22 November 2005, 00:39 | #1 |
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Algorithm to double the size of a tile based picture smoothely?
A few years back I found a website with information about smoothening out a bitmap picture when you doubled it in size. It doesn't work on photos etc, but for old games with limited palettes it worked very well.
A normal program that doubles will give very chunky pixels. Most programs like Photoshop end up with a smoother picture, but far less crisp and the edges are kind of blurry. If you sharpen you get weird looking edges. A website I visited had some information about a 2x2 filter which worked on pictures with a low number of colours and would do some tricks such as interpolating pixels based on the adjacent pixels. For example, if you have a picture which is 2x2 pixels where the numbers 1 and 2 represent a colour, and you wish to double the picture to 4x4 pixels: Code:
12 21 (double) 1122 1122 2211 2211 (apply 2x2 filter) 1122 1222 <- extra 2 inserted over a 1 2221 <- extra 2 inserted over a 1 2211 I think there was a 4x4 version aswell which ran the 2x2 process twice. It might have been something that is in an emulator or MAME or something. Does anyone recognise this, know a website detailing this process or know exact what it's called etc? I cannot find the site anymore and want to check out exactly what they did! |
22 November 2005, 00:47 | #2 |
HOL-Team
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This one: http://scale2x.sourceforge.net/ ? There are others too, like Eagle or SuperSai.
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22 November 2005, 00:59 | #3 |
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Legend! That's it! Thanks Duke!
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22 November 2005, 09:14 | #4 |
Pirate
Join Date: Jan 2002
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nice info. Shouldn't this thread be put somewhere else, so it's not deleted. Think this is usefull info
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22 November 2005, 09:24 | #5 |
Registered User
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wow, why has'nt this evolved into a standard in graphic programs like Photoshop?
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24 November 2005, 01:45 | #6 |
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Because Photoshop is primarily designed to work with high-res, continous tone, true colour images (ie, photos) and this scaling effect is usless for such imagery.
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24 November 2005, 06:24 | #7 | |
The Ancient One
Join Date: Feb 2002
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Quote:
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24 November 2005, 08:31 | #8 | |
Registered User
Join Date: Sep 2004
Location: Norway
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Quote:
The method is fairly simple, and not limitied to numbers of colours? |
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31 January 2006, 02:46 | #9 |
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Please visit this site, too. IMHO it's the algorithm with the highest quality for increasing sizes of pixeled/paletted images.
http://www.hiend3d.com/ |
31 January 2006, 04:36 | #10 |
[Satan^God]
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The example gfx on the sourceforge website impressed me. Metal Slug rocks! Does anyone know how winuae is using this? It is the "Display->Line Mode->Doubled" option?
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