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  1. #1
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    Cropping in Irfanview 3.99

    I have some photographs of individual people at about 2600w x 2000h which I want to crop and reduce to about 120w x 150h using Irfanview 3.99. to put them on our website in the usual Crooks' Gallery / "Know Your Enemy" format.

    It's quite easy to draw a rectangle round the required content, do Edit -> Crop Selection, then do Image -> Resize/Resample and choose 120 for the width.

    BUT it would be nice to know the size and aspect ratio of the rectangle you have drawn AND to be able to superimpose a grid (say 3 x 4) on top of the rectangle, so you can see more precisely the locations of individual parts of the face, for example.

    Does anyone know if either or both of these can be done? I can't find it anywhere in the Help...

    Thanks

    John

    PS Example follows
    Attached Images Attached Images
    <font face="Script MT Bold"><font color=blue><big><big>John</big></big></font color=blue></font face=script>

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  2. #2
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    Re: Cropping in Irfanview 3.99

    While dragging a rectangle, IrfanView's title bar displays

    XY: (mouse x, mouse y) (width x height pixels, aspect ratio)

    After releasing the mouse button, it displays

    Filename - IrfanView (Selection: top, left; width, height; aspect ratio)

    I don't think there's a grid available.

  3. #3
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    Re: Cropping in Irfanview 3.99

    <img src=/S/doh.gif border=0 alt=doh width=15 height=15> Thanks, Hans.

    It's amazing what you don't notice when you're concentrating on the central part of the picture...

    John
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    Re: Cropping in Irfanview 3.99

    I do not know how Irfanview does its resizing, but doing a 20 to 1 resizing in one step often produces a poorer resulting image than if it were done in several smaller steps. This obviously depends on the image content as well. You might compare your one step result with, say reducing the image by half for the first few steps.

    Paul

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    Re: Cropping in Irfanview 3.99

    I had heard exactly the opposite, that the more times you resize, the more decisions have to be made about transforming a group of pixels into one, and thus the poorer will be the resultant image quality!

    Fortunately we are not talking about high-quality images here, but mug-shots done by ME which just need to end up just above passport-photo size on the website (and the file-sizes come out at 12 KB, pleasingly)...

    John
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    Re: Cropping in Irfanview 3.99

    Resizing vs. cropping is two different worlds. The cropping, the act of throwing way a part of the image will NOT change pixel count per inch, as the resizing will.

    Now running HP Pavilion a6528p, with Win7 64 Bit OS.

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    Re: Cropping in Irfanview 3.99

    Yes Dave, but he did indicate in the original post that he was doing both cropping and resampling. Not knowing the original photo, it could well have been a large pixel count image even after cropping and the resample to 120 pixels would have been a large change.

    Paul

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    Re: Cropping in Irfanview 3.99

    By analogy, in PS elements, there are two tools you can use to crop. One is specifically designed for cropping, and is completely "freehand" in its dimensions. The other is the rectangular selection (Marquee) tool, and it can be constrained either to a particular size or to a ratio (e.g., 4:3). You might find that you can choose the ratio you want in Irfanview as well.

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    Re: Cropping in Irfanview 3.99

    My method seemed logical (to me!)
    a) select that rectangular part of the original photo which I wanted to keep
    [img]/forums/images/smilies/cool.gif[/img] resize this rectangle down to the size I need to put on the website

    Should I have done it a different way?

    John
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  10. #10
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    Re: Cropping in Irfanview 3.99

    Hi John

    Your logic is fine.

    This Macromedia's definition.
    <hr>
    Resampling adds pixels to or subtracts pixels from a resized bitmap to match the appearance of the original bitmap as closely as possible. Resampling a bitmap to a higher resolution typically causes little loss of quality. Resampling to a lower resolution, however, always causes data loss and usually a drop in quality.
    <hr>

    Your image of the lovely Lorraine is very small is size and attributes and I honestly don't think there will be a great loss in quality. When I am making my little animations I am often asked by Fireworks if I want to resample the pasted image and a lot of the time I don't bother due to the size of the image and improving the sample rate will only add file size with no real benefits to the finished product
    Jerry

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    Re: Cropping in Irfanview 3.99

    John,
    Your logic is perfect.
    My original comment was only to point out that an approach used by some professionals when they have to dramatically down size an image and keep the quality high is to do the following: Resample the image in steps, never reducing the size by more than 50%. After each step apply an unsharp mask filter. This approach does have more decisions to be made about transforming pixels, but with more information available and the right filters the result in better image quality.

    Paul

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