Your example here is  not what I wrote :-

443 * Image nativeResImage;
444 * Image baseResImage;
445 * MultiResolutionImage mrImage = robot.createMultiResolutionScreenCapture(frame.getBounds());
446 * List<Image> resolutionVariants = mrImage.getResolutionVariants();
447 * if (resolutionVariants.size() > 1) {
448 * nativeResImage = resolutionVariants.get(1);
449 * } else {
450 * baseResImage = resolutionVariants.get(0);
451 * } </pre>


The result of that example is that only one of

nativeResImage or baseResImage  is non-null and the developer then needs
to check again.
I defined only nativeResImage on purpose. If there is only one resolution
variant then it must be the nativeResImage .. so the way I coded it was
trying to show how you always get the unscaled result.

So I recommend updating it as I originally suggested.

Also please file the CCC today - the example part won't hold up that
since it is not spec. significant.

-phil.


On 02/09/2017 01:49 AM, Prem Balakrishnan wrote:

Hi Phil,

Thank you for the review.

Updated patch: http://cr.openjdk.java.net/~pkbalakr/8162959/webrev.10/ <http://cr.openjdk.java.net/%7Epkbalakr/8162959/webrev.10/>

Regards,

Prem

*From:*Phil Race
*Sent:* Thursday, February 09, 2017 1:59 AM
*To:* Prem Balakrishnan; Alexander Scherbatiy
*Cc:* Sergey Bylokhov; awt-dev@openjdk.java.net
*Subject:* Re: Review Request JDK:-8162959 [HiDPI] screenshot artifacts using AWT Robot

Two minor grammar issues in the javadoc

This method should be used in case where there is a scaling transform
->
This method can be used in case there is a scaling transform
* For a high resolution display where there is scaling transform,
->
* For a high resolution display where there is a scaling transform,


Also I think we should show as an example in the javadoc how you would use it to get the hi-res image if you want it.
Derived fom Alexander's off-list email :
        Image nativeResImage;
MultiResolutionImage mrImage = robot.createMultiResolutionScreenCapture(frame.getBounds());
        List<Image> resolutionVariants = mrImage.getResolutionVariants();
        if (resolutionVariants.size() > 1) {
            nativeResImage = resolutionVariants.get(1);
        } else {
            nativeResImage = resolutionVariants.get(0);
        }

-phil.

On 02/08/2017 12:48 AM, Prem Balakrishnan wrote:

    Thank you Alex for the review.

    Updated patch:
    http://cr.openjdk.java.net/~pkbalakr/8162959/webrev.09/
    <http://cr.openjdk.java.net/%7Epkbalakr/8162959/webrev.09/>

    Regards,

    Prem

    *From:*Alexandr Scherbatiy
    *Sent:* Tuesday, February 07, 2017 10:54 PM
    *To:* Prem Balakrishnan; Philip Race
    *Cc:* Sergey Bylokhov; awt-dev@openjdk.java.net
    <mailto:awt-dev@openjdk.java.net>
    *Subject:* Re: Review Request JDK:-8162959 [HiDPI] screenshot
    artifacts using AWT Robot

    On 2/6/2017 1:19 PM, Prem Balakrishnan wrote:


    Hi Phil  and  Alex,

    Please review updated patch as per review comments.

    http://cr.openjdk.java.net/~pkbalakr/8162959/webrev.08/
    <http://cr.openjdk.java.net/%7Epkbalakr/8162959/webrev.08/>


      Just as a small optimization. The private method
    Robot.createCompatibleImage(...) can return an array of
    BufferedImage-s.
      The createScreenCapture(...) can return just an image from the
    zero index and the createMultiResolutionScreenCapture(...) returns
    BaseMultiResolutionImage(array of images).

      It is better if the public javadoc part is checked by a native
    speaker.

      Thanks,
      Alexandr.


