证券交易相关App,里面都有K线图,它是对以往交易价格和成交量的直观展示,对交易者具有十分重要的参考意义.所以,掌握相关折线和文字的绘制,显得很有必要.先看效果:
K线图和成交量
图表分为两部分:
上面是根据后台返回数据,绘制的K线图.下面是成交量.
相关知识点如下:
1中间平均线使用UIBezierPath的setLineDash方法绘制间断线;
2K线图使用UIBezierPath实现,并用CAShapeLayer和CAGradientLayer填充渐变图;
3下面成交量的绘制使用UIBezierPath的bezierPathWithRect方法绘制矩形,然后填充颜色;
4利用String的boundingRectWithSize方法计算高度和宽度后,用drawInRect方法绘制;
需要注意的问题:
1要保证K线图的高度不能超过规定的范围,需要在高度方向流出余量.因此需要计算知道绘制范围数值内的最大值和最小值,根据其差值,计算单位高度所对应的点位和成交量.
2绘制文字位置时,不同位置需要调整间隙;
.m文件代码如下,详细请参考Demo
#import "ZDChartView.h"
//H方向预留高度
#define verticalMarginScale 0.1
@implementation ZDChartView
- (void)drawRect:(CGRect)rect{
[super drawRect:rect];
[self drawBounds:rect];
}
- (void)drawBounds: (CGRect)rect{
//上边框
CGFloat xLength = rect.size.width - self.leftMargin - self.rightMargin;
CGFloat yLength = rect.size.height - self.topMargin - self.bottomMargin - self.volumeTopMargin - self.volumeHeight;
CALayer *kLineLayer = [CALayer layer];
kLineLayer.frame = CGRectMake(self.leftMargin, self.topMargin, xLength, yLength);
kLineLayer.borderWidth = 1;
kLineLayer.borderColor = [UIColor grayColor].CGColor;
[self.layer addSublayer:kLineLayer];
//下边框
CALayer *volumnLayer = [CALayer layer];
volumnLayer.frame = CGRectMake(self.leftMargin, rect.size.height - self.bottomMargin - self.volumeHeight, xLength, self.volumeHeight);
volumnLayer.borderWidth = 1;
volumnLayer.borderColor = [UIColor yellowColor].CGColor;
[self.layer addSublayer:volumnLayer];
//上边框横线
UIBezierPath *path = [UIBezierPath bezierPathWithRect:CGRectMake(self.leftMargin, self.topMargin, xLength, yLength)];
path.lineWidth = 1;
CGFloat verticalH = yLength / self.verticalLineCount;
CGFloat dash[] = {5,5};
for (int i = 0; i < self.verticalLineCount; i++) {
if ( i == 0) {
continue;
}
CGFloat endY = self.topMargin + i * verticalH;
[path removeAllPoints];
[path moveToPoint:CGPointMake(self.leftMargin, endY)];
[path addLineToPoint:CGPointMake(rect.size.width - self.rightMargin, endY)];
if (i == 2) {
//dash:实线,虚线交替的长度数组a
//count:取数组a的有效位数, phase:起始跳过的长度
// [path setLineDash:dash count:2 phase:5];
//count>dash的个数时,有效;
[path setLineDash:dash count:2 phase:0];
}else{
//清除
[path setLineDash:dash count:0 phase:0];
}
[[UIColor greenColor] set];
[path stroke];
}
[path removeAllPoints];
CGFloat bottomCenterY = rect.size.height - self.bottomMargin - self.volumeHeight * 0.5;
[path moveToPoint:CGPointMake(self.leftMargin, bottomCenterY)];
[path addLineToPoint:CGPointMake(rect.size.width - self.rightMargin, bottomCenterY)];
[path setLineDash:dash count:2 phase:0];
[[UIColor greenColor] set];
[path stroke];
//上边框K线
[path removeAllPoints];
//高度
CGFloat maxDif = MAX(fabs([self.chartModel.minValue floatValue] - [self.chartModel.lastCloseValue floatValue]), fabs(([self.chartModel.maxValue floatValue] - [self.chartModel.lastCloseValue floatValue])));
CGFloat unitH = yLength * 0.5 * (1 - verticalMarginScale) / maxDif;
NSMutableArray *tempHeightArray = [NSMutableArray arrayWithCapacity:self.chartModel.values.count];
CGFloat halfChartHeight = yLength * 0.5;
//转换成Y坐标值
[self.chartModel.values enumerateObjectsUsingBlock:^(id _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
CGFloat tempH = ([obj floatValue] - [self.chartModel.lastCloseValue floatValue]) * unitH;
[tempHeightArray addObject: [NSString stringWithFormat:@"%lf", halfChartHeight - tempH + self.topMargin]];
