From d1b099c3e3cfcbf86353b53e205c0ebf84cf5592 Mon Sep 17 00:00:00 2001 From: Marc Mutz Date: Wed, 14 Aug 2019 09:41:18 +0200 Subject: QBezier: replace out parameters by return-by-value in split() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit At least QBezier itself is calling the old function with *this aliased to one of the arguments. Consequently, the implementation looks rather ... shuffled, to avoid writing into members that it will read once more later. Fix by returning a std::pair instead. This simplifies the code that doesn't actually pass existing objects in, and avoids aliasing problems cropping up under seemingly innocuous reorderings of statements in the implementation going forward. While I'm usually vehemently against use std::pair or std::tuple in APIs, preferring simple structs with aptly-named members instead, this is one case where the .first and .second actually fit, and pair allows us to use std::tie, which was handy in qbezier.cpp. This patch preserves the body of the function as much as possible. A follow-up patch will clean it up. Change-Id: I017dfee4a0e69a2e171ce21b89ba04654772c33d Reviewed-by: Edward Welbourne Reviewed-by: Mårten Nordheim --- src/gui/painting/qpainterpath.cpp | 21 +++++++++------------ 1 file changed, 9 insertions(+), 12 deletions(-) (limited to 'src/gui/painting/qpainterpath.cpp') diff --git a/src/gui/painting/qpainterpath.cpp b/src/gui/painting/qpainterpath.cpp index b1d1f30800..1fb37ece56 100644 --- a/src/gui/painting/qpainterpath.cpp +++ b/src/gui/painting/qpainterpath.cpp @@ -1855,10 +1855,9 @@ static void qt_painterpath_isect_curve(const QBezier &bezier, const QPointF &pt, } // split curve and try again... - QBezier first_half, second_half; - bezier.split(&first_half, &second_half); - qt_painterpath_isect_curve(first_half, pt, winding, depth + 1); - qt_painterpath_isect_curve(second_half, pt, winding, depth + 1); + const auto halves = bezier.split(); + qt_painterpath_isect_curve(halves.first, pt, winding, depth + 1); + qt_painterpath_isect_curve(halves.second, pt, winding, depth + 1); } } @@ -2013,10 +2012,9 @@ static bool qt_isect_curve_horizontal(const QBezier &bezier, qreal y, qreal x1, if (depth == 32 || (bounds.width() < lower_bound && bounds.height() < lower_bound)) return true; - QBezier first_half, second_half; - bezier.split(&first_half, &second_half); - if (qt_isect_curve_horizontal(first_half, y, x1, x2, depth + 1) - || qt_isect_curve_horizontal(second_half, y, x1, x2, depth + 1)) + const auto halves = bezier.split(); + if (qt_isect_curve_horizontal(halves.first, y, x1, x2, depth + 1) + || qt_isect_curve_horizontal(halves.second, y, x1, x2, depth + 1)) return true; } return false; @@ -2032,10 +2030,9 @@ static bool qt_isect_curve_vertical(const QBezier &bezier, qreal x, qreal y1, qr if (depth == 32 || (bounds.width() < lower_bound && bounds.height() < lower_bound)) return true; - QBezier first_half, second_half; - bezier.split(&first_half, &second_half); - if (qt_isect_curve_vertical(first_half, x, y1, y2, depth + 1) - || qt_isect_curve_vertical(second_half, x, y1, y2, depth + 1)) + const auto halves = bezier.split(); + if (qt_isect_curve_vertical(halves.first, x, y1, y2, depth + 1) + || qt_isect_curve_vertical(halves.second, x, y1, y2, depth + 1)) return true; } return false; -- cgit v1.2.3