    Multi-monitor scenario will be handled under JDK-8173972.

    https://bugs.openjdk.java.net/browse/JDK-8173972

    Regards,

    Prem

    *From:*Phil Race
    *Sent:* Tuesday, January 31, 2017 5:24 AM
    *To:* Prem Balakrishnan; Alexander Scherbatiy
    *Cc:* Sergey Bylokhov; awt-dev@openjdk.java.net
    <mailto:awt-dev@openjdk.java.net>
    *Subject:* Re: Review Request JDK:-8162959 [HiDPI] screenshot
    artifacts using AWT Robot

    I like

    3. createMultiresolutionScreenCapture(Rectangle rect);




    -phil.



    On 01/30/2017 01:11 AM, Prem Balakrishnan wrote:

        Hi Phil,

        Thank you for the review.

        >Is Robot only capable of a screen capture from the default
        screen ? I hope not.

        Robot.createScreenCapture() can be used to capture screenshots
        on Multi-Monitor as well.

        To capture screen on Multi-Monitor user should calculate the
        total width of multiple

         screens, based on the position of secondary monitor(i.e.,
        Right/Left) with respect to

        main monitor and pass it  to createScreenCapture() method.

        >So I would expect that where there are two screens with
        different DPI settings/transforms
        >the logic in here will be sensitive to the target screen.

        I tried with MacBookPro (macOS Sierra version 10.12 , Retina )
        by connecting a secondary monitor non-Retina display.

        keeping secondary monitor to the right/left of main display
        and targeted rectangle on each sides, expected results are
        obtained.

        The current patch addresses most common scenario of single
        HiDPI monitor setup and dual monitor (Hi-DPI, non-HiDPI) setup.

        As “Handling multi monitor setup with different DPI settings”
        requires additional effort to make it work on all platforms, I
        propose to fix it separately.

        >And what happens if the target rectangle overlaps the edge
        between two screens ?

        I tried this scenario with Mac connecting non-retina secondary
        monitor,  OS doesn’t allow user to place a window in between
        two screens.

        >The more significant API change is that the isHiDPI parameter
        is a misnomer.
        >It really means something else and I think what we should do
        is delete it
        >and change the method name to something else.

        Thank you for the Draft.

        From my point of view, I think we should maintain the method
        name “createScreenCapture()”, because two functions doing the
        same task

        should have the same name so that  method will have maximum
        proximal visibility i.e., developer will easily know that
        there exists two method variants to take screenshots.

        (At least the method name should start with create….);

        Some of the signatures  we can choose from:
        1. createScreenCapture(int x, int y, int width, int height);

        2. createScreenCapture(Point pt, Dimension d);

        3. createMultiresolutionScreenCapture(Rectangle rect);

        4. createMultiImageScreenCapture(Rectangle rect);

        Request your feedback on the same.

        Once we finalize the signature and behavior, I  shall update
        the patch and send it for review.

        Regards,

        Prem

        *From:*Philip Race
        *Sent:* Wednesday, January 25, 2017 11:44 PM
        *To:* Alexandr Scherbatiy
        *Cc:* Prem Balakrishnan; Sergey Bylokhov;
        awt-dev@openjdk.java.net <mailto:awt-dev@openjdk.java.net>
        *Subject:* Re: Review Request JDK:-8162959 [HiDPI] screenshot
        artifacts using AWT Robot

        I'd like to propose some revision to the API and also have a
        question about the implementation.

        The question about the implementation concerns this code :-

        465         AffineTransform tx = GraphicsEnvironment.

466 getLocalGraphicsEnvironment().getDefaultScreenDevice().

467 getDefaultConfiguration().getDefaultTransform();

        468         double uiScaleX = tx.getScaleX();

        469         double uiScaleY = tx.getScaleY();


        Is Robot only capable of a screen capture from the default
        screen ? I hope not.
        So I would expect that where there are two screens with
        different DPI settings/transforms
        the logic in here will be sensitive to the target screen.
        And what happens if the target rectangle overlaps the edge
        between two screens ?

