Automatic Reader Background

app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderActivity.kt

@@ -110,8 +110,8 @@ class ReaderActivity : BaseRxActivity<ReaderPresenter>() {
      */
     override fun onCreate(savedState: Bundle?) {
         setTheme(when (preferences.readerTheme().getOrDefault()) {
-            0 -> R.style.Theme_Reader_Light
+            1 -> R.style.Theme_Reader
-            else -> R.style.Theme_Reader
+            else -> R.style.Theme_Reader_Light
         })
         super.onCreate(savedState)
         setContentView(R.layout.reader_activity)

app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/pager/PagerPageHolder.kt

@@ -2,6 +2,7 @@ package eu.kanade.tachiyomi.ui.reader.viewer.pager
 
 import android.annotation.SuppressLint
 import android.content.Intent
+import android.graphics.BitmapFactory
 import android.graphics.PointF
 import android.graphics.drawable.Drawable
 import android.net.Uri
@@ -27,19 +28,19 @@ import com.davemorrissey.labs.subscaleview.SubsamplingScaleImageView
 import com.github.chrisbanes.photoview.PhotoView
 import eu.kanade.tachiyomi.R
 import eu.kanade.tachiyomi.data.glide.GlideApp
+import eu.kanade.tachiyomi.data.preference.PreferencesHelper
 import eu.kanade.tachiyomi.source.model.Page
 import eu.kanade.tachiyomi.ui.reader.model.ReaderPage
 import eu.kanade.tachiyomi.ui.reader.viewer.ReaderProgressBar
 import eu.kanade.tachiyomi.ui.reader.viewer.pager.PagerConfig.ZoomType
-import eu.kanade.tachiyomi.util.ImageUtil
+import eu.kanade.tachiyomi.util.*
-import eu.kanade.tachiyomi.util.dpToPx
-import eu.kanade.tachiyomi.util.gone
-import eu.kanade.tachiyomi.util.visible
 import eu.kanade.tachiyomi.widget.ViewPagerAdapter
+import kotlinx.coroutines.experimental.async
 import rx.Observable
 import rx.Subscription
 import rx.android.schedulers.AndroidSchedulers
 import rx.schedulers.Schedulers
+import uy.kohesive.injekt.injectLazy
 import java.io.InputStream
 import java.util.concurrent.TimeUnit
 
@@ -99,6 +100,8 @@ class PagerPageHolder(
      */
     private var readImageHeaderSubscription: Subscription? = null
 
+    private val preferences by injectLazy<PreferencesHelper>()
+
     init {
         addView(progressBar)
         observeStatus()
@@ -243,7 +246,22 @@ class PagerPageHolder(
             .observeOn(AndroidSchedulers.mainThread())
             .doOnNext { isAnimated ->
                 if (!isAnimated) {
-                    initSubsamplingImageView().setImage(ImageSource.inputStream(openStream!!))
+                    if (preferences.readerTheme().get() == 2) {
+                        val bytesArray = openStream!!.readBytes()
+
+                        val imageView = initSubsamplingImageView()
+                        val bytesStream = bytesArray.inputStream()
+                        imageView.setImage(ImageSource.inputStream(bytesStream))
+
+                        launchUI {
+                            val backgroundD = async { ImageUtil.autoSetBackground(BitmapFactory.decodeByteArray(bytesArray, 0, bytesArray.size)) }
+                            imageView.background = backgroundD.await()
+                        }
+                        bytesStream.close()
+                    }
+                    else {
+                        initSubsamplingImageView().setImage(ImageSource.inputStream(openStream!!))
+                    }
                 } else {
                     initImageView().setImage(openStream!!)
                 }

app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsReaderController.kt

@@ -49,8 +49,8 @@ class SettingsReaderController : SettingsController() {
         intListPreference {
             key = Keys.readerTheme
             titleRes = R.string.pref_reader_theme
-            entriesRes = arrayOf(R.string.white_background, R.string.black_background)
+            entriesRes = arrayOf(R.string.white_background, R.string.black_background, R.string.auto_background)
-            entryValues = arrayOf("0", "1")
+            entryValues = arrayOf("0", "1", "2")
             defaultValue = "0"
             summary = "%s"
         }

app/src/main/java/eu/kanade/tachiyomi/util/ImageUtil.kt

@@ -1,5 +1,8 @@
 package eu.kanade.tachiyomi.util
 
+import android.graphics.Bitmap
+import android.graphics.Color
+import android.graphics.drawable.*
 import java.io.InputStream
 import java.net.URLConnection
 
