LÖVE

TechnoCat wrote:

tentus wrote:@kikito/Technocat: Bad aliasing drives me nuts. How would you do it in code, so I can see how the results turn out? Also, PNG-8 has some well-known gamma problems (http://hsivonen.iki.fi/png-gamma/). This might not be true within Love, but I still shy away from the format.

You can't have soft edges with no alpha channel.
But an easy way to turn green into transparent would be to use http://love2d.org/wiki/ImageData:mapPixel

Code: Select all

function pixelFunction(x, y, r, g, b, a)
    if r==0 and g==255 and b==0 then
        a = 0
    return r, g, b, a
end

ImageData:mapPixel( pixelFunction )

tentus wrote:Would you mind compressing the other one, for comparison's sake?

tentus wrote:Kikito suggested it could be done in Lua, if I understood him correctly. I'm guessing you'd have to track the previous pixel, and on color change you would use an intermediate alpha with the previous color? That would lead to serious blurring though...

TechnoCat wrote: Another thing you can try is to make the image at half size, and then have LOVE scale it to 2x with linear filtering. Eh? Maybe have LOVE do the aliasing?

thelinx wrote: The other one being?

function blur(sourceImage)
  imageData = <create a new imagedata with the same with and height as sourceImage>
  for each pixel(x,y) in sourceImage
    -- "adjacent" can be 4 pixels, or 8 pixels, if you include the diagonal ones. In corners and borders, they're less pixels.
    <obtain the r,g,b,a values of the pixels adjacent to (x,y) in sourceImage> 
    imageData[x][y] = <the average rgba values of the adjacent pixels in sourceImage>
  end
  return imagedata
end

tentus wrote:That would lead to serious blurring though...

Robin wrote:I don't know anything about this, but wouldn't it be possible to use the g-channel completely for alpha? As in:

Code: Select all

function pixelFunction(x, y, r, g, b, a)
    return r, 0, b, g -- no green?
end

ImageData:mapPixel( pixelFunction )

Probably not, eh?

function pixelFunction(x, y, r, g, b, a)
    return r, r, b, g --double r or b to make it grey
end

ImageData:mapPixel( pixelFunction )

TechnoCat wrote:*Ring ring ring* Hey, it's me gif!

TechnoCat wrote:

Robin wrote:I don't know anything about this, but wouldn't it be possible to use the g-channel completely for alpha? As in:

Code: Select all

function pixelFunction(x, y, r, g, b, a)
    return r, 0, b, g -- no green?
end

ImageData:mapPixel( pixelFunction )

Probably not, eh?

Close, but it would probably need to be:

Code: Select all

function pixelFunction(x, y, r, g, b, a)
    return r, r, b, g --double r or b to make it grey
end

ImageData:mapPixel( pixelFunction )

You could probably write the image out to take 4 bits per pixel in a binary file, 2 for greyscale, 2 for alpha. That could make a really small file.


*Ring ring ring* Hey, it's me gif!

windwaker.gif

function pixelFunction(x, y, r, g, b, a)
    return r, r, b, (255 - g) --double r or b to make it grey
end

ImageData:mapPixel( pixelFunction )

tentus wrote:Wouldn't you also need to invert the g value, since 255 alpha is opaque?

Code: Select all

function pixelFunction(x, y, r, g, b, a)
    return r, r, b, (255 - g) --double r or b to make it grey
end

ImageData:mapPixel( pixelFunction )

Also, I'm consistently surprised at how often I use GIF at work, it's a great image format.