Java image conversion to RGB565
- by Vladimir
I try to convert image to RGB565 format.
I read this image:
BufferedImage bufImg = ImageIO.read(imagePathFile);
sendImg = new BufferedImage(CONTROLLER_LCD_WIDTH/*320*/, CONTROLLER_LCD_HEIGHT/*240*/, BufferedImage.TYPE_USHORT_565_RGB);
sendImg .getGraphics().drawImage(bufImg, 0, 0, CONTROLLER_LCD_WIDTH/*320*/, CONTROLLER_LCD_HEIGHT/*240*/, null);
Here is it:
Then I convert it to RGB565:
int numByte=0;
byte[] OutputImageArray = new byte[CONTROLLER_LCD_WIDTH*CONTROLLER_LCD_HEIGHT*2];
int i=0;
int j=0;
int len = OutputImageArray.length;
for (i=0;i<CONTROLLER_LCD_WIDTH;i++) {
for (j=0;j<CONTROLLER_LCD_HEIGHT;j++) {
Color c = new Color(sendImg.getRGB(i, j));
int aRGBpix = sendImg.getRGB(i, j);
int alpha;
int red = c.getRed();
int green = c.getGreen();
int blue = c.getBlue();
//RGB888
red = (aRGBpix >> 16) & 0x0FF;
green = (aRGBpix >> 8) & 0x0FF;
blue = (aRGBpix >> 0) & 0x0FF;
alpha = (aRGBpix >> 24) & 0x0FF;
//RGB565
red = red >> 3;
green = green >> 2;
blue = blue >> 3;
//A pixel is represented by a 4-byte (32 bit) integer, like so:
//00000000 00000000 00000000 11111111
//^ Alpha ^Red ^Green ^Blue
//Converting to RGB565
short pixel_to_send = 0;
int pixel_to_send_int = 0;
pixel_to_send_int = (red << 11) | (green << 5) | (blue);
pixel_to_send = (short) pixel_to_send_int;
//dividing into bytes
byte byteH=(byte)((pixel_to_send >> 8) & 0x0FF);
byte byteL=(byte)(pixel_to_send & 0x0FF);
//Writing it to array - High-byte is second
OutputImageArray[numByte]=byteH;
OutputImageArray[numByte+1]=byteL;
numByte+=2;
}
}
Then I try to restore this from resulting array OutputImageArray:
i=0;
j=0;
numByte=0;
BufferedImage NewImg = new BufferedImage(CONTROLLER_LCD_WIDTH, CONTROLLER_LCD_HEIGHT, BufferedImage.TYPE_USHORT_565_RGB);
for (i=0;i<CONTROLLER_LCD_WIDTH;i++) {
for (j=0;j<CONTROLLER_LCD_HEIGHT;j++) {
int curPixel=0;
int alpha=0x0FF;
int red;
int green;
int blue;
byte byteL=0;
byte byteH=0;
byteH = OutputImageArray[numByte];
byteL = OutputImageArray[numByte+1];
curPixel= (byteH << 8) | (byteL);
//RGB565
red = (curPixel >> (6+5)) & 0x01F;
green = (curPixel >> 5) & 0x03F;
blue = (curPixel) & 0x01F;
//RGB888
red = red << 3;
green = green << 2;
blue = blue << 3;
//aRGB
curPixel = 0;
curPixel = (alpha << 24) | (red << 16) | (green << 8) | (blue);
NewImg.setRGB(i, j, curPixel);
numByte+=2;
}
}
I output this restored image. But I see that it looks very poor.
I expected the lost of pictures quality.
But as I thought, this picture has to have almost the same quality as the previous picture. - Is it right?
Is my code right?
