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Quartz 2D 是Core Graphics中的2D 绘制呈现引擎。Quartz
中使用的图形环境也由一个类CGContext表示。在Quartz 中可以把一个图形环境作为一个绘制目标。当使用Quartz 进行绘制时，所有设备特定的特性被包含在你使用的特定类型的图形环境中，因此通过给相同的图像操作函数提供不同的图像环境你就能够画相同的图像到不同的设备上，因此做到了图像绘制的设备无关性。
项目需要绘制折线图,需要实时更新折线图,网上看了一些
demo 似乎并不适合,不了解以为很复杂,实际上一般的需求并没有想象的复杂.废话不说,直接上代码.
1
. 定义绘制视图 .h 文件
#import <UIKit/UIKit.h>
@interface YLIneView : UIView
/**
@brief x
轴上的值
*/
@property(nonatomic,strong)NSArray*
xValues;
/**
@brief y
轴上的值
*/
@property(nonatomic,strong)NSArray*
yValues;
/**
@brief x
轴的刻度值
*/
@property(nonatomic,strong)NSArray*
xKeDuValus;
/**
@brief y
轴的刻度值
*/
@property(nonatomic,strong)NSArray*
yKeDuValus;
/**
@brief x
轴上文字颜色
*/
@property(nonatomic,strong)UIColor*
xValueColor;
/**
@brief y
轴上文字颜色
*/
@property(nonatomic,strong)UIColor*
yValueColor;
@end
.m 文件
#import "YLIneView.h"
#import "UIView+Extension.h"
#define kStartX 20.0
#define kBottomHeight 30.0
// x 轴距离底部高度
#define kTopMargin 80.0
// y 轴距离顶部的高度
#define kLabelHeight 44.0
@interface YLIneView()
@property(nonatomic,assign)CGPoint
perviousPoint;
@end
@implementation YLIneView
-(instancetype)initWithFrame:(CGRect)frame
{
if (self = [super
initWithFrame:frame]) {
self.backgroundColor=[UIColor
whiteColor];
// 顶部 label
UILabel* textLabel=[[UILabel
alloc] initWithFrame:CGRectMake(0,
0, self.bounds.size.width,
44.0)];
textLabel.text=@"充电中";
textLabel.textAlignment=NSTextAlignmentCenter;
[self
addSubview:textLabel];
// 做端文字 label
UILabel* titleLabel=[[UILabel
alloc] init];
titleLabel.text=@"(度数)";
titleLabel.font=[UIFont
systemFontOfSize:12];
[titleLabel sizeToFit];
titleLabel.yl_y=textLabel.yl_bottom;
[self
addSubview:titleLabel];
}
return
self;
}
-(void)setXValues:(NSArray *)xValues
{
_xValues=xValues;
[self
setNeedsDisplay];
}
-(void)setYValues:(NSArray *)yValues
{
_yValues=yValues;
[self setNeedsDisplay];
}
-(void)drawRect:(CGRect)rect
{
// 间距
CGFloat x_space=(rect.size.width - 10 -
5 - 20) /
self.xKeDuValus.count;
CGFloat y_space=(rect.size.height - kBottomHeight - kTopMargin -
20) / self.yKeDuValus.count;
CGContextRef ctx = UIGraphicsGetCurrentContext();
// 画 x
轴
UIBezierPath* path = [UIBezierPath bezierPath];
CGPoint startA=CGPointMake(0, rect.size.height - kBottomHeight);
CGPoint endA=CGPointMake(rect.size.width - 5, rect.size.height - kBottomHeight);
[path moveToPoint:startA];
[path addLineToPoint:endA];
CGContextAddPath(ctx, path.CGPath);
[[UIColor lightGrayColor] set];
CGContextSetLineWidth(ctx, 1);
// 渲染
CGContextStrokePath(ctx);
// 绘制右侧箭头图片
UIImage *xImg=[UIImage imageNamed:@"right"];
[xImg drawInRect:CGRectMake(rect.size.width-5 -
5, rect.size.height -
35, 8,
10)];
/** 画 y
轴 */
UIBezierPath* yPath=[UIBezierPath bezierPath];
CGPoint yStart=CGPointMake(kStartX, rect.size.height - kBottomHeight);
CGPoint yEnd=CGPointMake(kStartX, kTopMargin);
[yPath moveToPoint:yStart];
[yPath addLineToPoint:yEnd];
CGContextAddPath(ctx, yPath.CGPath);
CGContextStrokePath(ctx);
UIImage *yImg=[UIImage imageNamed:@"up"];
[yImg drawInRect:CGRectMake(kStartX - 4, kTopMargin,
8, 10)];
/** 画 y
轴坐标横线*/
for (int i =
0; i < self.yKeDuValus.count; i++) {
[[UIColor lightGrayColor] setStroke];
CGContextSetLineWidth(ctx, 1);
CGContextBeginPath(ctx);
CGContextMoveToPoint(ctx,kStartX - 4 , rect.size.height - kBottomHeight - y_space * (i+1));
CGContextAddLineToPoint(ctx,kStartX,rect.size.height - kBottomHeight - y_space * (i+1));
CGContextDrawPath(ctx, kCGPathStroke);
// 画数字
NSString* yStr=[NSString stringWithFormat:@"%@",self.yKeDuValus[i]];
CGSize size=[yStr sizeWithAttributes:@{NSFontAttributeName : [UIFont systemFontOfSize:12]}];
[yStr drawInRect:CGRectMake(0, rect.size.height -
40 - y_space * (i +
1) , kBottomHeight, size.height) withAttributes:@{NSForegroundColorAttributeName :
self.yValueColor}];
}
UIBezierPath* path1=[UIBezierPath bezierPath];
endA=CGPointMake([self.xValues[0] intValue], [self.yValues[0]
intValue]);
startA=CGPointMake(kStartX, rect.size.height - kBottomHeight);
[path1 moveToPoint:startA];
/** 计算移到 y
轴的位置*/
for (int i =
0; i < self.xValues.count; i++) {
CGFloat X =kStartX + x_space * (i+1) ;//[xValue[i] intValue]; //, [yValue[1] intValue])
CGFloat Y =rect.size.height - kBottomHeight - y_space * [self.yValues[i] intValue] *
