Transform & preserve gainmaps

Have Bitmap.createBitmap(sourceBitmap, ...) preserve any gainmaps if
present, transforming the gainmaps in the same way.

This addresses 2 common usages:

1) Rotating bitmaps to handle EXIF orientations
2) Bitmap.createScaledBitmap() to do "static" scaling

Bug: 286131154
Test: SilkFX GainmapTransformsTest
Change-Id: I5a62dccbb2c70bc38cca581b161eef792c8b2a78

graphics/java/android/graphics/Bitmap.java

@@ -997,12 +997,63 @@ public final class Bitmap implements Parcelable {
         canvas.concat(m);
         canvas.drawBitmap(source, srcR, dstR, paint);
         canvas.setBitmap(null);
+
+        // If the source has a gainmap, apply the same set of transformations to the gainmap
+        // and set it on the output
+        if (source.hasGainmap()) {
+            Bitmap newMapContents = transformGainmap(source, m, neww, newh, paint, srcR, dstR,
+                    deviceR);
+            if (newMapContents != null) {
+                bitmap.setGainmap(new Gainmap(source.getGainmap(), newMapContents));
+            }
+        }
+
         if (isHardware) {
             return bitmap.copy(Config.HARDWARE, false);
         }
         return bitmap;
     }
 
+    private static Bitmap transformGainmap(Bitmap source, Matrix m, int neww, int newh, Paint paint,
+            Rect srcR, RectF dstR, RectF deviceR) {
+        Canvas canvas;
+        Bitmap sourceGainmap = source.getGainmap().getGainmapContents();
+        // Gainmaps can be scaled relative to the base image (eg, 1/4th res)
+        // Preserve that relative scaling between the base & gainmap in the output
+        float scaleX = (sourceGainmap.getWidth() / (float) source.getWidth());
+        float scaleY = (sourceGainmap.getHeight() / (float) source.getHeight());
+        int mapw = Math.round(neww * scaleX);
+        int maph = Math.round(newh * scaleY);
+
+        if (mapw == 0 || maph == 0) {
+            // The gainmap has been scaled away entirely, drop it
+            return null;
+        }
+
+        // Scale the computed `srcR` used for rendering the source bitmap to the destination
+        // to be in gainmap dimensions
+        Rect gSrcR = new Rect((int) (srcR.left * scaleX),
+                (int) (srcR.top * scaleY), (int) (srcR.right * scaleX),
+                (int) (srcR.bottom * scaleY));
+
+        // Note: createBitmap isn't used as that requires a non-null colorspace, however
+        // gainmaps don't have a colorspace. So use `nativeCreate` directly to bypass
+        // that colorspace enforcement requirement (#getColorSpace() allows a null return)
+        Bitmap newMapContents = nativeCreate(null, 0, mapw, mapw, maph,
+                sourceGainmap.getConfig().nativeInt, true, 0);
+        newMapContents.eraseColor(0);
+        canvas = new Canvas(newMapContents);
+        // Scale the translate & matrix to be in gainmap-relative dimensions
+        canvas.scale(scaleX, scaleY);
+        canvas.translate(-deviceR.left, -deviceR.top);
+        canvas.concat(m);
+        canvas.drawBitmap(sourceGainmap, gSrcR, dstR, paint);
+        canvas.setBitmap(null);
+        // Create a new gainmap using a copy of the metadata information from the source but
+        // with the transformed bitmap created above
+        return newMapContents;
+    }
+
     /**
      * Returns a mutable bitmap with the specified width and height.  Its
      * initial density is as per {@link #getDensity}. The newly created

graphics/java/android/graphics/Gainmap.java

@@ -121,6 +121,16 @@ public final class Gainmap implements Parcelable {
         this(gainmapContents, nCreateEmpty());
     }
 
