ios 滤镜
2016-08-12 12:24
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首先需要了解一下滤镜的原理：“用Core Graphic的API，把图片解析成RGBA四通道的位图放入内存，然后内存中有一个数组，数组中的每四个元素都是图像上的一个像素点的RGBA的数值(0-255)，你只要改变RGB的数值，再写回去重新生成就可以了。简单的变化RGB很好改的，变为黑白照片就是把每个像素点的RGB的值相加求平均值，再回写回去。例如：R=B=G=100，就是灰色的，你只要写个for循环，把每个像素点的RGB都改成各自的平均值，照片就变为黑白色了。如果图像变为怀旧照片，就是底色发黄的，就是RG的比值调高，B保持不变，因为红绿相配就是黄色。”
第一步打开位图的像素数组
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// 返回一个使用RGBA通道的位图上下文
static CGContextRef CreateRGBABitmapContext (CGImageRef inImage)
{
CGContextRef context = NULL;
CGColorSpaceRef colorSpace;
void *bitmapData; //内存空间的指针，该内存空间的大小等于图像使用RGB通道所占用的字节数。
int bitmapByteCount;
int bitmapBytesPerRow;
size_t pixelsWide = CGImageGetWidth(inImage); //获取横向的像素点的个数
size_t pixelsHigh = CGImageGetHeight(inImage);
bitmapBytesPerRow = (pixelsWide * 4); //每一行的像素点占用的字节数，每个像素点的ARGB四个通道各占8个bit(0-255)的空间
bitmapByteCount = (bitmapBytesPerRow * pixelsHigh); //计算整张图占用的字节数
colorSpace = CGColorSpaceCreateDeviceRGB();//创建依赖于设备的RGB通道
//分配足够容纳图片字节数的内存空间
bitmapData = malloc( bitmapByteCount );
//创建CoreGraphic的图形上下文，该上下文描述了bitmaData指向的内存空间需要绘制的图像的一些绘制参数
context = CGBitmapContextCreate (bitmapData,
pixelsWide,
pixelsHigh,
8,
bitmapBytesPerRow,
colorSpace,
kCGImageAlphaPremultipliedLast);
//Core Foundation中通过含有Create、Alloc的方法名字创建的指针，需要使用CFRelease()函数释放
CGColorSpaceRelease( colorSpace );
return context;
}
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// 返回一个指针，该指针指向一个数组，数组中的每四个元素都是图像上的一个像素点的RGBA的数值(0-255)，用无符号的char是因为它正好的取值范围就是0-255
static unsigned char *RequestImagePixelData(UIImage *inImage)
{
CGImageRef img = [inImage CGImage];
CGSize size = [inImage size];
//使用上面的函数创建上下文
CGContextRef cgctx = CreateRGBABitmapContext(img);
CGRect rect = {{0,0},{size.width, size.height}};
//将目标图像绘制到指定的上下文，实际为上下文内的bitmapData。
CGContextDrawImage(cgctx, rect, img);
unsigned char *data = CGBitmapContextGetData (cgctx);
//释放上面的函数创建的上下文
CGContextRelease(cgctx);
return data;
}
获得以像素为单位的长和宽，开始处理位图中每个像素的值，生成指定效果
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CGImageRef inImageRef = [inImage CGImage];
GLuint w = CGImageGetWidth(inImageRef);
GLuint h = CGImageGetHeight(inImageRef);
int wOff = 0;
int pixOff = 0;
//双层循环按照长宽的像素个数迭代每个像素点
for(GLuint y = 0;y< h;y++)
{
pixOff = wOff;
for (GLuint x = 0; x<w; x++)
{
int red = (unsigned char)imgPixel[pixOff];
int green = (unsigned char)imgPixel[pixOff+1];
int blue = (unsigned char)imgPixel[pixOff+2];
int alpha=(unsigned char)imgPixel[pixOff+3];
//NSLog(@"1------r=%d,g=%d,b=%d,a=%d,",red,green,blue,alpha);
changeRGBA(&red, &green, &blue, &alpha, f);
//NSLog(@"2------r=%d,g=%d,b=%d,a=%d,",red,green,blue,alpha);
//NSLog(@"--------------------------------------");
//回写数据
imgPixel[pixOff] = red;
imgPixel[pixOff+1] = green;
imgPixel[pixOff+2] = blue;
imgPixel[pixOff+3] = alpha;
