flash as3 加載bmp格式圖檔

主時間軸：

import BMPDecoder;

loadBMPFile("1.bmp");

function loadBMPFile(url:String ):void {

var loader:URLLoader = new URLLoader();

//指定loader以二進制傳回資料

loader.dataFormat = URLLoaderDataFormat.BINARY;

loader.addEventListener(Event.COMPLETE,loader_completeHandler);

loader.load( new URLRequest(url));

}

function loader_completeHandler( e:Event ):void {

var loader:URLLoader = e.target as URLLoader;

var decoder:BMPDecoder = new BMPDecoder();

//将二進制資料轉換成BitmapData

var bd:BitmapData = decoder.decode( loader.data );

//用來顯示效果的Bitmap擷取位圖資料，圖檔平滑

var myBitmap:Bitmap = new Bitmap(bd,"auto",true);

addChild(myBitmap);

}

BMPDecoder.as類：

package

{

import flash.display.BitmapData;

import flash.errors.IOError;

import flash.utils.ByteArray;

import flash.utils.Endian;

public class BMPDecoder {

private const BITMAP_HEADER_TYPE:String = "BM";

private const BITMAP_FILE_HEADER_SIZE:int = 14;

private const BITMAP_CORE_HEADER_SIZE:int = 12;

private const BITMAP_INFO_HEADER_SIZE:int = 40;

private const COMP_RGB :int = 0;

private const COMP_RLE8 :int = 1;

private const COMP_RLE4 :int = 2;

private const COMP_BITFIELDS:int = 3;

private const BIT1 :int = 1;

private const BIT4 :int = 4;

private const BIT8 :int = 8;

private const BIT16:int = 16;

private const BIT24:int = 24;

private const BIT32:int = 32;

private var bytes:ByteArray;

private var palette:Array;

private var bd:BitmapData;

private var nFileSize:uint;

private var nReserved1:uint;

private var nReserved2:uint;

private var nOffbits:uint;

private var nInfoSize:uint;

private var nWidth:int;

private var nHeight:int;

private var nPlains:uint;

private var nBitsPerPixel:uint;

private var nCompression:uint;

private var nSizeImage:uint;

private var nXPixPerMeter:int;

private var nYPixPerMeter:int;

private var nColorUsed:uint;

private var nColorImportant:uint;

private var nRMask:uint;

private var nGMask:uint;

private var nBMask:uint;

private var nRPos:uint;

private var nGPos:uint;

private var nBPos:uint;

private var nRMax:uint;

private var nGMax:uint;

private var nBMax:uint;

public function BMPDecoder() {

nRPos = 0;

nGPos = 0;

nBPos = 0;

}

public function decode( data:ByteArray ):BitmapData {

bytes = data;

bytes.endian = Endian.LITTLE_ENDIAN;

bytes.position = 0;

readFileHeader();

nInfoSize = bytes.readUnsignedInt();

switch ( nInfoSize ) {

case BITMAP_CORE_HEADER_SIZE:

readCoreHeader();

break;

case BITMAP_INFO_HEADER_SIZE:

readInfoHeader();

break;

default:

readExtendedInfoHeader();

break;

}

bd = new BitmapData( nWidth, nHeight );

switch ( nBitsPerPixel ){

case BIT1:

readColorPalette();

decode1BitBMP();

break;

case BIT4:

readColorPalette();

if ( nCompression == COMP_RLE4 ){

decode4bitRLE();

} else {

decode4BitBMP();

}

break;

case BIT8:

readColorPalette();

if ( nCompression == COMP_RLE8 ){

decode8BitRLE();

} else {

decode8BitBMP();

}

break;

case BIT16:

readBitFields();

checkColorMask();

decode16BitBMP();

break;

case BIT24:

decode24BitBMP();

break;

case BIT32:

readBitFields();

checkColorMask();

decode32BitBMP();

break;

default:

throw new VerifyError("invalid bits per pixel : " + nBitsPerPixel );

}

return bd;

