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List: openjdk-2d-dev
Subject: Re: [OpenJDK 2D-Dev] <AWT Dev> [9] Review request for 8029339 Custom MultiResolution image support o
From: Alexander Scherbatiy <alexandr.scherbatiy () oracle ! com>
Date: 2014-03-27 14:43:32
Message-ID: 53343914.6090004 () oracle ! com
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Below are some thoughts about TK.createMRImage(...) method
On 3/24/2014 4:52 PM, Alexander Scherbatiy wrote:
> Hello,
>
> Could you review the updated fix:
> http://cr.openjdk.java.net/~alexsch/8029339/webrev.03/
>
> - baseImageWidth/Height arguments are added to the
> getResolutionVariant(...) method
> - dest image sizes are reverted to included DPI scale
> - AbstractMultiResolutionImage is added. It needs only to implement
> only 3 methods from the AbstractMultiResolutionImage class
> to create a custom multi-resolution image. For example:
>
> On 3/22/2014 3:57 AM, Jim Graham wrote:
> >
> > Your code example below can be expressed as an implementation of the
> > single-method, lambda-compatible interface that expresses just the
> > getRV() method. They could easily do:
> >
> > final Image baseImage = ...;
> > TK.createMRImage(new RVInterface() {
> > public Image getRV(...) {
> > // calculate rvWidth and rvHeight
> > // look up rvWidth/rvHeight in a database of images
> > // possibly contruct a new image
> > return rvImage;
> > }
> > }, baseImage);
> >
The RVInterface mixes the logic that construct an image and
chooses the necessary resolution variant.
It is ok if a developer always implements this interface. If it
needs to have DPI/Transform/Platform aware RVInterface the image
construction logic should be separated.
Does TK.createMRImage() method implies that Platform aware logic
should be used for a resolution-variant choosing?
If so, may be general createMRImage() can be placed in the
ImageResolutionHelper.
> > The main issue I see is if you might want the newly constructed
> > variants to appear in the List returned from the getVariants()
> > method. I'm not sure what value that would have beyond simply
> > returning the base media that the object uses from which to construct
> > its variants...?
It can be solved by using something like array of image sizes or
other seeds and a mapper that can create an image from the given seed.
It can look like:
-------------------------
public class ImageResolutionHelper {
public interface RVChooser {
public Image getRV(
float logicalDPIX, float logicalDPIY,
float baseImageWidth, float baseImageHeight,
float destImageWidth, float destImageHeight,
final Image... resolutionVariants);
}
public static final RVChooser DPI_AWARE = ...;
public static final RVChooser TRANSFORM_AWARE = ...;
// resolutionVariants is an array of sorted by width/height images
static Image createMRImage(final RVChooser rvChooser,
final int baseImageIndex, final Image...
resolutionVariants) { ... }
// sorted by width/height images should be generated from seeds
static <Type> Image createMRImage(final RVChooser rvChooser,
final Type baseImageSeed, final Function<Type, Image>
mapper, final Type... rvSeeds) {...}
}
public abstract class Toolkit {
public abstract Image createMRImage(int baseImageIndex, Image...
resolutionVariants); // Platform aware rv chooser is used
public abstract RVChooser getPlatformRVChooser() ;
}
--------------------------
Thanks,
Alexandr.
> >
> > > I think it is better to provide both the MultiResolutionImage and
> > > its implementation based on the given resolution variants array.
> >
> > It occurs to me that even if we don't go with a lambda-factory-based
> > approach like what I'm describing, it might make sense to provide a
> > baseMR implementation that they can subclass to keep them from trying
> > to subclass off of BufferedImage instead. I really would like to
> > avoid "custom MR images are subclasses of BufImg" if we can as I
> > think the mix of concepts is a little jarring...
> >
> > ...jim
> >
> > > The implementation could look like:
> > > ---------------------------------
> > > public class CustomMultiResolutionImage extends Image implements
> > > MultiResolutionImage {
> > >
> > > int baseImageIndex;
> > > Image[] resolutionVariants;
> > >
> > > public CustomMultiResolutionImage(int baseImageIndex,
> > > Image... resolutionVariants) {
> > > this.baseImageIndex = baseImageIndex;
> > > this.resolutionVariants = resolutionVariants;
> > > }
> > >
> > > @Override
> > > public int getWidth(ImageObserver observer) {
> > > return getBaseImage().getWidth(null);
> > > }
> > >
> > > @Override
> > > public int getHeight(ImageObserver observer) {
> > > return getBaseImage().getHeight(null);
> > > }
> > >
> > > @Override
> > > public ImageProducer getSource() {
> > > return getBaseImage().getSource();
> > > }
> > >
> > > @Override
> > > public Graphics getGraphics() {
> > > return getBaseImage().getGraphics();
> > > }
> > >
> > > @Override
> > > public Object getProperty(String name, ImageObserver observer) {
> > > return getBaseImage().getProperty(name, observer);
> > > }
> > >
> > > @Override
> > > public Image getResolutionVariant(float logicalDPIX, float
> > > logicalDPIY,
> > > float destinationImageWidth, float
> > > destinationImageHeight) {
> > > // calculate resolution variant width/height
> > > return getResolutionVariant(rvWidth, rvHeight);
> > > }
> > >
> > > @Override
> > > public List<Image> getResolutionVariants() {
> > > return Arrays.asList(resolutionVariants);
> > > }
> > >
> > > private Image getResolutionVariant(float rvWidth, float
> > > rvHeight) {
> > > // return a resolution variant based on the given width and
> > > height
> > > }
> > >
> > > private Image getBaseImage() {
> > > return resolutionVariants[baseImageIndex];
> > > }
> > > }
> > > ---------------------------------
> > >
> > > Thanks,
> > > Alexandr.
