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

@@ -42,7 +42,7 @@ type Editor struct {
 	Submit bool
 
 	scale        int
-	font              editorFont
+	font         Font
 	blinkStart   time.Time
 	focused      bool
 	rr           editBuffer
@@ -51,8 +51,6 @@ type Editor struct {
 	valid        bool
 	lines        []Line
 	dims         layout.Dimensions
-	padTop, padBottom int
-	padLeft, padRight int
 	carWidth     fixed.Int26_6
 	requestFocus bool
 	caretOn      bool
@@ -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
 		}
 	}