Thursday, October 2, 2008

Showing a Splash

When customizing the User Interface with Canvas you can obtain the screen resolution with getWidth and getHight methods. Lets say you want to show a Splash screen to the user and have an image with your logo. How would you use it?
Well, a single image will not fit all screens. But two will do.
The smaller logo image should be less than 96x54, as this is the smallest screen resolution. This image can be used up to the resolution of 128x128 without problems. With bigger resolutions it will look tiny, though.
The bigger logo image should be a bit bigger than 128x128 and can be used up to 240x320.
The code bellow gives as example of how to implement this.

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

class Splash extends javax.microedition.lcdui.Canvas {

  Image logo;

  Splash () {
    if (getWidth() <= 128) {
      // sl stands for Small Logo and does not need to have a file extension
      // this will use less space on the jar file
      logo = Image.createImage("/sl");
    } else {
      // bl stands for Big Logo
      logo = Image.createImage("/bl");

  protected void paint (Graphics g) {
    // With these anchors your logo image will be drawn on the center of the screen.
    g.drawImage(logo, getWidth()/2, getHeight()/2, Graphics.HCENTER | Graphics.VCENTER);

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