> > >
> > > >
> > > > Then we provide one of these from TK.get/createImage() when the
> > > > platform detects @2x, or Win8-style variants.
> > > >
> > > > For custom images we provide TK.createMRImage(lambda getRV, Image
> > > > variants...) and TK.createMRImage(Image variants...);
> > > >
> > > > Since the get<List> method is just bookkeeping, I don't see them
> > > > needing to override it, so the getRV() method is really the only thing
> > > > they might want to override, and we can tie into the new Lambda
> > > > capabilities by making a single-method interface for it that they
> > > > supply in a factory method.
> > > >
> > > > I realize that the interface you created is more fundamentally OO, but
> > > > the Image class has always been special in this regard in the AWT
> > > > ecosystem (in so far as we do not support someone implementing their
> > > > own Image subclass even though it is technically possible). Because of
> > > > this special nature of Image, we end up with the situation that if
> > > > someone were given a need to create a subclass of Image, then they
> > > > would turn to BufImg as their superclass even though BufImg is
> > > > essentially an implementation-specific leaf node on the Image class
> > > > hierarchy. This approach with a factory method to create an internal
> > > > subclass of the new MRI class mirrors the existing cases of Image
> > > > objects that come from factories as well.
> > > >
> > > > Thoughts?
> > > >
> > > > ...jim
> > > >
> > > >
> > > > On 3/20/14 7:52 AM, Alexander Scherbatiy wrote:
> > > > >
> > > > > Hello,
> > > > >
> > > > > Could you review the updated version of the fix:
> > > > > http://cr.openjdk.java.net/~alexsch/8029339/webrev.01/
> > > > >
> > > > > - The "getResolutionVariant(int width, int height)" method from
> > > > > MultiResolutionImage class is changed to
> > > > > Image getResolutionVariant(float logicalDPIX, float logicalDPIY,
> > > > > float width, float height, AffineTransform transform);
> > > > >
> > > > > - sun.awt.image.ImageResolutionHelper class is added. The
> > > > > sun.awt.image.MultiResolutionToolkitImage and
> > > > > sun.awt.image.MultiResolutionBufferedImage classes are used
> > > > > PLATFORM ImageResolutionHelper.
> > > > >
> > > > > The MultiResolutionImage interface implementation could look like:
> > > > > ------------------------------
> > > > > public class CustomMultiResolutionImage extends BufferedImage
> > > > > implements
> > > > > MultiResolutionImage {
> > > > >
> > > > > private final Image[] resolutionVariants;
> > > > >
> > > > > public CustomMultiResolutionImage(int baseIndex, Image...
> > > > > images) {
> > > > > super(images[baseIndex].getWidth(null),
> > > > > images[baseIndex].getHeight(null),
> > > > > BufferedImage.TYPE_INT_RGB);
> > > > > this.resolutionVariants = images;
> > > > > Graphics g = getGraphics();
> > > > > g.drawImage(images[baseIndex], 0, 0, null);
> > > > > g.dispose();
> > > > > }
> > > > >
> > > > > @Override
> > > > > public Image getResolutionVariant(float logicalDPIX, float
> > > > > logicalDPIY,
> > > > > float width, float height, AffineTransform transform) {
> > > > > return getResolutionVariant(logicalDPIX * width,
> > > > > logicalDPIY *
> > > > > height);
> > > > > }
> > > > >
> > > > > @Override
> > > > > public List<Image> getResolutionVariants() {
> > > > > return Arrays.asList(resolutionVariants);
> > > > > }
> > > > >
> > > > > public Image getResolutionVariant(double width, double height) {
> > > > > for (Image image : resolutionVariants) {
> > > > > if (width <= image.getWidth(null) && height <=
> > > > > image.getHeight(null)) {
> > > > > return image;
> > > > > }
> > > > > }
> > > > > return this;
> > > > > }
> > > > > }
> > > > > ------------------------------
> > > > >
> > > > >
> > > > > Thanks,
> > > > > Alexandr.
