Why not perfect alignment?

On 2009-10-25, dorayme <doraymeRidThis (AT) optusnet (DOT) com.au> wrote:

Can't think of any good reason for the text not to be as crisp for both
*visible* paragraphs at:

http://dorayme.netweaver.com.au/alt/indexAlignment.html

Here is an even purer case:

http://dorayme.netweaver.com.au/alt/indexAlignment2.html

Notice that the background is not set (the phenomena is dependent on the
transparency of the backgrounds to the elements).

It is mildly surprising that blurring occurs, that there is not perfect
registration.

The only theory that comes to my mind does not *quite* satisfy me:
elements are on layers in a fluid which has a refractive index different
to a vacuum.

It's because the glyphs are antialiased. Around the corners they've got
some pixels which are not fully opaque. These are alpha blended with
whatever's behind the text.

So you have one paragraph blended onto a white background, then another
one blended on top of the first one.

Two semi-transparent pixels on top of each other are darker than one on
its own. It's like wearing two pairs of sunglasses at the same time.

Alpha blending is basically alpha * foreground + (1 - alpha) *
background, so the calculations work out like this:

background: 1, 1, 1, 1 (opaque white, r,g,b,a)
pixel at corner: 0, 0, 0, 0.5 (semi-transparent black)

Those two blend together to give a colour of 0.5, 0.5, 0.5. Now blend
the corner pixel on top of that, and you get 0.25, 0.25, 0.25, which is
darker.

In article <slrnhel9e8.39n.spamspam (AT) bowser (DOT) marioworld>,
Ben C <spamspam (AT) spam (DOT) eggs> wrote:

On 2009-10-25, dorayme <doraymeRidThis (AT) optusnet (DOT) com.au> wrote:
Can't think of any good reason for the text not to be as crisp for both
*visible* paragraphs at:

http://dorayme.netweaver.com.au/alt/indexAlignment.html

Here is an even purer case:

http://dorayme.netweaver.com.au/alt/indexAlignment2.html

Notice that the background is not set (the phenomena is dependent on the
transparency of the backgrounds to the elements).

It is mildly surprising that blurring occurs, that there is not perfect
registration.

The only theory that comes to my mind does not *quite* satisfy me:
elements are on layers in a fluid which has a refractive index different
to a vacuum.

It's because the glyphs are antialiased.

Yes, clearly centrally to do with it as I gathered from the various
things we have been yacking about through the thread.

I just downloaded Opera 10 at last and I notice it does the same thing
as Opera 9 in this regard, it does *not* do the transparancy dance
around real HTML letters. There were references about this in the
thread, (that Opera does not engage with the OSs facilities in this
regard. No jaggedy jag).

Anyway, since you revive the matter, let me make a quick experiment with
an anti-aliased png that is made to be transparent:

<http://dorayme.netweaver.com.au/alt/indexAlignment_antiAlias.html>

cf.

<http://dorayme.netweaver.com.au/alt/indexAlignment_no-antiAlias.html>

You might notice that in this case, Opera 10, while not doing the
overlaying jaggedy jag with HTML text, *does* do it with the first of
the last pair of URLs where just pics are involved.

--
dorayme

On 2009-10-31, dorayme <doraymeRidThis (AT) optusnet (DOT) com.au> wrote:

In article <slrnhel9e8.39n.spamspam (AT) bowser (DOT) marioworld>,
Ben C <spamspam (AT) spam (DOT) eggs> wrote:

On 2009-10-25, dorayme <doraymeRidThis (AT) optusnet (DOT) com.au> wrote:
Can't think of any good reason for the text not to be as crisp for both
*visible* paragraphs at:

http://dorayme.netweaver.com.au/alt/indexAlignment.html

Here is an even purer case:

http://dorayme.netweaver.com.au/alt/indexAlignment2.html

Notice that the background is not set (the phenomena is dependent on the
transparency of the backgrounds to the elements).

It is mildly surprising that blurring occurs, that there is not perfect
registration.

The only theory that comes to my mind does not *quite* satisfy me:
elements are on layers in a fluid which has a refractive index different
to a vacuum.

It's because the glyphs are antialiased.

Yes, clearly centrally to do with it as I gathered from the various
things we have been yacking about through the thread.

I just downloaded Opera 10 at last and I notice it does the same thing
as Opera 9 in this regard, it does *not* do the transparancy dance
around real HTML letters. There were references about this in the
thread, (that Opera does not engage with the OSs facilities in this
regard. No jaggedy jag).

I get the same thing in Opera 9.50 on GNU/Linux as in other browsers,
with your original text example-- it looks all jaggedy because the
semi-transparent bits of the glyphs are too dark as a result of being
blended on top of each other several times.