        Regarding the API, I think that it needs to explain that it is
        "not 'hi dpi" per se,
        rather that it is the non-default transform that matters.

        Additionally the doc should properly link to the class names,
        not just write them
        as words.

        The more significant API change is that the isHiDPI parameter
        is a misnomer.
        It really means something else and I think what we should do
        is delete it
        and change the method name to something else.

        Here is my draft :
         /**
          * Creates an image containing pixels read from the screen.
          * This image does not include the mouse cursor.
          * This method should be used in case there is a scaling
        transform from
          * user space to screen (device) space.
          * Typically this means that the display is a high resolution
        screen,
          * although strictly it means any case in which there is such
        a transform.
          * Returns a {@link java.awt.image.BufferedImage} for a
        non-scaled display and
          * a {@link java.awt.image.MultiResolutionImage} where there
        is a scaling
          * transform.
          * <p>
          * The {@code MultiResolutionImage} will have two image variants:
          * <ul>
          * <li> Base Image with user specified size. This is scaled
        from the screen.
          * <li> Native device resolution image with device size pixels.
          * </ul>
          * @param   screenRect     Rect to capture in screen coordinates
          * @return  The captured image
          * @throws  IllegalArgumentException if {@code screenRect}
        width and height
          * are not greater than zero
          * @throws  SecurityException if {@code readDisplayPixels}
        permission
          * is not granted
          * @see     SecurityManager#checkPermission
          * @see     AWTPermission
          */

         public synchronized Image multiImageeScreenCapture(Rectangle
        screenRect);

        -phil.

        On 1/20/17, 3:20 AM, Alexandr Scherbatiy wrote:

        On 1/19/2017 3:57 PM, Prem Balakrishnan wrote:

            Hi Alex,

            Please review updated patch as per review comments.

            http://cr.openjdk.java.net/~pkbalakr/8162959/webrev.06/
            <http://cr.openjdk.java.net/%7Epkbalakr/8162959/webrev.06/>

            Automated test validates both Robot.getPixelColor() and
            output of Robot.createScreenCapture() API's.

            Jtreg and JCK tests passed on build with fix across all
            the platforms(Mac, Windows and Linux) without causing any
            regression.

        src/java.desktop/share/classes/java/awt/Robot.java
          > 421      * @param   isHiDPI     Indicates if HiDPI Display

          There should be mention that this argument value is ignored
        when a screenshot is taken on non-HiDPI display

          Thanks,
          Alexandr.





        Regards,

        Prem

        *From:*Alexandr Scherbatiy
        *Sent:* Thursday, January 12, 2017 2:39 PM
        *To:* Prem Balakrishnan; Sergey Bylokhov;
        awt-dev@openjdk.java.net <mailto:awt-dev@openjdk.java.net>;
        Philip Race
        *Subject:* Re: Review Request JDK:-8162959 [HiDPI] screenshot
        artifacts using AWT Robot


        > 421      * @param   isHiDPI     Indicates if HiDPI Display

          There should be mention that this argument value is ignored
        when a screenshot is taken on non-HiDPI display

        Please also check the the method Robot.getPixelColor(int x,
        int y) also correctly works on Mac OS X, Windows and Linux
        after the fix.

        Thanks,
        Alexandr.

        On 1/10/2017 11:54 AM, Prem Balakrishnan wrote:

            Hi Alex,

            Please review updated patch,

            http://cr.openjdk.java.net/~pkbalakr/8162959/webrev.05/
            <http://cr.openjdk.java.net/%7Epkbalakr/8162959/webrev.05/>

            updated imageOption to kCGWindowImageBestResolution  which
            returns Best Resolution Image while capturing screen using
            CGWindowListCreateImage() method.

