【移動應用開發(fā)技術】iOS如何實現(xiàn)去除圖片背景顏色

/upload/information/20200623/126/120316.png-

(UIImage

*)removeColorWithMinHueAngle:(float)minHueAngle

maxHueAngle:(float)maxHueAngle

image:(UIImage

*)originalImage{

CIImage

*image

=

[CIImage

imageWithCGImage:originalImage.CGImage];

CIContext

*context

=

[CIContext

contextWithOptions:nil];//

kCIContextUseSoftwareRenderer

:

CPURender

/**

注意

*

UIImage

通過CIimage初始化，得到的并不是一個通過類似CGImage的標準UIImage

*

所以如果不用context進行渲染處理，是沒辦法正常顯示的

*/

CIImage

*renderBgImage

=

[self

outputImageWithOriginalCIImage:image

minHueAngle:minHueAngle

maxHueAngle:maxHueAngle];

CGImageRef

renderImg

=

[context

createCGImage:renderBgImage

fromRect:image.extent];

UIImage

*renderImage

=

[UIImage

imageWithCGImage:renderImg];

return

renderImage;

}

struct

CubeMap

{

int

length;

float

dimension;

float

*data;

};

-

(CIImage

*)outputImageWithOriginalCIImage:(CIImage

*)originalImage

minHueAngle:(float)minHueAngle

maxHueAngle:(float)maxHueAngle{

struct

CubeMap

map

=

createCubeMap(minHueAngle,

maxHueAngle);

const

unsigned

int

size

=

64;

//

Create

memory

with

the

cube

data

NSData

*data

=

[NSData

dataWithBytesNoCopy:map.data

length:map.length

freeWhenDone:YES];

CIFilter

*colorCube

=

[CIFilter

filterWithName:@"CIColorCube"];

[colorCube

setValue:@(size)

forKey:@"inputCubeDimension"];

//

Set

data

for

cube

[colorCube

setValue:data

forKey:@"inputCubeData"];

[colorCube

setValue:originalImage

forKey:kCIInputImageKey];

CIImage

*result

=

[colorCube

valueForKey:kCIOutputImageKey];

return

result;

}

struct

CubeMap

createCubeMap(float

minHueAngle,

float

maxHueAngle)

{

const

unsigned

int

size

=

64;

struct

CubeMap

map;

map.length

=

size

*

size

*

size

*

sizeof

(float)

*

4;

map.dimension

=

size;

float

*cubeData

=

(float

*)malloc

(map.length);

float

rgb[3],

hsv[3],

*c

=

cubeData;

for

(int

z

=

0;

z

<

size;

z++){

rgb[2]

=

((double)z)/(size-1);

//

Blue

value

for

(int

y

=

0;

y

<

size;

y++){

rgb[1]

=

((double)y)/(size-1);

//

Green

value

for

(int

x

=

0;

x

<

size;

x

++){

rgb[0]

=

((double)x)/(size-1);

//

Red

value

rgbToHSV(rgb,hsv);

//

Use

the

hue

value

to

determine

which

to

make

transparent

//

The

minimum

and

maximum

hue

angle

depends

on

//

the

color

you

want

to

remove

float

alpha

=

(hsv[0]

>

minHueAngle

&&

hsv[0]

<

maxHueAngle)

?

0.0f:

1.0f;

//

Calculate

premultiplied

alpha

values

for

the

cube

c[0]

=

rgb[0]

*

alpha;

c[1]

=

rgb[1]

*

alpha;

c[2]

=

rgb[2]

*

alpha;

c[3]

=

alpha;

c

+=

4;

//

advance

our

pointer

into

memory

for

the

next

color

value

}

}

}

map.data

=

cubeData;

return

map;

}void

rgbToHSV(float

*rgb,

float

*hsv)

{

float

min,

max,

delta;

float

r

=

rgb[0],

g

=

rgb[1],

b

=

rgb[2];

float

*h

=

hsv,

*s

=

hsv

+

1,

*v

=

hsv

+

2;

min

=

fmin(fmin(r,

g),

b

);

max

=

fmax(fmax(r,

g),

b

);

