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https://github.com/wilddylan/drawboarddemo

DrawBoardDemo
https://github.com/wilddylan/drawboarddemo

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DrawBoardDemo

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README

          

# DrawBoardDemo

UIBezierPath 简介:

使用`UIBezierPath`类可以创建基于矢量的路径。此类是`Core Graphics`框架关于path的一个封装。使用此类可以定义简单的形状,如椭圆或者矩形,或者有多个直线和曲线段组成的形状。

1.Bezier Path 基础
`UIBezierPath`对象是CGPathRef数据类型的封装。path如果是基于矢量形状的,都用直线和曲线段去创建。我们使用直线段去创建矩形和多边形,使用曲线段去创建弧(arc),圆或者其他复杂的曲线形状。每一段都包括一个或者多个点,绘图命令定义如何去诠释这些点。每一个直线段或者曲线段的结束的地方是下一个的开始的地方。每一个连接的直线或者曲线段的集合成为subpath。一个`UIBezierPath`对象定义一个完整的路径包括一个或者多个subpaths。

创建和使用一个path对象的过程是分开的。创建path是第一步,包含一下步骤:
- 创建一个path对象。
- 使用方法`moveToPoint:`去设置初始线段的起点。
- 添加line或者curve去定义一个或者多个subpaths。
- 改变`UIBezierPath`对象跟绘图相关的属性。例如,我们可以设置`stroked path`的属性`lineWidth`和`lineJoinStyle`。也可以设置filled path的属性`usesEvenOddFillRule`。

当创建path,我们应该管理path上面的点相对于原点(0,0),这样我们在随后就可以很容易的移动path了。为了绘制path对象,我们要用到stroke和fill方法。这些方法在`current graphic context`下渲染path的line和curve段。

2.在path下面添加线或者多边形。
线和多边形是一些简单的形状,我们可以用`moveToPoint:`或者`addLineToPoint:`方法去构建。方法`moveToPoint:`设置我们想要创建形状的起点。从这点开始,我们可以用方法`addLineToPoint:`去创建一个形状的线段。我们可以连续的创建line,每一个line的起点都是先前的终点,终点就是指定的点。

逻辑构造:
DLPaintView: 画板
DLDrawShape: 工具

我这里只实现了3中工具 矩形 椭圆 线 线宽 颜色, 还有很多的工具大家可以自己加了试一下。 按照官方的注释。

```objc
```

DLPaint.h

```objc
#import "DLDarwShape.h"

//! @abstract DLPaint View
@interface DLPaintView : UIView

//! @abstract Shape Array With Shape objects

/*!
* Add New Shape Object When Touch begin, Change ShapeObject.bezierPath.
*/
@property (nonatomic, strong) NSMutableArray *allShape;

//! @abstract Darw Shape type
@property (nonatomic, assign) DLPaintShapeType dType;

//! @abstract Darw Line Width
@property (nonatomic, assign) CGFloat lineWidth;

//! @abstract Draw Linw Color
@property (nonatomic, strong) UIColor * drawColor;

/*!
* un do last step
*/
- (void)backout;

/*!
* clean white board
*/
- (void)cleanBoard;

@end

```

DLPaintView.m

```objc
#import "DLPaintView.h"
#import "DLDarwShape.h"

@implementation DLPaintView

- (instancetype)initWithFrame:(CGRect)frame {

self = [super initWithFrame:frame];
if (self) {

[self DefaultInit];
}
return self;
}

- (void)awakeFromNib {

[self DefaultInit];
}

- (void)DefaultInit {

_dType = DLPAINT_LINE;
_lineWidth = 2;
_drawColor = [UIColor blackColor];
}

// - //

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {

CGPoint startPoint = [[touches anyObject] locationInView:self];
DLDarwShape * shape = [[DLDarwShape alloc] initWithStartPoint:startPoint paintType:_dType color:_drawColor lineWidth:_lineWidth];

[_allShape addObject:shape];
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {

CGPoint currentPoint = [[touches anyObject] locationInView:self];
[DLDrawPointHandle OperateShapeAction:_allShape.lastObject currentPoint:currentPoint];

[self setNeedsDisplay];
}

// - //

- (void)drawRect:(CGRect)rect {

[self.allShape enumerateObjectsUsingBlock:^(DLDarwShape * ShapeObject, NSUInteger idx, BOOL *stop) {

[ShapeObject Draw];
}];
}

- (void)backout {

[self.allShape removeLastObject];
[self setNeedsDisplay];
}

- (void)cleanBoard {

[self.allShape removeAllObjects];
[self setNeedsDisplay];
}

- (NSMutableArray *)allShape {

if (!_allShape) {

_allShape = [NSMutableArray array];
}

return _allShape;
}

@end

