Explain why Bitmap#setColorSpace is @NonNull

Bug: 127282638
Test: No change in behavior
Change-Id: I167893b1d80ae37982804ec0dfa98b68d6eaab53

1 files changed, 5 insertions, 0 deletions

diff --git a/graphics/java/android/graphics/Bitmap.java b/graphics/java/android/graphics/Bitmap.java
index 18eafa61aa48..2e56e09522e9 100644
--- a/graphics/java/android/graphics/Bitmap.java
+++ b/graphics/java/android/graphics/Bitmap.java
@@ -1718,6 +1718,11 @@ public final class Bitmap implements Parcelable {
      * <p>Modifies the bitmap to have the specified {@link ColorSpace}, without
      * affecting the underlying allocation backing the bitmap.</p>
      *
+     * <p>This affects how the framework will interpret the color at each pixel. A bitmap
+     * with {@link Config#ALPHA_8} never has a color space, since a color space does not
+     * affect the alpha channel. Other {@code Config}s must always have a non-null
+     * {@code ColorSpace}.</p>
+     *
      * @throws IllegalArgumentException If the specified color space is {@code null}, not
      *         {@link ColorSpace.Model#RGB RGB}, has a transfer function that is not an
      *         {@link ColorSpace.Rgb.TransferParameters ICC parametric curve}, or whose