            Regards,

            Prem

            *From:*Alexandr Scherbatiy
            *Sent:* Tuesday, January 10, 2017 1:08 AM
            *To:* Prem Balakrishnan; Sergey Bylokhov;
            awt-dev@openjdk.java.net
            <mailto:awt-dev@openjdk.java.net>; Philip Race
            *Subject:* Re: Review Request JDK:-8162959 [HiDPI]
            screenshot artifacts using AWT Robot


              CGWindowListCreateImage() method which is used to
            capture a screenshot on Mac OS X by Robot has imageOption
            argument which can have value: kCGWindowImageBestResolution
            
https://developer.apple.com/reference/coregraphics/1666230-quartz_window_services/window_image_types?language=objc
               "When capturing the window, return the best image
            resolution. The returned image size may be different than
            the screen size."

              Could this option help to get a high-resolution
            CGImageRef on HiDPI display?

              Thanks,
              Alexandr.

            On 12/27/2016 12:14 PM, Prem Balakrishnan wrote:

                Hi Alexander,

                Please review updated patch,

                http://cr.openjdk.java.net/~pkbalakr/8162959/webrev.04/
                <http://cr.openjdk.java.net/%7Epkbalakr/8162959/webrev.04/>


                I used  wrong bounds while creating images, correct it
                in this patch.

                Regards,

                Prem

                *From:*Alexander Scherbatiy
                *Sent:* Wednesday, December 14, 2016 5:18 PM
                *To:* Prem Balakrishnan; Sergey Bylokhov;
                awt-dev@openjdk.java.net
                <mailto:awt-dev@openjdk.java.net>; Philip Race
                *Subject:* Re: Review Request JDK:-8162959 [HiDPI]
                screenshot artifacts using AWT Robot

                On 07/12/16 10:24, Prem Balakrishnan wrote:







                Hi Alexander,

                Please review updated patch as per review comments.

                http://cr.openjdk.java.net/~pkbalakr/8162959/webrev.03/
                <http://cr.openjdk.java.net/%7Epkbalakr/8162959/webrev.03/>

                  I used a simple app [1] to create a screenshot of a
                frame on Mac OS X:
                        Rectangle rect = frame.getBounds();
                rect.setLocation(frame.getLocationOnScreen());
                        BufferedImage img =
                robot.createScreenCapture(rect);

                  It takes only bottom right quarter of the frame [2].

                  Is it possible to use some API that makes a
                screenshot and returns an NSImage on Mac OS X?
                  In this case it would be possible to get a high
                resolution representation from the NSImage and return
                it in the same way as it is updated on Windows and Linux.

                  [1]
                
http://cr.openjdk.java.net/~alexsch/8162959/screenshot/RobotScreenshot.java
                
<http://cr.openjdk.java.net/%7Ealexsch/8162959/screenshot/RobotScreenshot.java>
                  [2]
                
http://cr.openjdk.java.net/~alexsch/8162959/screenshot/screenshot.png
                
<http://cr.openjdk.java.net/%7Ealexsch/8162959/screenshot/screenshot.png>

                  Thanks,
                  Alexandr.







                Regards,

                Prem

                *From:*Alexandr Scherbatiy
                *Sent:* Monday, November 21, 2016 8:10 PM
                *To:* Prem Balakrishnan; Sergey Bylokhov;
                awt-dev@openjdk.java.net
                <mailto:awt-dev@openjdk.java.net>; Phil Race
                *Subject:* Re: Review Request JDK:-8162959 [HiDPI]
                screenshot artifacts using AWT Robot

                On 11/16/2016 8:46 AM, Prem Balakrishnan wrote:








                Hi Alexander,

                Please review update patch as per review comments.

                http://cr.openjdk.java.net/~pkbalakr/8162959/webrev.02/
                <http://cr.openjdk.java.net/%7Epkbalakr/8162959/webrev.02/>

                With this patch, Robot.createScreenCapture(Rectangle)
                method returns a scaled down image on the HiDPI display.


