[OpenJDK 2D-Dev] Review request for 8029339 Custom MultiResolution image support on HiDPI displays
Sergey Bylokhov
Sergey.Bylokhov at oracle.com
Wed Apr 1 12:02:02 UTC 2015
Hello, Jim.
27.03.15 0:48, Jim Graham wrote:
> RenderingHints.java:
>
> Where do we process this hint? Don't we need to pass it to the
> getVariant() method?
>
> I don't understand the hint values other than the one that always uses
> the base image. Default I guess gives us the ability to use the Mac
> algorithm of "next larger size" on Mac and "based on Screen DPI" on
> Windows, but the 3rd value "ON" is so vague as to not have any
> meaning. Perhaps we should just delete it, but then do we just always
> do the Mac method? Or do we vaguely have our internal images have a
> platform-specific method and the Abstract/Base classes just do what
> they want with no control from the user? In FX we are also still
> struggling with this issue and we may likely just do what the Mac does
> in all cases, but perhaps AWT needs to "behave like the platform"
> more? If we are going to have actual values, then we need to have
> them do something, which means:
>
> - SG2D needs to track the hint just like we do the other hints that
> affect our processing
> - MRI.getVariant() needs to have the hint as an argument
> - BaseMRI should probably do something with that hint
> - hint values should include:
> - ..._DEFAULT - implementation gets to decide
> - ..._BASE - always use the base image
> - ..._SIZE_FIT - Mac algorithm of smallest image that is big enough
> - ..._DPI_FIT - choose based on DPI of the screen, ignoring transform
I did not watch this discussion, but I have a question about use of dpi
vs scale. Why we cannot make things simpler and provide only
width+height to the getResolutionVariant()?
Like this:
Image getResolutionVariant(float destImageWidth, float destImageWidth);
All other things can be calculated internally by this method.
We will pass width and height, based on the hints which were set to the
SG2D.
By default this hint will be _FULL_SIZE_FIT like on osx and width/height
will include full transformation(dev+usr),
On windows for Window and VolatileImages this will be _DPI_FIT and
width/height will include dev transformation only.
It is unclear what hint should be default in BufferedImage on windows.
List of the hints should looks like:
- ..._DEFAULT - implementation gets to decide
- ..._BASE - always use the base image
- ..._FULL_SIZE_FIT - Mac algorithm of smallest image that is big
enough
- ..._DEFAULT_DPI_FIT - choose based on DPI of the screen, ignoring
transform
- ..._USR_DPI_FIT - choose based on users transform, ignoring
device transform.
Names can be tweaked for sure.
It seems we will cover all possible cases in such solution, no?
> line 978 - missing blank line between fields
>
> SG2D.java:
>
> - The interface says that you will be passing in the "logical DPI" of
> the display, but here you are actually passing in the screen's scale
> factor.
>
>
> On 3/13/15 6:34 AM, Alexander Scherbatiy wrote:
>>
>> Hello,
>>
>> Could you review the proposed API based on MultiresolutionImage
>> interface:
>> http://cr.openjdk.java.net/~alexsch/8029339/webrev.06/
>>
>> - return unmodifiable list comment is added to the
>> getResolutionVariants() method javadoc in MultiresolutionImage interface
>> - base image size arguments are removed form the
>> getResolutionVariant(...) method in MultiresolutionImage interface
>> - BaseMultiResolutionImage class that allows to create a
>> multi-resolution image based on resolution variant array is added
>> - the test for the BaseMultiResolutionImage is added
>>
>> Thanks,
>> Alexandr.
>>
>> On 2/14/2015 3:23 AM, Jim Graham wrote:
>>> The second solution looks good. I'd make it standard practice
>>> (perhaps even mentioned in the documentation) to return unmodifiable
>>> lists from the getVariants() method. The Collections class provides
>>> easy methods to create these lists, and it sends a clear message to
>>> the caller that the list was provided for them to read, but not write
>>> to. Otherwise they may add a new image to the list you provided them
>>> and wonder why it wasn't showing up. Also, an unmodifiable list can
>>> be cached and reused for subsequent calls without having to create a
>>> new list every time.
>>>
>>> In getResolutionVariant() was there a reason why the base dimensions
>>> were provided as float? The destination dimensions make sense as
>>> float since they could be the result of a scale, but the source
>>> dimensions are typically getWidth/getHeight() on the base image. A
>>> related question would be if they are needed at all, since the
>>> implementation should probably already be aware of what the base image
>>> is and what its dimensions are. I'm guessing they are provided
>>> because the implementation in SG2D already knows them and it makes it
>>> easier to forward the implementation on to a shared (static?) method?
