Change to use kCGImageSourceCreateThumbnailFromImageAlways to solve the issue when HEIC/JPEG contains an embed thumbnail but its size is much smaller than provided maxPixelSize

[dreampiggy]

New Pull Request Checklist

• I have read and understood the CONTRIBUTING guide

• I have read the Documentation

• I have searched for a similar pull request in the project and found none

• I have updated this branch with the latest master to avoid conflicts (via merge from master or rebase)

• I have added the required tests to prove the fix/feature I am adding

• I have updated the documentation (if necessary)

• I have run the tests and they pass

• I have run the lint and it passes (pod lib lint)

This merge request fixes / refers to the following issues: #3036

Pull Request Description

This close #3036

Demo URL(JPEG which contains an embed thumbnail 120x160): http://resource-fat.7kid.com/7kid/moment/img/20206/55e26e85-a962-4d98-a51f-107b55911b24_6.jpg

You can use imagemagic to check the metadata.

• Use kCGImageSourceCreateThumbnailFromImageIfAbsent : Return 120x160

• Use kCGImageSourceCreateThumbnailFromImageAlways: Return 2975x3966

[dreampiggy]

kCGImageSourceCreateThumbnailFromImageIfAbsent Behavior：

1. If there are some embed thumbnail in JPEG/HEIC container, the thumbnail size is 200x200, full image size is 1000x1000, input kCGImageSourceThumbnailMaxPixelSize is 400x400. The final return size will be 200x200, not expected 400x400.

Have to use kCGImageSourceCreateThumbnailFromImageAlways :)

[codecov]

Codecov Report

Merging #3038 into master will decrease coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #3038      +/-   ##
==========================================
- Coverage   84.06%   84.03%   -0.03%     
==========================================
  Files          69       69              
  Lines        7544     7549       +5     
==========================================
+ Hits         6342     6344       +2     
- Misses       1202     1205       +3     

Flag	Coverage Δ
#ios	84.03% <100.00%> (-0.08%)	⬇️
#macos	83.77% <100.00%> (-0.17%)	⬇️

Impacted Files	Coverage Δ
SDWebImage/Core/SDAnimatedImagePlayer.m	89.21% <100.00%> (ø)
SDWebImage/Core/SDImageIOAnimatedCoder.m	85.39% <100.00%> (ø)
...ebImage/Core/SDWebImageDownloaderRequestModifier.m	83.87% <100.00%> (+1.72%)	⬆️
SDWebImage/Core/SDWebImageTransition.m	74.54% <100.00%> (ø)
SDWebImage/Private/SDAsyncBlockOperation.m	85.36% <0.00%> (-4.88%)	⬇️
SDWebImage/Core/SDWebImagePrefetcher.m	90.05% <0.00%> (-1.76%)	⬇️
SDWebImage/Core/SDWebImageManager.m	86.85% <0.00%> (+0.23%)	⬆️
SDWebImage/Core/SDWebImageDownloaderOperation.m	92.64% <0.00%> (+0.29%)	⬆️
... and 2 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update f8fa412...6a22734. Read the comment docs.