fix hairline clip

src/core/SkScan_Hairline.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkScan.h"
 #include "SkBlitter.h"
 #include "SkRasterClip.h"
@@ skipping 196 matching lines @@
     int idx = SkScalarCeilToInt(dx);
     int idy = SkScalarCeilToInt(dy);
     // use the cheap approx for distance
     if (idx > idy) {
         return idx + (idy >> 1);
     } else {
         return idy + (idx >> 1);
     }
 }
 
-static void hairquad(const SkPoint pts[3], const SkRegion* clip,
+static void hair_quad(const SkPoint pts[3], const SkRegion* clip,
                      SkBlitter* blitter, int level, SkScan::HairRgnProc lineproc) {
     SkASSERT(level <= kMaxQuadSubdivideLevel);
 
     SkQuadCoeff coeff(pts);
 
     const int lines = 1 << level;
     Sk2s t(0);
     Sk2s dt(SK_Scalar1 / lines);
 
     SkPoint tmp[(1 << kMaxQuadSubdivideLevel) + 1];
     SkASSERT((unsigned)lines < SK_ARRAY_COUNT(tmp));
 
     tmp[0] = pts[0];
     Sk2s A = coeff.fA;
     Sk2s B = coeff.fB;
     Sk2s C = coeff.fC;
     for (int i = 1; i < lines; ++i) {
         t = t + dt;
         ((A * t + B) * t + C).store(&tmp[i]);
     }
     tmp[lines] = pts[2];
     lineproc(tmp, lines + 1, clip, blitter);
 }
 
+static SkRect compute_nocheck_quad_bounds(const SkPoint pts[3]) {
+        SkASSERT(SkScalarsAreFinite(&pts[0].fX, 8));
+
+        Sk2s min = Sk2s::Load(pts);
+        Sk2s max = min;
+        for (int i = 1; i < 3; ++i) {
+                Sk2s pair = Sk2s::Load(pts+i);
+                min = Sk2s::Min(min, pair);
+                max = Sk2s::Max(max, pair);
+}
+        return { min[0], min[1], max[0], max[1] };
+}
+
+static bool is_inverted(const SkRect& r) {
+        return r.fLeft > r.fRight || r.fTop > r.fBottom;
+}
+
+// Can't call SkRect::intersects, since it cares about empty, and we don't (since we tracking
+// something to be stroked, so empty can still draw something (e.g. horizontal line)
+static bool geometric_overlap(const SkRect& a, const SkRect& b) {
+        SkASSERT(!is_inverted(a) && !is_inverted(b));
+        return a.fLeft < b.fRight && b.fLeft < a.fRight &&
+                a.fTop < b.fBottom && b.fTop < a.fBottom;
+}
+
+// Can't call SkRect::contains, since it cares about empty, and we don't (since we tracking
+// something to be stroked, so empty can still draw something (e.g. horizontal line)
+static bool geometric_contains(const SkRect& outer, const SkRect& inner) {
+        SkASSERT(!is_inverted(outer) && !is_inverted(inner));
+        return inner.fRight <= outer.fRight && inner.fLeft >= outer.fLeft &&
+                inner.fBottom <= outer.fBottom && inner.fTop >= outer.fTop;
+}
+
+//#define SK_SHOW_HAIRCLIP_STATS
+#ifdef SK_SHOW_HAIRCLIP_STATS
+static int gKillClip, gRejectClip, gClipCount;
+#endif
+
+static inline void hairquad(const SkPoint pts[3], const SkRegion* clip, const SkRect* insetClip, const SkRect* outsetClip,
+        SkBlitter* blitter, int level, SkScan::HairRgnProc lineproc) {
+        if (insetClip) {
+                SkASSERT(outsetClip);
+#ifdef SK_SHOW_HAIRCLIP_STATS

[reed1, 2016/05/11 19:47:50]

I'm fine with these, or fine if we remove all this stats gathering code, since I
at least have not tested it in quite a while.

+                gClipCount += 1;
+#endif
+                SkRect bounds = compute_nocheck_quad_bounds(pts);
+                if (!geometric_overlap(*outsetClip, bounds)) {
+#ifdef SK_SHOW_HAIRCLIP_STATS
+                        gRejectClip += 1;
+#endif
+                        return;
+                } else if (geometric_contains(*insetClip, bounds)) {
+                        clip = nullptr;
+#ifdef SK_SHOW_HAIRCLIP_STATS
+                        gKillClip += 1;
+#endif
+                }
+#ifdef SK_SHOW_HAIRCLIP_STATS
+                if (0 == gClipCount % 256)
+                        SkDebugf("kill %g reject %g total %d\n", 1.0*gKillClip / gClipCount, 1.0*gRejectClip/gClipCount, gClipCount);
+#endif
+        }
+
+        hair_quad(pts, clip, blitter, level, lineproc);
+}
+
 static inline Sk2s abs(const Sk2s& value) {
     return Sk2s::Max(value, Sk2s(0)-value);
 }
 
 static inline SkScalar max_component(const Sk2s& value) {
     SkScalar components[2];
     value.store(components);
     return SkTMax(components[0], components[1]);
 }
 
@@ skipping 70 matching lines @@
     Sk2s min = Sk2s::Load(pts);
     Sk2s max = min;
     for (int i = 1; i < 4; ++i) {
         Sk2s pair = Sk2s::Load(pts+i);
         min = Sk2s::Min(min, pair);
         max = Sk2s::Max(max, pair);
     }
     return { min[0], min[1], max[0], max[1] };
 }
 
