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4 messages in net.java.dev.jna.usersRe: [jna-users] Arrays offset| From | Sent On | Attachments |
|---|---|---|
| Cyril Delmas | Mar 4, 2009 8:26 am | |
| Timothy Wall | Mar 4, 2009 8:40 am | |
| Cyril Delmas | Mar 4, 2009 8:50 am | |
| Timothy Wall | Mar 4, 2009 9:35 am |
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| Subject: | Re: [jna-users] Arrays offset | Actions... |
|---|---|---|
| From: | Timothy Wall (twal...@dev.java.net) | |
| Date: | Mar 4, 2009 9:35:52 am | |
| List: | net.java.dev.jna.users | |
On Mar 4, 2009, at 11:50 AM, Cyril Delmas wrote:
Ok for the array of pointers. The matter now is to translate this part : ==== LPBYTE lpImage = (LPBYTE) malloc ( sizeof(BYTE) * 3 * width * height );
Memory lpImage = new Memory(3 * width * height)
//// IT.data[0] = lpImage+2; // red channel IT.data[1] = lpImage+1; // green channel IT.data[2] = lpImage; // blue channel ==== I guess LPBYTE may be transformed in byte[], but how can I translate the last three lines ? I don't think it is possible in Java, as we can't access addresses...
data[0] = lpImage.share(2); data[1] = lpImage.share(1); data[2] = lpImage;
However, the offsets should probably be multiples of size (width* height), not single bytes, unless your RGB values are interleaved.
Timothy Wall a écrit :
It's an array of pointers, so use Pointer[] data = new Pointer[3]; what you assign to each pointer depends on your application. On Mar 4, 2009, at 11:27 AM, Cyril Delmas wrote:
Hi list, I want to transform this C code :
========== LPBYTE lpImage = (LPBYTE) malloc ( sizeof(BYTE) * 3 * width * height ); // initialize lpImage correctly
ImageTransfer IT; IT.columnBytes = 3; IT.rowBytes = 3 * width; IT.height = height; IT.width = width; IT.data[0] = lpImage+2; // red channel IT.data[1] = lpImage+1; // green channel IT.data[2] = lpImage; // blue channel
// use IT ==========
into the equivalent in Java using JNA.
I don't know which type I must use for "data" in the ImageTransfer structure :
typedef struct { int width; int height; int rowBytes; int columnBytes; unsigned char *data[3]; } ImageTransfer;
and don't know how to initialize the structure in Java (using Pointer, PointerByReference, ByteByReference or ByteBuffer ?). I tried some combinations, without success (access violation).