iOS development-Random image verification code

Sign-in in iOS projects often use random verification code, especially in the form of images generated by the code, you can reduce the use of third-party resources, only local generation and verification, this article describes the process of generating random picture verification code, including Arabic numerals 0-9, English capital letter A-Z, English lowercase letter A-Z, the generated captcha is case-sensitive. If you want to change to a case-insensitive, just need to add a judgment when the code is taken.

first, create a class that inherits from UIView and add the properties and methods required by the outside world in the. h file:

@property (Strong, nonatomic) nsmutablestring *authcodestr; // Verification Code String -(void) Getauthcode;

Second, add the macro definition in the. m file:

//Random background color#definekrandomcoloral [Uicolor colorwithred:arc4random ()% 256/256.0 green:arc4random ()% 256/256.0 blue:arc4random ()% 256 /256.0 alpha:0.5];//interference line Random color#defineKrandomcolor [Uicolor colorwithred:arc4random ()% 256/256.0 green:arc4random ()% 256/256.0 blue:arc4random ()% 256/ 256.0 Alpha:1];//number of interference lines#defineKlinecount 4//Interference line width#defineKlinewidth 1.0//number of verification codes#defineKcharcount 4//Verification Code size#defineKfontsize (Arc4random ()% 5 + 20)

Third, initialize:

- (Instancetype) initWithFrame: (cgrect) frame{    = [Super Initwithframe:frame];     if (self)    {        5.0f;         = YES;         = Krandomcolor;                [Self getauthcode]; // get a random verification code     }    return self ;}

Four, obtain the random verification code method:

#pragmaMark obtains a random verification code-(void) getauthcode{//string Footage_dataarray = [[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]; _authcodestr=[[Nsmutablestring alloc] initwithcapacity:kcharcount]; //randomly select the required number of strings from the array, stitching it into a CAPTCHA string     for(inti =0; i < Kcharcount; i++) {Nsinteger index= Arc4random ()% (_dataarray.count-1); NSString*tempstr =[_dataarray Objectatindex:index]; _authcodestr= (Nsmutablestring *) [_authcodestr stringbyappendingstring:tempstr]; }}

Five, click the interface Switch Verification code:

#pragma Mark Click Interface Switch Verification code-(void) Touchesbegan: (Nsset *) touches withevent: (uievent *)event {    [self getauthcode];         // Setneedsdisplay Call the DrawRect method to implement view rendering     [self setneedsdisplay];}

Six, Draw:

#pragmaMark Draw-(void) DrawRect: (CGRect) rect{[Super Drawrect:rect]; //set a random background colorSelf.backgroundcolor =krandomcoloral; //calculates the position of each string displayed according to the length of the CAPTCHA string to displayNSString *text = [NSString stringWithFormat:@"%@", _authcodestr]; Cgsize cSize= [@"A"Sizewithattributes:@{nsfontattributename:[uifont systemfontofsize: -]}]; intwidth = rect.size.width/text.length-Csize.width; intHeight = rect.size.height-Csize.height;        Cgpoint Point; //draw each character in turn to set the font size, color, style, and so on for each character displayed    floatpx,py;  for(inti =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]; Uifontdescriptor*attributefontdescriptor =[uifontdescriptor fontdescriptorwithfontattributes: @{uifontdescr Iptorfamilyattribute:@"Marion", Uifontdescriptornameattribute:@"HANZIPENSC-W3", Uifontdescriptorsizeattribute: @40.0, Uifontdescriptormatrixattribute:[nsvalue Valuewithcgaffinetran Sform:cgaffinetransformmakerotation (M_1_pi* (Arc4random ()%2 ))                                                                                        ]}]; Uifont* Font =[Uifont fontwithdescriptor:attributefontdescriptor size:kfontsize]; Uicolor*color =Krandomcolor;            [TEXTC Drawatpoint:point Withattributes:@{nsfontattributename:font,nsforegroundcolorattributename:color}]; }            //call DrawRect: Before the system pushes a cgcontextref into the stack, the call Uigraphicsgetcurrentcontext () takes the top of the stack cgcontextrefCgcontextref context =Uigraphicsgetcurrentcontext (); //Set line widthcgcontextsetlinewidth (context, klinewidth); //Draw Interference Lines     for(inti =0; i < Klinecount; i++) {Uicolor*color =Krandomcolor; Cgcontextsetstrokecolorwithcolor (context, color. Cgcolor);//Set line Fill Color//set the starting point of a linePX = Arc4random ()% (int) Rect.size.width; PY= Arc4random ()% (int) Rect.size.height;        Cgcontextmovetopoint (context, PX, PY); //set line end pointPX = Arc4random ()% (int) Rect.size.width; PY= Arc4random ()% (int) Rect.size.height;        Cgcontextaddlinetopoint (context, PX, PY); //Draw LineCgcontextstrokepath (context); }}

call, called in the class that needs to use the CAPTCHA:1. Define attributes:

@property (nonatomic, Strong) Maxauthcodeview * authcodeimage; /* *< Verification Code View */

2. Initialize:

Self.authcodeimage = [[Maxauthcodeview alloc] Initwithframe:cgrectmake (60 )];    [Self.view AddSubview:self.authcodeImage];    [Self.authcodeimage Getauthcode];

3. Get Verification Code:

NSLog (@ "%@", SELF.AUTHCODEIMAGE.AUTHCODESTR);

Eight, I hope you can get useful information, thank you!

Demo:https://github.com/maxli7681/authcode

iOS development-Random image verification code