[IOS UI advanced, iosui advanced

[IOS UI advanced, iosui advanced
A. Some details about Quiartz2D1. The UIKit tool has encapsulated context references, so you do not need to manually obtain and render them.

1 - (void)drawRect:(CGRect)rect {2     [[UIColor redColor] set];3     UIRectFill(CGRectMake(0, 0, 100, 100));4 }

1-(void) drawRect :( CGRect) rect {2 CGContextRef ctx = UIGraphicsGetCurrentContext (); 3 4 // 1.1 create the first path 5 CGMutablePathRef linePath = CGPathCreateMutable (); 6 7 // 1. 2. depict path 8 CGPathMoveToPoint (linePath, NULL, 0, 0); 9 CGPathAddLineToPoint (linePath, NULL, 100,100); 10 11 // 1. 3. add linePath to context 12 CGContextAddPath (ctx, linePath); 13 14 // 2 Add a circle path15 CGMutablePathRef circlePath = CGPathCreateMutable (); 16 rows (circlePath, NULL, CGRectMake (0, 0, 50, 50); 17 CGContextAddPath (ctx, circlePath); 18 19 // rendering context 20 CGContextStrokePath (ctx); 21 22 // release path23 CGPathRelease (linePath ); 24 CGPathRelease (circlePath); 25}1 // 2 // MyImageView. h 3 // MyImageView 4 // 5 // Created by hellovoidworld on 14/12/31. 6 // Copyright (c) 2014 hellovoidworld. all rights reserved. 7 // 8 9 # import <UIKit/UIKit. h> 10 11 @ interface MyImageView: UIView12 13 @ property (nonatomic, weak) UIImage * image; 14 15 @ end

 

1 // 2 // MyImageView. m 3 // MyImageView 4 // 5 // Created by hellovoidworld on 14/12/31. 6 // Copyright (c) 2014 hellovoidworld. all rights reserved. 7 // 8 9 # import "MyImageView. h "10 11 @ implementation MyImageView12 13-(void) setImage :( UIImage *) image {14 _ image = image; 15 16 // when the image is reset, redraw 17 [self setNeedsDisplay]; 18} 19 20-(void) drawRect :( CGRect) rect {21 [self. image drawInRect: rect]; 22} 23 24 @ end25 26 controller: 27-(void) viewDidLoad {28 [super viewDidLoad]; 29 // Do any additional setup after loading the view, typically from a nib.30 31 MyImageView * imageView = [[MyImageView alloc] init]; 32 imageView. frame = CGRectMake (0, 0,200,320); 33 [self. view addSubview: imageView]; 34 imageView. image = [UIImage imageNamed: @ "M4"]; 35}

1 // 2 // MyTextView. h 3 // MyTextField 4 // 5 // Created by hellovoidworld on 14/12/31. 6 // Copyright (c) 2014 hellovoidworld. all rights reserved. 7 // 8 9 # import <UIKit/UIKit. h> 10 11 @ interface MyTextView: UITextView12 13 @ property (nonatomic, copy) NSString * placeHolderText; 14 15 @ end 

1 // 2 // MyTextView. m 3 // MyTextField 4 // 5 // Created by hellovoidworld on 14/12/31. 6 // Copyright (c) 2014 hellovoidworld. all rights reserved. 7 // 8 9 # import "MyTextView. h "10 11 @ interface MyTextView () <UITextViewDelegate> 12 13/** original text color */14 @ property (nonatomic, weak) UIColor * originalTextColor; 15 16 @ end17 18 @ implementation MyTextView19 20 // rewrite the initialization method and set proxy 21-(instancetype) init {22 if (self = [super init]) {23 self. returnKeyType = UIReturnKeyDone; 24 self. delegate = self; 25} 26 27 return self; 28} 29 30 // when you reset placeHolderText, repaint the control 31-(void) setPlaceHolderText :( NSString *) placeHolderText {32 _ placeHolderText = placeHolderText; 33 [self setNeedsDisplay]; 34} 35 36 // start editing, remove placeHolder37-(BOOL) textViewShouldBeginEditing :( UITextView *) textView {38 if ([self. text isw.tostring: self. placeHolderText]) {39 self. text = nil; 40 self. textColor = self. originalTextColor; 41} 42 43 return YES; 44} 45 46 // end editing. If the text is empty, set placeHolder47-(void) textViewDidEndEditing :( UITextView *) textView {48 [self setNeedsDisplay]; 49} 50 51-(void) drawRect :( CGRect) rect {52 if (self. text. length = 0) {53 self. text = self. placeHolderText; 54 self. textColor = [UIColor grayColor]; 55} 56} 57 58 59 @ end