//将数组的索引指向下四个元素
pixOff += 4;
}
wOff += w * 4;
}
NSInteger dataLength = w*h* 4;
创建生成image所需的参数
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//下面的代码创建要输出的图像的相关参数
CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, imgPixel, dataLength, NULL);
if (!provider) {
failedBlock(@"创建输出图像的相关参数失败！");
}else{
// prep the ingredients
int bitsPerComponent = 8;
int bitsPerPixel = 32;
int bytesPerRow = 4 * w;
CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();
CGBitmapInfo bitmapInfo = kCGBitmapByteOrderDefault;
CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;
//创建要输出的图像
CGImageRef imageRef = CGImageCreate(w, h,
bitsPerComponent,
bitsPerPixel,
bytesPerRow,
colorSpaceRef,
bitmapInfo,
provider,
NULL, NO, renderingIntent);
if (!imageRef) {
failedBlock(@"创建输出图像失败！");
}else{
UIImage *my_Image = [UIImage imageWithCGImage:imageRef];
CFRelease(imageRef);
CGColorSpaceRelease(colorSpaceRef);
CGDataProviderRelease(provider);
succeedBlock(my_Image);
}
下面附上几组原作者李海峰写的颜色矩阵的数值
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//ColorMatrix From Android
//lomo
const float colormatrix_lomo[] = {
1.7f, 0.1f, 0.1f, 0, -73.1f,
0, 1.7f, 0.1f, 0, -73.1f,
0, 0.1f, 1.6f, 0, -73.1f,
0, 0, 0, 1.0f, 0 };
//黑白
const float colormatrix_heibai[] = {
0.8f, 1.6f, 0.2f, 0, -163.9f,
0.8f, 1.6f, 0.2f, 0, -163.9f,
0.8f, 1.6f, 0.2f, 0, -163.9f,
0, 0, 0, 1.0f, 0 };
//旧化
const float colormatrix_huajiu[] = {
0.2f,0.5f, 0.1f, 0, 40.8f,
0.2f, 0.5f, 0.1f, 0, 40.8f,
0.2f,0.5f, 0.1f, 0, 40.8f,
0, 0, 0, 1, 0 };
//哥特
const float colormatrix_gete[] = {
1.9f,-0.3f, -0.2f, 0,-87.0f,
-0.2f, 1.7f, -0.1f, 0, -87.0f,
-0.1f,-0.6f, 2.0f, 0, -87.0f,
0, 0, 0, 1.0f, 0 };
//锐色
const float colormatrix_ruise[] = {
4.8f,-1.0f, -0.1f, 0,-388.4f,
-0.5f,4.4f, -0.1f, 0,-388.4f,
-0.5f,-1.0f, 5.2f, 0,-388.4f,
0, 0, 0, 1.0f, 0 };
//淡雅
const float colormatrix_danya[] = {
0.6f,0.3f, 0.1f, 0,73.3f,
0.2f,0.7f, 0.1f, 0,73.3f,
0.2f,0.3f, 0.4f, 0,73.3f,
0, 0, 0, 1.0f, 0 };
//酒红
const float colormatrix_jiuhong[] = {
1.2f,0.0f, 0.0f, 0.0f,0.0f,
0.0f,0.9f, 0.0f, 0.0f,0.0f,
0.0f,0.0f, 0.8f, 0.0f,0.0f,
0, 0, 0, 1.0f, 0 };
//清宁
const float colormatrix_qingning[] = {
0.9f, 0, 0, 0, 0,
0, 1.1f,0, 0, 0,
0, 0, 0.9f, 0, 0,
0, 0, 0, 1.0f, 0 };
//浪漫
const float colormatrix_langman[] = {
0.9f, 0, 0, 0, 63.0f,
0, 0.9f,0, 0, 63.0f,
0, 0, 0.9f, 0, 63.0f,
0, 0, 0, 1.0f, 0 };
//光晕
const float colormatrix_guangyun[] = {
0.9f, 0, 0, 0, 64.9f,
0, 0.9f,0, 0, 64.9f,
0, 0, 0.9f, 0, 64.9f,
0, 0, 0, 1.0f, 0 };
//蓝调
const float colormatrix_landiao[] = {
2.1f, -1.4f, 0.6f, 0.0f, -31.0f,
-0.3f, 2.0f, -0.3f, 0.0f, -31.0f,
-1.1f, -0.2f, 2.6f, 0.0f, -31.0f,
0.0f, 0.0f, 0.0f, 1.0f, 0.0f
};
//梦幻
const float colormatrix_menghuan[] = {
0.8f, 0.3f, 0.1f, 0.0f, 46.5f,
0.1f, 0.9f, 0.0f, 0.0f, 46.5f,
0.1f, 0.3f, 0.7f, 0.0f, 46.5f,
