从UIImage/CGImage到Leptonica Pix结构的转换
从UIImage/CGImage到Leptonica Pix结构的转换
提问于 2012-02-01 02:57:18
我想在我的iOS应用程序中使用Leptonica库进行图像处理，但在如何从UIImage获取Leptonica的Pix结构时遇到了麻烦。我建议这样做：
UIImage *image = [UIImage imageNamed:@"test.png"];
...
CFDataRef imageData = CGDataProviderCopyData(CGImageGetDataProvider([image CGImage]));
const UInt8 *rasterData = CFDataGetBytePtr(data);有没有人可以建议如何正确地将这些数据转换为Leptonica的Pix结构：
/*-------------------------------------------------------------------------*
* Basic Pix *
*-------------------------------------------------------------------------*/
struct Pix
{
l_uint32 w; /* width in pixels */
l_uint32 h; /* height in pixels */
l_uint32 d; /* depth in bits */
l_uint32 wpl; /* 32-bit words/line */
l_uint32 refcount; /* reference count (1 if no clones) */
l_int32 xres; /* image res (ppi) in x direction */
/* (use 0 if unknown) */
l_int32 yres; /* image res (ppi) in y direction */
/* (use 0 if unknown) */
l_int32 informat; /* input file format, IFF_* */
char *text; /* text string associated with pix */
struct PixColormap *colormap; /* colormap (may be null) */
l_uint32 *data; /* the image data */
};更新：
我是这样做的：
UIImage *image = [UIImage imageNamed:@"test.png"];
CFDataRef data = CGDataProviderCopyData(CGImageGetDataProvider([image CGImage]));
const UInt8 *imageData = CFDataGetBytePtr(data);
Pix *myPix = (Pix *) malloc(sizeof(Pix));
CGImageRef myCGImage = [image CGImage];
myPix->w = CGImageGetWidth (myCGImage);
myPix->h = CGImageGetHeight (myCGImage);
myPix->d = CGImageGetBitsPerComponent(myCGImage);
myPix->wpl = CGImageGetBytesPerRow (myCGImage) / 4;
myPix->data = (l_uint32 *) imageData;
myPix->colormap = NULL;
NSLog(@"pixWrite=%d", pixWrite("/tmp/lept-res.bmp", myPix, IFF_BMP));但我得到的与原始图片有很大不同：
http://dl.dropbox.com/u/4409984/so/lept-orig.png
与
http://dl.dropbox.com/u/4409984/so/lept-res.png
我做错了什么？
回答 2
Stack Overflow用户
回答已采纳
发布于 2012-02-01 03:09:03
一旦有了CGImage，您就可以直接从CGImage获取大部分信息。
CGImageRef myCGImage = [image CGImage];
struct Pix myPix;
myPix.w = CGImageGetWidth (myCGImage);
myPix.h = CGImageGetHeight (myCGImage);
myPix.d = CGImageGetBitsPerComponent (myCGImage);
myPix.wpl = CGImageGetBytesPerRow (myCGImage) / 4;
... etc. ...Stack Overflow用户
发布于 2012-02-28 17:34:38
尝试以下代码：
CFDataRef data = CGDataProviderCopyData(CGImageGetDataProvider([picture CGImage]));
const UInt8 *imageData = CFDataGetBytePtr(data);
Pix *myPix = (Pix *) malloc(sizeof(Pix));
CGImageRef myCGImage = [picture CGImage];
myPix->w = CGImageGetWidth (myCGImage);
myPix->h = CGImageGetHeight (myCGImage);
myPix->d = CGImageGetBitsPerPixel([picture CGImage]) ;
myPix->wpl = CGImageGetBytesPerRow (myCGImage)/4 ;
myPix->data = (l_uint32 *) imageData;
myPix->colormap = NULL;
pixEndianByteSwap(myPix);
NSLog(@"pixWrite=%d", pixWrite("/tmp/lept-res.bmp", myPix, IFF_BMP));页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/9085236
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