>>>
>>> With respect to default implementations, I take it that the BaseMRI is
>>> along the pattern that we see in Swing for Base classes. Would it be
>>> helpful to provide an implementation (in addition or instead) that
>>> allows a developer to take a bunch of images and quickly make an MRI
>>> without having to override anything? The implementations of
>>> getBaseImage() and getResolutionVariants() are pretty straightforward
>>> and a fairly reasonable default algorithm can be provided for
>>> getRV(dimensions). This question is more of an idle question for my
>>> own curiosity than a stumbling block...
>>>
>>> ...jim
>>>
>>> On 1/22/2015 6:49 AM, Alexander Scherbatiy wrote:
>>>>
>>>> Hi Phil,
>>>>
>>>> I have prepared two versions of the proposed API:
>>>>
>>>> I) Resolution variants are added directly to the Image:
>>>> http://cr.openjdk.java.net/~alexsch/8029339/list/webrev.00
>>>>
>>>> II) MultiResolutionImage interface is used:
>>>> http://cr.openjdk.java.net/~alexsch/8029339/webrev.05
>>>>
>>>> It could help to decide which way should be chosen for the the
>>>> multi-resolution image support.
>>>>
>>>> Below are some comments:
>>>>
>>>> 1. High level goal:
>>>> Introduce an API that allows to create and handle an image with
>>>> resolution variants.
>>>>
>>>> 2. What is not subject of the provided API
>>>> - Scale naming convention for high-resolution images
>>>> - Providing pixel scale factor for the screen/window
>>>>
>>>> 3. Use cases
>>>> 3.1 Loading and drawing high-resolution icons in IntelliJ IDEA
>>>> A high-resolution image is loaded from resources and stored in
>>>> JBHiDPIScaledImage class which is a subclass of the buffered image.
>>>> The high-resolution image is used to create a disabled icon
>>>> in the
>>>> IconLoader.getDisabledIcon(icon) method.
>>>> https://github.com/JetBrains/intellij-community/blob/master/platform/util/src/com/intellij/openapi/util/IconLoader.java
>>>>
>>>>
>>>>
>>>>
>>>> 3.2 Loading and drawing high-resolution icons in NetBeans
>>>> NetBeans does not have support for the high-resolution icons
>>>> loading.
>>>> It loads an icon from the file system using
>>>> Toolkit.getDefaultToolkit().getImage(url) method or from resources
>>>> by ImageReader and store it in ToolTipImage class which is
>>>> subclass of the buffered image.
>>>> ImageUtilities.createDisabledIcon(icon) method creates a
>>>> disabled
>>>> icon by applying RGBImageFilter to the icon.
>>>> http://hg.netbeans.org/main/file/97dcf49eb4a7/openide.util/src/org/openide/util/ImageUtilities.java
>>>>
>>>>
>>>>
>>>>
>>>> 3.3 Loading system icons in JDK 1.8
>>>> JDK requests icons from the native system for system L&Fs and
>>>> applies filters for them.
>>>> See for example AquaUtils.generateLightenedImage() method:
>>>> http://hg.openjdk.java.net/jdk9/client/jdk/file/e6f48c4fad38/src/java.desktop/macosx/classes/com/apple/laf/AquaUtils.java
>>>>
>>>>
>>>>
>>>>
>>>> 4. HiDPI support for Images on different OSes
>>>>
>>>> 4.1 Mac OS X
>>>> Cocoa API contains NSImage that allows to work with image
>>>> representations: add/remove/get all representations.
>>>> It picks up an image with necessary resolution based on the
>>>> screen backing store pixel scale factor and applied transforms.
>>>> https://developer.apple.com/library/mac/documentation/Cocoa/Reference/ApplicationKit/Classes/NSImage_Class/Reference/Reference.html
>>>>
>>>>
>>>>
>>>>
>>>> 4.2 Linux
>>>> GTK+ 3 API has gtkcssimagescaled lib (it seems that it is not
>>>> public/stable)
>>>> that parses the -gtk-scaled css property and draws a
>>>> GtkCssImage
>>>> according to the given scale factor.
>>>>
>>>> I have not found information about the HiDPI support in Xlib.
