如何在使用缩略图调整图像大小时用白色替换黑色背景？

Question

I use Thumbnailator to convert images from png to jpg and then resize them:

Thumbnails.of(new File("C:/279.png"))
                .outputFormat("JPG")
                .size(100, 100)
                .outputQuality(1.0)
                .toFile(new File("C:/279.jpg"));

Original image has transparent background, but output image has black background. How to set white background on output image?

Thank you.

Answer 1

Solution:

Use .addFilter(new Canvas(100, 100, Positions.CENTER, Color.WHITE))

Example:

Thumbnails.of(new File("C:/279.png"))
            .outputFormat("JPG")
            .size(100, 100)
            .addFilter(new Canvas(100, 100, Positions.CENTER, Color.WHITE))
            .outputQuality(1.0)
            .toFile(new File("C:/279.jpg"));