-static bool is_inverted(const SkRect& r) {
-    return r.fLeft > r.fRight || r.fTop > r.fBottom;
-}
-
-// Can't call SkRect::intersects, since it cares about empty, and we don't (since we tracking
-// something to be stroked, so empty can still draw something (e.g. horizontal line)
-static bool geometric_overlap(const SkRect& a, const SkRect& b) {
-    SkASSERT(!is_inverted(a) && !is_inverted(b));
-    return a.fLeft < b.fRight && b.fLeft < a.fRight &&
-           a.fTop < b.fBottom && b.fTop < a.fBottom;
-}
-
-// Can't call SkRect::contains, since it cares about empty, and we don't (since we tracking
-// something to be stroked, so empty can still draw something (e.g. horizontal line)
-static bool geometric_contains(const SkRect& outer, const SkRect& inner) {
-    SkASSERT(!is_inverted(outer) && !is_inverted(inner));
-    return inner.fRight <= outer.fRight && inner.fLeft >= outer.fLeft &&
-           inner.fBottom <= outer.fBottom && inner.fTop >= outer.fTop;
-}
-
-//#define SK_SHOW_HAIRCLIP_STATS
-#ifdef SK_SHOW_HAIRCLIP_STATS
-static int gKillClip, gRejectClip, gClipCount;
-#endif
-
 static inline void haircubic(const SkPoint pts[4], const SkRegion* clip, const SkRect* insetClip, const SkRect* outsetClip,
                       SkBlitter* blitter, int level, SkScan::HairRgnProc lineproc) {
     if (insetClip) {
         SkASSERT(outsetClip);
 #ifdef SK_SHOW_HAIRCLIP_STATS
         gClipCount += 1;
 #endif
         SkRect bounds = compute_nocheck_cubic_bounds(pts);
         if (!geometric_overlap(*outsetClip, bounds)) {
 #ifdef SK_SHOW_HAIRCLIP_STATS
@@ skipping 138 matching lines @@
             insetStorage.inset(1, 1);
             if (is_inverted(insetStorage)) {
                 /*
                  *  our bounds checks assume the rects are never inverted. If insetting has
                  *  created that, we assume that the area is too small to safely perform a
                  *  quick-accept, so we just mark the rect as empty (so the quick-accept check
                  *  will always fail.
                  */
                 insetStorage.setEmpty();    // just so we don't pass an inverted rect
             }
-            insetClip = &insetStorage;
+                        if (rclip.isRect()) {

[reed1, 2016/05/11 19:47:50]

funny indenting (tabs?)

+                                insetClip = &insetStorage;
+                        }
             outsetClip = &outsetStorage;
         }
     }
 
     SkPath::RawIter     iter(path);
     SkPoint             pts[4], firstPt, lastPt;
     SkPath::Verb        verb, prevVerb;
     SkAutoConicToQuads  converter;
 
     if (SkPaint::kButt_Cap != capStyle) {
         prevVerb = SkPath::kDone_Verb;
     }
     while ((verb = iter.next(pts)) != SkPath::kDone_Verb) {
         switch (verb) {
             case SkPath::kMove_Verb:
                 firstPt = lastPt = pts[0];
                 break;
             case SkPath::kLine_Verb:
                 if (SkPaint::kButt_Cap != capStyle) {
                     extend_pts<capStyle>(prevVerb, iter.peek(), pts, 2);
                 }
                 lineproc(pts, 2, clip, blitter);
                 lastPt = pts[1];
                 break;
             case SkPath::kQuad_Verb:
                 if (SkPaint::kButt_Cap != capStyle) {
                     extend_pts<capStyle>(prevVerb, iter.peek(), pts, 3);
                 }
-                hairquad(pts, clip, blitter, compute_quad_level(pts), lineproc);
+                hairquad(pts, clip, insetClip, outsetClip, blitter, compute_quad_level(pts), lineproc);
                 lastPt = pts[2];
                 break;
             case SkPath::kConic_Verb: {
                 if (SkPaint::kButt_Cap != capStyle) {
                     extend_pts<capStyle>(prevVerb, iter.peek(), pts, 3);
                 }
                 // how close should the quads be to the original conic?
                 const SkScalar tol = SK_Scalar1 / 4;
                 const SkPoint* quadPts = converter.computeQuads(pts,
                                                        iter.conicWeight(), tol);
                 for (int i = 0; i < converter.countQuads(); ++i) {
                     int level = compute_quad_level(quadPts);
-                    hairquad(quadPts, clip, blitter, level, lineproc);
+                    hairquad(quadPts, clip, insetClip, outsetClip, blitter, level, lineproc);
                     quadPts += 2;
                 }
                 lastPt = pts[2];
                 break;
             }
             case SkPath::kCubic_Verb: {
                 if (SkPaint::kButt_Cap != capStyle) {
                     extend_pts<capStyle>(prevVerb, iter.peek(), pts, 4);
                 }
                 haircubic(pts, clip, insetClip, outsetClip, blitter, kMaxCubicSubdivideLevel, lineproc);
@@ skipping 111 matching lines @@
 
         SkAAClipBlitterWrapper wrap;
         if (!clip.quickContains(r.roundOut().makeOutset(1, 1))) {
             wrap.init(clip, blitter);
             blitter = wrap.getBlitter();
             clipRgn = &wrap.getRgn();
         }
         AntiHairLineRgn(pts, count, clipRgn, blitter);
     }
 }