Draw Gradient in Java ME
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<!-- Translation --> [[pt:Desenho gradiente, em Java ME]] | <!-- Translation --> [[pt:Desenho gradiente, em Java ME]] | ||
| − | {{ArticleMetaData | + | {{ArticleMetaData <!-- v1.1 --> |
| − | + | |sourcecode= [[Media:GradientRectMIDletSource.zip]] | |
| − | |sourcecode=[[Media:GradientRectMIDletSource.zip]] | + | |installfile= [[Media:GradientRectMIDletBinaries.zip]] |
| − | |installfile=[[Media:GradientRectMIDletBinaries.zip]] | + | |devices= Nokia 7373, Nokia N82 |
| − | |devices=Nokia 7373, Nokia N82 | + | |sdk= [http://www.developer.nokia.com/Develop/Java/ Nokia SDK 1.0 for Java] |
| − | |sdk=[http://www.developer.nokia.com/Develop/Java/ Nokia SDK 1.0 for Java] | + | |platform= Series 40, Symbian |
| − | |platform=Series 40, Symbian | + | |devicecompatability= MIDP2.0/CLDC 1.1 |
| − | |devicecompatability=MIDP2.0/CLDC 1.1 | + | |dependencies= <!-- Any other/external dependencies e.g.: Google Maps Api v1.0 --> |
| − | | | + | |signing= <!-- Signing requirements - empty or one of: Self-Signed, DevCert, Manufacturer --> |
| − | | | + | |capabilities= <!-- Capabilities required by the article/code example (e.g. Location, NetworkServices. --> |
| − | |capabilities=<!-- Capabilities required by the article/code example (e.g. Location, NetworkServices. --> | + | |
|keywords= Draw, Gradient, Canvas, Graphics | |keywords= Draw, Gradient, Canvas, Graphics | ||
|id= <!-- Article Id (Knowledge base articles only) --> | |id= <!-- Article Id (Knowledge base articles only) --> | ||
| − | | | + | |language= <!-- Language category code for non-English topics - e.g. Lang-Chinese --> |
| − | | | + | |translated-by= <!-- [[User:XXXX]] --> |
| − | |update-by=[[User:tiviinik]] | + | |translated-from-title= <!-- Title only --> |
| − | |update-timestamp=20120116}} | + | |translated-from-id= <!-- Id of translated revision --> |
| + | |review-by= <!-- After re-review: [[User:username]] --> | ||
| + | |review-timestamp= <!-- After re-review: YYYYMMDD --> | ||
| + | |update-by= [[User:tiviinik]] | ||
| + | |update-timestamp= 20120116 | ||
| + | |creationdate= 20080411 | ||
| + | |author= [[User:jappit]] | ||
| + | }} | ||
Revision as of 00:59, 23 January 2012
Here is a J2ME class for gradients drawing, supporting both horizontal and vertical gradients.
This could be useful to substitute background gradient images with graphics drawn by code.
import javax.microedition.lcdui.Graphics;
public class Gradient
{
public static final int VERTICAL = 0;
public static final int HORIZONTAL = 1;
public static void gradientBox(Graphics g, int color1, int color2, int left, int top, int width, int height, int orientation)
{
int max = orientation == VERTICAL ? height : width;
int color1RGB[] = new int[]{(color1>>16) & 0xff,(color1>>8) & 0xff,color1 & 0xff};
int color2RGB[] = new int[]{(color2>>16) & 0xff,(color2>>8) & 0xff,color2 & 0xff};
int colorCalc[] = new int[]{
(( color2RGB[0] - color1RGB[0] )<<16)/max,
(( color2RGB[1] - color1RGB[1] )<<16)/max,
(( color2RGB[2] - color1RGB[2] )<<16)/max
};
for(int i = max; i > -1; i--)
{
g.setColor(
(color1RGB[0]+((i*colorCalc[0])>>16)) <<16 |
(color1RGB[1]+((i*colorCalc[1])>>16)) <<8 |
(color1RGB[2]+((i*colorCalc[2])>>16))
);
if(orientation == VERTICAL)
g.drawLine(left, top + i, left + width - 1, top + i);
else
g.drawLine(left + i, top, left + i, top + height - 1);
}
}
}
and here is a sample Canvas using the gradientBox method (the final effect is shown in the screenshot at beginning of this article):
import javax.microedition.lcdui.Canvas;
import javax.microedition.lcdui.Graphics;
public class GradientRectCanvas extends Canvas {
protected void paint(Graphics g)
{
int halfWidth = getWidth() / 2;
int halfHeight = getHeight() / 2;
Gradient.gradientBox(g, 0xffffff, 0xff0000, 0, 0, halfWidth, halfHeight, Gradient.HORIZONTAL);
Gradient.gradientBox(g, 0xff0000, 0xffffff, halfWidth, 0, halfWidth, halfHeight, Gradient.VERTICAL);
Gradient.gradientBox(g, 0xffff00, 0x00ffff, 0, halfHeight, halfWidth, halfHeight, Gradient.VERTICAL);
Gradient.gradientBox(g, 0x00ff00, 0x0000ff, halfWidth, halfHeight, halfWidth, halfHeight, Gradient.VERTICAL);
}
}
Article Metadata
Code Example
Source file: Media:GradientRectMIDletSource.zip
Installation file: Media:GradientRectMIDletBinaries.zip
Tested with
Devices(s): Nokia 7373, Nokia N82
Compatibility
Platform(s): Series 40, Symbian
Device(s): MIDP2.0/CLDC 1.1
Article
Keywords: Draw, Gradient, Canvas, Graphics
Created: jappit
(11 Apr 2008)
Updated: tiviinik
(16 Jan 2012)
Last edited: hamishwillee
(23 Jan 2012)
