Fix radii calculation

src/core/SkRRect.cpp

Index: src/core/SkRRect.cpp
diff --git a/src/core/SkRRect.cpp b/src/core/SkRRect.cpp
index ad62e5bbae82947d337c977ba218e0e9ece53348..ca4fd561523f345b0f9b889c09ea5f44b13c628a 100644
--- a/src/core/SkRRect.cpp
+++ b/src/core/SkRRect.cpp
@@ -5,8 +5,10 @@
  * found in the LICENSE file.
  */
 
+#include <cmath>
 #include "SkRRect.h"
 #include "SkMatrix.h"
+#include "SkScaleToSides.h"
 
 ///////////////////////////////////////////////////////////////////////////////
 
@@ -109,28 +111,6 @@ void SkRRect::setNinePatch(const SkRect& rect, SkScalar leftRad, SkScalar topRad
     SkDEBUGCODE(this->validate();)
 }
 
-/*
- *  TODO: clean this guy up and possibly add to SkScalar.h
- */
-static inline SkScalar SkScalarDecULP(SkScalar value) {
-#if SK_SCALAR_IS_FLOAT
-        return SkBits2Float(SkFloat2Bits(value) - 1);
-#else
-    #error "need impl for doubles"
-#endif
-}
-
- /**
- *  We need all combinations of predicates to be true to have a "safe" radius value.
- */
-static SkScalar clamp_radius_check_predicates(SkScalar rad, SkScalar min, SkScalar max) {
-    SkASSERT(min < max);
-    if (rad > max - min || min + rad > max || max - rad < min) {
-        rad = SkScalarDecULP(rad);
-    }
-    return rad;
-}
-
 // These parameters intentionally double. Apropos crbug.com/463920, if one of the
 // radii is huge while the other is small, single precision math can completely
 // miss the fact that a scale is required.
@@ -190,29 +170,21 @@ void SkRRect::setRectRadii(const SkRect& rect, const SkVector radii[4]) {
     // If f < 1, then all corner radii are reduced by multiplying them by f."
     double scale = 1.0;
 
-    scale = compute_min_scale(fRadii[0].fX, fRadii[1].fX, fRect.width(),  scale);
-    scale = compute_min_scale(fRadii[1].fY, fRadii[2].fY, fRect.height(), scale);
-    scale = compute_min_scale(fRadii[2].fX, fRadii[3].fX, fRect.width(),  scale);
-    scale = compute_min_scale(fRadii[3].fY, fRadii[0].fY, fRect.height(), scale);
+    // The sides of the rectangle may be larger than a float.
+    double width = (double)fRect.fRight - (double)fRect.fLeft;
+    double height = (double)fRect.fBottom - (double)fRect.fTop;
+    scale = compute_min_scale(fRadii[0].fX, fRadii[1].fX, width,  scale);
+    scale = compute_min_scale(fRadii[1].fY, fRadii[2].fY, height, scale);
+    scale = compute_min_scale(fRadii[2].fX, fRadii[3].fX, width,  scale);
+    scale = compute_min_scale(fRadii[3].fY, fRadii[0].fY, height, scale);
 
     if (scale < 1.0) {
-        for (int i = 0; i < 4; ++i) {
-            fRadii[i].fX *= scale;
-            fRadii[i].fY *= scale;
-        }
+        ScaleToSides::AdjustRadii(width,  scale, &fRadii[0].fX, &fRadii[1].fX);
+        ScaleToSides::AdjustRadii(height, scale, &fRadii[1].fY, &fRadii[2].fY);
+        ScaleToSides::AdjustRadii(width,  scale, &fRadii[2].fX, &fRadii[3].fX);
+        ScaleToSides::AdjustRadii(height, scale, &fRadii[3].fY, &fRadii[0].fY);
     }
 
-    // https://bug.skia.org/3239 -- its possible that we can hit the following inconsistency:
-    //     rad == bounds.bottom - bounds.top
-    //     bounds.bottom - radius < bounds.top
-    //     YIKES
-    // We need to detect and "fix" this now, otherwise we can have the following wackiness:
-    //     path.addRRect(rrect);
-    //     rrect.rect() != path.getBounds()
-    for (int i = 0; i < 4; ++i) {
-        fRadii[i].fX = clamp_radius_check_predicates(fRadii[i].fX, fRect.fLeft, fRect.fRight);
-        fRadii[i].fY = clamp_radius_check_predicates(fRadii[i].fY, fRect.fTop, fRect.fBottom);
-    }
     // At this point we're either oval, simple, or complex (not empty or rect).
     this->computeType();