Divides argument image into a matrix of smaller images based on the allowed size. - Java javax.microedition.lcdui

Java examples for javax.microedition.lcdui:Image

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Description

Divides argument image into a matrix of smaller images based on the allowed size.

Demo Code


import javax.microedition.lcdui.Graphics;
import javax.microedition.lcdui.Image;

public class Main{
    /**//  w  ww.jav a 2 s  .  c  om
     * Divides argument image into a matrix of smaller images based on the allowed maxTexDim
     * size. The resulting Image[row][column] contains the smaller images.  
     * 
     * @param sourceImg
     * @param maxTexDim
     * @param texMatrix
     * @return the image matrix
     */
    public static Image[][] imageToTextureMatrix(Image sourceImg,
            int maxTexDim, Image[][] texMatrix) {
        if (null != sourceImg) {
            if (maxTexDim < 0)
                maxTexDim = 1 << 8;

            int imgW = sourceImg.getWidth();
            int imgH = sourceImg.getHeight();

            // define max img dim
            int maxImgDim = Math.max(imgW, imgH);

            // find minimum text dim that fits image
            int i = 0;
            while (maxImgDim > (1 << ++i))
                ;

            int minTexDimRespect = 1 << i;

            // is sub divisioning nessesary?
            if (minTexDimRespect <= maxTexDim) {
                //No subdivision

                //init texmatrix?
                if (null == texMatrix)
                    texMatrix = new Image[1][1];

                Image base = texMatrix[0][0] = Image.createImage(maxTexDim,
                        maxTexDim);

                Graphics g = base.getGraphics();

                //fill black
                g.setColor(0x000000);
                g.fillRect(0, 0, base.getWidth(), base.getHeight());

                // draw image on texture base
                g.drawImage(sourceImg, (base.getWidth() - imgW) >> 1,
                        (base.getHeight() - imgH) >> 1, 0);
            } else {
                //Sub division needed

                //define number of needed subdivisions
                int numSubTexPerRow = 0, numSubTexPerColumn = 0;

                while (maxTexDim * numSubTexPerRow < imgW)
                    ++numSubTexPerRow;

                while (maxTexDim * numSubTexPerColumn < imgH)
                    ++numSubTexPerColumn;

                //create texSet
                int totalNumSubTex = numSubTexPerRow * numSubTexPerColumn;
                int totalRowTexSetDim = numSubTexPerRow * maxTexDim;
                int totalColumnTexSetDim = numSubTexPerColumn * maxTexDim;

                //init texmatrix?
                if (null == texMatrix)
                    texMatrix = new Image[numSubTexPerColumn][numSubTexPerRow];

                //calc generel source image offset
                int xOffsetBase = (totalRowTexSetDim - imgW) >> 1;
                int yOffsetBase = (totalColumnTexSetDim - imgH) >> 1;

                i = 0;
                Image img;
                while (i < totalNumSubTex) {
                    //draw source image to subtex
                    int column = i % numSubTexPerRow;
                    int row = i / numSubTexPerRow;

                    if (null == texMatrix[row]
                            || null == texMatrix[row][column])
                        //create sub texture
                        texMatrix[row][column] = img = Image.createImage(
                                maxTexDim, maxTexDim);
                    else
                        img = texMatrix[row][column];

                    //get graphics handle and set default background to black
                    Graphics g = img.getGraphics();
                    g.setColor(0xFF000000);
                    g.fillRect(0, 0, img.getWidth(), img.getHeight());

                    //calc generel source image offset
                    int xOffset = xOffsetBase;
                    int yOffset = yOffsetBase;

                    //adjust offsets to current sub tex 
                    xOffset -= column * maxTexDim;
                    yOffset -= row * maxTexDim;

                    g.drawImage(sourceImg, xOffset, yOffset, 0);

                    ++i;
                }
            }

            return texMatrix;
        } else
            return null;
    }
}

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