1 files changed, 26 insertions, 1 deletions
diff --git a/libs/hwui/Gainmap.cpp b/libs/hwui/Gainmap.cpp
index 30f401ef5f01..ea955e25dc2f 100644
--- a/libs/hwui/Gainmap.cpp
+++ b/libs/hwui/Gainmap.cpp
@@ -15,12 +15,37 @@
  */
 #include "Gainmap.h"
 
+#include <SkBitmap.h>
+#include <SkCanvas.h>
+#include <SkColorFilter.h>
+#include <SkImagePriv.h>
+#include <SkPaint.h>
+
+#include "HardwareBitmapUploader.h"
+
 namespace android::uirenderer {
 
 sp<Gainmap> Gainmap::allocateHardwareGainmap(const sp<Gainmap>& srcGainmap) {
     auto gainmap = sp<Gainmap>::make();
     gainmap->info = srcGainmap->info;
-    const SkBitmap skSrcBitmap = srcGainmap->bitmap->getSkBitmap();
+    SkBitmap skSrcBitmap = srcGainmap->bitmap->getSkBitmap();
+    if (skSrcBitmap.info().colorType() == kAlpha_8_SkColorType &&
+        !HardwareBitmapUploader::hasAlpha8Support()) {
+        // The regular Bitmap::allocateHardwareBitmap will do a conversion that preserves channels,
+        // so alpha8 maps to the alpha channel of rgba. However, for gainmaps we will interpret
+        // the data of an rgba buffer differently as we'll only look at the rgb channels
+        // So we need to map alpha8 to rgbx_8888 essentially
+        SkBitmap bitmap;
+        bitmap.allocPixels(skSrcBitmap.info().makeColorType(kN32_SkColorType));
+        SkCanvas canvas(bitmap);
+        SkPaint paint;
+        const float alphaToOpaque[] = {0, 0, 0, 1, 0, 0, 0, 0, 1, 0,
+                                       0, 0, 0, 1, 0, 0, 0, 0, 0, 255};
+        paint.setColorFilter(SkColorFilters::Matrix(alphaToOpaque, SkColorFilters::Clamp::kNo));
+        canvas.drawImage(SkMakeImageFromRasterBitmap(skSrcBitmap, kNever_SkCopyPixelsMode), 0, 0,
+                         SkSamplingOptions{}, &paint);
+        skSrcBitmap = bitmap;
+    }
     sk_sp<Bitmap> skBitmap(Bitmap::allocateHardwareBitmap(skSrcBitmap));
     if (!skBitmap.get()) {
         return nullptr;