Add TintPostProcessor to Fresco PostProcessors

Reviewed By: oprisnik

Differential Revision: D54691638

fbshipit-source-id: f1068d7fd5e3a0c7dea78557d36851d3739c24c8

imagepipeline/src/main/java/com/facebook/imagepipeline/postprocessors/TintPostProcessor.kt

@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+package com.facebook.imagepipeline.postprocessors
+
+import android.graphics.Bitmap
+import android.graphics.Canvas
+import android.graphics.PorterDuff
+import androidx.annotation.ColorInt
+import androidx.core.graphics.ColorUtils
+import com.facebook.cache.common.CacheKey
+import com.facebook.cache.common.SimpleCacheKey
+import com.facebook.imagepipeline.request.BasePostprocessor
+
+/**
+ * Postprocessor that adds a semi-transparent tint to a bitmap.
+ *
+ * By default it will add a tint over every pixel in the bitmap. A PorterDuff.Mode may be provided
+ * for custom draw behavior. PorterDuff.Mode.SRC_ATOP will avoid drawing over transparent pixels.
+ *
+ * For example: Providing color: Color.WHITE and alpha: 0.5f will brighten the image.
+ *
+ * @param color The color to tint the image with. Ex: Color.WHITE, Color.BLACK
+ * @param alphaPercent Sets the alpha bits of the color param for tinting, if provided. 0.0 - 1.0
+ * @param porterDuffMode The PorterDuff.Mode to use for drawing, or null to draw over every pixel.
+ */
+class TintPostProcessor(
+    @ColorInt color: Int,
+    alphaPercent: Float? = null,
+    private val porterDuffMode: PorterDuff.Mode? = null
+) : BasePostprocessor() {
+  @ColorInt
+  private val tintColor: Int =
+      if (alphaPercent != null) {
+        ColorUtils.setAlphaComponent(color, (alphaPercent * 255).toInt().coerceIn(0, 255))
+      } else {
+        color
+      }
+
+  private val cacheKey: CacheKey =
+      SimpleCacheKey("Tint. tintColor=$tintColor, mode=$porterDuffMode")
+
+  override fun process(
+      sourceBitmap: Bitmap,
+  ) {
+    if (porterDuffMode == null) {
+      Canvas(sourceBitmap).drawColor(tintColor)
+    } else {
+      Canvas(sourceBitmap).drawColor(tintColor, porterDuffMode)
+    }
+  }
+
+  override fun getName(): String = TintPostProcessor::class.toString()
+
+  override fun getPostprocessorCacheKey(): CacheKey = cacheKey
+}