Talk:How to display transparent PNG on canvas with masks
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Level: Expert
Portable Network Graphics (PNG) is a bitmapped image format that employs lossless data compression. PNG was designed for transferring images on the Internet, not for professional graphics. PNG offers a variety of transparency options. With truecolor and greyscale images either a single pixel value can be declared as transparent or an alpha channel can be added. One of the basic concept for PNG is described in this article "Displaying PNG on Canvas".
Basically, PyS60 is unable to producing images with alpha information (32-bit), however there is a method to show transparent PNG images using the mask parameter.
The author, Javsmo, has used very cool clock using Inkscape which has a transparent background that is exported to PNG. The author has used a mask parameter to help graphics, to know where the transparent pixels are on the image. The automask function is used to automatically create an image mask from another image.
Finally, the image is perfectly merged with gradient background and looks more presentable as shown in the last screenshot in the article.
Nirpsis 18:55, 4 September 2009 (UTC)
