柱形图

NTChartView.h:

@interface NTChartView : UIView {
    
    //组数据，只实现一个组
    NSArray *groupData;
    
    //最大值，最小值, 列宽度,
    float maxValue,minValue,columnWidth,sideWidth,maxScaleValue,maxScaleHeight;
    
    
}

@property(retain,nonatomic) NSArray *groupData;
@end

NTChartView.m:

#import "NTChartView.h"

static int MARGIN_LEFT = 50;
static int MARGIN_BOTTOM = 30;
static int MARGIN_TOP = 20;
static int SHOW_SCALE_NUM = 5;


@interface NTChartView(private)
-(void)drawColumn:(CGContextRef)context rect:(CGRect)_rect;
-(void)drawScale:(CGContextRef)context rect:(CGRect)_rect;
-(void)calcScales:(CGRect)_rect;
@end

@implementation NTChartView
@synthesize groupData;


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


-(void)drawRect:(CGRect)_rect{
    
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetFillColorWithColor(context, [UIColor whiteColor].CGColor);
    CGContextFillRect(context, _rect);
    
    //计算刻度
    [self calcScales:_rect];
    
    //画刻度
    [self drawScale:context rect:_rect];
    
    //画柱
    [self drawColumn:context rect:_rect];
        
}

-(void)drawScale:(CGContextRef)context rect:(CGRect)_rect{
    CGPoint points[3];
    points[0] = CGPointMake(MARGIN_LEFT - 10, MARGIN_TOP);
    points[1] = CGPointMake(MARGIN_LEFT -10, _rect.size.height - MARGIN_BOTTOM + 1);
    points[2] = CGPointMake(_rect.size.width - 10, _rect.size.height - MARGIN_BOTTOM + 1);
    CGContextSetAllowsAntialiasing(context, NO);
    CGContextAddLines(context, points, 3);
    
    
    CGContextSetFillColorWithColor(context, [UIColor blackColor].CGColor);
    
    for(int i=0;i<SHOW_SCALE_NUM + 1; i++){
        maxScaleHeight = (_rect.size.height - MARGIN_BOTTOM) * ( i ) / (SHOW_SCALE_NUM + 1);
        int vScal = ceil(1.0 * maxScaleValue / (SHOW_SCALE_NUM ) * (i ));
        float y = (_rect.size.height - MARGIN_BOTTOM) -
            maxScaleHeight;
        
        NSString *scaleStr = [NSString stringWithFormat:@"%d",vScal];
        [scaleStr
            drawAtPoint:CGPointMake(MARGIN_LEFT - 20 - [scaleStr sizeWithFont:[UIFont systemFontOfSize:12]].width, y - 10) withFont:[UIFont systemFontOfSize:12]];
        points[0] = CGPointMake(MARGIN_LEFT - 10, y);
        points[1] = CGPointMake(MARGIN_LEFT - 13, y);
        CGContextSetLineDash(context, 0, NULL, 0);
        CGContextAddLines(context, points, 2);
        CGContextSetStrokeColorWithColor(context, [UIColor blackColor].CGColor);

        CGContextDrawPath(context, kCGPathStroke);

        
        points[0] = CGPointMake(MARGIN_LEFT - 10, y);
        points[1] = CGPointMake(_rect.size.width - 10 , y);
        float partren[] = {2,3};
        CGContextSetStrokeColorWithColor(context, [UIColor colorWithRed:.7 green:.7 blue:.7 alpha:1].CGColor);

        CGContextSetLineDash(context, 0,partren , 2);
        CGContextAddLines(context, points, 2);
        CGContextDrawPath(context, kCGPathStroke);
        
    }
    
    CGContextSetStrokeColorWithColor(context, [UIColor blackColor].CGColor);

    CGContextDrawPath(context, kCGPathStroke);
    CGContextSetAllowsAntialiasing(context, YES);

    
}

-(void)drawColumn:(CGContextRef)context rect:(CGRect)_rect{
    int gNumber = 0, vNumber = 0;
    int baseGroundY = _rect.size.height - MARGIN_BOTTOM, baseGroundX = MARGIN_LEFT;
    CGPoint points[4];
    
    UIColor *columnColor = [UIColor redColor];
    
