绘制线小于一个像素厚度需要Android 4.2中的反锯齿 [英] Drawing line less than one pixel thick requires anti-aliasing in Android 4.2

问题描述

我想在Android中绘制一条非常细的线（小于一个像素的厚度）。我使用

I'm trying to draw a very thin line (less than one pixel thick) in android. I'm using

Paint blackThin = new Paint();
blackThin.setStrokeWidth(0.1f);
blackThin.setColor(Color.BLACK);

以初始化绘画对象。

这在Android 2.2中工作正常，但是当我在4.2（也是4.1，我认为 - 我测试了一个简单 - 我没有测试任何其他版本，除了2.2,4.1.2和4.2）线路不会出现在我画它们。为了使它们出现在4.2，看起来像我必须设置反锯齿标志为真。 （我试过，线路出现了。）但是我真的不想要，因为它模糊线条等。

This works fine in Android 2.2, but when I try it in 4.2 (also 4.1, I think - I tested that one briefly - I haven't tested any other versions other that 2.2, 4.1.2 and 4.2) the lines won't show up when I draw them. To make them show up in 4.2, it seems like I have to set the anti-aliasing flag to be true. (I tried that, and the lines showed up.) But I really don't want that, because that blurs the lines and such.

这是Android中的一个错误？有没有什么我可以做，以使它工作除了打开反走样？

Is this a bug in Android? Is there something I can do to make it work other than turning on anti-aliasing?

编辑：我也测试了这个与像素大小0.9，问题是相同。

I also tested this with a pixel size of 0.9, and the problem is the same.

感谢您的帮助！

推荐答案

在 width 中画出的线不到抗锯齿的像素。

You can't draw lines less than a pixel in width without anti-aliasing.

反锯齿的全部是计算一个像素的颜色，如果一个元素没有完全填充像素（像一行只有十分之一像素的宽度）。

The whole point of anti-aliasing is to calculate what a pixel's colour would be, if a element doesn't completely fill the pixel (Like a line that's only a tenth of a pixel's width).

可以通过绘制一条较浅的线来稍微模拟它，但是仍然不会接近实际的抗锯齿线。

You could somewhat simulate it by drawing a lighter line, but that still wouldn't come close to a actually anti-aliased line.

看看这个图像，例如：

>

通过改变线条的颜色真的不可能复制抗锯齿的结果。

It's really not possible to replicate the anti-aliased result by changing the line's colour.

我实现了示例中的行宽度> 1个像素，但是相同的原理适用。作为用线填充多少像素的结果来计算像素的暗度。因此，灰色的实线不起作用。

I realise the lines in the example are > 1 pixel in width, but the same principle applies. The "darkness" of a pixel is calculated as a result of how much of the pixel is filled with the line. For that reason, a solid grey line won't work.

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