+    /**
+     * Creates a new gainmap using the provided gainmap as the metadata source and the provided
+     * bitmap as the replacement for the gainmapContents
+     * TODO: Make public, it's useful
+     * @hide
+     */
+    public Gainmap(@NonNull Gainmap gainmap, @NonNull Bitmap gainmapContents) {
+        this(gainmapContents, nCreateCopy(gainmap.mNativePtr));
+    }
+
     /**
      * @return Returns the image data of the gainmap represented as a Bitmap. This is represented
      * as a Bitmap for broad API compatibility, however certain aspects of the Bitmap are ignored
@@ -325,6 +335,7 @@ public final class Gainmap implements Parcelable {
 
     private static native long nGetFinalizer();
     private static native long nCreateEmpty();
+    private static native long nCreateCopy(long source);
 
     private static native void nSetBitmap(long ptr, Bitmap bitmap);
 

libs/hwui/jni/Gainmap.cpp

@@ -86,6 +86,16 @@ jlong Gainmap_createEmpty(JNIEnv*, jobject) {
     return static_cast<jlong>(reinterpret_cast<uintptr_t>(gainmap));
 }
 
+jlong Gainmap_createCopy(JNIEnv*, jobject, jlong sourcePtr) {
+    Gainmap* gainmap = new Gainmap();
+    gainmap->incStrong(0);
+    if (sourcePtr) {
+        Gainmap* src = fromJava(sourcePtr);
+        gainmap->info = src->info;
+    }
+    return static_cast<jlong>(reinterpret_cast<uintptr_t>(gainmap));
+}
+
 static void Gainmap_setBitmap(JNIEnv* env, jobject, jlong gainmapPtr, jobject jBitmap) {
     android::Bitmap* bitmap = GraphicsJNI::getNativeBitmap(env, jBitmap);
     fromJava(gainmapPtr)->bitmap = sk_ref_sp(bitmap);
@@ -237,6 +247,7 @@ static void Gainmap_readFromParcel(JNIEnv* env, jobject, jlong nativeObject, job
 static const JNINativeMethod gGainmapMethods[] = {
         {"nGetFinalizer", "()J", (void*)Gainmap_getNativeFinalizer},
         {"nCreateEmpty", "()J", (void*)Gainmap_createEmpty},
+        {"nCreateCopy", "(J)J", (void*)Gainmap_createCopy},
         {"nSetBitmap", "(JLandroid/graphics/Bitmap;)V", (void*)Gainmap_setBitmap},
         {"nSetRatioMin", "(JFFF)V", (void*)Gainmap_setRatioMin},
         {"nGetRatioMin", "(J[F)V", (void*)Gainmap_getRatioMin},

tests/SilkFX/res/layout/gainmap_transform_test.xml

@@ -0,0 +1,122 @@
+<?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.
+  -->
+
+<com.android.test.silkfx.hdr.GainmapTransformsTest xmlns:android="http://schemas.android.com/apk/res/android"
+                                               android:layout_width="match_parent"
+                                               android:layout_height="match_parent"
+                                               android:orientation="vertical">
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="horizontal">
+
+        <Button
+            android:id="@+id/original"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:text="Original" />
+
+        <Button
+            android:id="@+id/scaled"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:text="Scaled (1/3)" />
+
+        <Button
+            android:id="@+id/rotate_90"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:text="Rotate 90" />
+
+        <Button
+            android:id="@+id/rotate_90_scaled"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:text="Rot90+Scale" />
+
+        <Button
+            android:id="@+id/crop"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:text="Crop" />
+
+        <Button
+            android:id="@+id/crop_200"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:text="Crop 200" />
+
+    </LinearLayout>
+
+    <TextView
+        android:id="@+id/source_info"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content" />
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:orientation="horizontal">
+
+        <LinearLayout
+            android:layout_width="0dp"
+            android:layout_height="match_parent"
+            android:orientation="vertical"
+            android:layout_weight="1">
+
+            <TextView
+                android:id="@+id/sdr_label"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content" />
+
+            <ImageView
+                android:id="@+id/sdr_source"
+                android:layout_width="match_parent"
+                android:layout_height="match_parent"
+                android:layout_margin="8dp"
+                android:scaleType="fitStart" />
+        </LinearLayout>
+
+        <LinearLayout
+            android:layout_width="0dp"
+            android:layout_height="match_parent"
+            android:orientation="vertical"
+            android:layout_weight="1">
+
+            <TextView
+                android:id="@+id/gainmap_label"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content" />
+
+            <ImageView
+                android:id="@+id/gainmap"
+                android:layout_width="match_parent"
+                android:layout_height="match_parent"
+                android:layout_margin="8dp"
+                android:scaleType="fitStart" />
+        </LinearLayout>
+
+    </LinearLayout>
+
+</com.android.test.silkfx.hdr.GainmapTransformsTest>

