RESTRICT AUTOMERGE Add 1/16th pixel offset when drawing non-AA points/lines

This nudge ensures that pixel-aligned non-AA'd draws fill the desired
fragment.

Coupled with http://review.skia.org/665816, we're moving this logic from
Skia to Android so that the prerotation matrix can be properly accounted
for. Offseting only in Skia without accounting for prerotation  meant
the device-space Y offset could be applied in the wrong direction when
using Vulkan.

Equivalent change in T: Idfb5027fe3230f2c2b0cad224f2c7640e147ce4a

Bug: 254771190
Test: android.uirendering.cts.testclasses.ExactCanvasTests#testDrawLine
Change-Id: I975b62510a36312a395d1e254474bca726a9445d
(cherry picked from commit 7f785ebd57cf129bb39e89237fba541912ce3649)

9 files changed, 54 insertions, 1 deletions

diff --git a/libs/hwui/RecordingCanvas.cpp b/libs/hwui/RecordingCanvas.cpp
index 0b58406516e3..924fbd659824 100644
--- a/libs/hwui/RecordingCanvas.cpp
+++ b/libs/hwui/RecordingCanvas.cpp
@@ -51,6 +51,9 @@
 #include "include/gpu/GrDirectContext.h"
 #include "pipeline/skia/AnimatedDrawables.h"
 #include "pipeline/skia/FunctorDrawable.h"
+#ifdef __ANDROID__
+#include "renderthread/CanvasContext.h"
+#endif
 
 namespace android {
 namespace uirenderer {
@@ -489,7 +492,19 @@ struct DrawPoints final : Op {
     size_t count;
     SkPaint paint;
     void draw(SkCanvas* c, const SkMatrix&) const {
-        c->drawPoints(mode, count, pod<SkPoint>(this), paint);
+        if (paint.isAntiAlias()) {
+            c->drawPoints(mode, count, pod<SkPoint>(this), paint);
+        } else {
+            c->save();
+#ifdef __ANDROID__
+            auto pixelSnap = renderthread::CanvasContext::getActiveContext()->getPixelSnapMatrix();
+            auto transform = c->getLocalToDevice();
+            transform.postConcat(pixelSnap);
+            c->setMatrix(transform);
+#endif
+            c->drawPoints(mode, count, pod<SkPoint>(this), paint);
+            c->restore();
+        }
     }
 };
 struct DrawVertices final : Op {
diff --git a/libs/hwui/pipeline/skia/SkiaOpenGLPipeline.h b/libs/hwui/pipeline/skia/SkiaOpenGLPipeline.h
index 940d6bfdb83c..f0461bef170c 100644
--- a/libs/hwui/pipeline/skia/SkiaOpenGLPipeline.h
+++ b/libs/hwui/pipeline/skia/SkiaOpenGLPipeline.h
@@ -53,6 +53,14 @@ public:
     bool isSurfaceReady() override;
     bool isContextReady() override;
 
+    const SkM44& getPixelSnapMatrix() const override {
+        // Small (~1/16th) nudge to ensure that pixel-aligned non-AA'd draws fill the
+        // desired fragment
+        static const SkScalar kOffset = 0.063f;
+        static const SkM44 sSnapMatrix = SkM44::Translate(kOffset, kOffset);
+        return sSnapMatrix;
+    }
+
     static void invokeFunctor(const renderthread::RenderThread& thread, Functor* functor);
 
 protected:
diff --git a/libs/hwui/pipeline/skia/SkiaVulkanPipeline.cpp b/libs/hwui/pipeline/skia/SkiaVulkanPipeline.cpp
index c8f2e69ae0a4..86096d5bd01c 100644
--- a/libs/hwui/pipeline/skia/SkiaVulkanPipeline.cpp
+++ b/libs/hwui/pipeline/skia/SkiaVulkanPipeline.cpp
@@ -210,6 +210,10 @@ void SkiaVulkanPipeline::onContextDestroyed() {
     }
 }
 
+const SkM44& SkiaVulkanPipeline::getPixelSnapMatrix() const {
+    return mVkSurface->getPixelSnapMatrix();
+}
+
 } /* namespace skiapipeline */
 } /* namespace uirenderer */
 } /* namespace android */
diff --git a/libs/hwui/pipeline/skia/SkiaVulkanPipeline.h b/libs/hwui/pipeline/skia/SkiaVulkanPipeline.h
index d921ddb0d0fb..c0897398ac55 100644
--- a/libs/hwui/pipeline/skia/SkiaVulkanPipeline.h
+++ b/libs/hwui/pipeline/skia/SkiaVulkanPipeline.h
@@ -55,6 +55,7 @@ public:
     bool isContextReady() override;
     bool supportsExtendedRangeHdr() const override { return true; }
     void setTargetSdrHdrRatio(float ratio) override;
+    const SkM44& getPixelSnapMatrix() const override;
 
     static void invokeFunctor(const renderthread::RenderThread& thread, Functor* functor);
     static sk_sp<Bitmap> allocateHardwareBitmap(renderthread::RenderThread& thread,
diff --git a/libs/hwui/renderthread/CanvasContext.cpp b/libs/hwui/renderthread/CanvasContext.cpp
index 6b2c99534a4c..1b9d41a73f46 100644
--- a/libs/hwui/renderthread/CanvasContext.cpp
+++ b/libs/hwui/renderthread/CanvasContext.cpp
@@ -871,6 +871,10 @@ SkISize CanvasContext::getNextFrameSize() const {
     return size;
 }
 
