Using IOS to draw pictures to generate random Captcha sample code _ios

Let's take a look at the effect chart.

Implementation methods

. h Files

@property (nonatomic, retain) Nsarray *changearray;
@property (nonatomic, retain) nsmutablestring *changestring;
@property (nonatomic, retain) Uilabel *codelabel;

-(void) ChangeCode;
@end

. m file

@synthesize Changearray = _changearray;
@synthesize changestring = _changestring;

@synthesize Codelabel = _codelabel;
  -(ID) initWithFrame: (CGRect) frame {self = [super Initwithframe:frame];
    if (self) {//initialization code FLOAT red = arc4random ()% 100/100.0;
    float green = arc4random ()% 100/100.0;
    float blue = arc4random ()% 100/100.0;
    Uicolor *color = [Uicolor colorwithred:red green:green blue:blue alpha:0.2];
    Self.backgroundcolor = color;
  [Self change];
return self;
  }-(void) ChangeCode {[Self change];
[Self setneedsdisplay]; }-(void) Change {self.changearray = [[Nsarray alloc] initwithobjects:@ "0", @ "1", @ "2", @ "3", @ "4", @ "5", @ "6", @ "7", @ "8", @ " 9 ", @" A ", @" B ", @" C ", @" D ", @" E ", @" F ", @" G ", @" H ", @" I ", @" J ", @" K ", @" L ", @" M ", @" N ", @" O ", @" P ", @" Q ", @" R ", @" S ", @" T ", @" U ", @" V ", @" W ", @" X ", @" Y ", @" Z ", @" a ", @" B ", @" C ", @" D ", @" E ", @" F ", @" G ", @" H ", @" I ", @" J ", @" K ", @" L ", @" M ", @" n ", @" O ", @" P ", @" Q ", @"

  R ", @" s ", @" T ", @" U ", @" V ", @" W ", @" x ", @" Y ", @" Z ", Nil]; Nsmutablestring *GETSTR = [[Nsmutablestring alloc] initwithcapacity:5];
  self.changestring = [[Nsmutablestring alloc] initwithcapacity:6];
    for (Nsinteger i = 0; i < 4; i++) {Nsinteger index = arc4random ()% ([Self.changearray count]-1);

    GETSTR = [Self.changearray objectatindex:index];
  self.changestring = (nsmutablestring *) [self.changestring stringbyappendingstring:getstr];

  }}-(void) DrawRect: (cgrect) rect {[Super Drawrect:rect];
  float red = arc4random ()% 100/100.0;
  float green = arc4random ()% 100/100.0;

  float blue = arc4random ()% 100/100.0;
  Uicolor *color = [Uicolor colorwithred:red green:green blue:blue alpha:0.5];

  [Self setbackgroundcolor:color];
  NSString *text = [NSString stringwithformat:@ "%@", self.changestring];
  Cgsize csize = [@ "S" Sizewithattributes:@{nsfontattributename:[uifont systemfontofsize:20]}];
  int width = rect.size.width/text.length-csize.width;
  int height = rect.size.height-csize.height;

  Cgpoint Point; Float PX,PY;
    for (int i = 0; i < text.length i++) {PX = Arc4random ()% width + rect.size.width/text.length * i;
    PY = arc4random ()% height;
    Point = Cgpointmake (PX, PY);
    Unichar c = [text Characteratindex:i];
    NSString *TEXTC = [NSString stringwithformat:@ "%c", C];
  [TEXTC drawatpoint:point Withattributes:@{nsfontattributename:[uifont systemfontofsize:20]}];
  } cgcontextref context = Uigraphicsgetcurrentcontext ();
  Cgcontextsetlinewidth (context, 1.0);
    for (int cout = 0; cout < cout++) {red = Arc4random ()% 100/100.0;
    Green = arc4random ()% 100/100.0;
    Blue = arc4random ()% 100/100.0;
    color = [Uicolor colorwithred:red green:green blue:blue alpha:0.2];
    Cgcontextsetstrokecolorwithcolor (context, [color Cgcolor]);
    PX = Arc4random ()% (int) rect.size.width;
    PY = Arc4random ()% (int) rect.size.height;
    Cgcontextmovetopoint (context, PX, PY);
    PX = Arc4random ()% (int) rect.size.width; PY = Arc4random ()% (int) Rect.sIze.height;
    Cgcontextaddlinetopoint (context, PX, PY);
  Cgcontextstrokepath (context); }} @end

Called in Viewcontroller

_codeview = [[CodeView alloc] Initwithframe:cgrectmake (15+ (screen_width-30)/3*2, (screen_width-30)/3, M)];
 Gesture
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initwithtarget:self action: @selector (Tapclick :)];
[_codeview Addgesturerecognizer:tap];
[Self.view addsubview: _codeview];

Gesture Events

-(void) Tapclick: (uitapgesturerecognizer*) Tap
{
  [_codeview ChangeCode];
}

Summarize

The above is the use of iOS to draw pictures random verification code of the entire content, I hope this article on the content of iOS developers can help, if you have questions you can message exchange.