tests/SilkFX/src/com/android/test/silkfx/Main.kt

@@ -55,7 +55,9 @@ private val AllDemos = listOf(
                 Demo("Color Grid", R.layout.color_grid),
                 Demo("Gradient Sweep", R.layout.gradient_sweep),
                 Demo("Gainmap Image", R.layout.gainmap_image),
-                Demo("Gainmap Decode Test", R.layout.gainmap_decode_test, commonControls = false)
+                Demo("Gainmap Decode Test", R.layout.gainmap_decode_test, commonControls = false),
+                Demo("Gainmap Transform Test", R.layout.gainmap_transform_test,
+                        commonControls = false)
         )),
         DemoGroup("Materials", listOf(
                 Demo("Glass", GlassActivity::class),

tests/SilkFX/src/com/android/test/silkfx/hdr/GainmapDecodeTest.kt

@@ -17,7 +17,12 @@
 package com.android.test.silkfx.hdr
 
 import android.content.Context
+import android.graphics.Bitmap
+import android.graphics.Canvas
+import android.graphics.ColorMatrixColorFilter
+import android.graphics.Gainmap
 import android.graphics.ImageDecoder
+import android.graphics.Paint
 import android.graphics.Rect
 import android.util.AttributeSet
 import android.widget.Button
@@ -34,6 +39,25 @@ enum class DecodeMode {
     CropedSquaredScaled33
 }
 
+fun gainmapVisualizer(gainmap: Gainmap): Bitmap {
+    val map = gainmap.gainmapContents
+    val gainmapVisualizer = Bitmap.createBitmap(map.width, map.height,
+            Bitmap.Config.ARGB_8888)
+    val canvas = Canvas(gainmapVisualizer!!)
+    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(map, 0f, 0f, paint)
+    canvas.setBitmap(null)
+    return gainmapVisualizer
+}
+
 class GainmapDecodeTest(context: Context, attrs: AttributeSet?) : LinearLayout(context, attrs) {
 
     private fun decode(mode: DecodeMode) {
@@ -71,7 +95,7 @@ class GainmapDecodeTest(context: Context, attrs: AttributeSet?) : LinearLayout(c
             }
         }
 
-        val gainmapContents = gainmapImage.gainmap!!.gainmapContents!!
+        val gainmapContents = gainmapImage.gainmap?.let { gainmapVisualizer(it) }
         val sdrBitmap = gainmapImage.also { it.gainmap = null }
 
         findViewById<ImageView>(R.id.sdr_source)!!.setImageBitmap(sdrBitmap)
@@ -80,7 +104,7 @@ class GainmapDecodeTest(context: Context, attrs: AttributeSet?) : LinearLayout(c
 
         findViewById<ImageView>(R.id.gainmap)!!.setImageBitmap(gainmapContents)
         findViewById<TextView>(R.id.gainmap_label)!!.text =
-            "Gainmap Size: ${gainmapContents.width}x${gainmapContents.height}"
+            "Gainmap Size: ${gainmapContents?.width ?: 0}x${gainmapContents?.height ?: 0}"
     }
 