0.0f, 0.0f, 0.0f, 1.0f, 0.0f
};
//夜色
const float colormatrix_yese[] = {
1.0f, 0.0f, 0.0f, 0.0f, -66.6f,
0.0f, 1.1f, 0.0f, 0.0f, -66.6f,
0.0f, 0.0f, 1.0f, 0.0f, -66.6f,
0.0f, 0.0f, 0.0f, 1.0f, 0.0f
};
第一步打开位图的像素数组
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// 返回一个使用RGBA通道的位图上下文
static CGContextRef CreateRGBABitmapContext (CGImageRef inImage)
{
CGContextRef context = NULL;
CGColorSpaceRef colorSpace;
void *bitmapData; //内存空间的指针，该内存空间的大小等于图像使用RGB通道所占用的字节数。
int bitmapByteCount;
int bitmapBytesPerRow;
size_t pixelsWide = CGImageGetWidth(inImage); //获取横向的像素点的个数
size_t pixelsHigh = CGImageGetHeight(inImage);
bitmapBytesPerRow = (pixelsWide * 4); //每一行的像素点占用的字节数，每个像素点的ARGB四个通道各占8个bit(0-255)的空间
bitmapByteCount = (bitmapBytesPerRow * pixelsHigh); //计算整张图占用的字节数
colorSpace = CGColorSpaceCreateDeviceRGB();//创建依赖于设备的RGB通道
//分配足够容纳图片字节数的内存空间
bitmapData = malloc( bitmapByteCount );
//创建CoreGraphic的图形上下文，该上下文描述了bitmaData指向的内存空间需要绘制的图像的一些绘制参数
context = CGBitmapContextCreate (bitmapData,
pixelsWide,
pixelsHigh,
8,
bitmapBytesPerRow,
colorSpace,
kCGImageAlphaPremultipliedLast);
//Core Foundation中通过含有Create、Alloc的方法名字创建的指针，需要使用CFRelease()函数释放
CGColorSpaceRelease( colorSpace );
return context;
}
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// 返回一个指针，该指针指向一个数组，数组中的每四个元素都是图像上的一个像素点的RGBA的数值(0-255)，用无符号的char是因为它正好的取值范围就是0-255
static unsigned char *RequestImagePixelData(UIImage *inImage)
{
CGImageRef img = [inImage CGImage];
CGSize size = [inImage size];
//使用上面的函数创建上下文
CGContextRef cgctx = CreateRGBABitmapContext(img);
CGRect rect = {{0,0},{size.width, size.height}};
//将目标图像绘制到指定的上下文，实际为上下文内的bitmapData。
CGContextDrawImage(cgctx, rect, img);
unsigned char *data = CGBitmapContextGetData (cgctx);
//释放上面的函数创建的上下文
CGContextRelease(cgctx);
return data;
}
获得以像素为单位的长和宽，开始处理位图中每个像素的值，生成指定效果
[html] view
plain copy
CGImageRef inImageRef = [inImage CGImage];
GLuint w = CGImageGetWidth(inImageRef);
GLuint h = CGImageGetHeight(inImageRef);
int wOff = 0;
int pixOff = 0;
//双层循环按照长宽的像素个数迭代每个像素点
for(GLuint y = 0;y< h;y++)
{
pixOff = wOff;
for (GLuint x = 0; x<w; x++)
{
int red = (unsigned char)imgPixel[pixOff];
int green = (unsigned char)imgPixel[pixOff+1];
int blue = (unsigned char)imgPixel[pixOff+2];
int alpha=(unsigned char)imgPixel[pixOff+3];
//NSLog(@"1------r=%d,g=%d,b=%d,a=%d,",red,green,blue,alpha);
changeRGBA(&red, &green, &blue, &alpha, f);
//NSLog(@"2------r=%d,g=%d,b=%d,a=%d,",red,green,blue,alpha);
//NSLog(@"--------------------------------------");
//回写数据
imgPixel[pixOff] = red;
imgPixel[pixOff+1] = green;
imgPixel[pixOff+2] = blue;
imgPixel[pixOff+3] = alpha;
//将数组的索引指向下四个元素
pixOff += 4;
}
wOff += w * 4;
}
NSInteger dataLength = w*h* 4;
创建生成image所需的参数
[html] view
plain copy
//下面的代码创建要输出的图像的相关参数
CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, imgPixel, dataLength, NULL);
