IOS中替换一张图片背景颜色的方法

http://blog.csdn.net/wutongpiaofei/article/details/37900213

分类： 疑难杂症2014-07-17
08:47 50人阅读 评论(0) 收藏 举报

ios7图片

//颜色替换
- (UIImage*) imageToTransparent:(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 = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(rgbImageBuf, imageWidth, imageHeight, 8,
bytesPerRow, colorSpace,
kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipLast);
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++)
{

//把绿色变成黑色，把背景色变成透明
if ((*pCurPtr & 0x65815A00) == 0x65815a00)
// 将背景变成透明
{
uint8_t* ptr = (uint8_t*)pCurPtr;
ptr[0] = 0;
}
else if ((*pCurPtr & 0x00FF0000) == 0x00ff0000)
// 将绿色变成黑色
{
uint8_t* ptr = (uint8_t*)pCurPtr;
ptr[3] = 0; //0~255
ptr[2] = 0;
ptr[1] = 0;
}
else 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 =CGDataProviderCreateWithData(NULL,
rgbImageBuf, bytesPerRow * imageHeight, ProviderReleaseData);
CGImageRef imageRef = CGImageCreate(imageWidth, imageHeight,8, 32,
bytesPerRow, colorSpace,
kCGImageAlphaLast |kCGBitmapByteOrder32Little, dataProvider,
NULL, true,kCGRenderingIntentDefault);

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;
}

/** 颜色变化 */
void ProviderReleaseData (void *info, const void *data, size_tsize)
{
free((void*)data);
}
http://blog.csdn.net/wutongpiaofei/article/details/37900213