Could you review the updated fix:
http://cr.openjdk.java.net/~alexsch/8011059/webrev.08/
- Some related to the ToolkitImage staff is moved from SunToolkit
to ToolkitImageUtil
- MultiResolutionToolkitImage is moved from the LWCToolkit to
sun.awt.image package
- Preloading for the resolution variants is added
- Algorithm for the retrieving resolution variants in
g.drawImage() method is updated
- The test is updated
See more comments inline:
On 11/13/2013 11:28 PM, Jim Graham wrote:
Hi Alexander,
Please read my followup message on the wording for the SunHint
descriptions. The version you used in this webrev contains multiple
conflicting uses of the word "default".
The default value for the hint should be DEFAULT. Note that Mike has
already stated that NSImage uses @2x even on non-retina displays so it
is not clear that the default should be different depending on devScale.
The fix sets the resolution variant hint to default on Mac OS X
and to off for other platforms now.
Mike's latest response raises the question - if someone creates an
application with embedded @2x images, then they will get @2x on Macs
even if they have a non-retina display (if they use Cocoa). If we
follow the same principles here, then a developer developing a Java
app on a non-retina Mac would see the @2x images when they scale up
and might get the impression that the @2x images will be used on any
display with a transform, but the code to deal with them is only in
the Mac platform code. Should this support be more universal than that?
The logic for choosing the image scale is incorrect per my previous
email. You special case only TRANSLATESCALE which ignores cases where
the transform was "scaled down to identity" on a retina display (i.e.
those cases should not default to devScale), and ignores any transform
with any non-scale components (i.e. g.scale(100,100); g.rotate(.001);
will use the default resolution even though they scaled it up a lot).
The new logic uses the transform to get the destination image
width and height.
There is the trick question about the general transform type
because image sides are not equal after the transformation in this case.
So we could use only one side,
or maximum value from opposite sides or may be an average value.
The parameter passed to the getResVariant method is based on the
subimage size, but the method treats it as if it were based on the
full image size. Either compute the scaled size of the full image, or
inform the method of the sub-image being scaled, or simply pass in the
scales, otherwise you will get the default image for any sub-image
renderings of less than half of the original image even if they are
rendered at retina scales.
This is my fault. I really missed this part. It is updated in the fix.
The code in LWCToolkit.getImage() is not thread safe. You do lock
around the cache in the putImage() method, but you could end up
replacing the image twice with 2 different scalable versions of the
image since the code in LWCToolkit decided whether to make the image
outside of any synchronization.
Fixed.
The File/URL code in LWCToolkit is not protected by security
permission checks like the code in SunToolkit.
Fixed.
The fixes to LWCToolkit require a network connection for every image
created to see if the @2x version exists. Originally I thought that
would be an immense performance hit, but I see that a
url.openConnection() is done in SunToolkit to verify permissions. This
would, however, double the amount of network traffic for every image.
Also, I'm not sure if url.openConnection() is less overhead than the
openStream() method used in SunToolkit...?
The algorithm that gets the scaled image size is based on the width
and height of both images original and scaled. That means that both
images should be already preloaded.
In other case we need to draw the original image (because it is not
possible to know the destination image size) and wait for more
drawImage(Image ) calls to try to load the scaled image.
It seems that multi-resolution image preloading fixes image drawing
issue as well as issue with the image observers. An image observer is
not called from the g.drawImage()
method in case if both images images are preloded and the original
image does not have errors.
The fix does not use url.openConnection() now. It tries to preload
the @2x image and if it is successful it preloads the original image as
well.
I also look at the custom cursor part of the HiDPI issues. A user
needs to prepare the MultiResolutionImage and we can use
CImage.createFromImages(List<Image> images)
method to create necessary NSImage. This means that it should be
possible to obtain all resolution variants from the MultiResolutionImage.
I have included the "List<Image> getResolutionVariants()" method to
the MultiResolutionImage for that.
Thanks,
Alexandr.
...jim
On 11/13/13 8:11 AM, Alexander Scherbatiy wrote:
Could you review the updated fix:
http://cr.openjdk.java.net/~alexsch/8011059/webrev.07/
- The default sun hint is added.
However, it looks the same as the resolution variant ON hint right
now. It would better to leave the behavior on the non HiDPI displays the
same as it was before.
So the resolution variant hint is disabled by default for non
HiDPI displays.
- Resolution variant hints description is updated.
- The logic operator in the isHiDPIImage() method is formatted.
The @2x images are not preloaded in the LWCToolkit. It really can
cause image reloading after moving a window from a display from one
resolution to another.
However, it is not clear during the MultiResolutionImage creation
will the images be used on HiDPI displays or not.
May be there should be a flag that enables the high resolution
images preloading.
The original image can be replaced by the high resolution one in the
paint() method. It causes that the observer could get an image which is
different from the original one.
May be there is no any issue? If a MultiResolutionImage is not used
then all works as before. If a user implements MultiResolutionImage may
be he needs to have an information
about the actual drawn image in the observer even it is different
from the original.
Thanks,
Alexandr.
On 11/12/2013 11:43 PM, Jim Graham wrote:
Hi Alexander,
Some minor issues with this fix:
- All RenderingHints have a default setting where the system can
choose for you. The primary thing that the default settings allow is
for the answer to be based off of another hint. Often the QUALITY
hint provides the swing vote if an individual hint is left "DEFAULT".
That should probably also be the setting used for SG2D, and would
hinge off of the devScale, for example, as the deciding factor.
