使用ImageIO.write的质量损失
问题描述：
我已经注意到使用ImageIO.write显着的质量损失，如何禁用自动压缩？
I have noticied significant quality loss using ImageIO.write, how I can disable automatic compression ?
val baos: ByteArrayOutputStream = new ByteArrayOutputStream
val newBi = new BufferedImage(img.getWidth, img.getHeight, BufferedImage.TYPE_INT_RGB)
val gr = newBi.createGraphics()
gr.drawImage(img, 0, 0, img.getWidth(), img.getHeight(), Color.WHITE, null)
ImageIO.write(newBi, "jpeg", baos)
val b = baos.toByteArray
baos.close()
答
使用 ImageWriter 。
ImageWriter writer = ImageIO.getImageWritersByFormatName("jpeg").next();
ImageWriteParam param = writer.getDefaultWriteParam();
param.setCompressionMode(ImageWriteParam.MODE_EXPLICIT); // Needed see javadoc
param.setCompressionQuality(1.0F); // Highest quality
writer.write(image);
对于非照片图像，请使用.png。
For non-photo images use .png.
正如@PiotrekDe评论的那样，以下似乎更符合逻辑。
As @PiotrekDe commented, the following seems more logical.
writer.write(null, new IIOImage(image, null, null), param)