}

private function readFileHeader():void {

var fileHeader:ByteArray = new ByteArray();

fileHeader.endian = Endian.LITTLE_ENDIAN;

try {

bytes.readBytes( fileHeader, 0, BITMAP_FILE_HEADER_SIZE );

if ( fileHeader.readUTFBytes( 2 ) != BITMAP_HEADER_TYPE ){

throw new VerifyError("invalid bitmap header type");

}

nFileSize = fileHeader.readUnsignedInt();

nReserved1 = fileHeader.readUnsignedShort();

nReserved2 = fileHeader.readUnsignedShort();

nOffbits = fileHeader.readUnsignedInt();

} catch ( e:IOError ) {

throw new VerifyError("invalid file header");

}

private function readCoreHeader():void {

var coreHeader:ByteArray = new ByteArray();

coreHeader.endian = Endian.LITTLE_ENDIAN;

try {

bytes.readBytes( coreHeader, 0, BITMAP_CORE_HEADER_SIZE - 4 );

nWidth = coreHeader.readShort();

nHeight = coreHeader.readShort();

nPlains = coreHeader.readUnsignedShort();

nBitsPerPixel = coreHeader.readUnsignedShort();

} catch ( e:IOError ) {

throw new VerifyError("invalid core header");

}

private function readInfoHeader():void {

var infoHeader:ByteArray = new ByteArray();

infoHeader.endian = Endian.LITTLE_ENDIAN;

try {

bytes.readBytes( infoHeader, 0, BITMAP_INFO_HEADER_SIZE - 4 );

nWidth = infoHeader.readInt();

nHeight = infoHeader.readInt();

nPlains = infoHeader.readUnsignedShort();

nBitsPerPixel = infoHeader.readUnsignedShort();

nCompression = infoHeader.readUnsignedInt();

nSizeImage = infoHeader.readUnsignedInt();

nXPixPerMeter = infoHeader.readInt();

nYPixPerMeter = infoHeader.readInt();

nColorUsed = infoHeader.readUnsignedInt();

nColorImportant = infoHeader.readUnsignedInt();

} catch ( e:IOError ) {

throw new VerifyError("invalid info header");

}

private function readExtendedInfoHeader():void {

var infoHeader:ByteArray = new ByteArray();

infoHeader.endian = Endian.LITTLE_ENDIAN;

try {

bytes.readBytes( infoHeader, 0, nInfoSize - 4 );

nWidth = infoHeader.readInt();

nHeight = infoHeader.readInt();

nPlains = infoHeader.readUnsignedShort();

nBitsPerPixel = infoHeader.readUnsignedShort();

nCompression = infoHeader.readUnsignedInt();

nSizeImage = infoHeader.readUnsignedInt();

nXPixPerMeter = infoHeader.readInt();

nYPixPerMeter = infoHeader.readInt();

nColorUsed = infoHeader.readUnsignedInt();

nColorImportant = infoHeader.readUnsignedInt();

if ( infoHeader.bytesAvailable >= 4 ) nRMask = infoHeader.readUnsignedInt();

if ( infoHeader.bytesAvailable >= 4 ) nGMask = infoHeader.readUnsignedInt();

if ( infoHeader.bytesAvailable >= 4 ) nBMask = infoHeader.readUnsignedInt();

} catch ( e:IOError ) {

throw new VerifyError("invalid info header");

}

private function readBitFields():void {

if ( nCompression == COMP_RGB ){

if ( nBitsPerPixel == BIT16 ){

// RGB555

nRMask = 0x00007c00;

nGMask = 0x000003e0;

nBMask = 0x0000001f;

} else {

//RGB888;

nRMask = 0x00ff0000;

nGMask = 0x0000ff00;

nBMask = 0x000000ff;

}

} else if ( ( nCompression == COMP_BITFIELDS ) && ( nInfoSize < 52 ) ){

try {

nRMask = bytes.readUnsignedInt();

nGMask = bytes.readUnsignedInt();

nBMask = bytes.readUnsignedInt();

} catch ( e:IOError ) {

throw new VerifyError("invalid bit fields");

}

private function readColorPalette():void {

var i:int;

var len:int = ( nColorUsed > 0 ) ? nColorUsed : Math.pow( 2, nBitsPerPixel );

palette = new Array( len );

for ( i = 0; i < len; ++i ){

palette[ i ] = bytes.readUnsignedInt();

