Drawing Images in Native Window in NDK

[vijayasarathy m]

Dear all,

I need a help in Drawing Images in ANativeWindow in NDK.

I am trying to draw a 320 * 240 image in ANativeWindow in NDK using below code.

ANativeWindow_setBuffersGeometry(player.nativeWindow, 320, 240, WINDOW_FORMAT_RGB_565) ;  // Called only once

The above code is called only once in the init function.

The Window is passed from application as a surface. The Surface is OpenGLSurface in Application

In a thread, below code is used to draw on Native Window

ANativeWindow_acquire(nativeWindow);

if(ANativeWindow_lock(nativeWindow,&outBuffer,NULL) < 0)

{

LOGE("Native Window Lock Failed....");

return -1;

}

memcpy(outBuffer.bits,frame->data,320*240*2);

if(ANativeWindow_unlockAndPost(is->nativeWindow) < 0)

{

    LOGE("Native Window unlock and post failed");

}

return;

But the image that is being drawn on the device is not full.It looks like a zoomed Image.It is drawing only a part of the image.

Whereas when I dump the frame that is being copied to Native Window Outbuffer, the image is perfect as 320*240 image

The App is Run in Landscape Mode. The Display size is 800 * 480. The Open GL Surface Dimension is 320 * 240.

Please let me know, whether I am missing something or Its a bug in ANativeWindow.

Thanks & Regards

Vijayasarathy.M

[Ken Turkowski]

There are a couple of things that could be happening:

(1) Just because you ask for a window with format RGB565 doesn't mean that you will get it. With GL, at least, you will get something that is compatible with it.

(2) The Y stride is probably not 640 bytes; with the display being 800 pixels wide, the stride could well be 1600 bytes.

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[vijayasarathy m]

Dear Turk,

I am printing the parameters of outbuffer after doing ANativeWindow_lock which gives me below log

outbuffer, width=320, height=240, stride=320,format=4 bits=0x5d7d9000

As Per this stride is 320 and format is 4 which is WINDOW_FORMAT_RGB_565 as per native_window.h.

Thanks & Regards,

Vijayasarathy.M