sos!帮帮忙，改一下代码！

[freshstudent]

......
procedure Tform1.hsvtorgb(Hue:Thue;saturation,value:byte;var red,green,blue:byte);
var
f,h,m,n:Double;
a:integer;
w,y,z:byte;
begin
m:=saturation/255;
if m=0 then //出错显示“left side cannot be assigned to”
red:=green:=blue:=value
else
begin
h:=hue/60;
a:=hue div 60;
f:=h-a;
w:=value*(byte)(1-m);//出错显示’incompatibletype：‘byte’and‘extendede’下来两句同样的错误
y:=value*(1-m*f);
z:=value*(1-m*(1-f));
case a of
0: red:=value,green:=k,blue:=m;
1: red:=y,green:=value,blue:=m;
2: red:=w,green:=value,blue:=k;
3: red:=w,green:=n,blue:=value;
4: red:=z,green:=m,blue:=value;
5: red:=value,green:=m,blue:=n;
end;
end;
......

[CloneCenter]

red:=green:=blue:=value
Pascal 中不能这样写。得一个一个来。
begin
red := value;
green := value;
blue := value
end

[freshstudent]

我已经知道这个错了，但那个类型转换呢？请再指点指点！