0.1;
[path1 addLineToPoint:CGPointMake(X, Y)];
}
CGContextAddPath(ctx, path1.CGPath);
CGContextSetLineWidth(ctx, 6);
CGContextSetRGBStrokeColor(ctx, 131.0/255.0,
190.0/255.0,
34.0/255.0,
1.0);
CGContextStrokePath(ctx);
// 填充色
UIBezierPath* path2=[UIBezierPath bezierPath];
endA=CGPointMake(x_space * 0, [self.yValues[0] intValue]);
[path2 moveToPoint:startA];
for (int i =
0; i < self.xValues.count; i++) {
CGFloat X =kStartX + x_space * (i+1) ;
CGFloat Y = rect.size.height - kBottomHeight - y_space * [self.yValues[i] intValue] *
0.1;
[path2 addLineToPoint:CGPointMake(X, Y)];
if (i ==
self.xValues.count -
1) {
[path2 addLineToPoint:CGPointMake(kStartX + x_space * (i +
1), rect.size.height - kBottomHeight)];
}
}
CGContextAddPath(ctx, path2.CGPath);
CGContextSetRGBFillColor(ctx,215.0/255.0,
236.0/255.0,
177.0/255.0,
1.0);
CGContextFillPath(ctx);
// 绘制矩形框
NSString* text=[NSString stringWithFormat:@"%.1f",[self.yValues.lastObject floatValue]]; CGSize textSize=[text sizeWithAttributes:@{NSFontAttributeName:[UIFont
systemFontOfSize:11.0]}];
CGRect texRrect=CGRectMake(kStartX + x_space * self.xValues.count, rect.size.height - kBottomHeight - y_space * [self.yValues.lastObject
intValue] * 0.1 -
20, textSize.width, textSize.height);
CGRect juRect=CGRectMake(kStartX + x_space * self.xValues.count-
5, rect.size.height - kBottomHeight - y_space * [self.yValues.lastObject intValue] *
0.1 - 20, textSize.width+10, textSize.height);
UIBezierPath* path3=[UIBezierPath bezierPathWithRoundedRect:juRect cornerRadius:5];
CGContextAddPath(ctx, path3.CGPath);
CGContextSetRGBFillColor(ctx, 131.0/255.0,
190.0/255.0,
34.0/255.0,
1.0);
CGContextFillPath(ctx);
[text drawInRect:texRrect withAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:11.0],NSForegroundColorAttributeName:[UIColor
whiteColor]}];
// 绘制底部的分割度线
for (int i =
0; i < self.xKeDuValus.count; i++) {
[[UIColor lightGrayColor] setStroke];
CGContextSetLineWidth(ctx, 1);
CGContextBeginPath(ctx);
CGContextMoveToPoint(ctx,kStartX + x_space * i , rect.size.height - kBottomHeight);
CGContextAddLineToPoint(ctx,kStartX + x_space * i, rect.size.height -
25);
CGContextDrawPath(ctx, kCGPathStroke);
NSString *x_titleStr= [NSString stringWithFormat:@"%@",self.xKeDuValus[i] ];
CGSize titleSize=[x_titleStr sizeWithAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:12.0]}];
[x_titleStr drawInRect:CGRectMake(kStartX + x_space * i - titleSize.width*0.5, rect.size.height -
25, titleSize.width, titleSize.height) withAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:12.0],NSForegroundColorAttributeName:[UIColor
lightGrayColor]}];
if (i ==
self.xKeDuValus.count -
1) {
NSString *textStr=@"时间/小时";
CGSize titleSize=[textStr sizeWithAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:11.0]}];
[textStr drawInRect:CGRectMake(10 + x_space * i - titleSize.width*0.5, rect.size.height -
12, titleSize.width, titleSize.height) withAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:11.0],NSForegroundColorAttributeName:self.xValueColor}];
}
}
}
@end
2 控制器中的实现 .m 文件
#import "ViewController.h"
#import "YLIneView.h"
@interface
ViewController ()
@property(nonatomic,weak)YLIneView*
LineView;
@end
@implementation ViewController
- (void)viewDidLoad {
[super
viewDidLoad];
YLIneView* LineView=[[YLIneView
alloc] initWithFrame:CGRectMake(0,
100,[UIScreen
mainScreen].bounds.size.width,
300)];
LineView.xValues=@[@20,@50,@80,];
LineView.yValues=@[@10,@26,@35];
LineView.xKeDuValus=@[@0,@2,@4,@6,@8,@10,@12,@14,@16];
LineView.yKeDuValus=@[@10,@20,@35,@40,@50,@60,@70,@80,@90,@100];
LineView.yValueColor=[UIColor
redColor];
LineView.xValueColor=[UIColor
lightGrayColor];
[self.view
addSubview:LineView];
self.LineView=LineView;
[self
performSelector:@selector(changeValue)
withObject:nil
afterDelay:5.0];
}
-(void)changeValue
{
self.LineView.xValues=@[@20,@50,@80,@110,@210,@250,@270];
self.LineView.yValues=@[@10,@26,@35,@50,@90,@30,@70];
}
@end
cocochina demo 地址:
/********************************************************************* 效果图 *********************************************************************/
  
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