Object-c image compression-pixel compression and non-pixel compression

/* * @brief compress picture @Fire * * @param originimage Original image * @param pc is pixel compressed * @param the maximum pixel length and width of maxpixel after compression; Pc=no, this parameter is invalid. * @param JC is JPEG compressed * @param maxkb Picture maximum volume, in kilobytes, this parameter is invalid when Jc=no. * * @return return picture of NSData */-(nsdata*) Compressimage: (uiimage*) originimage pixelcompress: (BOOL) PC Maxpixel: (cgfloat) Maxpixel jpegcompress: (BOOL) JC maxsize_kb: (cgfloat) maxkb;

-(nsdata*) Compressimage: (uiimage*) originimage pixelcompress: (BOOL) PC Maxpixel: (cgfloat) Maxpixel JPEGCompress: ( BOOL) JC maxsize_kb: (cgfloat) maxkb{/* Compression policy: Supports up to 921,600 pixel pixel compression: (number of pixel points) when the picture aspect ratio is less than 3:1 or 1:3, the picture            The length and width are up to maxpixel pixels, and when the picture aspect ratio is between 3:1 and 1:3, the picture pixels are compressed to within 921600 pixels; JPEG compression: (Adjusts the storage volume per pixel) By default compression ratio 0.99;     If the compressed data is still greater than image_max_bytes, then the compression ratio will be compressed to image_max_bytes the picture below.        Policy tuning: No pixel compression, or increased maxpixel, the smaller the pixel loss.     Use lossless compression, or increase image_max_bytes.     Note: When the JEPG compression ratio is 0.99, the image volume can be compressed to 0.40 times times the original.    */UIImage * scopedimage = nil;    NSData * data = nil;    CGFloat maxbytes = maxkb * 1024;    if (originimage = = nil) {return nil; } if (PC = = YES) {//pixel compression//Pixel count is maxpixel*maxpixel cgfloat photoratio = OriginImage.size.heig        Ht/originimage.size.width; if (Photoratio < 0.3333f) {//solve the problem of wide-length graphs cgfloat finalwidth = sqrt (maxpix El*maxpixel/photoratio);        Scopedimage = [Encodeutil convertimage:originimage scope:max (Finalwidth, Maxpixel)]; } else if (Photoratio <= 3.0f) {//Solve high-length graph problem scopedimage = [Encodeut        Il convertimage:originimage scope:maxpixel]; } else {//general picture CGFloat finalheight = sqrt (maxpixel*maxpixel*photorat            IO);        Scopedimage = [Encodeutil convertimage:originimage scope:max (Finalheight, Maxpixel)];    }} else {//do not pixel compression scopedimage = originimage;        } [Scopedimage retain];        if (JC = = YES) {//jpeg Compressed data = UIImageJPEGRepresentation (Scopedimage, 0.8);    NSLog (@ "Data compress with ratio (0.9):%d KB", data.length/1024);        } else {data = UIImageJPEGRepresentation (Scopedimage, 1.0);    NSLog (@ "Data compress:%d KB", data.length/1024);        } [Scopedimage release]; return data;}

ENCODEUTIL.M implementation

+ (UIImage *) Convertimage: (UIImage *) origimage scope: (cgfloat) scope{UIImage *image = nil;    Cgsize size = origimage.size;    if (Size.width < scope && Size.Height < scope) {//do nothing image = Origimage;        } else {cgfloat length = size.width;        if (Size.width < size.height) {length = Size.Height;        } cgfloat f = scope/length;        Nsinteger NW = size.width * F;        Nsinteger NH = size.height * F;        if (NW > scope) {NW = scope;        } if (NH > Scope) {NH = scope;                } cgsize newSize = Cgsizemake (NW, NH);//Cgsize newSize = Cgsizemake (size.width*f, size.height*f);        Uigraphicsbeginimagecontext (newSize);        Uigraphicsbeginimagecontextwithoptions (NewSize, NO, 0.0f); Tell the old image to draw in this new context, with the desired//new size [Origimage Drawinrect:cgrec Tmake (0, 0, Newsize.width,Newsize.height)];        Get the new image from the context image = Uigraphicsgetimagefromcurrentimagecontext ();     Uigraphicsendimagecontext (); } return image;

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Object-c image compression-pixel compression and non-pixel compression