RGB QColor(QRgb)

[weixj2003ld]

I want to create a QColor,I find that QColorcan be created by

QColor(int r,int g,int b,int a=255)

QColor(int r,int g,int b,int a=255)

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or by

QColor(QRgb color)

QColor(QRgb color)

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,Now I have two questions:
1.if the value of r,g,b is between 0 and 1,how to convert to int? because

QColor(int r,int g,int b,int a=255)

QColor(int r,int g,int b,int a=255)

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need int parameter?
2.If I use

QColor(QRgb color)

QColor(QRgb color)

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to create a color,how to convert (0,1) to tpye QRgb?
Thk u.