使用java渲染TrueType字体中突出显示的字符在某些系统上看起来是错误的

2019年7月21日 156次阅读

我有一个问题,将TrueType字体(例如Arial)的字符转换为
java.awt.Shape以进一步手动渲染(作为EPS,但无关紧要).

我已经将执行它的程序分解为小进程以找出问题的来源,并且在我看来问题来自于从字体加载字形的过程.

我使用以下代码片段加载字体(Arial,来自msttcore包)并将字符Ö转换为我稍后可以使用的Shape：

Font font = new Font("Arial", Font.PLAIN, 24);
AttributedString attributedString = new AttributedString("Ö");
attributedString.addAttribute(TextAttribute.FONT, font, 0, "Ö".length());
FontRenderContext fontRenderContext = new FontRenderContext(null, false, false);
TextLayout layout = new TextLayout(attributedString.getIterator(), fontRenderContext);
Shape shape = layout.getOutline(null);

我也尝试使用以下代码片段,但它给了我相同的结果：

Font font = new Font("Arial", Font.PLAIN, 24);
FontRenderContext fontRenderContext = new FontRenderContext(null, false, false);
GlyphVector glyphVector = font.createGlyphVector(fontRenderContext, text);
Shape shape = glyphVector.getOutline();

之后,我使用shape.getPathIterator(null)并迭代它给我打印点坐标的段.我在三个不同的系统上这样做：

> Mac OS X Mountain Lion(10.8)我负责使用Font()构造函数,允许我指向正确的arial.ttf文件,以避免使用系统的内置Arial字体的代码片段.
>基于Fedora的Amazon AWS Linux发行版
>基于Ubuntu服务器的Amazon AWS Linux发行版

在我的Mac上生成java.awt.Shape时,生成的EPS文件看起来正确.在Linux机器上生成java.awt.Shape时,似乎某些点坐标与我在Mac上生成的点坐标不同.

>’Ö’的O部分坐标是不同的,但只是在一个程度上,它只看起来像舍入错误,并且我的眼睛是不可察觉的：
>¨部分看起来非常奇怪,点坐标的差异远大于舍入误差.

见下图：

绿色是从Mac上生成的Shape的路径,红色是类似Fedora的计算机上生成的Shape的路径.

因为两者在O部分上都很好地重叠,所以它看起来有点深绿色.但你可以看到¨部分是非常不同的.它甚至没有以红色路径为中心……

我的实验总结：

> Java版本/发行版不会影响该问题.
>它看起来像所有突出角色的常见问题(到目前为止：ÖÄÅÜ).
>我对Times New Roman字体有同样的问题.

我想我已经尝试了许多没有成功的事情,我不明白为什么会这样,并且会感谢任何提示.

这是我给你的最小的完整代码片段,它显示了问题：

package Experiments;

import java.awt.Font;
import java.awt.Shape;
import java.awt.font.FontRenderContext;
import java.awt.font.GlyphVector;
import java.awt.font.TextAttribute;
import java.awt.font.TextLayout;
import java.awt.geom.PathIterator;
import java.io.File;
import java.text.AttributedString;

public class MyClass
{
    public static void main(String[] args) throws Exception
    {
        Font font = new Font("Arial", Font.PLAIN, 24);
        AttributedString attributedString = new AttributedString("Ö");
        attributedString.addAttribute(TextAttribute.FONT, font, 0, "Ö".length());
        FontRenderContext fontRenderContext = new FontRenderContext(null, false, false);
        TextLayout layout = new TextLayout(attributedString.getIterator(), fontRenderContext);
        Shape shape = layout.getOutline(null);
        PathIterator it = shape.getPathIterator(null);
        double[] points = new double[6];
        double x = 0, y = 0;

        while (!it.isDone())
        {
            double x1 = points[0], y1 = points[1];
            double x2 = points[2], y2 = points[3];
            double x3 = points[4], y3 = points[5];

