com.google.gwt.sample.guestbook.client.CanvasCustom.java Source code

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Here is the source code for com.google.gwt.sample.guestbook.client.CanvasCustom.java

Source

package com.google.gwt.sample.guestbook.client;

import com.google.gwt.canvas.client.Canvas;
import com.google.gwt.canvas.dom.client.Context2d;
import com.google.gwt.canvas.dom.client.CssColor;
import com.google.gwt.core.client.GWT;
import com.google.gwt.uibinder.client.UiBinder;
import com.google.gwt.uibinder.client.UiFactory;
import com.google.gwt.uibinder.client.UiField;
import com.google.gwt.user.client.Random;
import com.google.gwt.user.client.ui.Composite;
import com.google.gwt.user.client.ui.Widget;

abstract public class CanvasCustom extends Composite {
    interface CanvasUiBinder extends UiBinder<Widget, CanvasCustom> {
    }

    private static CanvasUiBinder uiBinder = GWT.create(CanvasUiBinder.class);

    public static final int WIDTH = 400;
    public static final int HEIGHT = 400;

    protected static final int COLOUR_INCREMENT_VECTOR = 11;
    protected final int coordVector = 11;
    @UiField
    Canvas canvas;
    protected Context2d context;
    protected int x = 0, y = 0;
    protected CssColor colour;

    private int red = 172;
    private int green = 172;
    private int blue = 172;

    public CanvasCustom() {
        initWidget(uiBinder.createAndBindUi(this));
        context = canvas.getContext2d();
        canvas.setWidth(WIDTH + "px");
        canvas.setHeight(HEIGHT + "px");
        canvas.setCoordinateSpaceWidth(WIDTH);
        canvas.setCoordinateSpaceHeight(HEIGHT);
    }

    public void init() {
    };

    abstract public void updateCanvas();

    protected void randomIncrementColour() {
        colour = CssColor.make(red = randomIncrementColourComponent(red),
                green = randomIncrementColourComponent(green), blue = randomIncrementColourComponent(blue));
    }

    private static int randomIncrementColourComponent(int colour) {
        int min = (COLOUR_INCREMENT_VECTOR - 1) / 2;
        int rand = Random.nextInt(COLOUR_INCREMENT_VECTOR);
        int vect = rand - min;
        colour = colour + vect;
        //       colour = (byte)(   colour + (  Random.nextInt(COLOUR_INCREMENT_VECTOR) - ( (COLOUR_INCREMENT_VECTOR-1) / 2 )  )   );
        if (colour < 0) {
            colour = 0;
        } else if (colour > 255) {
            colour = 255;
        }
        return colour;
    }

    @UiFactory
    public Canvas getCanvas() {
        //      canvas = Canvas.createIfSupported();
        //      if( canvas == null ){
        //TODO make alternative or a blank box of the same size.
        //      }
        return Canvas.createIfSupported();
    }
}