From 39c0b7425070d2dd86d543eafdfb72e7a94a6a99 Mon Sep 17 00:00:00 2001
From: arkon <eugcheung94@gmail.com>
Date: Fri, 6 May 2022 23:10:56 -0400
Subject: [PATCH] Fix tall image split math issues

- Round up per-split height to ensure the entire page ends up being split
- Handle the last split of a page potentially being shorter than the others
---
 .../kanade/tachiyomi/data/download/Downloader.kt  | 15 ++++++++++-----
 .../ui/reader/viewer/pager/PagerPageHolder.kt     |  3 ++-
 .../ui/reader/viewer/webtoon/WebtoonPageHolder.kt |  3 ++-
 .../eu/kanade/tachiyomi/util/system/ImageUtil.kt  |  3 ++-
 4 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/app/src/main/java/eu/kanade/tachiyomi/data/download/Downloader.kt b/app/src/main/java/eu/kanade/tachiyomi/data/download/Downloader.kt
index dafce33e7..b4535cfde 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/data/download/Downloader.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/data/download/Downloader.kt
@@ -46,6 +46,8 @@ import java.io.FileOutputStream
 import java.util.zip.CRC32
 import java.util.zip.ZipEntry
 import java.util.zip.ZipOutputStream
+import kotlin.math.ceil
+import kotlin.math.min
 
 /**
  * This class is the one in charge of downloading chapters.
@@ -569,25 +571,28 @@ class Downloader(
 
         val bitmap = BitmapFactory.decodeFile(imageFile.filePath)
         val splitsCount = bitmap.height / context.resources.displayMetrics.heightPixels + 1
-        val heightPerSplit = bitmap.height / splitsCount
+        val heightPerSplit = ceil(bitmap.height / splitsCount.toDouble()).toInt()
+        logcat { "Splitting height ${bitmap.height} by $splitsCount * $heightPerSplit" }
 
         try {
-            (0..splitsCount).forEach { split ->
+            (0 until splitsCount).forEach { split ->
+                logcat { "Split #$split at y=${split * heightPerSplit}" }
                 val splitPath = imageFile.filePath!!.substringBeforeLast(".") + "__${"%03d".format(split + 1)}.jpg"
+                val splitHeight = split * heightPerSplit
                 FileOutputStream(splitPath).use { stream ->
                     Bitmap.createBitmap(
                         bitmap,
                         0,
-                        split * heightPerSplit,
+                        splitHeight,
                         bitmap.width,
-                        heightPerSplit,
+                        min(heightPerSplit, bitmap.height - splitHeight),
                     ).compress(Bitmap.CompressFormat.JPEG, 100, stream)
                 }
             }
             imageFile.delete()
         } catch (e: Exception) {
             // Image splits were not successfully saved so delete them and keep the original image
-            (0..splitsCount)
+            (0 until splitsCount)
                 .map { imageFile.filePath!!.substringBeforeLast(".") + "__${"%03d".format(it + 1)}.jpg" }
                 .forEach { File(it).delete() }
             throw e
diff --git a/app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/pager/PagerPageHolder.kt b/app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/pager/PagerPageHolder.kt
index 408b0263c..694c47da6 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/pager/PagerPageHolder.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/pager/PagerPageHolder.kt
@@ -19,6 +19,7 @@ import rx.Observable
 import rx.Subscription
 import rx.android.schedulers.AndroidSchedulers
 import rx.schedulers.Schedulers
+import java.io.BufferedInputStream
 import java.io.ByteArrayInputStream
 import java.io.InputStream
 import java.util.concurrent.TimeUnit
@@ -238,7 +239,7 @@ class PagerPageHolder(
             .subscribe({}, {})
     }
 
-    private fun process(page: ReaderPage, imageStream: InputStream): InputStream {
+    private fun process(page: ReaderPage, imageStream: BufferedInputStream): InputStream {
         if (!viewer.config.dualPageSplit) {
             return imageStream
         }
diff --git a/app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/webtoon/WebtoonPageHolder.kt b/app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/webtoon/WebtoonPageHolder.kt
index ebeef9ecf..3463eafd6 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/webtoon/WebtoonPageHolder.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/webtoon/WebtoonPageHolder.kt
@@ -23,6 +23,7 @@ import rx.Observable
 import rx.Subscription
 import rx.android.schedulers.AndroidSchedulers
 import rx.schedulers.Schedulers
+import java.io.BufferedInputStream
 import java.io.InputStream
 import java.util.concurrent.TimeUnit
 
@@ -272,7 +273,7 @@ class WebtoonPageHolder(
         addSubscription(readImageHeaderSubscription)
     }
 
-    private fun process(imageStream: InputStream): InputStream {
+    private fun process(imageStream: BufferedInputStream): InputStream {
         if (!viewer.config.dualPageSplit) {
             return imageStream
         }
diff --git a/app/src/main/java/eu/kanade/tachiyomi/util/system/ImageUtil.kt b/app/src/main/java/eu/kanade/tachiyomi/util/system/ImageUtil.kt
index f634dd5d2..a596600aa 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/util/system/ImageUtil.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/util/system/ImageUtil.kt
@@ -18,6 +18,7 @@ import androidx.core.graphics.green
 import androidx.core.graphics.red
 import tachiyomi.decoder.Format
 import tachiyomi.decoder.ImageDecoder
+import java.io.BufferedInputStream
 import java.io.ByteArrayInputStream
 import java.io.ByteArrayOutputStream
 import java.io.InputStream
@@ -103,7 +104,7 @@ object ImageUtil {
      *
      * @return true if the width is greater than the height
      */
-    fun isWideImage(imageStream: InputStream): Boolean {
+    fun isWideImage(imageStream: BufferedInputStream): Boolean {
         val options = extractImageOptions(imageStream)
         imageStream.reset()
         return options.outWidth > options.outHeight