Hi Sergey,
On 11/6/13 5:20 PM, Sergey Bylokhov wrote:
On 07.11.2013 4:09, Jim Graham wrote:
On 11/6/13 3:09 PM, Sergey Bylokhov wrote:
That method "returns a scaled version of *this* image". It
specifically refers to recombining the pixels of the image you would
normally get into a new image that, by default, renders at the
requested size.
The method has parameters to control the pixel replication/elimination
*algorithm*.
Custom hint can be renamed to the BEST_EVER_QUALITY_AS_IMAGE_CANhint and
write in doc that it is nop by default..
No hint can be a nop because the returned image *MUST* render at the
requested size when passed to drawImage(img, x, y).
All of the hints refer to pixel resampling algorithms, there is no
history of the hints or that method ever doing anything but pixel
resampling. Any ambiguity was left in order to support other pixel
resampling algorithms in the future and for no other reason.
drawImage() should *NOT* be using this method on its own, and the
method should not be involved in choosing alternate designs. It is
for manually resampling an image into a new permanent image.
Why not? We can document that. It is something related to
|RenderingHints.KEY_INTERPOLATION| which was added as an alternate of
image hints. But this new hints do not provide possibility to customize
scaling by the user.
Because it never has. Because it's operation is specified to be
asynchronous and so drawImage cannot depend on being able to produce a
result if it uses that method. Because it was created to solve a
different purpose that has nothing to do with on-the-fly source image
replacement. Because developers have been free to create their own
implementations that could do any number of things that would be
inappropriate inside a drawImage call. Because you've already
discovered that, in fact, the default implementation was never anything
that should ever be done inside a drawImage and you think that providing
a workaround for that single issue is the answer rather than the fact
that it should have been a huge wake up call that you barked up the
wrong tree.
Fact: getScaledInstance() *MUST ALWAYS* return an image that is the
requested WxH. It has no other option. you can't override that *API
REQUIREMENT* in the documentation of a hint. Read the documentation
for it: "A new Image object is returned which will render the image at
the specified width and height by default."
Yes, I see. The image should be "new" and it does not say it should be
the same object. And content of this "new" image depends from the hint
which was passed to the method.
And, the image must be the indicated WxH - not a different WxH that
might be somehow compatible with a request to draw at the requested WxH,
but getWidth() and getHeight() *MUST* return the indicated parameters
and if you render it with no w,h specified in the drawImage() call then
it *MUST* draw at the indicated dimensions.
You are not understanding that it is a new scaled version of *THIS*
image. The pixels from the original image must be used. This is about
pixel replication algorithms, not about redesigning a representation.
The user know what pixels contains in its image, and he know how to
scale its better.
But, the spec of the method is specifically geared towards pixel
resampling, not pixel re-authoring.
...jim