}

private function decode1BitBMP():void {

var x:int;

var y:int;

var i:int;

var col:int;

var buf:ByteArray = new ByteArray();

var line:int = nWidth / 8;

if ( line % 4 > 0 ){

line = ( ( line / 4 | 0 ) + 1 ) * 4;

}

try {

for ( y = nHeight - 1; y >= 0; --y ){

buf.length = 0;

bytes.readBytes( buf, 0, line );

for ( x = 0; x < nWidth; x += 8 ){

col = buf.readUnsignedByte();

for ( i = 0; i < 8; ++i ){

bd.setPixel( x + i, y, palette[ col >> ( 7 - i ) & 0x01 ] );

}

} catch ( e:IOError ) {

throw new VerifyError("invalid image data");

}

private function decode4bitRLE():void {

var x:int;

var y:int;

var i:int;

var n:int;

var col:int;

var data:uint;

var buf:ByteArray = new ByteArray();

try {

for ( y = nHeight - 1; y >= 0; --y ){

buf.length = 0;

while ( bytes.bytesAvailable > 0 ){

n = bytes.readUnsignedByte();

if ( n > 0 ){

data = bytes.readUnsignedByte();

for ( i = 0; i < n/2; ++i ){

buf.writeByte( data );

}

} else {

n = bytes.readUnsignedByte();

if ( n > 0 ){

bytes.readBytes( buf, buf.length, n/2 );

buf.position += n/2;

if ( n/2 + 1 >> 1 << 1 != n/2 ){

bytes.readUnsignedByte();

}

} else {

// EOL

break;

}

buf.position = 0;

for ( x = 0; x < nWidth; x += 2 ){

col = buf.readUnsignedByte();

bd.setPixel( x, y, palette[ col >> 4 ] );

bd.setPixel( x + 1, y, palette[ col & 0x0f ] );

}

} catch ( e:IOError ) {

throw new VerifyError("invalid image data");

}

private function decode4BitBMP():void {

var x:int;

var y:int;

var i:int;

var col:int;

var buf:ByteArray = new ByteArray();

var line:int = nWidth / 2;

if ( line % 4 > 0 ){

line = ( ( line / 4 | 0 ) + 1 ) * 4;

}

try {

for ( y = nHeight - 1; y >= 0; --y ){

buf.length = 0;

bytes.readBytes( buf, 0, line );

for ( x = 0; x < nWidth; x += 2 ){

col = buf.readUnsignedByte();

bd.setPixel( x, y, palette[ col >> 4 ] );

bd.setPixel( x + 1, y, palette[ col & 0x0f ] );

}

} catch ( e:IOError ) {

throw new VerifyError("invalid image data");

}

private function decode8BitRLE():void {

var x:int;

var y:int;

var i:int;

var n:int;

var col:int;

var data:uint;

var buf:ByteArray = new ByteArray();

try {

for ( y = nHeight - 1; y >= 0; --y ){

buf.length = 0;

while ( bytes.bytesAvailable > 0 ){

n = bytes.readUnsignedByte();

if ( n > 0 ){

data = bytes.readUnsignedByte();

for ( i = 0; i < n; ++i ){

buf.writeByte( data );

}

} else {

n = bytes.readUnsignedByte();

if ( n > 0 ){

bytes.readBytes( buf, buf.length, n );

buf.position += n;

if ( n + 1 >> 1 << 1 != n ){

bytes.readUnsignedByte();

}

} else {

// EOL

break;

}

buf.position = 0;

for ( x = 0; x < nWidth; ++x ){

bd.setPixel( x, y, palette[ buf.readUnsignedByte() ] );

}

} catch ( e:IOError ) {

throw new VerifyError("invalid image data");

}

private function decode8BitBMP():void {

var x:int;

var y:int;

var i:int;

var col:int;

var buf:ByteArray = new ByteArray();

var line:int = nWidth;

if ( line % 4 > 0 ){

line = ( ( line / 4 | 0 ) + 1 ) * 4;

