text: remove padding from Editor

Before this change, the Editor computed a suitable padding for itself
from its font and text. Varying the padding according to the particular
font and text doesn't seem worth it and interferes with higher level widgets'
ability to overlay hints and the like on top of the editor.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

text/editor.go

@@ -41,22 +41,20 @@ type Editor struct {
 	// If not enabled, carriage returns are inserted as newlines in the text.
 	Submit bool
 
-	scale             int
+	scale        int
-	font              editorFont
+	font         Font
-	blinkStart        time.Time
+	blinkStart   time.Time
-	focused           bool
+	focused      bool
-	rr                editBuffer
+	rr           editBuffer
-	maxWidth          int
+	maxWidth     int
-	viewSize          image.Point
+	viewSize     image.Point
-	valid             bool
+	valid        bool
-	lines             []Line
+	lines        []Line
-	dims              layout.Dimensions
+	dims         layout.Dimensions
-	padTop, padBottom int
+	carWidth     fixed.Int26_6
-	padLeft, padRight int
+	requestFocus bool
-	carWidth          fixed.Int26_6
+	caretOn      bool
-	requestFocus      bool
+	caretScroll  bool
-	caretOn           bool
-	caretScroll       bool
 
 	// carXOff is the offset to the current caret
 	// position when moving between lines.
@@ -201,17 +199,12 @@ func (e *Editor) layout(gtx *layout.Context, s *Shaper, font Font) {
 		e.scale = scale
 	}
 	cs := gtx.Constraints
-	twoDp := gtx.Px(unit.Dp(2))
 	e.carWidth = fixed.I(gtx.Px(unit.Dp(1)))
 
-	e.padLeft, e.padRight = twoDp, twoDp
 	maxWidth := cs.Width.Max
 	if e.SingleLine {
 		maxWidth = inf
 	}
-	if maxWidth != inf {
-		maxWidth -= e.padLeft + e.padRight
-	}
 	if maxWidth != e.maxWidth {
 		e.maxWidth = maxWidth
 		e.invalidate()
@@ -232,8 +225,6 @@ func (e *Editor) layout(gtx *layout.Context, s *Shaper, font Font) {
 
 	key.InputOp{Key: e, Focus: e.requestFocus}.Add(gtx.Ops)
 	e.requestFocus = false
-
-	baseline := e.padTop + e.dims.Baseline
 	pointerPadding := gtx.Px(unit.Dp(4))
 	r := image.Rectangle{Max: e.viewSize}
 	r.Min.X -= pointerPadding
@@ -243,7 +234,6 @@ func (e *Editor) layout(gtx *layout.Context, s *Shaper, font Font) {
 	pointer.RectAreaOp{Rect: r}.Add(gtx.Ops)
 	e.scroller.Add(gtx.Ops)
 	e.clicker.Add(gtx.Ops)
-	gtx.Dimensions = layout.Dimensions{Size: e.viewSize, Baseline: baseline}
 	e.caretOn = false
 	if e.focused {
 		now := gtx.Now()
@@ -257,21 +247,24 @@ func (e *Editor) layout(gtx *layout.Context, s *Shaper, font Font) {
 		}
 		e.caretOn = e.focused && (!blinking || dt%timePerBlink < timePerBlink/2)
 	}
+
+	gtx.Dimensions = layout.Dimensions{Size: e.viewSize, Baseline: e.dims.Baseline}
 }
 
 func (e *Editor) draw(gtx *layout.Context, s *Shaper, font Font) {
 	var stack op.StackOp
 	stack.Push(gtx.Ops)
 	off := image.Point{
-		X: -e.scrollOff.X + e.padLeft,
+		X: -e.scrollOff.X,
-		Y: -e.scrollOff.Y + e.padTop,
+		Y: -e.scrollOff.Y,
 	}
-	clip := e.clipRect()
+	clip := textPadding(e.lines)
+	clip.Max = clip.Max.Add(e.viewSize)
 	it := lineIterator{
 		Lines:     e.lines,
 		Clip:      clip,
 		Alignment: e.Alignment,
-		Width:     e.viewWidth(),
+		Width:     e.viewSize.X,
 		Offset:    off,
 	}
 	for {
@@ -304,10 +297,20 @@ func (e *Editor) drawCaret(gtx *layout.Context) {
 		Max: image.Point{X: carX.Ceil() + e.carWidth.Ceil(), Y: carY + carDesc.Ceil()},
 	}
 	carRect = carRect.Add(image.Point{
-		X: -e.scrollOff.X + e.padLeft,
+		X: -e.scrollOff.X,
-		Y: -e.scrollOff.Y + e.padTop,
+		Y: -e.scrollOff.Y,
 	})
-	carRect = e.clipRect().Intersect(carRect)
+	clip := textPadding(e.lines)
+	// Account for caret width to each side.
+	whalf := (e.carWidth / 2).Ceil()
+	if clip.Max.X < whalf {
+		clip.Max.X = whalf
+	}
+	if clip.Min.X > -whalf {
+		clip.Min.X = -whalf
+	}
+	clip.Max = clip.Max.Add(e.viewSize)
+	carRect = clip.Intersect(carRect)
 	if !carRect.Empty() {
 		paint.PaintOp{Rect: toRectF(carRect)}.Add(gtx.Ops)
 	}
@@ -331,17 +334,11 @@ func (e *Editor) SetText(s string) {
 	e.prepend(s)
 }
 
