将Obj()函数转换为Swift。min = MIN( r，MIN(g，b ))；等
将Obj()函数转换为Swift。min = MIN( r，MIN(g，b ))；等
提问于 2015-04-22 20:02:41
有谁能帮我做这件事吗？这个功能是在一个相机应用程序中，它使用过滤算法来检测颜色变化等方面的差异。语法对我来说非常困难。我不知道如何处理参数中的指针、min和max变量语法、什么是增量等等？有人能帮我翻译一下吗？非常感谢。
我还应该用UIColor做点什么吗？下面有人提过了。不过，我不知道该如何转换。
// r,g,b values are from 0 to 1 // h = [0,360], s = [0,1], v = [0,1]
// if s == 0, then h = -1 (undefined)
void RGBtoHSV( float r, float g, float b, float *h, float *s, float *v ) {
float min, max, delta;
min = MIN( r, MIN(g, b ));
max = MAX( r, MAX(g, b ));
*v = max;
delta = max - min;
if( max != 0 )
*s = delta / max;
else {
// r = g = b = 0
*s = 0;
*h = -1;
return;
}
if( r == max )
*h = ( g - b ) / delta;
else if( g == max )
*h=2+(b-r)/delta;
else
*h=4+(r-g)/delta;
*h *= 60;
if( *h < 0 )
*h += 360;
}快速翻译尝试
// r,g,b values are from 0 to 1 // h = [0,360], s = [0,1], v = [0,1]
// if s == 0, then h = -1 (undefined)
func RGBtoHSV(r:Float, g:Float, b:Float, h:Float, s:Float, v:Float) {
var min:Float = 0.0
var max:Float = 0.0
var delta:Float = 0.0
min = MIN(r, MIN(g, b))
max = MAX(r, MAX(g, b))
var v = max
delta = max - min
if max != 0 {
var s = delta / max
}
else{
// r = g = b = 0
var s = 0
var h = -1
return
}
if r == max {
var h = (g - b) / delta
}
else if (g == max) {
var h = 2 + (b - r ) / delta
}
else{
var h = 4 + (r - g) / delta
var h = 60
}
if (h < 0) {
var h += 360 // how to deal with all of these pointers here in the original Obj-C function above?
}
}回答 1
Stack Overflow用户
回答已采纳
发布于 2015-04-22 21:10:30
传递指针(变量地址)的Swift等效值是"inout参数“：
func RGBtoHSV(r : Float, g : Float, b : Float, inout h : Float, inout s : Float, inout v : Float) {
let rgbMin = min(r, g, b)
let rgbMax = max(r, g, b)
let delta = rgbMax - rgbMin
v = rgbMax
s = delta/rgbMax
h = Float(0.0) // Replace by your actual calculation
}这将被称为
let r : Float = 0.3
let g : Float = 0.5
let b : Float = 0.7
var h : Float = 0.0
var s : Float = 0.0
var v : Float = 0.0
RGBtoHSV(r, g, b, &h, &s, &v)
println([h, s, v])但是在Swift中有一种更好的方法来返回多个值:您可以返回一个元组
func RGBtoHSV(r : Float, g : Float, b : Float) -> (h : Float, s : Float, v : Float) {
let rgbMin = min(r, g, b)
let rgbMax = max(r, g, b)
let delta = rgbMax - rgbMin
let v = rgbMax
let s = delta/rgbMax
let h = Float(0.0) // Replace by your actual calculation
return (h, s, v)
}这将被称为
let r : Float = 0.3
let g : Float = 0.5
let b : Float = 0.7
let (h, s, v) = RGBtoHSV(r, g, b)
println([h, s, v])注意，在iOS上，您可以简单地使用UIColor类在RGB和HSV (== HSB)之间进行转换：
func RGBtoHSV(r : CGFloat, g : CGFloat, b : CGFloat) -> (h : CGFloat, s : CGFloat, v : CGFloat) {
var h : CGFloat = 0.0
var s : CGFloat = 0.0
var v : CGFloat = 0.0
let col = UIColor(red: r, green: g, blue: b, alpha: 1.0)
col.getHue(&h, saturation: &s, brightness: &v, alpha: nil)
return (h, s, v)
}(或使用来自What is the best/shortest way to convert a UIColor to hex (web color) in Swift?的各种扩展/方便方法)
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/29807686
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