Draw Gradient in Java ME
(A class to draw gradients in J2ME) |
hamishwillee
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| − | [[Category:Java]][[Category: | + | [[Category:Java ME]][[Category:Code Examples]][[Category:UI]][[Category:Graphics]] |
| + | {{Abstract|Here is a [[J2ME]] class for gradients drawing, supporting both horizontal and vertical gradients.}} | ||
| − | + | [[File:J2me_gradients.jpg]] | |
| − | + | ||
| − | + | ||
This could be useful to substitute background gradient images with graphics drawn by code. | This could be useful to substitute background gradient images with graphics drawn by code. | ||
<code java> | <code java> | ||
| − | |||
| − | |||
import javax.microedition.lcdui.Graphics; | import javax.microedition.lcdui.Graphics; | ||
| Line 20: | Line 17: | ||
{ | { | ||
int max = orientation == VERTICAL ? height : width; | 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) | if(orientation == VERTICAL) | ||
g.drawLine(left, top + i, left + width - 1, top + i); | g.drawLine(left, top + i, left + width - 1, top + i); | ||
| Line 32: | Line 41: | ||
g.drawLine(left + i, top, left + i, top + height - 1); | g.drawLine(left + i, top, left + i, top + height - 1); | ||
} | } | ||
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} | } | ||
} | } | ||
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<code java> | <code java> | ||
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import javax.microedition.lcdui.Canvas; | import javax.microedition.lcdui.Canvas; | ||
import javax.microedition.lcdui.Graphics; | import javax.microedition.lcdui.Graphics; | ||
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public class GradientRectCanvas extends Canvas { | public class GradientRectCanvas extends Canvas { | ||
| Line 84: | Line 71: | ||
} | } | ||
</code> | </code> | ||
| + | <!-- Translation --> [[pt:Desenho gradiente, em Java ME]] | ||
| + | |||
| + | {{ArticleMetaData <!-- v1.1 --> | ||
| + | |sourcecode= [[Media:GradientRectMIDletSource.zip]] | ||
| + | |installfile= [[Media:GradientRectMIDletBinaries.zip]] | ||
| + | |devices= Nokia 7373, Nokia N82 | ||
| + | |sdk= [http://www.developer.nokia.com/Develop/Java/ Nokia SDK 1.0 for Java] | ||
| + | |platform= Series 40, Symbian | ||
| + | |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. --> | ||
| + | |keywords= Draw, Gradient, Canvas, Graphics | ||
| + | |id= <!-- Article Id (Knowledge base articles only) --> | ||
| + | |language= <!-- Language category code for non-English topics - e.g. Lang-Chinese --> | ||
| + | |translated-by= <!-- [[User:XXXX]] --> | ||
| + | |translated-from-title= <!-- Title only --> | ||
| + | |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]] | ||
| + | }} | ||
Latest revision as of 01:05, 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)
