Image Orientation meta info are removed with all possible configuration

[realamirhe]

First of all THANKS FOR THIS GREAT PACKAGE

Describe the bug
By all closed issues about Image Orientation change, it seems to have a little problem of saving image meta info for sample image in the demo page

To Reproduce
I download the image ant rotate it 90 deg to the right

1. Input image (original image)
2. Output image (compressed image)
3. Output image (compressed image) [checkOrientation=false]
4. Output image (compressed image) [strict=false]
5. Output image (compressed image) [checkOrientation=false & strict=false]

Upload each image in metapicz and check the EXIF section

Expected behavior
For the original Image, the EXIF section is like

Orientation	Horizontal (normal)
XResolution	72
YResolution	72
ResolutionUnit	inches
ExifVersion	0210
FlashpixVersion	0100
ColorSpace	sRGB
ExifImageWidth	600
ExifImageHeight	500

But for the rest of the configuration, no EXIF information can be detected from the image

EXIF data not found.

For the 2 and 4 configurations, we must get EXIF information the same as original, I guess

Screenshots

Desktop (please complete the following information):

• OS: [e.g. Ubuntu]
• Browser [chrome]
• Version [ 88.0.4324.96]

Additional context
All other options remain the same as default options presented in demo page e.g. quality: 0.8.

Is there any way to save orientation without extracting it separately like the solution posted in #65?
I also check all related Issues: #10 #56 #63 #64 #65 #88

[fengyuanchen]

It is designed like this and cannot be changed. The Exif information will be cleared always when the strict option is set to false.

[fengyuanchen]

Exactly, the Compressor.js uses the Browser's native canvas.toBlob API to do the compression work, which means all the Exif information are removed by the canvas.toBlob, and it is a native behaviour that cannot be changed.

[realamirhe]

Thank you @fengyuanchen,
In type 2 Output image (compressed image); I used checkOrientation=true & strict=true .
Should all Exif information be removed in this type too?

[fengyuanchen]

Please read the documentation about the strict option carefully.

[realamirhe]

Let's wrap up everything, I guess I couldn't tell properly what was the problem.

I change the orientation of the image, So I want a method to keep its orientation even after compression.
As far as I know by documentation

Strict Mode keeps original image instead of compressed one
if compression image doesn't satisfy the option we put on width, height , mimeType, minWidth and minHeight.
for example, if the image of 400x20 compresses to 400x40 we use the original image instead if strict mode is true.

checkOrientation
if checkOrientation = true then the orientation of the image is stored and applied after compression.

there are two Notes:

Don't trust this all the time as some JPEG images have incorrect (not standard) Orientation values.
I trust it, it was a demo image and I checked its orientation EXIF before compression.

If the size of target image is too large (e.g., greater than 10 MB), you should disable this option to avoid out-of-memory crash.
The image size was not greater than 10 MB, hence we hope to have no memory issue.

---

I brute force on all the possible combinations of strict and checkOrientation on the issue I asked, and all of them remove the orientation.

It is designed like this and cannot be changed. The Exif information will be cleared always when the strict option is set to false.
Although It wasn't clear by documentation, you said if strict=false then all Exif information will be cleared

what you said seemed different from documentation, but if consider it as a true statement, so I hope the strict=true with one possible value for checkOrientation gonna keep the orientation. One checkOrientation=true (probably this one by doc) or one with checkOrientation=false.

I think all the process I've taken was meaningful, although it was not very smart.

The only solution I think gonna work, is to keep the EXIF on our side and apply that after compression.
If this is the case, I guess its probably better to mention it more clearly in the documentauton.

[fengyuanchen]

Just one new note for this:

The image's Exif information will be removed after compressed, so if you need the Exif information, you may need to upload the original image as well.