[graphite] Check miter limit for stroked rects
I had a flawed understanding of the miter limit and thought it's min
allowed value was sqrt(2) so 90 degree corners would never be a bevel.
That's not the case so this checks the miter limit before uploading the
final join style to the instance data.
I also noticed that the stroke_rect_shader GM was setting the miter
limit on the paint and then drawing a second row, so on the second
time through the original full-miter draw was still seeing the very
small miter limit and was becoming beveled. This is fixed so the
miter column matches across AA and non-AA.
I confirmed that in Graphite, the beveled-miter column now draws with
bevels instead of mitered.
Bug: b/266451994
Change-Id: Ia8f3a4d7c9ddb9b9b34f933d0787b967181e07c2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/645040
Commit-Queue: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
Auto-Submit: Michael Ludwig <michaelludwig@google.com>
diff --git a/gm/stroke_rect_shader.cpp b/gm/stroke_rect_shader.cpp
index 1e97014..6a57030 100644
--- a/gm/stroke_rect_shader.cpp
+++ b/gm/stroke_rect_shader.cpp
@@ -29,17 +29,19 @@
constexpr SkRect kRect {0, 0, 100, 100};
constexpr SkPoint kPts[] {{kRect.fLeft, kRect.fTop}, {kRect.fRight, kRect.fBottom}};
constexpr SkColor kColors[] {SK_ColorRED, SK_ColorBLUE};
- SkPaint paint;
sk_sp<SkShader> shader = SkGradientShader::MakeLinear(kPts, kColors, nullptr, 2,
SkTileMode::kClamp);
- paint.setShader(std::move(shader));
- paint.setStyle(SkPaint::kStroke_Style);
+
// Do a large initial translate so that local coords disagree with device coords significantly
// for the first rect drawn.
canvas->translate(kRect.centerX(), kRect.centerY());
constexpr SkScalar kPad = 20;
for (auto aa : {false, true}) {
+ SkPaint paint;
+ paint.setShader(shader);
+ paint.setStyle(SkPaint::kStroke_Style);
paint.setAntiAlias(aa);
+
canvas->save();
constexpr SkScalar kStrokeWidth = 10;
diff --git a/src/gpu/graphite/render/AnalyticRRectRenderStep.cpp b/src/gpu/graphite/render/AnalyticRRectRenderStep.cpp
index 515ec81..217821d 100644
--- a/src/gpu/graphite/render/AnalyticRRectRenderStep.cpp
+++ b/src/gpu/graphite/render/AnalyticRRectRenderStep.cpp
@@ -762,9 +762,14 @@
if (params.strokeStyle().halfWidth() > 0.f) {
float joinStyle = params.strokeStyle().joinLimit();
if (params.strokeStyle().isMiterJoin()) {
- // Discard actual miter limit because a 90-degree corner never exceeds that, and
- // set either +1 for per-corner mitering or +2 for if all corners are mitered.
- joinStyle = all(xRadii == skvx::float4(0.f)) ? 2.f : 1.f;
+ // All corners are 90-degrees so become beveled if the miter limit is < sqrt(2).
+ if (params.strokeStyle().miterLimit() < SK_ScalarSqrt2) {
+ joinStyle = 0.f; // == bevel
+ } else {
+ // Discard actual miter limit because a 90-degree corner never exceeds that, and
+ // set either +1 for per-corner mitering or +2 for if all corners are mitered.
+ joinStyle = all(xRadii == skvx::float4(0.f)) ? 2.f : 1.f;
+ }
}
// Write a negative value outside [-1, 0] to signal a stroked shape, then the style
// params, followed by corner radii and bounds.
