iPhone开发之自定义柱状图

//
//  Histogram.h
//  CGraph
//
//  Created by Fox on 12-4-16.
//  Copyright 2012 __MyCompanyName__. All rights reserved.
//
//绘制柱状图

#import <UIKit/UIKit.h>
#define kindex 4

@interface Histogram : UIView {
CGFloat colors[kindex][4];//每一个柱状图的颜色
CGRect  rects[kindex];//每一个柱状图的大小形状
CGContextRef canvas;
CGFloat x;
CGFloat y;
CGFloat w;//柱状图宽
CGFloat h;//柱状图高
CGFloat height[kindex];//每一个柱状图的高度
}
@property (nonatomic, assign) CGContextRef canvas;

//设置柱状图的高度
- (void)initHistogramHeight:(float)height1 height2:(float)height2  height3:(float)height3 height4:(float)height4;

@end

//
//  Histogram.m
//  CGraph
//
//  Created by Fox on 12-4-16.
//  Copyright 2012 __MyCompanyName__. All rights reserved.
//

#import "Histogram.h"

@interface Histogram()

- (void)initHistogramHeight:(float)height1 height2:(float)height2  height3:(float)height3 height4:(float)height4;

@end

@implementation Histogram
@synthesize canvas;

- (id)initWithFrame:(CGRect)frame {

self = [super initWithFrame:frame];
if (self) {
// Initialization code.
}
return self;
}

//设置柱状图的高度
- (void)initHistogramHeight:(float)height1 height2:(float)height2  height3:(float)height3 height4:(float)height4{
height[0] = height1;
height[1] = height2;
height[2] = height3;
height[3] = height4;
}

- (void)drawRect:(CGRect)rect {

int index;
float rgb = 255;
//RGB颜色值为4个组成，前三个分别代表R、G、B对应的值/256,最后一个代表透明度

//设置四个柱状图的颜色
colors[0][0] = 176/rgb;
colors[0][1] = 224/rgb;
colors[0][2] = 230/rgb;
colors[0][3] = 1.0;//透明度

colors[1][0] = 135/rgb;
colors[1][1] = 206/rgb;
colors[1][2] = 235/rgb;
colors[1][3] = 1.0;

colors[2][0] = 245/rgb;
colors[2][1] = 222/rgb;
colors[2][2] = 179/rgb;
colors[2][3] = 1.0;

colors[3][0] = 46/rgb;
colors[3][1] = 139/rgb;
colors[3][2] = 87/rgb;
colors[3][3] = 1.0;

rects[0] = CGRectMake(5, 5,height[0]*200,25);
rects[1] = CGRectMake(5, 55,height[1]*200,25);
rects[2] = CGRectMake(5, 105,height[2]*200,25);
rects[3] = CGRectMake(5, 155,height[3]*200, 25);

self.canvas = UIGraphicsGetCurrentContext();
//	CGContextTranslateCTM(self.canvas, 20, rect.size.height-20);
//	CGContextScaleCTM(self.canvas, 1.0, 1.0); //可以设置相反方向的柱状图

for (index = 0; index<kindex; index++) {
CGContextBeginPath(self.canvas);//初始化绘图

CGContextSetFillColor(self.canvas, colors[index]);//设置柱状图的颜色
CGContextAddRect(self.canvas, rects[index]);//设置柱状图的形状

CGContextClosePath(self.canvas);//结束绘图
CGContextFillPath(self.canvas);
}
}

- (void)dealloc {
[super dealloc];
}

@end

- (void)viewDidLoad
{
[super viewDidLoad];

Histogram *histogram = [[Histogram alloc] initWithFrame:CGRectMake(50, 50, 240, 240)];
histogram.backgroundColor = [UIColor clearColor];
[histogram initHistogramHeight:0.5 height2:0.6 height3:0.7 height4:0.8];
[self.view addSubview:histogram];

}