IOS 作业项目(4)步步完成 画图 程序(中续)

一,程序布局整理

前言://1,程序启动//2,程序流程框架//3,程序界面一致//4,程序界面功能,

//这里只做页面的固定功能, //在首次创建界面时,我们会指定好固定事件触发前的固定方法 //至于另外程序启动后,运行过程中会添加和减少的事件触发的方法,我们会在另外一个"刷新"方法内实现

在上面7大视图中添加按钮事件,这些事件写在所有外观布局代码的最下边,例如在editScene视图中,我们把所有的事件都写在如下内容处,其余视图中的事件按此方式来写

//------------------------------------------------------------------------------------------

//返回按钮功能

[leftButton addTarget:self action:@selector(editSceneBackMainScene:) forControlEvents:UIControlEventTouchUpInside];

//保存按钮功能

[rightButton addTarget:self action:@selector(editSceneBackMainScene:) forControlEvents:UIControlEventTouchUpInside];

//背景颜色按钮的功能

[backgroundButton addTarget:self action:@selector(editSceneToBgColorScene:) forControlEvents:UIControlEventTouchUpInside];

//画笔颜色按钮的功能

[midButton addTarget:self action:@selector(editSceneToLineColorScene:) forControlEvents:UIControlEventTouchUpInside];

//画笔大小按钮的功能

[lineWidthButton addTarget:self action:@selector(editSceneToLineWidthScene:) forControlEvents:UIControlEventTouchUpInside];

//-----------------------------------------------------------------------------------------------------------------------

二,画图

布局和跳转写好之后,就要完成主要功能,最主要功能是画图,界面三

建立一个画图类,.h文件如下:

@interface TuyaPad : UIView

@property (nonatomic,strong)UIColor * lineColor;

@property (nonatomic,assign)CGFloat lineWidth;

-(UIImage *)getImageFromCurrentContext;

@end

实现内容如下:

#import "TuyaPad.h"

@interface TuyaPath:NSObject

@property (nonatomic,assign)CGMutablePathRef path;

@property (nonatomic,assign)CGColorRef color;

@property (nonatomic,assign)CGFloat width;

@end

@implementation TuyaPath

@end

@interfaceTuyaPad()

//存储路径信息

@property (nonatomic,strong)NSMutableArray* pathlist;

@end

@implementation TuyaPad

{

//触摸路径

CGMutablePathRef touchPath;

//中间变量路径

CGMutablePathRef tempPath;

//三个触摸点

CGPoint startPoint,controlPoint,endPoint;

}

- (id)initWithFrame:(CGRect)frame

{

self = [super initWithFrame:frame];

if (self) {

self.lineColor=[UIColor blackColor];

self.lineWidth=10.f;

self.pathlist=[[NSMutableArray alloc]init];

}

returnself;

}

// Only override drawRect: if you perform custom drawing.

// An empty implementation adversely affects performance during animation.

- (void)drawRect:(CGRect)rect

{

[super drawRect:rect];

//1,获取当前画布

CGContextRef context=UIGraphicsGetCurrentContext();

//2,划线

for (TuyaPath *path in self.pathlist) {

//设置描绘颜色

CGContextSetStrokeColorWithColor(context, path.color);

//设置线条宽度

CGContextSetLineWidth(context, path.width);

//将路径添加到画布上

CGContextAddPath(context, path.path);

//设置线条形状

CGContextSetLineCap(context, kCGLineCapRound);

//开始描绘

CGContextStrokePath(context);

}

}

//触摸开始

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

{

//实例化tuyaPath对象

TuyaPath *itemPath=[[TuyaPath alloc]init];

itemPath.color=self.lineColor.CGColor;

itemPath.width=self.lineWidth;

//实例化触摸路径对象

touchPath=CGPathCreateMutable();

itemPath.path=touchPath;

//将TuyaPath对象添加到路径数组内

[self.pathlist addObject:itemPath];

//获取触摸对象

UITouch *touch=[touches anyObject];

startPoint =[touch previousLocationInView:self];

controlPoint=[touch previousLocationInView:self];

endPoint=[touch locationInView:self];

[self touchesMoved:touches withEvent:event];

}

//触摸移动

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

{

//获取触摸对象

UITouch *touch=[touches anyObject];

startPoint=controlPoint;

controlPoint=[touch previousLocationInView:self];

endPoint=[touch locationInView:self];

CGFloat mid1x=(startPoint.x+controlPoint.x)/2.0;

CGFloat mid1y=(startPoint.y+controlPoint.y)/2.0;

CGFloat mid2x=(controlPoint.x+endPoint.x)/2.0;

CGFloat mid2y=(controlPoint.y+endPoint.y)/2.0;

tempPath=CGPathCreateMutable();

CGPathMoveToPoint(tempPath, NULL, mid1x, mid1y);

CGPathAddQuadCurveToPoint(tempPath, NULL, controlPoint.x, controlPoint.y, mid2x, mid2y);

//将中间变量路径添加到触摸路径内

CGPathAddPath(touchPath, NULL, tempPath);

//获取路径数组内的最后一个元素

TuyaPath *laseItem=[self.pathlist lastObject];

laseItem.path=touchPath;

//根据中间变量路径,计算最小范围

CGRect boundingBox=CGPathGetBoundingBox(tempPath);

boundingBox.origin.x-=self.lineWidth;

boundingBox.origin.y-=self.lineWidth;

boundingBox.size.width+=2*self.lineWidth;

boundingBox.size.height+=2*self.lineWidth;

//[self setNeedsDisplay];

[selfsetNeedsDisplayInRect:boundingBox];//在原画板上画bounding区域的内容

}

//触摸结束

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event

{

//获取触摸路径对象

TuyaPath *lastPath=[self.pathlist lastObject];

//指定触摸路径对象结束时,触摸路径是touchPath

lastPath.path=touchPath;

}

-(UIImage *)getImageFromCurrentContext

{

UIGraphicsBeginImageContext(self.bounds.size);//创建画布用UIGraphicsGetCurrentContext()可以获得

[self.layerrenderInContext:UIGraphicsGetCurrentContext()];//self.layer当前画布上的内容  渲染到图片画布

UIImage *result=  UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

[self.pathlistremoveAllObjects];

[selfsetNeedsDisplay];

return result;

}

@end

主要内容如上,剩下的是细节和部分功能,在下节上主要代码.