python image library making dotty gifs
sholden at holdenweb.com
Fri Jun 25 14:32:27 CEST 2004
Alex Hunsley wrote:
> Alex Hunsley wrote:
>> I'm using python image library 1.1.4
>> (http://www.pythonware.com/products/pil/) to plot images.
>> However, when I save an image to a gif file, it comes out very
>> dotty/ithered looking, even if it's a picture consisting only of one
>> Here's some example code that produces a dotty gif:
>> # pymand joy!
>> import Image
>> import ImageDraw
>> im = Image.new("RGB", (imageWidth, imageHeight))
>> draw = ImageDraw.Draw(im)
>> for y in range (0,imageHeight):
>> for x in range (0, imageWidth):
>> draw.point((x, y), (128,128,128))
>> # saving as a gif comes out dotty/dithered looking!
>> im.save("plotImage.gif", "GIF")
>> you can see the output gif here:
> sorry, duff link, should be .org.uk:
That's because PIL is storing the image as an indexed image, presumably
using a palette that doesn't contain your exact color, and hence the
software is dithering (that's a technical term, it doesn't mean the
program can't make it's mind up ;-) to approximate the color you asked for.
Try using a color from the web-safe palette (google for it) or better
still (even though the patents are now expired almost everywhere) use
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