图像旋转时字符串抗锯齿不起作用

Question

I have some problem with string antialiasing in Java. If I use this code

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

on normal (not rotated string), all is fine. But, when I try use antialiasing on rotated image, where I draw string - this string rendering without antialiasing feature.

This is example of my code, where antialiasing doesn't work:

Graphics2D g = originalImage.createGraphics();

AffineTransform affineTransform2 = new AffineTransform();
affineTransform2.setToIdentity();
affineTransform2.translate(125, 325);
affineTransform2.rotate(Math.toRadians(345));

BufferedImage positionImage = new BufferedImage(100, 40, BufferedImage.TYPE_INT_ARGB);
Graphics2D positionImageG2D = positionImage.createGraphics();
positionImageG2D.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
positionImageG2D.setFont(getFont(30f));
positionImageG2D.drawString("Some Text",100, 40);
positionImageG2D.dispose();

g.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
g.drawImage(positionImage, affineTransform2, null); 

Answer 1

You don't draw text to g (last line), so whatever value you pass to KEY_TEXT_ANTIALIASING won't have any effect.

You are drawing a rotated image with already antialiased text. Try setting KEY_INTERPOLATION to VALUE_INTERPOLATION_BICUBIC or VALUE_INTERPOLATION_BILINEAR , which should effect scaling and rotation of images.

Another thing you could try, is to draw the text (rotated) directly onto g , without the temporary image. Should also work, but you might have to adjust positioning relative to the rotation.