| title | author | date | CreateTime | categories |
|---|---|---|---|---|
win10 uwp 颜色转换 |
lindexi |
2019-11-29 10:18:27 +0800 |
2018-2-13 17:23:3 +0800 |
Win10 UWP |
本文告诉大家如何从字符串转颜色，从颜色转字符串
字符串转颜色
在 WPF 可以使用下面的代码把十六进制的颜色字符串转颜色
Color color = (Color) ColorConverter.ConvertFromString("#FFDFD991");
string hex = "#FFFFFF";
Color color = System.Drawing.ColorTranslator.FromHtml(hex); 但是 UWP 没这个方法，所以需要自己写一个方法
public SolidColorBrush GetSolidColorBrush(string hex)
{
hex = hex.Replace("#", string.Empty);
byte a = (byte) (Convert.ToUInt32(hex.Substring(0, 2), 16));
byte r = (byte) (Convert.ToUInt32(hex.Substring(2, 2), 16));
byte g = (byte) (Convert.ToUInt32(hex.Substring(4, 2), 16));
byte b = (byte) (Convert.ToUInt32(hex.Substring(6, 2), 16));
return new SolidColorBrush(Windows.UI.Color.FromArgb(a, r, g, b));
}如果有小伙伴传入一个不带透明的，那么上面的代码就会出现异常，因为不带透明的颜色只有 6 个字符，所以就无法使用上面的代码，我修改了下面代码可以转换颜色
public SolidColorBrush GetSolidColorBrush(string hex)
{
hex = hex.Replace("#", string.Empty);
bool existAlpha = hex.Length == 8;
if (!existAlpha && hex.Length != 6)
{
throw new ArgumentException("输入的hex不是有效颜色");
}
int n = 0;
byte a;
if (existAlpha)
{
n = 2;
a = (byte) ConvertHexToByte(hex, 0);
}
else
{
a = 0xFF;
}
var r = (byte) ConvertHexToByte(hex, n);
var g = (byte) ConvertHexToByte(hex, n + 2);
var b = (byte) ConvertHexToByte(hex, n + 4);
return new SolidColorBrush(Windows.UI.Color.FromArgb(a, r, g, b));
}
private static uint ConvertHexToByte(string hex, int n)
{
return Convert.ToUInt32(hex.Substring(n, 2), 16);
}大家可以从上面代码发现 ConvertHexToByte 这就是 16 进制转 int 的方法，请看C# 16 进制字符串转 int
但是存在这样写的颜色 #FD92 #DAC 的颜色，所以还需要继续修改一下算法
public SolidColorBrush GetSolidColorBrush(string hex)
{
hex = hex.Replace("#", string.Empty);
//#FFDFD991
//#DFD991
//#FD92
//#DAC
bool existAlpha = hex.Length == 8 || hex.Length == 4;
bool isDoubleHex = hex.Length == 8 || hex.Length == 6;
if (!existAlpha && hex.Length != 6 && hex.Length != 3)
{
throw new ArgumentException("输入的hex不是有效颜色");
}
int n = 0;
byte a;
int hexCount = isDoubleHex ? 2 : 1;
if (existAlpha)
{
n = hexCount;
a = (byte) ConvertHexToByte(hex, 0, hexCount);
if (!isDoubleHex)
{
a = (byte) (a * 16 + a);
}
}
else
{
a = 0xFF;
}
var r = (byte) ConvertHexToByte(hex, n, hexCount);
var g = (byte) ConvertHexToByte(hex, n + hexCount, hexCount);
var b = (byte) ConvertHexToByte(hex, n + 2 * hexCount, hexCount);
if (!isDoubleHex)
{
//#FD92 = #FFDD9922
r = (byte) (r * 16 + r);
g = (byte) (g * 16 + g);
b = (byte) (b * 16 + b);
}
return new SolidColorBrush(Windows.UI.Color.FromArgb(a, r, g, b));
}
private static uint ConvertHexToByte(string hex, int n, int count = 2)
{
return Convert.ToUInt32(hex.Substring(n, count), 16);
}如果想看微软的转换，请看 https://referencesource.microsoft.com/#PresentationCore/Core/CSharp/System/Windows/Media/Parsers.cs
可以复制的源代码：
<script src="https://gist.github.com/lindexi/36c5e223ff77cfb8adc4909dec1576b5.js"></script>如果你没有在上面看到代码，请点击 <https://gist.github.com/lindexi/36c5e223ff77cfb8adc4909dec1576b5 >
颜色转字符串
如果需要从颜色转字符串是很简单
Color.ToString()上面的代码就可以输出字符串