Hi, I am failing to understand why you give a compression ratio as a percentage. As you can see from above, this simply causes confusion to the users of your software because it is not standard practice. I know how you come up with your percentage; however you are using incorrect terminology. Compression ratio is never given as a percentage; SPACE SAVING is given as a percentage.
Compression ratio as:
Compression Ratio = (Uncompressed Size)/ (Compressed Size) (i.e. 5.25:1)
SAPCE SAVINGS = 1-(Compressed Size/Uncompressed Size) (*100 if you want to see %)
This gives the user a SPACE SAVING percentage, which most understand over what your software shows during a compression. What you are doing is showing the ratio of space STILL BEING USED as a percentage of original by the files after compression, not the percentage that is being SAVED. I believe most people could care less about the ratio still being used; they want to know how much free space they are gaining. Personally, I want to know what % of space I am GAINING because most of the time people are compressing due to LOW DISK SPACE. I simply will look at post file size and quantify what the files still take up on my drives.
The method you use does the opposite of what one might expect. If the file(s) have a high ability to be compressed, 7Z shows a LOW "compression ratio percentage", like 11%. There is no logic in this; a HIGHER COMPRESIION RATIO means BETTER COMPRESSION, or a HIGHER PERCENTAGE of saved space. You are displaying a LOWER COMPRESSION RATION PERCENTAGE and people are supposed to know that this translates into a HIGHER COMPRESSION RATIO?. Its not logical. What you are using is an inverse relationship and is not based on compression ratio terminology. You need to at least add the "1-" to give the user something they can understand as "space savings".
Heck why not go even further and show exaclty HOW MUCH SPACE has been gained with the compression, which is what most people want to know!
"Original Size = 1GB, Compresesed Size = .25GB, SPACE GAINED = .75GB"
That is what I want to see, what I'm getting back.
May I suggest that to make this easier to understand for the average person that you use this:
1-(compressed size/Uncompressed size)*100 = PERCENT SPACE SAVINGS
Users simply look at post files size to quantify what the files take up after the compression is finished. The range of 0 to 1.1 carries no quantifiable logical for end users and it adds confusion.
MP