24-bit floating point TIFF doesn't load properly

[jonsneyers]

Description

TIFF files containing 24-bit FP data are loaded incorrectly – it looks like the data is interpreted as 32-bit FP, causing the left 3/4 of the image to be a garbled version of the actual image, and the right 1/4 to be empty (black).

Steps to Reproduce

This zip file contains a TIFF which was created with Photoshop, saved as 24-bit FP.
Photoshop does produce a warning when selecting that option: "Not all TIFF readers support 24 bit floating point values. Use 24 bit values?"
test.zip

Converting it to PNG using convert produces the following:

While it should look like this:

(this is what convert produces when the input is a 16-bit half-float TIFF)

System Configuration

This was tested on a stock IM 6, but I don't think newer versions (e.g. IM 7) will behave differently.

• ImageMagick version: 6.9.10-14 Q16 x86_64 20181023
• Environment (Operating system, version and so on): Ubuntu

[urban-warrior]

Thanks for the problem report. We can reproduce it and will have a patch to fix it in GIT master branch @ https://github.com/ImageMagick/ImageMagick in a few days. The patch will also be available in the beta releases of ImageMagick @ https://www.imagemagick.org/download/beta/ in a few days.