                - The native part on Mac OS X and Linux should be
                updated as well.

                - 416      * Returns BufferedImage for Non-HiDPI
                display and MultiResolutionImage
                  417      * for HiDPI display with two resolution
                variants.

                There should be added an explanation what is the
                content of the first and the second resolution variant.

                Thanks,
                Alexandr.









                Regards,

                Prem

                *From:*Alexandr Scherbatiy
                *Sent:* Thursday, November 03, 2016 4:05 PM
                *To:* Prem Balakrishnan; Sergey Bylokhov;
                awt-dev@openjdk.java.net <mailto:awt-dev@openjdk.java.net>
                *Subject:* Re: Review Request JDK:-8162959 [HiDPI]
                screenshot artifacts using AWT Robot

                On 11/2/2016 1:57 PM, Prem Balakrishnan wrote:









                Hi Alexander,

                Please review updated patch.

                http://cr.openjdk.java.net/~pkbalakr/8162959/webrev.01/
                <http://cr.openjdk.java.net/%7Epkbalakr/8162959/webrev.01/>

                Added a new public API “*Image
                createHiDPIScreenCapture(Rectangle screenRect)”.*

                Returns an ordinary screenshot(BufferedImage) if the
                UI scale is 1.

                Returns MultiResolutionImage for HiDPI display with
                two resolution variants,

                1.Low Resolution/base image with user input width and
                height,  I have used interpolation algorithm for
                scaling , adapted from JavaFX Robot
                (http://hg.openjdk.java.net/openjfx/9-dev/rt/rev/89a5de54b7dc),

                2.High Resolution image with scaled width and height .

                  - Please, check that the
                Robot.createScreenCapture(Rectangle) method returns a
                scaled down image on the HiDPI display
                  - Probably existing Java methods can be used for an
                image scaling.
                  For example, there is the
                Image.getScaledInstance(int width, int height, int
                hints) method.
                  Or may be it is better just to create an image with
                required size and draw the high-resolution image into
                it using a specific scale and rendering hints.

                  Thanks,
                  Alexandr.










                Regards,

                Prem

                *From:*Alexander Scherbatiy
                *Sent:* Thursday, October 13, 2016 3:21 PM
                *To:* Prem Balakrishnan; Sergey Bylokhov;
                awt-dev@openjdk.java.net <mailto:awt-dev@openjdk.java.net>
                *Subject:* Re: Review Request JDK:-8162959 [HiDPI]
                screenshot artifacts using AWT Robot

                On 06/10/16 15:28, Prem Balakrishnan wrote:

                    Hi*,*

                    **

                    Please review fix for JDK 9,

                    *Bug:*https://bugs.openjdk.java.net/browse/JDK-8162959


                    
*Webrev:*http://cr.openjdk.java.net/~pkbalakr/8162959/webrev.00/
                    <http://cr.openjdk.java.net/%7Epkbalakr/8162959/webrev.00/>


                    I have adapted the same fix as used for JavaFX Robot

                    *Bug: *JDK-8162783
                    <https://bugs.openjdk.java.net/browse/JDK-8162783>.

                    *Patch:
                    
*http://hg.openjdk.java.net/openjfx/9-dev/rt/rev/89a5de54b7dc

                    New Public API ” BufferedImage
                    createScreenCapture(Rectangle screenRect, boolean
                    isHiDPI)”is added,

                    Which will have a parameter to specify if HiDPI.

                  It is better to a add public method which returns
                MultiResolution image on HiDPI display and  consists
                of two resoltion variants
                   - base image which has size requested by a user
                   - high-resolution image which creates an original
                screen capture

                  The proposed by your algorithm can be applied to the
                base image.
                  For more details see JDK-8020618 [macosx]
                java.awt.Robot makes blurry screen captures on Retina

                  Thanks,
                  Alexandr.










                Regards,

                Prem


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