implement basic methods for descrambling images

app/src/main/kotlin/org/koitharu/kotatsu/core/parser/BitmapImpl.kt

@@ -0,0 +1,48 @@
+package org.koitharu.kotatsu.core.parser
+
+import android.graphics.Canvas
+import android.graphics.Bitmap as AndroidBitmap
+import android.graphics.Rect as AndroidRect
+import org.koitharu.kotatsu.parsers.bitmap.Bitmap
+import org.koitharu.kotatsu.parsers.bitmap.Rect
+
+class BitmapImpl private constructor() : Bitmap {
+
+	lateinit var androidBitmap: AndroidBitmap
+
+	private lateinit var canvas: Canvas
+
+	override val height: Int
+		get() = androidBitmap.height
+
+	override val width: Int
+		get() = androidBitmap.width
+
+	override fun drawBitmap(sourceBitmap: Bitmap, src: Rect, dst: Rect) {
+		val androidSourceBitmap = (sourceBitmap as BitmapImpl).androidBitmap
+
+		canvas.drawBitmap(androidSourceBitmap, src.toAndroidRect(), dst.toAndroidRect(), null)
+	}
+
+	companion object {
+		fun create(width: Int, height: Int): Bitmap {
+			val instance = BitmapImpl()
+			instance.androidBitmap = AndroidBitmap.createBitmap(width, height, AndroidBitmap.Config.ARGB_8888)
+			instance.canvas = Canvas(instance.androidBitmap)
+
+			return instance
+		}
+
+		fun create(bitmap: AndroidBitmap): Bitmap {
+			val instance = BitmapImpl()
+			instance.androidBitmap = bitmap.copy(AndroidBitmap.Config.ARGB_8888, true)
+			instance.canvas = Canvas(instance.androidBitmap)
+
+			return instance
+		}
+	}
+}
+
+private fun Rect.toAndroidRect(): AndroidRect {
+	return AndroidRect(left, top, right, bottom)
+}