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PostPosted: Tue Aug 04, 2009 3:19 pm 
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Rusty_Russell wrote:
16:9 is a composite of 4*3 tiles. All of these larger formats are multiples of smaller known tiles.

16 * 9 is 12 (4 * 3) 4*3 tiles. 16 * 10 is 8 (4 * 2) 4*5 tiles. (5*4 is landscape, 4*5 is portrait).


I'm not sure I'm following you here... what do tiles have to do with scaling aspect ratio? The math in your example is doing stuff with multiplication, but that seems to be complicating the problem instead of simplifying it. Aspect ratios (like all ratios) are division, not multiplication: the fraction 16 / 9 cannot be reduced to 4 / 3, so 16:9 is not the same aspect ratio as 4:3

16:12 would reduce fine, which is why an old 21" CRT can show 1600x1200 in the same ratio as 1024x768, they are both 4:3 aspects.

Or am I missing the point?

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PostPosted: Tue Aug 04, 2009 3:25 pm 
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vidroth wrote:
Rusty_Russell wrote:
16:9 is a composite of 4*3 tiles. All of these larger formats are multiples of smaller known tiles.

16 * 9 is 12 (4 * 3) 4*3 tiles. 16 * 10 is 8 (4 * 2) 4*5 tiles. (5*4 is landscape, 4*5 is portrait).


I'm not sure I'm following you here... what do tiles have to do with scaling aspect ratio? The math in your example is doing stuff with multiplication, but that seems to be complicating the problem instead of simplifying it. Aspect ratios (like all ratios) are division, not multiplication: the fraction 16 / 9 cannot be reduced to 4 / 3, so 16:9 is not the same aspect ratio as 4:3

16:12 would reduce fine, which is why an old 21" CRT can show 1600x1200 in the same ratio as 1024x768, they are both 4:3 aspects.

Or am I missing the point?


You are right. In terms of fractions, 16/9 is: (4/3)^2 = (4^2)/(3^2) = (4*4)/(3*3) = 16/9

Nothing to do with multiples of tiles or whatever.

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PostPosted: Tue Aug 04, 2009 3:31 pm 
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I'm sorry that you don't understand me. Just draw it.

Quote:
the fraction 16 / 9 cannot be reduced to 4 / 3, so 16:9 is not the same aspect ratio as 4:3
Yes it can. That's why you have to draw it to understand it.


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PostPosted: Tue Aug 04, 2009 3:40 pm 
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Herohtar wrote:
vidroth wrote:
Rusty_Russell wrote:
16:9 is a composite of 4*3 tiles. All of these larger formats are multiples of smaller known tiles.

16 * 9 is 12 (4 * 3) 4*3 tiles. 16 * 10 is 8 (4 * 2) 4*5 tiles. (5*4 is landscape, 4*5 is portrait).


I'm not sure I'm following you here... what do tiles have to do with scaling aspect ratio? The math in your example is doing stuff with multiplication, but that seems to be complicating the problem instead of simplifying it. Aspect ratios (like all ratios) are division, not multiplication: the fraction 16 / 9 cannot be reduced to 4 / 3, so 16:9 is not the same aspect ratio as 4:3

16:12 would reduce fine, which is why an old 21" CRT can show 1600x1200 in the same ratio as 1024x768, they are both 4:3 aspects.

Or am I missing the point?


You are right. In terms of fractions, 16/9 is: (4/3)^2 = (4^2)/(3^2) = (4*4)/(3*3) = 16/9

Nothing to do with multiples of tiles or whatever.


Ah, that's probably the problem, the square thing. The square root of 16 is 4, the square root of 9 is 3, so it creates a visual relationship between 16:9 and 4:3. But square roots have nothing to do with comparing ratios; to compare the ratios you use simple division. Calculator says 16/9 = 1.777...., 4/3 = 1.333..., so the ratios aren't the same. I'm not arguing with you, I'm just trying to reduce the ideas to their simplest form. 16:9 is 1.77 inches across for every inch down, 4:3 (= 8:6 = 16:12) is 1.33 inches across for every inch down, and fitting one into the other involves ugly squishing.

And I agree with everyone, while we wait for OSMOULNEXT or whatever we're calling it, it would be very nice to get a native widescreen mode hacked into UruCC.

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PostPosted: Tue Aug 04, 2009 3:45 pm 
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See it on paper, then argue with me. :)

I agree with your last point.


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PostPosted: Tue Aug 04, 2009 4:02 pm 
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Rusty_Russell wrote:
See it on paper, then argue with me. :)

I agree with your last point.

That might be where the "am I missing the point?" issue comes in. I will grant you, you can take a bunch of 4:3 tiles and build 16:9, I'm just suggesting it's not in a meaningful way. You can arrange a bunch of 4:1 tiles and make 16:9, or a bunch of 1:1 tiles, for that matter... it just doesn't help you scale one to the other.

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PostPosted: Tue Aug 04, 2009 4:12 pm 
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The key word in your response is scaling. The scaling operation (4:3) on 4:3 is 16:9.
I''d argue that the intent of 16:9 was to preserve the aspect ratio of 4:3: "tiles" of any other size wouldn't do that.


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PostPosted: Tue Aug 04, 2009 4:50 pm 
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This is how scaling works:
Code:
_ |----------2----------|
| |¯¯¯¯¯¯¯­­¯¯¯|¯¯¯¯¯¯¯¯¯¯|
| |   4:3    |    4:3   |
| |          |          |
2 |----------|----------|   = 4:3
| |          |          |
| |   4:3    |    4:3   |
| |__________|__________|
­¯

The same number on each side.