> > > > >
> > > > > On 2/27/2014 4:54 PM, Alexander Scherbatiy wrote:
> > > > > > On 2/22/2014 3:54 AM, Jim Graham wrote:
> > > > > > > Hi Alexandr,
> > > > > > >
> > > > > > > On 2/18/14 7:33 AM, Alexander Scherbatiy wrote:
> > > > > > > > Hi Jim,
> > > > > > > >
> > > > > > > > Let's divide the discussion into two part.
> > > > > > > >
> > > > > > > > 1. Where it is better to hold resolution variants?
> > > > > > > > Putting resolution variants in Image class brings some
> > > > > > > > questions like:
> > > > > > > > - Some type of images do not need to have resolution variants
> > > > > > > > - Should resolution variants have the same type as the base
> > > > > > > > image?
> > > > > > > > - getResolutionVariants() method can return copy of the
> > > > > > > > original
> > > > > > > > list
> > > > > > > > so add/removeRV methods should be also added.
> > > > > > > >
> > > > > > > > There are pros and cons for placing resolution variants to
> > > > > > > > Image
> > > > > > > > class or to a separate intreface.
> > > > > > >
> > > > > > > I agree that this could be a separate interface. In my examples
> > > > > > > below I was just sticking them inside an "Image{}" to show where
> > > > > > > they
> > > > > > > lived in the set of involved objects, not a specific recommendation
> > > > > > > that they actually be new methods on the base class itself. I
> > > > > > > probably should have put a comment there about that.
> > > > > > >
> > > > > > > With respect to add/remove - that is assuming a need for manual
> > > > > > > construction of an image set, right? Forgive me if I'm forgetting
> > > > > > > something, but I seem to recall that manual Multi-Res images was
> > > > > > > proposed as a way for developers to introduce @2x support
> > > > > > > themselves,
> > > > > > > but if we are internally managing @2x and -DPI variants for them,
> > > > > > > then I'm not sure if there is actual developer need to manually
> > > > > > > construct their own. Am I forgetting something?
> > > > > > The NSImage has addRepresentation/removeRepresentation methods to
> > > > > > work with image representations on Mac OS X.
> > > > > > The java.awt.Image class should provide similar functionality to
> > > > > > have the possibilities as Cocoa on HiDPI displays.
> > > > > >
> > > > > > >
> > > > > > > > 2. Using scale factor/image sizes/scaled image sizes to
> > > > > > > > retreive a
> > > > > > > > resolution variant.
> > > > > > > >
> > > > > > > > May be it is better to have a structure that provide all
> > > > > > > > necessary
> > > > > > > > information to query the resolution variant: scale factor,
> > > > > > > > draw area
> > > > > > > > width/height, transformed area width/height?
> > > > > > > >
> > > > > > > > For example:
> > > > > > > > ---------------------
> > > > > > > > public interface MultiResolutionImage {
> > > > > > > >
> > > > > > > > interface DrawAreaInfo {
> > > > > > > >
> > > > > > > > float getScaleFactor();
> > > > > > > > float getAreaWidth();
> > > > > > > > float getAreaHeight();
> > > > > > > > float getTransformedAreaWidth();
> > > > > > > > float getTransformedAreaHeight();
> > > > > > > > }
> > > > > > > >
> > > > > > > > public Image getResolutionVariant(DrawAreaInfo
> > > > > > > > drawAreaInfo) ;
> > > > > > > > public List<Image> getResolutionVariants();
> > > > > > > > }
> > > > > > > > ---------------------
> > > > > > >
> > > > > > > The problem with a constructor is that this is something that is
> > > > > > > (potentially) done on every drawImage() call, which means we are
> > > > > > > inviting GC into the equation. If we can come up with a simple
> > > > > > > "just
> > > > > > > a couple/3/4 numbers" way to embed that data into a method call
> > > > > > > argument list then we can make this lighter weight.
> > > > > > >
> > > > > > > What about simply having floating point (double) dimensions on the
> > > > > > > rendered size
> > > > > > There should be a way to choose a resolution variant based on
> > > > > > requested drawing size or transformed drawing size.
> > > > > > At least a current transformation should be included too.
> > > > > > > plus a single floating point "logical DPI" for the screen?
> > > > > > There is the ID2D1Factory::GetDesktopDpi method which returns
> > > > > > dpiX and dpiY.
> > > > > > http://msdn.microsoft.com/en-us/library/windows/apps/dd371316
> > > > > >
> > > > > > That means that logicalDPIX/Y can have different values.
> > > > > > At least it is described in the
> > > > > > http://msdn.microsoft.com/en-us/library/windows/apps/ff684173
> > > > > > "To get the DPI setting, call the ID2D1Factory::GetDesktopDpi
> > > > > > method. The DPI is returned as two floating-point values, one for
> > > > > > the
> > > > > > x-axis and one for the y-axis. In theory, these values can differ.