}];
//转换成X坐标值
CGFloat unitX = xLength / [self.chartModel.totalTime integerValue];
NSMutableArray *tempTimeArray = [NSMutableArray arrayWithCapacity:self.chartModel.times.count];
[self.chartModel.times enumerateObjectsUsingBlock:^(id _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
CGFloat tempX = ([obj integerValue] - [self.chartModel.openTime integerValue]) * unitX + self.leftMargin;
[tempTimeArray addObject:[NSString stringWithFormat:@"%lf", tempX]];
}];
//画K线
path.lineWidth = 0.2;
[path moveToPoint:CGPointMake(self.leftMargin, self.topMargin + yLength * 0.5)];
[tempHeightArray enumerateObjectsUsingBlock:^(id _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
[path addLineToPoint:CGPointMake([[tempTimeArray objectAtIndex:idx] floatValue], [obj floatValue])];
}];
[[UIColor blueColor] set];
[path stroke];
//填充颜色
[path addLineToPoint:CGPointMake([tempTimeArray.lastObject floatValue], (self.topMargin + yLength))];
[path addLineToPoint:CGPointMake(self.leftMargin, (self.topMargin + yLength))];
[path closePath];
CAGradientLayer *gradientLayer = [CAGradientLayer layer];
gradientLayer.frame = kLineLayer.frame;
gradientLayer.colors = @[(id)[[UIColor blueColor] colorWithAlphaComponent:0.3].CGColor, (id)[[UIColor whiteColor] colorWithAlphaComponent:0.3].CGColor];
[gradientLayer setStartPoint:CGPointMake(0, 0)];
[gradientLayer setEndPoint:CGPointMake(0, 1)];
//注: 需要调整x和y的坐标
CAShapeLayer *shapeLayer = [CAShapeLayer layer];
shapeLayer.frame = CGRectMake(-self.leftMargin, -self.topMargin, rect.size.width, rect.size.height);
shapeLayer.path = path.CGPath;
gradientLayer.mask = shapeLayer;
[self.layer addSublayer:gradientLayer];
//绘制成交量
CGFloat unitH_volumn = self.volumeHeight / [self.chartModel.maxVolumn floatValue];
[self.chartModel.volumns enumerateObjectsUsingBlock:^(id _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
CGFloat tempX = ([self.chartModel.times[idx] integerValue] - [self.chartModel.openTime integerValue]) * unitX + self.leftMargin;
CGFloat tempH = [self.chartModel.volumns[idx] floatValue] * unitH_volumn;
CGFloat tempW = unitX * 100000;
CGFloat tempY = rect.size.height - self.bottomMargin - tempH;
CGRect tempRect = CGRectMake(tempX - tempW * 0.5, tempY, tempW, tempH);
UIBezierPath *tempPath = [UIBezierPath bezierPathWithRect:tempRect];
UIColor *fillColor;
if ([self.chartModel.volumns[idx] floatValue] > [self.chartModel.current floatValue]) {
fillColor = [UIColor redColor];
}else{
fillColor = [UIColor greenColor];
}
[fillColor set];
[tempPath fill];
}];
//绘制K线左右文字
CGFloat centerPrice = [self.chartModel.lastCloseValue floatValue];
CGFloat maxPrice = centerPrice + unitH * yLength * 0.5;
CGFloat topCenterPrice = centerPrice + unitH * yLength * 0.25;
CGFloat minPrice = centerPrice - unitH * yLength * 0.5;
CGFloat bottomCenterPrice = centerPrice - unitH * yLength * 0.25;
NSArray *leftTextArray = @[[self getString:maxPrice decimalCount:2], [self getString:topCenterPrice decimalCount:2], [self getString:centerPrice decimalCount:2], [self getString:bottomCenterPrice decimalCount:2], [self getString:minPrice decimalCount:2]];
CGFloat unitHMargin = yLength / 4.0;
CGFloat topMargin = 3;
CGFloat leftMargin = 3;
__block CGFloat textH;
CGFloat fontSize = 10;
[leftTextArray enumerateObjectsUsingBlock:^(id _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