            switch (it.currentSegment(points))
            {
                case PathIterator.SEG_CLOSE:
                    System.out.println("close");
                    break;
                case PathIterator.SEG_QUADTO:
                    // Convert to cubic curve
                    x3 = x2;
                    y3 = y2;
                    x2 = x1 + 1 / 3f * (x2 - x1);
                    y2 = y1 + 1 / 3f * (y2 - y1);
                    x1 = x + 2 / 3f * (x1 - x);
                    y1 = y + 2 / 3f * (y1 - y);
                case PathIterator.SEG_CUBICTO:
                    System.out.println("curve: " + x1 + "," + y1 + "," + x2 + "," + y2 + "," + x3 + "," + y3);
                    x = x3;
                    y = y3;
                    break;
                case PathIterator.SEG_LINETO:
                    System.out.println("lineto: " + x1 + "," + y1);
                    x = x1;
                    y = y1;
                    break;
                case PathIterator.SEG_MOVETO:
                    System.out.println("moveto: " + x1 + "," + y1);
                    x = x1;
                    y = y1;
                    break;
            }
            it.next();
        }
    }
}

我Mac上的输出是：

moveto: 0.0,0.0
curve: 0.7734375230502337,-5.57812516624108,0.7734374884748831,-5.57812491687946,0.0,0.0
curve: 0.7734375230502337,-8.429687751224265,1.925781272817403,-13.451171899039764,3.45703125,-15.064453125
curve: 4.988281295634806,-16.677734423079528,6.96484378608875,-17.484375,9.38671875,-17.484375
curve: 10.97265629726462,-17.484375,12.402343768975697,-17.105468738707714,13.67578125,-16.34765625
curve: 14.949218787951395,-15.589843727415428,15.91992188495351,-14.533203104801942,16.587890625,-13.177734375
curve: 17.25585939490702,-11.822265584603883,17.58984375,-10.28515622438863,17.58984375,-8.56640625
curve: 17.58984375,-6.8242186980787665,17.23828123952262,-5.265624979510903,16.53515625,-3.890625
curve: 15.832031229045242,-2.5156249590218067,14.835937480791472,-1.4746093644644134,13.546875,-0.767578125
curve: 12.257812461582944,-0.06054685392882675,10.867187477764674,0.29296875,9.375,0.29296875
curve: 7.757812451804057,0.29296875,6.3124999810243025,-0.09765626164153218,5.0390625,-0.87890625
curve: 3.765624962048605,-1.6601562732830644,2.800781240221113,-2.7265625201398507,2.14453125,-4.078125
close
moveto: 1.16015625,-6.10546875
curve: 2.7226562965661287,-7.589843794237822,2.7226562267169356,-8.343750000349246,1.16015625,-8.3671875
curve: 2.7226562965661287,-6.2734374376013875,4.060546891589183,-4.630859357246663,5.173828125,-3.439453125
curve: 6.287109408178367,-2.248046839493327,7.683593775029294,-1.65234375,9.36328125,-1.65234375
curve: 11.074218800989911,-1.65234375,12.482421891472768,-2.2539062679279596,13.587890625,-3.45703125
curve: 14.693359407945536,-4.660156285855919,15.24609375,-6.367187532945536,15.24609375,-8.578125
curve: 15.24609375,-9.976562541676685,15.009765617956873,-11.197265640541445,14.537109375,-12.240234375
curve: 14.064453110913746,-13.283203156082891,13.373046861437615,-14.091796883556526,12.462890625,-14.666015625
curve: 11.55273434787523,-15.240234392113052,10.531249983119778,-15.52734375,9.3984375,-15.52734375
curve: 7.789062452036887,-15.52734375,6.404296857712325,-14.974609358527232,5.244140625,-13.869140625
close
moveto: 3.50390625,-12.2109375
lineto: 6.046875,-18.234375
lineto: 6.046875,-20.63671875
lineto: 8.25,-20.63671875
close
moveto: 8.25,-18.234375
lineto: 10.41796875,-18.234375
lineto: 10.41796875,-20.63671875
lineto: 12.62109375,-20.63671875
close