> > > > > > Calculate a separate scaling factor for each axis."
> > > > > >
> > > > > > The getResolutionVariant method could look like:
> > > > > > --------------------------------------
> > > > > > public Image getResolutionVariant(float logicalDPIX, float
> > > > > > logicalDPIY,
> > > > > > float widthX, float widthY, AffineTransform transform);
> > > > > > --------------------------------------
> > > > > >
> > > > > > > If the image is known (either passed as an argument or the
> > > > > > > method is
> > > > > > > called on the image), then it can provide the original WH.
> > > > > > >
> > > > > > > > The MultiResolutionImage default implementation could allow
> > > > > > > > to use
> > > > > > > > different strategies like scale factor/transfom/OS based
> > > > > > > > to query a resolution variant. The OS based strategy can be
> > > > > > > > used by
> > > > > > > > default.
> > > > > > >
> > > > > > > For Mac policy, all we need is the transformed dimensions, which
> > > > > > > can
> > > > > > > be passed in as FP for generality. For Windows policy, all we need
> > > > > > > is logical DPI for the screen. What other information would we
> > > > > > > need, or would an algorithm like to use, that can't be computed
> > > > > > > from
> > > > > > > those 2 pieces?
> > > > > > The aim is to provide a base class that can be used to create a
> > > > > > MultiResolutionImage like:
> > > > > > http://hg.openjdk.java.net/jdk9/client/jdk/diff/ae53ebce5fa3/src/share/classes/sun/awt/image/MultiResolutionBufferedImage.java \
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > > A developer should be able to implement a custom algorithm to
> > > > > > query a resolution variant.
> > > > > >
> > > > > > It can be done by overriding the getResolutionVariant image:
> > > > > > -----------------------
> > > > > > Image mrImage = new MultiResolutionBufferedImage(){
> > > > > > @Override
> > > > > > public Image getResolutionVariant(...) {
> > > > > > // Custom logic here
> > > > > > }
> > > > > > };
> > > > > > -----------------------
> > > > > >
> > > > > > Or it can be done by using resolution variant choosers so a
> > > > > > developer can implement custom resolution variant query:
> > > > > > -----------------------
> > > > > > public class MultiResolutionBufferedImage implements
> > > > > > MultiResolutionImage{
> > > > > >
> > > > > > interface ResolutionVariantChooser{
> > > > > > Image getResolutionVariant(dpi, size,..., List<Image>
> > > > > > resolutionVariants);
> > > > > > }
> > > > > > ResolutionVariantChooser TRANSFORM_BASED = null;
> > > > > > ResolutionVariantChooser DPI_BASED = null;
> > > > > >
> > > > > > ResolutionVariantChooser rvChooser;
> > > > > >
> > > > > > @Override
> > > > > > public Image getResolutionVariant(dpi, size,...,) {
> > > > > > return rvChooser.getResolutionVariant(dpi, size,...,
> > > > > > getResolutionVariants());
> > > > > > }
> > > > > > }
> > > > > > -----------------------
> > > > > >
> > > > > > Thanks,
> > > > > > Alexandr.
> > > > > >
> > > > > > >
> > > > > > > ...jim
> > > > > > >
> > > > > > > > Thanks,
> > > > > > > > Alexandr.
> > > > > > > >
> > > > > > > >
> > > > > > > > On 2/13/2014 4:42 AM, Jim Graham wrote:
> > > > > > > > > On 2/12/14 5:59 AM, Alexander Scherbatiy wrote:
> > > > > > > > > > On 2/8/2014 4:19 AM, Jim Graham wrote:
> > > > > > > > > > > The primary thing that I was concerned about was the
> > > > > > > > > > > presence of
> > > > > > > > > > > integers in the API when Windows uses non-integer multiples
> > > > > > > > > > It would make sense to pass real numbers to the
> > > > > > > > > > getResolutionVariant() method if the difference between
> > > > > > > > > > resolution
> > > > > > > > > > variants sizes is 1.
> > > > > > > > > > It seems that it is not a common case.
> > > > > > > > >
> > > > > > > > > I was thinking of other API that is related to this, such as
> > > > > > > > > the API
> > > > > > > > > that queries the scaling factor from a SurfaceManager. I seem to
> > > > > > > > > remember some integer return values in that, but Windows might
> > > > > > > > > have
> > > > > > > > > the answer 1.4 or 1.8, depending on the screen scaling factor
> > > > > > > > > that was
> > > > > > > > > determined from the UI.
> > > > > > > > >
> > > > > > > > > In terms of the getResolutionVariant() method here, those
> > > > > > > > > non-integer
> > > > > > > > > screen scaling factors don't directly impact this API. But, we
> > > > > > > > > have
> > > > > > > > > some issues with the use of integers there from other sources:
> > > > > > > > >
> > > > > > > > > - That API assumes that the caller will determine the pixel size
> > > > > > > > > needed, but the actual media choice is determined with different
> > > > > > > > > techniques on Mac and Windows so this means that the caller will
> > > > > > > > > have
> > > > > > > > > to worry about platform conventions. Is that the right tradeoff?
