62 lines
2.4 KiB
Markdown
62 lines
2.4 KiB
Markdown
# LinearDeltaSensitivity
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- **功能描述：** 在设定Delta后，进一步设定数字输入框变成线性改变以及改变的敏感度（值越大越不敏感）
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- **使用位置：** UPROPERTY
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- **引擎模块：** Numeric Property
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- **元数据类型：** float/int
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- **限制类型：** float,int32
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- **关联项：** [Delta](Delta/Delta.md)
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- **常用程度：** ★★★
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生效的条件：
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1. 先设置Delta>0
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2. 不设置UIMin, UIMax
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3. 设定LinearDeltaSensitivity >0
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## 测试代码：
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```cpp
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UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = DeltaTest, meta = (UIMin = "0", UIMax = "1000", Delta = 10))
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float MyFloat_Delta10_UIMinMax = 100;
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UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = DeltaTest, meta = (Delta = 10, LinearDeltaSensitivity = 50))
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float MyFloat_Delta10_LinearDeltaSensitivity50 = 100;
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UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = DeltaTest, meta = (UIMin = "0", UIMax = "1000", Delta = 10, LinearDeltaSensitivity = 50))
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float MyFloat_Delta10_LinearDeltaSensitivity50_UIMinMax = 100;
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```
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## 测试效果：
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效果解析请参见：Delta的解析
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## 原理：
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可见只有没有UIMinMax且已经设置Delta后才能走进线性改变的代码分支。
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```cpp
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, _Delta(0)
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virtual FReply SSpinBox<NumericType>::OnMouseMove(const FGeometry& MyGeometry, const FPointerEvent& MouseEvent) override
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{
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if (bUnlimitedSpinRange)
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{
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// If this control has a specified delta and sensitivity then we use that instead of the current value for determining how much to change.
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const double Sign = (MouseEvent.GetCursorDelta().X > 0) ? 1.0 : -1.0;
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if (LinearDeltaSensitivity.IsSet() && LinearDeltaSensitivity.Get() != 0 && Delta.IsSet() && Delta.Get() > 0)
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{
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const double MouseDelta = FMath::Abs(MouseEvent.GetCursorDelta().X / (float)LinearDeltaSensitivity.Get());
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NewValue = InternalValue + (Sign * MouseDelta * FMath::Pow((double)Delta.Get(), (double)SliderExponent.Get())) * Step;
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}
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else
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{
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const double MouseDelta = FMath::Abs(MouseEvent.GetCursorDelta().X / SliderWidthInSlateUnits);
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const double CurrentValue = FMath::Clamp<double>(FMath::Abs(InternalValue), 1.0, (double)std::numeric_limits<NumericType>::max());
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NewValue = InternalValue + (Sign * MouseDelta * FMath::Pow((double)CurrentValue, (double)SliderExponent.Get())) * Step;
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}
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}
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}
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```
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