On 02-Jun-20 8:34, Sergey Bylokhov wrote:
On 6/1/20 10:49 am, Alexander Zuev wrote:
I remember that at some point it was attempted to implement that
initially we draw the default image resolution(if the correct
resolution variant is not ready yet.) Not sure that it actually
works this way. If the current approach(when we try to draw the MRI
itself) does not work, should not we try to use default resolution
variant directly if the proper variant is not ready yet?
The problem here is that it really breaks logic of the drawImage as
intended by the documentation of the
java.awt.Graphics.drawImage(). Its JavaDoc clearly says that if
scaled image is not ready to be painted then
method should return false. That is exactly the case - as far as we
can tell at the first time we call the
drawHiDPIImage its observer reports image as not initialized yet. And
getting the standard resolution image
and scaling it might be problematic if the application started on the
display with magnification factor not equal to 1.
I think it is the reason we have for exception on the startup when
waitForImage() method in the test case is
commented out when we are starting on the 150% magnification factor
screen.
That specification knows nothing about MRI and all its references to
the "image"
are all about the main image which is passed to those methods. So to
follow the spec we
should always draw something if the main image/its default variant is
load already, we just
try to add an additional attempt to draw "better" resolution variant,
but if it is not ready
we should try to draw the main variant.
It also means that if a non-primary variant will never be loaded, we
still should be able to draw the default variant.
I think the current bug is a variation of
https://bugs.openjdk.java.net/browse/JDK-7183828
and we hit the same assertion using non-BufferedImage image, in our
case MRI.
That might be the case.
BTW I am not sure that it is related to JDK-8182043. The
FileSystemView/Win32ShellFolder2 create
the MRI on top of BufferedImages, which return its height/width
synchronously in the SunGraphics2D.drawHiDPIImage.
Well, right now the MRI in FileSystemView is never used for the reasons
i stated in the JDK-8182043
review - we never reach the code that initializes it.
The "Invalid Image variant" exception can occur only if ToolkitImage
is used(it is loaded via
Toolkit.getImage/createImage), this is probably the reason why the bug
is not reproduced easily.
