problem occuring when the image is added on the canvas

[ritusingh]

Hi Frens,


I have implemented canvas class in j2me in that i have added image of specified size
on screen.when i am running that application on device first of all white screen is
appearing and then image is displayed after 1 sec.

So can anyone please tell me that what is the reason and how to sort out
this problem so that after launching the application image shud be displayed
not the screen.

Thanks-
Ritu Singh

[raj_J2ME]

Hello,

When you will click the icon of the app that have install on device, it will start loading the resources whatsoever you have load in the code. So that may take few milliseconds or even few seconds, that depends upon the resources that you are trying to load. If the resources are too heavy in size then it will show the while screen till the time loading is complete.

@ please share the widthxheight of the image and how many images are loading?
@ what is the size of the image in KB, or the total size of all the images?
@ on which device are you testing?

[ritusingh]

thanks for your quick reply....
i am sending you the code please tel me
how to resolve this issue.
Here is the code and i am testing it on n-86 device.
height and width is 320*388
and the size of the image is 131 kb.

package hello;
import java.util.Timer;
import java.util.TimerTask;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import javax.microedition.lcdui.game.GameCanvas;



public class Midlet extends MIDlet
{
private Display display;
private MyCanvas canvas;
//private MyCanvas1 canvas1;


public Midlet()
{
display= Display.getDisplay(this);
canvas=new MyCanvas();
//canvas1=new MyCanvas1();

}//end of ImmutableImageExample



public void startApp()
{
display.setCurrent(canvas);





}//end of startApp

public void pauseApp(){
}

public void destroyApp() {
try {
destroyApp(true);
} catch (MIDletStateChangeException ex) {
ex.printStackTrace();
}
notifyDestroyed();
}

public void exitMIDlet()
{

}//end of exitMIDlet

protected void destroyApp(boolean unconditional) throws MIDletStateChangeException {
throw new UnsupportedOperationException("Not supported yet.");
}

class MyCanvas extends Canvas
{


private Image objBKGImage = null;

public MyCanvas()
{
// super(true);




}







public void paint(Graphics g)
{


int iViewH = this.getHeight();
int iViewW = this.getWidth();



// load the background image
if (objBKGImage== null)
{
try
{

objBKGImage = Image.createImage("/aa.png");

objBKGImage = CreateScaledImage(objBKGImage, iViewW, iViewH);

} catch (Exception ex)
{
ex.printStackTrace();
}
}



// draw background
if (objBKGImage!= null)
g.drawImage(objBKGImage,
(int)iViewW / 2,
(int)iViewH / 2,
Graphics.VCENTER | Graphics.HCENTER );

}
public Image CreateScaledImage( Image imgOldImage, int iNewWidth, int iNewHeight )
{

Image imgNewImage = null;
final int iOldWidth = imgOldImage.getWidth();
final int iOldHeight = imgOldImage.getHeight();

int iOldRGBArray[] = new int[iOldWidth * iOldHeight];

imgOldImage.getRGB( iOldRGBArray, 0, iOldWidth, 0, 0, iOldWidth, iOldHeight);

int iNewRGBArray[] = new int[iNewWidth * iNewHeight];

for (int yy = 0; yy < iNewHeight; yy++)
{
int dy = yy * iOldHeight / iNewHeight;

for (int xx = 0; xx < iNewWidth; xx++)
{
int dx = xx * iOldWidth / iNewWidth;

iNewRGBArray[(iNewWidth * yy) + xx] = iOldRGBArray[(iOldWidth * dy) + dx];
}
}

imgNewImage = Image.createRGBImage(iNewRGBArray, iNewWidth, iNewHeight, true);

return imgNewImage;

}
}
}

[raj_J2ME]

Hi,
First of all we would like to know the total size of the images that you are loading.

[ritusingh]

thanks for ur reply....

the size of the image which i am loading is 131 kb.


thanks-
ritu

[raj_J2ME]

Hello,
You are doing the things a bit wrong,
You are loading the image in the paint method. Kindly load the images always in the canvas constructor.
Kindly have a look over the code here,
http://www.java2s.com/Code/Java/J2ME...eonacanvas.htm

[raj_J2ME]

thanks for ur reply....

the size of the image which i am loading is 131 kb.


thanks-
ritu

Though It is heavy image. however you try the code over the link that I gave before,and let us know whether that was helpful to you,

[amit_yadav]

hello ritusingh,
On device it is taking notable time because of

objBKGImage = CreateScaledImage(objBKGImage, iViewW, iViewH);

Amit

[ritusingh]

yes thanks for your suggestion.....
this one worked out.

Ritu