Fix regression in wxMSW wxDC::SetAxisOrientation().

Don't mix signed/unsigned integers in arithmetic operations when normalizing
wxDC scale factors: variable holding GCD value should be of the same type as
variables holding devExt and logExt to avoid wrong results of /= operation
when dividend is a negative value.

Closes #16908.

docs/changes.txt

@@ -601,6 +601,7 @@ wxGTK:
 
 wxMSW:
 
+- Fix regression in wxDC drawing with bottom-to-top y axis (Artur Wieczorek).
 - Fix compilation with C++Builder XE compiler (Nichka).
 - Fix best height of wxSlider with labels but without ticks (Artur Wieczorek).
 - Fix initial text value of wxSpinCtrlDouble (Laurent Poujoulat).

src/msw/dc.cpp

@@ -2007,7 +2007,7 @@ void wxMSWDCImpl::RealizeScaleAndOrigin()
     // Becaue only devExtX/logExtX ratio and devExtY/logExtY ratio are counted
     // we can reduce the fractions to avoid large absolute numbers
     // and possible arithmetic overflows.
-    unsigned int gcd = CalcGCD(abs(devExtX), abs(logExtX));
+    int gcd = CalcGCD(abs(devExtX), abs(logExtX));
     devExtX /= gcd;
     logExtX /= gcd;
     gcd = CalcGCD(abs(devExtY), abs(logExtY));