From 1fd2e0eb1bd7a1503f39b3a3b659bf85734ac3db Mon Sep 17 00:00:00 2001
From: Xunkai Zhang <xunkai@google.com>
Date: Tue, 28 Apr 2020 08:16:54 -0700
Subject: [PATCH] [tfls.image] Add TensorImage.fromBitmap shortcut.

PiperOrigin-RevId: 308825884
Change-Id: Ic8939641a45507005f4fa05bbc03d0ba96c8c01c
---
 .../lite/support/image/TensorImage.java       | 26 ++++++++++++++-----
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/tensorflow/lite/experimental/support/java/src/java/org/tensorflow/lite/support/image/TensorImage.java b/tensorflow/lite/experimental/support/java/src/java/org/tensorflow/lite/support/image/TensorImage.java
index 2d57749b7c7..b19ef2e3b62 100644
--- a/tensorflow/lite/experimental/support/java/src/java/org/tensorflow/lite/support/image/TensorImage.java
+++ b/tensorflow/lite/experimental/support/java/src/java/org/tensorflow/lite/support/image/TensorImage.java
@@ -28,16 +28,16 @@ import org.tensorflow.lite.support.tensorbuffer.TensorBuffer;
  * TFLite.support library, it's common to convert image objects in variant types to TensorImage at
  * first.
  *
- * <p>We are adopting a little bit complex strategy to keep data here. In short, a TensorImage
- * object may have 2 potential sources of truth: the real and updated image could be in a Bitmap, or
- * a TensorBuffer, or both. It's mainly for performance, avoiding redundant data conversions.
+ * <p>At present, only RGB images are supported, and the A channel is always ignored.
+ *
+ * <p>Details of data storage: a {@link TensorImage} object may have 2 potential sources of truth: a
+ * {@link Bitmap} or a {@link TensorBuffer}. {@link TensorImage} maintains the state and only
+ * convert one to the other when needed.
  *
  * <p>IMPORTANT: The container doesn't own its data. Callers should not modify data objects those
  * are passed to {@link ImageContainer#set(Bitmap)} or {@link ImageContainer#set(TensorBuffer)}.
  *
- * <p>IMPORTANT: All methods are not proved thread-safe. Note: This class still a WIP. Currently, it
- * supports only RGB color space in uint8 (0-255). When getting Bitmap, value of A channel is always
- * set by 0.
+ * <p>IMPORTANT: All methods are not proved thread-safe.
  *
  * @see ImageProcessor which is often used for transforming a {@link TensorImage}.
  */
@@ -79,6 +79,18 @@ public class TensorImage {
     container = new ImageContainer(dataType);
   }
 
+  /**
+   * Initializes a {@link TensorImage} object with a {@link Bitmap}.
+   *
+   * @see TensorImage#load(Bitmap) for reusing the object when it's expensive to create objects
+   *     frequently, because every call of {@code fromBitmap} creates a new {@link TensorImage}.
+   */
+  public static TensorImage fromBitmap(Bitmap bitmap) {
+    TensorImage image = new TensorImage();
+    image.load(bitmap);
+    return image;
+  }
+
   /**
    * Creates a deep-copy of a given {@link TensorImage} and converts internal tensor data type.
    *
@@ -171,7 +183,7 @@ public class TensorImage {
    * <p>Important: It's only a reference. DO NOT MODIFY. We don't create a copy here for performance
    * concern, but if modification is necessary, please make a copy.
    *
-   * @return a reference to a Bitmap representing the image in ARGB_8888 config. A is always 0.
+   * @return a reference to a Bitmap in ARGB_8888 config. "A" channel is always opaque.
    * @throws IllegalStateException if the TensorImage never loads data, or if the TensorImage is
    *     holding a float-value image in {@code TensorBuffer}.
    */