Hi Regina,
yes, the MiterLimits are different in different systems, but all are
somehow specified using the angle between the two vectors involved. I
remember to have seen some definitions, most using the same and 15 as
default value. The ways to be compatible with MS are:
- find a definition somewhere, mqaybe in forums or newsgroups (I have
none, sorry)
- reverse engineer by trying out. Probability is high that there is a
(linear?) relationship between the values, so it might be a simple scaling
HTH!
Regards,
Armin
Am 07.04.2016 um 14:35 schrieb Regina Henschel:
Hi all,
I have made some progress. But a new problem comes up.
I have changed WinSalGraphicsImpl::drawPolyLine [3] so that it gets an
additional parameter fMiterMinimumAngle (same meaning as in
createAreaGeometryForJoin) and uses it for gdi+. The rendering in
edit-mode in Draw and Impress is correct then with gdi+ on Windows.
Even Text in SVG works out of the box. [BTW: The current rendering
using gdi+ is wrong, see my report bug#99102.]
The behavior of gdi+ is described in [1]. To get the same kind of
behavior as in LO, when the miter limit is exceeded, the LineJoin type
'LineJoinMiterClipped' has to be used.
Being only in LibreOffice and SVG, that would be no problem. But MS
seems to use different defaults. The rendering in PowerPoint looks
like gdi+ type 'LineJoinMiter'. The specification for 'lim' in
ECMA-376, Part 1, chapter 20.1.8.43, has no details, and I have not
found details otherwhere.
This gdi+ type 'LineJoinMiter' kind of clipping (see the image in the
article [1]) will be used in SVG 2 [2] too under the identifier
'miter-clip'.
So my question: Ignore interoperability with MS? If not, how to solve it?
Kind regards
Regina
[1]
https://msdn.microsoft.com/en-us/library/windows/desktop/ms534148%28v=vs.85%29.aspx
[2] https://www.w3.org/TR/svg-strokes/#StrokeShape
[3]
diff --git a/vcl/win/gdi/gdiimpl.cxx b/vcl/win/gdi/gdiimpl.cxx
index 7febbe8..36ecb31 100644
--- a/vcl/win/gdi/gdiimpl.cxx
+++ b/vcl/win/gdi/gdiimpl.cxx
@@ -2031,7 +2031,8 @@ bool WinSalGraphicsImpl::drawPolyLine(
double fTransparency,
const basegfx::B2DVector& rLineWidths,
basegfx::B2DLineJoin eLineJoin,
- css::drawing::LineCap eLineCap)
+ css::drawing::LineCap eLineCap,
+ double fMiterMinimumAngle)
{
const sal_uInt32 nCount(rPolygon.count());
@@ -2064,9 +2065,9 @@ bool WinSalGraphicsImpl::drawPolyLine(
}
case basegfx::B2DLineJoin::Miter :
{
- const Gdiplus::REAL aMiterLimit(15.0);
+ const Gdiplus::REAL
aMiterLimit(1/sin(fMiterMinimumAngle/2.0));
Gdiplus::DllExports::GdipSetPenMiterLimit(pTestPen, aMiterLimit);
- Gdiplus::DllExports::GdipSetPenLineJoin(pTestPen,
Gdiplus::LineJoinMiter);
+ Gdiplus::DllExports::GdipSetPenLineJoin(pTestPen,
Gdiplus::LineJoinMiterClipped);
break;
}
case basegfx::B2DLineJoin::Round :
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