如何将 ARGB 值从字符串转换为颜色？

发布于 2024-08-30 01:30:48 字数 467 浏览 7 评论 0原文

我尝试在 GDIPAPI 单元中使用 MakeColor 方法，但从 int 到 byte 的转换没有返回正确的值。

示例

var
    argbStr: string;
    A, R, G, B: Byte;
begin
    argbStr := 'ffffcc88';
    A := StrToInt('$' + Copy(AValue, 1, 2));
    R := StrToInt('$' + Copy(AValue, 3, 2));
    G := StrToInt('$' + Copy(AValue, 5, 2));
    B := StrToInt('$' + Copy(AValue, 7, 2));
    Result := MakeColor(A, R, G, B);
end;

我做错了什么？

原文

I am trying to use the MakeColor method in the GDIPAPI unit but the conversion from int to byte is not returning me the correct value.

Example

var
    argbStr: string;
    A, R, G, B: Byte;
begin
    argbStr := 'ffffcc88';
    A := StrToInt('
What am I doing wrong?
 + Copy(AValue, 1, 2));
    R := StrToInt('
What am I doing wrong?
 + Copy(AValue, 3, 2));
    G := StrToInt('
What am I doing wrong?
 + Copy(AValue, 5, 2));
    B := StrToInt('
What am I doing wrong?
 + Copy(AValue, 7, 2));
    Result := MakeColor(A, R, G, B);
end;

What am I doing wrong?

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三人与歌 2024-09-06 01:30:48

字符串中颜色分量的顺序与 ARGB 值中的顺序相同。因此，在使用 MakeColor 组合组件之前，您不需要分离组件。您可以直接进行转换：

function StringToARGB(const argbStr: string): GDIPAPI.ARGB;
begin
  Result := ARGB(StrToInt('
类型转换对于抑制 alpha 分量大于 127 时出现的范围检查错误是必要的； StrToInt 返回有符号整数，但 ARGB 是无符号类型。
 + argbStr));
end;

类型转换对于抑制 alpha 分量大于 127 时出现的范围检查错误是必要的； StrToInt 返回有符号整数，但 ARGB 是无符号类型。

The color components in your string are in the same order they would have in a ARGB value. Therefore, you don't need to separate the components before combining them with MakeColor. You can do the conversion directly:

function StringToARGB(const argbStr: string): GDIPAPI.ARGB;
begin
  Result := ARGB(StrToInt('
The type-cast is necessary to suppress a range-checking error you'd get whenever the alpha component was greater than 127; StrToInt returns a signed integer, but ARGB is an unsigned type.
 + argbStr));
end;

The type-cast is necessary to suppress a range-checking error you'd get whenever the alpha component was greater than 127; StrToInt returns a signed integer, but ARGB is an unsigned type.

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