More of a general question towards the wine devs: According to gcc we have a lot of such float comparisons in the code. Isn't that a potential general problem?
Regards, Fabian Maurer
On Freitag, 4. Februar 2022 16:58:48 CET Robert Feuerbach wrote:
The float equality and flatness calculation in flatten_bezier can fail due to the limited precision of the float math. The equality test was replaced with a simple check against the given flatness tolerance.
Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=52492 Signed-off-by: Robert Feuerbach rjfeuerbach@gmail.com
dlls/gdiplus/graphicspath.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/dlls/gdiplus/graphicspath.c b/dlls/gdiplus/graphicspath.c index ce2666eedab..c1bdf226e52 100644 --- a/dlls/gdiplus/graphicspath.c +++ b/dlls/gdiplus/graphicspath.c @@ -109,7 +109,7 @@ static INT path_list_count(path_list_node_t *node)
- (x2, y2): first control point;
- (x3, y3): second control point;
- end : pointer to end point node
- flatness: admissible error of linear approximation.
- flatness: admissible error of linear approximation in coordinate
units. *
- Return value:
- TRUE : success
@@ -142,12 +142,13 @@ static BOOL flatten_bezier(path_list_node_t *start, REAL x2, REAL y2, REAL x3, R mp[2].X = (mp[1].X + mp[3].X) / 2.0; mp[2].Y = (mp[1].Y + mp[3].Y) / 2.0;
- if ((x2 == mp[0].X && y2 == mp[0].Y && x3 == mp[1].X && y3 == mp[1].Y)
|| - (x2 == mp[3].X && y2 == mp[3].Y && x3 == mp[4].X && y3 == mp[4].Y)) - return TRUE;
- pt = end->pt; pt_st = start->pt;
- /* test for closely spaced points to avoid limited-precision errors in
flatness check */ + if((fabs(pt.X - mp[2].X) + fabs(pt.Y - mp[2].Y) +
fabs(pt_st.X - mp[2].X) + fabs(pt_st.Y - mp[2].Y) ) <= flatness)return TRUE;- /* check flatness as a half of distance between middle point and a
linearized path */ if(fabs(((pt.Y - pt_st.Y)*mp[2].X + (pt_st.X - pt.X)*mp[2].Y + (pt_st.Y*pt.X - pt_st.X*pt.Y))) <=