In article <slrnheo2a0.34o.spamspam (AT) bowser (DOT) marioworld>,
Ben C <spamspam (AT) spam (DOT) eggs> wrote:

I get the same thing in Opera 9.50 on GNU/Linux as in other browsers,
with your original text example

You mean the latest URL with the pngs?

There was some evidence that the text jaggedy look was related to the
font-smoothing facilities in Windows. On my Mac there seems no way to
turn what is called "font-smoothing" quite off. You can alter the nature
or degree of it. I experimented on this subtler basis but saw no useful
changes.

In Opera on the Mac, text looks its normal smooth extremely pleasing
self in all situations. So something is supplying font-smoothing.
Without it, text looks qhastly on screen. But there is no piling up of
semi-transparent bits to give the effect being discussed. And nor does
this happen with the pngs I made, the url to which you snipped and I
have momentarily lost.

--
dorayme

On 2009-10-31, dorayme <doraymeRidThis (AT) optusnet (DOT) com.au> wrote:

In article <slrnheo2a0.34o.spamspam (AT) bowser (DOT) marioworld>,
Ben C <spamspam (AT) spam (DOT) eggs> wrote:

I get the same thing in Opera 9.50 on GNU/Linux as in other browsers,
with your original text example

You mean the latest URL with the pngs?

The pngs were jaggedy too, but so was the text (the actual text, in the
example you posted earlier).

There was some evidence that the text jaggedy look was related to the
font-smoothing facilities in Windows. On my Mac there seems no way to
turn what is called "font-smoothing" quite off. You can alter the nature
or degree of it. I experimented on this subtler basis but saw no useful
changes.

In Opera on the Mac, text looks its normal smooth extremely pleasing
self in all situations. So something is supplying font-smoothing.

I think you nearly always get some kind of font antialiasing on anything
worth its salt these days.

Without it, text looks qhastly on screen. But there is no piling up of
semi-transparent bits to give the effect being discussed. And nor does
this happen with the pngs I made, the url to which you snipped and I
have momentarily lost.

Sorry! I'm now quite confused. I saw nothing but the expected effect of
alpha blending the same thing on top of multiple copies of itself both
with pngs and with actual text in all browsers I tried including Opera.

In article <slrnhepgum.34o.spamspam (AT) bowser (DOT) marioworld>,
Ben C <spamspam (AT) spam (DOT) eggs> wrote:

On 2009-10-31, dorayme <doraymeRidThis (AT) optusnet (DOT) com.au> wrote:
In article <slrnheo2a0.34o.spamspam (AT) bowser (DOT) marioworld>,
Ben C <spamspam (AT) spam (DOT) eggs> wrote:

I get the same thing in Opera 9.50 on GNU/Linux as in other browsers,
with your original text example

You mean the latest URL with the pngs?

The pngs were jaggedy too, but so was the text (the actual text, in the
example you posted earlier).

*All* the pngs were jaggedy? I would have thought one of the
anti-aliased ones that was *not* under a pile of positioned similars
would show as I prepared it, anti-aliased. That sort of surprises me!
(And sort of not too, considering the surprises I have when moving from
Mac platforms to others. It is a bit of a worry this, making nice
graphics if only some platforms play along! Basically communication
across platforms is pretty hard, eh?) What is your carrier-pigeon nest
address? <g>

The idea of my pngs was to get away from HTML text for comparison, to
see what happens with pictures of text prepared in both anti-aliased
format and non-anti-aliased format in the context of elements piled on
top of each other in the way absolute positioning makes possible. In
particular to see if the piling up acts as in HTML text.

There was some evidence that the text jaggedy look was related to the
font-smoothing facilities in Windows. On my Mac there seems no way to
turn what is called "font-smoothing" quite off. You can alter the nature
or degree of it. I experimented on this subtler basis but saw no useful
changes.

In Opera on the Mac, text looks its normal smooth extremely pleasing
self in all situations. So something is supplying font-smoothing.

I think you nearly always get some kind of font antialiasing on anything
worth its salt these days.

Without it, text looks qhastly on screen. But there is no piling up of
semi-transparent bits to give the effect being discussed. And nor does
this happen with the pngs I made, the url to which you snipped and I
have momentarily lost.

Sorry! I'm now quite confused. I saw nothing but the expected effect of
alpha blending the same thing on top of multiple copies of itself both
with pngs and with actual text in all browsers I tried including Opera.

Perhaps you saw the isolated statically positioned png as smooth and I
am being unnecessarily confused?

Anyway, sounds like your Opera is different to mine!

