来自UIImage的偏振滤波器 [英] polaroid filter from UIImage
本文介绍了来自UIImage的偏振滤波器的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
double minRGB（double r，double g ，双b）{
if（r
} else {
return b;
} else {
if（g
} else {
return b;
$ b double maxRGB（double r，double g，double b）{
if（ r> g）{
if（r> b）{
return r;
} else {
return b;
} else {
if（g> b）{
return g;
} else {
return b;
$ b void rgbToHsv（double redIn，double greenIn，double blueIn，double * hue，double * saturation，double * value）{
double min，max，delta;
min = minRGB（redIn，greenIn，blueIn）;
max = maxRGB（redIn，greenIn，blueIn）;
* value = max;
delta = max - min;
if（max！= 0）{
* saturation = delta / max;
} else {
* saturation = 0;
* hue = -1.0;
return;
if（redIn == max）{
* hue =（greenIn - blueIn）/ delta;
} else if（greenIn == max）{
* hue = 2 +（blueIn - redIn）/ delta;
} else {
* hue = 4 +（redIn - greenIn）/ delta;
}
* hue * = 60.0;
if（* hue <0）{
* hue + = 360.0;
void hsvToRgb（double h，double s，double v，double * r，double * g，double * b）{
int i;
float f，p，q，t;
if（s == 0）{
// achromatic（gray）
* r = * g = * b = v;
return;
}
h / = 60; //扇区0到5
i = floor（h）;
f = h - i; // h
p = v *（1 - s）的阶乘部分;
q = v *（1-s * f）;
t = v *（1-s *（1-f））;
switch（i）{
case 0：
* r = v;
* g = t;
* b = p;
break;
案例1：
* r = q;
* g = v;
* b = p;
break;
案例2：
* r = p;
* g = v;
* b = t;
break;
案例3：
* r = p;
* g = q;
* b = v;
break;
案例4：
* r = t;
* g = p;
* b = v;
break;
default：// case 5：
* r = v;
* g = p;
* b = q;
break;
- （void）makeImagePolaroid：（UIImage *）myImage {
CGImageRef originalImage = [myImage CGImage];
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB（）; （CGImageGetHeight（originalImage），8，CGImageGetWidth（originalImage）* 4，colorSpace，kCGImageAlphaPremultipliedLast）;
CGColorSpaceRelease（colorSpace）;
CGContextDrawImage（bitmapContext，CGRectMake（0，0，CGBitmapContextGetWidth（bitmapContext），CGBitmapContextGetHeight（bitmapContext）），originalImage）;
UInt8 * data = CGBitmapContextGetData（bitmapContext）;
int numComponents = 4;
int bytesInContext = CGBitmapContextGetHeight（bitmapContext）* CGBitmapContextGetBytesPerRow（bitmapContext）;
double redIn，greenIn，blueIn，alphaIn;
双色调，饱和度，价值; （int i = 0; i< bytesInContext; i + = numComponents）{
redIn =（double）data [i] /255.0;
greenIn =（double）data [i + 1] /255.0;
blueIn =（double）data [i + 2] /255.0;
alphaIn =（double）data [i + 3] /255.0;
rgbToHsv（redIn，greenIn，blueIn，& hue，& saturation，& value）;
hue = hue * 0.7;
if（hue> 360）{
hue = 360;
}
饱和度=饱和度* 1.3;
if（饱和度> 1.0）{
saturation = 1.0;
}
value = value * 0.8;
if（value> 1.0）{
value = 1.0;
}
hsvToRgb（hue，saturation，value，& redIn，& greenIn，& blueIn）;
data [i] = redIn * 255.0;
data [i + 1] = greenIn * 255.0;
data [i + 2] = blueIn * 255.0;
}
CGImageRef outImage = CGBitmapContextCreateImage（bitmapContext）;
myImage = [UIImage imageWithCGImage：outImage];
CGImageRelease（outImage）;
返回myImage;
$ b现在我对图像处理的想法是非常幼稚的（甚至不是业余的）。我阅读了这个并试图调整饱和度和色调，看看我是否可以得到一个宝丽来效果..我想我失去了一些东西，因为我得到了除了宝丽来以外的地球上的每一个效果（说我没有得到任何东西）..
- 在
视图的程序员点上是否有任何有关net（或
books）的文档，它告诉我们有关image
的过滤功能？ （而不是一个设计师点
的视图和没有一个Photoshop
截图）
- 什么是色相，饱和度，价值
差异我必须使像素
，使我可以使宝丽来？
- 第三，我在正确的轨道上吗？
在此先感谢..