D. Image Watermark1. STEP (1) drag a UIImageView on the storyboard and create a bitmap-based context in the image context created by the Controller code --> the system creates a bitmap object, which is equivalent to creating a new UIImage object (2) painting background (3) watermarking (4) Obtaining the created UIImage object from the context (5) Ending image Context

1 // 2 // UIImage + HW. m 3 // Watermark 4 // 5 // Created by hellovoidworld on 14/12/31. 6 // Copyright (c) 2014 hellovoidworld. all rights reserved. 7 // 8 9 # import "UIImage + HW. h "10 11 @ implementation UIImage (HW) 12 13 + (instancetype) image :( NSString *) image withWatermark :( NSString *) watermark {14 // obtain the background image 15 UIImage * bgImage = [UIImage imageNamed: image]; 16 17 // 1. enable a bitmap Context 18 uigraphicsbeginimagecontextwitexceptions (bgImage. size, NO, 0.0); 19 20 // 2. add the background image to the position graph context 21 [bgImage drawInRect: CGRectMake (0, 0, bgImage. size. width, bgImage. size. height)]; 22 23 // 3. add watermark image 24 UIImage * watermarkImage = [UIImage imageNamed: watermark]; 25 CGFloat scale = 0.5; 26 CGFloat margin = 50; 27 CGFloat watermarkWidth = watermarkImage. size. width * scale; 28 CGFloat watermarkHeight = watermarkImage. size. width * scale; 29 CGFloat watermarkX = bgImage. size. width-watermarkWidth-margin; 30 CGFloat watermarkY = bgImage. size. height-watermarkHeight-margin; 31 [watermarkImage drawInRect: CGRectMake (watermarkX, watermarkY, watermarkWidth, watermarkHeight)]; 32 33 34 // 4. obtain the synthesized image 35 UIImage * resultImage = UIGraphicsGetImageFromCurrentImageContext (); 36 37 // 5. disable text context 38 UIGraphicsEndImageContext (); 39 40 return resultImage; 41} 42 43 @ end

(6) display to UIImageView

 1 - (void)viewDidLoad { 2     [super viewDidLoad]; 3     // Do any additional setup after loading the view, typically from a nib. 4     5     UIImage *watermarkedImage = [UIImage image:@"M4" withWatermark:@"a9ec8a13632762d0092abc3ca2ec08fa513dc619"]; 6     7     UIImageView *imageView = [[UIImageView alloc] initWithImage:watermarkedImage]; 8     imageView.frame = CGRectMake(0, 0, 200, 320); 9     [self.view addSubview:imageView];10 }

(7) Save image a. Compress image B. Write File

1 // The compressed image is a PNG binary data 2 NSData * data = UIImagePNGRepresentation (watermarkedImage); 3 4 // Write File 5 NSString * path = [inline (NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent: @ "watermarkedImage.png"]; 6 NSLog (@ "% @", path); 7 [data writeToFile: path atomically: YES];