}

try {

for ( y = nHeight - 1; y >= 0; --y ){

buf.length = 0;

bytes.readBytes( buf, 0, line );

for ( x = 0; x < nWidth; ++x ){

bd.setPixel( x, y, palette[ buf.readUnsignedByte() ] );

}

} catch ( e:IOError ) {

throw new VerifyError("invalid image data");

}

private function decode16BitBMP():void {

var x:int;

var y:int;

var col:int;

try {

for ( y = nHeight - 1; y >= 0; --y ){

for ( x = 0; x < nWidth; ++x ){

col = bytes.readUnsignedShort();

bd.setPixel( x, y, ( ( ( col & nRMask ) >> nRPos )*0xff/nRMax << 16 ) + ( ( ( col & nGMask ) >> nGPos )*0xff/nGMax << 8 ) + ( ( ( col & nBMask ) >> nBPos )*0xff/nBMax << 0 ) );

}

} catch ( e:IOError ) {

throw new VerifyError("invalid image data");

}

private function decode24BitBMP():void {

var x:int;

var y:int;

var col:int;

var buf:ByteArray = new ByteArray();

var line:int = nWidth * 3;

if ( line % 4 > 0 ){

line = ( ( line / 4 | 0 ) + 1 ) * 4;

}

try {

for ( y = nHeight - 1; y >= 0; --y ){

buf.length = 0;

bytes.readBytes( buf, 0, line );

for ( x = 0; x < nWidth; ++x ){

bd.setPixel( x, y, buf.readUnsignedByte() + ( buf.readUnsignedByte() << 8 ) + ( buf.readUnsignedByte() << 16 ) );

}

} catch ( e:IOError ) {

throw new VerifyError("invalid image data");

}

private function decode32BitBMP():void {

var x:int;

var y:int;

var col:int;

try {

for ( y = nHeight - 1; y >= 0; --y ){

for ( x = 0; x < nWidth; ++x ){

col = bytes.readUnsignedInt();

bd.setPixel( x, y, ( ( ( col & nRMask ) >> nRPos )*0xff/nRMax << 16 ) + ( ( ( col & nGMask ) >> nGPos )*0xff/nGMax << 8 ) + ( ( ( col & nBMask ) >> nBPos )*0xff/nBMax << 0 ) );

}

} catch ( e:IOError ) {

throw new VerifyError("invalid image data");

}

private function checkColorMask():void {

if ( ( nRMask & nGMask ) | ( nGMask & nBMask ) | ( nBMask & nRMask ) ){

throw new VerifyError("invalid bit fields");

}

while ( ( nRMask >> nRPos ) & 0x00000001 == 0 ){

nRPos++;

}

while ( ( nGMask >> nGPos ) & 0x00000001 == 0 ){

nGPos++;

}

while ( ( nBMask >> nBPos ) & 0x00000001 == 0 ){

nBPos++;

}

nRMax = nRMask >> nRPos;

nGMax = nGMask >> nGPos;

nBMax = nBMask >> nBPos;

}

public function traceInfo():void {

trace("---- FILE HEADER ----");

trace("nFileSize: " + nFileSize );

trace("nReserved1: " + nReserved1 );

trace("nReserved2: " + nReserved2 );

trace("nOffbits: " + nOffbits );

trace("---- INFO HEADER ----");

trace("nWidth: " + nWidth );

trace("nHeight: " + nHeight );

trace("nPlains: " + nPlains );

trace("nBitsPerPixel: " + nBitsPerPixel );

if ( nInfoSize >= 40 ){

trace("nCompression: " + nCompression );

trace("nSizeImage: " + nSizeImage );

trace("nXPixPerMeter: " + nXPixPerMeter );

trace("nYPixPerMeter: " + nYPixPerMeter );

trace("nColorUsed: " + nColorUsed );

trace("nColorUsed: " + nColorImportant );

}

if ( nInfoSize >= 52 ){

trace("nRMask: " + nRMask.toString( 2 ) );

trace("nGMask: " + nGMask.toString( 2 ) );

trace("nBMask: " + nBMask.toString( 2 ) );

}

flash as3 加載bmp格式圖檔

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