Re: PDF Problem

[Rune Zedeler]

Han-Wen Nienhuys skrev:

> Sounds like bullock's manure to me.

You are right - the problem is not really related to this.
I still think that we should change to 1/72 inch instead if 1/72.27 inch 
because this way all staff lines will have same distance on paper and on 
screen, whereas with 1/72.27 it may seldomly happen that two staff lines 
are located 1 pixel closer together than the others. But it happens very 
seldom and is not really the point here.

> I'm not very enthusiastic about a "optimize for screen" option.  I
> think that the sample image you posted looks horrid.

I agree. But this is how acroread renders pdf files.
I have attached three images.
The first is a screenshot of how a lilypond score looks in acroread 
today, the second is a screenshot of how the same score would look with 
screen optimization.
The third is a rendering in high resolution and afterwards scaled down.

The discussion of whether the third is better than the two first I start 
below.
But the discussion that is relevant here is whether the second (screen 
optimized) image looks better than the first (what we have today in 
acroread).

> If you want to
> have certainty that images look like you want them to, you have to
> take control of the rendering process.

I agree, but that is not really possible in all cases.
I think it is a valid point to want to be able to produce pdfs that look 
good in acroread - because acroread is what most people use.
Of course default settings should be to generate high quality paper output.

> That means that you should
> generate large (high DPI) PNG images and scale them down.

This is generally a bad idea when rendering text - because this way you 
will not have any hinting information to generate the image.
(Hinting is the processing of an image to ensure that horizontal and 
vertical lines are located on pixel boundaries).
If you turn off hinting you will get gray shadows along some of the 
horizontal/vertical lines. On the 3rd attached image notice how the 
stems are different. Some of them are thin and black while others are 
thick, grey and blurry.

-Rune