A positividade do CoreGraphics

CoreGraphics é um framework bem poderoso, porém mal compreendido por todos nós, sempre temos medo dele e acabamos usando alternativas. Vou mostrar como o CoreGraphics pode ser usado de maneira simples com pequenos truques sem utilizar geradores de código.

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1. NSCoder Night [self SP];
2. WHOAMI ? I’m Fernando a.k.a ferbass Senior iOS Developer at Akatus SplashCam iOSDevSpot Twitter @fer_bass ferbass@ferbass.com
3. not in app store yet aiqfome sample app
4. Advantages in CoreGraphics Custom UI with native API No need images to create a custom UI Reduce app size Create a reusable classes for your UI
5. First we need understand views
6. Basics
7. UIView - (void)drawRect:(CGRect)rect { ! }
12. UIView - (void)drawRect:(CGRect)rect { CGContextRef context = UIGraphicsGetCurrentContext(); }
14. UIView - (void)drawRect:(CGRect)rect { CGContextRef context = UIGraphicsGetCurrentContext(); ! CGContextSetStrokeColorWithColor(context, [[UIColor redColor] CGColor]); }
15. UIView - (void)drawRect:(CGRect)rect { CGContextRef context = UIGraphicsGetCurrentContext(); ! CGContextSetStrokeColorWithColor(context, [[UIColor grayColor] CGColor]); ! CGContextMoveToPoint(context, CGRectGetMinX(rect) + 15, CGRectGetMaxY(rect)); CGContextAddLineToPoint(context, CGRectGetMaxX(rect) - 15, CGRectGetMaxY(rect)); ! CGContextStrokePath(context); }
17. easy no?
18. CG_EXTERN void CGContextSetLineDash(CGContextRef c, CGFloat phase, const CGFloat lengths[], size_t count) CG_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0); Create a dash line
19. UIView - (void)drawRect:(CGRect)rect { CGContextRef context = UIGraphicsGetCurrentContext(); ! CGContextSetStrokeColorWithColor(context, [[UIColor grayColor] CGColor]); ! CGFloat dashes[] = {1,1}; CGContextSetLineDash(context, 0.0, dashes, 2); ! CGContextMoveToPoint(context, CGRectGetMinX(rect) + 15, CGRectGetMaxY(rect)); CGContextAddLineToPoint(context, CGRectGetMaxX(rect) - 15, CGRectGetMaxY(rect)); ! CGContextStrokePath(context); }
21. View with dotted border - (void)drawRect:(CGRect)rect { CGContextRef context = UIGraphicsGetCurrentContext(); CGContextSetStrokeColorWithColor(context, [[UIColor grayColor] CGColor]); CGFloat dashes[] = {1,1}; CGContextSetLineDash(context, 0.0, dashes, 2); CGContextSetLineWidth(context, 1.0); CGContextMoveToPoint(context, CGRectGetMinX(rect), CGRectGetMaxY(rect)); CGContextAddLineToPoint(context, CGRectGetMaxX(rect), CGRectGetMaxY(rect)); CGContextAddLineToPoint(context, CGRectGetMaxX(rect), CGRectGetMinY(rect)); CGContextAddLineToPoint(context, CGRectGetMinX(rect), CGRectGetMinY(rect)); CGContextAddLineToPoint(context, CGRectGetMinX(rect), CGRectGetMaxY(rect)); CGContextSetShouldAntialias(context, NO); CGContextStrokePath(context); }
22. ZigZag - (void)drawRect:(CGRect)rect { CGContextRef context = UIGraphicsGetCurrentContext(); CGContextSetStrokeColorWithColor(context, [[UIColor colorWithRed:241.0/255.0 green: 241.0/255.0 blue:238.0/255.0 alpha:1] CGColor]); ! CGContextSetLineWidth(context, 0.6); CGContextMoveToPoint(context, CGRectGetMinX(rect), CGRectGetMaxY(rect) - 5); CGContextSetShouldAntialias(context, YES); ! for (int i = 0; i < 320; i++) { float x = (CGRectGetMinX(rect) + 7) * i; float y = CGRectGetMaxY(rect) - 5; CGContextAddLineToPoint(context, x, y); CGContextAddLineToPoint(context, x + 1, y); ! CGContextAddLineToPoint(context, x + 4, CGRectGetMaxY(rect)); CGContextSetShouldAntialias(context, NO); } ! CGContextStrokePath(context); }
23. Custom text fields - (void)drawRect:(CGRect)rect { CGContextRef context = UIGraphicsGetCurrentContext(); CGContextSetStrokeColorWithColor(context, [[UIColor colorWithRed:0.553 green:0.561 blue 0.565 alpha:1.000] CGColor]); CGFloat dashes[] = {1,1}; CGContextSetLineDash(context, 0.0, dashes, 1); CGContextSetLineWidth(context, 1.0); CGContextMoveToPoint(context, CGRectGetMinX(rect), CGRectGetMaxY(rect)); CGContextAddLineToPoint(context, CGRectGetMaxX(rect), CGRectGetMaxY(rect)); CGContextSetShouldAntialias(context, NO); CGContextStrokePath(context); }
24. Use your imagination
25. Links http://www.raywenderlich.com/tag/core-graphics http://www.amazon.com/dp/0123694736/? tag=stackoverfl08-20 http://google.com :P https://developer.apple.com/library/ios/documentation/ coregraphics/reference/coregraphics_framework/ CoreGraphics_Framework.pdf
26. Obrigado !