> > > > > > > > >
> > > > > > > > > - The technique recommended for Mac involves computing the
> > > > > > > > > precise
> > > > > > > > > size desired using the current transform, which may be a floating
> > > > > > > > > point value, so the integer values used in this API are already
> > > > > > > > > approximations and there is no documentation on how to
> > > > > > > > > generate the
> > > > > > > > > proper integer. In particular, the current code in SG2D naively
> > > > > > > > > uses
> > > > > > > > > a cast to integer to determine the values to supply which means a
> > > > > > > > > transformed size of W+0.5 will be truncated to W and the lower
> > > > > > > > > resolution image will be used. Does that conform to Mac
> > > > > > > > > guidelines? Do
> > > > > > > > > they require the truncated size to reach W+1 before the next
> > > > > > > > > size is
> > > > > > > > > used? Passing in float or double values would sidestep all of
> > > > > > > > > that
> > > > > > > > > since then the comparisons would be done with full precision,
> > > > > > > > > but as
> > > > > > > > > long as we can determine a "best practices compatible with all
> > > > > > > > > platforms" rule on how to round to integers, then integers are OK
> > > > > > > > > there.
> > > > > > > > >
> > > > > > > > > - The Windows document you cite below suggests that the
> > > > > > > > > determination
> > > > > > > > > should be made by looking at the Screen DPI and choosing the next
> > > > > > > > > higher media variant based on that screen DPI. They do not
> > > > > > > > > specify
> > > > > > > > > choosing media based on the current transform as is done for
> > > > > > > > > Mac. If
> > > > > > > > > we stick with supplying values that are used to determine which
> > > > > > > > > media
> > > > > > > > > to use, then on Windows we should not take the transform into
> > > > > > > > > account,
> > > > > > > > > but instead query the SurfaceManager for the scale factor and
> > > > > > > > > only
> > > > > > > > > transform by those values (even if the current transform was
> > > > > > > > > manually
> > > > > > > > > overridden to identity).
> > > > > > > > >
> > > > > > > > > There are pros and cons to both approaches.
> > > > > > > > >
> > > > > > > > > Mac ensures that you are always using the best media for any
> > > > > > > > > given
> > > > > > > > > render operation.
> > > > > > > > >
> > > > > > > > > But, Windows ensure more consistency in the face of other
> > > > > > > > > scaling.
> > > > > > > > >
> > > > > > > > > The thing to consider is that if you have a 500x500 image with a
> > > > > > > > > 1000x1000 variant and you rendering it at 500x500 and then
> > > > > > > > > 501x501,
> > > > > > > > > that first jump will be fairly jarring as the scaled version
> > > > > > > > > of the
> > > > > > > > > 1000x1000 will not look precisely like the original 500x500 did.
> > > > > > > > > With
> > > > > > > > > @2x images only, this effect is minimized so the advantage of
> > > > > > > > > always
> > > > > > > > > using "the best media for a given render operation" may
> > > > > > > > > outweigh the
> > > > > > > > > inconsistency issue. But, on Windows where the media are 1.4x or
> > > > > > > > > 1.8x
> > > > > > > > > in size, a downscaled image will start to show more interpolation
> > > > > > > > > noise and so the balance of the two choices may shift more
> > > > > > > > > towards not
> > > > > > > > > wanting a jarring shift.
> > > > > > > > >
> > > > > > > > > We might want one or more of the following:
> > > > > > > > >
> > > > > > > > > - Developer chooses policy (TX_AWARE, DPI_AWARE, ALWAYS_LARGEST,
> > > > > > > > > NONE,
> > > > > > > > > PLATFORM) where the last policy would use TX_AWARE on Mac and
> > > > > > > > > DPI_AWARE on Windows
> > > > > > > > >
> > > > > > > > > - We create our own policy and always use it (TX_AWARE? or
> > > > > > > > > DPI_AWARE?)
> > > > > > > > >
> > > > > > > > > - We create our own policy that dynamically chooses one of the
> > > > > > > > > above
> > > > > > > > > strategies depending on platform or available media or ???
> > > > > > > > >
> > > > > > > > > - We could create an optional interface for them to install their
> > > > > > > > > own
> > > > > > > > > algorithm as well. I think it would work best as a delegate
> > > > > > > > > interface
> > > > > > > > > that one installs into Image so that it can be used with any
> > > > > > > > > image
> > > > > > > > > without having to subclass (it wouldn't really have much to do
> > > > > > > > > for
> > > > > > > > > BufferedImages or VolatileImages, though):
> > > > > > > > >
> > > > > > > > > class Image {
> > > > > > > > > void setResolutionHelper(ImageResolutionHelper foo);
> > > > > > > > > List<Image> getResolutionVariants();
> > > > > > > > > }
> > > > > > > > >
> > > > > > > > > or:
> > > > > > > > >
> > > > > > > > > class Graphics {
> > > > > > > > > void setResolutionHelper(ImageResolutionHelper foo);
> > > > > > > > > }
> > > > > > > > >
> > > > > > > > > or - anywhere else it could be installed more centrally (per App
> > > > > > > > > context)?
