/*
* Copyright 2010-2011 Research In Motion Limited.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package blackberry.ui.dialog.select;
import net.rim.device.api.system.Bitmap;
import net.rim.device.api.ui.Color;
import net.rim.device.api.ui.Graphics;
/**
*
* @author Patchou
* @version 1.01
*
*/
public class GPATools
{
/**
* Resizes a bitmap with an alpha channel (transparency) without the artifacts introduced
* by <code>scaleInto()</code>.
*
* @param bmpSrc Source Bitmap
* @param nWidth New Width
* @param nHeight New Height
* @param nFilterType Filter quality to use. Can be <code>Bitmap.FILTER_LANCZOS</code>,
* <code>Bitmap.FILTER_BILINEAR</code> or
* <code>Bitmap.FILTER_BOX</code>.
* @param nAspectRatio Specifies how the picture is resized. Can be
* <code>Bitmap.SCALE_TO_FIT</code>,
* <code>Bitmap.SCALE_TO_FILL</code> or
* <code>Bitmap.SCALE_STRETCH</code>.
* @return The resized Bitmap in a new object.
*/
public static Bitmap ResizeTransparentBitmap(Bitmap bmpSrc, int nWidth, int nHeight, int nFilterType, int nAspectRatio)
{
if(bmpSrc == null)
return null;
//Get the original dimensions of the bitmap
int nOriginWidth = bmpSrc.getWidth();
int nOriginHeight = bmpSrc.getHeight();
if(nWidth == nOriginWidth && nHeight == nOriginHeight)
return bmpSrc;
//Prepare a drawing bitmap and graphic object
Bitmap bmpOrigin = new Bitmap(nOriginWidth, nOriginHeight);
Graphics graph = Graphics.create(bmpOrigin);
//Create a line of transparent pixels for later use
int[] aEmptyLine = new int[nWidth];
for(int x = 0; x < nWidth; x++)
aEmptyLine[x] = 0x00000000;
//Create two scaled bitmaps
Bitmap[] bmpScaled = new Bitmap[2];
for(int i = 0; i < 2; i++)
{
//Draw the bitmap on a white background first, then on a black background
graph.setColor((i == 0) ? Color.WHITE : Color.BLACK);
graph.fillRect(0, 0, nOriginWidth, nOriginHeight);
graph.drawBitmap(0, 0, nOriginWidth, nOriginHeight, bmpSrc, 0, 0);
//Create a new bitmap with the desired size
bmpScaled[i] = new Bitmap(nWidth, nHeight);
if(nAspectRatio == Bitmap.SCALE_TO_FIT)
{
//Set the alpha channel of all pixels to 0 to ensure transparency is
//applied around the picture, if needed by the transformation
for(int y = 0; y < nHeight; y++)
bmpScaled[i].setARGB(aEmptyLine, 0, nWidth, 0, y, nWidth, 1);
}
//Scale the bitmap
bmpOrigin.scaleInto(bmpScaled[i], nFilterType, nAspectRatio);
}
//Prepare objects for final iteration
Bitmap bmpFinal = bmpScaled[0];
int[][] aPixelLine = new int[2][nWidth];
//Iterate every line of the two scaled bitmaps
for(int y = 0; y < nHeight; y++)
{
bmpScaled[0].getARGB(aPixelLine[0], 0, nWidth, 0, y, nWidth, 1);
bmpScaled[1].getARGB(aPixelLine[1], 0, nWidth, 0, y, nWidth, 1);
//Check every pixel one by one
for(int x = 0; x < nWidth; x++)
{
//If the pixel was untouched (alpha channel still at 0), keep it transparent
if(((aPixelLine[0][x] >> 24) & 0xff) == 0)
aPixelLine[0][x] = 0x00000000;
else
{
//Compute the alpha value based on the difference of intensity
//in the red channel
int nAlpha = ((aPixelLine[1][x] >> 16) & 0xff) -
((aPixelLine[0][x] >> 16) & 0xff) + 255;
if(nAlpha == 0)
aPixelLine[0][x] = 0x00000000; //Completely transparent
else if(nAlpha >= 255)
aPixelLine[0][x] |= 0xff000000; //Completely opaque
else
{
//Compute the value of the each channel one by one
int nRed = ((aPixelLine[0][x] >> 16 ) & 0xff);
int nGreen = ((aPixelLine[0][x] >> 8 ) & 0xff);
int nBlue = (aPixelLine[0][x] & 0xff);
nRed = (int)(255 + (255.0 * ((double)(nRed-255)/(double)nAlpha)));
nGreen = (int)(255 + (255.0 * ((double)(nGreen-255)/(double)nAlpha)));
nBlue = (int)(255 + (255.0 * ((double)(nBlue-255)/(double)nAlpha)));
if(nRed < 0) nRed = 0;
if(nGreen < 0) nGreen = 0;
if(nBlue < 0) nBlue = 0;
aPixelLine[0][x] = nBlue | (nGreen<<8) | (nRed<<16) | (nAlpha<<24);
}
}
}
//Change the pixels of this line to their final value
bmpFinal.setARGB(aPixelLine[0], 0, nWidth, 0, y, nWidth, 1);
}
return bmpFinal;
}
}