解决方案 photoshop和再现他们的iOS。
http://taptaptap.com/blog/creating-a-camera-plus-fx/
I am trying to implement some image filters, like polaroid, in iphone. I searched on how to filter an existing UIImage to convert it into a polaroid style and come across this stackoverflow link. Taking the answer there as a starting point, I looped through each pixel of the image, taking RGB values, and converted them to HSV, up to this point I have been successful. So this is what I have done (anyone is free to point any mistakes..)
double minRGB(double r, double g, double b){
if (r < g){
if (r < b){
return r;
}else {
return b;
}
}else {
if (g < b){
return g;
}else{
return b;
}
}
}
double maxRGB(double r, double g, double b){
if (r > g){
if (r > b){
return r;
}else {
return b;
}
}else {
if (g > b){
return g;
}else {
return b;
}
}
}
void rgbToHsv(double redIn,double greenIn,double blueIn,double *hue,double *saturation,double* value){
double min,max,delta;
min = minRGB(redIn,greenIn,blueIn);
max = maxRGB(redIn,greenIn,blueIn);
*value = max;
delta = max - min;
if (max != 0) {
*saturation = delta/max;
}else {
*saturation = 0;
*hue = -1.0;
return ;
}
if (redIn == max) {
*hue = (greenIn - blueIn)/delta;
}else if (greenIn == max) {
*hue = 2 + (blueIn - redIn)/delta;
}else {
*hue = 4 + (redIn - greenIn)/delta;
}
*hue *= 60.0;
if (*hue < 0) {
*hue += 360.0;
}
}
void hsvToRgb(double h,double s, double v, double *r,double *g, double *b){
int i;
float f, p, q, t;
if( s == 0 ) {
// achromatic (grey)
*r = *g = *b = v;
return;
}
h /= 60; // sector 0 to 5
i = floor( h );
f = h - i; // factorial part of h
p = v * ( 1 - s );
q = v * ( 1 - s * f );
t = v * ( 1 - s * ( 1 - f ) );
switch( i ) {
case 0:
*r = v;
*g = t;
*b = p;
break;
case 1:
*r = q;
*g = v;
*b = p;
break;
case 2:
*r = p;
*g = v;
*b = t;
break;
case 3:
*r = p;
*g = q;
*b = v;
break;
case 4:
*r = t;
*g = p;
*b = v;
break;
default: // case 5:
*r = v;
*g = p;
*b = q;
break;
}
}
-(void)makeImagePolaroid:(UIImage*)myImage{
CGImageRef originalImage = [myImage CGImage];
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef bitmapContext = CGBitmapContextCreate(NULL,CGImageGetWidth(originalImage),CGImageGetHeight(originalImage),8,CGImageGetWidth(originalImage)*4,colorSpace,kCGImageAlphaPremultipliedLast);
CGColorSpaceRelease(colorSpace);
CGContextDrawImage(bitmapContext, CGRectMake(0, 0, CGBitmapContextGetWidth(bitmapContext), CGBitmapContextGetHeight(bitmapContext)), originalImage);
UInt8 *data = CGBitmapContextGetData(bitmapContext);
int numComponents = 4;
int bytesInContext = CGBitmapContextGetHeight(bitmapContext) * CGBitmapContextGetBytesPerRow(bitmapContext);
double redIn, greenIn, blueIn,alphaIn;
double hue,saturation,value;
for (int i = 0; i < bytesInContext; i += numComponents) {
redIn = (double)data[i]/255.0;
greenIn = (double)data[i+1]/255.0;
blueIn = (double)data[i+2]/255.0;
alphaIn = (double)data[i+3]/255.0;
rgbToHsv(redIn,greenIn,blueIn,&hue,&saturation,&value);
hue = hue * 0.7;
if (hue > 360) {
hue = 360;
}
saturation = saturation *1.3;
if (saturation > 1.0) {
saturation = 1.0;
}
value = value * 0.8;
if (value > 1.0) {
value = 1.0;
}
hsvToRgb(hue,saturation,value,&redIn,&greenIn,&blueIn);
data[i] = redIn * 255.0;
data[i+1] = greenIn * 255.0;
data[i+2] = blueIn * 255.0;
}
CGImageRef outImage = CGBitmapContextCreateImage(bitmapContext);
myImage = [UIImage imageWithCGImage:outImage];
CGImageRelease(outImage);
return myImage;
}
Now my idea about image processing is very childish (not even amateurish). I read this and tried to adjust the saturation and hue to see if I can get a polaroid effect..I think I am missing something, for I got every effect on earth other than a polaroid (saying that I havent got anything)..
- Is there any document on net (or
books) which tells about image
filtering on a programmers point of
view? (and not on a designers point
of view and without a photoshop
screenshot)
- What is the hue, saturation, value
difference I have to make on a pixel
so that I can make it polaroid?
- And third, Am I on the right track?
Thanks in advance..
解决方案 This might be helpful, from Camera+ taking filters from photoshop and reproducing them for iOS.
http://taptaptap.com/blog/creating-a-camera-plus-fx/
这篇关于来自UIImage的偏振滤波器的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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