> > > > > > > > >
> > > > > > > > > and the interface would be something like one of these variants:
> > > > > > > > >
> > > > > > > > > interface ImageResolutionHelper {
> > > > > > > > > // This version would prevent substituting a random image:
> > > > > > > > > // They have to return an index into the List<Image> for that
> > > > > > > > > image...
> > > > > > > > > public int chooseVariant(Image img, double dpi, number w,
> > > > > > > > > number h);
> > > > > > > > >
> > > > > > > > > or:
> > > > > > > > >
> > > > > > > > > // This version would allow substituting an arbitrary image:
> > > > > > > > > public Image getVariant(Image img, double dpi, number w,
> > > > > > > > > number
> > > > > > > > > h);
> > > > > > > > > }
> > > > > > > > >
> > > > > > > > > Since they would be in full control of the policy, though, we
> > > > > > > > > would
> > > > > > > > > unfortunately always have to call this, there would be no more
> > > > > > > > > testing
> > > > > > > > > in SG2D to see "if" we need to deal with DPI, though perhaps we
> > > > > > > > > could
> > > > > > > > > document some internal conditions in which we do not call it for
> > > > > > > > > common cases (but that would have to be well agreed not to get in
> > > > > > > > > the
> > > > > > > > > way of reasonable uses of the API and well documented)?
> > > > > > > > >
> > > > > > > > > Note that we would have to do a security audit to make sure that
> > > > > > > > > random image substitution couldn't allow any sort of "screen
> > > > > > > > > phishing"
> > > > > > > > > exploit.
> > > > > > > > >
> > > > > > > > > ...jim
> > > > > > > > >
> > > > > > > > > > > and also what policy they use for choosing scaled images.
> > > > > > > > > > >
> > > > > > > > > > > I don't see a mention of taking the current transform into
> > > > > > > > > > > account,
> > > > > > > > > > > just physical issues like screen DPI and form factor. They talk
> > > > > > > > > > > about
> > > > > > > > > > > resolution plateaus and in their recommendations section they
> > > > > > > > > > > tell the
> > > > > > > > > > > developer to use a particular property that tells them the
> > > > > > > > > > > screen
> > > > > > > > > > > resolution to figure out which image to load if they are
> > > > > > > > > > > loading
> > > > > > > > > > > manually. There is no discussion about dynamically loading
> > > > > > > > > > > multiple
> > > > > > > > > > > versions of the image based on a dynamic program-applied
> > > > > > > > > > > transform
> > > > > > > > > > > factor as is done on MacOS.
> > > > > > > > > > >
> > > > > > > > > > > Also, they tell developers to draw images to a specific size
> > > > > > > > > > > rather
> > > > > > > > > > > than using auto-sizing. That begs the question as to how they
> > > > > > > > > > > interpret a call to draw an image just using a location in the
> > > > > > > > > > > presence of various DPI factors.
> > > > > > > > > > There is an interesting doc that describes how to write
> > > > > > > > > > DPI-aware
> > > > > > > > > > Win32 applications:
> > > > > > > > > > http://msdn.microsoft.com/en-us/library/dd464646%28v=vs.85%29.aspx \
> > > > > > > > > >
> > > > > > > > > > It is suggested to handle WM_DPICHANGED message, load the
> > > > > > > > > > graphic
> > > > > > > > > > that has slightly greater resolution to the current DPI and use
> > > > > > > > > > StretchBlt
> > > > > > > > > > to scale down the image.
> > > > > > > > > >
> > > > > > > > > > Thanks,
> > > > > > > > > > Alexandr.
> > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > ...jim
> > > > > > > > > > >
> > > > > > > > > > > On 2/7/14 3:00 AM, Alexander Scherbatiy wrote:
> > > > > > > > > > > > On 1/22/2014 6:40 AM, Jim Graham wrote:
> > > > > > > > > > > > > Hi Alexander,
> > > > > > > > > > > > >
> > > > > > > > > > > > > Before we get too far down the road on this API, I think we
> > > > > > > > > > > > > understand
> > > > > > > > > > > > > the way in which MacOS processes multi-resolution images \
> > > > > > > > > > > > > for HiDPI
> > > > > > > > > > > > > screens, but have we investigated the processes that \
> > > > > > > > > > > > > Windows uses
> > > > > > > > > > > > > under Windows 8? My impression is that Windows 8 has
> > > > > > > > > > > > > included a
> > > > > > > > > > > > > number of new techniques for dealing with the high \
> > > > > > > > > > > > > resolution displays
> > > > > > > > > > > > > that it will run on in the Windows tablet and mobile
> > > > > > > > > > > > > industries
> > > > > > > > > > > > > and
> > > > > > > > > > > > > that these will also come into play as 4K displays (already
> > > > > > > > > > > > > available)
> > > > > > > > > > > > > become more common on the desktop. We should make sure \
> > > > > > > > > > > > > that what we
> > > > > > > > > > > > > come up with here can provide native compatibility with
> > > > > > > > > > > > > either
> > > > > > > > > > > > > platform's policies and standard practices.