@@ -49,6 +52,90 @@ object ImageUtil {
         return null
     }
 
+    fun autoSetBackground(image: Bitmap): Drawable {
+        if (image.width < 50 || image.height < 50)
+            return ColorDrawable(Color.WHITE)
+        val topLeftIsDark = isDark(image.getPixel(2,2))
+        val topRightIsDark = isDark(image.getPixel(image.width - 2,2))
+        val midLeftIsDark = isDark(image.getPixel(2,image.height/2))
+        val midRightIsDark = isDark(image.getPixel(image.width - 2,image.height/2))
+        val topMidIsDark = isDark(image.getPixel(image.width/2, 2))
+        val botLeftIsDark = isDark(image.getPixel(2,image.height - 2))
+        val botRightIsDark = isDark(image.getPixel(image.width - 2,image.height - 2))
+
+        var darkBG = (topLeftIsDark && (botLeftIsDark || botRightIsDark || topRightIsDark || midLeftIsDark || topMidIsDark))
+                || (topRightIsDark && (botRightIsDark || botLeftIsDark || midRightIsDark || topMidIsDark))
+        if (darkBG) {
+            if (isWhite(image.getPixel(2,2)).toInt() +
+                    isWhite(image.getPixel(image.width - 2,2)).toInt() +
+                    isWhite(image.getPixel(2,image.height - 2)).toInt() +
+                    isWhite(image.getPixel(image.width - 2,image.height - 2)).toInt() > 2)
+                darkBG = false
+            var overallWhitePixels = 0
+            var overallBlackPixels = 0
+            outer@ for (x in intArrayOf(2,image.width-2)) {
+                var whitePixelsStreak = 0
+                var whitePixels = 0
+                var blackPixelsStreak = 0
+                var blackPixels = 0
+                var blackStreak = false
+                var whiteStrak = false
+                for (y in (0 until image.height step image.height / 25)) {
+                    val pixel = image.getPixel(x, y)
+                    if (isWhite(pixel)) {
+                        blackPixelsStreak = 0
+                        whitePixelsStreak++
+                        whitePixels++
+                        overallWhitePixels++
+                        if (whitePixelsStreak > 14) {
+                            whiteStrak = true
+                        }
+                    }
+                    else {
+                        whitePixelsStreak = 0
+                        if (isDark(pixel)) {
+                            blackPixels++
+                            overallBlackPixels++
+                            blackPixelsStreak++
+                            if (blackPixelsStreak > 14) {
+                                blackStreak = true
+                            }
+                        }
+                        else {
+                            blackPixelsStreak = 0
+                        }
+                    }
+                }
+                when {
+                    blackPixels > 22 -> return ColorDrawable(Color.BLACK)
+                    blackStreak -> darkBG = true
+                    whiteStrak || whitePixels > 22 -> darkBG = false
+                }
+            }
+            if (overallWhitePixels > 9 && overallWhitePixels >= overallBlackPixels)
+                darkBG = false
+        }
+        if (darkBG)
+        {
+            if (isWhite(image.getPixel(2,image.height - 2)) && isWhite(image.getPixel(image.width - 2,image.height - 2)))
+                return GradientDrawable(GradientDrawable.Orientation.TOP_BOTTOM,
+                        intArrayOf(Color.BLACK, Color.BLACK, Color.WHITE, Color.WHITE))
+            else
+                return ColorDrawable(Color.BLACK)
+        }
+        return ColorDrawable(Color.WHITE)
+    }
+
+    fun Boolean.toInt() = if (this) 1 else 0
+    private fun isDark(color: Int): Boolean {
+        return Color.red(color) < 33 && Color.blue(color) < 33 && Color.green(color) < 33
+    }
+
+
+    private fun isWhite(color: Int): Boolean {
+        return Color.red(color) + Color.blue(color) + Color.green(color) > 740
+    }
+
     private fun ByteArray.compareWith(magic: ByteArray): Boolean {
         for (i in 0 until magic.size) {
             if (this[i] != magic[i]) return false

app/src/main/res/values/arrays.xml

@@ -25,6 +25,7 @@
     <string-array name="reader_themes">
         <item>@string/white_background</item>
         <item>@string/black_background</item>
+        <item>@string/auto_background</item>
     </string-array>
 
     <string-array name="reader_themes_values">

app/src/main/res/values/strings.xml

@@ -185,6 +185,7 @@
     <string name="pref_reader_theme">Background color</string>
     <string name="white_background">White</string>
     <string name="black_background">Black</string>
+    <string name="auto_background">Automatic</string>
     <string name="pref_viewer_type">Default viewer</string>
     <string name="default_viewer">Default</string>
     <string name="left_to_right_viewer">Left to right</string>