createFrameAtIndex has a bug

[AKZHW]

 "  decodingOptions[(__bridge NSString *)kCGImageSourceCreateThumbnailWithTransform] = @(preserveAspectRatio);
    CGFloat maxPixelSize;
    if (preserveAspectRatio) {
        CGFloat pixelRatio = pixelWidth / pixelHeight ;
        CGFloat thumbnailRatio = thumbnailSize.width / thumbnailSize.height;
        if (pixelRatio > thumbnailRatio) {
            maxPixelSize = thumbnailSize.width;
        } else {
            maxPixelSize = thumbnailSize.height;
        }
    } else {
        maxPixelSize = MAX(thumbnailSize.width, thumbnailSize.height);
    }
    decodingOptions[(__bridge NSString *)kCGImageSourceThumbnailMaxPixelSize] = @(maxPixelSize);
    decodingOptions[(__bridge NSString *)kCGImageSourceCreateThumbnailFromImageAlways] = @(YES);
    imageRef = CGImageSourceCreateThumbnailAtIndex(source, index, (__bridge CFDictionaryRef)[decodingOptions copy]);"

There is a precision loss problem in this line ” CGFloat pixelRatio = pixelWidth / pixelHeight ; “

then "

        if (pixelRatio > thumbnailRatio) {
            maxPixelSize = thumbnailSize.width;
        } else {
            maxPixelSize = thumbnailSize.height;
        }"

should after Calculate the width and height in the same proportion, and then calculate maxsize

[dreampiggy]

Maybe #3262 already solve this.
Check v5.12.0+ again ?

[AKZHW]

only fix precision loss problem, but calculate maxPixelSize has a problem,

I think should use this code
CGFloat maxPixelSize;
if (preserveAspectRatio) {
CGFloat pixelRatio = pixelWidth / pixelHeight;
CGFloat thumbnailRatio = thumbnailSize.width / thumbnailSize.height;
if (pixelRatio > thumbnailRatio) {
maxPixelSize = MAX(thumbnailSize.width, thumbnailSize.width / pixelRatio);
} else {
maxPixelSize = MAX(thumbnailSize.height * pixelRatio, thumbnailSize.height);
}
} else {
maxPixelSize = MAX(thumbnailSize.width, thumbnailSize.height);
}

[AKZHW]

for example my picture origin size 360 * 136 , request size 200 * 80， the result should get 200 * 75， bug use you code get 80 * 30

[dreampiggy]

I think you're right.

The documented design of that preserveAspectRatio should use the latest near but not larger value of one edge. So current these code:

            if (pixelRatio > thumbnailRatio) {
                maxPixelSize = thumbnailSize.width;
            } else {
                maxPixelSize = thumbnailSize.height;
            }

will only assume to use another edge's length as input thumbnail pixel width. Which will make the final thumbnail smaller than you expected.

[dreampiggy]

Fixed in 5.12.6