在目标c iPhone中绘制标尺

Question

我正在尝试使用Brad Larson的this post代码创建动态标尺

NSInteger majorTickInterval = 5;
    NSInteger totalTravelRangeInMicrons = 1000;
    NSInteger minorTickSpacingInMicrons = 50;
    CGFloat currentHeight = 100;
    int leftEdgeForTicks = 10;
    int majorTickLength = 15;
    int minorTickLength = 10;

    NSInteger minorTickCounter = majorTickInterval;
    NSInteger totalNumberOfTicks = totalTravelRangeInMicrons / minorTickSpacingInMicrons;
    CGFloat minorTickSpacingInPixels = currentHeight / (CGFloat)totalNumberOfTicks;

    CGContextSetStrokeColorWithColor(context, [[UIColor blackColor] CGColor]);

    for (NSInteger currentTickNumber = 0; currentTickNumber < totalNumberOfTicks; currentTickNumber++)
    {
        CGContextMoveToPoint(context, leftEdgeForTicks + 0.5, round(currentTickNumber * minorTickSpacingInPixels) + 0.5);

        minorTickCounter++;
        if (minorTickCounter >= majorTickInterval)
        {
            CGContextAddLineToPoint(context, round(leftEdgeForTicks + majorTickLength) + 7**.5, round(currentTickNumber * minorTickSpacingInPixels) + 0.5);
            minorTickCounter = 0;               
        }
        else
        {
            CGContextAddLineToPoint(context, round(leftEdgeForTicks + minorTickLength) + 0.5, round(currentTickNumber * minorTickSpacingInPixels) + 0.5);
        }

    }

    CGContextStrokePath(context);

但问题是它正在垂直创建刻度而不是水平，如下面的屏幕截图所示：

虽然我想画一个这样的尺子：

它也没有给我超过25个刻度，我玩过代码但仍然不成功。

任何指导如何解决此问题。

Answer 1

这是一个实现，从头到尾...我认为保持可读非常重要。

CGFloat leftMargin= 10;
CGFloat topMargin = 10;
CGFloat height = 30;
CGFloat width = 200;
CGFloat minorTickSpace = 10;
int multiple = 5;              // number of minor ticks per major tick
CGFloat majorTickLength = 20;  // must be smaller or equal height, 
CGFloat minorTickLength = 10;  // must be smaller than majorTickLength

CGFloat baseY = topMargin + height;
CGFloat minorY = baseY - minorTickLength;
CGFloat majorY = baseY - majorTickLength;
CGFloat majorTickSpace = minorTickSpace * multiple;

int step = 0;
for (CGFloat x = leftMargin; x <= leftMargin + width, x += minorTickLength) {
   CGContextMoveToPoint(context, x, baseY);
   CGFloat endY = (step*multiple*minorTickLength  == x) ? majorY : minorY;
   CGContextAddLineToPoint(context, x, endY);
   step++;  // step contains the minorTickCount in case you want to draw labels
}
CGContextStrokePath(context);