    CGContextSetFillColorWithColor(context, columnColor.CGColor);
    CGContextSetStrokeColorWithColor(context, [UIColor redColor].CGColor);
    
    for(NSArray *g in groupData){
        vNumber = 0;
        for(NSNumber *v in g){

            float columnHeight = [v floatValue] / maxScaleValue * maxScaleHeight ;
            
            //画正面
            CGContextSetFillColorWithColor(context, columnColor.CGColor);
            CGContextAddRect(context, CGRectMake(vNumber * 20 + baseGroundX + columnWidth * vNumber
                                                 , baseGroundY - columnHeight
                                                 , columnWidth
                                                 , columnHeight));
            CGContextDrawPath(context, kCGPathFill);
            NSLog(@"columnHeight:%f, (_rect.size.height - MARGIN_TOP - MARGIN_BOTTOM ):%f",columnHeight,(_rect.size.height - MARGIN_TOP - MARGIN_BOTTOM ));

            if(columnHeight < 10){
                vNumber++;
                continue;
            }
            
            //画右侧面
            CGContextSetFillColorWithColor(context, [UIColor colorWithRed:.9 green:0 blue:0 alpha:1].CGColor);
            points[0] = CGPointMake(vNumber * 20 + baseGroundX + columnWidth * vNumber + columnWidth, baseGroundY - columnHeight -10);
            points[1] = CGPointMake(vNumber * 20 + baseGroundX + columnWidth * vNumber + columnWidth + sideWidth, baseGroundY - columnHeight -10 );
            points[2] = CGPointMake(vNumber * 20 + baseGroundX + columnWidth * vNumber + columnWidth + sideWidth, baseGroundY );
            points[3] = CGPointMake(vNumber * 20 + baseGroundX + columnWidth * vNumber + columnWidth, baseGroundY );
            
            CGContextAddLines(context, points, 4);
            CGContextDrawPath(context, kCGPathFill);
            
            //画上面
            CGContextSetFillColorWithColor(context, [UIColor colorWithRed:1 green:.4 blue:.4 alpha:1].CGColor);
            points[0] = CGPointMake(vNumber * 20 + baseGroundX + columnWidth * vNumber , baseGroundY - columnHeight );
            points[1] = CGPointMake(vNumber * 20 + baseGroundX + columnWidth * vNumber + sideWidth, baseGroundY - columnHeight -10 );
            points[2] = CGPointMake(vNumber * 20 + baseGroundX + columnWidth * vNumber + columnWidth + sideWidth , baseGroundY - columnHeight -10 );
            points[3] = CGPointMake(vNumber * 20 + baseGroundX + columnWidth * vNumber + columnWidth, baseGroundY - columnHeight );
            
            CGContextAddLines(context, points, 4);
            CGContextDrawPath(context, kCGPathFill);
            
            
            vNumber++;
        }
        gNumber ++;
    }
    
    
}

-(void)calcScales:(CGRect)_rect{
    int columnCount = 0;
    for(NSArray *g in groupData){
        for(NSNumber *v in g){
            if(maxValue<[v floatValue]) maxValue = [v floatValue];
            if(minValue>[v floatValue]) minValue = [v floatValue];
            columnCount++;
        }
    }
    
    maxScaleValue = ((int)ceil(maxValue) + (SHOW_SCALE_NUM - (int)ceil(maxValue) % SHOW_SCALE_NUM));
    
    columnWidth = (_rect.size.width - MARGIN_LEFT * 2) / (columnCount + 1);
    sideWidth = columnWidth *.2;
    columnWidth *= .8;    
}

@end

调用：

NTChartView *v = [[NTChartView alloc] initWithFrame:CGRectMake(10, 10, 300, 300)];
    
    NSArray *g = [NSArray arrayWithObject:[NSMutableArray arrayWithObjects:
                  [NSNumber numberWithFloat:18],
                  [NSNumber numberWithFloat:30],
                  [NSNumber numberWithFloat:16.5],
                  [NSNumber numberWithFloat:55],
                  [NSNumber numberWithFloat:40],nil]];
    v.groupData = g;
    
    [self.view addSubview:v];
    
    [v release];

运行结果：