Pages color filter implementation draft

app/src/main/java/org/koitharu/kotatsu/favourites/ui/categories/edit/FavouritesCategoryEditActivity.kt

@@ -14,6 +14,7 @@ import androidx.core.graphics.Insets
 import androidx.core.view.isVisible
 import androidx.core.view.updateLayoutParams
 import androidx.core.view.updatePadding
+import com.google.android.material.R as materialR
 import dagger.hilt.android.AndroidEntryPoint
 import javax.inject.Inject
 import org.koitharu.kotatsu.R
@@ -46,7 +47,7 @@ class FavouritesCategoryEditActivity :
 		setContentView(ActivityCategoryEditBinding.inflate(layoutInflater))
 		supportActionBar?.run {
 			setDisplayHomeAsUpEnabled(true)
-			setHomeAsUpIndicator(com.google.android.material.R.drawable.abc_ic_clear_material)
+			setHomeAsUpIndicator(materialR.drawable.abc_ic_clear_material)
 		}
 		initSortSpinner()
 		binding.buttonDone.setOnClickListener(this)

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

@@ -0,0 +1,108 @@
+package org.koitharu.kotatsu.reader.ui.colorfilter
+
+import android.content.Context
+import android.content.Intent
+import android.graphics.Color
+import android.graphics.LightingColorFilter
+import android.os.Bundle
+import android.view.ViewGroup
+import androidx.core.graphics.Insets
+import androidx.core.view.updateLayoutParams
+import androidx.core.view.updatePadding
+import androidx.lifecycle.lifecycleScope
+import coil.ImageLoader
+import coil.request.ImageRequest
+import coil.size.Scale
+import coil.size.ViewSizeResolver
+import com.google.android.material.slider.Slider
+import dagger.hilt.android.AndroidEntryPoint
+import kotlinx.coroutines.launch
+import org.koitharu.kotatsu.base.ui.BaseActivity
+import org.koitharu.kotatsu.core.model.parcelable.ParcelableMangaPages
+import org.koitharu.kotatsu.core.parser.MangaRepository
+import org.koitharu.kotatsu.databinding.ActivityColorFilterBinding
+import org.koitharu.kotatsu.parsers.model.MangaPage
+import org.koitharu.kotatsu.utils.ext.enqueueWith
+import org.koitharu.kotatsu.utils.ext.referer
+import javax.inject.Inject
+import kotlin.math.roundToInt
+import com.google.android.material.R as materialR
+
+@AndroidEntryPoint
+class ColorFilterConfigActivity : BaseActivity<ActivityColorFilterBinding>(), Slider.OnChangeListener {
+
+	@Inject
+	lateinit var coil: ImageLoader
+
+	@Inject
+	lateinit var mangaRepositoryFacotry: MangaRepository.Factory
+
+	override fun onCreate(savedInstanceState: Bundle?) {
+		super.onCreate(savedInstanceState)
+		setContentView(ActivityColorFilterBinding.inflate(layoutInflater))
+		supportActionBar?.run {
+			setDisplayHomeAsUpEnabled(true)
+			setHomeAsUpIndicator(materialR.drawable.abc_ic_clear_material)
+		}
+		binding.sliderLightness.addOnChangeListener(this)
+		binding.sliderSaturation.addOnChangeListener(this)
+		initPreview()
+		updateFilter()
+	}
+
+	override fun onValueChange(slider: Slider, value: Float, fromUser: Boolean) {
+		updateFilter()
+	}
+
+	override fun onWindowInsetsChanged(insets: Insets) {
+		binding.root.updatePadding(
+			left = insets.left,
+			right = insets.right,
+		)
+		binding.scrollView.updatePadding(
+			bottom = insets.bottom,
+		)
+		binding.toolbar.updateLayoutParams<ViewGroup.MarginLayoutParams> {
+			topMargin = insets.top
+		}
+	}
+
+	private fun updateFilter() {
+
+		fun Int.toColor() = Color.rgb(this, this, this)
+
+		val cf = LightingColorFilter(
+			binding.sliderSaturation.value.roundToInt().toColor(),
+			binding.sliderLightness.value.roundToInt().toColor(),
+		)
+		binding.imageViewAfter.colorFilter = cf
+	}
+
+	private fun initPreview() {
+		val page = intent?.getParcelableExtra<ParcelableMangaPages>(EXTRA_PAGES)?.pages?.firstOrNull()
+		if (page == null) {
+			finishAfterTransition()
+			return
+		}
+		lifecycleScope.launch {
+			val repository = mangaRepositoryFacotry.create(page.source)
+			val url = repository.getPageUrl(page)
+			ImageRequest.Builder(this@ColorFilterConfigActivity)
+				.data(url)
+				.referer(page.referer)
+				.scale(Scale.FILL)
+				.size(ViewSizeResolver(binding.imageViewBefore))
+				.allowRgb565(false)
+				.target(ShadowViewTarget(binding.imageViewBefore, binding.imageViewAfter))
+				.enqueueWith(coil)
+		}
+	}
+
+	companion object {
+
+		private const val EXTRA_PAGES = "pages"
+
+		fun newIntent(context: Context, page: MangaPage) = Intent(context, ColorFilterConfigActivity::class.java)
+			.putExtra(EXTRA_PAGES, ParcelableMangaPages(listOf(page)))
+	}
+}

app/src/main/java/org/koitharu/kotatsu/reader/ui/colorfilter/ShadowViewTarget.kt

@@ -0,0 +1,18 @@
+package org.koitharu.kotatsu.reader.ui.colorfilter
+
+import android.graphics.drawable.Drawable
+import android.widget.ImageView
+import coil.target.ImageViewTarget
+
+class ShadowViewTarget(
+	view: ImageView,
+	private val shadowView: ImageView,
+) : ImageViewTarget(view) {
+
+	override var drawable: Drawable?
+		get() = super.drawable
+		set(value) {
+			super.drawable = value
+			shadowView.setImageDrawable(value?.constantState?.newDrawable())
+		}
+}

app/src/main/java/org/koitharu/kotatsu/reader/ui/config/ReaderConfigBottomSheet.kt

@@ -20,6 +20,7 @@ import org.koitharu.kotatsu.core.prefs.ReaderMode
 import org.koitharu.kotatsu.databinding.SheetReaderConfigBinding
 import org.koitharu.kotatsu.reader.ui.PageSaveContract
 import org.koitharu.kotatsu.reader.ui.ReaderViewModel
+import org.koitharu.kotatsu.reader.ui.colorfilter.ColorFilterConfigActivity
 import org.koitharu.kotatsu.settings.SettingsActivity
 import org.koitharu.kotatsu.utils.ScreenOrientationHelper
 import org.koitharu.kotatsu.utils.ext.viewLifecycleScope
@@ -59,6 +60,7 @@ class ReaderConfigBottomSheet :
 		binding.buttonSavePage.setOnClickListener(this)
 		binding.buttonScreenRotate.setOnClickListener(this)
 		binding.buttonSettings.setOnClickListener(this)
+		binding.buttonColorFilter.setOnClickListener(this)
 		binding.sliderTimer.addOnSliderTouchListener(this)
 		binding.sliderTimer.setLabelFormatter(PageSwitchTimer.DelayLabelFormatter(view.resources))
 
@@ -80,6 +82,10 @@ class ReaderConfigBottomSheet :
 			R.id.button_screen_rotate -> {
 				orientationHelper?.toggleOrientation()
 			}
+			R.id.button_color_filter -> {
+				val page = viewModel.getCurrentPage() ?: return
+				startActivity(ColorFilterConfigActivity.newIntent(v.context, page))
+			}
 		}
 	}