eb76f400d2
If wxTextMeasure is constructed without a font and the base version of DoGetPartialTextExtents() gets used then there's a crash due to dereferencing a null pointer. To fix, simply use GetFont() like elsewhere to get the effective font used. To fix another null pointer dereference crash don't call wxTextMeasure::DoGetTextExtent() with null height pointer, as it requires that both width and height pointers are non-null since8cd79b7af0(Factor out text measurement from wxDC and wxWindow into wxTextMeasure., 2012-10-18), but not for all back-ends any longer sinced76774b444(Don't dereference NULL output pointer in wxTextMeasure., 2012-11-25). There currently appears to be no code in wx that would result in either crash. For Windows both crashes can be artificially reproduced with the render sample (requiring static linking with wx due to using private wxTextMeasure) when using the GDI+ renderer along with the patch: diff --git a/samples/render/render.cpp b/samples/render/render.cpp index 6bae34781b..bc4f8d405b 100644 --- a/samples/render/render.cpp +++ b/samples/render/render.cpp @@ -34,6 +34,7 @@ #include "wx/image.h" #endif +#include "wx/private/textmeasure.h" #include "wx/apptrait.h" #include "wx/artprov.h" #include "wx/renderer.h" @@ -209,6 +210,10 @@ private: wxGraphicsContext* ctx = m_renderer->CreateContext(pdc); gdc.SetBackground(GetBackgroundColour()); gdc.SetGraphicsContext(ctx); + + wxTextMeasure txm(&gdc); + wxArrayInt widths; + txm.GetPartialTextExtents("a", widths, 1.0); } wxDC& dc = m_renderer ? static_cast<wxDC&>(gdc) : pdc; Closes https://github.com/wxWidgets/wxWidgets/pull/2471
About
wxWidgets is a free and open source cross-platform C++ framework for writing advanced GUI applications using native controls.
wxWidgets allows you to write native-looking GUI applications for all the major desktop platforms and also helps with abstracting the differences in the non-GUI aspects between them. It is free for the use in both open source and commercial applications, comes with the full, easy to read and modify, source and extensive documentation and a collection of more than a hundred examples. You can learn more about wxWidgets at https://www.wxwidgets.org/ and read its documentation online at https://docs.wxwidgets.org/
Platforms
This version of wxWidgets supports the following primary platforms:
- Windows XP, Vista, 7, 8 and 10 (32/64 bits).
- Most Unix variants using the GTK+ toolkit (version 2.6 or newer or 3.x).
- macOS (10.10 or newer) using Cocoa under both amd64 and ARM platforms.
Most popular C++ compilers are supported including but not limited to:
- Microsoft Visual C++ 2005 or later (up to 2019).
- g++ 4 or later, including MinGW/MinGW-64/TDM under Windows.
- Clang under macOS and Linux.
- Intel icc compiler.
- Oracle (ex-Sun) CC.
Licence
wxWidgets licence is a modified version of LGPL explicitly allowing not distributing the sources of an application using the library even in the case of static linking.
Building
For building the library, please see platform-specific documentation under
docs/<port> directory, e.g. here are the instructions for
wxGTK, wxMSW and
wxOSX.
If you're building the sources checked out from Git, and not from a released version, please see these additional Git-specific notes.
Further information
If you are looking for community support, you can get it from
- Mailing Lists
- Discussion Forums
- #wxwidgets IRC channel
- Stack Overflow
(tag your questions with
wxwidgets) - And you can report bugs at https://trac.wxwidgets.org/newticket
Commercial support is also available.
Finally, keep in mind that wxWidgets is an open source project collaboratively developed by its users and your contributions to it are always welcome. Please check our guidelines if you'd like to do it.
Have fun!
The wxWidgets Team.