//遍历图片像素，更改图片颜色
void
ProviderReleaseData (
void
*info,
const
void
*data,
size_t
size)
{
free
((
void
*)data);
}
– (
UIImage
*) imageBlackToTransparent:(
UIImage
*) image
{
//
分配内存
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);
//
创建
context
CGColorSpaceRef
colorSpace =
CGColorSpaceCreateDevice
RGB
();
CGContextRef
context =
CGBitmapContextCreate
(rgbImageBuf, imageWidth, imageHeight,
8
, bytesPerRow, colorSpace,
kCGBitmapByteOrder32Litt
le
|
kCGImageAlphaNoneSkipLas
t
);
CGContextDrawImage
(context,
CGRectMake
(
0
,
0
, imageWidth, imageHeight), image.
CGImage
);
//
遍历像素
int
pixelNum = imageWidth * imageHeight;
uint32_t
* pCurPtr = rgbImageBuf;
for
(
int
i =
0
; i < pixelNum; i++, pCurPtr++)
{
if
((*pCurPtr &
0xFFFFFF00
) ==
0xffffff00
)
//
将白色变成透明
{
uint8_t
* ptr = (
uint8_t
*)pCurPtr;
ptr[
0
] =
0
;
}
else
{
//
改成下面的代码，会将图片转成想要的颜色
uint8_t
* ptr = (
uint8_t
*)pCurPtr;
ptr[
3
] =
0
;
//0~255
ptr[
2
] =
0
;
ptr[
1
] =
0
;
}
}
//
将内存转成
image
CGDataProviderRef
dataProvider =
CGDataProviderCreateWith
Data
(
NULL
, rgbImageBuf, bytesPerRow * imageHeight,
ProviderReleaseData
);
CGImageRef
imageRef =
CGImageCreate
(imageWidth, imageHeight,
8
,
32
, bytesPerRow, colorSpace,
kCGImageAlphaLast
|
kCGBitmapByteOrder32Litt
le
, dataProvider,
NULL
,
true
,
kCGRenderingIntentDefaul
t
);
CGDataProviderRelease
(dataProvider);
UIImage
* resultUIImage = [
UIImage
imageWithCGImage
:imageRef];
//
释放
CGImageRelease
(imageRef);
CGContextRelease
(context);
CGColorSpaceRelease
(colorSpace);
// free(rgbImageBuf)
创建
dataProvider
时已提供释放函数，这里不用
free
return
resultUIImage;
}
//设置图片透明度
– (
UIImage
*)imageByApplyingAlpha:(
CGFloat
)alpha
image:(
UIImage
*)image
{
UIGraphicsBeginImageCont
extWithOptions
(image.
size
,
NO
,
0.0f
);
CGContextRef
ctx =
UIGraphicsGetCurrentCont
ext
();
CGRect
area =
CGRectMake
(
0
,
0
, image.
size
.
width
, image.
size
.
height
);
CGContextScaleCTM
(ctx,
1
, –
1
);
CGContextTranslateCTM
(ctx,
0
, -area.
size
.
height
);
CGContextSetBlendMode
(ctx,
kCGBlendModeMultiply
);
CGContextSetAlpha
(ctx, alpha);
CGContextDrawImage
(ctx, area, image.
CGImage
);
UIImage
*newImage =
UIGraphicsGetImageFromCu
rrentImageContext
();
UIGraphicsEndImageContex
t
();
return
newImage;
}
//合并2张图片
– (
UIImage
*)addImage:(
UIImage
*)image1 toImage:(
UIImage
*)image2 {
UIGraphicsBeginImageCont
ext
(image2.
size
);
// Draw image1
[image1
drawInRect
:
CGRectMake
(
0
,
0
, image1.
size
.
width
, image1.
size
.
height
)];
// Draw image2
[image2
drawInRect
:
CGRectMake
(
0
,
0
, image2.
size
.
width
, image2.
size
.
height
)];
UIImage
*resultingImage =
UIGraphicsGetImageFromCu
rrentImageContext
();
UIGraphicsEndImageContex
t
();
return
resultingImage;
}
//
将
UIImage
缩放到指定大小尺寸：
– (
UIImage
*)scaleToSize:(
UIImage
*)img size:(
CGSize
)size{
//
创建一个
bitmap
的
context
//
并把它设置成为当前正在使用的
context
UIGraphicsBeginImageCont
ext
(size);
//
绘制改变大小的图片
[img
drawInRect
:
CGRectMake
(
0
,
0
, size.
width
, size.
height
)];
//
从当前
context
中创建一个改变大小后的图片
UIImage
* scaledImage =
UIGraphicsGetImageFromCu
rrentImageContext
();
//
使当前的
context
出堆栈
UIGraphicsEndImageContex
t
();
//
返回新的改变大小后的图片
return
scaledImage;
}
//
根据图片的大小等比例压缩返回图片
-(
UIImage
*)fitSmallImage:(
UIImage
*)image size:(
CGSize
)size
{
if
(
nil
== image)
{
return
nil
;
}
if
(image.
size
.
width
<<span class=”s5″>200 && image.
size
.
height
<<span class=”s5″>200)
{
return
image;
}
UIGraphicsBeginImageCont
ext
(size);
CGRect
rect =
CGRectMake
(
0
,
0
, size.
width
, size.
height
);
[image
drawInRect
:rect];
UIImage
*newing =
UIGraphicsGetImageFromCu
rrentImageContext
();
UIGraphicsEndImageContex
t
();
return
newing;
}