CGRect Tips for use

In iOS development, we often need to deal with points, sizes and rectangles, the corresponding data structure is cgpoint,cgsize,cgrect, these data structures are C structure, the definition is as follows:

Cgpoint {  cgfloat x;  CGFloat y;}; cgsize {  cgfloat width;  CGFloat height;}; struct CGRect {  cgpoint origin;  Cgsize size;};

There are some handy ways to manipulate these data structures, as summarized below:

1. Create Cgpoint,cgsize,cgrect

Cgsize size = Cgsizemake (10.020.0= Cgpointmake (60.0240.0  = CGRectMake (5.010.0100.0200.0);

Some special cases
0 o ' Cgpointzero; i.e. (x=0.0, y=0.0), equivalent to Gpointmake (0,0);
0 size Cgsizezero; i.e. (width=0.0, height= 0.0), equivalent to Cgsizemake (0,0);
0 Rectangle Cgrectzero; i.e. ((x=0.0,y= 0.0), (width=0.0,height=0.0)), equivalent to CGRectMake (0,0,0,0).
Empty rectangular cgrectnull; The intersection of two disjoint rectangles returns Cgrectnull, and the cgrectnull of a rectangle is the original rectangle. , use Cgrectisnull to determine if a rectangle is cgrectnull. Cgrectisempty returns true for both Cgrectzero and cgrectnull;
The infinite rectangle cgrectinfinite has an infinite area of the rectangle, which can be judged using Cgrectisinfinite.

2. Determine two points, size, whether the rectangle is equal

BOOL Cgpointequaltopoint (Cgpoint point1, Cgpoint point2); BOOL cgsizeequaltosize (cgsize size1, cgsize size2); BOOL Cgrectequaltorect (CGRect rect1, CGRect rect2);

Cgpoint,cgsize,cgrect internal data are cgpoint, for floating-point numbers, because there may be rounding errors, can not directly determine whether the two are equal, but should determine whether the difference between the two values is small enough. Using the above method avoids making these judgments by hand and simplifying the code.

3. Get rectangle boundary, midpoint coordinate value, length width

1) Gets the boundary coordinate value, which is the maximum and minimum value of x, y .

CGFloat Cgrectgetminx (CGRect rect); CGFloat Cgrectgetmaxx (CGRect rect); CGFloat cgrectgetminy (CGRect rect); CGFloat cgrectgetmaxy (CGRect rect);

2) Gets the midpoint coordinate value, which is the midpoint of X, y

CGFloat cgrectgetmidx (CGRect rect); CGFloat cgrectgetmidy (CGRect rect);

3) Get rectangle length, Width

CGFloat cgrectgetwidth (CGRect rect); CGFloat cgrectgetheight (CGRect rect);

4. Symmetrical indent CGRect

CGRect arectangle = CGRectMake (0,0); // result origin (ten) and size (+)

5. Asymmetric indent CGRect

CGRect rect = CGRectMake (00= Uiedgeinsetsmake (20  uiedgeinsetsinsetrect= (rect, contentinsets); // result Origin (20,10) and size (40,160)

6. Adjust fractional pixels cgrect to integer pixels

The origin value is adjusted downward to the nearest integer, and size is adjusted upward to the nearest integer so that the resulting cgrect can fully contain the original cgrect.

CGRect rect = CGRectMake (57.5= Uiedgeinsetsmake (20  += cgrectintegral (rect); // result Origin (5,7) and size (50,30)

7. Check if the rectangle contains a point

CGRect enemyrect = CGRectMake (00= Cgpointmake (50 ); if (Cgrectcontainspoint (Enemyrect, hitPoint))    {        //  yes!}

8. Check whether the two rectangles intersect

CGRect playerrect = Ccrectmake (a);     = CGRectMake (ten);     if (Cgrectintersectsrect (Playerrect, minerect))    {        //  ouch!    }

9. CGRect and NSString Conversion

CGRect rect = CGRectMake (00);    *rectstring = nsstringfromcgrect (rect))   = cgrectfromstring (rectstring);

10.CGRect and Nsdictionary Conversion

CGRect rect = CGRectMake (00=  Cgrectcreatedictionaryrepresentation (rect); Nsdictionary//  autoreleasedcfrelease (framedictref); NSLog (@ "%@"&rect);

CGRect and Nsvalue Conversion

Only OBJETIVE-C objects can be stored in the Nsarray,nsdictionary container, and C structures cannot be stored directly, and all need to be converted to Nsvalue values when the rectangle needs to be stored.

CGRect rect = CGRectMake (00*value == [value Cgrectvalue] ;

CGRect Tips for use