优化

app/src/main/java/io/legado/app/ui/book/read/page/entities/TextLine.kt

@@ -5,7 +5,6 @@ import android.graphics.Canvas
 import android.graphics.Paint.FontMetrics
 import android.os.Build
 import androidx.annotation.Keep
-import androidx.core.graphics.withTranslation
 import io.legado.app.help.PaintPool
 import io.legado.app.help.book.isImage
 import io.legado.app.help.config.AppConfig
@@ -183,19 +182,16 @@ data class TextLine(
         }
         val paint = PaintPool.obtain()
         paint.set(textPaint)
+        val letterSpacing = paint.letterSpacing * paint.textSize
+        val letterSpacingHalf = letterSpacing * 0.5f
         if (extraLetterSpacing != 0f) {
             paint.letterSpacing += extraLetterSpacing
         }
         if (wordSpacing != 0f) {
             paint.wordSpacing = wordSpacing
         }
-        if (extraLetterSpacingOffsetX != 0f) {
-            canvas.withTranslation(extraLetterSpacingOffsetX) {
-                canvas.drawText(text, indentSize, text.length, startX, lineBase - lineTop, paint)
-            }
-        } else {
-            canvas.drawText(text, indentSize, text.length, startX, lineBase - lineTop, paint)
-        }
+        val offsetX = if (atLeastApi35) letterSpacingHalf else extraLetterSpacingOffsetX
+        canvas.drawText(text, indentSize, text.length, startX + offsetX, lineBase - lineTop, paint)
         PaintPool.recycle(paint)
         for (i in columns.indices) {
             val column = columns[i] as TextColumn
@@ -246,6 +242,7 @@ data class TextLine(
     companion object {
         val emptyTextLine = TextLine()
         private val atLeastApi26 = Build.VERSION.SDK_INT >= Build.VERSION_CODES.O
+        private val atLeastApi35 = Build.VERSION.SDK_INT >= Build.VERSION_CODES.VANILLA_ICE_CREAM
         private val wordSpacingWorking by lazy {
             // issue 3785 3846
             val paint = PaintPool.obtain()

app/src/main/java/io/legado/app/ui/book/read/page/entities/TextPage.kt

@@ -2,6 +2,7 @@ package io.legado.app.ui.book.read.page.entities
 
 import android.graphics.Canvas
 import android.graphics.Paint
+import android.os.Build
 import android.text.Layout
 import android.text.StaticLayout
 import androidx.annotation.Keep
@@ -142,10 +143,12 @@ data class TextPage(
         if (isMsgPage && ChapterProvider.viewWidth > 0) {
             textLines.clear()
             val visibleWidth = ChapterProvider.visibleRight - ChapterProvider.paddingLeft
+            val paint = ChapterProvider.contentPaint
             val layout = StaticLayout(
-                text, ChapterProvider.contentPaint, visibleWidth,
+                text, paint, visibleWidth,
                 Layout.Alignment.ALIGN_NORMAL, 1f, 0f, false
             )
+            val letterSpacing = paint.letterSpacing * paint.textSize
             var y = (ChapterProvider.visibleHeight - layout.height) / 2f
             if (y < 0) y = 0f
             for (lineIndex in 0 until layout.lineCount) {
@@ -161,7 +164,10 @@ data class TextPage(
                     text.substring(layout.getLineStart(lineIndex), layout.getLineEnd(lineIndex))
                 for (i in textLine.text.indices) {
                     val char = textLine.text[i].toString()
-                    val cw = StaticLayout.getDesiredWidth(char, ChapterProvider.contentPaint)
+                    var cw = StaticLayout.getDesiredWidth(char, paint)
+                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.VANILLA_ICE_CREAM) {
+                        cw += letterSpacing
+                    }
                     val x1 = x + cw
                     textLine.addColumn(
                         TextColumn(start = x, end = x1, char)

app/src/main/java/io/legado/app/ui/book/read/page/entities/column/TextColumn.kt

@@ -1,6 +1,7 @@
 package io.legado.app.ui.book.read.page.entities.column
 
 import android.graphics.Canvas
+import android.os.Build
 import androidx.annotation.Keep
 import io.legado.app.help.config.ReadBookConfig
 import io.legado.app.lib.theme.ThemeStore
@@ -55,7 +56,14 @@ data class TextColumn(
         if (textPaint.color != textColor) {
             textPaint.color = textColor
         }
-        canvas.drawText(charData, start, textLine.lineBase - textLine.lineTop, textPaint)
+        val y = textLine.lineBase - textLine.lineTop
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.VANILLA_ICE_CREAM) {
+            val letterSpacing = textPaint.letterSpacing * textPaint.textSize
+            val letterSpacingHalf = letterSpacing * 0.5f
+            canvas.drawText(charData, start + letterSpacingHalf, y, textPaint)
+        } else {
+            canvas.drawText(charData, start, y, textPaint)
+        }
         if (selected) {
             canvas.drawRect(start, 0f, end, textLine.height, view.selectedPaint)
         }

app/src/main/java/io/legado/app/ui/book/read/page/provider/TextChapterLayout.kt

@@ -1,6 +1,7 @@
 package io.legado.app.ui.book.read.page.provider
 
 import android.graphics.Paint
+import android.os.Build
 import android.text.Layout
 import android.text.StaticLayout
 import android.text.TextPaint
@@ -416,6 +417,14 @@ class TextChapterLayout(
         var absStartX = x
         val widthsArray = FloatArray(text.length)
         textPaint.getTextWidths(text, widthsArray)
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.VANILLA_ICE_CREAM) {
+            if (widthsArray.isNotEmpty()) {
+                val letterSpacing = textPaint.letterSpacing * textPaint.textSize
+                val letterSpacingHalf = letterSpacing * 0.5f
+                widthsArray[0] += letterSpacingHalf
+                widthsArray[widthsArray.lastIndex] += letterSpacingHalf
+            }
+        }
         val layout = if (ReadBookConfig.useZhLayout) {
             val (words, widths) = measureTextSplit(text, widthsArray)
             ZhLayout(text, textPaint, visibleWidth, words, widths)