> > > > > > > > > > > > >
> > > > > > > > > > > > > If you've investigated the MS policies I'd like to see a
> > > > > > > > > > > > > summary so
> > > > > > > > > > > > > that we can consider them as we review this API...
> > > > > > > > > > > > There is the Windows Guidelines for scaling to pixel
> > > > > > > > > > > > density:
> > > > > > > > > > > > \
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> > > > > > > > > > > > \
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > which says that Windows has automatic resource loading
> > > > > > > > > > > > that
> > > > > > > > > > > > supports
> > > > > > > > > > > > three version of images scaling (100%, 140%, and 180%)
> > > > > > > > > > > > --------------------------------
> > > > > > > > > > > > Without scaling, as the pixel density of a display device
> > > > > > > > > > > > increases, the
> > > > > > > > > > > > physical sizes of objects on screen get smaller.
> > > > > > > > > > > > When UI would otherwise be too small to touch and when text
> > > > > > > > > > > > gets
> > > > > > > > > > > > too
> > > > > > > > > > > > small to read,
> > > > > > > > > > > > Windows scales the system and app UI to one of the following
> > > > > > > > > > > > scaling
> > > > > > > > > > > > plateaus:
> > > > > > > > > > > >
> > > > > > > > > > > > 1.0 (100%, no scaling is applied)
> > > > > > > > > > > > 1.4 (140% scaling)
> > > > > > > > > > > > 1.8 (180% scaling)
> > > > > > > > > > > >
> > > > > > > > > > > > Windows determines which scaling plateau to use based on the
> > > > > > > > > > > > physical
> > > > > > > > > > > > screen size, the screen resolution, the DPI of the screen, \
> > > > > > > > > > > > and form
> > > > > > > > > > > > factor.
> > > > > > > > > > > >
> > > > > > > > > > > > Use resource loading for bitmap images in the app package For
> > > > > > > > > > > > bitmap
> > > > > > > > > > > > images stored
> > > > > > > > > > > > in the app package, provide a separate image for each scaling
> > > > > > > > > > > > factor(100%, 140%, and 180%),
> > > > > > > > > > > > and name your image files using the "scale" naming convention
> > > > > > > > > > > > described
> > > > > > > > > > > > below.
> > > > > > > > > > > > Windows loads the right image for the current scale
> > > > > > > > > > > > automatically.
> > > > > > > > > > > > --------------------------------
> > > > > > > > > > > >
> > > > > > > > > > > > The image name convention for the various scales is:
> > > > > > > > > > > > images/logo.scale-100.png
> > > > > > > > > > > > images/logo.scale-140.png
> > > > > > > > > > > > images/logo.scale-180.png
> > > > > > > > > > > >
> > > > > > > > > > > > The 'ms-appx:///images/logo.png' uri is used to load the
> > > > > > > > > > > > image
> > > > > > > > > > > > in an
> > > > > > > > > > > > application.
> > > > > > > > > > > >
> > > > > > > > > > > > If we want to support this in the same way as it is done
> > > > > > > > > > > > for Mac
> > > > > > > > > > > > OS X
> > > > > > > > > > > > the WToolkit should return MultiResolution image in case if
> > > > > > > > > > > > the
> > > > > > > > > > > > loaded image has .scale-* qualifiers.
> > > > > > > > > > > > The Graphics class can request an image with necessary
> > > > > > > > > > > > resolution
> > > > > > > > > > > > from the MultiResolution image.
> > > > > > > > > > > >
> > > > > > > > > > > > It seems that nothing should be changed in the
> > > > > > > > > > > > MultiResolution
> > > > > > > > > > > > interface in this case.
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks,
> > > > > > > > > > > > Alexandr.
