基于 alexcorvi/heic2any 的扩展版本，增加了PDF转换功能
Client-side (browser-side, using Javascript) conversion of HEIC/HEIF image files to JPEG, PNG, GIF, or PDF.
High Efficiency Image File Format (HEIC) is a new image container format from the developers of MPEG, a popular audio and video compression standard. HEIC will be used by default on new photos on iOS 11, and it’s designed to save you storage space. As it’s a new container format, there will be some incompatibilities along the way, and Apple does a good job at handling most of these. iOS 11 will automatically share HEIC files as the default JPEG format for apps, so you won’t notice anything when you share a photo on Twitter or Instagram. iOS 11 also offers to automatically transfer photos and videos in a compatible format for Mac or PC users, useful if you’re simply plugging your iPhone into your laptop or PC. theverge.com
While developing some web-based application that should be able to handle mobile uploads, I've come across a problem where browsers can not display certain images uploaded from the iPhone, after investigating through the issue, I noticed that that my iPhone was giving a heic formatted image.
Currently there are zero web browsers that support HEIC photos. Even Apple's latest-greatest version of Safari can't decode HEIC and doesn't recognize the "image/heic" mimetype. A solution that came across my mind is to utilize the benefits of high resolution and low storage of heic images when storing in the server and client-side conversion to JPEG for viewing on the browser.
This library would typically be used for viewing purposes, as currently it's not focusing on copying any metadata from the original heic file to the output jpeg, gif, png, or pdf. The development process of this library is focusing on viewing a browser-consumable version of an heic file, and doing it quickly, asynchronously (using web workers) and accurately. This library would even convert heic containers that have multiple heic images into an animated gif or multi-page pdf.
However, if you're planning on storing the files (not just viewing them), I'd suggest you look for a server-side tool, or you try to get your hands dirty and contribute to this library and make it capable of storing metadata.
Last but not least, this tool is specifically for the browser environment, it will not work in node environment.
This library now supports converting HEIC images directly to PDF format with the following features:
- PDF Page Formats: Supports A4, Letter, and original image size
- Page Orientation: Portrait or landscape orientation
- Quality Control: Adjustable image quality (0.1 - 1.0)
- Multiple Images Handling:
multiple: false- Only exports the first image to PDFmultiple: true- Exports all images from HEIC file, creates separate PDF for each image
- Automatic Image Fitting: Images are automatically centered and scaled to fit the page while maintaining aspect ratio
import heic2any from 'heic2any';
// Convert to PDF with A4 format
const pdfBlob = await heic2any({
blob: heicFile,
toType: "application/pdf",
quality: 0.9,
pdfPageFormat: "a4",
pdfOrientation: "portrait"
});
// Convert multiple images to separate PDFs
const pdfBlobs = await heic2any({
blob: heicFile,
toType: "application/pdf",
multiple: true,
pdfPageFormat: "original"
});Those are the known issues of the library, pull requests are welcome:
- Library doesn't take any metadata from the original file, resulting file doesn't have any metadata.
- Library can convert bursts into an animated
gif, however when aheicanimation is given (like the stars animation in the demo) library will only take the first shot of the animation. - Support for IE11 is not here yet.
This project is a fork of alexcorvi/heic2any.
Based on the original work, I have made some improvements and added a new feature:
- HEIC to PDF conversion
Many thanks to the original author for their great work! 5. The library requires a browser-like environment to work, i.e. it needs the existence of the DOM and window object.