     override fun onFinishInflate() {

tests/SilkFX/src/com/android/test/silkfx/hdr/GainmapTransformsTest.kt

@@ -0,0 +1,116 @@
+/*
+ * 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.
+ */
+
+package com.android.test.silkfx.hdr
+
+import android.content.Context
+import android.graphics.Bitmap
+import android.graphics.ImageDecoder
+import android.graphics.Matrix
+import android.util.AttributeSet
+import android.widget.Button
+import android.widget.ImageView
+import android.widget.LinearLayout
+import android.widget.TextView
+import com.android.test.silkfx.R
+
+class GainmapTransformsTest(context: Context, attrs: AttributeSet?) : LinearLayout(context, attrs) {
+
+    private val sourceImage = loadSample()
+
+    private fun loadSample(): Bitmap {
+        val source = ImageDecoder.createSource(resources.assets,
+                "gainmaps/${context.assets.list("gainmaps")!![0]}")
+
+        return ImageDecoder.decodeBitmap(source) { decoder, info, source ->
+            decoder.allocator = ImageDecoder.ALLOCATOR_SOFTWARE
+        }
+    }
+
+    private fun process(transform: (Bitmap) -> Bitmap) {
+        val result = transform(sourceImage)
+
+        val gainmapContents = result.gainmap?.let { gainmapVisualizer(it) }
+        val sdrBitmap = result.also { it.gainmap = null }
+
+        findViewById<ImageView>(R.id.sdr_source)!!.setImageBitmap(sdrBitmap)
+        findViewById<TextView>(R.id.sdr_label)!!.text =
+                "SDR Size: ${sdrBitmap.width}x${sdrBitmap.height}"
+
+        findViewById<ImageView>(R.id.gainmap)!!.setImageBitmap(gainmapContents)
+        findViewById<TextView>(R.id.gainmap_label)!!.text =
+                "Gainmap Size: ${gainmapContents?.width ?: 0}x${gainmapContents?.height ?: 0}"
+    }
+
+    override fun onFinishInflate() {
+        super.onFinishInflate()
+        val sourceInfo = findViewById<TextView>(R.id.source_info)!!
+        sourceInfo.text = "Original size ${sourceImage.width}x${sourceImage.height}"
+        process { it.copy(Bitmap.Config.ARGB_8888, false) }
+
+        findViewById<Button>(R.id.original)!!.setOnClickListener {
+            process { it.copy(Bitmap.Config.ARGB_8888, false) }
+        }
+
+        findViewById<Button>(R.id.scaled)!!.setOnClickListener {
+            process { Bitmap.createScaledBitmap(it, it.width / 3, it.height / 3, true) }
+        }
+
+        findViewById<Button>(R.id.rotate_90)!!.setOnClickListener {
+            process {
+                val width: Int = it.width
+                val height: Int = it.height
+
+                val m = Matrix()
+                m.setRotate(90.0f, (width / 2).toFloat(), (height / 2).toFloat())
+                Bitmap.createBitmap(it, 0, 0, width, height, m, false)
+            }
+        }
+
+        findViewById<Button>(R.id.rotate_90_scaled)!!.setOnClickListener {
+            process {
+                val width: Int = it.width
+                val height: Int = it.height
+
+                val m = Matrix()
+                m.setRotate(90.0f, (width / 2).toFloat(), (height / 2).toFloat())
+                m.preScale(.3f, .3f)
+                Bitmap.createBitmap(it, 0, 0, width, height, m, false)
+            }
+        }
+
+        findViewById<Button>(R.id.crop)!!.setOnClickListener {
+            process {
+                val width: Int = it.width
+                val height: Int = it.height
+                Bitmap.createBitmap(it, width / 2, height / 2,
+                        width / 4, height / 4, null, false)
+            }
+        }
+
+        findViewById<Button>(R.id.crop_200)!!.setOnClickListener {
+            process {
+                val width: Int = it.width
+                val height: Int = it.height
+
+                val m = Matrix()
+                m.setRotate(200.0f, (width / 2).toFloat(), (height / 2).toFloat())
+                Bitmap.createBitmap(it, width / 2, height / 2,
+                        width / 4, height / 4, m, false)
+            }
+        }
+    }
+}