- Descriptions for "on" and "off" should be something like "Use
resolution variants of images" and "Use only default resolution
variants of images" (and "Default resolution variant usage"). Most of
the other descriptions on hints are statements of what is going to
happen or what is going to be used rather than a simple 'the X state
is Y'.
- It looks like the transform is used in SG2D to decide if the hiDPI
image should be used. I'm not familiar with the Mac's native use of
@2x, but I thought that they hinged the decision off of the "retina
scale" of the display, not off of the current transform. That way, if
you scale down an icon it doesn't change its look when it reaches .5x
scale (or .75x depending on the cutoff). Personally, I think it is
better to not use the transform to keep animations smooth, but I'm not
sure what Apple did.
- The logic in using the transform is also a bit murky. I think if
you set the scale on a retina display to exactly 1/2 it would use the
HiDPI version even though the scale was 1:1. Since I support not
examining the transform there, I'm going to present this as another
reason why we should just base it on devScale, but the logic could be
fixed if we really plan to use the transform here.
- The new logic in "isHiDPIImage()" is confusing because you line up
logic operations from 2 different levels of parentheses. I believe
that one version of our style guidelines included a rule that allowed
"indenting to parentheses level" and I would think that would be a
good rule to apply here. Or do something else to make the logic flow
there less tricky to read.
- Eventually we are going to need this support in more pipelines. I
believe that Win8 already has parameters that affect choices of
images, but they are only currently deployed on the Surface tablets
(i.e. there are no supported high DPI displays for desktop that I'm
aware of, but some of the Surface tablets ship with high DPI
screens). What would the impact be if we moved this into a more
general class in src/share? I suppose we might spend extra time
looking for variants of images that we don't need?
- Has any thought been given to the issues that someone raised with
cursors?
- Has any thought been given to my comments about MediaTracker and
image observer states for multi-res images? I don't see any attempt
here to preload the @2x image. The problem would probably only be
seen on multi-headed systems where one display is retina and one is
not - you would find the images suddenly reloading when you move the
window to the other screen and the application might not expect that
to happen. Which image is the Observer registered on? Since the
image is handed to the Observer, will an application be surprised when
their observer gets a handle to an image they've never seen? Is it an
issue if one of the "alternate resolution variant" images leaks into
an application's "hands" via the observer callbacks?
...jim
On 11/11/13 7:59 AM, Alexander Scherbatiy wrote:
Could you review the updated fix:
http://cr.openjdk.java.net/~alexsch/8011059/webrev.06/
Only internal API is exposed:
- MultiResolutionImage interface with method
"getResolutionVariant(int width, int height)" is added to the
com.sun.awt package
- Hints to switch on/off the resolution variant usage are added to
SunHints class
- Test is updated to use the MultiResolutionImage interface
Thanks,
Alexandr.
On 11/5/2013 3:16 PM, Alexander Scherbatiy wrote:
Thank you for the review.
Could you look at the updated fix:
http://cr.openjdk.java.net/~alexsch/8011059/webrev.05/
- URL is parsed to protocol, host, port, and path parts in the
LWCToolkit class.
I checked that URL(protocol, host, port, file) constructor
correctly handles -1 port value.
- Only last file name after last '/' in the URL path is converted
to @2x name
- Tests that check correct URL and path translation to @2x names
are
added to the ScalableImageTest
Thanks,
Alexandr.
On 11/1/2013 12:46 AM, Peter Levart wrote:
On 10/29/2013 05:45 PM, Alexander Scherbatiy wrote:
2. I'm not sure that the proposed getScaledImageName()
implementation in ScalableToolkitImage works perfectly for URLs
like this:
http://www.exampmle.com/dir/image
In this case it will try to find 2x image here:
http://www.exam...@2x.com/dir/image
which doesn't look correct.
Fixed. Only path part of a URL is converted to path2x.
Hi Alexander,
URLs like this:
http://www.example.com/dir.ext/image
will still be translated to:
http://www.example.com/d...@2x.ext/image
I think you need to search for last '.' after the last '/' in the
getScaledImageName();
Also the following code has some additional bugs:
853 static Image toScalableImage(Image image, URL url) {
854
855 if (url != null && !url.toString().contains("@2x")
856 && !(image instanceof
ScalableToolkitImage)) {
857 String protocol = url.getProtocol();
858 String host = url.getHost();
859 String file = url.getPath();
860 String file2x =*host
+*getScaledImageName(file);
861 try {
862 URL url2x = new URL(protocol, host,
file2x);
863 url2x.openStream();
864 return new ScalableToolkitImage(image,
getDefaultToolkit().getImage(url2x));
865 } catch (Exception ignore) {
866 }
867 }
868 return image;
869 }
Why are you prepending *host* to getScaledImageName(file) in line
860? Let's take the following URL for example:
http://www.example.com/dir/image.jpg
protocol = "http"
host = "www.example.com"
file = "/dir/image.jpg"
file2x = "*www.example.com*/dir/im...@2x.jpg"
url2x =
URL("http://www.example.com*www.example.com*/dir/im...@2x.jpg";)
You are missing a part in URL (de)construction - the optional port!
For example in the following URL:
http://www.example.com:8080/dir/image.jpg
You should extract the port from original URL and use it in new URL
construction if present (!= -1).
I would also close the stream explicitly after probing for existence
of resource rather than delegating to GC which might not be promptly
and can cause resource exhaustion (think of MAX. # of open file
descriptors):
try (InputStream probe = url.openStream()) {}
Regards, Peter
![http://www.example.com*www.example.com*/dir/im...@2x.jpg"](http://www.example.com*www.example.com*/dir/im...@2x.jpg"){kind=link}
