Access to image contents on canvas - Mozilla

This is a discussion on Access to image contents on canvas - Mozilla ; Could someone tell me if it is possible to directly access (and therefore be able to change) the pixels of an image currently being displayed in an HTML page fr an extension? I have already worked out how to read ...

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Thread: Access to image contents on canvas

  1. Access to image contents on canvas

    Could someone tell me if it is possible to directly access (and
    therefore be able to change) the pixels of an image currently being
    displayed in an HTML page fr an extension? I have already worked out
    how to read the image myself and access the image content but this is
    effectively a copy of the original file and not its rendering onto
    Gecko's canvas. I would like to be able to change pixels currently
    being displayed to the user.

  2. Re: Access to image contents on canvas

    On Jul 20, 10:10*am, peterbayley wrote:
    > Could someone tell me if it is possible to directly access (and
    > therefore be able to change) the pixels of an image currently being
    > displayed in an HTML page fr an extension? *I have already worked out
    > how to read the image myself and access the image content but this is
    > effectively a copy of the original file and not its rendering onto
    > Gecko's canvas. *I would like to be able to change pixels currently
    > being displayed to the user.


    you can get the solution from here:
    http://www.pixastic.com/

  3. Re: Access to image contents on canvas

    On Jul 23, 10:15*pm, 茶*量* wrote:
    > On Jul 20, 10:10*am, peterbayley wrote:
    >
    > > Could someone tell me if it is possible to directly access (and
    > > therefore be able to change) the pixels of an image currently being
    > > displayed in an HTML page fr an extension? *I have already worked out
    > > how to read the image myself and access the image content but this is
    > > effectively a copy of the original file and not its rendering onto
    > > Gecko's canvas. *I would like to be able to change pixels currently
    > > being displayed to the user.

    >
    > you can get the solution from here:http://www.pixastic.com/


    Thanks for that - Very useful. I'm familiar with the Canvas tag and
    have used it for vector graphics although I haven't experimented with
    the image pixels as yet. It's not QUITE what I want as I need access
    to the actual image file (PNG etc) not just the rendered version on
    the canvas. But I already have access to teh binary image through the
    extension and I'm hoping I'll be able to access the image in the
    content document from the extension then use the canvas pixel drawing
    methods to change the image.

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