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son of path is rect bug

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This variation tricks SkPath::isRect by exploiting
that the implementation resets the point pointer to
process the close verb, and using the reset pointer
to walk over a series of points that don't move.

In addition to fixing this, rename variables to
make the line creation more obvious, since left,
right, and friends, are not the left and right.

R=robertphillips@google.com

Bug: 824145,skia:7792
Change-Id: If8ebbc3eedd270652670d6e111a5bc02e61f0eec
Reviewed-on: https://skia-review.googlesource.com/121122
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Cary Clark <caryclark@skia.org>
This commit is contained in:
Cary Clark 2018-04-12 14:00:24 -04:00 committed by Skia Commit-Bot
parent b809efbbfa
commit 88ba9710b5
3 changed files with 35 additions and 14 deletions
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15
gm/pathfill.cpp
View File

@ -509,4 +509,19 @@ DEF_SIMPLE_GM(bug7792, canvas, 600, 600) {
path.lineTo(75, 10);
path.close();
canvas->drawPath(path, p);
// from skbug.com/7792 comment 19
canvas->translate(200, 0);
path.reset();
path.moveTo(75, 75);
path.lineTo(75, 75);
path.lineTo(75, 75);
path.lineTo(75, 75);
path.lineTo(150, 75);
path.lineTo(150, 150);
path.lineTo(75, 150);
path.close();
path.moveTo(10, 10);
path.lineTo(30, 10);
path.lineTo(10, 30);
canvas->drawPath(path, p);
}

25
src/core/SkPath.cpp
View File

@ -446,15 +446,16 @@ FIXME: If the API passes fill-only, return true if the filled stroke
static int rect_make_dir(SkScalar dx, SkScalar dy) {
return ((0 != dx) << 0) | ((dx > 0 || dy > 0) << 1);
}
bool SkPath::isRectContour(bool allowPartial, int* currVerb, const SkPoint** ptsPtr,
bool* isClosed, Direction* direction, SkRect* rect) const {
int corners = 0;
SkPoint previous; // used to construct line from previous point
SkPoint lineStart; // used to construct line from previous point
const SkPoint* firstPt = nullptr; // first point in the rect (last of first moves)
const SkPoint* lastPt = nullptr; // last point in the rect (last of lines or first if closed)
const SkPoint* pts = *ptsPtr;
const SkPoint* savePts = nullptr; // used to allow caller to iterate through a pair of rects
previous.set(0, 0);
lineStart.set(0, 0);
int firstDirection = 0;
int lastDirection = 0;
int nextDirection = 0;
@ -469,30 +470,26 @@ bool SkPath::isRectContour(bool allowPartial, int* currVerb, const SkPoint** pts
switch (verb) {
case kClose_Verb:
savePts = pts;
pts = firstPt;
autoClose = true;
insertClose = false;
accumulatingRect = false;
case kLine_Verb: {
SkScalar left = previous.fX;
SkScalar top = previous.fY;
SkScalar right = pts->fX;
SkScalar bottom = pts->fY;
if (accumulatingRect) {
lastPt = pts;
}
++pts;
if (left != right && top != bottom) {
SkPoint lineEnd = kClose_Verb == verb ? *firstPt : *pts++;
SkVector lineDelta = lineEnd - lineStart;
if (lineDelta.fX && lineDelta.fY) {
return false; // diagonal
}
addedLine = true;
if (left == right && top == bottom) {
if (lineStart == lineEnd) {
break; // single point on side OK
}
nextDirection = rect_make_dir(right - left, bottom - top);
nextDirection = rect_make_dir(lineDelta.fX, lineDelta.fY);
if (0 == corners) {
firstDirection = nextDirection;
previous = pts[-1];
lineStart = lineEnd;
corners = 1;
closedOrMoved = false;
break;
@ -509,7 +506,7 @@ bool SkPath::isRectContour(bool allowPartial, int* currVerb, const SkPoint** pts
return false; // too many direction changes
}
}
previous = pts[-1];
lineStart = lineEnd;
if (lastDirection == nextDirection) {
break; // colinear segment
}
@ -539,7 +536,7 @@ bool SkPath::isRectContour(bool allowPartial, int* currVerb, const SkPoint** pts
} else {
accumulatingRect = false;
}
previous = *pts++;
lineStart = *pts++;
closedOrMoved = true;
break;
default:

9
tests/PathTest.cpp
View File

@ -4977,4 +4977,13 @@ DEF_TEST(Path_isRect, reporter) {
SkPoint points17[] = { {75, 10}, {75, 75}, {150, 75}, {150, 150}, {75, 150}, {75, 10} };
path = makePath(points17, SK_ARRAY_COUNT(points17), true);
REPORTER_ASSERT(reporter, !path.isRect(&rect, nullptr, nullptr));
// isolated from skbug.com/7792 comment 19
SkPath::Verb verbs19[] = { SkPath::kMove_Verb, SkPath::kLine_Verb, SkPath::kLine_Verb,
SkPath::kLine_Verb, SkPath::kLine_Verb, SkPath::kLine_Verb,
SkPath::kLine_Verb, SkPath::kClose_Verb, SkPath::kMove_Verb,
SkPath::kLine_Verb, SkPath::kLine_Verb };
SkPoint points19[] = { {75, 75}, {75, 75}, {75, 75}, {75, 75}, {150, 75}, {150, 150},
{75, 150}, {10, 10}, {30, 10}, {10, 30} };
path = makePath2(points19, verbs19, SK_ARRAY_COUNT(verbs19));
REPORTER_ASSERT(reporter, !path.isRect(&rect, nullptr, nullptr));
}