libraries/screenshot/src/main/java/platform/test/screenshot/Bitmap.kt

/*
 * Copyright (C) 2022 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 platform.test.screenshot

import android.graphics.Bitmap
import android.graphics.Canvas
import android.os.Build
import android.view.View
import platform.test.screenshot.matchers.MSSIMMatcher
import platform.test.screenshot.matchers.PixelPerfectMatcher

/** Draw this [View] into a [Bitmap]. */
// TODO(b/195673633): Remove this once Compose screenshot tests use hardware rendering for their
// tests.
fun View.drawIntoBitmap(): Bitmap {
    val bitmap =
        Bitmap.createBitmap(
            measuredWidth,
            measuredHeight,
            Bitmap.Config.ARGB_8888,
        )
    val canvas = Canvas(bitmap)
    draw(canvas)
    return bitmap
}

/**
 * The [BitmapMatcher][platform.test.screenshot.matchers.BitmapMatcher] that should be used for
 * screenshot *unit* tests.
 */
val UnitTestBitmapMatcher =
    if (Build.CPU_ABI == "x86_64") {
        // Different CPU architectures can sometimes end up rendering differently, so we can't do
        // pixel-perfect matching on different architectures using the same golden. Given that our
        // presubmits are run on cf_x86_64_phone, our goldens should be perfectly matched on the
        // x86_64 architecture and use the Structural Similarity Index on others.
        // TODO(b/237511747): Run our screenshot presubmit tests on arm64 instead so that we can
        // do pixel perfect matching both at presubmit time and at development time with actual
        // devices.
        PixelPerfectMatcher()
    } else {
        MSSIMMatcher()
    }

/**
 * The [BitmapMatcher][platform.test.screenshot.matchers.BitmapMatcher] that should be used for
 * screenshot *unit* tests.
 *
 * We use the Structural Similarity Index for integration tests because they usually contain
 * additional information and noise that shouldn't break the test.
 */
val IntegrationTestBitmapMatcher = MSSIMMatcher()