Grayscale color filter

app/src/main/kotlin/org/koitharu/kotatsu/reader/domain/ReaderColorFilter.kt

@@ -7,13 +7,17 @@ data class ReaderColorFilter(
 	val brightness: Float,
 	val contrast: Float,
 	val isInverted: Boolean,
+	val isGrayscale: Boolean,
 ) {
 
 	val isEmpty: Boolean
-		get() = !isInverted && brightness == 0f && contrast == 0f
+		get() = !isGrayscale && !isInverted && brightness == 0f && contrast == 0f
 
 	fun toColorFilter(): ColorMatrixColorFilter {
 		val cm = ColorMatrix()
+		if (isGrayscale) {
+			cm.grayscale()
+		}
 		if (isInverted) {
 			cm.inverted()
 		}
@@ -49,6 +53,20 @@ data class ReaderColorFilter(
 			0.0f, 0.0f, -1.0f, 1.0f, 1.0f,
 			0.0f, 0.0f, 0.0f, 1.0f, 0.0f,
 		)
-		set(matrix)
+		postConcat(ColorMatrix(matrix))
+	}
+
+	private fun ColorMatrix.grayscale() {
+		setSaturation(0f)
+	}
+
+	companion object {
+
+		val EMPTY = ReaderColorFilter(
+			brightness = 0.0f,
+			contrast = 0.0f,
+			isInverted = false,
+			isGrayscale = false,
+		)
 	}
 }

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/colorfilter/ColorFilterConfigActivity.kt

@@ -16,6 +16,7 @@ import coil.ImageLoader
 import coil.request.ImageRequest
 import coil.size.Scale
 import coil.size.ViewSizeResolver
+import com.google.android.material.dialog.MaterialAlertDialogBuilder
 import com.google.android.material.slider.LabelFormatter
 import com.google.android.material.slider.Slider
 import dagger.hilt.android.AndroidEntryPoint
@@ -62,6 +63,7 @@ class ColorFilterConfigActivity :
 		viewBinding.sliderContrast.setLabelFormatter(formatter)
 		viewBinding.sliderBrightness.setLabelFormatter(formatter)
 		viewBinding.switchInvert.setOnCheckedChangeListener(this)
+		viewBinding.switchGrayscale.setOnCheckedChangeListener(this)
 		viewBinding.buttonDone.setOnClickListener(this)
 		viewBinding.buttonReset.setOnClickListener(this)
 
@@ -84,18 +86,16 @@ class ColorFilterConfigActivity :
 		}
 	}
 
-	override fun onCheckedChanged(buttonView: CompoundButton?, isChecked: Boolean) {
-		viewModel.setInversion(isChecked)
+	override fun onCheckedChanged(buttonView: CompoundButton, isChecked: Boolean) {
+		when (buttonView.id) {
+			R.id.switch_invert -> viewModel.setInversion(isChecked)
+			R.id.switch_grayscale -> viewModel.setGrayscale(isChecked)
+		}
 	}
 
 	override fun onClick(v: View) {
 		when (v.id) {
-			R.id.button_done -> if (viewBinding.checkBoxGlobal.isChecked) {
-				viewModel.saveGlobally()
-			} else {
-				viewModel.save()
-			}
-
+			R.id.button_done -> showSaveConfirmation()
 			R.id.button_reset -> viewModel.reset()
 		}
 	}
@@ -113,10 +113,23 @@ class ColorFilterConfigActivity :
 		}
 	}
 
+	fun showSaveConfirmation() {
+		MaterialAlertDialogBuilder(this)
+			.setTitle(R.string.apply)
+			.setMessage(R.string.color_correction_apply_text)
+			.setNegativeButton(android.R.string.cancel, null)
+			.setPositiveButton(R.string.this_manga) { _, _ ->
+				viewModel.saveGlobally()
+			}.setNeutralButton(R.string.globally) { _, _ ->
+				viewModel.save()
+			}.show()
+	}
+
 	private fun onColorFilterChanged(readerColorFilter: ReaderColorFilter?) {
 		viewBinding.sliderBrightness.setValueRounded(readerColorFilter?.brightness ?: 0f)
 		viewBinding.sliderContrast.setValueRounded(readerColorFilter?.contrast ?: 0f)
 		viewBinding.switchInvert.setChecked(readerColorFilter?.isInverted ?: false, false)
+		viewBinding.switchGrayscale.setChecked(readerColorFilter?.isGrayscale ?: false, false)
 		viewBinding.imageViewAfter.colorFilter = readerColorFilter?.toColorFilter()
 	}
 
@@ -138,6 +151,8 @@ class ColorFilterConfigActivity :
 	private fun onLoadingChanged(isLoading: Boolean) {
 		viewBinding.sliderContrast.isEnabled = !isLoading
 		viewBinding.sliderBrightness.isEnabled = !isLoading
+		viewBinding.switchInvert.isEnabled = !isLoading
+		viewBinding.switchGrayscale.isEnabled = !isLoading
 		viewBinding.buttonDone.isEnabled = !isLoading
 	}
 

