add tolerance to bitmap snapshotting

Author: balazstothofficial

snapshot/src/androidMain/kotlin/com/quickbird/snapshot/Bitmap+updatePixels.kt

@@ -2,11 +2,11 @@ package com.quickbird.snapshot
 
 import android.graphics.Bitmap
 
-internal fun Bitmap.updatePixels(update: (x: Int, y: Int, color: Int) -> Int) {
+internal fun Bitmap.updatePixels(update: (x: Int, y: Int, color: Color) -> Color) {
     (0 until width).map { x ->
         (0 until height).map { y ->
-            val updated = update(x, y, getPixel(x, y))
-            setPixel(x, y, updated)
+            val updated = update(x, y, getPixel(x, y).color)
+            setPixel(x, y, updated.value)
         }
     }
 }

snapshot/src/androidMain/kotlin/com/quickbird/snapshot/Color.kt

@@ -0,0 +1,8 @@
+package com.quickbird.snapshot
+
+import androidx.annotation.ColorInt
+
+data class Color(@ColorInt val value: Int)
+
+val @receiver:ColorInt Int.color
+    get() = Color(this)

snapshot/src/androidMain/kotlin/com/quickbird/snapshot/Diffing+bitmap.kt

@@ -1,28 +1,49 @@
 package com.quickbird.snapshot
 
 import android.graphics.Bitmap
-import android.graphics.Color
+import android.graphics.Color as AndroidColor
 
-// TODO: Wrap Color
-fun Diffing.Companion.bitmap(colorDiffing: Diffing<Int>) = Diffing<Bitmap> { first, second ->
-    if (first.asByteArray().contentEquals(second.asByteArray())) null
+fun Diffing.Companion.bitmap(
+    colorDiffing: Diffing<Color>,
+    tolerance: Double = 0.0
+) = Diffing<Bitmap> { first, second ->
+    val difference = first differenceTo second
+
+    if (difference <= tolerance) null
     else first.copy(first.config, true).apply {
         updatePixels { x, y, color ->
             if (x < second.width && y < second.height)
-                colorDiffing(color, second.getPixel(x, y)) ?: color
+                colorDiffing(color, second.getPixel(x, y).color) ?: color
             else color
         }
     }
 }
 
 val Diffing.Companion.colorRed
-    get() = Diffing<Int> { first, second ->
-        if (first == second) null
-        else Color.RED
-    }
+    get() = color(AndroidColor.RED.color)
+
+fun Diffing.Companion.color(differenceColor: Color) = Diffing<Color> { first, second ->
+    if (first == second) null
+    else differenceColor
+}
+
+val Diffing.Companion.colorMean
+    get() = intMean.wrap(::Color, Color::value)
 
 val Diffing.Companion.intMean
     get() = Diffing<Int> { first, second ->
         if (first == second) null
         else first / 2 + second / 2
     }
+
+private infix fun Bitmap.differenceTo(other: Bitmap): Double {
+    val thisBytes = this.asByteArray()
+    val otherBytes = other.asByteArray()
+    if (thisBytes == null || otherBytes == null || thisBytes.size != otherBytes.size) return 100.0
+
+    val differentBytes = thisBytes
+        .zip(otherBytes, Byte::equals)
+        .count { !it }
+
+    return differentBytes.toDouble() / thisBytes.size
+}

snapshot/src/androidMain/kotlin/com/quickbird/snapshot/Snapshotting+composeScreenshot.kt

@@ -9,7 +9,7 @@ import androidx.compose.ui.test.onRoot
 
 val Snapshotting.Companion.composeNodeScreenshot
     get() = Snapshotting(
-        diffing = Diffing.bitmap(colorDiffing = Diffing.intMean),
+        diffing = Diffing.bitmap(colorDiffing = Diffing.colorMean),
         snapshot = { node: SemanticsNodeInteraction -> node.captureToImage().asAndroidBitmap() }
     )
 

snapshot/src/androidMain/kotlin/com/quickbird/snapshot/Snapshotting+viewScreenshot.kt

@@ -6,7 +6,7 @@ import android.view.View
 
 val Snapshotting.Companion.viewScreenshot
     get() = Snapshotting(
-        diffing = Diffing.bitmap(colorDiffing = Diffing.intMean),
+        diffing = Diffing.bitmap(colorDiffing = Diffing.colorMean),
         snapshot = { view: View ->
             Bitmap.createBitmap(view.width, view.height, Bitmap.Config.ARGB_8888).apply {
                 view.draw(Canvas(this))

snapshot/src/jvmMain/kotlin/com/quickbird/snapshot/androidTransfer/AndroidSnapshotTestFiles.kt

@@ -11,7 +11,7 @@ data class AndroidSnapshotTestFiles(
     private val directory: AndroidSnapshotDirectory,
     private val appBundle: String,
     private val diffFilePrefix: String = "diff",
-    private val androidDirectory: String = "/data/data/$appBundle/files/snapshots",
+    private val androidDirectory: String = "/data/data/$appBundle/files/snapshot",
     private val tmpAndroidDirectory: String = "/sdcard/snapshot_tmp",
     private val deviceIds: List<String> = listAdbDevices()
 ) {