NSString *text = (NSString *)obj;
CGFloat textW = 50;
CGRect leftTextRect= [text boundingRectWithSize:CGSizeMake(textW, MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin|NSStringDrawingUsesFontLeading attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:fontSize]} context:nil];
textH = leftTextRect.size.height;
CGFloat offsetY;
NSString *upDownText;
switch (idx) {
case 0:
offsetY = topMargin;
upDownText = [NSString stringWithFormat:@"+%.2f%%", ([text floatValue] - centerPrice) * 100 / centerPrice];
break;
case 1:
upDownText = [NSString stringWithFormat:@"+%.2f%%", ([text floatValue] - centerPrice) * 100 / centerPrice];
offsetY = -textH * 0.5;
break;
case 2:
upDownText = [NSString stringWithFormat:@"0.00%%"];
offsetY = -textH * 0.5;
break;
case 3:
upDownText = [NSString stringWithFormat:@"%.2f%%", ([text floatValue] - centerPrice) * 100 / centerPrice];
offsetY = -textH * 0.5;
break;
default:
upDownText = [NSString stringWithFormat:@"%.2f%%", ([text floatValue] - centerPrice) * 100 / centerPrice];
offsetY = -textH - topMargin;
break;
}
[text drawInRect:CGRectMake(self.leftMargin + leftMargin, self.topMargin + idx * unitHMargin + offsetY, textW, textH) withAttributes: @{NSFontAttributeName:[UIFont systemFontOfSize:fontSize], NSForegroundColorAttributeName: [UIColor grayColor]}];
CGRect upDownRect = [upDownText boundingRectWithSize:CGSizeMake(MAXFLOAT, textH) options:NSStringDrawingUsesFontLeading|NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:fontSize]} context:nil];
[upDownText drawInRect:CGRectMake(rect.size.width - self.rightMargin - upDownRect.size.width - leftMargin, self.topMargin + idx * unitHMargin + offsetY, upDownRect.size.width, textH) withAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:fontSize], NSForegroundColorAttributeName: [UIColor grayColor]}];
}];
//绘制成交量文字
NSString *maxVolume = [NSString stringWithFormat:@"%@", self.chartModel.maxVolumn];
[maxVolume drawInRect:CGRectMake(self.leftMargin + leftMargin, rect.size.height - self.bottomMargin - self.volumeHeight + topMargin, 100, textH) withAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:fontSize], NSForegroundColorAttributeName: [UIColor grayColor]}];
NSString *centerVolume = [NSString stringWithFormat:@"%.0f", [self.chartModel.maxVolumn integerValue] * 0.5];
[centerVolume drawInRect:CGRectMake(self.leftMargin + leftMargin, rect.size.height - self.bottomMargin - self.volumeHeight * 0.5 - textH * 0.5, 100, textH) withAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:fontSize], NSForegroundColorAttributeName: [UIColor grayColor]}];
}
- (NSString *)getString: (CGFloat)value decimalCount: (NSInteger)count{
NSDecimalNumber *number = [NSDecimalNumber decimalNumberWithString:[NSString stringWithFormat:@"%.6f", value]];
NSDecimalNumberHandler *handle = [NSDecimalNumberHandler decimalNumberHandlerWithRoundingMode:NSRoundPlain scale:count raiseOnExactness:NO raiseOnOverflow:NO raiseOnUnderflow:NO raiseOnDivideByZero:NO];
NSString *text = [NSString stringWithFormat:@"%@", [number decimalNumberByRoundingAccordingToBehavior:handle]];
return text;
}
- (void)setChartModel:(ZDChartModel *)chartModel{
_chartModel = chartModel;
[self setNeedsDisplay];
}
@end
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