How does an 'annot' CGPDFDictionary 'Rect' translate to objective c Rect

How does an 'annot' CGPDFDictionary '开发者_如何学CRect' translate to objective c Rect:

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Adobes PDF Spec states:

Rectangles are used to describe locations on a page and bounding boxes for a variety of objects. A rectangle shall be written as an array of four numbers giving the coordinates of a pair of diagonally opposite corners.

Although rectangles are conventionally specified by their lower-left and upper-right corners, it is acceptable to specify any two diagonally opposite corners. Applications that process PDF should be prepared to normalize such rectangles in situations where specific corners are required. Typically, the array takes the form [llx lly urx ury] specifying the lower-left x, lower-left y, upper-right x, and upper-right y coordinates of the rectangle, in that order. The other two corners of the rectangle are then assumed to have coordinates (llx, ury) and (urx, lly).

So, this means that that the rect translation is not native as shown here and should be like this:

CGRect rect = CGRectMake(coords[0],coords[3],coords[2]-coords[0],coords[3]-coords[1]);

See the code Bellow (original code by BrainFeeder) to see the context of the coords array:

CGPDFArrayRef rectArray;
                if(CGPDFDictionaryGetArray(annotDict, "Rect", &rectArray)) {
                    //continue;

                    CGPDFReal coords[4];

                    for( int k = 0; k < arrayCount; ++k ) {

                        CGPDFObjectRef rectObj;
                        if(!CGPDFArrayGetObject(rectArray, k, &rectObj)) {
                            continue;
                        }

                        CGPDFReal coord;
                        if(!CGPDFObjectGetValue(rectObj, kCGPDFObjectTypeReal, &coord)) {
                            continue;
                        }

                        coords[k] = coord;
                    }      

                }

                //blx,bly,trx,try>tlx,tly,w,h

                CGRect rect = CGRectMake(coords[0],coords[3],coords[2]-coords[0],coords[3]-coords[1]);