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

[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

[Razvan Cotty]

Hello guys,
Thank you for the code, it was extremely useful. However, I have noticed that on some phones it does not work if the image is very large as it has to create a huge array. So I have come up with an optimized version:

ResizeImage(Image image, int resizedWidth, int resizedHeight) {
  int[] in = null, out = null;

  int width = image.getWidth(), height = image.getHeight();
  in = new int[width]; 

  int i=0;
  int dy,dx; 
  out = new int[resizedWidth * resizedHeight]; 

  for (int y = 0; y < resizedHeight; y++) 
  { 
    dy = y * height / resizedHeight;
    
    image.getRGB(in,0,width,0,dy,width,1); 
    

    for (int x = 0; x < resizedWidth; x++) 
    { 
      dx = x * width / resizedWidth; 
      
      out[(resizedWidth * y) + x] = in[dx];
    } 
  } 
  Image resized = Image.createRGBImage(out,resizedWidth,resizedHeight,true);
  return resized; 
}

What's good about it is that it loads the original image line by line and depending on the ratio it skips the lines from the original image that are not needed for the resize process.

[Campbell Ritchie]

Razvan Cotty welcome to the Ranch