[Digikam-users] Re: aspect ratio crop tool

[Dan McDaniel]

On Mon 16.May.11 13:03, David Kerber wrote:
>On 5/16/2011 12:51 PM, Remco Viëtor wrote:
>> on Monday 16 May 2011, David Kerber wrote:
>>> On 5/16/2011 11:42 AM, Dan McDaniel wrote:
>>>>
>>>> I have noticed that very often the Aspect Ratio Crop Tool does not crop
>>>> accurately, but will be off by pixel.  So, for example, if I want  a 5:4
>>>> aspect ratio which should be 1.25 the crop will be off by a pixel and
>>>> give a ratio of 1.2499 or such.
>>>>
>>>> This small difference does not affect the look of the image, but when I
>>>> send it to the photo service to be printed the software detects that it
>>>> is not in the correct ratio and each time I have to tell it that it's OK
>>>> to crop the image.
>>>>
>>>> Has anyone else noticed this? I'm using 1.2.0 on Debian and 1.9.0 on
>>>> Fedora and both exhibit this behavior.
>>>>
>>>
>>> Are your originals' sizes such that 1.25 will give an exact pixel
>>> result, and not have to be rounded either up or down to get to a whole
>>> pixel?
>>>
>>
>> the size of the original isn't important, the size of the crop is:
>> if you take a length of 1003 pixels, there's no way you can get the 5:4 ratio
>> exact on pixel level, as we only use whole pixels: you'd have to make the long
>> edge either 1000 (giving 800 for the short side) or 1005 (804 for the short
>> size).
>
>Yes, true.  It looked to me like the OP was leaving on of the dimensions
>of his original image unchanged, and trying to crop only the other
>dimension.  That would work only if the original dimensions were such
>that a factor of multiplying or dividing by 1.25 would give an integer
>result.
>
No, I was trying to crop a box out of the original at the selected
aspect ratio and was puzzled when it didn't crop exactly. Checking the
option box makes it work as I expected it to work by default.

Thanks to all who replied.

Dan
>
>> Already in 1.9.0 (and a few versions before iirc) there is the 'exact ratio'
>> option, which indeed limits the sizes you can pick so that you get the exact
>> ratio specified.
>
>I didn't know that; it would be handy.
>
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-- 
Dan McDaniel
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