-func (e *Editor) clipRect() image.Rectangle {
-	clip := textPadding(e.lines)
-	clip.Max = clip.Max.Add(e.viewSize)
-	return clip
-}
-
 func (e *Editor) scrollBounds() image.Rectangle {
 	var b image.Rectangle
 	if e.SingleLine {
 		if len(e.lines) > 0 {
-			b.Min.X = align(e.Alignment, e.lines[0].Width, e.viewWidth()).Floor()
+			b.Min.X = align(e.Alignment, e.lines[0].Width, e.viewSize.X).Floor()
 			if b.Min.X > 0 {
 				b.Min.X = 0
 			}
@@ -379,12 +376,12 @@ func (e *Editor) moveCoord(c unit.Converter, pos image.Point) {
 	for _, l := range e.lines {
 		y += (prevDesc + l.Ascent).Ceil()
 		prevDesc = l.Descent
-		if y+prevDesc.Ceil() >= pos.Y+e.scrollOff.Y-e.padTop {
+		if y+prevDesc.Ceil() >= pos.Y+e.scrollOff.Y {
 			break
 		}
 		carLine++
 	}
-	x := fixed.I(pos.X + e.scrollOff.X - e.padLeft)
+	x := fixed.I(pos.X + e.scrollOff.X)
 	e.moveToLine(x, carLine)
 }
 
@@ -409,18 +406,9 @@ func (e *Editor) layoutText(c unit.Converter, s *Shaper, font Font) {
 			}
 		}
 	}
-	padTop, padBottom := textPadding(lines)
-	dims.Size.Y += padTop + padBottom
-	dims.Size.X += e.padLeft + e.padRight
-	e.padTop = padTop
-	e.padBottom = padBottom
 	e.lines, e.dims = lines, dims
 }
 
-func (e *Editor) viewWidth() int {
-	return e.viewSize.X - e.padLeft - e.padRight
-}
-
 func (e *Editor) layoutCaret() (carLine, carCol int, x fixed.Int26_6, y int) {
 	e.adjustScroll()
 	var idx int
@@ -446,7 +434,7 @@ loop:
 		}
 		idx += len(l.Text.String)
 	}
-	x += align(e.Alignment, e.lines[carLine].Width, e.viewWidth())
+	x += align(e.Alignment, e.lines[carLine].Width, e.viewSize.X)
 	return
 }
 
@@ -530,7 +518,7 @@ func (e *Editor) moveToLine(carX fixed.Int26_6, carLine2 int) fixed.Int26_6 {
 		}
 	}
 	l2 := e.lines[carLine2]
-	carX2 := align(e.Alignment, l2.Width, e.viewWidth())
+	carX2 := align(e.Alignment, l2.Width, e.viewSize.X)
 	// Only move past the end of the last line
 	end := 0
 	if carLine2 < len(e.lines)-1 {
@@ -587,7 +575,7 @@ func (e *Editor) moveEnd() {
 		e.rr.caret += s
 		x += adv
 	}
-	a := align(e.Alignment, l.Width, e.viewWidth())
+	a := align(e.Alignment, l.Width, e.viewSize.X)
 	e.carXOff = l.Width + a - x
 }
 
@@ -595,21 +583,19 @@ func (e *Editor) scrollToCaret() {
 	carLine, _, x, y := e.layoutCaret()
 	l := e.lines[carLine]
 	if e.SingleLine {
-		minx := (x - e.carWidth/2).Ceil()
+		if d := x.Floor() - e.scrollOff.X; d < 0 {
-		if d := minx - e.scrollOff.X + e.padLeft; d < 0 {
 			e.scrollOff.X += d
 		}
-		maxx := (x + e.carWidth/2).Ceil()
+		if d := x.Ceil() - (e.scrollOff.X + e.viewSize.X); d > 0 {
-		if d := maxx - (e.scrollOff.X + e.viewSize.X - e.padRight); d > 0 {
 			e.scrollOff.X += d
 		}
 	} else {
-		miny := y + l.Bounds.Min.Y.Floor()
+		miny := y - l.Ascent.Ceil()
-		if d := miny - e.scrollOff.Y + e.padTop; d < 0 {
+		if d := miny - e.scrollOff.Y; d < 0 {
 			e.scrollOff.Y += d
 		}
-		maxy := y + l.Bounds.Max.Y.Ceil()
+		maxy := y + l.Descent.Ceil()
-		if d := maxy - (e.scrollOff.Y + e.viewSize.Y - e.padBottom); d > 0 {
+		if d := maxy - (e.scrollOff.Y + e.viewSize.Y); d > 0 {
 			e.scrollOff.Y += d
 		}
 	}