Java Graphics2D 缩放字体填充背景

Question

我在缩放字体以适应背景宽度时遇到问题。我有一个 1000 高度和 350 宽度的背景，当它比背景大时，我正在尝试缩放字体。 我用不同的字体做了几次测试，结果是一样的，有些字母遗漏或文本末尾有空格。

这是代码：

 import java.awt.Color;
 import java.awt.Font;
 import java.awt.FontMetrics;
 import java.awt.Graphics2D;
 import java.awt.RenderingHints;
 import java.awt.geom.AffineTransform;
 import java.awt.image.BufferedImage;
 import java.io.File;
 import java.io.IOException;
 import javax.imageio.ImageIO;

public class PruebaStackoverflow {

 public static void main(String[] args) {

    String titleText = null;
    Graphics2D g2D = null;
    Font testFont = null;

    File imageGrayBackgroundFile = new File(
            "resources/pruebaAltaResolucionGris.png");
    File destinationImageGray = new File("resources/outputTextGray.png");

    BufferedImage background = readImage(imageGrayBackgroundFile);

    titleText = "Lorem ipsum dolor sit amet asdkf sdm";
    testFont = new Font("Lucida Console", Font.PLAIN, 50);

    g2D = background.createGraphics();
    g2D.setColor(Color.BLACK);
    g2D.setFont(testFont);

    g2D.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING,
            RenderingHints.VALUE_TEXT_ANTIALIAS_ON);

    g2D = scaleFontFromFontMetrics(g2D, background, titleText);

    g2D.drawString(titleText, 0, 150);
    g2D.dispose();

    writeImage(destinationImageGray, background);

}

private static Graphics2D scaleFontFromFontMetrics(Graphics2D g2D,
        BufferedImage backgroundImage, String text) {
    double xScale;
    double yScale;
    double scale;
    Integer backgroundWidth = null;
    Integer backgroundHeight = null;
    Integer textWidth = null;
    Integer textHeigth = null;

    backgroundWidth = backgroundImage.getWidth();
    backgroundHeight = backgroundImage.getHeight();

    Font f = g2D.getFont();
    FontMetrics fm = g2D.getFontMetrics(f);

    textWidth = fm.stringWidth(text);
    textHeigth = fm.getHeight();

    xScale = backgroundWidth / (double) textWidth;
    yScale = backgroundHeight / (double) textHeigth;

    if (xScale > yScale) {
        scale = yScale;
    } else {
        scale = xScale;
    }

    g2D.setFont(f.deriveFont(AffineTransform.getScaleInstance(scale, scale)));

    return g2D;
}

private static BufferedImage readImage(File sourceImage) {
    BufferedImage bufferedImage = null;
    try {
        bufferedImage = ImageIO.read(sourceImage);
    } catch (IOException e1) {
        e1.printStackTrace();
    }
    return bufferedImage;
}

private static void writeImage(File destinationImage,
        BufferedImage bufferedImage) {
    try {
        ImageIO.write(bufferedImage, "png", destinationImage);
    } catch (IOException e) {
        e.printStackTrace();
    }

    System.out.println("Image Saved");
}

}

这是缩放文本“Lorem ipsum dolor sit amet asdkf sdm” 这是用仿射变换缩放的文本。

output image with font scaled and 'm' letter missed

希望你能帮帮我，谢谢

Answer 1

您可以测量字符串的长度并验证它是否适合您的内容。

int lengthInPixel = graphics.getFontMetrics().stringWidth("Lorem ipsum dolor sit amet asdkf sdm")

Answer 2

根据我之前的评论，这是一个使用最接近图像宽度的字体大小的解决方案。文本被绘制到单独的图像，调整大小，然后绘制到最终图像。这一切都在createTextImage() 方法中完成。请注意，我创建了背景图像而不是使用文件。

结果可能不如预期的那样清晰，但您可以尝试不同的算法来调整大小。希望它能给你一个起点。

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;

public class Main {

    public static void main(String[] args) {
        String titleText = "Lorem ipsum dolor sit amet asdkf sdm";
        Font initialFont = new Font("Lucida Console", Font.PLAIN, 50);
        BufferedImage textImg = createTextImage(titleText, 350, 1000, 150,
                initialFont, Color.BLACK, Color.GRAY);
        writeImage(new File("outputTextGray.png"), textImg);
    }

    private static BufferedImage createTextImage(String text, int targetWidth,
            int targetHeight, int textYOffset, Font font, Color textColor, Color bgColor) {

