[Sample] [Graphic] - Implementation of "Visualizing an UltraHDR Gainmap"

samples/README.md

@@ -80,6 +80,8 @@ Shows the recommended flow to request single runtime permissions
 The sample demonstrates the importance of having proper labels for
 - [TextSpan](user-interface/text/src/main/java/com/example/platform/ui/text/TextSpan.kt):
 buildSpannedString is useful for quickly building a rich text.
+- [Visualizing an UltraHDR Gainmap](graphics/ultrahdr/src/main/java/com/example/platform/graphics/ultrahdr/display/VisualizingAnUltraHDRGainmap.kt):
+This sample demonstrates visualizing the underlying gainmap of an UltraHDR 
 - [WindowInsetsAnimation](user-interface/window-insets/src/main/java/com/example/platform/ui/insets/WindowInsetsAnimation.kt):
 Shows how to react to the on-screen keyboard (IME) changing visibility, and also controlling the IME's visibility.
 - [WindowManager](user-interface/windowmanager/src/main/java/com/example/platform/ui/windowmanager/demos/WindowDemosActivity.kt):

samples/graphics/ultrahdr/src/main/java/com/example/platform/graphics/ultrahdr/display/VisualizingAnUltraHDRGainmap.kt

@@ -0,0 +1,157 @@
+/*
+ * Copyright 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.platform.graphics.ultrahdr.display
+
+import android.graphics.Bitmap
+import android.graphics.BitmapFactory
+import android.graphics.Canvas
+import android.graphics.ColorMatrixColorFilter
+import android.graphics.Gainmap
+import android.graphics.Paint
+import android.os.Build
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.RadioButton
+import androidx.annotation.RequiresApi
+import androidx.fragment.app.Fragment
+import com.example.platform.graphics.ultrahdr.databinding.VisualizingAnUltrahdrGainmapBinding
+import com.google.android.catalog.framework.annotations.Sample
+
+@Sample(
+    name = "Visualizing an UltraHDR Gainmap",
+    description = "This sample demonstrates visualizing the underlying gainmap of an UltraHDR " +
+            "image, which reveals which parts of the image are enhanced by the gainmap.",
+    documentation = "https://developer.android.com/guide/topics/media/hdr-image-format",
+    tags = ["ultrahdr"],
+)
+@RequiresApi(Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
+
+class VisualizingAnUltraHDRGainmap : Fragment() {
+    private enum class Type(val value: Int) {
+        JPEG(0),
+        GAINMAP(1),
+        COMBINED(2);
+
+        companion object {
+            fun fromInt(value: Int) = Type.values().first { it.value == value }
+        }
+    }
+
+    /**
+     *  Android ViewBinding.
+     */
+    private var _binding: VisualizingAnUltrahdrGainmapBinding? = null
+    private val binding get() = _binding!!
+
+    override fun onCreateView(
+        inflater: LayoutInflater,
+        container: ViewGroup?,
+        savedInstanceState: Bundle?,
+    ): View {
+        _binding = VisualizingAnUltrahdrGainmapBinding.inflate(inflater, container, false)
+        return binding.root
+    }
+
+    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+        super.onViewCreated(view, savedInstanceState)
+
+        // The ColorModeControls Class contain the necessary function to change the activities
+        // ColorMode to HDR, which allows and UltraHDRs images gain map to be used to enhance the
+        // image.
+        binding.colorModeControls.setWindow(requireActivity().window)
+        binding.modeSelectionGroup.setOnCheckedChangeListener { group, i ->
+            val selected = group.findViewById<RadioButton>(i)
+            val index = group.indexOfChild(selected)
+            updateDisplayedImage(Type.fromInt(index))
+        }
+
+        binding.modeJpeg.isChecked = true
+    }
+
+    /**
+     * Updated the currently displayed image. This allows users to visualize the SDR image alone,
+     * the gainmap as well as the result of the both of them displayed together.
+     */
+    private fun updateDisplayedImage(type: Type) {
+        // Clear previous bitmap source.
+        val imageview = binding.imageContainer
+        imageview.setImageResource(0)
+
+        // Decode ultra hdr image into bitmap data.
+        val stream = context?.assets?.open(ULTRA_HDR_IMAGE_FOUNTAIN)
+        val imageBitmap = BitmapFactory.decodeStream(stream)
+
+        // Based on the type, setting the appropriate bitmap.
+        imageview.setImageBitmap(
+            when (type) {
+                // Intentionally drop the gainmap in order to display 8-bit jpeg sdr image. This
+                // demonstrates that even if the activity is in HDR mode, SDR images will
+                // remain unchanged.
+                Type.JPEG -> imageBitmap.apply { gainmap = null }
+
+                // Create a visual version of the gainmap where you will be able to see exactly
+                // which parts of the UltraHDR image are being enhanced by the gainmap.
+                Type.GAINMAP -> visualizeGainmap(imageBitmap.gainmap!!)
+
+                // Do nothing.
+                Type.COMBINED -> imageBitmap
+            },
+        )
+    }
+
+    /**
+     * Creates a monochrome representation of the [Gainmap] of an UltraHDR image and returns it as
+     * a [Bitmap].
+     */
+    private fun visualizeGainmap(gainmap: Gainmap): Bitmap {
+        val contents = gainmap.gainmapContents
+        if (contents.config != Bitmap.Config.ALPHA_8) return contents
+
+        val visual = Bitmap.createBitmap(
+            contents.width, contents.height,
+            Bitmap.Config.ARGB_8888,
+        )
+
+        val canvas = Canvas(visual)
+        val paint = Paint()
+        paint.colorFilter = ColorMatrixColorFilter(
+            floatArrayOf(
+                0f, 0f, 0f, 1f, 0f,
+                0f, 0f, 0f, 1f, 0f,
+                0f, 0f, 0f, 1f, 0f,
+                0f, 0f, 0f, 0f, 255f,
+            ),
+        )
+        canvas.drawBitmap(contents, 0f, 0f, paint)
+        canvas.setBitmap(null)
+        return visual
+    }
+
+    override fun onDetach() {
+        super.onDetach()
+        binding.colorModeControls.detach()
+    }
+
+    companion object {
+        /**
+         * Sample UltraHDR image path
+         */
+        private const val ULTRA_HDR_IMAGE_FOUNTAIN = "gainmaps/fountain_night.jpg"
+    }
+}

