iOS 關於UIImage的處理總結

void providerreleasedata (void *info, const void *data, size_t size)

- (uiimage*)imageblacktotransparent:(uiimage*)image weight:(nsinteger)weight

//// else
//// 
}// 將記憶體轉成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];
// 釋放
cgimagerelease(imageref);
cgcontextrelease(context);
cgcolorspacerelease(colorspace);
// free(rgbimagebuf) 建立dataprovider時已提供釋放函式，這裡不用free
return resultuiimage;
}

-(nsdictionary*)mostcolorfromimage:(uiimage *)image

#pragma mark - 合併2張
- (uiimage *)addimage:(uiimage *)image1 toimage:(uiimage *)image2

#pragma mark - 將uiimage縮放到指定大小尺寸

- (uiimage *)scaletosize:(uiimage *)img size:(cgsize)size

#pragma mark - 根據的大小等比例壓縮返回

-(uiimage *)fitsmallimage:(uiimage *)image size:(cgsize)size

if (image.size.width&&image.size.height)
uigraphicsbeginimagecontext(size);
cgrect rect = cgrectmake(0, 0, size.width, size.height);
[image drawinrect:rect];
uiimage *newing = uigraphicsgetimagefromcurrentimagecontext();
uigraphicsendimagecontext();
return newing;
}

#pragma mark - 獲取點對應的顏色

+ (uicolor*) getpixelcoloratlocation:(cgpoint)point inimage:(uiimage *)image 

size_t w = cgimagegetwidth(inimage);
size_t h = cgimagegetheight(inimage);
cgrect rect = ,};
cgcontextdrawimage(cgctx, rect, inimage);
unsigned char* data = cgbitmapcontextgetdata (cgctx);
if (data != null) 
cgcontextrelease(cgctx);
if (data) 
return color;
}+ (cgcontextref) createargbbitmapcontextfromimage:(cgimageref) inimage 
bitmapdata = malloc( bitmapbytecount );
if (bitmapdata == null)
context = cgbitmapcontextcreate (bitmapdata,
pixelswide, 
pixelshigh, 
8, 
bitmapbytesperrow, 
colorspace, 
kcgimagealphapremultipliedfirst); 
if (context == null) 
cgcolorspacerelease( colorspace ); 
return context; 
}

參考文章

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