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)
diff --git a/libs/hwui/renderthread/CanvasContext.cpp b/libs/hwui/renderthread/CanvasContext.cpp
index 6b2c995..1b9d41a7 100644
--- a/libs/hwui/renderthread/CanvasContext.cpp
+++ b/libs/hwui/renderthread/CanvasContext.cpp
@@ -871,6 +871,10 @@
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 3f25339..d7215de 100644
--- a/libs/hwui/renderthread/CanvasContext.h
+++ b/libs/hwui/renderthread/CanvasContext.h
@@ -200,6 +200,9 @@
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 c68fcdf..9ebad81 100644
--- a/libs/hwui/renderthread/IRenderPipeline.h
+++ b/libs/hwui/renderthread/IRenderPipeline.h
@@ -97,6 +97,7 @@
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 21b6c44..a8da04b 100644
--- a/libs/hwui/renderthread/VulkanSurface.cpp
+++ b/libs/hwui/renderthread/VulkanSurface.cpp
@@ -63,6 +63,18 @@
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 @@
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 @@
}
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 e2ddc6b..6f528010 100644
--- a/libs/hwui/renderthread/VulkanSurface.h
+++ b/libs/hwui/renderthread/VulkanSurface.h
@@ -47,6 +47,7 @@
const SkMatrix& getCurrentPreTransform() { return mWindowInfo.preTransform; }
void setColorSpace(sk_sp<SkColorSpace> colorSpace);
+ const SkM44& getPixelSnapMatrix() const { return mWindowInfo.pixelSnapMatrix; }
private:
/*
@@ -105,6 +106,7 @@
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);