Fix filename truncation with proper scaling and ellipsis width measurement

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

internal/ui/render.go

@@ -2,6 +2,7 @@ package ui
 
 import (
 	"image"
+	"log"
 
 	"gioui.org/layout"
 	"gioui.org/op"
@@ -92,11 +93,13 @@ func (r *Renderer) drawStatusBar(gtx layout.Context, sb StatusBar) {
 	// Truncate filename only if it doesn't fit
 	displayFilename := sb.Filename
 	availableWidth := int(reg.W - unit.Dp(8) - unit.Dp(40)) // left margin + right icons in DP
-	ellipsisWidth := textWidth(gtx, th.Shaper, "...", r.theme.FontSize)
+	ellipsisWidths := charWidths(gtx, th.Shaper, "...", r.theme.FontSize)
+	ellipsisWidth := ellipsisWidths[len(ellipsisWidths)-1]
 	// Measure how wide "..." is, then find how many chars fit in availableWidth - ellipsisWidth
 	spaceForText := availableWidth - ellipsisWidth
 	widths := charWidths(gtx, th.Shaper, displayFilename, r.theme.FontSize)
-	if len(widths) > 0 && widths[len(widths)-1] > availableWidth {
+	log.Printf("drawStatusBar: filename=%q availableWidth=%d ellipsisWidth=%d spaceForText=%d widths=%v", displayFilename, availableWidth, ellipsisWidth, spaceForText, widths)
+	if len(widths) > 0 && widths[len(widths)-1] > spaceForText {
 		// Find the largest index where the width fits
 		for i, w := range widths {
 			if w <= spaceForText {
@@ -109,6 +112,7 @@ func (r *Renderer) drawStatusBar(gtx layout.Context, sb StatusBar) {
 			}
 		}
 	}
+	log.Printf("drawStatusBar: final filename=%q", displayFilename)
 
 	// Position filename at (reg.X + 8, filenameLineY)
 	call1 := op.Offset(image.Point{X: int(reg.X + unit.Dp(8)), Y: int(filenameLineY)}).Push(gtx.Ops)
@@ -210,38 +214,54 @@ func boolToString(b bool) string {
 
 // textWidth measures the total width of a string using the shaper.
 func textWidth(gtx layout.Context, shp *text.Shaper, str string, size unit.Sp) int {
-	shp.LayoutString(text.Parameters{PxPerEm: 1024}, str)
-	var lastX fixed.Int26_6
+	pixelsPerDp := gtx.Dp(unit.Dp(1))
+	shp.LayoutString(text.Parameters{PxPerEm: fixed.Int26_6(1024 * pixelsPerDp)}, str)
+	var minX, maxX fixed.Int26_6
+	first := true
 	for {
 		g, ok := shp.NextGlyph()
 		if !ok {
 			break
 		}
-		x := g.X + g.Advance
-		if x > lastX {
-			lastX = x
+		if first {
+			minX = g.X
+			maxX = g.X + g.Advance
+			first = false
+		} else {
+			if g.X < minX {
+				minX = g.X
+			}
+			if g.X+g.Advance > maxX {
+				maxX = g.X + g.Advance
+			}
 		}
 	}
-	return int(lastX)
+	return int(maxX - minX)
 }
 
 // charWidths returns the cumulative width after each rune in str.
 func charWidths(gtx layout.Context, shp *text.Shaper, str string, size unit.Sp) []int {
-	shp.LayoutString(text.Parameters{PxPerEm: 1024}, str)
-	var widths []int
-	var cumX fixed.Int26_6
+	pixelsPerDp := gtx.Dp(unit.Dp(1))
+	shp.LayoutString(text.Parameters{PxPerEm: fixed.Int26_6(1024 * pixelsPerDp)}, str)
+	var runeAdvances []fixed.Int26_6
 	var runeIdx int
 	for {
 		g, ok := shp.NextGlyph()
 		if !ok {
 			break
 		}
-		cumX = g.X + g.Advance
-		// Each glyph corresponds to one rune in our simple ASCII case
 		if runeIdx < len(str) {
-			widths = append(widths, int(cumX))
+			runeAdvances = append(runeAdvances, g.Advance)
 			runeIdx++
 		}
 	}
+	// Accumulate advances and convert from Int26_6 to int (divide by 64)
+	var widths []int
+	var cumWidth fixed.Int26_6
+	for _, adv := range runeAdvances {
+		cumWidth += adv
+		widths = append(widths, int(cumWidth>>6))
+	}
+	log.Printf("charWidths: runeAdvances=%v widths=%v", runeAdvances, widths)
 	return widths
 }