> > > > > > > > > > > > >
> > > > > > > > > > > > > ...jim
> > > > > > > > > > > > >
> > > > > > > > > > > > > On 1/14/14 2:54 AM, Alexander Scherbatiy wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Hello,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Could you review the fix:
> > > > > > > > > > > > > > bug: https://bugs.openjdk.java.net/browse/JDK-8029339
> > > > > > > > > > > > > > webrev:
> > > > > > > > > > > > > > http://cr.openjdk.java.net/~alexsch/8029339/webrev.00
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > This is a proposal to introduce an API that allows to
> > > > > > > > > > > > > > create a
> > > > > > > > > > > > > > custom
> > > > > > > > > > > > > > multi resolution image.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > I. It seems reasonable that the API should provide two \
> > > > > > > > > > > > > > basic operations:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 1. Get the resolution variant based on the requested \
> > > > > > > > > > > > > > image width and
> > > > > > > > > > > > > > height:
> > > > > > > > > > > > > > - Image getResolutionVariant(int width, int height)
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Usually the system provides the scale factor which
> > > > > > > > > > > > > > represents
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > number of pixels corresponding to each linear unit on the
> > > > > > > > > > > > > > display.
> > > > > > > > > > > > > > However, it has sense to combine the scale factor and
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > current
> > > > > > > > > > > > > > transformations to get the actual image size to be
> > > > > > > > > > > > > > displayed.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 2. Get all provided resolution variants:
> > > > > > > > > > > > > > - List<Image> getResolutionVariants()
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > There are several uses cases:
> > > > > > > > > > > > > > - Create a new multi-resolution image based on the given
> > > > > > > > > > > > > > multi-resolution image.
> > > > > > > > > > > > > > - Pass to the native system the multi-resolution
> > > > > > > > > > > > > > image. For
> > > > > > > > > > > > > > example,
> > > > > > > > > > > > > > a use can set to the system the custom multi-resolution
> > > > > > > > > > > > > > cursor.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > II. There are some possible ways where the new API can be \
> > > > > > > > > > > > > > added
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 1. java.awt.Image.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > The 2 new methods can be added to the Image class. A user
> > > > > > > > > > > > > > can
> > > > > > > > > > > > > > override
> > > > > > > > > > > > > > the getResolutionVariant() and getResolutionVariants()
> > > > > > > > > > > > > > methods to
> > > > > > > > > > > > > > provide the resolution variants
> > > > > > > > > > > > > > or there can be default implementations of these methods
> > > > > > > > > > > > > > if a
> > > > > > > > > > > > > > user
> > > > > > > > > > > > > > puts resolution variants
> > > > > > > > > > > > > > to the list in the sorted order.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > To check that the image has resolution variants the
> > > > > > > > > > > > > > following
> > > > > > > > > > > > > > statement can be used: \
> > > > > > > > > > > > > > image.getResolutionVariants().size()
> > > > > > > > > > > > > > != 1
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > The disadvantage is that there is an overhead that the
> > > > > > > > > > > > > > Image
> > > > > > > > > > > > > > class
> > > > > > > > > > > > > > should contain the List object and not all
> > > > > > > > > > > > > > images can have resolution variants.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 2. Introduce new MultiResolutionImage interface.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > A user should extend Image class and implement the
> > > > > > > > > > > > > > MultiResolutionImage interface.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > For example:
> > > > > > > > > > > > > > ---------------------
> > > > > > > > > > > > > > public class CustomMultiResolutionImage extends
> > > > > > > > > > > > > > BufferedImage
> > > > > > > > > > > > > > implements MultiResolutionImage {
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Image highResolutionImage;
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > public CustomMultiResolutionImage(BufferedImage
> > > > > > > > > > > > > > baseImage,
> > > > > > > > > > > > > > BufferedImage highResolutionImage) {
> > > > > > > > > > > > > > super(baseImage.getWidth(),
> > > > > > > > > > > > > > baseImage.getHeight(),
> > > > > > > > > > > > > > baseImage.getType());
> > > > > > > > > > > > > > this.highResolutionImage = highResolutionImage;
> > > > > > > > > > > > > > Graphics g = getGraphics();
> > > > > > > > > > > > > > g.drawImage(baseImage, 0, 0, null);
> > > > > > > > > > > > > > g.dispose();
> > > > > > > > > > > > > > }
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > @Override
> > > > > > > > > > > > > > public Image getResolutionVariant(int width, int
> > > > > > > > > > > > > > height) {
> > > > > > > > > > > > > > return ((width <= getWidth() && height <=
> > > > > > > > > > > > > > getHeight()))
> > > > > > > > > > > > > > ? this : highResolutionImage;
> > > > > > > > > > > > > > }
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > @Override
> > > > > > > > > > > > > > public List<Image> getResolutionVariants() {
> > > > > > > > > > > > > > return Arrays.asList(this,
> > > > > > > > > > > > > > highResolutionImage);
> > > > > > > > > > > > > > }
> > > > > > > > > > > > > > }
> > > > > > > > > > > > > > ---------------------
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > The current fix adds the MultiResolutionImage interface
> > > > > > > > > > > > > > and
> > > > > > > > > > > > > > public
> > > > > > > > > > > > > > resolution variant rendering hints.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > Alexandr.
> > > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > >
> > > > > >
> > > > >
> > >
>
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