Canvas API maintenance

[Richard Bair]

Looks good!

On May 18, 2012, at 12:10 PM, Jim Graham <james.graham at oracle.com> wrote:

> As was already mentioned, the existing (deprecated) methods on GraphicsContext for dealing with ImageData and writing pixels were preliminary and intended to be replaced by a mechanism that would be compatible with the FX Image Ops which were just reviewed and integrated.  To that end, I am proposing the following modification of the GraphicsContext API:
> 
> Remove deprecated methods, fields, and inner classes:
> 
> Remove Canvas.ImageData class
> Remove createImageData(...) factory methods // all variants
> Remove putImageData(...) // all variants
> 
> Add the following method:
> 
>    /**
>     * Returns a {@link PixelWriter} object that can be used to modify
>     * the pixels of the {@link Canvas} associated with this
>     * {@code GraphicsContext}.
>     * All coordinates in the {@code PixelWriter} methods on the returned
>     * object will be in device space since they refer directly to pixels.
>     *
>     * @return the {@code PixelWriter} for modifying the pixels of this
>     *         {@code Canvas}
>     */
>    public PixelWriter getPixelWriter();
> 
> Note that, just as it was in the draft of the Canvas API, there are no methods to get a PixelReader for the Canvas in this release.  Due to the asynchronous nature of our rendering threads it would require a bit of effort and documentation about blocking conditions to create such a mechanism.  We will try to implement that in an upcoming release, but in order to reduce the risk and simplify the implementation of this feature for this release, we are only providing similar pixel writing methods as were in the earlier API drafts...
> 
>            ...jim