On 27.11.2013 15:12, Sergey Bylokhov wrote:
Hello.
Probably we are in a point when it is necessary to stop and move out
all extensions to the separate bugs.
We should give a time to our sqe to test these changes.
Actually current version looks good to me.
Small additional notes, It would be good:
- to wrap initial observer in the drawImage and replace img/x,y,....
in the observer.
- don't draw hidpi image, if it was loaded with errors.
- sun.com package should be used?
- If MediaTracker was requested to load MultiResolutionImage,it should
load all versions?
On 26.11.2013 2:31, Jim Graham wrote:
On 11/25/13 5:51 AM, Alexander Scherbatiy wrote:
On 11/23/2013 5:11 AM, Jim Graham wrote:
Hi Alexander,
If we are going to be advertising it as something that developers use
in production code then we would need to file this via CCC. With the
current implementation, any user that has their own ImageObservers
must use this API and so it becomes not only public, at a time when
there is a lockdown on new public API in 8.0, but it also means that
we are tied to its implementation and we can't rely on "it was
experimental and so we can change it at any point" - you can't say
that about an API that is necessary to correctly use a touted feature.
This issue has its own history. It has been already fixed for the
JDK 7u for the Java2D demo. It was decided to not bring new API for the
HiDPI support in the JDK 7.
It was suggested to using code like below to create a
ScalableImage.
------------------------------
/**
* Class that loads and returns images according to
* scale factor of graphic device
*
* <pre> {@code
* Image image = new ScalableImage() {
*
* public Image createScaledImage(float scaleFactor) {
* return (scaleFactor <= 1) ? loadImage("image.png")
* : loadImage("im...@2x.png");
* }
*
* Image loadImage(String name){
* // load image
* }
* };}</pre>
*/
------------------------------
It was based on the display scale factor. The scale factor should be
manually retrieved from the Graphics2D and was not a part of the public
API:
g2d.drawImage(scalbleImage.getScaledImage(scaleFactor),..).
From that time it was clear that there should be 2 basic operations
for the HiDPI images support:
- retrieve an image with necessary resolution
- retrieve images with all resolutions
The second one is useful when it is necessary to create one set of
images using the given one (for example, to draw a shape on all
images).
For now, these are just ToolkitImages and you can't draw on them, so
this is moot for the case of @2x support in getImage().
The JDK 7 solution has been revisited for the JDK 8 and the
neccesary
CCC request 8011059 has been created and approved.
Both the JDK-8011059 issue description and the approved CCC request
says:
-----------------------
A user should have a unified way to provide high resolution images
that can be drawn on HIDPI displays according to the user provided
algorithm.
-----------------------
We've implemented the Hint part of that solution, but the mechanism
for creating custom multi-res images was not workable. I no longer
sit as the client rep on the CCC or I would have pointed that out, my
apologies.
The 8011059 fix consists of two parts:
- Provide a way for a custom image creation that holds images with
different resolutions
- Load @2x images on Mac OS X
The first one of the fix can be used without the second. it is not
difficult to crate just a class which loads @2x images using the given
file path/url.
If we support @2x transparently behind the scenes as we are doing
now, who is the requester for the way to create a custom set of
resolution variants? I think the most important customer-driven
request was to support @2x for the Mac developers, wasn't it?
Now it is suggested to implement the given MultiResolutionImage
interface and override two methods:
- Image getResolutionVariant(int width, int height)
- List<Image> getResolutionVariants()
An image with necessary resolution should be drawn automatically in
SunGraphics2D.
What we need is to focus on the first part of the fix.
From this point of view it up to the user' code to load all or some
resolution variants by MediaTracker and using
Component.prepareImage/checkImage methods.
This is all an interesting goal, but I'm not sure it is as high a
priority if we support a convention (based on platform conventions)
for high resolution variants behind the scenes. I do agree that we
need something like this before too long, but I don't think it was
workable to target the getScaledInstance() method as the mechanism to
implement it. That was the only convention that was approved in that
CCC request, so a more complete API based on another mechanism is not
covered there.
Also, Win8 has its own conventions as well which come into play on
the new high resolution Surface tablets and we should consider those
to guide the API we develop.
All, in all, though, I think if we get @2x support in with no code
changes needed for apps then we have taken care of the primary use
case. We can probably even handle the Win8 conventions behind the
scenes in an 8u release...
...jim
--
Best regards, Sergey.
