如何使用 Quartz2D 绘制可动画的标尺？

发布于 2024-08-27 05:44:47 字数 95 浏览 8 评论 0原文

我想用 Quartz2D 画一把简单的尺子的线条，仅供练习。

由于我不知道如何在 iPhone 上以编程方式制作矢量图形，也许有人可以给我指点一个好的入门教程？

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深爱不及久伴 2024-09-03 05:44:47

正如 Plamen 指出的，Quartz 2D 文档< /a> 值得一读。此外，课程笔记可在线获取（VoodooPad 格式），供我使用iPhone 开发课程，我用整个课程来学习 Quartz 2D 绘图。我创建的 QuartzExamples 示例应用程序显示了一些更高级的绘图概念，但是Apple 的 QuartzDemo 示例是一个更好的起点看看如何做简单的绘图。

作为为标尺绘制刻度的示例，以下是我用来执行类似操作的代码：

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

CGContextSetStrokeColorWithColor(context, [MyView blackColor]);

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) + 0.5, round(currentTickNumber * minorTickSpacingInPixels) + 0.5);
        minorTickCounter = 0;               
    }
    else
    {
        CGContextAddLineToPoint(context, round(leftEdgeForTicks + minorTickLength) + 0.5, round(currentTickNumber * minorTickSpacingInPixels) + 0.5);
    }
}

CGContextStrokePath(context);

其中 currentHeight 是要覆盖的区域的高度，[MyView blackColor]< /code> 只是返回一个表示黑色的 CGColorRef。

As Plamen points out, the Quartz 2D documentation is worth reading. Additionally, the course notes are available online (VoodooPad format) for my iPhone development course, where I devote an entire class to Quartz 2D drawing. The QuartzExamples sample application I created shows some more advanced drawing concepts, but Apple's QuartzDemo sample is a better place to start to see how you can do simple drawing.

As an example of drawing ticks for a ruler, the following is code that I have used to do something similar:

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

CGContextSetStrokeColorWithColor(context, [MyView blackColor]);

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) + 0.5, round(currentTickNumber * minorTickSpacingInPixels) + 0.5);
        minorTickCounter = 0;               
    }
    else
    {
        CGContextAddLineToPoint(context, round(leftEdgeForTicks + minorTickLength) + 0.5, round(currentTickNumber * minorTickSpacingInPixels) + 0.5);
    }
}

CGContextStrokePath(context);

where currentHeight is the height of the area to cover, and [MyView blackColor] simply returns a CGColorRef representing the color black.

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