Can we resize the image in j2me

[Praveen india]

Can we resize the image in j2me so that bigger dimention image can fit into
the mobile screen.
My actual task in to zoom in and out the image
[ February 23, 2005: Message edited by: Praveen india ]

[Michael Yuan]

You cannot resize the in-memory image unless you understand the encoding algorithm. But when you draw the image on screen, you can map each screen pixel to several pixels on the image -- effectively smooth it and reduce its display size.

[Jari Kemppinen]

Here is a piece of code I use to display a resized image. Hope it helps.

private Image createThumbnail(Image image)
{
   int sourceWidth = image.getWidth();
   int sourceHeight = image.getHeight();
   int thumbWidth = 64;
   int thumbHeight = -1;
 
   if (thumbHeight == -1)
      thumbHeight = thumbWidth * sourceHeight / sourceWidth;
 
   Image thumb = Image.createImage(thumbWidth, thumbHeight);
   Graphics g = thumb.getGraphics();
 
   for (int y = 0; y < thumbHeight; y++)
   {
      for (int x = 0; x < thumbWidth; x++)
      {
        g.setClip(x, y, 1, 1);
        int dx = x * sourceWidth / thumbWidth;
        int dy = y * sourceHeight / thumbHeight;
        g.drawImage(image, x - dx, y - dy, Graphics.LEFT | Graphics.TOP);
      }
   }
 
   Image immutableThumb = Image.createImage(thumb);
 
   return immutableThumb;
}

Let's make this great code more readable using CODE tags. - Mark
[ May 15, 2005: Message edited by: Mark Spritzler ]

[Praveen india]

Thank you Jari Kemppinen for this code,
Now my problem is that when I make bigger picture to Thumbnail image
it works fine, the quality of picture is also good,
but when I use the same method in which I passed Thumbnail image as
parameter and changed the thumbWidth,thumbHeight values,to get the bigger
image the quality of picture is not good.
But if I use the original image to fit the screen I am getting java.lang.OutOfMemoryError if the image is bigger the screen size.
if the image is small the screen size, so the error dosen't cum
can u help me
[ February 24, 2005: Message edited by: Praveen india ]

[Nitin India]

Hi Jari,

tht code was really gud, but i have one query when i tried this code on transparent image it showed me white pixels on transparent area.

can i remove these these white pixels.

thnks

[Jari Kemppinen]

Sorry I can't help you guys any further, haven't got time to look into the problems you are having. If you find a solution please post it up to help other people with similar problems.

[Nitin India]

Hi all..

can any one help. i hv same question which i asked in my previous post.

though i hv done few things but was unsuccessful. its related to changing a alpha channel in a png image using nokia UI API.

can some one help.

thnks

[ApxA Corporation]

Hello,
I try your sample about resize but i use it in a streaming jpg mode and i wonder if we can optimized the code to speed up.
The process with "for" in "for" lose time with an image (320x240)
Best regards,

[LuisMiguel Rubio]

Hello. Thanks for your code. I've created other faster than yours, but i think it could be faster with some changes. And the more important, can resize images with transparent pixels.

It works with RGBArrays. First, we need a function to resize Arrays:

private int[] reescalaArray(int[] ini, int x, int y, int x2, int y2) {
int out[] = new int[x2*y2];
for (int yy = 0; yy < y2; yy++) {
int dy = yy * y / y2;
for (int xx = 0; xx < x2; xx++) {
int dx = xx * x / x2;
out[(x2*yy)+xx]=ini[(x*dy)+dx];
}
}
return out;
}

INI: Source Array
X: Width of Source Array
Y: Height of Source Array
X2: Width of the Output Array
Y2: Height of the Output Array
Returns OUT (Output Array)

How to use it:

//Need an image
Image temp=null;
try {
temp = Image.createImage("/tr1.gif");
} catch (IOException e) {
System.err.println("Can`t load the image : " + e.toString());
}
//Need an array (for RGB, with the size of original image)
int rgb[] = new int[temp.getWidth()*temp.getHeight()];
//Get the RGB array of image into "rgb"
temp.getRGB(rgb,0,temp.getWidth(),0,0,temp.getWidth(),temp.getHeight());
//Call to our function and obtain RGB2
int rgb2[] = reescalaArray(rgb,temp.getWidth(),temp.getHeight(),newX,newY);
//Create an image with that RGB array
Image temp2 = Image.createRGBImage(rgb2,newX,newY,true);

Et voil�. Next, i will modify a bit the "reescalaArray" function to improve more speed. If you get better results, please, share the solution

Happy summer!!

PD: Sorry my English, but i am Spanish
[ July 27, 2005: Message edited by: LuisMiguel Rubio ]

[Mark Cowan]

Thanks LuisMiguel,

Your code works perfectly. It really solves the problem of how to resize an image.

[Tim Holloway]

Welcome to the JavaRanch, Mark!

You've "awakened a zombie". LuisMiguel posted that message 5 years ago. In this business that means that he's probably gone on to at least 2 other employers since he posted. And that's assuming he didn't quit the profession entirely.

We're glad that this thread was helpful to you, but I wouldn't count on LuisMiguel answering you!

[Mark Cowan]

Tim - that's okay. It's import to thank him and to let other's know that his code works well.

[swaroop venu]

Thanks LuisMiguel, it works great...i have modified a bit..to make it faster also helps in freeing up memory


Image image1=reescalaArray(image,image.getWidth(),image.getHeight(),newX,newY);

Image reescalaArray(Image temp, int x, int y, int x2, int y2) {
int ini[] = new int[temp.getWidth()*temp.getHeight()];
//Get the RGB array of image into "rgb"

int i=0,t2;
int dy,dx;
temp.getRGB(ini,0,temp.getWidth(),0,0,temp.getWidth(),temp.getHeight());
int out[] = new int[x2*y2];
//t1=y/y2;
t2=x/x2;
for (int yy = 0; yy < y2; yy++) {
dy = yy *y/y2;

for (int xx = 0; xx < x2; xx++) {
dx = xx * t2;

out[i++]=ini[(x*dy)+dx]; //(x2*yy)+xx
}
}
Image temp3 = Image.createRGBImage(out,getWidth(),getHeight(),true);
return temp3;
}

[swaroop venu]

swaroop venu wrote:Thanks LuisMiguel, it works great...

[swaroop venu]

[Dhanushka Nayanananda]

Ya. .. It s perfect.. Thank you very much