samples/graphics/ultrahdr/src/main/res/layout/visualizing_an_ultrahdr_gainmap.xml

@@ -0,0 +1,64 @@
+<?xml version="1.0" encoding="utf-8"?><!--
+  ~ Copyright (C) 2023 The Android Open Source Project
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~      http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical">
+
+    <com.example.platform.graphics.ultrahdr.common.ColorModeControls
+        android:id="@+id/color_mode_controls"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content" />
+
+    <RadioGroup
+        android:id="@+id/mode_selection_group"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="@dimen/ultrahdr_color_mode_current_mode_padding"
+        android:layout_marginTop="@dimen/ultrahdr_color_mode_current_mode_padding"
+        android:layout_marginEnd="@dimen/ultrahdr_color_mode_current_mode_padding"
+        android:orientation="horizontal">
+
+        <RadioButton
+            android:id="@+id/mode_jpeg"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:text="@string/visualizing_ultrahdr_gainmap_mode_title_jpeg" />
+
+        <RadioButton
+            android:id="@+id/mode_gainmap"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:text="@string/visualizing_ultrahdr_gainmap_mode_title_gainmap" />
+
+        <RadioButton
+            android:id="@+id/mode_both"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:text="@string/visualizing_ultrahdr_gainmap_mode_title_both" />
+    </RadioGroup>
+
+    <ImageView
+        android:id="@+id/image_container"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:layout_gravity="center_horizontal"
+        android:contentDescription="@null" />
+
+</LinearLayout>

samples/graphics/ultrahdr/src/main/res/values/strings.xml

@@ -20,6 +20,11 @@
     <string name="displaying_ultrahdr_option_title_canyon">Grand Canyon</string>
     <string name="displaying_ultrahdr_option_title_train_station">Train Station</string>
 
+    <!-- Visualizing An UltraHDR Gainmap String -->
+    <string name="visualizing_ultrahdr_gainmap_mode_title_jpeg">JPEG</string>
+    <string name="visualizing_ultrahdr_gainmap_mode_title_gainmap">Gainmap</string>
+    <string name="visualizing_ultrahdr_gainmap_mode_title_both">Both</string>
+
     <!-- ColorModeControls String -->
     <string name="color_mode_sdr">SDR</string>
     <string name="color_mode_hdr">HDR</string>