*v

=

max;

delta

=

max

-

min;

if(

max

!=

0

)

*s

=

delta

/

max;

else

{

*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;

}/upload/information/20200623/126/120317.jpg[[SPImageChromaFilterManager

sharedManager]

removeColorWithMinHueAngle:50

maxHueAngle:170

image:[UIImage

imageWithContentsOfFile:[[NSBundle

mainBundle]

pathForResource:@"nb"

ofType:@"jpeg"]]]/upload/information/20200623/126/120318.pngBitmap/upload/information/20200623/126/120319.jpg32-bit

and

16-bit

pixel

formats

for

CMYK

and

RGB

color

spaces

in

Quartz

2D-

(UIImage

*)removeColorWithMaxR:(float)maxR

minR:(float)minR

maxG:(float)maxG

minG:(float)minG

maxB:(float)maxB

minB:(float)minB

image:(UIImage

*)image{

//

分配內(nèi)存

const

int

imageWidth

=

image.size.width;

const

int

imageHeight

=

image.size.height;

size_t

bytesPerRow

=

imageWidth

*

4;

uint32_t*

rgbImageBuf

=

(uint32_t*)malloc(bytesPerRow

*

imageHeight);

//

創(chuàng)建context

CGColorSpaceRef

colorSpace

=

CGColorSpaceCreateDeviceRGB();//

色彩范圍的容器

CGContextRef

context

=

CGBitmapContextCreate(rgbImageBuf,

imageWidth,

imageHeight,

8,

bytesPerRow,

colorSpace,kCGBitmapByteOrder32Little

|

kCGImageAlphaNoneSkipLast);

CGContextDrawImage(context,

CGRectMake(0,

0,

imageWidth,

imageHeight),

image.CGImage);

//

遍歷像素

int

pixelNum

=

imageWidth

*

imageHeight;

uint32_t*

pCurPtr

=

rgbImageBuf;

for

(int

i

=

0;

i

<

pixelNum;

i++,

pCurPtr++)

{

uint8_t*

ptr

=

(uint8_t*)pCurPtr;

if

(ptr[3]

>=

minR

&&

ptr[3]

<=

maxR

&&

ptr[2]

>=

minG

&&

ptr[2]

<=

maxG

&&

ptr[1]

>=

minB

&&

ptr[1]

<=

maxB)

{

ptr[0]

=

0;

}else{

printf("\n>ptr0:%d

ptr1:%d

ptr2:%d

ptr3:%d<\n",ptr[0],ptr[1],ptr[2],ptr[3]);

}

}

//

將內(nèi)存轉(zhuǎn)成image

CGDataProviderRef

dataProvider

=CGDataProviderCreateWithData(NULL,

rgbImageBuf,

bytesPerRow

*

imageHeight,

nil);

CGImageRef

imageRef

=

CGImageCreate(imageWidth,

imageHeight,8,

32,

bytesPerRow,

colorSpace,kCGImageAlphaLast

|kCGBitmapByteOrder32Little,

dataProvider,NULL,true,kCGRenderingIntentDefault);

CGDataProviderRelease(dataProvider);

UIImage*

resultUIImage

=

[UIImage

imageWithCGImage:imageRef];

//

釋放

CGImageRelease(imageRef);

CGContextRelease(context);

CGColorSpaceRelease(colorSpace);

return

resultUIImage;

}-

(UIImage

*)removeWhiteColorWithImage:(UIImage

*)image{

return

[self

removeColorWithMaxR:255

minR:250

maxG:255

minG:240

maxB:255

minB:240

image:image];

}-

(UIImage

*)removeBlackColorWithImage:(UIImage

*)image{

return

[self

removeColorWithMaxR:15

minR:0

maxG:15

minG:0

maxB:15

minB:0

image:image];

}/upload/information/20200623/126/120322.png/upload/information/20200623/126/120325.png/upload/information/20200623/126/120328.png/upload/information/20200623/126/120329.jpg-

(UIImage

*)removeColorWithMaxR:(float)maxR

minR:(float)min