Chargement rapide et le dessin de données RVB dans BufferedImage

Après avoir joué un peu avec ce que j'ai une vie décente réponse qui fonctionne pour Windows si la configuration graphique est à l'aide de ARGB entier emballé rasters.

Ce que j'ai à faire est de créer le compatible BufferedImage d'abord, puis-je convertir manuellement mon RVB tableau d'octets à un ARGB tableau int. Puis-je obtenir la trame du compatible BufferedImage et d'écrire ma ARGB ints. C'est beaucoup plus rapide.

Moi aussi j'ai une classe qui vérifie si le compatible BufferedImage est dans le format que j'attends, si ce n'est pas la valeur par défaut est l'ancienne approche plus lente.

Ici, c'est la classe. Espérons qu'il vous aide.

/**
* This class can read chunks of RGB image data out of a file and return a BufferedImage.
* It may use an optimized technique for loading images that relies on assumptions about the 
* default image format on Windows.
*/
public class RGBImageLoader
{
private byte[] tempBuffer_;
private boolean fastLoading_;
public RGBImageLoader()
{
fastLoading_ = canUseFastLoadingTechnique();
}
private boolean canUseFastLoadingTechnique()
{
//Create an image that's compatible with the screen
GraphicsConfiguration gc = GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice().getDefaultConfiguration();
BufferedImage image = gc.createCompatibleImage(100, 100, Transparency.TRANSLUCENT);
//On windows this should be an ARGB integer packed raster. If it is then we can 
//use our optimization technique
if(image.getType() != BufferedImage.TYPE_INT_ARGB)
return false;
WritableRaster raster = image.getRaster();
if(!(raster instanceof IntegerInterleavedRaster))
return false;
if(!(raster.getDataBuffer() instanceof DataBufferInt))
return false;
if(!(image.getColorModel() instanceof DirectColorModel))
return false;
DirectColorModel colorModel = (DirectColorModel) image.getColorModel();
if(!(colorModel.getColorSpace() instanceof ICC_ColorSpace) ||
colorModel.getNumComponents() != 4 ||
colorModel.getAlphaMask() != 0xff000000 ||
colorModel.getRedMask() != 0xff0000 ||
colorModel.getGreenMask() != 0xff00 ||
colorModel.getBlueMask() != 0xff)
return false;
if(raster.getNumBands() != 4 ||
raster.getNumDataElements() != 1 ||
!(raster.getSampleModel() instanceof SinglePixelPackedSampleModel))
return false;
return true;
}
public BufferedImage loadImage(File file, int width, int height, long imageOffset) throws IOException
{
if(fastLoading_)
return loadImageUsingFastTechnique(file, width, height, imageOffset);
else
return loadImageUsingCompatibleTechnique(file, width, height, imageOffset);
}
private BufferedImage loadImageUsingFastTechnique(File file, int width, int height, long imageOffset) throws IOException
{
int sizeBytes = width * height * 3;
//Make sure buffer is big enough
if(tempBuffer_ == null || tempBuffer_.length < sizeBytes)
tempBuffer_ = new byte[sizeBytes];
RandomAccessFile raf = null;
try
{
raf = new RandomAccessFile(file, "r");
raf.seek(imageOffset);
int bytesRead = raf.read(tempBuffer_, 0, sizeBytes);
if (bytesRead != sizeBytes)
throw new IOException("Invalid byte count. Should be " + sizeBytes + " not " + bytesRead);
GraphicsConfiguration gc = GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice().getDefaultConfiguration();
BufferedImage image = gc.createCompatibleImage(width, height, Transparency.TRANSLUCENT);
WritableRaster raster = image.getRaster();
DataBufferInt dataBuffer = (DataBufferInt) raster.getDataBuffer();
addAlphaChannel(tempBuffer_, sizeBytes, dataBuffer.getData());
return image;
}
finally
{
try
{
if(raf != null)
raf.close();
}
catch(Exception ex)
{
}
}
}
private BufferedImage loadImageUsingCompatibleTechnique(File file, int width, int height, long imageOffset) throws IOException
{
int sizeBytes = width * height * 3;
RandomAccessFile raf = null;
try
{
raf = new RandomAccessFile(file, "r");
//Lets navigate to the offset
raf.seek(imageOffset);
DataBufferByte dataBuffer = new DataBufferByte(sizeBytes);
byte[] bytes = dataBuffer.getData();
int bytesRead = raf.read(bytes, 0, sizeBytes);
if (bytesRead != sizeBytes)
throw new IOException("Invalid byte count. Should be " + sizeBytes + " not " + bytesRead);
WritableRaster raster = Raster.createInterleavedRaster(dataBuffer, //dataBuffer
width, //width
height, //height
width * 3, //scanlineStride
3, //pixelStride
new int[]{0, 1, 2}, //bandOffsets
null); //location
ColorModel colorModel = new ComponentColorModel(ColorSpace.getInstance(ColorSpace.CS_sRGB), //ColorSpace
new int[]{8, 8, 8}, //bits
false, //hasAlpha
false, //isPreMultiplied
ComponentColorModel.OPAQUE, DataBuffer.TYPE_BYTE);
BufferedImage loadImage = new BufferedImage(colorModel, raster, false, null);
//Convert it into a buffered image that's compatible with the current screen.
//Not ideal creating this image twice....
BufferedImage image = createCompatibleImage(loadImage);
return image;
}
finally
{
try
{
if(raf != null)
raf.close();
}
catch(Exception ex)
{
}
}
}
private BufferedImage createCompatibleImage(BufferedImage image)
{
GraphicsConfiguration gc = GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice().getDefaultConfiguration();
BufferedImage newImage = gc.createCompatibleImage(image.getWidth(), image.getHeight(), Transparency.TRANSLUCENT);
Graphics2D g = newImage.createGraphics();
g.drawImage(image, 0, 0, null);
g.dispose();
return newImage;
}
private void addAlphaChannel(byte[] rgbBytes, int bytesLen, int[] argbInts)
{
for(int i=0, j=0; i<bytesLen; i+=3, j++)
{
argbInts[j] = ((byte) 0xff) << 24 |                 //Alpha
(rgbBytes[i] << 16) & (0xff0000) |      //Red
(rgbBytes[i+1] << 8) & (0xff00) |       //Green
(rgbBytes[i+2]) & (0xff);               //Blue
}
}
}

OriginalL'auteur awinbra