>>>>
>>>> 4.3 Windows
>>>> I have only found the tutorial that suggests to select and
>>>> draw a
>>>> bitmap using the queried DPI
>>>> and scale the coordinates for drawing a rectangular frame
>>>> http://msdn.microsoft.com/en-us/library/dd464659%28v=vs.85%29.aspx
>>>>
>>>> Windows also provides the horizontal and vertical DPI of the
>>>> desktop
>>>> http://msdn.microsoft.com/en-us/library/windows/apps/dd371316
>>>>
>>>> 5. Pseudo API
>>>> Below are some ways which illustrates how multi-resolution
>>>> images
>>>> can be created and used.
>>>>
>>>> 5.1 Resolution variants are stored directly in Image class.
>>>> To query a resolution variant it needs to compare the resolution
>>>> variant width/height
>>>> with the requested high-resolution size.
>>>> ------------
>>>> public abstract class Image {
>>>>
>>>> public void addResolutionVariant(Image image) {...}
>>>> public List<Image> getResolutionVariants() {...}
>>>> }
>>>> ------------
>>>> // create a disabled image with resolution variants
>>>>
>>>> Image disabledImage = getDisabledImage(image);
>>>>
>>>> for (Image rv : image.getResolutionVariants()) {
>>>> disabledImage.addResolutionVariant(getDisabledImage(rv));
>>>> }
>>>> ------------
>>>> This approach requires that all resolution variants have been
>>>> created even not of them are really used.
>>>>
>>>> 5.2 Resolution variants are stored in a separate object that
>>>> allows to create them by demand.
>>>> To query a resolution variant it needs to compare the resolution
>>>> variant scale factor
>>>> with the requested scale (that can include both screen DPI scale
>>>> and applied transforms).
>>>> ------------
>>>> public abstract class Image {
>>>>
>>>> public static interface ResolutionVariant {
>>>> Image getImage();
>>>> float getScaleFactor();
>>>> }
>>>>
>>>> public void addResolutionVariant(ResolutionVariant
>>>> resolutionVariant) {...}
>>>> public List<ResolutionVariant> getResolutionVariants() {...}
>>>> }
>>>> ------------
>>>> // create a disabled image with resolution variants
>>>> Image disabledImage = getDisabledImage(image);
>>>>
>>>> for (Image.ResolutionVariant rv :
>>>> image.getResolutionVariants()) {
>>>> disabledImage.addResolutionVariant(new
>>>> Image.ResolutionVariant() {
>>>>
>>>> public Image getImage() {
>>>> return getDisabledImage(rv.getImage());
>>>> }
>>>>
>>>> public float getScaleFactor() {
>>>> return rv.getScaleFactor();
>>>> }
>>>> });
>>>> }
>>>> ------------
>>>>
>>>> It does not have problem if a predefined set of images is
>>>> provided
>>>> (like image.png and image at 2x.png on the file system).
>>>> This does not cover cases where a resolution variant can be
>>>> created
>>>> using the exact requested size (like loading icons from the native
>>>> system).
>>>> A resolution variant can be queried based on a scale factor and
>>>> applied transforms.
>>>>
>>>> 5.3 The provided example allows to create a resolution variant
>>>> using the requested high-resolution image size.
>>>> ------------
>>>> public interface MultiResolutionImage {
>>>> Image getResolutionVariant(float width, float height);
>>>> }
>>>> ------------
>>>> // create a multi-resolution image
>>>> Image mrImage = new AbstractMultiResolutionImage() {
>>>>
>>>> public Image getResolutionVariant(float width, float
>>>> height) {
>>>> // create and return a resolution variant with exact
>>>> requested width/height size
>>>> }
>>>>
>>>> protected Image getBaseImage() {
>>>> return baseImage;
>>>> }
>>>> };
>>>> ------------
>>>> // create a disabled image with resolution variants
>>>> Image disabledImage = null;
>>>> if (image instanceof MultiResolutionImage) {
>>>> final MultiResolutionImage mrImage = (MultiResolutionImage)
>>>> image;
>>>> disabledImage = new AbstractMultiResolutionImage(){
>>>>
>>>> public Image getResolutionVariant(float width, float
>>>> height) {
>>>> return
>>>> getDisabledImage(mrImage.getResolutionVariant(width, height));
>>>> }
>>>>
>>>> protected Image getBaseImage() {
>>>> return getDisabledImage(mrImage);
>>>> }
>>>> };
>>>> } else {
>>>> disabledImage = getDisabledImage(image);
>>>> }
>>>> ------------
>>>>
>>>> Thanks,
>>>> Alexandr.
>>
--
Best regards, Sergey.
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