300dpi tiff image changed to 96pi jpg but pixel does not chage

[liuyi520123]

Expected behavior

300dpi tiff image when change to jpg keep dpi and pixel

Actual behavior

tiff dpi=300dpi pixel=1181 x 1181
image convert to
jpg dpi=96dpi pixel=1181 x 1181

Steps to reproduce the behavior

BufferedImage tif = ImageIO.read(new File("D:\\868602602.tif")); Thumbnails .of(tif) .outputFormat("jpg") .scale(1f) .outputQuality(1f) .toFile(new File("D:\\868602602.jpg"));

Environment

• OS vendor and version:
  windows 11
• JDK vendor and version:
  1.8.0_40
• Thumbnailator version:
  0.4.19
• Test file:
  2211180344517.zip

[coobird]

Sorry for overlooking this issue.

The dots-per-inch (DPI) information is metadata that's kept in certain file formats to instruct how an image should be printed. It doesn't actually affect the contents of the image file itself (i.e., the pixels.)

As Thumbnailator deals with the dimensions in pixels only, setting the scaling to 1x (i.e. .scale(1f)) will end up with the same number of pixels before and after the transformation. This is intended behavior.