From 3d1a6bc5f3124dd5cd237ccc39ead26fe4b3355f Mon Sep 17 00:00:00 2001
From: Florin Malita <fmalita@chromium.org>
Date: Thu, 9 Feb 2017 15:05:15 -0500
Subject: [4fGradient] Relax interval checks for SkGradientShaderBase also

Similar to https://skia-review.googlesource.com/8270, treat intervals
as closed at both extremities in the 4f gradient fallback impl also.

BUG=skia:6212

Change-Id: I7f164868202ae6a0f76cbcdbcbf8e62db12a1bd4
Reviewed-on: https://skia-review.googlesource.com/8277
Commit-Queue: Florin Malita <fmalita@chromium.org>
Reviewed-by: Mike Reed <reed@google.com>
---
 src/effects/gradients/Sk4fGradientBase.cpp | 18 +++++++++---------
 src/effects/gradients/Sk4fGradientBase.h   |  7 +++++++
 2 files changed, 16 insertions(+), 9 deletions(-)

(limited to 'src/effects/gradients')

diff --git a/src/effects/gradients/Sk4fGradientBase.cpp b/src/effects/gradients/Sk4fGradientBase.cpp
index 91f418564f..e234e9bc36 100644
--- a/src/effects/gradients/Sk4fGradientBase.cpp
+++ b/src/effects/gradients/Sk4fGradientBase.cpp
@@ -360,7 +360,7 @@ public:
             // TODO: maybe do this in ctor to remove a branch?
             fInterval = this->findFirstInterval(tiled_t);
             this->loadIntervalData(fInterval);
-        } else if (tiled_t < fInterval->fP0 || tiled_t >= fInterval->fP1) {
+        } else if (!fInterval->contains(tiled_t)) {
             fInterval = this->findNextInterval(t, tiled_t);
             this->loadIntervalData(fInterval);
         }
@@ -391,7 +391,7 @@ private:
     }
 
     Sk4f lerp(SkScalar t) {
-        SkASSERT(t >= fInterval->fP0 && t < fInterval->fP1);
+        SkASSERT(fInterval->contains(t));
         return fCc + fDc * (t - fInterval->fP0);
     }
 
@@ -402,24 +402,24 @@ private:
 
         while (i0 != i1) {
             SkASSERT(i0 < i1);
-            SkASSERT(t >= i0->fP0 && t < i1->fP1);
+            SkASSERT(t >= i0->fP0 && t <= i1->fP1);
 
             const Interval* i = i0 + ((i1 - i0) >> 1);
 
-            if (t >= i->fP1) {
+            if (t > i->fP1) {
                 i0 = i + 1;
             } else {
                 i1 = i;
             }
         }
 
-        SkASSERT(t >= i0->fP0 && t <= i0->fP1);
+        SkASSERT(i0->contains(t));
         return i0;
     }
 
     const Interval* findNextInterval(SkScalar t, SkScalar tiled_t) const {
-        SkASSERT(tiled_t < fInterval->fP0 || tiled_t >= fInterval->fP1);
-        SkASSERT(tiled_t >= fFirstInterval->fP0 && tiled_t < fLastInterval->fP1);
+        SkASSERT(!fInterval->contains(tiled_t));
+        SkASSERT(tiled_t >= fFirstInterval->fP0 && tiled_t <= fLastInterval->fP1);
 
         const Interval* i = fInterval;
 
@@ -431,14 +431,14 @@ private:
                 if (i > fLastInterval) {
                     i = fFirstInterval;
                 }
-            } while (tiled_t < i->fP0 || tiled_t >= i->fP1);
+            } while (!i->contains(tiled_t));
         } else {
             do {
                 i -= 1;
                 if (i < fFirstInterval) {
                     i = fLastInterval;
                 }
-            } while (tiled_t < i->fP0 || tiled_t >= i->fP1);
+            } while (!i->contains(tiled_t));
         }
 
         return i;
diff --git a/src/effects/gradients/Sk4fGradientBase.h b/src/effects/gradients/Sk4fGradientBase.h
index fa8412ce2a..6d0c3b96ff 100644
--- a/src/effects/gradients/Sk4fGradientBase.h
+++ b/src/effects/gradients/Sk4fGradientBase.h
@@ -37,6 +37,13 @@ protected:
 
         bool isZeroRamp() const { return fZeroRamp; }
 
+        bool contains(SkScalar p) const {
+            // True if p is in [p0,p1].  Note: this helper assumes a
+            // natural/increasing interval - so it's not usable in Sk4fLinearGradient.
+            SkASSERT(fP0 < fP1);
+            return p >= fP0 && p <= fP1;
+        }
+
         SkPM4f   fC0, fDc;
         SkScalar fP0, fP1;
         bool     fZeroRamp;
-- 
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