How to match "MagImageScalingCallback" using JNA?

Question

I am using jna.jar, jna-3.2.5.jar and jna-3.3.0-platform.jar in my Java project.

This is the Winapi function that I want to replicate.

BOOL WINAPI MagImageScalingCallback( _In_ HWND hwnd, _In_ void *srcdata, _In_ MAGIMAGEHEADER srcheader, _Out_ void *destdata, _In_ MAGIMAGEHEADER destheader, _In_ RECT unclipped, _In_ RECT clipped, _In_ HRGN dirty ); 

This is my java code

 public interface MagImageScalingCallback extends StdCallLibrary.StdCallCallback{ public boolean MagImageScalingCallback(HWND hwnd, Pointer srcdata, MAGIMAGEHEADER.ByValue srcheader, Pointer destdata, MAGIMAGEHEADER.ByValue destheader, RectByValue source, RectByValue clipped, HRGN dirty); } 

When I enter this callback method, I get unexpected results:

  public boolean MagImageScalingCallback(HWND hwnd, Pointer srcdata, MAGIMAGEHEADER.ByValue srcheader, Pointer destdata, MAGIMAGEHEADER.ByValue destheader, RectByValue source, RectByValue clipped, HRGN dirty) { image.setRGB(0, 0, srcheader.width, srcheader.height, srcdata.getIntArray(0, srcheader.width * srcheader.height ), 0, srcheader.width); return true; } 

This table explains what works and what doesn't work on 32-bit and 64-bit systems when I change the data type of variables.

 +--------------+--------------+-------------+-------------+ | Parameter | Data type | 64 bit | 32 bit | +--------------+--------------+-------------+-------------+ | source | WinDef.RECT | Working | Not Working | | clipped | WinDef.RECT | Working | Not Working | | source | RectByValue | Working | Working | | source | RectByValue | Working | Working | | srcdata | Pointer | Working | Not Working | | destdata | Pointer | Working | Not Working | +--------------+--------------+-------------+-------------+ 

Not working means a completely black image as a result

If I use the above code on a 64-bit system, I can capture the desktop (I can access the data from a pointer variable). If I use the same code on a 32-bit system, I do not get any image. You can see all my code

Why is there an error in my code? How can i fix this?

For your information. As you see in screenSkip.java , whenever the MagSetWindowSource function is called. Called by MagImageScalingCallback (on line 80).

Problems in this section of code

If I run this code on a 64-bit system, srcdata and destdata will hold an array of integer pixels on the desktop (if I save this as an image, it captures the desktop). But if I run the same code on a 32-bit system, then both values ​​of a variable pixel of a variable are always zero (if I save an image, it is always black)

64-bit system [! [enter image description here] [2]] [2]

32 bit system

@ david-heffernan I am running this code on a 32 bit system. I know The Magnification API is not supported under WOW64; . This means that a 32-bit zoom application runs on a 32-bit system, and a 64-bit zoom application runs on a 64-bit system. Please stop commenting that the zoom API is not working on WOW64 and is trying to execute this code on a 32-bit system.

As for your request, the figure below shows the configuration of my system.

Answer 1

The callback is correct - there are no flaws in the code, in addition, you use outdated functions.

Think about it:

  try { Rectangle screenRect = new Rectangle(Toolkit.getDefaultToolkit().getScreenSize()); BufferedImage capture = new Robot().createScreenCapture(screenRect); ImageIO.write(capture, "JPEG", new File("printed1.jpg")); } catch (Exception e) { e.printStackTrace(); }