Add QStyle::SH_SpinBox_StepModifier style hint

This patch allows the developer to pick which keyboard modifier
increases the number of steps a QAbstractSpinBox takes when the user
interacts with it.

The modifier can be either Qt::ControlModifier (default),
Qt::ShiftModifier or Qt::NoModifier. Qt::NoModifier disables the step
modifier. Note that on macOS, Control corresponds to the Command key.

Holding the modifier increases the step rate when:
- scrolling;
- pressing the up/down keys;
- pressing the spin box up/down buttons.

[ChangeLog][QtWidgets][QStyle] QStyle::SH_SpinBox_StepModifier allows
the developer to pick which keyboard modifier increases the number of
steps a QAbstractSpinBox takes for the following interactions:
scrolling, up/down keyboard keys and the spin box buttons. The
Qt::ShiftModifier can now be used, or the feature can be disabled
using Qt::NoModifier. Previously, only Qt::ControlModifier could be
used as the modifier.

Change-Id: Ib5518127e86a8f67798a9a1d6e860c6e35896e6f
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/widgets/styles/qstyle.h b/src/widgets/styles/qstyle.h
index cef569d514..9192dae864 100644
--- a/src/widgets/styles/qstyle.h
+++ b/src/widgets/styles/qstyle.h
@@ -741,6 +741,7 @@ public:
         SH_Widget_Animation_Duration,
         SH_ComboBox_AllowWheelScrolling,
         SH_SpinBox_ButtonsInsideFrame,
+        SH_SpinBox_StepModifier,
         // Add new style hint values here
 
         SH_CustomBase = 0xf0000000