feat: 优化代码

app/src/main/java/io/legado/app/help/ReadBookConfig.kt

@@ -27,6 +27,7 @@ object ReadBookConfig {
     val durConfig get() = getConfig(styleSelect)
     private val shareConfig get() = getConfig(5)
     var bg: Drawable? = null
+    var bgMeanColor: Int = 0
 
     init {
         upConfig()
@@ -68,6 +69,13 @@ object ReadBookConfig {
         val width = dm.widthPixels
         val height = dm.heightPixels
         bg = durConfig.bgDrawable(width, height)
+        bg?.let {
+            if (it is BitmapDrawable) {
+                bgMeanColor = BitmapUtils.getMeanColor(it.bitmap)
+            } else if (it is ColorDrawable) {
+                bgMeanColor = it.color
+            }
+        }
     }
 
     fun save() {

app/src/main/java/io/legado/app/ui/book/read/page/delegate/SimulationPageDelegate.kt

@@ -3,6 +3,7 @@ package io.legado.app.ui.book.read.page.delegate
 import android.graphics.*
 import android.graphics.drawable.GradientDrawable
 import android.os.Build
+import io.legado.app.help.ReadBookConfig
 import io.legado.app.ui.book.read.page.PageView
 import kotlin.math.*
 
@@ -268,6 +269,7 @@ class SimulationPageDelegate(pageView: PageView) : HorizontalPageDelegate(pageVi
         mMatrix.setValues(mMatrixArray)
         mMatrix.preTranslate(-mBezierControl1.x, -mBezierControl1.y)
         mMatrix.postTranslate(mBezierControl1.x, mBezierControl1.y)
+        canvas.drawColor(ReadBookConfig.bgMeanColor)
         canvas.drawBitmap(bitmap, mMatrix, mPaint)
         mPaint.colorFilter = null
         canvas.rotate(mDegrees, mBezierStart1.x, mBezierStart1.y)

app/src/main/java/io/legado/app/utils/BitmapUtils.kt

@@ -5,6 +5,7 @@ import android.graphics.Bitmap
 import android.graphics.Bitmap.Config
 import android.graphics.BitmapFactory
 import android.graphics.Canvas
+import android.graphics.Color
 import android.renderscript.Allocation
 import android.renderscript.Element
 import android.renderscript.RenderScript
@@ -12,10 +13,7 @@ import android.renderscript.ScriptIntrinsicBlur
 import android.view.View
 import io.legado.app.App
 import java.io.IOException
-import kotlin.math.ceil
-import kotlin.math.floor
-import kotlin.math.min
-import kotlin.math.sqrt
+import kotlin.math.*
 
 
 @Suppress("unused", "WeakerAccess")
@@ -257,4 +255,31 @@ object BitmapUtils {
         return blurredBitmap
     }
 
+    fun getMeanColor(bitmap: Bitmap): Int {
+        val width: Int = bitmap.width
+        val height: Int = bitmap.height
+        var pixel: Int
+        var pixelSumRed = 0
+        var pixelSumBlue = 0
+        var pixelSumGreen = 0
+        for (i in 0..99) {
+            for (j in 70..99) {
+                pixel = bitmap.getPixel(
+                    (i * width / 100.toFloat()).roundToInt(),
+                    (j * height / 100.toFloat()).roundToInt()
+                )
+                pixelSumRed += Color.red(pixel)
+                pixelSumGreen += Color.green(pixel)
+                pixelSumBlue += Color.blue(pixel)
+            }
+        }
+        val averagePixelRed = pixelSumRed / 3000
+        val averagePixelBlue = pixelSumBlue / 3000
+        val averagePixelGreen = pixelSumGreen / 3000
+        return Color.rgb(
+            averagePixelRed + 3,
+            averagePixelGreen + 3, averagePixelBlue + 3
+        )
+    }
+
 }