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PostPosted: Tue Aug 04, 2009 5:11 pm 
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That's good. You can see as well as I can that you now have 8:6. Keep going and you will end up eventually with 16:9.

Quote:
If not, the DVD player can reduce scan lines and add letterboxing before sending the image to the TV, made easier by the simple 4:3 aspect ratio between 4:3 and 16:9 (16:9 = 4:3 × 4:3).


It isn't just me.

Signing off here now. This has been more interesting than work. :)


Last edited by Rusty_Russell on Tue Aug 04, 2009 5:43 pm, edited 1 time in total.

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PostPosted: Tue Aug 04, 2009 5:33 pm 
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Code:
*A*
_ |----------2----------|
| |¯¯¯¯¯¯¯­­¯¯¯|¯¯¯¯¯¯¯¯¯¯|
| |   4:3    |    4:3   |
| |          |          |
2 |----------|----------|   = 8:6 is 4:3
| |          |          |
| |   4:3    |    4:3   |
| |__________|__________|
­¯
That is right, but not

*B*
_ |---------------------4---------------------|
| |¯¯¯¯¯¯¯­­¯¯¯|¯¯¯¯¯¯¯¯¯¯|¯¯¯¯¯¯¯¯¯¯|¯¯¯¯¯¯¯¯¯¯|
| |   4:3    |    4:3   |    4:3   |    4:3   |
| |          |          |          |          |
3 |----------|----------|----------|----------|   = 16:9 is not 4:3
| |          |          |          |          |
| |   4:3    |    4:3   |    4:3   |    4:3   |
| |----------|----------|----------|----------|   
| |          |          |          |          |
| |   4:3    |    4:3   |    4:3   |    4:3   |
| |__________|__________|__________|__________|
­¯
It should be

*C*
_ |---------------------4---------------------|
| |¯¯¯¯¯¯¯­­¯¯¯|¯¯¯¯¯¯¯¯¯¯|¯¯¯¯¯¯¯­­¯¯¯|¯¯¯¯¯¯¯¯¯¯|
| |   4:3    |    4:3   |   4:3    |    4:3   |
| |          |          |          |          |
| |----------|----------|----------|----------|
| |          |          |          |          |
| |   4:3    |    4:3   |   4:3    |    4:3   |
4 |----------|----------|----------|----------|   = 16:12 is 4:3
| |          |          |          |          |
| |   4:3    |    4:3   |   4:3    |    4:3   |
| |----------|----------|----------|----------|   
| |          |          |          |          |
| |   4:3    |    4:3   |   4:3    |    4:3   |
| |__________|__________|__________|__________|

or

*D*
­_ |--------------3-----------------|
| |¯¯¯¯¯¯¯­­¯¯¯|¯¯¯¯¯¯¯¯¯¯|¯¯¯¯¯¯¯¯¯¯|
| |   4:3    |    4:3   |    4:3   |
| |          |          |          |
3 |----------|----------|----------|   = 12:9 is 4:3
| |          |          |          |
| |   4:3    |    4:3   |    4:3   |
| |----------|----------|----------|
| |          |          |          |
| |   4:3    |    4:3   |    4:3   |
| |__________|__________|__________|
­¯


What was done:
*A* scale by 2
*B* scale by 3 and stretch x-axel by 133.333%
*C* scale by 4
*D* scale by 3

Like realXCV said.

Zap


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PostPosted: Tue Aug 04, 2009 5:44 pm 
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No. Scaling is only the same if both x and y are the same. The operation is (4:3)(4:3).


Last edited by Rusty_Russell on Tue Aug 04, 2009 5:52 pm, edited 1 time in total.

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PostPosted: Tue Aug 04, 2009 5:50 pm 
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Rusty_Russell wrote:
No. Scaling is only the same if both x and y are the same.


Exactly, which is why 16:9 is not the same as 4:3.

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PostPosted: Tue Aug 04, 2009 5:55 pm 
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What do you mean "Not the same"? It's 4:3 applied to 4:3.

What I will concede though is because of x and y not being the same, something on a 4:3 monitor will be distorted at 16:9 because x is stretched relative to y when you scale up, and I'm also aware that the true ratios are different - 1:1.33 (4:3) is not the same as 1:1.77 (16:9).


Last edited by Rusty_Russell on Tue Aug 04, 2009 6:03 pm, edited 2 times in total.

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PostPosted: Tue Aug 04, 2009 6:01 pm 
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Rusty_Russell wrote:
What do you mean "Not the same"? It's 4:3 applied to 4:3.


16:9 has more width per unit of height than 4:3 does, which is why 16:9 is "widescreen" when 4:3 is not.

http://en.wikipedia.org/wiki/Aspect_ratio_(image)

Sure, you can stack several 4:3 "tiles" together in a way that makes a 16:9 whole, but in no way does that make them the same.

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PostPosted: Tue Aug 04, 2009 6:30 pm 
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I've found a way to explain how I'm looking at this.

Scaling is a matrix operation - you're multiplying a row vector by a row vector - [4 3] * [4 3] = [16 9].

"made easier by the simple 4:3 aspect ratio between 4:3 and 16:9 (16:9 = 4:3 × 4:3)." - quoted earlier.


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