parallax/jsPDF

exif orientation is handled incorrectly

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#3795 opened on Nov 21, 2024

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 (7 comments) (2 reactions) (0 assignees)JavaScript (28,280 stars) (4,596 forks)batch import
Feature Requesthelp wanted

Description

jspdf handles exif orientation and correctly flips width and height. However, it does not actually rotate the image. Instead it just stretches the unrotated image into its rotated shape.

This issue has been rised twice already but it seems that nobody realized that the image is not correctly rotated

In both issues you can actually see, that albeit the image dimension was rotated, the content was not. I encountered the issue when using svg2pdf.js. You can also see another example in the issue I raised: https://github.com/yWorks/svg2pdf.js/issues/315. The orientation is correct, the content is still unrotated and just stretched

Contributor guide

Tech stack
javascript
Domain
frontend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
JavaScriptImage processingEXIF orientation
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
The fix should be applied in the image processing module of jsPDF, likely in files related to JPEG or image handling (e.g., src/libs/JPEGEncoder.js). The developer should examine how EXIF orientation is currently handled and replace the dimension swap with actual rotation of the image pixel data, using Canvas API or similar. Refer to the linked issues (#2815, #2740) and the svg2pdf.js issue for examples of the incorrect behavior.