<AWT Dev> Review Request JDK:-8162959 [HiDPI] screenshot artifacts using AWT Robot

Alexandr Scherbatiy alexandr.scherbatiy at oracle.com
Thu Jan 12 09:09:23 UTC 2017


 > 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 at 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 at openjdk.java.net
>     <mailto:awt-dev at 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 at openjdk.java.net
>     <mailto:awt-dev at 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 at openjdk.java.net
>     <mailto:awt-dev at 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 at openjdk.java.net
>     <mailto:awt-dev at 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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