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Old 03-09-2019, 10:37 PM   #1695
Loyd
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Loyd My eyes! My eyes! The light is just too bright!Loyd My eyes! My eyes! The light is just too bright!Loyd My eyes! My eyes! The light is just too bright!Loyd My eyes! My eyes! The light is just too bright!Loyd My eyes! My eyes! The light is just too bright!Loyd My eyes! My eyes! The light is just too bright!Loyd My eyes! My eyes! The light is just too bright!Loyd My eyes! My eyes! The light is just too bright!Loyd My eyes! My eyes! The light is just too bright!Loyd My eyes! My eyes! The light is just too bright!Loyd My eyes! My eyes! The light is just too bright!
 
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Quote:
Originally Posted by willus View Post
Your confusion is understandable, and you are correct--these options are all inter-related. The options have grown over time in order to try and simplify things, but in some ways they have confused things.

-idpi is simply the dpi that the source dpi is rendered internally in k2pdfopt. You shouldn't really need to specify this since it defaults to 2x your output resolution, which should always be sufficient.

-dr is a quick way to increase the resolution of your converted file without changing the page dimensions. You can also do this with -odpi, but the affect of -odpi depends on whether you have specified the output page size in pixels or in inches/cm. If you've specified the output page size in pixels (which is the default), increasing -odpi will cause the output content to magnify. If you've specified the output page size in inches/cm, increasing -odpi will behave the same as -dr -- it will increase the resolution, but not magnify the content. Using -dr will always increase resolution, either way.

-fs is just another way to specify the magnification of the output content relative to the output page size--by using font size rather than dpi if you prefer to do it that way.

-mag is yet another way to increase magnification of the output content. Again, you can achieve the same effect using -odpi, but only if you've specified the output page size in pixels. If you use -mag, it will increase the output content magnification either way you specify the output page size (pixels or inches/cm).

In general, you should leave -idpi set to its default and only ever specify one of -odpi, -fs, or -mag. This will set the size of our output content relative to the output page size. Then you can optionally adjust -dr if the resolution needs adjusting. Equivalently, you could specify only -odpi and the device page size in inches/cm. For instance, the defaults for the latest version of k2pdfopt are Kindle Paperwhite 3, which is 1016 x 1364 pixels at 300 dpi, and therefore 3.39 x 4.55 inches. These two commands are an equivalent way to double the output resolution from the default, keeping the 3.39 x 4.55-inch page size:

k2pdfopt -w 3.39in -h 4.55in -odpi 600 myfile.pdf

k2pdfopt -dr 2 myfile.pdf

Whereas these two commands are an equivalent way to double the output magnification from the default, effectively making the output page 1.7x2.28 inches, so that when it is viewed on the 3.39x4.55-inch screen it is magnified by 2x in each dimension:

k2pdfopt -odpi 600 myfile.pdf

k2pdfopt -mag 2 myfile.pdf
Thanks for taking time to explain in details these options. I see really clear now!

As conversion software, K2pdfopt is very powerful... Thank you for it.
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