From 75d744ab8d81ef00eb2a0b5b0f58bf45030913d1 Mon Sep 17 00:00:00 2001
From: Chris Waldon <christopher.waldon.dev@gmail.com>
Date: Mon, 21 Nov 2022 14:31:40 -0500
Subject: [PATCH] styledtext: [WIP] adapt to new text shaping APIs

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
---
 styledtext/styledtext.go | 31 +++++++++++++++++++------------
 1 file changed, 19 insertions(+), 12 deletions(-)

diff --git a/styledtext/styledtext.go b/styledtext/styledtext.go
index 3de2e64..a92e04b 100644
--- a/styledtext/styledtext.go
+++ b/styledtext/styledtext.go
@@ -37,10 +37,7 @@ type spanShape struct {
 func (ss SpanStyle) Layout(gtx layout.Context, s text.Shaper, shape spanShape) layout.Dimensions {
 	paint.ColorOp{Color: ss.Color}.Add(gtx.Ops)
 	defer op.Offset(shape.offset).Push(gtx.Ops).Pop()
-	left := text.GlyphPosition{}
-	right := text.GlyphPosition{Run: len(shape.layout.Runs) - 1}
-	right.Glyph = len(shape.layout.Runs[right.Run].Glyphs) - 1
-	defer clip.Outline{Path: s.Shape(shape.layout, left, right)}.Op().Push(gtx.Ops).Pop()
+	defer clip.Outline{Path: s.Shape(shape.layout)}.Op().Push(gtx.Ops).Pop()
 	paint.PaintOp{}.Add(gtx.Ops)
 	return layout.Dimensions{Size: shape.size}
 }
@@ -93,13 +90,23 @@ func (t TextStyle) Layout(gtx layout.Context, spanFn func(gtx layout.Context, id
 		maxWidth := gtx.Constraints.Max.X - lineDims.X
 
 		// shape the text of the current span
-		lines := t.Shaper.LayoutString(span.Font, fixed.I(gtx.Sp(span.Size)), maxWidth, gtx.Locale, span.Content)
+		shaped := t.Shaper.LayoutString(text.Parameters{
+			Font:    span.Font,
+			PxPerEm: fixed.I(gtx.Sp(span.Size)),
+		}, 0, maxWidth, gtx.Locale, span.Content)
+
+		shaped.SetViewport(image.Rectangle{Max: image.Pt(1e6, 1e6)})
 
 		// grab the first line of the result and compute its dimensions
-		firstLine := lines[0]
-		spanWidth := firstLine.Width.Ceil()
-		spanHeight := (firstLine.Ascent + firstLine.Descent).Ceil()
-		spanAscent := firstLine.Ascent.Ceil()
+		firstLine, ok := shaped.Next()
+		if !ok {
+			continue
+		}
+		width, ascent, descent := firstLine.Metrics()
+		_, multiLine := shaped.Next()
+		spanWidth := width.Ceil()
+		spanHeight := (ascent + descent).Ceil()
+		spanAscent := ascent.Ceil()
 
 		// forceToNextLine handles the case in which the first segment of the new span does not fit
 		// AND there is already content on the current line. If there is no content on the line,
@@ -133,7 +140,7 @@ func (t TextStyle) Layout(gtx layout.Context, spanFn func(gtx layout.Context, id
 
 		// if we are breaking the current span across lines or we are on the
 		// last span, lay out all of the spans for the line.
-		if len(lines) > 1 || i == len(spans)-1 || forceToNextLine {
+		if multiLine || i == len(spans)-1 || forceToNextLine {
 			lineMacro := op.Record(gtx.Ops)
 			for i, shape := range lineShapes {
 				// lay out this span
@@ -181,7 +188,7 @@ func (t TextStyle) Layout(gtx layout.Context, spanFn func(gtx layout.Context, id
 		}
 
 		// if the current span breaks across lines
-		if len(lines) > 1 && !forceToNextLine {
+		if multiLine && !forceToNextLine {
 			// mark where the next line to be laid out starts
 			lineStartIndex = i + 1
 			lineDims = image.Point{}
@@ -195,7 +202,7 @@ func (t TextStyle) Layout(gtx layout.Context, spanFn func(gtx layout.Context, id
 			}
 			// synthesize and insert a new span
 			byteLen := 0
-			for i := 0; i < firstLine.RuneCount; i++ {
+			for i := 0; i < firstLine.Runes(); i++ {
 				_, n := utf8.DecodeRuneInString(span.Content[byteLen:])
 				byteLen += n
 			}
-- 
2.45.2