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/colorfilter/ColorFilterConfigBackPressedDispatcher.kt

@@ -1,6 +1,5 @@
 package org.koitharu.kotatsu.reader.ui.colorfilter
 
-import android.content.Context
 import android.content.DialogInterface
 import androidx.activity.OnBackPressedCallback
 import com.google.android.material.dialog.MaterialAlertDialogBuilder
@@ -8,7 +7,7 @@ import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.core.util.ext.call
 
 class ColorFilterConfigBackPressedDispatcher(
-	private val context: Context,
+	private val activity: ColorFilterConfigActivity,
 	private val viewModel: ColorFilterConfigViewModel,
 ) : OnBackPressedCallback(true), DialogInterface.OnClickListener {
 
@@ -24,12 +23,12 @@ class ColorFilterConfigBackPressedDispatcher(
 		when (which) {
 			DialogInterface.BUTTON_NEGATIVE -> viewModel.onDismiss.call(Unit)
 			DialogInterface.BUTTON_NEUTRAL -> dialog.dismiss()
-			DialogInterface.BUTTON_POSITIVE -> viewModel.save()
+			DialogInterface.BUTTON_POSITIVE -> activity.showSaveConfirmation()
 		}
 	}
 
 	private fun showConfirmation() {
-		MaterialAlertDialogBuilder(context)
+		MaterialAlertDialogBuilder(activity)
 			.setTitle(R.string.color_correction)
 			.setMessage(R.string.text_unsaved_changes_prompt)
 			.setNegativeButton(R.string.discard, this)

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/colorfilter/ColorFilterConfigViewModel.kt

@@ -44,33 +44,19 @@ class ColorFilterConfigViewModel @Inject constructor(
 	}
 
 	fun setBrightness(brightness: Float) {
-		val cf = colorFilter.value
-		colorFilter.value = ReaderColorFilter(
-			brightness = brightness,
-			contrast = cf?.contrast ?: 0f,
-			isInverted = cf?.isInverted ?: false,
-		).takeUnless { it.isEmpty }
+		updateColorFilter { it.copy(brightness = brightness) }
 	}
 
 	fun setContrast(contrast: Float) {
-		val cf = colorFilter.value
-		colorFilter.value = ReaderColorFilter(
-			brightness = cf?.brightness ?: 0f,
-			contrast = contrast,
-			isInverted = cf?.isInverted ?: false,
-		).takeUnless { it.isEmpty }
+		updateColorFilter { it.copy(contrast = contrast) }
 	}
 
 	fun setInversion(invert: Boolean) {
-		val cf = colorFilter.value
-		if (invert == cf?.isInverted) {
-			return
-		}
-		colorFilter.value = ReaderColorFilter(
-			brightness = cf?.brightness ?: 0f,
-			contrast = cf?.contrast ?: 0f,
-			isInverted = invert,
-		).takeUnless { it.isEmpty }
+		updateColorFilter { it.copy(isInverted = invert) }
+	}
+
+	fun setGrayscale(grayscale: Boolean) {
+		updateColorFilter { it.copy(isGrayscale = grayscale) }
 	}
 
 	fun reset() {
@@ -85,7 +71,18 @@ class ColorFilterConfigViewModel @Inject constructor(
 	}
 
 	fun saveGlobally() {
-		settings.readerColorFilter = colorFilter.value
-		onDismiss.call(Unit)
+		launchLoadingJob(Dispatchers.Default) {
+			settings.readerColorFilter = colorFilter.value
+			if (mangaDataRepository.getColorFilter(manga.id) != null) {
+				mangaDataRepository.saveColorFilter(manga, colorFilter.value)
+			}
+			onDismiss.call(Unit)
+		}
+	}
+
+	private inline fun updateColorFilter(block: (ReaderColorFilter) -> ReaderColorFilter) {
+		colorFilter.value = block(
+			colorFilter.value ?: ReaderColorFilter.EMPTY,
+		).takeUnless { it.isEmpty }
 	}
 }

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/config/ReaderSettings.kt

@@ -102,10 +102,10 @@ class ReaderSettings(
 			AppSettings.KEY_READER_BACKGROUND,
 			AppSettings.KEY_32BIT_COLOR,
 			AppSettings.KEY_READER_OPTIMIZE,
-			AppSettings.KEY_CF_ENABLED,
 			AppSettings.KEY_CF_CONTRAST,
 			AppSettings.KEY_CF_BRIGHTNESS,
 			AppSettings.KEY_CF_INVERTED,
+			AppSettings.KEY_CF_GRAYSCALE,
 		)
 
 		override suspend fun emit(value: ReaderColorFilter?) {