From fbc066e0a21c6381a0c8a1dd2d5175fd9a8f28ad Mon Sep 17 00:00:00 2001
From: Alexey Ushakov <avu@openjdk.org>
Date: Wed, 21 Oct 2020 20:08:48 +0000
Subject: [PATCH] 8255149: Lanai:
 DrawImage/IncorrectAlphaConversionBicubic.java failure

---
 src/java.desktop/macosx/native/libawt_lwawt/awt/common.h      | 1 +
 src/java.desktop/macosx/native/libawt_lwawt/awt/shaders.metal | 4 ++++
 .../macosx/native/libawt_lwawt/java2d/metal/MTLPaints.m       | 4 +++-
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/java.desktop/macosx/native/libawt_lwawt/awt/common.h b/src/java.desktop/macosx/native/libawt_lwawt/awt/common.h
index a00227c00e7..0053d0ceeb3 100644
--- a/src/java.desktop/macosx/native/libawt_lwawt/awt/common.h
+++ b/src/java.desktop/macosx/native/libawt_lwawt/awt/common.h
@@ -102,6 +102,7 @@ struct TxtFrameUniforms {
     vector_float4 color;
     int mode; // NOTE: consider to use bit fields
     int isSrcOpaque;
+    int isSrcPremult;
     int isDstOpaque;
     float extraAlpha;
 };
diff --git a/src/java.desktop/macosx/native/libawt_lwawt/awt/shaders.metal b/src/java.desktop/macosx/native/libawt_lwawt/awt/shaders.metal
index 64b377e104c..b944c74cb15 100644
--- a/src/java.desktop/macosx/native/libawt_lwawt/awt/shaders.metal
+++ b/src/java.desktop/macosx/native/libawt_lwawt/awt/shaders.metal
@@ -177,6 +177,10 @@ fragment half4 frag_txt(
         return half4(c.r, c.g, c.b , c.a);
     }
 
+    if (uniforms.isSrcPremult) {
+        pixelColor.rgb /= srcA;
+    }
+
     return half4(pixelColor.r,
                  pixelColor.g,
                  pixelColor.b, srcA)*uniforms.extraAlpha;
diff --git a/src/java.desktop/macosx/native/libawt_lwawt/java2d/metal/MTLPaints.m b/src/java.desktop/macosx/native/libawt_lwawt/java2d/metal/MTLPaints.m
index 26675398cfc..49dad8b9b65 100644
--- a/src/java.desktop/macosx/native/libawt_lwawt/java2d/metal/MTLPaints.m
+++ b/src/java.desktop/macosx/native/libawt_lwawt/java2d/metal/MTLPaints.m
@@ -858,7 +858,9 @@ static void setTxtUniforms(
         id<MTLRenderCommandEncoder> encoder, int color, int mode, int interpolation, bool repeat, jfloat extraAlpha,
         const SurfaceRasterFlags * srcFlags, const SurfaceRasterFlags * dstFlags
 ) {
-    struct TxtFrameUniforms uf = {RGBA_TO_V4(color), mode, srcFlags->isOpaque, dstFlags->isOpaque, extraAlpha};
+    struct TxtFrameUniforms uf = {
+      RGBA_TO_V4(color), mode, srcFlags->isOpaque, srcFlags->isPremultiplied,
+      dstFlags->isOpaque, extraAlpha};
     [encoder setFragmentBytes:&uf length:sizeof(uf) atIndex:FrameUniformBuffer];
 
     setSampler(encoder, interpolation, repeat);