--
dorayme

On Oct 25, 12:31*pm, j... (AT) macunlimited (DOT) net (j) wrote:

dorayme <doraymeRidT... (AT) optusnet (DOT) com.au> wrote:

Here is one theory that suggests itself from Upsdell's observation: I am
seeing an attempt by my OS to do smoothy things with the edges of the
type but it gets confused by doing it in one spot. Or does it do it to
two sets of identical text but somehow the browser itself gets confused
when summing the two sets?

Here's a theory. Text at small sizes isn't pure black due to Mac OSX
font smoothing. Instead the pixels forming the characters have various
degrees of transparency. When you overlay two identical characters, a
semi-transparent pixel will become darker (like overlaying two
semi-transparent layers in photoshop). The lighter edge pixels become
darker and make the font look jaggy.

To see this more clearly (on a Mac), press Cmd-Opt-8 to switch on Zoom,
then press Cmd-Opt-+ repeatedly to zoom in (you may need to alter the
zoom settings in the Universal Access control panel).

<quote src="http://www.imagemagick.org/Usage/antialiasing/">Anti-
aliasing involves using a mix of colors and transparences to try and
smooth the 'stair case' or 'jaggies' effect of slanted lines and color
boundaries. If only two colors are available no anti-aliasing can NOT
happen! </quote>
Is that only true concerning ImageMagick?
Or anywhere?

On 2009-11-01, dorayme <doraymeRidThis (AT) optusnet (DOT) com.au> wrote:

In article <slrnhepgum.34o.spamspam (AT) bowser (DOT) marioworld>,
Ben C <spamspam (AT) spam (DOT) eggs> wrote:

On 2009-10-31, dorayme <doraymeRidThis (AT) optusnet (DOT) com.au> wrote:
In article <slrnheo2a0.34o.spamspam (AT) bowser (DOT) marioworld>,
Ben C <spamspam (AT) spam (DOT) eggs> wrote:

I get the same thing in Opera 9.50 on GNU/Linux as in other browsers,
with your original text example

You mean the latest URL with the pngs?

The pngs were jaggedy too, but so was the text (the actual text, in the
example you posted earlier).


*All* the pngs were jaggedy? I would have thought one of the
anti-aliased ones that was *not* under a pile of positioned similars
would show as I prepared it, anti-aliased.

No, those weren't jaggedy-- only the ones that were several pngs on top
of each other.

[...]

Sorry! I'm now quite confused. I saw nothing but the expected effect of
alpha blending the same thing on top of multiple copies of itself both
with pngs and with actual text in all browsers I tried including Opera.

Perhaps you saw the isolated statically positioned png as smooth and I
am being unnecessarily confused?

Yes, the isolated one was smooth.

On 2009-11-01, Jan C. Faerber <faerber.jan (AT) gmail (DOT) com> wrote:

On Oct 25, 12:31*pm, j... (AT) macunlimited (DOT) net (j) wrote:
dorayme <doraymeRidT... (AT) optusnet (DOT) com.au> wrote:

Here is one theory that suggests itself from Upsdell's observation: I am
seeing an attempt by my OS to do smoothy things with the edges of the
type but it gets confused by doing it in one spot. Or does it do it to
two sets of identical text but somehow the browser itself gets confused
when summing the two sets?

Here's a theory. Text at small sizes isn't pure black due to Mac OSX
font smoothing. Instead the pixels forming the characters have various
degrees of transparency. When you overlay two identical characters, a
semi-transparent pixel will become darker (like overlaying two
semi-transparent layers in photoshop). The lighter edge pixels become
darker and make the font look jaggy.

To see this more clearly (on a Mac), press Cmd-Opt-8 to switch on Zoom,
then press Cmd-Opt-+ repeatedly to zoom in (you may need to alter the
zoom settings in the Universal Access control panel).

quote src="http://www.imagemagick.org/Usage/antialiasing/">Anti-
aliasing involves using a mix of colors and transparences to try and
smooth the 'stair case' or 'jaggies' effect of slanted lines and color
boundaries. If only two colors are available no anti-aliasing can NOT
happen! </quote
Is that only true concerning ImageMagick?
Or anywhere?

Anywhere.

On Nov 5, 10:40*pm, Ben C <spams... (AT) spam (DOT) eggs> wrote:

quote src="http://www.imagemagick.org/Usage/antialiasing/">Anti-
aliasing involves using a mix of colors and transparences to try and
smooth the 'stair case' or 'jaggies' effect of slanted lines and color
boundaries. *If only two colors are available no anti-aliasing can NOT
happen! </quote
Is that only true concerning ImageMagick?
Or anywhere?

Anywhere.

Oh - great!
Just the imagemagick manual is so huge that I will finish learning in
about 2021.
Just wanted to find a way to resize my pics from a digi cam.
But it should work.
I pressed 'Ctrl + D' at that page!