diff options
Diffstat (limited to 'src/gui')
-rw-r--r-- | src/gui/kernel/qscreen.cpp | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/src/gui/kernel/qscreen.cpp b/src/gui/kernel/qscreen.cpp index 8c25bea285..7d83cebd2b 100644 --- a/src/gui/kernel/qscreen.cpp +++ b/src/gui/kernel/qscreen.cpp @@ -335,6 +335,20 @@ Qt::ScreenOrientation QScreen::currentOrientation() const return d->platformScreen->currentOrientation(); } +// i must be power of two +static int log2(uint i) +{ + if (i == 0) + return -1; + + int result = 0; + while (!(i & 1)) { + ++result; + i >>= 1; + } + return result; +} + /*! Convenience function to compute the angle of rotation to get from rotation \a a to rotation \a b. @@ -346,7 +360,10 @@ int QScreen::angleBetween(Qt::ScreenOrientation a, Qt::ScreenOrientation b) if (a == Qt::UnknownOrientation || b == Qt::UnknownOrientation || a == b) return 0; - int delta = int(b) - int(a); + int ia = log2(uint(a)); + int ib = log2(uint(b)); + + int delta = ia - ib; if (delta < 0) delta = delta + 4; |