PNG-24 Alpha support for IE

Seb (Sébastien Grosjean) — Tue, 04 Apr 2006 02:03:26 GMT

What so much webdesigners dream about!
Get alpha channel on web, that's possible with PNG-24 images and this trick.
BE CAREFUL: that seem to work only for 10 images per page.



  # Display PNG-24 images with alpha channel on IE

  # BE CAREFUL: with this trick, only 10 PNGs seems to be supported by IE

  # Don't forget to set the size of your div

  def transpng(id, png)

    '

    '

  end

Using transparent gif/png with Image's blitting

korakot (Korakot Chaovavanich) — Thu, 09 Feb 2006 13:03:39 GMT

pys60's Image class will load a transparent gif/png
just like a non-transparent one.
But its blit() method accept a mask paramenter.
I have talked about this in a previous snippet.

The missing link is to create a mask automatically
from the Image. It's typically the top-left pixel.
You can use Image's getpixel() which is undocumented.
I show typical use of getpixel here.

Combine them all, here's the automask function.



def automask(im):

    width, height = im.size

    mask = Image.new(im.size, '1') # black and white

    tran = im.getpixel((0,0))[0]   # transparent top-left

    for y in range(height):

        line = im.getpixel([(x, y) for x in range(width)])

        for x in range(width):

            if line[x] == tran:

                mask.point((x,y), 0)  # mask on the point

    return mask

An example usage



from graphics import Image



ship = Image.open('E:\\Images\\ship.gif')

mask = automask(ship)



canvas.blit(ship, mask=mask)  # don't forget to create canvas first

A Sprite class can be defined based on this too.

DZone Snippets: transparent code

PNG-24 Alpha support for IE

Using transparent gif/png with Image's blitting