Use getPixels and setPixels for Bitmap.replacePixelsByColor => massive performance increase (fix #166).

Author: therealbluepandabear

app/src/main/java/com/therealbluepandabear/pixapencil/activities/canvas/canvascommands/CanvasActivity+CanvasCommandsHelper+replacePixelsByColor.kt

@@ -1,8 +1,7 @@
 package com.therealbluepandabear.pixapencil.activities.canvas.canvascommands
 
 import com.therealbluepandabear.pixapencil.activities.canvas.CanvasActivity
-import com.therealbluepandabear.pixapencil.extensions.getPixel
-import com.therealbluepandabear.pixapencil.extensions.iterate
+import com.therealbluepandabear.pixapencil.extensions.replacePixelsByColor
 import com.therealbluepandabear.pixapencil.fragments.canvas.pixelGridViewInstance
 import com.therealbluepandabear.pixapencil.models.BitmapAction
 
@@ -11,10 +10,8 @@ fun CanvasActivity.CanvasCommandsHelper.replacePixelsByColor(colorToFind: Int, c
 
     baseReference.viewModel.currentBitmapAction = BitmapAction(mutableListOf())
 
-    pixelGridViewInstance.pixelGridViewBitmap.iterate {
-        if (pixelGridViewInstance.pixelGridViewBitmap.getPixel(it) == colorToFind) {
-            overrideSetPixel(it, colorToReplace, true, ignoreSymmetry = true, ignoreDither = true, ignoreShadingMap = true)
-        }
+    pixelGridViewInstance.pixelGridViewBitmap.replacePixelsByColor(colorToFind, colorToReplace) {
+        overrideSetPixel(it, colorToReplace, true, ignoreSymmetry = true, ignoreDither = true, ignoreShadingMap = true)
     }
 
     baseReference.viewModel.bitmapActionData.add(baseReference.viewModel.currentBitmapAction!!)

app/src/main/java/com/therealbluepandabear/pixapencil/extensions/BitmapExtensions.kt

@@ -4,10 +4,12 @@ import android.graphics.Bitmap
 import android.graphics.Canvas
 import android.graphics.Color
 import android.graphics.Matrix
+import android.util.Log
 import com.therealbluepandabear.pixapencil.enums.OverlayType
-import com.therealbluepandabear.pixapencil.fragments.canvas.pixelGridViewInstance
 import com.therealbluepandabear.pixapencil.models.Coordinates
 import com.therealbluepandabear.pixapencil.models.MatrixInfo
+import kotlin.math.ceil
+import kotlin.system.measureTimeMillis
 
 fun Bitmap.iterate(func: (Coordinates) -> Unit) {
     for (i_1 in 0 until width) {
@@ -17,12 +19,30 @@ fun Bitmap.iterate(func: (Coordinates) -> Unit) {
     }
 }
 
-fun Bitmap.replacePixelsByColor(colorToFind: Int, colorToReplace: Int) {
-    iterate {
-        if (getPixel(it) == colorToFind) {
-            setPixel(it, colorToReplace)
+fun Bitmap.size(): Int {
+    return width * height
+}
+
+/** Thank you to to confucius on StackOverflow for this solution.
+ *
+ * - [Link to confucius' profile](https://stackoverflow.com/users/671676/confucius)
+ * - [Original StackOverFlow post](https://stackoverflow.com/questions/7237915/replace-black-color-in-bitmap-with-red)
+ * **/
+
+fun Bitmap.replacePixelsByColor(colorToFind: Int, colorToReplace: Int, func: ((Coordinates) -> Unit)? = null) {
+    val array = IntArray(size())
+
+    getPixels(array, 0, width, 0, 0, width, height)
+
+    for (i in array.indices) {
+        if (array[i] == colorToFind) {
+            array[i] = colorToReplace
+
+            func?.invoke(Coordinates.fromIndex(i, width))
         }
     }
+
+    setPixels(array, 0, width, 0, 0, width, height)
 }
 
 fun Bitmap.getNumberOfUniqueColors(excludeTransparentPixels: Boolean = true): Int {

app/src/main/java/com/therealbluepandabear/pixapencil/fragments/findandreplace/FindAndReplaceFragment.kt

@@ -5,8 +5,6 @@ import android.graphics.Bitmap
 import android.os.Bundle
 import android.view.*
 import androidx.core.view.MenuHost
-import androidx.core.view.MenuProvider
-import androidx.core.view.children
 import androidx.fragment.app.Fragment
 import androidx.lifecycle.Lifecycle
 import androidx.recyclerview.widget.LinearLayoutManager

app/src/main/java/com/therealbluepandabear/pixapencil/models/Coordinates.kt

@@ -1,5 +1,7 @@
 package com.therealbluepandabear.pixapencil.models
 
+import kotlin.math.floor
+
 data class Coordinates(val x: Int, val y: Int) {
     private fun swap(): Coordinates {
         return Coordinates(y, x)
@@ -65,5 +67,13 @@ data class Coordinates(val x: Int, val y: Int) {
         fun staticSet(x: Int, y: Int): Coordinates {
             return Coordinates(x, y)
         }
+
+        // thanks to PapaBread for this solution ;)
+        fun fromIndex(index: Int, bitmapWidth: Int): Coordinates {
+            return Coordinates(
+                x = (index.toDouble() % bitmapWidth.toDouble()).toInt(),
+                y = floor(index.toDouble() / bitmapWidth).toInt()
+            )
+        }
     }
 }