+const SkM44& CanvasContext::getPixelSnapMatrix() const {
+    return mRenderPipeline->getPixelSnapMatrix();
+}
+
 void CanvasContext::prepareAndDraw(RenderNode* node) {
     ATRACE_CALL();
 
diff --git a/libs/hwui/renderthread/CanvasContext.h b/libs/hwui/renderthread/CanvasContext.h
index 3f2533959c20..d7215de92375 100644
--- a/libs/hwui/renderthread/CanvasContext.h
+++ b/libs/hwui/renderthread/CanvasContext.h
@@ -200,6 +200,9 @@ public:
 
     SkISize getNextFrameSize() const;
 
+    // Returns the matrix to use to nudge non-AA'd points/lines towards the fragment center
+    const SkM44& getPixelSnapMatrix() const;
+
     // Called when SurfaceStats are available.
     static void onSurfaceStatsAvailable(void* context, int32_t surfaceControlId,
                                         ASurfaceControlStats* stats);
diff --git a/libs/hwui/renderthread/IRenderPipeline.h b/libs/hwui/renderthread/IRenderPipeline.h
index c68fcdfc76f2..9ebad81c5c81 100644
--- a/libs/hwui/renderthread/IRenderPipeline.h
+++ b/libs/hwui/renderthread/IRenderPipeline.h
@@ -97,6 +97,7 @@ public:
 
     virtual bool supportsExtendedRangeHdr() const { return false; }
     virtual void setTargetSdrHdrRatio(float ratio) = 0;
+    virtual const SkM44& getPixelSnapMatrix() const = 0;
 
     virtual ~IRenderPipeline() {}
 };
diff --git a/libs/hwui/renderthread/VulkanSurface.cpp b/libs/hwui/renderthread/VulkanSurface.cpp
index 21b6c44e997e..a8da04b7240b 100644
--- a/libs/hwui/renderthread/VulkanSurface.cpp
+++ b/libs/hwui/renderthread/VulkanSurface.cpp
@@ -63,6 +63,18 @@ static SkMatrix GetPreTransformMatrix(SkISize windowSize, int transform) {
     return SkMatrix::I();
 }
 
+static SkM44 GetPixelSnapMatrix(SkISize windowSize, int transform) {
+    // Small (~1/16th) nudge to ensure that pixel-aligned non-AA'd draws fill the
+    // desired fragment
+    static const SkScalar kOffset = 0.063f;
+    SkMatrix preRotation = GetPreTransformMatrix(windowSize, transform);
+    SkMatrix invert;
+    LOG_ALWAYS_FATAL_IF(!preRotation.invert(&invert));
+    return SkM44::Translate(kOffset, kOffset)
+            .postConcat(SkM44(preRotation))
+            .preConcat(SkM44(invert));
+}
+
 static bool ConnectAndSetWindowDefaults(ANativeWindow* window) {
     ATRACE_CALL();
 
@@ -178,6 +190,8 @@ bool VulkanSurface::InitializeWindowInfoStruct(ANativeWindow* window, ColorMode
 
     outWindowInfo->preTransform =
             GetPreTransformMatrix(outWindowInfo->size, outWindowInfo->transform);
+    outWindowInfo->pixelSnapMatrix =
+            GetPixelSnapMatrix(outWindowInfo->size, outWindowInfo->transform);
 
     err = window->query(window, NATIVE_WINDOW_MIN_UNDEQUEUED_BUFFERS, &query_value);
     if (err != 0 || query_value < 0) {
@@ -413,6 +427,7 @@ VulkanSurface::NativeBufferInfo* VulkanSurface::dequeueNativeBuffer() {
         }
 
         mWindowInfo.preTransform = GetPreTransformMatrix(mWindowInfo.size, mWindowInfo.transform);
+        mWindowInfo.pixelSnapMatrix = GetPixelSnapMatrix(mWindowInfo.size, mWindowInfo.transform);
     }
 
     uint32_t idx;
diff --git a/libs/hwui/renderthread/VulkanSurface.h b/libs/hwui/renderthread/VulkanSurface.h
index e2ddc6b07768..6f5280105e55 100644
--- a/libs/hwui/renderthread/VulkanSurface.h
+++ b/libs/hwui/renderthread/VulkanSurface.h
@@ -47,6 +47,7 @@ public:
     const SkMatrix& getCurrentPreTransform() { return mWindowInfo.preTransform; }
 
     void setColorSpace(sk_sp<SkColorSpace> colorSpace);
+    const SkM44& getPixelSnapMatrix() const { return mWindowInfo.pixelSnapMatrix; }
 
 private:
     /*
@@ -105,6 +106,7 @@ private:
         SkISize actualSize;
         // transform to be applied to the SkSurface to map the coordinates to the provided transform
         SkMatrix preTransform;
+        SkM44 pixelSnapMatrix;
     };
 
     VulkanSurface(ANativeWindow* window, const WindowInfo& windowInfo, GrDirectContext* grContext);