```

DLDrawShape:

.h

```objc
#import
#import

typedef NS_OPTIONS(NSUInteger, DLPaintShapeType){

DLPAINT_LINE = 1UL << 0,
DLPAINT_RECT = 1UL << 1,
DLPAINT_OVAL = 1UL << 2
};

//! @abstract Shape Base Object
@interface DLDarwShape : NSObject

//! @abstract stroke Color for shape obejct
@property (nonatomic, strong) UIColor *strokeColor;

//! @abstract Stroke width for shape object
@property (nonatomic, assign) CGFloat strokewidth;

//! @abstract Shape Start point
@property (nonatomic, assign) CGPoint startPoint;

//! @abstract The bezier
@property (nonatomic, retain) UIBezierPath *bezierPath;

//! @abstract Type
@property (nonatomic, assign) DLPaintShapeType paintType;

//! @abstract path array
@property (nonatomic, strong) NSMutableArray * pathArray;

/*!
* Load Shape With start point and type
*
* @param start touch begin Point
* @param pType shape type
* @param color shape object . bezierPath strokeColor
* @param lineWidth shape object . bezierPath strokewidth
*
* @return instance for shape object
*/
- (instancetype)initWithStartPoint: (CGPoint)start
paintType: (DLPaintShapeType)pType
color: (UIColor *)color
lineWidth: (CGFloat)strokeWidth;
/*!
* Draw
*/
- (void)Draw;

@end

@interface DLDrawPointHandle : NSObject

/*!
* Handle Shape Object Action
*
* @param shape Shape Object
* @param cuPoint current point, When Touch moved
*/
+ (void)OperateShapeAction: (DLDarwShape *)shape currentPoint: (CGPoint)cuPoint;

@end

```

.m

```objc
#import "DLDarwShape.h"

@implementation DLDarwShape

- (instancetype)initWithStartPoint: (CGPoint)start
paintType: (DLPaintShapeType)pType
color: (UIColor *)color
lineWidth: (CGFloat)strokeWidth {


self = [super init];
if (self) {

_startPoint = start;
_paintType = pType;

_strokeColor = color;
_strokewidth = strokeWidth;

_bezierPath = [UIBezierPath bezierPath];

[_bezierPath setLineJoinStyle:kCGLineJoinRound];
[_bezierPath setLineCapStyle:kCGLineCapRound];
[_bezierPath moveToPoint:_startPoint];
}
return self;
}

- (NSMutableArray *)pathArray {

if (!_pathArray) {
_pathArray = [NSMutableArray array];
}
return _pathArray;
}

- (void)Draw {

[_strokeColor setStroke];
_bezierPath.lineWidth = _strokewidth;
[_bezierPath stroke];
}

@end

@implementation DLDrawPointHandle

+ (void)OperateShapeAction:(DLDarwShape *)shape currentPoint:(CGPoint)cuPoint {

switch (shape.paintType) {
case DLPAINT_LINE:

[shape.bezierPath addLineToPoint:cuPoint];
break;
case DLPAINT_OVAL:

shape.bezierPath = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(shape.startPoint.x, shape.startPoint.y, cuPoint.x - shape.startPoint.x, cuPoint.y - shape.startPoint.y)];
break;

case DLPAINT_RECT:

shape.bezierPath = [UIBezierPath bezierPathWithRect:CGRectMake(shape.startPoint.x, shape.startPoint.y, cuPoint.x - shape.startPoint.x, cuPoint.y - shape.startPoint.y)];
break;

default:
break;
}

[shape.pathArray addObject:[NSValue valueWithCGPoint:cuPoint]];
}

@end

```

效果:

![屏幕快照 2015-06-18 下午2.09.31.png](http://upload-images.jianshu.io/upload_images/144590-e7601b323adfb212.png)

copyRight@Wild Dylan. 2015-6-18