Utilized getPixels for applyBitmapFilter. I think the Bitmap class has a better way of adding filters to a bitmap, so more research needs to be done, but there is a slight performance increase nonetheless.

Author: therealbluepandabear

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

@@ -1,9 +1,7 @@
 package com.therealbluepandabear.pixapencil.activities.canvas.canvascommands
 
-import android.graphics.Color
 import com.therealbluepandabear.pixapencil.activities.canvas.CanvasActivity
-import com.therealbluepandabear.pixapencil.extensions.getPixel
-import com.therealbluepandabear.pixapencil.extensions.iterate
+import com.therealbluepandabear.pixapencil.extensions.filterBitmap
 import com.therealbluepandabear.pixapencil.fragments.canvas.pixelGridViewInstance
 import com.therealbluepandabear.pixapencil.models.BitmapAction
 
@@ -12,17 +10,10 @@ fun CanvasActivity.CanvasCommandsHelper.applyBitmapFilter(filterLambda: (Int) ->
     baseReference.viewModel.saved = false
     baseReference.viewModel.currentBitmapAction = BitmapAction(mutableListOf())
 
-    pixelGridViewInstance.pixelGridViewBitmap.iterate {
-        val colorAtCoordinates = pixelGridViewInstance.pixelGridViewBitmap.getPixel(it)
-
-        if (colorAtCoordinates != Color.TRANSPARENT) {
-            val color = filterLambda(colorAtCoordinates)
-
-            overrideSetPixel(it, color, ignoreBrush = true, ignoreSymmetry = true)
-        }
+    pixelGridViewInstance.pixelGridViewBitmap.filterBitmap(filterLambda) { coordinates, color ->
+        overrideSetPixel(coordinates, color, ignoreBrush = true, ignoreSymmetry = true)
     }
 
-
     baseReference.viewModel.bitmapActionData.add(baseReference.viewModel.currentBitmapAction!!)
     baseReference.viewModel.currentBitmapAction = null
 

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

@@ -8,14 +8,6 @@ import com.therealbluepandabear.pixapencil.enums.OverlayType
 import com.therealbluepandabear.pixapencil.models.Coordinates
 import com.therealbluepandabear.pixapencil.models.MatrixInfo
 
-fun Bitmap.iterate(func: (Coordinates) -> Unit) {
-    for (i_1 in 0 until width) {
-        for (i_2 in 0 until height) {
-            func.invoke(Coordinates(i_1, i_2))
-        }
-    }
-}
-
 fun Bitmap.size(): Int {
     return width * height
 }
@@ -59,6 +51,21 @@ fun Bitmap.getNumberOfUniqueColors(excludeTransparentPixels: Boolean = true): In
     return colors.size
 }
 
+fun Bitmap.filterBitmap(func: (Int) -> Int, func2: (Coordinates, Int) -> Unit) {
+    val array = IntArray(size())
+
+    getPixels(array, 0, width, 0, 0, width, height)
+
+    for (i in array.indices) {
+        val color = array[i]
+
+        if (color != Color.TRANSPARENT) {
+            val filteredColor = func(color)
+            func2.invoke(Coordinates.fromIndex(i, width), filteredColor)
+        }
+    }
+}
+
 fun Bitmap.getColors(): MutableList<Int> {
     val colors = mutableListOf<Int>()
     val array = IntArray(size())