Improve correctness of SkiaCanvas::drawLayoutOnPath
Align glyph to a tangent touching SkPath in the midle of the
symbol. Previously wrong tangent crossing the path at the
beginning of the glyph was used.
Test: Ran the test app attached to the bug
Bug: 71525360
Change-Id: I310394d11e185de314f66a6b332f804188e42ed9
diff --git a/libs/hwui/SkiaCanvas.cpp b/libs/hwui/SkiaCanvas.cpp
index 13e1ebe..2e08670 100644
--- a/libs/hwui/SkiaCanvas.cpp
+++ b/libs/hwui/SkiaCanvas.cpp
@@ -765,7 +765,8 @@
for (size_t i = start; i < end; i++) {
glyphs[i - start] = layout.getGlyphId(i);
- float x = hOffset + layout.getX(i);
+ float halfWidth = layout.getCharAdvance(i) * 0.5f;
+ float x = hOffset + layout.getX(i) + halfWidth;
float y = vOffset + layout.getY(i);
SkPoint pos;
@@ -776,8 +777,8 @@
}
xform[i - start].fSCos = tan.x();
xform[i - start].fSSin = tan.y();
- xform[i - start].fTx = pos.x() - tan.y() * y;
- xform[i - start].fTy = pos.y() + tan.x() * y;
+ xform[i - start].fTx = pos.x() - tan.y() * y - halfWidth * tan.x();
+ xform[i - start].fTy = pos.y() + tan.x() * y - halfWidth * tan.y();
}
this->asSkCanvas()->drawTextRSXform(glyphs, sizeof(uint16_t) * N, xform, nullptr, paint);