2.5 KiB
2.5 KiB
WheelStep
- 功能描述： 指定数字输入框上鼠标轮上下滚动产生的变化值
- 使用位置： UPROPERTY
- 引擎模块： Numeric Property
- 元数据类型： float/int
- 常用程度： ★★★
指定数字输入框上鼠标轮上下滚动产生的变化值。
默认值的规则：
如果属性是浮点数且UI滚动条范围小于10，则WheelStep=0.1，否则为1
如果属性是整数，则WheelStep=1
测试代码：
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = WheelStepTest)
float MyFloat_DefaultWheelStep = 50;
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = WheelStepTest, meta = (UIMin = "0", UIMax = "10"))
float MyFloat_SmallWheelStep = 1;
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = WheelStepTest, meta = (WheelStep = 10))
float MyFloat_HasWheelStep = 50;
效果图：
默认值不指定UIMin，UIMax也可以鼠标轮滚动变化值。默认为1
MyFloat_SmallWheelStep的UI范围只有10，则默认改变幅度0.1
指定WheelStep =10，则一下子变化10
原理：
通过代码可知，如果设置了WheelStep则用该值。
否则如果是浮点数且UI滚动条范围小于10，则WheelStep=0.1，否则为1
否则如果是整数，则WheelStep=1
virtual FReply SSpinBox<NumericType>::OnMouseWheel(const FGeometry& MyGeometry, const FPointerEvent& MouseEvent) override
{
if (bEnableWheel && PointerDraggingSliderIndex == INDEX_NONE && HasKeyboardFocus())
{
// If there is no WheelStep defined, we use 1.0 (Or 0.1 if slider range is <= 10)
constexpr bool bIsIntegral = TIsIntegral<NumericType>::Value;
const bool bIsSmallStep = !bIsIntegral && (GetMaxSliderValue() - GetMinSliderValue()) <= 10.0;
double Step = WheelStep.IsSet() && WheelStep.Get().IsSet() ? WheelStep.Get().GetValue() : (bIsSmallStep ? 0.1 : 1.0);
if (MouseEvent.IsControlDown())
{
// If no value is set for WheelSmallStep, we use the DefaultStep multiplied by the CtrlMultiplier
Step *= CtrlMultiplier.Get();
}
else if (MouseEvent.IsShiftDown())
{
// If no value is set for WheelBigStep, we use the DefaultStep multiplied by the ShiftMultiplier
Step *= ShiftMultiplier.Get();
}
const double Sign = (MouseEvent.GetWheelDelta() > 0) ? 1.0 : -1.0;
const double NewValue = InternalValue + (Sign * Step);
const NumericType RoundedNewValue = RoundIfIntegerValue(NewValue);
return FReply::Handled();
}
return FReply::Unhandled();
}