77 lines
2.5 KiB
Markdown
77 lines
2.5 KiB
Markdown
|
# 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：
|
|||
|
|
|
|||
|
|
```cpp
|
|||
|
|
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
|
|||
|
|
|
|||
|
|
```cpp
|
|||
|
|
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();
|
|||
|
|
}
|
|||
|
|
```
|