        // The final image
        BufferedImage finalImg = createBackgroundImg(targetWidth, targetHeight, bgColor);
        Graphics2D finalImgG = finalImg.createGraphics();        
        Font closestFont = scaleFont(finalImg, font, text);
        finalImgG.setFont(closestFont);

        // Create new image to fit text
        int textWidth = finalImgG.getFontMetrics().stringWidth(text);
        int textHeight = finalImgG.getFontMetrics().getHeight();
        BufferedImage textImg = createBackgroundImg(textWidth, textHeight * 2, bgColor);

        // Draw text
        Graphics2D textImgG = textImg.createGraphics();
        textImgG.setFont(closestFont);
        textImgG.setColor(textColor);
        textImgG.drawString(text, 0, textHeight);

        // Scale text image
        double scale = getScale(textImg.getWidth(), textImg.getHeight(),
                targetWidth, targetHeight);
        Image resized = textImg.getScaledInstance((int) (textImg.getWidth() * scale),
                (int) (textImg.getHeight() * scale), Image.SCALE_SMOOTH);

        // Draw text image onto final image
        finalImgG.drawImage(resized, 0, textYOffset, null);
        return finalImg;
    }

    private static Font scaleFont(BufferedImage img, Font font, String text) {
        Graphics2D g2D = img.createGraphics();
        g2D.setFont(font);
        double scale = getScale(g2D.getFontMetrics().stringWidth(text), 
                g2D.getFontMetrics().getHeight(), img.getWidth(), 
                img.getHeight());
        return g2D.getFont().deriveFont(AffineTransform.getScaleInstance(scale, scale));
    }

    private static double getScale(int width, int height, int targetWidth, int targetHeight) {
        assert width > 0 && height > 0 : "width and height must be > 0";
        double scaleX = (double) targetWidth / width;
        double scaleY = (double) targetHeight / height;
        return scaleX > scaleY ? scaleY : scaleX;
    }

    private static BufferedImage createBackgroundImg(int width, int height, Color color) {
        BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        for (int x = 0; x < bufferedImage.getWidth(); x++) {
            for (int y = 0; y < bufferedImage.getHeight(); y++) {
                bufferedImage.setRGB(x, y, color.getRGB());
            }
        }
        return bufferedImage;
    }

    private static void writeImage(File destinationImage, 
            BufferedImage bufferedImage) {
        try {
            ImageIO.write(bufferedImage, "png", destinationImage);
        } catch (IOException e) {
            e.printStackTrace();
        }
        System.out.println("Image Saved");
    }
}

Answer 3

为了使游戏屏幕适应特定分辨率，我所做的事情是在测试其最大界限后预先计算比率。像这样（我将实际代码更改为您的情况）：

double calculateScaling( BufferedImage image, String text, Font font ){

    //These are final to avoid accidental mending, since they are 
    //the base for our calculations.
    //Belive me, it took me a while to debug the 
    //scale calculation when I made this for my games :P

    /**
     * imageWidth and imageHeight are the bounds
     */
    final int imageWidth = image.getWidth();
    final int imageHeight = image.getHeight();

    Graphics2D g2 = image.createGraphics();
    FontMetrics fm = g2.getFontMetrics( font );


    /**
     * requestedStringWidthSize e requestedStringHeightSize are the measures needed 
     * to draw the text WITHOUT resizing.
     */
    final int requestedStringWidthSize = fm.stringWidth( text );
    final int requestedStringHeightSize = fm.getHeight();


    double stringHeightSizeToUse = imageHeight;
    double stringWidthSizeToUse;

    double scale = stringHeightSizeToUse/requestedStringHeightSize;
    stringWidthSizeToUse = scale*requestedStringWidthSize;

    /**
     * Checking if fill in height makes the text go out of bound in width,
     * if it does, it rescalates it to size it to maximum width.
     */
    if( imageWidth < ((int)(Math.rint(stringWidthSizeToUse))) ) {
        stringWidthSizeToUse = imageWidth;

        scale = stringWidthSizeToUse/requestedStringWidthSize;
        //stringHeightSizeToUse = scale*requestedStringHeightSize;
    }

    g2.dispose(); //we created this to use fontmetrics, now we don't need it.

    return scale;
}

在我的游戏中，我会将比例存储为 float 而不是 double 以避免在运行时进行大量计算，但对你来说这只是一个简单的缩放，对吧？

您现在要做的就是研究代码并将其实施到您的代码中。

我希望我有所帮助。

祝你有美好的一天。 :)