在类似Fedora的计算机上：

moveto: 0.0,0.0
curve: 0.7708333563059568,-5.583333499729633,0.7708333218470216,-5.583333250135183,0.0,0.0
curve: 0.7708333563059568,-8.427083584479988,1.921875022817403,-13.447916690725833,3.453125,-15.0625
curve: 4.984375045634806,-16.677083381451666,6.963541702833027,-17.484375,9.390625,-17.484375
curve: 10.973958380520344,-17.484375,12.403645852347836,-17.106770822079852,13.6796875,-16.3515625
curve: 14.955729204695672,-15.596354144159704,15.92708334326744,-14.539062479743734,16.59375,-13.1796875
curve: 17.26041668653488,-11.820312459487468,17.59375,-10.28124997438863,17.59375,-8.5625
curve: 17.59375,-6.822916614823043,17.24218748952262,-5.265624979510903,16.5390625,-3.890625
curve: 15.835937479045242,-2.5156249590218067,14.838541647419333,-1.4739583227783442,13.546875,-0.765625
curve: 12.255208294838667,-0.05729164555668831,10.864583311136812,0.296875,9.375,0.296875
curve: 7.760416618548334,0.296875,6.315104147652164,-0.09375001164153218,5.0390625,-0.875
curve: 3.763020795304328,-1.6562500232830644,2.796874990221113,-2.723958353511989,2.140625,-4.078125
close
moveto: 1.15625,-6.109375
curve: 2.7187500465661287,-7.5885417107492685,2.7187499767169356,-8.343750000465661,1.15625,-8.375
curve: 2.7187500465661287,-6.2812499376013875,4.057291683275253,-4.638020815560594,5.171875,-3.4453125
curve: 6.286458366550505,-2.2526041311211884,7.682291691657156,-1.65625,9.359375,-1.65625
curve: 11.078125051222742,-1.65625,12.489583349786699,-2.2578125179279596,13.59375,-3.4609375
curve: 14.697916699573398,-4.664062535855919,15.25,-6.369791699573398,15.25,-8.578125
curve: 15.25,-9.973958374932408,15.013020826270804,-11.195312515599653,14.5390625,-12.2421875
curve: 14.065104152541608,-13.289062531199306,13.372395819751546,-14.098958341870457,12.4609375,-14.671875
curve: 11.549479139503092,-15.244791683740914,10.531249983236194,-15.53125,9.40625,-15.53125
curve: 7.791666618548334,-15.53125,6.4036458160262555,-14.979166650213301,5.2421875,-13.875
close
moveto: 3.5,-12.21875
lineto: 6.625,-18.0
lineto: 6.625,-20.390625
lineto: 8.828125,-20.390625
lineto: 8.828125,-18.0
close
moveto: 6.625,-18.0
lineto: 11.0,-18.0
lineto: 11.0,-20.390625
lineto: 13.203125,-20.390625
lineto: 13.203125,-18.0
close

如果你读到这里,你已经感谢了我:)

最佳答案 你到底为什么要打扰Arial？ “免费”msttcorefonts版本是多年未收到修复的废弃软件.它针对不再存在的字体渲染系统进行了优化(现在众所周知,Microsoft在这些文件中使用了错误的元数据值来解决其当时前沿系统中的错误).

使用用于跨平台使用的现代字体,以及实际允许重新分发和衍生的许可(请参阅DejaVu或Google字体库).你的形状是衍生物.

OSX上的旧java由Apple维护,可能使用Apple特有的字体引擎.
其他系统上的旧Java(与Oracle下载一样)使用专有字体引擎.
OpenJDK使用freetype(甲骨文不敢改变官方的jdk,因为害怕依赖于旧的引擎疣破坏应用程序.遗憾的是,freetype维护得很好).

期望所有人都能得到完全相同的塑形效果,这是徒劳的.而且字体越复杂和越旧,它们就越有可能发散(旧字体包括旧元数据新字体不会,并且取决于字体引擎,它会尝试使用这些旧数据做某事.或者不是.字体格式甚至包括将根据所使用的字体引擎读取或忽略的Apple和Windows特定元数据.

智能字体格式很精彩……

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