if (!provider) {
failedBlock(@"创建输出图像的相关参数失败！");
}else{
// prep the ingredients
int bitsPerComponent = 8;
int bitsPerPixel = 32;
int bytesPerRow = 4 * w;
CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();
CGBitmapInfo bitmapInfo = kCGBitmapByteOrderDefault;
CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;
//创建要输出的图像
CGImageRef imageRef = CGImageCreate(w, h,
bitsPerComponent,
bitsPerPixel,
bytesPerRow,
colorSpaceRef,
bitmapInfo,
provider,
NULL, NO, renderingIntent);
if (!imageRef) {
failedBlock(@"创建输出图像失败！");
}else{
UIImage *my_Image = [UIImage imageWithCGImage:imageRef];
CFRelease(imageRef);
CGColorSpaceRelease(colorSpaceRef);
CGDataProviderRelease(provider);
succeedBlock(my_Image);
}
下面附上几组原作者李海峰写的颜色矩阵的数值
[html] view
plain copy
//ColorMatrix From Android
//lomo
const float colormatrix_lomo[] = {
1.7f, 0.1f, 0.1f, 0, -73.1f,
0, 1.7f, 0.1f, 0, -73.1f,
0, 0.1f, 1.6f, 0, -73.1f,
0, 0, 0, 1.0f, 0 };
//黑白
const float colormatrix_heibai[] = {
0.8f, 1.6f, 0.2f, 0, -163.9f,
0.8f, 1.6f, 0.2f, 0, -163.9f,
0.8f, 1.6f, 0.2f, 0, -163.9f,
0, 0, 0, 1.0f, 0 };
//旧化
const float colormatrix_huajiu[] = {
0.2f,0.5f, 0.1f, 0, 40.8f,
0.2f, 0.5f, 0.1f, 0, 40.8f,
0.2f,0.5f, 0.1f, 0, 40.8f,
0, 0, 0, 1, 0 };
//哥特
const float colormatrix_gete[] = {
1.9f,-0.3f, -0.2f, 0,-87.0f,
-0.2f, 1.7f, -0.1f, 0, -87.0f,
-0.1f,-0.6f, 2.0f, 0, -87.0f,
0, 0, 0, 1.0f, 0 };
//锐色
const float colormatrix_ruise[] = {
4.8f,-1.0f, -0.1f, 0,-388.4f,
-0.5f,4.4f, -0.1f, 0,-388.4f,
-0.5f,-1.0f, 5.2f, 0,-388.4f,
0, 0, 0, 1.0f, 0 };
//淡雅
const float colormatrix_danya[] = {
0.6f,0.3f, 0.1f, 0,73.3f,
0.2f,0.7f, 0.1f, 0,73.3f,
0.2f,0.3f, 0.4f, 0,73.3f,
0, 0, 0, 1.0f, 0 };
//酒红
const float colormatrix_jiuhong[] = {
1.2f,0.0f, 0.0f, 0.0f,0.0f,
0.0f,0.9f, 0.0f, 0.0f,0.0f,
0.0f,0.0f, 0.8f, 0.0f,0.0f,
0, 0, 0, 1.0f, 0 };
//清宁
const float colormatrix_qingning[] = {
0.9f, 0, 0, 0, 0,
0, 1.1f,0, 0, 0,
0, 0, 0.9f, 0, 0,
0, 0, 0, 1.0f, 0 };
//浪漫
const float colormatrix_langman[] = {
0.9f, 0, 0, 0, 63.0f,
0, 0.9f,0, 0, 63.0f,
0, 0, 0.9f, 0, 63.0f,
0, 0, 0, 1.0f, 0 };
//光晕
const float colormatrix_guangyun[] = {
0.9f, 0, 0, 0, 64.9f,
0, 0.9f,0, 0, 64.9f,
0, 0, 0.9f, 0, 64.9f,
0, 0, 0, 1.0f, 0 };
//蓝调
const float colormatrix_landiao[] = {
2.1f, -1.4f, 0.6f, 0.0f, -31.0f,
-0.3f, 2.0f, -0.3f, 0.0f, -31.0f,
-1.1f, -0.2f, 2.6f, 0.0f, -31.0f,
0.0f, 0.0f, 0.0f, 1.0f, 0.0f
};
//梦幻
const float colormatrix_menghuan[] = {
0.8f, 0.3f, 0.1f, 0.0f, 46.5f,
0.1f, 0.9f, 0.0f, 0.0f, 46.5f,
0.1f, 0.3f, 0.7f, 0.0f, 46.5f,
0.0f, 0.0f, 0.0f, 1.0f, 0.0f
};
//夜色
const float colormatrix_yese[] = {
1.0f, 0.0f, 0.0f, 0.0f, -66.6f,
0.0f, 1.1f, 0.0f, 0.0f, -66.6f,
0.0f, 0.0f, 1.0f, 0.0f, -66.6f,
0.0f, 0.0f, 0.0f, 1.0f, 0.0f
};
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