt := func(index int, spec sizeSpec) int {
+		if spec.percent {
 			var max float64
-			if idx%2 == 0 {
+			if index%2 == 0 {
 				max = float64(screenHeight)
 			} else {
 				max = float64(screenWidth)
 			}
-			marginInt[idx] = int(max * sizeSpec.size * 0.01)
-		} else {
-			marginInt[idx] = int(sizeSpec.size)
+			return int(max * spec.size * 0.01)
 		}
+		return int(spec.size)
+	}
+	for idx, sizeSpec := range t.padding {
+		paddingInt[idx] = sizeSpecToInt(idx, sizeSpec)
+	}
+
+	extraMargin := [4]int{} // TRBL
+	for idx, sizeSpec := range t.margin {
 		switch t.borderShape {
 		case tui.BorderHorizontal:
-			marginInt[idx] += 1 - idx%2
+			extraMargin[idx] += 1 - idx%2
 		case tui.BorderVertical:
-			marginInt[idx] += 2 * (idx % 2)
+			extraMargin[idx] += 2 * (idx % 2)
 		case tui.BorderTop:
 			if idx == 0 {
-				marginInt[idx]++
+				extraMargin[idx]++
 			}
 		case tui.BorderRight:
 			if idx == 1 {
-				marginInt[idx] += 2
+				extraMargin[idx] += 2
 			}
 		case tui.BorderBottom:
 			if idx == 2 {
-				marginInt[idx]++
+				extraMargin[idx]++
 			}
 		case tui.BorderLeft:
 			if idx == 3 {
-				marginInt[idx] += 2
+				extraMargin[idx] += 2
 			}
 		case tui.BorderRounded, tui.BorderSharp:
-			marginInt[idx] += 1 + idx%2
+			extraMargin[idx] += 1 + idx%2
 		}
+		marginInt[idx] = sizeSpecToInt(idx, sizeSpec) + extraMargin[idx]
 	}
+
 	adjust := func(idx1 int, idx2 int, max int, min int) {
 		if max >= min {
-			margin := marginInt[idx1] + marginInt[idx2]
+			margin := marginInt[idx1] + marginInt[idx2] + paddingInt[idx1] + paddingInt[idx2]
 			if max-margin < min {
 				desired := max - min
-				marginInt[idx1] = desired * marginInt[idx1] / margin
-				marginInt[idx2] = desired * marginInt[idx2] / margin
+				paddingInt[idx1] = desired * paddingInt[idx1] / margin
+				paddingInt[idx2] = desired * paddingInt[idx2] / margin
+				marginInt[idx1] = util.Max(extraMargin[idx1], desired*marginInt[idx1]/margin)
+				marginInt[idx2] = util.Max(extraMargin[idx2], desired*marginInt[idx2]/margin)
 			}
 		}
 	}
@@ -779,6 +793,14 @@ func (t *Terminal) resizeWindows() {
 			marginInt[0]-1, marginInt[3]-2, width+4, height+2,
 			false, tui.MakeBorderStyle(t.borderShape, t.unicode))
 	}
+
+	// Add padding
+	for idx, val := range paddingInt {
+		marginInt[idx] += val
+	}
+	width = screenWidth - marginInt[1] - marginInt[3]
+	height = screenHeight - marginInt[0] - marginInt[2]
+
 	noBorder := tui.MakeBorderStyle(tui.BorderNone, t.unicode)
 	if previewVisible {
 		createPreviewWindow := func(y int, x int, w int, h int) {