1/** create a circular Avatar image with a specified width and color border */2 + (instancetype) imageOfCircleHeadIcon :( NSString *) image withBorderWidth :( CGFloat) borderWidth borderColor :( UIColor *) borderColor {3 // retrieve image 4 UIImage * headIconImage = [UIImage imageNamed: image]; 5 6 // enable image context 7 CGFloat backImageWidth = headIconImage. size. width + 2 * borderWidth; 8 CGFloat backImageHeight = headIconImage. size. height + 2 * borderWidth; 9 CGSize backImageSize = CGSizeMake (backImageWidth, backImageHeight); 10 bytes (backImageSize, NO, 0.0); 11 12 // depicts the background circle 13 [borderColor set]; // set the ring color 14 CGContextRef ctx = UIGraphicsGetCurrentContext (); 15 CGFloat backCircleRadius = backImageWidth * 0.5; // large circle radius 16 CGFloat backCircleX = backCircleRadius; // X17 CGFloat backCircleY = backCircleRadius; // Y18 percentile (ctx, backCircleX, backCircleY, round, 0, M_PI * 2, 0); 19 CGContextFillPath (ctx ); 20 21 // depict the circle 22 CGFloat border = backCircleRadius-borderWidth used to display the image; // The circle radius 23 CGFloat frontCircleX = backCircleX; 24 CGFloat frontCircleY = backCircleY; 25 (ctx, frontCircleX, frontCircleY, frontCircleRadius, 0, M_PI * 2, 0); 26 27 // crop (the image depicted later will be cropped) 28 CGContextClip (ctx ); 29 30 // Add the image to context 31 [headIconImage drawInRect: CGRectMake (borderWidth, borderWidth, headIconImage. size. width, headIconImage. size. height)]; 32 33 // get the synthesized image 34 UIImage * headIconResultImage = merged (); 35 36 // close the image context 37 UIGraphicsEndImageContext (); 38 39 return headIconResultImage; 40}1/** click "screen" */2-(IBAction) screenShotcut {3 // delay to prevent the status of the button being pressed when it is intercepted. 4 dispatch_after (dispatch_time (DISPATCH_TIME_NOW, (int64_t) (0.1 * NSEC_PER_SEC), dispatch_get_main_queue (), ^ {5 6 UIView * view = self. view; 7 8 // 1. enable bitmap Context 9 uigraphicsbeginimagecontextwitexceptions (view. frame. size, NO, 0.0); 10 11 // 2. rendering controller view layer to context 12 [view. layer renderInContext: UIGraphicsGetCurrentContext ()]; 13 14 // 3. obtain image 15 UIImage * screenImage = UIGraphicsGetImageFromCurrentImageContext (); 16 17 // 4. end Context 18 UIGraphicsEndImageContext (); 19 20 // Store Image 21 NSData * data = UIImagePNGRepresentation (screenImage); 22 NSString * path = [[terminate (NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent: @ "screenShot.png"]; 23 NSLog (@ "% @", path); 24 [data writeToFile: path atomically: YES] ;}); 25 26}1-(void) viewDidLoad {2 [super viewDidLoad]; 3 // Do any additional setup after loading the view, typically from a nib. 4 5 // enable image context 6 CGFloat rowW = self. view. frame. size. width; 7 CGFloat rowH = 30; 8 uigraphicsbeginimagecontextwittions (CGSizeMake (rowW, rowH), NO, 0.0); 9 10 CGContextRef ctx = UIGraphicsGetCurrentContext (); 11 // Color Block Background 12 [[UIColor redColor] set]; 13 CGContextAddRect (ctx, CGRectMake (0, 0, rowW, rowH); 14 CGContextFillPath (ctx ); 15 16 // draw line 17 [[UIColor greenColor] set]; 18 CGFloat lineWidth = 2; 19 CGContextSetLineWidth (ctx, lineWidth); 20 CGFloat lineX = 0; 21 CGFloat lineY = rowH-lineWidth; 22 CGContextMoveToPoint (ctx, lineX, lineY); 23 CGContextAddLineToPoint (ctx, rowW-lineX, lineY); 24 CGContextStrokePath (ctx ); 25 26 UIImage * image = UIGraphicsGetImageFromCurrentImageContext (); 27 28 // fill the screen in Tiled mode 29 [self. view setBackgroundColor: [UIColor colorWithPatternImage: image]; 30 31 UIGraphicsEndImageContext (); 32}