Add color filter blend modes (#2013)

* Add color filter blend modes

* Only show modes supported by currently used API level.

* Fix arrays.xml for API level <=27.

app/src/main/java/eu/kanade/tachiyomi/data/preference/PreferenceKeys.kt

@@ -29,6 +29,8 @@ object PreferenceKeys {
 
     const val colorFilterValue = "color_filter_value"
 
+    const val colorFilterMode = "color_filter_mode"
+
     const val defaultViewer = "pref_default_viewer_key"
 
     const val imageScaleType = "pref_image_scale_type_key"

app/src/main/java/eu/kanade/tachiyomi/data/preference/PreferencesHelper.kt

@@ -57,6 +57,8 @@ class PreferencesHelper(val context: Context) {
 
     fun colorFilterValue() = rxPrefs.getInteger(Keys.colorFilterValue, 0)
 
+    fun colorFilterMode() = rxPrefs.getInteger(Keys.colorFilterMode, 0)
+
     fun defaultViewer() = prefs.getInt(Keys.defaultViewer, 1)
 
     fun imageScaleType() = rxPrefs.getInteger(Keys.imageScaleType, 1)

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

@@ -574,6 +574,9 @@ class ReaderActivity : BaseRxActivity<ReaderPresenter>() {
 
             subscriptions += preferences.colorFilter().asObservable()
                 .subscribe { setColorFilter(it) }
+
+            subscriptions += preferences.colorFilterMode().asObservable()
+                .subscribe { setColorFilter(preferences.colorFilter().getOrDefault()) }
         }
 
         /**
@@ -722,7 +725,7 @@ class ReaderActivity : BaseRxActivity<ReaderPresenter>() {
          */
         private fun setColorFilterValue(value: Int) {
             color_overlay.visibility = View.VISIBLE
-            color_overlay.setBackgroundColor(value)
+            color_overlay.setFilterColor(value, preferences.colorFilterMode().getOrDefault())
         }
 
     }

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

@@ -11,6 +11,7 @@ import eu.kanade.tachiyomi.R
 import eu.kanade.tachiyomi.data.preference.PreferencesHelper
 import eu.kanade.tachiyomi.data.preference.getOrDefault
 import eu.kanade.tachiyomi.util.plusAssign
+import eu.kanade.tachiyomi.widget.IgnoreFirstSpinnerListener
 import eu.kanade.tachiyomi.widget.SimpleSeekBarListener
 import kotlinx.android.synthetic.main.reader_color_filter.*
 import kotlinx.android.synthetic.main.reader_color_filter_sheet.*
@@ -54,6 +55,9 @@ class ReaderColorFilterSheet(activity: ReaderActivity) : BottomSheetDialog(activ
         subscriptions += preferences.colorFilter().asObservable()
             .subscribe { setColorFilter(it, view) }
 
+        subscriptions += preferences.colorFilterMode().asObservable()
+            .subscribe { setColorFilter(preferences.colorFilter().getOrDefault(), view) }
+
         subscriptions += preferences.customBrightness().asObservable()
             .subscribe { setCustomBrightness(it, view) }
 
@@ -84,6 +88,11 @@ class ReaderColorFilterSheet(activity: ReaderActivity) : BottomSheetDialog(activ
             preferences.customBrightness().set(isChecked)
         }
 
+        color_filter_mode.onItemSelectedListener = IgnoreFirstSpinnerListener { position ->
+            preferences.colorFilterMode().set(position)
+        }
+        color_filter_mode.setSelection(preferences.colorFilterMode().getOrDefault(), false)
+
         seekbar_color_filter_alpha.setOnSeekBarChangeListener(object : SimpleSeekBarListener() {
             override fun onProgressChanged(seekBar: SeekBar, value: Int, fromUser: Boolean) {
                 if (fromUser) {
@@ -248,7 +257,7 @@ class ReaderColorFilterSheet(activity: ReaderActivity) : BottomSheetDialog(activ
      */
     private fun setColorFilterValue(@ColorInt color: Int, view: View) = with(view) {
         color_overlay.visibility = View.VISIBLE
-        color_overlay.setBackgroundColor(color)
+        color_overlay.setFilterColor(color, preferences.colorFilterMode().getOrDefault())
         setValues(color, view)
     }
 

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

@@ -0,0 +1,32 @@
+package eu.kanade.tachiyomi.ui.reader
+
+import android.content.Context
+import android.graphics.*
+import android.util.AttributeSet
+import android.view.View
+
+class ReaderColorFilterView(
+        context: Context,
+        attrs: AttributeSet? = null
+) : View(context, attrs) {
+
+    private val colorFilterPaint: Paint = Paint()
+
+    fun setFilterColor(color: Int, filterMode: Int) {
+        colorFilterPaint.setColor(color)
+        colorFilterPaint.xfermode = PorterDuffXfermode(when (filterMode) {
+            1 -> PorterDuff.Mode.MULTIPLY
+            2 -> PorterDuff.Mode.SCREEN
+            3 -> PorterDuff.Mode.OVERLAY
+            4 -> PorterDuff.Mode.LIGHTEN
+            5 -> PorterDuff.Mode.DARKEN
+            else -> PorterDuff.Mode.SRC_OVER
+        })
+        invalidate()
+    }
+
+    override fun onDraw(canvas: Canvas) {
+        super.onDraw(canvas)
+        canvas.drawPaint(colorFilterPaint)
+    }
+}