Ensures GDI+ is present and running, or shuts it down. Needed only when writing FLI graphics code on Windows.
A function, or
ensure-gdiplus checks that the GDI+ module
gdiplus.dll is loaded and that
GdiplusStartup has been called, or shuts down GDI+.
Most users will not need to call
ensure-gdiplus. This is because when LispWorks itself uses GDI+, for instance via read-external-image, it calls
ensure-gdiplus automatically, and never shuts GDI+ down.
However, if your code uses GDI+ directly (by calling it through the Foreign Language Interface), then you should call
ensure-gdiplus instead of using
GdiplusStartup directly. Then, LispWorks will know that GDI+ has already started. This is the only circumstance in which you need to call
ensure-gdiplus is implemented only in LispWorks for Windows.
ensure-gdiplus ensures GDI+ is started, by the following steps:
Load the GDI+ module
gdiplus.dll, if it is not already loaded.
a) GDI+ was already started by a previous call to
was either not passed or is
cl:eq to the value that was passed for point a)
ensure-gdiplus simply returns
If GDI+ was already started, shut it down.
Start GDI+, and return the result of
GdiplusStartup. This is 0 for success. For he meaning of other values, see the documentation of
gpStatus in the MSDN.
is true, then if GDI+ was started
ensure-gdiplus shuts it down, and returns
nil. The default value of
The default value of both
CAPI User Guide and Reference Manual (Windows version) - 3 Aug 2017